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Contents
iii
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x
General
Symbols Used in Log Interpretation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-1 . . . . . . . . . . . . . . . . . . . . . . 1
Estimation of Formation Temperature with Depth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-2 . . . . . . . . . . . . . . . . . . . . . . 3
Estimation of Rmf and Rmc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-3 . . . . . . . . . . . . . . . . . . . . . . 4
Equivalent NaCl Salinity of Salts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-4 . . . . . . . . . . . . . . . . . . . . . . 5
Concentration of NaCl Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-5 . . . . . . . . . . . . . . . . . . . . . . 6
Resistivity of NaCl Water Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-6 . . . . . . . . . . . . . . . . . . . . . . 8
Density of Water and Hydrogen Index of Water and Hydrocarbons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-7 . . . . . . . . . . . . . . . . . . . . . . 9
Density and Hydrogen Index of Natural Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-8 . . . . . . . . . . . . . . . . . . . . . 10
Sound Velocity of Hydrocarbons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-9 . . . . . . . . . . . . . . . . . . . . . 11
Gas Effect on Compressional Slowness. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-9a . . . . . . . . . . . . . . . . . . . 12
Gas Effect on Acoustic Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-9b . . . . . . . . . . . . . . . . . . . 13
Nuclear Magnetic Resonance Relaxation Times of Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-10 . . . . . . . . . . . . . . . . . . . 14
Nuclear Magnetic Resonance Relaxation Times of Hydrocarbons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-11a . . . . . . . . . . . . . . . . . . 15
Nuclear Magnetic Resonance Relaxation Times of Hydrocarbons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-11b . . . . . . . . . . . . . . . . . . 16
Capture Cross Section of NaCl Water Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-12 . . . . . . . . . . . . . . . . . . . 18
Capture Cross Section of NaCl Water Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-13 . . . . . . . . . . . . . . . . . . . 19
Capture Cross Section of Hydrocarbons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-14 . . . . . . . . . . . . . . . . . . . 21
EPT* Propagation Time of NaCl Water Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-15 . . . . . . . . . . . . . . . . . . . 22
EPT Attenuation of NaCl Water Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-16 . . . . . . . . . . . . . . . . . . . 23
EPT Propagation Time–Attenuation Crossplot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gen-16a . . . . . . . . . . . . . . . . . . 24
Gamma Ray
Scintillation Gamma Ray—33⁄8- and 111⁄16-in. Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-1 . . . . . . . . . . . . . . . . . . . . . . 25
Scintillation Gamma Ray—33⁄8- and 111⁄16-in. Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-2 . . . . . . . . . . . . . . . . . . . . . . 26
Scintillation Gamma Ray—33⁄8- and 111⁄16-in. Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-3 . . . . . . . . . . . . . . . . . . . . . . 27
SlimPulse* and E-Pulse* Gamma Ray Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-6 . . . . . . . . . . . . . . . . . . . . . . 28
ImPulse* Gamma Ray—4.75-in. Tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-7 . . . . . . . . . . . . . . . . . . . . . . 29
PowerPulse* and TeleScope* Gamma Ray—6.75-in. Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-9 . . . . . . . . . . . . . . . . . . . . . . 30
PowerPulse Gamma Ray—8.25-in. Normal-Flow Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-10 . . . . . . . . . . . . . . . . . . . . 31
PowerPulse Gamma Ray—8.25-in. High-Flow Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-11 . . . . . . . . . . . . . . . . . . . . 32
PowerPulse Gamma Ray—9-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-12 . . . . . . . . . . . . . . . . . . . . 33
PowerPulse Gamma Ray—9.5-in. Normal-Flow Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-13 . . . . . . . . . . . . . . . . . . . . 34
PowerPulse Gamma Ray—9.5-in. High-Flow Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-14 . . . . . . . . . . . . . . . . . . . . 35
geoVISION675* GVR* Gamma Ray—6.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-15 . . . . . . . . . . . . . . . . . . . . 36
RAB* Gamma Ray—8.25-in. Tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-16 . . . . . . . . . . . . . . . . . . . . 37
arcVISION475* Gamma Ray—4.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-19 . . . . . . . . . . . . . . . . . . . . 38
Contents
arcVISION675* Gamma Ray—6.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-20 . . . . . . . . . . . . . . . . . . . . 39
arcVISION825* Gamma Ray—8.25-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-21 . . . . . . . . . . . . . . . . . . . . 40
arcVISION900* Gamma Ray—9-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-22 . . . . . . . . . . . . . . . . . . . . 41
arcVISION475 Gamma Ray—4.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-23 . . . . . . . . . . . . . . . . . . . . 42
arcVISION675 Gamma Ray—6.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-24 . . . . . . . . . . . . . . . . . . . . 43
arcVISION825 Gamma Ray—8.25-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-25 . . . . . . . . . . . . . . . . . . . . 44
arcVISION900 Gamma Ray—9-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GR-26 . . . . . . . . . . . . . . . . . . . . 45
Spontaneous Potential
Rweq Determination from ESSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SP-1 . . . . . . . . . . . . . . . . . . . . . . 47
Rweq versus Rw and Formation Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SP-2 . . . . . . . . . . . . . . . . . . . . . . 48
Rweq versus Rw and Formation Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SP-3 . . . . . . . . . . . . . . . . . . . . . . 49
Bed Thickness Correction—Open Hole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SP-4 . . . . . . . . . . . . . . . . . . . . . . 51
Bed Thickness Correction—Open Hole (Empirical) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SP-5 . . . . . . . . . . . . . . . . . . . . . . 52
Bed Thickness Correction—Open Hole (Empirical) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SP-6 . . . . . . . . . . . . . . . . . . . . . . 53
Density
Porosity Effect on Photoelectric Cross Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dens-1. . . . . . . . . . . . . . . . . . . . 54
Apparent Log Density to True Bulk Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dens-2. . . . . . . . . . . . . . . . . . . . 55
Neutron
Dual-Spacing Compensated Neutron Tool Charts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Compensated Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-1 . . . . . . . . . . . . . . . . . . . . . 58
Compensated Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-2 . . . . . . . . . . . . . . . . . . . . . 59
Compensated Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-3 . . . . . . . . . . . . . . . . . . . . . 61
Compensated Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-4 . . . . . . . . . . . . . . . . . . . . . 62
Compensated Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-5 . . . . . . . . . . . . . . . . . . . . . 63
Compensated Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-6 . . . . . . . . . . . . . . . . . . . . . 65
Compensated Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-7 . . . . . . . . . . . . . . . . . . . . . 67
Compensated Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-8 . . . . . . . . . . . . . . . . . . . . . 69
Compensated Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-9 . . . . . . . . . . . . . . . . . . . . . 71
APS* Accelerator Porosity Sonde. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-10 . . . . . . . . . . . . . . . . . . . 73
APS Accelerator Porosity Sonde Without Environmental Corrections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-11 . . . . . . . . . . . . . . . . . . . 74
CDN* Compensated Density Neutron and adnVISION* Azimuthal Density Neutron Tools . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-30 . . . . . . . . . . . . . . . . . . . 76
adnVISION475* Azimuthal Density Neutron—4.75-in. Tool and 6-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-31 . . . . . . . . . . . . . . . . . . . 78
adnVISION475 BIP Neutron—4.75-in. Tool and 6-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-32 . . . . . . . . . . . . . . . . . . . 79
adnVISION475 Azimuthal Density Neutron—4.75-in. Tool and 8-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-33 . . . . . . . . . . . . . . . . . . . 80
adnVISION475 BIP Neutron—4.75-in. Tool and 8-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-34 . . . . . . . . . . . . . . . . . . . 81
Contents
iv
Contents
v
adnVISION675* Azimuthal Density Neutron—6.75-in. Tool and 8-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-35 . . . . . . . . . . . . . . . . . . . 82
adnVISION675 BIP Neutron—6.75-in. Tool and 8-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-36 . . . . . . . . . . . . . . . . . . . 83
adnVISION675 Azimuthal Density Neutron—6.75-in. Tool and 10-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-37 . . . . . . . . . . . . . . . . . . . 84
adnVISION675 BIP Neutron—6.75-in. Tool and 10-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-38 . . . . . . . . . . . . . . . . . . . 85
adnVISION825* Azimuthal Density Neutron—8.25-in. Tool and 12.25-in. Borehole. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-39 . . . . . . . . . . . . . . . . . . . 86
CDN Compensated Density Neutron and adnVISION825s* Azimuthal Density Neutron—8-in. Tool and 12-in. Borehole. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-40 . . . . . . . . . . . . . . . . . . . 87
CDN Compensated Density Neutron and adnVISION825s Azimuthal Density Neutron—8-in. Tool and 14-in. Borehole. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-41 . . . . . . . . . . . . . . . . . . . 88
CDN Compensated Density Neutron and adnVISION825s Azimuthal Density Neutron—8-in. Tool and 16-in. Borehole. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neu-42 . . . . . . . . . . . . . . . . . . . 89
Nuclear Magnetic Resonance
CMR* Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CMR-1 . . . . . . . . . . . . . . . . . . . . 90
Resistivity Laterolog
ARI* Azimuthal Resistivity Imager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-1 . . . . . . . . . . . . . . . . . . . . . 91
High-Resolution Azimuthal Laterolog Sonde (HALS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-2 . . . . . . . . . . . . . . . . . . . . . 92
High-Resolution Azimuthal Laterolog Sonde (HALS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-3 . . . . . . . . . . . . . . . . . . . . . 93
High-Resolution Azimuthal Laterolog Sonde (HALS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-4 . . . . . . . . . . . . . . . . . . . . . 94
High-Resolution Azimuthal Laterolog Sonde (HALS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-5 . . . . . . . . . . . . . . . . . . . . . 95
High-Resolution Azimuthal Laterolog Sonde (HALS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-6 . . . . . . . . . . . . . . . . . . . . . 96
High-Resolution Azimuthal Laterolog Sonde (HALS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-7 . . . . . . . . . . . . . . . . . . . . . 97
High-Resolution Azimuthal Laterolog Sonde (HALS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-8 . . . . . . . . . . . . . . . . . . . . . 98
High-Resolution Azimuthal Laterolog Sonde (HALS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-9 . . . . . . . . . . . . . . . . . . . . . 99
HRLA* High-Resolution Laterolog Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-10. . . . . . . . . . . . . . . . . . . 100
HRLA High-Resolution Laterolog Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-11. . . . . . . . . . . . . . . . . . . 101
HRLA High-Resolution Laterolog Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-12. . . . . . . . . . . . . . . . . . . 102
HRLA High-Resolution Laterolog Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-13. . . . . . . . . . . . . . . . . . . 103
HRLA High-Resolution Laterolog Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-14. . . . . . . . . . . . . . . . . . . 104
GeoSteering* Bit Resistivity—6.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-20. . . . . . . . . . . . . . . . . . . 105
GeoSteering arcVISION675 Resistivity—6.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-21. . . . . . . . . . . . . . . . . . . 106
GeoSteering Bit Resistivity in Reaming Mode—6.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-22. . . . . . . . . . . . . . . . . . . 107
geoVISION* Resistivity Sub—6.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-23. . . . . . . . . . . . . . . . . . . 108
geoVISION Resistivity Sub—8.25-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-24. . . . . . . . . . . . . . . . . . . 109
GeoSteering Bit Resistivity—6.75-in. Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-25. . . . . . . . . . . . . . . . . . . 110
CHFR* Cased Hole Formation Resistivity Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-50. . . . . . . . . . . . . . . . . . . 111
CHFR Cased Hole Formation Resistivity Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-51. . . . . . . . . . . . . . . . . . . 112
CHFR Cased Hole Formation Resistivity Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RLl-52. . . . . . . . . . . . . . . . . . . 113
Resistivity Induction
AIT* Array Induction Imager Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RInd-1 . . . . . . . . . . . . . . . . . . 115
AIT Array Induction Imager Tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Resistivity Electromagnetic
arcVISION475 and ImPulse 43⁄4-in. Drill Collar Resistivity Tools—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-11 . . . . . . . . . . . . . . . . . 121
arcVISION475 and ImPulse 43⁄4-in. Drill Collar Resistivity Tools—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-12 . . . . . . . . . . . . . . . . . 122
arcVISION475 and ImPulse 43⁄4-in. Drill Collar Resistivity Tools—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-13 . . . . . . . . . . . . . . . . . 123
arcVISION475 and ImPulse 43⁄4-in. Drill Collar Resistivity Tools—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-14 . . . . . . . . . . . . . . . . . 124
arcVISION675 63⁄4-in. Drill Collar Resistivity Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-15 . . . . . . . . . . . . . . . . . 125
arcVISION675 63⁄4-in. Drill Collar Resistivity Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-16 . . . . . . . . . . . . . . . . . 126
arcVISION675 63⁄4-in. Drill Collar Resistivity Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-17 . . . . . . . . . . . . . . . . . 127
arcVISION675 63⁄4-in. Drill Collar Resistivity Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-18 . . . . . . . . . . . . . . . . . 128
arcVISION675 63⁄4-in. Drill Collar Resistivity Tool—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-19 . . . . . . . . . . . . . . . . . 129
arcVISION675 63⁄4-in. Drill Collar Resistivity Tool—2 MHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-20 . . . . . . . . . . . . . . . . . 130
arcVISION675 63⁄4-in. Drill Collar Resistivity Tool—2 MHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-21 . . . . . . . . . . . . . . . . . 131
arcVISION675 63⁄4-in. Drill Collar Resistivity Tool—2 MHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-22 . . . . . . . . . . . . . . . . . 132
arcVISION825 81⁄4-in. Drill Collar Resistivity Tool—400 kHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-23 . . . . . . . . . . . . . . . . . 133
arcVISION825 81⁄4-in. Drill Collar Resistivity Tool—400 kHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-24 . . . . . . . . . . . . . . . . . 134
arcVISION825 81⁄4-in. Drill Collar Resistivity Tool—400 kHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-25 . . . . . . . . . . . . . . . . . 135
arcVISION825 81⁄4-in. Drill Collar Resistivity Tool—400 kHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-26 . . . . . . . . . . . . . . . . . 136
arcVISION825 81⁄4-in. Drill Collar Resistivity Tool—2 MHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-27 . . . . . . . . . . . . . . . . . 137
arcVISION825 81⁄4-in. Drill Collar Resistivity Tool—2 MHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-28 . . . . . . . . . . . . . . . . . 138
arcVISION825 81⁄4-in. Drill Collar Resistivity Tool—2 MHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-29 . . . . . . . . . . . . . . . . . 139
arcVISION825 81⁄4-in. Drill Collar Resistivity Tool—2 MHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-30 . . . . . . . . . . . . . . . . . 140
arcVISION900 9-in. Drill Collar Resistivity Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-31 . . . . . . . . . . . . . . . . . 141
arcVISION900 9-in. Drill Collar Resistivity Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-32 . . . . . . . . . . . . . . . . . 142
arcVISION900 9-in. Drill Collar Resistivity Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-33 . . . . . . . . . . . . . . . . . 143
arcVISION900 9-in. Drill Collar Resistivity Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-34 . . . . . . . . . . . . . . . . . 144
arcVISION900 9-in. Drill Collar Resistivity Tool—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-35 . . . . . . . . . . . . . . . . . 145
arcVISION900 9-in. Drill Collar Resistivity Tool—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-36 . . . . . . . . . . . . . . . . . 146
arcVISION900 9-in. Drill Collar Resistivity Tool—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-37 . . . . . . . . . . . . . . . . . 147
arcVISION900 9-in. Drill Collar Resistivity Tool—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-38 . . . . . . . . . . . . . . . . . 148
Contents
vi
Contents
vii
arcVISION675, arcVISION825, and arcVISION900 Array Resistivity Compensated Tools—400 kHz . . . . . . . . . . . . . . . . REm-55 . . . . . . . . . . . . . . . . . 150
arcVISION and ImPulse Array Resistivity Compensated Tools—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . REm-56 . . . . . . . . . . . . . . . . . 151
arcVISION675 and ImPulse Array Resistivity Compensated Tools—2 MHz and 16-in. Spacing . . . . . . . . . . . . . . . . . . . . . REm-58 . . . . . . . . . . . . . . . . . 152
arcVISION675 and ImPulse Array Resistivity Compensated Tools—2 MHz and 22-in. Spacing . . . . . . . . . . . . . . . . . . . . . REm-59 . . . . . . . . . . . . . . . . . 153
arcVISION675 and ImPulse Array Resistivity Compensated Tools—2 MHz and 28-in. Spacing . . . . . . . . . . . . . . . . . . . . . REm-60 . . . . . . . . . . . . . . . . . 154
arcVISION675 and ImPulse Array Resistivity Compensated Tools—2 MHz and 34-in. Spacing . . . . . . . . . . . . . . . . . . . . . REm-61 . . . . . . . . . . . . . . . . . 155
arcVISION675 and ImPulse Array Resistivity Compensated Tools—2 MHz and 40-in. Spacing . . . . . . . . . . . . . . . . . . . . . REm-62 . . . . . . . . . . . . . . . . . 156
arcVISION675 and ImPulse Array Resistivity Compensated Tools—2 MHz with Dielectric Assumption . . . . . . . . . . . REm-63 . . . . . . . . . . . . . . . . . 157
Formation Resistivity
Resistivity Galvanic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-1 . . . . . . . . . . . . . . . . . . . . . 158
High-Resolution Azimuthal Laterlog Sonde (HALS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-2 . . . . . . . . . . . . . . . . . . . . . 159
High-Resolution Azimuthal Laterlog Sonde (HALS). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-3 . . . . . . . . . . . . . . . . . . . . . 160
geoVISION675* Resistivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-10 . . . . . . . . . . . . . . . . . . . . 161
geoVISION675 Resistivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-11 . . . . . . . . . . . . . . . . . . . . 162
geoVISION675 Resistivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-12 . . . . . . . . . . . . . . . . . . . . 163
geoVISION675 Resistivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-13 . . . . . . . . . . . . . . . . . . . . 164
geoVISION825* 81⁄4-in. Resistivity-at-the-Bit Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-14 . . . . . . . . . . . . . . . . . . . . 165
geoVISION825 81⁄4-in. Resistivity-at-the-Bit Tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-15 . . . . . . . . . . . . . . . . . . . . 166
geoVISION825 81⁄4-in. Resistivity-at-the-Bit Tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-16 . . . . . . . . . . . . . . . . . . . . 167
geoVISION825 81⁄4-in. Resistivity-at-the-Bit Tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-17 . . . . . . . . . . . . . . . . . . . . 168
arcVISION Array Resistivity Compensated Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-31 . . . . . . . . . . . . . . . . . . . . 169
arcVISION and ImPulse Array Resistivity Compensated Tools—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-32 . . . . . . . . . . . . . . . . . . . . 170
arcVISION Array Resistivity Compensated Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-33 . . . . . . . . . . . . . . . . . . . . 171
arcVISION and ImPulse Array Resistivity Compensated Tools—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-34 . . . . . . . . . . . . . . . . . . . . 172
arcVISION Array Resistivity Compensated Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-35 . . . . . . . . . . . . . . . . . . . . 173
arcVISION and ImPulse Array Resistivity Compensated Tools—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-36 . . . . . . . . . . . . . . . . . . . . 174
arcVISION675 Array Resistivity Compensated Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-37 . . . . . . . . . . . . . . . . . . . . 175
arcVISION675 and ImPulse Array Resistivity Compensated Tools—2 MHz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-38 . . . . . . . . . . . . . . . . . . . . 176
arcVISION Array Resistivity Compensated Tool—400 kHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-39 . . . . . . . . . . . . . . . . . . . . 177
arcVISION and ImPulse Array Resistivity Compensated Tools—2 MHz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-40 . . . . . . . . . . . . . . . . . . . . 178
arcVISION Array Resistivity Compensated Tool—400 kHz in Horizontal Well . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rt-41 . . . . . . . . . . . . . . . . . . . . 180
arcVISION and ImPulse Array Resistivity Compensated Tools—2 MHz in Horizontal Well . . . . . . . . . . . . . . . . . . . . . . . . . Rt-42 . . . . . . . . . . . . . . . . . . . . 181
Contents
viii
Lithology
Density and NGS* Natural Gamma Ray Spectrometry Tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-1 . . . . . . . . . . . . . . . . . . . 183
NGS Natural Gamma Ray Spectrometry Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-2 . . . . . . . . . . . . . . . . . . . 184
Platform Express* Three-Detector Lithology Density Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-3 . . . . . . . . . . . . . . . . . . . 186
Platform Express Three-Detector Lithology Density Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-4 . . . . . . . . . . . . . . . . . . . 187
Density Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-5 . . . . . . . . . . . . . . . . . . . 188
Density Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-6 . . . . . . . . . . . . . . . . . . . 190
Environmentally Corrected Neutron Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-7 . . . . . . . . . . . . . . . . . . . 192
Environmentally Corrected APS Curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-8 . . . . . . . . . . . . . . . . . . . 194
Bulk Density or Interval Transit Time and Apparent Total Porosity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-9 . . . . . . . . . . . . . . . . . . . 196
Bulk Density or Interval Transit Time and Apparent Total Porosity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-10 . . . . . . . . . . . . . . . . . . 197
Density Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-11 . . . . . . . . . . . . . . . . . . 199
Density Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lith-12 . . . . . . . . . . . . . . . . . . 200
Porosity
Sonic Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-1 . . . . . . . . . . . . . . . . . . . . 202
Sonic Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-2 . . . . . . . . . . . . . . . . . . . . 203
Density Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-3 . . . . . . . . . . . . . . . . . . . . 204
APS Near-to-Array (APLC) and Near-to-Far (FPLC) Logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-4 . . . . . . . . . . . . . . . . . . . . 206
Thermal Neutron Tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-5 . . . . . . . . . . . . . . . . . . . . 207
Thermal Neutron Tool—CNT-D and CNT-S 21⁄2-in. Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-6 . . . . . . . . . . . . . . . . . . . . 208
adnVISION475 4.75-in. Azimuthal Density Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-7 . . . . . . . . . . . . . . . . . . . . 209
adnVISION675 6.75-in. Azimuthal Density Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-8 . . . . . . . . . . . . . . . . . . . . 210
adnVISION825 8.25-in. Azimuthal Density Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-9 . . . . . . . . . . . . . . . . . . . . 211
CNL* Compensated Neutron Log and Litho-Density* Tool (fresh water in invaded zone) . . . . . . . . . . . . . . . . . . . . . . . . . . Por-11. . . . . . . . . . . . . . . . . . . 213
CNL Compensated Neutron Log and Litho-Density Tool (salt water in invaded zone) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-12. . . . . . . . . . . . . . . . . . . 214
APS and Litho-Density Tools. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-13. . . . . . . . . . . . . . . . . . . 215
APS and Litho-Density Tools (saltwater formation) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-14. . . . . . . . . . . . . . . . . . . 216
adnVISION475 4.75-in. Azimuthal Density Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-15. . . . . . . . . . . . . . . . . . . 217
adnVISION675 6.75-in. Azimuthal Density Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-16. . . . . . . . . . . . . . . . . . . 218
adnVISION825 8.25-in. Azimuthal Density Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-17. . . . . . . . . . . . . . . . . . . 219
Sonic and Thermal Neutron Crossplot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-20. . . . . . . . . . . . . . . . . . . 221
Sonic and Thermal Neutron Crossplot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-21. . . . . . . . . . . . . . . . . . . 222
Density and Sonic Crossplot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-22. . . . . . . . . . . . . . . . . . . 224
Density and Sonic Crossplot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-23. . . . . . . . . . . . . . . . . . . 225
Density and Neutron Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-24. . . . . . . . . . . . . . . . . . . 227
Density and APS Epithermal Neutron Tool. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-25. . . . . . . . . . . . . . . . . . . 229
Density, Neutron, and Rxo Logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-26. . . . . . . . . . . . . . . . . . . 231
Hydrocarbon Density Estimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Por-27. . . . . . . . . . . . . . . . . . . 232
Contents
ix
Saturation
Porosity Versus Formation Resistivity Factor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-1. . . . . . . . . . . . . . . . . 233
Spherical and Fracture Porosity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-2. . . . . . . . . . . . . . . . . 234
Saturation Determination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-3. . . . . . . . . . . . . . . . . 236
Saturation Determination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-4. . . . . . . . . . . . . . . . . 238
Graphical Determination of Sw from Swt and Swb. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-5. . . . . . . . . . . . . . . . . 239
Porosity and Gas Saturation in Empty Hole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-6. . . . . . . . . . . . . . . . . 240
EPT Propagation Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-7. . . . . . . . . . . . . . . . . 241
EPT Attenuation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatOH-8. . . . . . . . . . . . . . . . . 242
Capture Cross Section Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatCH-1 . . . . . . . . . . . . . . . . . 244
Capture Cross Section Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatCH-2 . . . . . . . . . . . . . . . . . 246
RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 6.125-in. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
RST Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 6.125-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatCH-3 . . . . . . . . . . . . . . . . . 248
RST Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 9.875-in. Borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SatCH-4 . . . . . . . . . . . . . . . . . 249
RST Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 8.125-in. Borehole with 4.5-in. Casing at 11.6 lbm/ft . . . . SatCH-5 . . . . . . . . . . . . . . . . . 250
RST Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 7.875-in. Borehole with 5.5-in. Casing at 17 lbm/ft . . . . . . SatCH-6 . . . . . . . . . . . . . . . . . 251
RST Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 8.5-in. Borehole with 7-in. Casing at 29 lbm/ft. . . . . . . . . . . SatCH-7 . . . . . . . . . . . . . . . . . 252
RST Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 9.875-in. Borehole with 7-in. Casing at 29 lbm/ft . . . . . . . . SatCH-8 . . . . . . . . . . . . . . . . . 253
Permeability
Permeability from Porosity and Water Saturation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Perm-1 . . . . . . . . . . . . . . . . . . 255
Permeability from Porosity and Water Saturation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Perm-2 . . . . . . . . . . . . . . . . . . 256
Fluid Mobility Effect on Stoneley Slowness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Perm-3 . . . . . . . . . . . . . . . . . . 257
Cement Evaluation
Cement Bond Log—Casing Strength. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cem-1 . . . . . . . . . . . . . . . . . . . 260
Appendixes
Appendix A Linear Grid. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 261
Log-Linear Grid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
Water Saturation Grid for Resistivity Versus Porosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
Appendix B Logging Tool Response in Sedimentary Minerals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
Appendix C Acoustic Characteristics of Common Formations and Fluids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
Appendix D Conversions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 268
Appendix E Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271
Appendix F Subscripts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
Appendix G Unit Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
Appendix H References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
Gen
General
Symbols Used in Log InterpretationGen-1
(former Gen-3)
1
dhHole
diameter
di
dj
h
∆rj
(Invasion diameters)
Adjacent bed
Zone of transition
or annulus
Flushed zone
Adjacent bed
(Bedthickness)
Mud
hmc
dh
Rm
Rs
Rs
Resistivity of the zoneResistivity of the water in the zoneWater saturation in the zone
Rmc
Mudcake
Rmf
Sxo
Rxo
Rw
Sw
Rt
Ri
Uninvadedzone
PurposeThis diagram presents the symbols and their descriptions and rela-tions as used in the charts. See Appendixes D and E for identifica-tion of the symbols.
DescriptionThe wellbore is shown traversing adjacent beds above and below thezone of interest. The symbols and descriptions provide a graphicalrepresentation of the location of the various symbols within the well-bore and formations.
© Schlumberger
General
2
Gen
Estimation of Formation Temperature with Depth
PurposeThis chart has a twofold purpose. First, a geothermal gradient can be assumed by entering the depth and a recorded temperature atthat depth. Second, for an assumed geothermal gradient, if the tem-perature is known at one depth in the well, the temperature atanother depth in the well can be determined.
DescriptionDepth is on the y-axis and has the shallowest at the top and thedeepest at the bottom. Both feet and meters are used, on the leftand right axes, respectively. Temperature is plotted on the x-axis,with Fahrenheit on the bottom and Celsius on the top of the chart.The annual mean surface temperature is also presented inFahrenheit and Celsius.
ExampleGiven: Bottomhole depth = 11,000 ft and bottomhole tempera-
ture = 200°F (annual mean surface temperature = 80°F).
Find: Temperature at 8,000 ft.
Answer: The intersection of 11,000 ft on the y-axis and 200°F on the x-axis is a geothermal gradient of approximately1.1°F/100 ft (Point A on the chart).
Move upward along an imaginary line parallel to the con-structed gradient lines until the depth line for 8,000 ft isintersected. This is Point B, for which the temperatureon the x-axis is approximately 167°F.
General
3
Gen
General
Estimation of Formation Temperature with DepthGen-2
(former Gen-6)
80 100 150 200 250 300 350 60 100 150 200 250 300 350
27 50 75 100 125 150 175
16 25 50 75 100 125 150 175
Temperature (°F)
Temperature (°C)
Temperature gradient conversions: 1°F/100 ft = 1.823°C/100 m 1°C/100 m = 0.5486°F/100 ft
Depth(thousands
of feet)
Depth(thousandsof meters)
Annual meansurface temperature
Annual meansurface temperature
5
10
15
20
25
1
2
3
4
5
6
7
8
0.6 0.8 1.0 1.2 1.4 1.6°F/100 ft
1.09 1.46 1.82 2.19 2.55 2.92°C/100 m
B
A
Geothermal gradient
© Schlumberger
General
4
Gen
Estimation of Rmf and RmcFluid Properties Gen-3
(former Gen-7)
PurposeDirect measurements of filtrate and mudcake samples are preferred.When these are not available, the mud filtrate resistivity (Rmf) andmudcake resistivity (Rmc) can be estimated with the following methods.
DescriptionMethod 1: Lowe and DunlapFor freshwater muds with measured values of mud resistivity (Rm)between 0.1 and 2.0 ohm-m at 75°F [24°C] and measured values ofmud density (ρm) (also called mud weight) in pounds per gallon:
Method 2: Overton and LipsonFor drilling muds with measured values of Rm between 0.1 and 10.0 ohm-m at 75°F [24°C] and the coefficient of mud (Km) given as a function of mud weight from the table:
ExampleGiven: Rm = 3.5 ohm-m at 75°F and mud weight = 12 lbm/gal
[1,440 kg/m3].
Find: Estimated values of Rmf and Rmc.
Answer: From the table, Km = 0.584.
Rmf = (0.584)(3.5)1.07 = 2.23 ohm-m at 75°F.
Rmc = 0.69(2.23)(3.5/2.23)2.65 = 5.07 ohm-m at 75°F.
log . = . .R
Rmf
mm
⎛
⎝⎜⎞
⎠⎟− ×( )0 396 0 0475 ρ
R K R
R RR
R
mf m m
mc mfm
mf
= ( )
= ( )⎛
⎝⎜⎞
⎠⎟
1 07
2 65
0 69
.
.
. .
Mud Weight
lbm/gal kg/m3 Km
10 1,200 0.84711 1,320 0.70812 1,440 0.58413 1,560 0.48814 1,680 0.41216 1,920 0.380
18 2,160 0.350
10 20 50 100 200 500 1,000 2,000 5,000 10,000 20,000 50,000 100,000 300,000
2.0
1.5
1.0
0.5
0
–0.5
2.0
1.0
0
Total solids concentration (ppm or mg/kg)
Multiplier
† Multipliers that do not vary appreciably for low concentrations (less than about 10,000 ppm) are shown at the left margin of the chart
Li (2.5)†
NH4 (1.9)†
Na and CI (1.0)
NO3 (0.55)†
Br (0.44)†
I (0.28)†
OH (5.5)†
Mg
Mg
K
K
Ca
Ca
CO3
CO3
SO4
SO4
HCO3
HCO3
General
5
Gen
PurposeThis chart is used to approximate the parts-per-million (ppm) con-centration of a sodium chloride (NaCl) solution for which the totalsolids concentration of the solution is known. Once the equivalentconcentration of the solution is known, the resistivity of the solutionfor a given temperature can be estimated with Chart Gen-6.
DescriptionThe x-axis of the semilog chart is scaled in total solids concentrationand the y-axis is the weighting multiplier. The curve set representsthe various multipliers for the solids typically in formation water.
ExampleGiven: Formation water sample with solids concentrations
of calcium (Ca) = 460 ppm, sulfate (SO4) = 1,400 ppm,and Na plus Cl = 19,000 ppm. Total solids concentration= 460 + 1,400 + 19,000 = 20,860 ppm.
Find: Equivalent NaCl solution in ppm.
Answer: Enter the x-axis at 20,860 ppm and read the multipliervalue for each of the solids curves from the y-axis: Ca = 0.81, SO4 = 0.45, and NaCl = 1.0. Multiply each concentration by its multiplier:
(460 × 0.81) + (1,400 × 0.45) + (19,000 × 1.0) = 20,000 ppm.
Equivalent NaCl Salinity of SaltsGen-4
(former Gen-8)
© Schlumberger
Gen
General
6
Concentration of NaCl SolutionsGen-5
° =°
−API141 5
131 5.
.sg at 60 F
g/L at77°F
ppm grains/galat 77°F °F/100 ft °C/100 ft °API
Oil GravityConcentrations of NaCl Solutions
Temperature GradientConversion
Specificgravity (sg) at 60°F
Density of NaClsolution at77°F [25°C]
0.15 150
200
300
400
500600
8001,000
1,500
2,000
3,000
4,000
5,0006,000
8,000
10,000
15,000
20,000
30,000
40,000
60,000
80,000
100,000
150,000
200,000250,000
101.00
1.005
1.01
1.02
1.03
1.041.051.061.071.081.091.101.121.141.161.181.20
1.0
1.5
2.0
2.5
3.0
0.60
0.62
0.64
0.66
0.68
0.70
0.72
0.74
0.76
0.780.800.820.840.860.880.900.920.940.960.981.001.021.041.061.08
3.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
100
90
80
70
60
50
40
30
20
10
0
1.8
1.9
2.0
12.515
20
2530
40
5060708090100125150
200
250300
400
5006007008009001,0001,2501,500
2,000
2,5003,000
4,0005,0006,0007,0008,0009,00010,00012,50015,00017,500
0.2
0.3
0.4
0.50.6
0.81.0
1.5
2
3
456
8
10
15
20
30
405060
80100125150
200250300
1°F/100 ft = 1.822°C/100 m1°C/100 m = 0.5488°F/100 ft
© Schlumberger
Gen
General
7
Resistivity of NaCl Water Solutions
PurposeThis chart has a twofold purpose. The first is to determine the resis-tivity of an equivalent NaCl concentration (from Chart Gen-4) at aspecific temperature. The second is to provide a transition of resis-tivity at a specific temperature to another temperature. The solutionresistivity value and temperature at which the value was determinedare used to approximate the NaCl ppm concentration.
DescriptionThe two-cycle log scale on the x-axis presents two temperaturescales for Fahrenheit and Celsius. Resistivity values are on the leftfour-cycle log scale y-axis. The NaCl concentration in ppm andgrains/gal at 75°F [24°C] is on the right y-axis. The conversion approximation equation for the temperature (T) effect on the resistivity (R) value at the top of the chart is valid only for thetemperature range of 68° to 212°F [20° to 100°C].
Example OneGiven: NaCl equivalent concentration = 20,000 ppm.
Temperature of concentration = 75°F.
Find: Resistivity of the solution.
Answer: Enter the ppm concentration on the y-axis and the tem-perature on the x-axis to locate their point of intersec-tion on the chart. The value of this point on the lefty-axis is 0.3 ohm-m at 75°F.
Example TwoGiven: Solution resistivity = 0.3 ohm-m at 75°F.
Find: Solution resistivity at 200°F [93°C].
Answer 1: Enter 0.3 ohm-m and 75°F and find their intersection on the 20,000-ppm concentration line. Follow the line tothe right to intersect the 200°F vertical line (interpolatebetween existing lines if necessary). The resistivity valuefor this point on the left y-axis is 0.115 ohm-m.
Answer 2: Resistivity at 200°F = resistivity at 75°F × [(75 + 6.77)/(200 + 6.77)] = 0.3 × (81.77/206.77) = 0.1186 ohm-m.
continued on next page
General
8
Gen
Resistivity of NaCl Water SolutionsGen-6
(former Gen-9)
°F 50 75 100 125 150 200 250 300 350 400°C 10 20 30 40 50 60 70 80 90 100 120 140 160 180 200
Temperature
Resistivityof solution(ohm-m)
ppm
10
8
6
5
4
3
2
1
0.8
0.60.5
0.4
0.3
0.2
0.1
0.08
0.060.05
0.04
0.03
0.02
0.01
200
300
400
5006007008001,0001,2001,4001,7002,000
3,0004,0005,0006,0007,0008,00010,00012,00014,00017,00020,000
30,00040,00050,00060,00070,00080,000100,000120,000140,000170,000200,000250,000280,000
Conversion approximated by R2 = R1 [(T1 + 6.77)/(T2 + 6.77)]°F or R2 = R1 [(T1 + 21.5) /(T2 + 21.5)]°C
300,000
NaClconcentration
(ppm orgrains/gal)
grains/galat 75°F
10
15
20
2530
40
50
100
150
200
250300
400
500
1,000
1,500
2,0002,5003,000
4,0005,000
10,000
15,00020,000
© Schlumberger
General
9
Gen
Density of Water and Hydrogen Index of Water and HydrocarbonsGen-7
PurposeThese charts are for determination of the density (g/cm3) and hydro-gen index of water for known values of temperature, pressure, andsalinity of the water. From a known hydrocarbon density of oil, adetermination of the hydrogen index of the oil can be obtained.
Description: Density of WaterTo obtain the density of the water, enter the desired temperature (°Fat the bottom x-axis or °C at the top) and intersect the pressure andsalinity in the chart. From that point read the density on the y-axis.
Example: Density of WaterGiven: Temperature = 200°F [93°C], pressure = 7,000 psi, and
salinity = 250,000 ppm.
Answer: Density of water = 1.15 g/cm3.
Example: Hydrogen Index of Salt WaterGiven: Salinity of saltwater = 125,000 ppm.
Answer: Hydrogen index = 0.95.
Example: Hydrogen Index of HydrocarbonsGiven: Oil density = 0.60 g/cm3.
Answer: Hydrocarbon index = approximately 0.91.
1.20
Pressure NaCl
14.7 psi1,000 psi7,000 psi
25 50 100
Temperature (°C)
Temperature (°F)
Hydrogen Index of Salt Water
Hydrogen Index of Live Hydrocarbons and Gas
Salinity (kppm or g/kg)
Hydrocarbon density (g/cm3)
150 200
0.85440400 30020010040
Hydrocarbons
Water
0.90
0.95
1.00
1.05
1.10
1.15
1.05
1.2
1.2
1.0
1.00
0
0.2
0.2
0.4
0.4
0.6
0.6
0.8
0.8
1.00
0.95
0.90
0.850 50 100 150 200 250
Water density (g/cm3)
Hydrogenindex
Hydrogenindex
250,000 ppm
200,000 ppm
150,000 ppm
100,000 ppm
50,000 ppm
Distilled water
© Schlumberger
General
10
Gen
PurposeThis chart can be used to determine more than one characteristic of natural gas under different conditions. The characteristics are gas density (ρg), gas pressure, and hydrogen index (Hgas).
DescriptionFor known values of gas density, pressure, and temperature, the valueof Hgas can be determined. If only the gas pressure and temperatureare known, then the gas density and Hgas can be determined. If thegas density and temperature are known, then the gas pressure andHgas can be determined.
ExampleGiven: Gas density = 0.2 g/cm3 and temperature = 200°F.
Find: Gas pressure and hydrogen index.
Answer: Gas pressure = approximately 5,200 psi and Hgas = 0.44.
Density and Hydrogen Index of Natural GasGen-8
0
0.1
0.2
0.3
0.4
0.5
100 200 400300
17,50015,00012,50010,000
7,500
5,000
2,500
Temperature (°F)
Pressure (psi)
Gas gravity = 0.65
Gas density (g/cm3)
Gas pressure × 1,000 (psia)
0
0.1
0.2
0.3 0.7
Hgas
Gastemperature
(°F)
Gas gravity = 0.6(Air = 1.0)
0.6 100
150200250300350
0.5
0.4
0.3
0.2
0.1
0 0 2 4 6 8 10
Gas density (g/cm3)
14.7
© Schlumberger
General
11
PurposeThis chart is used to determine the sound velocity (ft/s) and soundslowness (µs/ft) of gas in the formation. These values are helpful insonic and seismic interpretations.
DescriptionEnter the chart with the temperature (Celsius along the top x-axisand Fahrenheit along the bottom) to intersect the formation pore pressure.
Gen
General
Sound Velocity of HydrocarbonsGen-9
Gas gravity = 0.65
Natural Gas
50 100 150 200 250 300 3500
1,000
2,000
3,000
4,000
5,000 200
250
30017,500
15,000
12,500
10,000
7,500
5,000
2,500
14.7
400
500
1,000
2,000
Temperature (°C)
Pressure (psi)
Temperature (°F)
Soundvelocity
(ft /s)
Soundslowness
(µs/ft)
0 50 100 150 200
© Schlumberger
Gas Effect on Compressional Slowness
General
Gen-9a
12
Gen
PurposeThis chart illustrates the effect that gas in the formation has on theslowness time of sound from the sonic tool to anticipate the slownessof a formation that contains gas and liquid.
DescriptionEnter the chart with the compressional slowness time (∆tc) from thesonic log on the y-axis and the liquid saturation of the formation onthe x-axis. The curves are used to determine the gas effect on thebasis of which correlation (Wood’s law or Power law) is applied. Theslowing effect begins sooner for the Power law correlation. TheWood’s law correlation slightly increases ∆tc values as the formationliquid saturation increases whereas the Power law correlationdecreases ∆tc values from about 20% liquid saturation.
1000
200
100
200 µs/ft
110 µs/ft
90 µs/ft
70 µs/ft
50
∆tc(µs/ft)
Wetsand
Sandstone
80604020
Wood’s law (e = 5) Power law (e = 3)
Liquid saturation (%)
© Schlumberger
General
Gas Effect on Acoustic VelocitySandstone and Limestone Gen-9b
13
Limestone
Sandstone
0 10 20 30 40
25
00
5
10
10
15
20
20
25
30 40
20
15
10
5
0
Porosity (p.u.)
Porosity (p.u.)
Velocity(1,000 × ft /s)
Velocity(1,000 × ft /s) Vp
Vs
Vs
Vp
No gasGas bearing
No gasGas bearing
Gen
PurposeThis chart is used to determine porosity from the compressionalwave or shear wave velocity (Vp and Vs, respectively).
DescriptionEnter Vp or Vs on the y-axis to intersect the appropriate curve. Readthe porosity for the sandstone or limestone formation on the x-axis.
© Schlumberger
General
14
Gen
PurposeLongitudinal (Bulk) Relaxation Time of Pure WaterThis chart provides an approximation of the bulk relaxation time(T1) of pure water depending on the temperature of the water.
Transverse (Bulk and Diffusion) Relaxation Time of Water in the FormationDetermining the bulk and diffusion relaxation time (T2) from thischart requires knowledge of both the formation temperature and the echo spacing (TE) used to acquire the data. These data are pre-sented graphically on the log and are the basis of the water or hydrocarbon interpretation of the zone of interest.
DescriptionLongitudinal Relaxation TimeThe chart relation is for pure water—the additives in drilling fluidsreduce the relaxation time (T1) of water in the invaded zone. Thetwo major contributors to the reduction are surfactants added to thedrilling fluid and the molecular interactions of the mud filtrate con-tained in the pore spaces and matrix minerals of the formation.
Transverse Relaxation TimeThe relaxation time (T2) determination is based on the formationtemperature and echo spacing used to acquire the measurement.The TE value is listed in the parameter section of the log. Using the T2 measurement from a known water sand or based on localexperience further aids in determining whether a zone of interest contains hydrocarbons, water, or both.
Nuclear Magnetic Resonance Relaxation Times of WaterGen-10
Longitudinal (Bulk) RelaxationTime of Water
Temperature (°C)
Relaxationtime (s)
100
10
1.0
0.1
0.0120 60 100 140 180
T1
Transverse (Bulk and Diffusion) Relaxation Time of Water
Temperature (°C)
Relaxationtime (s)
100
10
1.0
0.1
0.0120 60 100 140 180
T2 (TE = 0.2 ms)
T2 (TE = 0.32 ms)
T2 (TE = 1 ms)
T2 (TE = 2 ms)
© Schlumberger
General
15
Gen
Nuclear Magnetic Resonance Relaxation Times of HydrocarbonsGen-11a
PurposeLongitudinal (Bulk) Relaxation Time of Crude OilThis chart is used to predict the T1 of crude oils with various viscosi-ties and densities or specific gravities to assist in interpretation ofthe fluid content of the formation of interest.
Transverse (Bulk and Diffusion) Relaxation TimeKnown values of T2 and TE can be used to approximate the viscosityby using this chart.
Diffusion Coefficients for Hydrocarbon and WaterThese charts are used to predict the diffusion coefficient of hydro-carbon as a function of formation temperature and viscosity and of water as a function of formation temperature.
DescriptionLongitudinal (Bulk) Relaxation TimeThis chart is divided into three distinct sections based on the compo-sition of the oil measured. The type of oil contained in the formationcan be determined from the measured T1 and viscosity determinedfrom the transverse relaxation time chart.
Transverse (Bulk and Diffusion) Relaxation TimeThe viscosity can be determined with values of the measured T2 andTE for input to the longitudinal relaxation time chart to identify thetype of oil in the formation.
Transverse (Bulk and Diffusion) Relaxation Time of Crude Oil
T1 (s)
Longitudinal (Bulk) Relaxation Time of Crude Oil
Viscosity (cp)
0.1 1 10 100 1,000 10,000 100,000
0.001
0.01
0.1
1
10
0.0001
T2 (s)
Viscosity (cp)
0.1 1 10 100 1,000 10,000 100,000
0.001
0.01
0.1
1
10
0.0001
Diffusion (cm2/s)
Hydrocarbon Diffusion Coefficient10–3
10–4
10–5
10–6
10–7
1500 50 100 200
Temperature (°C)
Oil (9° at 20°C)
Oil (40° at 20°C)
Diffusion (10–5 cm2/s)
Water Diffusion Coefficient
Temperature (°C)
0 50 100 150 2000
5
10
15
20
Light oil: 45°–60° API 0.65–0.75 g/cm3
Medium oil: 25°–40° API 0.75–0.85 g/cm3
Heavy oil: 10°–20° API 0.85–0.95 g/cm3
TE = 0.2 ms TE = 0.32 ms TE = 1 ms TE = 2 ms
T1
© Schlumberger
General
Nuclear Magnetic Resonance Relaxation Times of HydrocarbonsGen-11b
16
0 0.2 0.4 0.6 0.8 1.0 1.20
0.2
0.4
0.6
0.8
1.0
1.2
Hydrocarbon density (g/cm3)
Hydrogen index
Hydrogen Index of Live Hydrocarbons and Gas
0
2
4
6
0 6,000 9,000
25°C75°C125°C175°C
Longitudinal (Bulk) Relaxation Time of Methane
Pressure (psi)
3,000 12,000
10
8
Diffusion (cm2/s)
10–20.001
Transverse (Bulk and Diffusion) Relaxation Time of Methane
TE = 2 ms
100
10–4
0.01
0.1
1
10
10–3
T2 (s)
TE = 1 ms
TE = 0.32 ms
TE = 0.2 ms
T1 (s)
10
15
20
25
30
35
50 100 150 200
Methane Diffusion Coefficient
Diffusion (10–4 cm2/s)
Temperature (°C)
1,600 psi
3,000
00
5
8,300
15,500
22,800
3,900
4,500
00
Gen
General
PurposeMethane Diffusion CoefficientThis chart is used to determine the diffusion coefficient of methaneat a known formation temperature and pressure.
Longitudinal and Transverse Relaxation Times of MethaneThese charts are used to determine the longitudinal relaxation time(T1) of methane by using the formation temperature and pressure(see Reference 48) and the transverse relaxation time (T2) ofmethane by using the diffusion and echo spacing (TE), respectively.
Hydrogen Index of Live Hydrocarbons and GasThis chart is used to determine the hydrogen index from the hydro-carbon density.
© Schlumberger
General
Capture Cross Section of NaCl Water Solutions
17
GenPurposeThe sigma value (Σw) of a saltwater solution can be determined fromthis chart. The sigma water value is used to calculate the water satu-ration of a formation.
DescriptionCharts Gen-12 and Gen-13 define sigma water for pressure condi-tions of ambient through 20,000 psi [138 MPa] and temperaturesfrom 68° to 500°F [20° to 260°C]. Enter the appropriate chart forthe pressure value with the known water salinity on the y-axis andmove horizontally to intersect the formation temperature. The sigmaof the formation water for the intersection point is on the x-axis.
ExampleGiven: Water salinity = 125,000 ppm, temperature = 68°F at
ambient pressure, and formation temperature = 190°Fat 5,000 psi.
Find: Σw at ambient conditions and Σw of the formation.
Answer: Σw = 69 c.u. and Σw of the formation = 67 c.u.
If the sigma water apparent (Σwa) is known from a clean watersand, then the salinity of the formation can be determined by enter-ing the chart from the sigma water value on the x-axis to intersectthe pressure and temperature values.
continued on next page
General
18
Gen
Ambient
200°F
[93°C
]
68°F [
20°C]
400°F
[205°C
]
300°F
[150°C
]
200°F
[93°C
]
68°F [
20°C]
400°F
[205°C
]
300°F
[150°C
]
200°F
[93°C
]
68°F [
20°C]
1,000
psi [6.
9 MPa]
5,000
psi [34
MPa]
300
275
250
225
200
175
150
125
100
75
50
25
0
100
75
50
25
0
100
75
50
25
0
300
275
250
225
200
300
275
250
225
200
300
275
250
225
200
175
150
125
100
75
50
25
0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140
125
150
175175
150
125
Equivalent water salinity(1,000 × ppm NaCl)
Capture Cross Section of NaCl Water SolutionsGen-12
(former Tcor-2a)
© Schlumberger
General
Capture Cross Section of NaCl Water SolutionsGen-13
(former Tcor-2b)
19
Gen
10,00
0 psi
[69 M
Pa]500
°F [26
0°C]
400°F
[205°C
]
300°F
[150°C
]
200°F
[93°C
]
68°F [
20°C]
400°F
[205°C
]
300°F
[150°C
]
200°F
[93°C
]
68°F [
20°C]
400°F
[205°C
]
300°F
[150°C
]
200°F
[93°C
]
68°F [
20°C]
15,00
0 psi
[103 M
Pa]
20,00
0 psi
[138 M
Pa]
300
275
250
225
200
175
150
125
100
75
50
25
0
100
75
50
25
0
100
75
50
25
0
300
275
250
225
200
300
275
250
225
200
300
275
250
225
200
175
150
125
100
75
50
25
0 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140
Equivalent water salinity(1,000 × ppm NaCl)
125
150
175175
150
125
PurposeChart Gen-13 continues Chart Gen-12 at higher pressure values forthe determination of Σw of a saltwater solution.
© Schlumberger
PurposeSigma hydrocarbon (Σh) for gas or oil can be determined by usingthis chart. Sigma hydrocarbon is used to calculate the water satura-tion of a formation.
DescriptionOne set of charts is for measurement in metric units and the other is for measurements in “customary” oilfield units.
For gas, enter the background chart of a chart set with the reser-voir pressure and temperature. At that intersection point move leftto the y-axis and read the sigma of methane gas.
For oil, use the foreground chart and enter the solution gas/oilratio (GOR) of the oil on the x-axis. Move upward to intersect theappropriate API gravity curve for the oil. From this intersectionpoint, move horizontally left and read the sigma of the oil on the y-axis.
ExampleGiven: Reservoir pressure = 8,000 psi, reservoir temperature =
300°F, gravity of reservoir oil = 30°API, and solution GOR = 200.
Find: Sigma gas and sigma oil.
Answer: Sigma gas = 10 c.u. and sigma oil = 21.6 c.u.
General
20
Gen
Capture Cross Section of Hydrocarbons
General
21
Gen
Capture Cross Section of HydrocarbonsGen-14
(former Tcor-1)
20.0
17.5
15.0
12.5
10.0
7.5
5.0
2.5
0
68
125
200
300400500
Reservoir pressure (psia)
0 4,000 8,000 12,000 16,000 20,000
Methane
Temperature (°F)Σh (c.u.)
Customary
10 100 1,000 10,000
Solution GOR (ft3/bbl)
Liquid hydrocarbons
Condensate
30°, 40°, and 50°API
20° and 60°API
16
18
20
22
Σh (c.u.)
Metric
20.0
17.5
15.0
12.5
10.0
7.5
5.0
2.5
0
20
52
93
150
260
Reservoir pressure (mPa)
0 14 28 41 55 69 83 97 110 124 138
Methane
Temperature (°C)Σh (c.u.)
2 10 100 1,000 2,000
Solution GOR (m3/m3)
205
Condensate
Liquid hydrocarbons
0.78 to 0.88 mg/m3
0.74 or 0.94 mg/m3
16
18
20
22
Σh (c.u.)
© Schlumberger
General
EPT* Propagation Time of NaCl Water SolutionsGen-15
(former EPTcor-1)
22
PurposeThis chart is designed to determine the propagation time (tpw) ofsaltwater solutions. The value of tpw of a water zone is used to deter-mine the temperature variation of the salinity of the formation water.
DescriptionEnter the chart with the known salinity of the zone of interest andmove upward to the formation temperature curve. From that inter-section point move horizontally left and read the propagation time of the water in the formation on the y-axis. Conversely, enter thechart with a known value of tpw from the EPT ElectromagneticPropagation Tool log to intersect the formation temperature curveand read the water salinity at the bottom of the chart.
90
80
70
60
50
40
30
20 0 50 100 150 200 250
Equivalent water salinity (1,000 × ppm or g/kg NaCl)
tpw (ns/m)
120°C250°F
100°C200°F
80°C175°F
40°C100°F
150°F 60°C
75°F 20°C
125°F
Gen
*Mark of Schlumberger© Schlumberger
General
23
Gen
EPT* Attenuation of NaCl Water SolutionsGen-16
(former EPTcor-2)
PurposeThis chart is designed to estimate the attenuation of saltwater solu-tions. The attenuation (Aw) value of a water zone is used in conjunc-tion with the spreading loss determined from the EPT propagationtime measurement (tpl) to determine the saturation of the flushedzone by using Chart SatOH-8.
DescriptionEnter the chart with the known salinity of the zone of interest andmove upward to the formation temperature curve. From that intersec-tion point move horizontally left and read the attenuation of the waterin the formation on the y-axis. Conversely, enter the chart with a knownEATT attenuation value of Aw from the EPT ElectromagneticPropagation Tool log to intersect the formation temperature curveand read the water salinity at the bottom of the chart.
0 5 10 15 20 25 30
Uncorrected tpl (ns/m)
0 50 100 150 200 250
Equivalent water salinity (kppm or g/kg NaCl)
Correctionto EATT(dB/m)
–40
–60
–80
–100
–120
–140
–160
–180
–200
120°C250°F100°C200°F 80°C175°F
40°C100°F
150°F 60°C
75°F 20°C
125°F
5,000
4,000
3,000
2,000
1,000
0
Attenuation,Aw
(dB/m)
EPT-D Spreading Loss
*Mark of Schlumberger© Schlumberger
General
24
Gen
EPT* Propagation Time–Attenuation CrossplotSandstone Formation at 150°F [60°C] Gen-16a
PurposeThis chart is used to determine the apparent resistivity of the mudfiltrate (Rmfa) from measurements from the EPT ElectromagneticPropagation Tool. The porosity of the formation (φEPT) can also beestimated. Porosity and mud filtrate resistivity values are used indetermining the water saturation.
DescriptionEnter the chart with the known attenuation and propagation time(tpl). The intersection of those values identifies Rmfa and φEPT fromthe two sets of curves. This chart is characterized for a sandstoneformation at a temperature of 150°F [60°C].
ExampleGiven: Attenuation = 300 dB/m and tpl = 13 ns/m.
Find: Apparent resistivity of the mud filtrate and EPT porosity.
Answer: Rmfa = 0.1 ohm-m and φEPT = 20 p.u.
1,000
900
800
700
600
500
400
300
200
100
07 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
1.0
40 50302010
2.05.0
10.050.0
Attenuation(dB/m)
tpl (ns/m)
Sandstone at 150°F [60°C]
Rmfa from EPT log (ohm-m)
EPT
poro
sity (φ EP
T)
0.02 0.05
0.1
0.2
0.5
*Mark of Schlumberger© Schlumberger
Gamma Ray—Wireline
Scintillation Gamma Ray—33⁄8- and 111⁄16-in. ToolsGamma Ray Correction for Hole Size and Barite Mud Weight GR–1
(former GR-1)
25
PurposeThis chart provides a correction factor for measured values of forma-tion gamma ray (GR) in gAPI units. The corrected GR values can beused to determine shale volume corrections for calculating water saturation in shaly sands.
DescriptionThe semilog chart has the t factor on the x-axis and the correctionfactor on the y-axis.
The input parameter, t, in g/cm2, is calculated as follows:
where
Wmud = mud weight (lbm/gal)
dh = diameter of wellbore (in.)
dsonde = outside diameter (OD) of tool (in.).
ExampleGiven: GR = 36 API units (gAPI), dh = 12 in., mud weight =
12 lbm/gal, tool OD = 33⁄8 in., and the tool is centered.
Find: Corrected GR value.
Answer:
Enter the chart at 15.8 on the x-axis and move upward tointersect the 33⁄8-in. centered curve. The correspondingcorrection factor is 1.6.
1.6 × 36 gAPI = 58 gAPI.
10.0
7.0
5.0
3.0
2.0
1.0
0.7
0.5
0.3
Correction factor
t (g/cm2)
0 5 10 15 20 25 30 35 40
Scintillation Gamma Ray
33⁄8-in. tool, centered
111⁄16-in. tool, centered
33⁄8-in. tool, eccentered
111⁄16-in. tool, eccentered
GR
tW d dmud h sonde=
( )−
( )⎛
⎝⎜⎜
⎞
⎠⎟⎟8 345
2 54
2
2 54
2.
. .,
t =( )
−( )⎛
⎝⎜⎜
⎞
⎠⎟⎟
=128 345
2 54 12
2
2 54 3 375
215
.
. . ..88 2g cm/ .
© Schlumberger
PurposeThese charts are used to further correct the GR reading for variousborehole sizes.
DescriptionTwo components needed to complete correction of the GR readingare determined with these charts: barite mud factor (Bmud) andborehole function factor (Fbh).
Example Given: Borehole diameter = 6.0 in., tool OD = 33⁄8 in., the tool
is centered, mud weight = 12 lbm/gal, measured GR = 36 gAPI.
Find: Corrected GR value.
Answer: Enter the upper chart for Bmud versus mud weight at 12 lbm/gal on the x-axis. The intersection point with the33⁄8-in. centered curve is Bmud < 0.15 on the y-axis.
Determine (dh – dsonde) as 6 – 3.375 = 2.625 in. and enter
that value on the lower chart for Fbh versus (dh – dsonde) on the x-axis. Move upward to intersect the 33⁄8-in. curve, at which Fbh = 0.81.
Determine the new value of t using the equation fromChart GR-1:
The correction factor determined from Chart GR-1 is 0.95.
The complete correction factor is
(Chart GR-1 correction factor) × [1 + (Bmud × Fbh)]= 1.12 × [1 + (0.15 × 0.81)] = 1.26.
Corrected GR = 36 × 1.26 = 45.4 gAPI.
Gamma Ray—Wireline
Scintillation Gamma Ray—33⁄8- and 111⁄16-in. ToolsGamma Ray Correction for Barite Mud in Various-Size Boreholes GR-2
(former GR-2)
26
1.2
1.0
0.8
0.6
0.4
0.2
0
Mud weight (lbm/gal)
7 8 9 10 11 12 13 14 15 16 17 18 19 20
1.2
1.0
0.8
0.6
0.4
0.2
0
Fbh
0 1 2 3 4 5 6 7 8 9 10
dh – dsonde (in.)
Bmud
33⁄8-in. tool, centered
111⁄16-in. tool, centered
33⁄8-in. tool, eccentered
111⁄16-in. tool, eccentered
33⁄8-in. tool
111⁄16-in. tool
GR
tW d d
mud h sonde=( )
−( )⎛
⎝⎜⎜
⎞
⎠⎟⎟8 345
2 54
2
2 54
2.
. .
=( )
−( )⎛
⎝⎜⎜
⎞
⎠⎟⎟
=128 345
2 54 6
2
2 54 3 375
24 8
.
. . .. /g ccm2.
© Schlumberger
Gamma Ray—Wireline
Scintillation Gamma Ray—33⁄8- and 111⁄16-in. ToolsBorehole Correction for Cased Hole GR-3
(former GR-3)
27
PurposeThis chart is used to compensate for the effects of the casing,cement sheath, and borehole fluid on the GR count rate. The correc-tion brings the cased hole count rate in line with the measuredopenhole GR count rate.
DescriptionIn small boreholes the count rate can be too large, and in largerboreholes the count rate can be too small. The chart is based on lab-oratory work and Monte Carlo calculations to provide a correctionfactor for application to the measured GR count rate in cased holeenvironments.
ExampleGiven: GR = 19 gAPI, dh = 12 in., casing = 95⁄8 in. and
43.50 lbm/ft, tool OD = 33⁄8 in., and mud weight = 8.345 lbm/gal.
Find: Corrected GR value.
Answer:
Enter the chart at t = 10.95 on the x-axis. At the inter-section with the 33⁄8-in. curve, the value of the correctionfactor is 1.3.
The GR value is corrected by multiplying by the correction factor:19 gAPI × 1.3 = 24.7 gAPI.
10.0
7.0
5.0
3.0
2.0
1.0
0.7
0.5
0.3
Correction factor
0 5 10 15 20 25 30 35 40
Scintillation Gamma Ray
33⁄8-in. tool
111⁄16-in. tool
t (g/cm2)
GR
tW d d
mud h sonde=( )
−( )⎛
⎝⎜⎜
⎞
⎠⎟⎟8 345
2 54
2
2 54
2.
. .
=( )
−( )⎛
⎝⎜⎜
⎞
⎠⎟⎟
=8 3458 345
2 54 12
2
2 54 3 375
21
.
.
. . .00 95 2. / .g cm
© Schlumberger
PurposeThis chart is used to provide a correction factor for GR values measured with the SlimPulse third-generation slim measurements-while-drilling (MWD) tool or the E-Pulse electromagnetic telemetrytool. These environmental corrections for mud weight and bit sizeare already applied to the gamma ray presented on the logs. Thecorrected GR value is used in the water saturation equation to compensate for the shale in the formation.
DescriptionEnter the chart with the mud weight on the x-axis and moveupward to intersect the appropriate openhole size. Interpolatebetween lines as necessary. At the intersection point, move hori-zontally left to the y-axis to read the correction factor that theSlimPulse or E-Pulse GR value was multiplied by to obtain the corrected GR value in gAPI units.
Gamma Ray—LWD
SlimPulse* and E-Pulse* Gamma Ray ToolsBit Correction for Open Hole GR-6
28
11
10
9
8
7
6
5
4
3
2
1
0
Correction factor
Mud weight (lbm/gal)
8 9 10 11 12 13 14 15 16 17 18 19
6-in. bit7-in. bit
8.5-in. bit9.875-in. bit
12.25-in. bit
13.5-in. bit
17.5-in. bit
GR
*Mark of Schlumberger© Schlumberger
Gamma Ray—LWD
ImPulse* Gamma Ray— 4.75-in. ToolBit Correction for Open Hole GR-7
29
PurposeThis chart is used to provide a correction factor for GR values mea-sured with the ImPulse integrated MWD platform. These environ-mental corrections for mud weight and bit size are already appliedto the gamma ray presented on the logs. The corrected GR value isused in the water saturation equation to compensate for the shale in the formation.
DescriptionEnter the chart with the mud weight on the x-axis and moveupward to intersect the appropriate bit size. Interpolate betweenlines as necessary. At the intersection point, move horizontally leftto the y-axis to read the correction factor that the ImPulse GRvalue was multiplied by to obtain the corrected GR value in gAPI units.
1.75
1.50
1.25
1.00
0.75
Correction factor
Mud weight (lbm/gal)
8 9 10 11 12 13 14 15 16 17 18 19
8.5-in. bit
7-in. bit
6-in. bit
GR
*Mark of Schlumberger© Schlumberger
PurposeThis chart is used to provide a correction factor for GR values mea-sured with the PowerPulse 6.75-in. MWD telemetry system andTeleScope 6.75-in. high-speed telemetry-while-drilling service.These environmental corrections for mud weight and bit size arealready applied to the gamma ray presented on the logs. The cor-rected GR value is used in the water saturation equation to compen-sate for the shale in the formation.
DescriptionEnter the chart with the mud weight on the x-axis and move upwardto intersect the appropriate bit size. Interpolate between lines asnecessary. At the intersection point, move horizontally left to the y-axis to read the correction factor that the PowerPulse orTeleScope GR value was multiplied by to obtain the corrected GR value in gAPI units.
Gamma Ray—LWD
PowerPulse* and TeleScope* Gamma Ray—6.75-in. ToolsBit Correction for Open Hole GR-9
30
3.00
2.75
2.50
2.25
2.00
1.75
1.50
1.25
1.00
Correction factor
Mud weight (lbm/gal)
8 9 10 11 12 13 14 15 16 17 18 19
PowerPulse and TeleScope Gamma Ray
8.5 in.8.75 in.
10.625 in.
9.875 in.
12.25 in.
GR
*Mark of Schlumberger© Schlumberger
Gamma Ray—LWD
PowerPulse* Gamma Ray—8.25-in. Normal-Flow ToolBit Correction for Open Hole GR-10
31
PurposeThis chart is used to provide a correction factor for GR values mea-sured with the PowerPulse 8.25-in. normal-flow MWD telemetry system. These environmental corrections for mud weight and bitsize are already applied to the gamma ray presented on the logs.The corrected GR value is used in the water saturation equation to compensate for the shale in the formation.
DescriptionEnter the chart with the mud weight on the x-axis and move upwardto intersect the appropriate bit size. Interpolate between lines asnecessary. At the intersection point, move horizontally left to the y-axisto read the appropriate correction factor that the PowerPulse GR valuewas multiplied by to obtain the corrected GR value in gAPI units.
5.00
4.75
4.50
4.25
4.00
3.75
3.50
3.25
3.00
2.75
2.50
Correction factor
Mud weight (lbm/gal)
8 9 10 11 12 13 14 15 16 17 18 19
9.875-in. bit
12.25-in. bit
13.5-in. bit
17.5-in. bit
10.625-in. bit
14.75-in. bit
GR
*Mark of Schlumberger© Schlumberger
PurposeThis chart is used to provide a correction factor for GR values mea-sured with the PowerPulse 8.25-in. high-flow MWD telemetry system. These environmental corrections for mud weight and bitsize are already applied to the gamma ray presented on the logs.The corrected GR value is used in the water saturation equation to compensate for the shale in the formation.
DescriptionEnter the chart with the mud weight on the x-axis and move upwardto intersect the appropriate bit size. Interpolate between lines asnecessary. At the intersection point, move horizontally left to the y-axis to read the correction factor that the PowerPulse GR value was multiplied by to obtain the corrected GR value in gAPI units.
Gamma Ray—LWD
PowerPulse* Gamma Ray—8.25-in. High-Flow ToolBit Correction for Open Hole GR-11
32
4.25
4.00
3.75
3.50
3.25
3.00
2.75
2.50
2.25
2.00
1.75
Correction factor
Mud weight (lbm/gal)
8 9 10 11 12 13 14 15 16 17 18 19
17.5-in. bit
14.75-in. bit
13.5-in. bit
12.25-in. bit
10.625-in. bit
9.875-in. bit
GR
*Mark of Schlumberger© Schlumberger
Gamma Ray—LWD
PowerPulse* Gamma Ray—9-in. ToolBit Correction for Open Hole GR-12
33
PurposeThis chart is used to provide a correction factor for GR values measured with the PowerPulse 9-in. MWD telemetry system. Theseenvironmental corrections for mud weight and bit size are alreadyapplied to the gamma ray presented on the logs. The corrected GRvalue is used in the water saturation equation to compensate for theshale in the formation.
DescriptionEnter the chart with the mud weight on the x-axis and move upwardto intersect the appropriate bit size. Interpolate between lines asnecessary. At the intersection point, move horizontally left to the y-axis to read the correction factor that the PowerPulse GR valuewas multiplied by to obtain the corrected GR value in gAPI units.
7.50
7.00
6.50
6.00
5.50
5.00
4.50
4.00
3.50
3.00
2.50
Correction factor
Mud weight (lbm/gal)
8 9 10 11 12 13 14 15 16 17 18 19
17.5-in. bit
14.75-in. bit
13.5-in. bit
12.25-in. bit
10.625-in. bit
22-in. bit
GR
*Mark of Schlumberger© Schlumberger
PurposeThis chart is used to provide a correction factor for GR values measured with the PowerPulse 9.5-in. normal-flow MWD telemetrysystem. These environmental corrections for mud weight and bitsize are already applied to the gamma ray presented on the logs.The corrected GR value is used in the water saturation equation to compensate for the shale in the formation.
DescriptionEnter the chart with the mud weight on the x-axis and move upwardto intersect the appropriate bit size. Interpolate between lines asnecessary. At the intersection point, move horizontally left to the y-axis to read the correction factor that the PowerPulse GR value was multiplied by to obtain the corrected GR value in gAPI units.
Gamma Ray—LWD
PowerPulse* Gamma Ray—9.5-in. Normal-Flow ToolBit Correction for Open Hole GR-13
34
8.00
7.50
7.00
6.50
6.00
5.50
5.00
4.50
4.00
3.50
3.00
Correction factor
Mud weight (lbm/gal)
8 9 10 11 12 13 14 15 16 17 18 19
17.5-in. bit
14.75-in. bit
13.5-in. bit
12.25-in. bit
10.625-in. bit
22-in. bit
GR
*Mark of Schlumberger© Schlumberger
Gamma Ray—LWD
PowerPulse* Gamma Ray—9.5-in. High-Flow ToolBit Correction for Open Hole GR-14
35
PurposeThis chart is used to provide a correction factor for GR values mea-sured by the PowerPulse 9.5-in. high-flow MWD telemetry system.These environmental corrections for mud weight and bit size arealready applied to the gamma ray presented on the logs. The cor-rected GR value is used in the water saturation equation to compen-sate for the shale in the formation.
DescriptionEnter the chart with the mud weight on the x-axis and move upwardto intersect the appropriate bit size. Interpolate between lines asnecessary. At the intersection point, move horizontally left to the y-axis to read the correction factor that the PowerPulse GR valuewas multiplied by to obtain the corrected GR value in gAPI units.
8.00
7.50
7.00
6.50
6.00
5.50
5.00
4.50
4.00
3.50
3.00
2.50
2.00
Correction factor
Mud weight (lbm/gal)
8 9 10 11 12 13 14 15 16 17 18 19
10.625-in. bit
12.25-in. bit
13.5-in. bit
14.75-in. bit
17.5-in. bit
22-in. bitGR
*Mark of Schlumberger© Schlumberger
PurposeThis chart is used to provide a correction factor for GR values measured with the GVR resistivity sub of the geoVISION 63⁄4-in.MWD/LWD imaging system. These environmental corrections formud weight and bit size are already applied to the gamma ray pre-sented on the logs. The corrected GR value is used in the water sat-uration equation to compensate for the shale in the formation.
DescriptionEnter the chart with the mud weight on the x-axis and move upwardto intersect the appropriate bit size. Interpolate between lines asnecessary. At the intersection point, move horizontally left to the y-axis to read the correction factor that the GVR GR value was multi-plied by to obtain the corrected GR value in gAPI units.
Gamma Ray—LWD
geoVISION675* GVR* Gamma Ray—6.75-in. ToolBit Correction for Open Hole GR-15
36
2.75
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
Correction factor
Mud weight (lbm/gal)
8 9 10 11 12 13 14 15 16 17 18 19
8.5-in. bit8.75-in. bit
9.875-in. bit
10.625-in. bit
12.25-in. bit
GR
*Mark of Schlumberger© Schlumberger
Gamma Ray—LWD
RAB* Gamma Ray—8.25-in. ToolBit Correction for Open Hole GR-16
37
PurposeThis chart is used to provide a correction factor for GR values mea-sured with the RAB Resistivity-at-the-Bit 8.25-in. tool. These environ-mental corrections for mud weight and bit size are already appliedto the gamma ray presented on the logs. The corrected GR value isused in the water saturation equation to compensate for the shale in the formation.
DescriptionEnter the chart with the mud weight on the x-axis and move upward to intersect the appropriate bit size. Interpolate between lines asnecessary. At the intersection point, move horizontally left to the y-axis to read the correction factor that the RAB GR value was multiplied by to obtain the corrected GR value in gAPI units.
3.00
2.75
2.50
2.25
2.00
1.75
1.50
1.25
1.00
0.75
0.50
Correction factor
Mud weight (lbm/gal)
8 9 10 11 12 13 14 15 16 17 18 19
9.875-in. bit10.625-in. bit
12.25-in. bit
13.5-in. bit
14.75-in. bit
17.5-in. bit
GR
*Mark of Schlumberger© Schlumberger
PurposeThis chart is used to provide a correction factor for GR values mea-sured with the arcVISION475 43⁄4-in. drill collar resistivity tool.These environmental corrections for mud weight and bit size arealready applied to the gamma ray presented on the logs. The cor-rected GR value is used in the water saturation equation to compen-sate for the shale in the formation.
DescriptionEnter the chart with the mud weight on the x-axis and move upwardto intersect the appropriate bit size. Interpolate between lines asnecessary. At the intersection point, move horizontally left to the y-axis to read the correction factor that the arcVISION475 GR valuewas multiplied by to obtain the corrected GR value in gAPI units.
Gamma Ray—LWD
arcVISION475* Gamma Ray—4.75-in. ToolBit Correction for Open Hole GR-19
38
1.75
1.50
1.25
1.00
0.75
Correction factor
Mud weight (lbm/gal)
8 9 10 11 12 13 14 15 16 17 18 19
8.5-in. bit
7-in. bit
6-in. bit
GR
*Mark of Schlumberger© Schlumberger
Gamma Ray—LWD
arcVISION675* Gamma Ray—6.75-in. ToolBit Correction for Open Hole GR-20
39
PurposeThis chart is used to provide a correction factor for GR values mea-sured with the arcVISION675 63⁄4-in. drill collar resistivity tool.These environmental corrections for mud weight and bit size arealready applied to the gamma ray presented on the logs. The cor-rected GR value is used in the water saturation equation to compen-sate for the shale in the formation.
DescriptionEnter the chart with the mud weight on the x-axis and move upwardto intersect the appropriate bit size. Interpolate between lines asnecessary. At the intersection point, move horizontally left to the y-axis to read the appropriate correction factor that thearcVISION675 GR value was multiplied by to obtain the corrected GR value in gAPI units.
3.50
3.25
3.00
2.75
2.50
2.25
1.75
2.00
1.50
1.25
1.00
0.75
0.50
Correction factor
Mud weight (lbm/gal)
8 9 10 11 12 13 14 15 16 17 18 19
8.5-in. bit8.75-in. bit
9.875-in. bit
10.625-in. bit
12.25-in. bit
GR
*Mark of Schlumberger© Schlumberger
PurposeThis chart is used to provide a correction factor for GR values measured with the arcVISION825 81⁄4-in. drill collar resistivity tool.These environmental corrections for mud weight and bit size arealready applied to the gamma ray presented on the logs. The cor-rected GR value is used in the water saturation equation to compen-sate for the shale in the formation.
DescriptionEnter the chart with the mud weight on the x-axis and move upwardto intersect the appropriate bit size. Interpolate between lines asnecessary. At the intersection point, move horizontally left to they-axis and read the appropriate correction factor that thearcVISION825 GR value was multiplied by to obtain the corrected GR value in gAPI units.
Gamma Ray—LWD
arcVISION825* Gamma Ray—8.25-in. ToolBit Correction for Open Hole GR-21
40
3.00
2.75
2.50
2.25
2.00
1.50
1.75
1.25
1.00
0.75
0.50
Correction factor
Mud weight (lbm/gal)
8 9 10 11 12 13 14 15 16 17 18 19
9.875-in. bit
10.625-in. bit
12.25-in. bit
13.5-in. bit
14.75-in. bit
17.5-in. bit
GR
*Mark of Schlumberger© Schlumberger
Gamma Ray—LWD
arcVISION900* Gamma Ray—9-in. ToolBit Correction for Open Hole GR-22
41
PurposeThis chart is used to provide a correction factor for GR values measured with the arcVISION900 9-in. drill collar resistivity.These environmental corrections for mud weight and bit size arealready applied to the gamma ray presented on the logs. The cor-rected GR is used in the water saturation equation to compensatefor the shale in the formation.
DescriptionEnter the chart with the mud weight on the x-axis and move upwardto intersect the appropriate bit size. Interpolate between lines asnecessary. At the intersection point, move horizontally left to the y-axis and read the appropriate correction factor that thearcVISION900 GR value was multiplied by to obtain the corrected GR value in gAPI units.
5.5
5.0
4.5
4.0
3.5
2.5
3.0
2.0
1.5
1.0
0.5
Correction factor
Mud weight (lbm/gal)
8 9 10 11 12 13 14 15 16 17 18 19
10.625-in. bit12.25-in. bit
13.5-in. bit
14.75-in. bit
17.5-in. bit
22-in. bit
GR
*Mark of Schlumberger© Schlumberger
PurposeThis chart is used to provide a correction that is subtracted from the borehole-corrected gamma ray from the arcVISION475 43⁄4-in.tool. Environmental corrections for mud weight and bit size arealready applied to the gamma ray presented on the logs.
DescriptionThis chart is for illustrative purposes only. The indicated correctionis already applied to the gamma ray log.
To determine the correction that was applied to the log output,enter the chart with the borehole size on the x-axis and move upwardto intersect the downhole mud weight. From the intersection pointmove horizontally left to read the correction in gAPI units that wassubtracted from the borehole-corrected data.
Charts GR-24 through GR-26 are similar to Chart GR-23 for different arcVISION tool sizes.
Gamma Ray—LWD
arcVISION475* Gamma Ray—4.75-in. ToolPotassium Correction for Open Hole GR-23
42
100
90
80
70
60
40
50
30
20
10
6 8 10 12 14 16 180
Correctionsubtracted for 5-wt% potassium
(gAPI)
Hole size (in.)
8.3 ppg
9 ppg10 ppg
12 ppg14 ppg
16 ppg18 ppg
20 ppg
GR
*Mark of Schlumberger© Schlumberger
Gamma Ray—LWD
arcVISION675* Gamma Ray—6.75-in. ToolPotassium Correction for Open Hole GR-24
43
PurposeThis chart is used to provide a correction that is subtracted from the borehole-corrected gamma ray from the arcVISION675 63⁄4-in.tool. Environmental corrections for mud weight and bit size arealready applied to the gamma ray presented on the logs.
DescriptionThis chart is for illustrative purposes only. The indicated correctionis already applied on the gamma ray log.
To determine the correction that was applied to the log output,enter the chart with the borehole size on the x-axis and moveupward to intersect the downhole mud weight. From the intersectionpoint move horizontally left to read the correction in gAPI units thatwas subtracted from the borehole-corrected data.
50
45
40
35
30
20
25
15
10
5
0
Correctionsubtracted for 5-wt%potassium
(gAPI)
Hole size (in.)
8.5 9.0 9.5 10.0 10.5 11.0 11.5 12.0 13.012.5
9 ppg
8.3 ppg
10 ppg
12 ppg
14 ppg
16 ppg
18 ppg
20 ppg
GR
*Mark of Schlumberger© Schlumberger
PurposeThis chart is used to provide a correction that is subtracted from the borehole-corrected gamma ray from the arcVISION825 81⁄4-in.tool. Environmental corrections for mud weight and bit size arealready applied to the gamma ray presented on the logs.
DescriptionThis chart is for illustrative purposes only. The indicated correctionis already applied on the gamma ray log.
To determine the correction that was applied to the log output,enter the chart with the borehole size on the x-axis and move upwardto intersect the downhole mud weight. From the intersection pointmove horizontally left to read the correction in gAPI units that wassubtracted from the borehole-corrected data.
Gamma Ray—LWD
arcVISION825* Gamma Ray—8.25-in. ToolPotassium Correction for Open Hole GR-25
44
100
90
80
70
60
40
50
30
20
10
0
Correction subtracted for 5-wt%potassium
(gAPI)
Hole size (in.)
0 10 12 14 16 18 2220
10 ppg
9 ppg
8.3 ppg
12 ppg
14 ppg
16 ppg
18 ppg
20 ppg
GR
*Mark of Schlumberger© Schlumberger
Gamma Ray—LWD
arcVISION900* Gamma Ray—9-in. toolPotassium Correction for Open Hole GR-26
45
PurposeThis chart is used to provide a correction that is subtracted from the borehole-corrected gamma ray from the arcVISION900 9-in. tool.Environmental corrections for mud weight and bit size are alreadyapplied to the gamma ray presented on the logs.
DescriptionThis chart is for illustrative purposes only. The indicated correctionis already applied on the gamma ray log.
To determine the correction that was applied to the log output,enter the chart with the borehole size on the x-axis and move upwardto intersect the downhole mud weight. From the intersection pointmove horizontally left to read the correction curve in gAPI units thatwas subtracted from the borehole-corrected data.
120
100
80
60
40
20
0
Correction subtracted for 5-wt% potassium
(gAPI)
Hole size (in.)
109 1211 1413 15 1716 2018 19
10 ppg
9 ppg
8.3 ppg
12 ppg
14 ppg
16 ppg
18 ppg
20 ppg
GR
*Mark of Schlumberger© Schlumberger
Spontaneous Potential—Wireline
46
SP
Rweq Determination from ESSP
PurposeThis chart and nomograph are used to calculate the equivalent for-mation water resistivity (Rweq) from the static spontaneous potential(ESSP) measured in clean formations. The value of Rweq is used inChart SP-2 to determine the resistivity of the formation water (Rw).Rw is used in Archie’s water saturation equation.
DescriptionEnter the chart with ESSP in millivolts on the x-axis and moveupward to intersect the appropriate temperature line. From theintersection point move horizontally to intersect the right y-axis forRmfeq/Rweq. From this point, draw a straight line through the equiva-lent mud filtrate resistivity (Rmfeq) point on the Rmfeq nomograph tointersect the value of Rweq on the far-right nomograph.
The spontaneous potential (SP) reading corrected for the effectof bed thickness (ESPcor) from Chart SP-4 can be substituted for ESSP.
ExampleFirst determine the value of Rmfeq:
If Rmf at 75°F is greater than 0.1 ohm-m, correct Rmf
to the formation temperature by using Chart Gen-6, and use Rmfeq = 0.85Rmf.
If Rmf at 75°F is less than 0.1 ohm-m, use Chart SP-2 to derive a value of Rmfeq at formation temperature.
Given: ESSP = –100 mV at 250°F and resistivity of the mud filtrate (Rmf) = 0.7 ohm-m at 100°F, converted to 0.33 at 250°F.
Find: Rweq at 250°F.
Answer: Rmfeq = 0.85Rmf = 0.85 × 0.33 = 0.28 ohm-m.
Draw a straight line from the point on the Rmfeq/Rweq linethat corresponds to the intersection of ESSP = –100 mVand the interpolated 250°F temperature curve throughthe value of 0.28 ohm-m on the Rmfeq line to the Rweq lineto determine that the value of Rweq is 0.025 ohm-m.
The value of Rmfeq/Rweq can also be determined from theequation
ESSP = Kc log (Rmfeq/Rweq),
where Kc is the electrochemical spontaneous potentialcoefficient:
Kc = 61 + (0.133 × Temp°F)
Kc = 65 + (0.24 × Temp°C).
Spontaneous Potential—Wireline
47
SP
Rweq Determination from ESSPSP-1
(former SP-1)
0.01
0.02
0.040.06
0.1
0.2
0.4
0.6
1
2
4
6
10
20
40
60
100
0.001
0.005
0.01
0.02
0.05
0.1
0.2
0.5
1.0
2.0
Rmfeq(ohm-m)
Rmfeq/Rweq
Rmf /Rw
Rweq(ohm-m)
+50 0 –50 –100 –150 –200
Static spontaneous potential, ESSP (mV)
250°C200°C150°C
100°C
50°C0°C
500°F400°F300°F
200°F
Formationtemperature
0.3
0.4
0.6
0.8
1
2
4
6
8
10
20
40
0.3
0.4
0.50.6
0.8
1
2
3
4
6
8
10
20
30
40
50
5
100°F
© Schlumberger
PurposeThis chart is used to convert equivalent water resistivity (Rweq) fromChart SP-1 to actual water resistivity (Rw). It can also be used to con-vert the mud filtrate resistivity (Rmf) to the equivalent mud filtrateresistivity (Rmfeq) in saline mud. The metric version of this chart isChart SP-3 on page 49.
DescriptionThe solid lines are used for predominantly NaCl waters. The dashedlines are approximations for “average” fresh formation waters (forwhich the effects of salts other than NaCl become significant).
The dashed lines can also be used for gypsum-base mud filtrates.
ExampleGiven: From Chart SP-1, Rweq = 0.025 ohm-m at 250°F in
predominantly NaCl water.
Find: Rw at 250°F.
Answer: Enter the chart at the Rweq value on the y-axis and movehorizontally right to intersect the solid 250°F line. Fromthe intersection point, move down to find the Rw valueon the x-axis. Rw = 0.03 ohm-m at 250°F.
Rweq versus Rw and Formation TemperatureSP-2
(customary, former SP-2)
0.005 0.01 0.02 0.03 0.05 0.1 0.2 0.3 0.5 1.0 2 3 4 5
0.001
0.002
0.005
0.01
0.02
0.05
0.1
0.2
0.5
1.0
2.0
Rw or Rmf (ohm-m)
Rweq or Rmfeq
(ohm-m)
500°F400°F
300°F
200°F
150°F
100°F
75°F
Saturation
400°F300°F200°F150°F100°F75°F
500°F
NaCl at 75°F
Spontaneous Potential—Wireline
48
SP
© Schlumberger
Spontaneous Potential—WirelineSpontaneous Potential—Wireline
49
SP
Rweq versus Rw and Formation TemperatureSP-3
(metric, former SP-2m)
PurposeThis chart is the metric version of Chart SP-2 for converting equiva-lent water resistivity (Rweq) from Chart SP-1 to actual water resistiv-ity (Rw). It can also be used to convert the mud filtrate resistivity (Rmf)to the equivalent mud filtrate resistivity (Rmfeq) in saline mud.
DescriptionThe solid lines are used for predominantly NaCl waters. The dashedlines are approximations for “average” fresh formation waters
(for which the effects of salts other than NaCl become significant).The dashed lines can also be used for gypsum-base mud filtrates.
ExampleGiven: From Chart SP-1, Rweq = 0.025 ohm-m at 121°C in
predominantly NaCl water.
Find: Rw at 121°C.
Answer: Rw = 0.03 ohm-m at 121°C.
0.005 0.01 0.02 0.03 0.05 0.1 0.2 0.3 0.5 1.0 2 3 4 5
0.001
0.002
0.005
0.01
0.02
0.05
0.1
0.2
0.5
1.0
2.0
Rw or Rmf (ohm-m)
Rweq or Rmfeq
(ohm-m)
250°C200°C
150°C
100°C
75°C
50°C
25°C
Saturation
200°C150°C100°C75°C50°C25°C
250°C
NaCl at 25°C
© Schlumberger
Bed Thickness Correction—Open Hole
Spontaneous Potential—Wireline
50
SP
PurposeChart SP-4 is used to correct the SP reading from the well log for the effect of bed thickness. Generally, water sands greater than 20 ft in thickness require no or only a small correction.
DescriptionChart SP-4 incorporates correction factors for a number of condi-tions that can affect the value of the SP in water sands.
The appropriate chart is selected on the basis of resistivity, inva-sion, hole diameter, and bed thickness. First, select the row of chartswith the most appropriate value of the ratio of the resistivity of shale(Rs) to the resistivity of mud (Rm). On that row, select a chart for noinvasion or for invasion for which the ratio of the diameter of invasion to the diameter of the wellbore (di/dh) is 5. Enter the x-axis with the value of the ratio of bed thickness to wellbore diameter (h/dh).Move upward to intersect the appropriate curve of the ratio of thetrue formation resistivity to the resistivity of the mud (Rt /Rm) forno invasion or the ratio of the resistivity of the flushed zone to theresistivity of the mud (Rxo /Rm) for invaded zones, interpolatingbetween the curves as necessary. Read the ratio of the SP read fromthe log to the corrected SP (ESP/ESPcor) on the y-axis for the point ofintersection. Calculate ESPcor = ESP/(ESP/ESPcor). The value of ESPcor
can be used in Chart SP-1 for ESSP.
Spontaneous Potential-Wireline
51
SP
Spontaneous Potential—Wireline
Bed Thickness Correction—Open HoleSP-4
(former SP-3)
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
40 30 20 15 10 7.5 5
1.0
0.8
0.6
0.4
0.2
ESP/ESPcor
ESP/ESPcor
ESP/ESPcor
Rs
Rm= 1
Rs
Rm= 5
Rs
Rm= 20
Rxo = 0.2Rt Rxo = Rt
h/dh h/dh
h/dh h/dh h/dh
h/dh h/dh
Rxo = 5Rt
Invasion, di/dh = 5No Invasion
105 2
20
50
100
200
500
105 2
20
50
100
200
5001,000
10
5
21
20
50
100200500
10
52 1
20
50
100
200
5001,000
105 2
20
50
100
200
5001,000
10
5
210.5
20
50
100
200500
10
52
1
20
50
100
200
500
10
5
210.5
20
50
100
200
10
52 10.5
20
50
100
200Rxo/Rm Rxo/Rm Rxo/Rm
Rxo/Rm Rxo/Rm Rxo/Rm
Rxo/Rm Rxo/Rm Rxo/Rm
Rt/Rm
Rt/Rm
Rt/Rm
21
1
2
50
1020
5
0.5
0.2
0.1
100
10
20
50
100
200
5
10
5
2
1
0.5
0.2
20
50100200
h/dh h/dh
h/dh
h/dh h/dh
© Schlumberger
Bed Thickness Correction—Open Hole (Empirical)SP-5
(customary, former SP-4)
PurposeThis chart is used to provide an empirical correction to the SP for the effects of invasion and bed thickness. The correction was obtainedby averaging a series of thin-bed corrections in Reference 4. Theresulting value of static spontaneous potential (ESSP) can be used in Chart SP-1.
DescriptionThis chart considers bed thickness (h) as a variable, and the ratio ofthe resistivity of the invaded zone to the resistivity of the mud (Ri/Rm)and the diameter of invasion (di) as parameters of fixed value. Theborehole diameter is fixed at 8 in. and the tool size at 33⁄8 in.
To obtain the correction factor, enter the chart on the x-axis withthe value of h. Move upward to the appropriate di curve for the range of Ri/Rm. The correction factor on the y-axis corresponding to theintersection point is multiplied by the SP from the log to obtain thecorrected SP.
Spontaneous Potential—Wireline
52
70 50 40 30 20 15 10 9 8 7 6 5 4 3
Bed thickness, h (ft)
ESSP
(%)Correction
factor
1.0
1.5
2.0
2.5
3.0
3.5
4.0
5.0
5
20
50
100
200
di (in.)
30
3535
4040
3030
3030
20
8-in. Hole; 33⁄8-in. Tool, Centered
Ri
Rm
100
90
80
70
60
50
40
30
20
SP
© Schlumberger
Spontaneous Potential—WirelineSpontaneous Potential—Wireline
53
SP
PurposeThis chart is the metric version of Chart SP-5 for providing an empir-ical correction to the SP for the effects of invasion and bed thick-ness. The correction was obtained by averaging a series of thin-bedcorrections in Reference 4. The resulting value of ESSP can be usedin Chart SP-1.
DescriptionThis chart considers bed thickness (h) as a variable, and Ri/Rm and di as parameters of fixed value. The borehole diameter is fixed at 203 mm and the tool size at 86 mm.
Bed Thickness Correction—Open Hole (Empirical)SP-6
(metric, former SP-4m)
0.5
200-mm Hole; 86-mm Tool, Centered
Bed thickness, h (m)
ESSP
(%)Correction
factor
100
90
80
70
60
50
40
30
20
1.0
20 15 10 5 3 2 1
1.5
2.020
5
50
100
200
2.5
3.0
3.54.0
5.0
di (m)
Ri
Rm
0.75
0.750.75
0.750.75
0.80.881.0
1.0
© Schlumberger
54
1 2 3
Quartz Dolomite Calcite
GasWater
4 5 0.5 0.4 0.3 0.2 0.1 06
Pe φtPorosity Effect on Pe
Matrix φ t 100% H2O 100% CH4
Quartz0.00 1.81 1.810.35 1.54 1.76
Calcite0.00 5.08 5.080.35 4.23 4.96
Dolomite0.00 3.14 3.140.35 2.66 3.07
Specific — 1.00 0.10gravity
General
Porosity Effect on Photoelectric Cross SectionDens-1
PurposeThis chart and accompanying table illustrate the effect that porosity,matrix, formation water, and methane (CH4) have on the recordedphotoelectric cross section (Pe).
DescriptionThe table lists the data from which the chart was made. As theporosity increases the effect is greater for each mineral. Calcite hasthe largest effect in the presence of gas or water as the porosityincreases.
Enter the chart with the total porosity (φt) from the log and movedownward to intersect the angled line. From this point move to the left and intersect the line representing the appropriate matrixmaterial: quartz, dolomite, or calcite minerals. From this intersectionmove upward to read the correct Pe.
Density—Wireline, LWD
Dens
© Schlumberger
55
Dens
PurposeThis chart is used to determine the true bulk density (ρb) from the“apparent” recorded log value (ρlog).
DescriptionEnter the chart with the log density reading on the x-axis and moveupward to intersect the mineral line that best represents the forma-tion. At this point, move horizontally left to read the value to be addedto the log density. The individual mineral points reflect the log-deriveddensity and the correction factor to be added or subtracted from thelog value to obtain the true density of that mineral.
The long diagonal lines representing zero porosity at the lowerright and 40% porosity at the upper left are for dry gas in the forma-tion. The three points at the lower right of the diagonal lines rep-resent zero dry gas in the formation and are the endpoints for
sandstone, limestone, and dolomite with water in the pores. Thisshows that there is a slight correction for water-filled formationsfrom the log density value.
ExampleGiven: Log density = 2.40 g/cm3 in a sandstone formation
(dry gas).
Find: Corrected bulk density.
Answer: Enter the x-axis at 2.4 g/cm3 and move upward to inter-sect the sandstone line. The correction from the y-axis is0.02 g/cm3. The correction value is added to the log den-sity to obtain the true value of the bulk density:
2.40 + 0.02 = 2.42 g/cm3.
Density—Wireline, LWD
Apparent Log Density to True Bulk DensityDens-2
Magnesium
Dolomite
Sandstone + water
Low-pressure gasor air in pores
Sandstone
Sylvite (KCI)
Aluminum
Salt (NaCI)Add correction
from y-axis to ρlog
to obtain truebulk density, ρb
0.14
0.12
0.10
0.08
0.06
0.04
0.02
–0.02
–0.04
1 2 3
0
ρlog (g/cm3)
ρb – ρlog (g/cm3)
φ = 40%
φ = 0
φ = 40%
Limestone
AnthraciteCoalBituminous
Gypsum
Limestone + waterDolomite + water
© Schlumberger
56
Neu
Neutron—Wireline
Dual-Spacing Compensated Neutron Tool Charts
This section contains interpretation charts to cover developments incompensated neutron tool (CNT) porosity transforms, environmentalcorrections, and porosity and lithology determination.
CSU* software (versions CP-30 and later) and MAXIS* softwarecompute three thermal porosities: NPHI, TNPH, and NPOR.
NPHI is the “classic NPHI,” computed from instantaneous nearand far count rates, using “Mod-8” ratio-to-porosity transform with a caliper correction.
TNPH is computed from deadtime-corrected, depth- andresolution-matched count rates, using an improved ratio-to-porositytransform and performing a complete set of environmental correctionsin real time. These corrections may be turned on or off by the fieldengineer at the wellsite. For more information see Reference 32.
NPOR is computed from the near-detector count rate and TNPHto give an enhanced resolution porosity. The accuracy of NPOR isequivalent to the accuracy of TNPH if the environmental effects onthe near detector change less rapidly than the formation porosity.For more information on enhanced resolution processing, seeReference 35.
Cased hole CNT logs are recorded on NPHI, computed frominstantaneous near and far count rates, with a cased hole ratio-to-porosity transform.
Using the Neutron Correction ChartsFor logs labeled NPHI:1. Enter Chart Neu-5 with NPHI and caliper reading to convert to
uncorrected neutron porosity.
2. Enter Charts Neu-1 and Neu-3 to obtain corrections for eachenvironmental effect. Corrections are summed with the uncor-rected porosity to give a corrected value.
3. Use crossplot Charts Por-11 and Por-12 for porosity and lithologydetermination.
For logs labeled TNPH or NPOR, the CSU wellsite surface instru-mentation and MAXIS software have applied environmental correc-tions as indicated on the log heading. If the CSU and MAXISsoftware has applied all corrections, TNPH or NPOR can be useddirectly with the crossplot charts. In this case:
1. Use crossplot Charts Por-11 and Por-12 to determine porosityand lithology.
continued on next page
57
Neutron—Wireline
Neu
Compensated Neutron ToolEnvironmental Correction—Open Hole
PurposeChart Neu-1 is used to correct the compensated neutron log porosityindex if the caliper correction was not applied. If the caliper correc-tion is applied, it must be “backed out” to use this chart.
DescriptionThis chart is used only if the caliper correction was not applied to the logged data. The parameter section of the log heading listswhether correction was applied.
Example 1: Backed-Out Correction of TNPH PorosityGiven: Thermal neutron porosity (TNPH) from the log = 32 p.u.
(apparent limestone units) and borehole size = 12 in.
Find: Uncorrected TNPH with the correction backed out.
Answer: Enter the top chart for actual borehole size at the inter-section point of the standard conditions 8-in. horizontalline and 32 p.u. on the scale above the chart.
From this point, follow the closest trend line to intersectthe 12-in. line for the borehole size.
The intersection is the uncorrected TNPH value of 34 p.u.
To use the uncorrected value on Chart Neu-1, draw a ver-tical line from this intersection through the remainder ofthe charts, as shown by the red line.
Example 2: Environmentally Corrected THPHGiven: Neutron porosity of 32 p.u. (apparent limestone units),
without environmental correction, 12-in. borehole, 1⁄4-in.thick mudcake, 100,000-ppm borehole salinity, 11-lbm/galnatural mud weight (water-base mud [WBM]), 150°Fborehole temperature, 5,000-psi pressure (WBM), and100,000-ppm formation salinity.
Find: Environmentally corrected TNPH porosity.
Answer: If there is standoff (which is not uncommon), use ChartNeu-3. Then use Chart Neu-1 by drawing a vertical linethrough the charts for the previously determinedbacked-out (uncorrected) 34-p.u. neutron porosityvalue.
On each environmental correction chart, enter the y-axisat the given value and move horizontally left to intersectthe porosity value vertical line.
For example, on the mudcake thickness chart the lineextends from 1⁄4 in. on the y-axis.
At the intersection point, move parallel to the closestblue trend line to intersect the standard conditions, asindicated by the bullet.
The point of intersection with the standard conditionsfor the chart is the value of porosity corrected for theparticular environment. The change in porosity value(either positive or negative) is summed for the chartsand referred to as delta porosity (∆φ).
The ∆φ net correction applied to the uncorrected log neutronporosity is listed in the table for the two examples.
CNT Neutron Porosity Correction Examples
Correction
Example 1 Example 2 ∆φ
Log porosity 32 p.u.Borehole size 12 in. –2Mudcake thickness 1⁄4 in. 0Borehole salinity 100,000 ppm +1Mud weight 11 lbm/gal +2Borehole temperature 150°F +4Wellbore pressure 5,000 psi –1Formation salinity 100,000 ppm –3Standoff (from Chart Neu-3) 1 in. –4Net environmental correction –1Backed-out corrected porosity 34 p.u.Environmentally corrected porosity 33 p.u.Net correction –3Backed-out, environmentally corrected porosity 31 p.u.
RInd
Neutron—Wireline
Compensated Neutron ToolEnvironmental Correction—Open Hole Neu-1
(customary, former Por-14c)
0 10 20 30 40 50
0 10 20 30 40 50
• Standard conditions
Actual borehole size(in.)
1.0
0.5
0
Mudcake thickness(in.)
250
0
Borehole salinity(1,000 × ppm)
Mud weight(lbm/gal)
Natural
300
50
Borehole temperature(°F)
25
0
Pressure(1,000 × psi)
18161412108
Barite
Water-base mudOil-base mud
250
0
Limestoneformation salinity
(1,000 × ppm)
Neutron log porosity index (apparent limestone porosity in p.u.)
2420161284 •
•
•
•
•
•
•
•
1312111098
© Schlumberger
58
59
Neu
Neutron—Wireline
PurposeThis chart is the metric version of Chart Neu-1 for correcting thecompensated neutron tool porosity index.
Compensated Neutron ToolEnvironmental Correction—Open Hole Neu-2
(metric, former Por-14cm)
0 10 20 30 40 50
0 10 20 30 40 50
600500400300200100
Actual borehole size(mm)
25
12.5
0
Mudcake thickness(mm)
250
0
Borehole salinity(g/kg)
14912193663810
Borehole temperature(°C)
250
0
Limestoneformation salinity
(g/kg)
17213810369340
Pressure(MPa)
Water-base mudOil-base mud
1.5
1.0Mud density(g/cm3)
Nat
ural
2.0
1.0
Barit
e
• Standard conditions
Neutron log porosity index (apparent limestone porosity)
•
•
•
•
•
•
•
•
© Schlumberger
Neutron—Wireline
60
Neu
PurposeChart Neu-3 is used to determine the porosity change caused bystandoff to the uncorrected thermal neutron porosity TNPH fromChart Neu-1.
DescriptionEnter the appropriate borehole size chart at the estimated neutrontool standoff on the y-axis. Move horizontally to intersect the uncor-rected porosity. At the intersection point, move along the closesttrend line to the standard conditions line defined by the bullet to the right of the chart. This point is the porosity value corrected fortool standoff. The difference between the standoff-corrected porosityand the uncorrected porosity is the correction itself.
ExampleGiven: TNPH = 34 p.u., borehole size = 12 in., and
standoff = 0.5 in.
Find: Porosity corrected for standoff.
Answer: Draw a vertical line from the uncorrected neutron logporosity of 34 p.u. Enter the 12-in. borehole chart at 0.5-in. standoff and move horizontally right to intersectthe vertical porosity line. From the point of intersectionmove parallel to the closest trend line to intersect thestandard conditions line (standoff = 0 in.). The standoff-corrected porosity is 32 p.u. The correction is –2 p.u.
Compensated Neutron ToolStandoff Correction—Open Hole
61
Neu
Neutron—Wireline
Compensated Neutron ToolStandoff Correction—Open Hole Neu-3
(customary, former Por-14d)
0 10 20 30 40 50
0 10 20 30 40 50
10
9
8
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
4
3
2
1
0
3
2
1
0
2
1
0
1
0
Actual borehole size
6 in.
8 in.
10 in.
12 in.
18 in.
24 in.
Standoff (in.)
• Standard conditions
Neutron log porosity index (apparent limestone porosity in p.u.)
•
•
•
•
•
•
© Schlumberger
Neutron—Wireline
62
Neu
Compensated Neutron ToolStandoff Correction—Open Hole Neu-4
(metric, former Por-14dm)
0 10 20 30 40 50
0 10 20 30 40 50
250
225
200
175
150
125
100
75
50
25
0
175
150
125
100
75
50
25
0
100
75
50
25
0
75
50
25
0
50
25
0
25
0
Actual borehole size
150 mm
200 mm
250 mm
300 mm
450 mm
600 mm
Standoff (mm)
• Standard conditions
Neutron log porosity index (apparent limestone porosity)
•
•
•
•
•
•
PurposeThis chart is the metric version of Chart Neu-3 for determining theporosity change caused by standoff.
© Schlumberger
63
Neu
Neutron—Wireline
Compensated Neutron ToolConversion of NPHI to TNPH—Open Hole Neu-5
(former Por-14e)
PurposeThis chart is used to determine the porosity change caused by theborehole size to the neutron porosity NPHI and convert the porosityto thermal neutron porosity (TNPH). This chart corrects NPHI onlyfor the borehole sizes that differ from the standard condition of 8 in.Refer to Chart Neu-1 to complete the environmental corrections forthe TPNH value obtained.
DescriptionEnter the scale at the top of the chart with the NPHI porosity.
ExampleGiven: NPHI porosity = 12.5% and borehole size = 16 in.
Find: Porosity correction for nonstandard borehole size.
Answer: Enter the chart with the uncorrected porosity value of 12.5 at the scale at the top. Move down vertically to intersect the standard conditions line indicated by the bullet to the right. Enter the chart on the y-axis withthe actual borehole size at the zone of interest and movehorizontally right across the chart.
At the point of intersection of the vertical line and thestandard conditions line, move parallel to the closesttrend line to intersect the actual borehole size line.
At that intersection point move vertically down to thebottom scale to determine the TNPH porosity correctedonly for borehole size. This value is also used to deter-mine the change in porosity as a result of tool standoff.
TNPH = 12.5 + 5 = 17.5 p.u.
TNPH porosity index (apparent limestone porosity in p.u.)
2420161284
Borehole size(in.)
–5 0 10 20 30 40 50
0 10 20 30 40 50
NPHI porosity index (apparent limestone porosity in p.u.)
•
• Standard conditions
© Schlumberger
64
Neu
Neutron—Wireline
Compensated Neutron ToolFormation Σ Correction for Environmentally Corrected TNPH—Open Hole
PurposeThis chart is used to further correct the environmentally correctedTNPH porosity from Chart Neu-1 for the effect of the total forma-tion capture cross section, or sigma (Σ), of the formation of inter-est. This correction is applied after all environmental correctionsdetermined with Chart Neu-1 have been applied.
DescriptionEnter the chart with Σ for the appropriate formation along the y-axisand the corrected TNPH porosity along the x-axis. Where the linesdrawn from these points intersect, move parallel to the closest trendline to intersect the appropriate fresh- or saltwater line to read thecorrected porosity.
The chart at the bottom of the page is used to correct the Σ-corrected porosity for salt displacement if the formation Σ is due tosalinity. However, this correction is not made if the borehole salinitycorrection from Chart Neu-1 has been applied.
ExampleGiven: Corrected TNPH from Chart Neu-1 = 38 p.u., Σ of the
sandstone formation = 33 c.u., and formation salinity =150,000 ppm (indicating a freshwater formation).
Find: TNPH porosity corrected with Chart Neu-1 and for Σ ofthe formation.
Answer: Enter the appropriate chart with the Σ value on the y-axisand the corrected TNPH value on the x-axis. At the inter-section of the sigma and porosity lines, parallel the clos-est trend line to intersect the freshwater line. (If thewater in the formation is salty, the 250,000-ppm lineshould be used.)
Move straight down from the intersection point to theformation salinity chart at the bottom.
From the point where the straight line intersects the topof the salinity correction chart, parallel the closest trendline to intersect the formation salinity line.
Draw a vertical line to the bottom scale to read the cor-rected formation sigma TNPH porosity, which is 35 p.u.
65
Neu
0 10 20 30 40 50
0 10 20 30 40 50
0
100
250
70
60
50
40
30
20
10
0
70
60
50
40
30
20
10
0
Neutron log porosity index
Sandstone formationFormation Σ (c.u.)
Fresh water
250,000-ppm water
Limestone formationFormation Σ (c.u.)
Fresh water
250,000-ppm water
Dolomite formationFormation Σ (c.u.)
Formation salinity(1,000 × ppm)
Fresh water
250,000-ppm water
70
60
50
40
30
20
10
0
Neutron—Wireline
Compensated Neutron ToolFormation Σ Correction for Environmentally Corrected TNPH—Open Hole Neu-6
(former Por-16)
© Schlumberger
66
Neu
Neutron—Wireline
Compensated Neutron ToolMineral Σ Correction for Environmentally Corrected TNPH—Open Hole
PurposeThis chart is used to further correct the environmentally correctedTNPH porosity from Chart Neu-1 for the effect of the mineral sigma(Σ). This correction is applied after all environmental correctionsdetermined with Chart Neu-1 have been applied.
DescriptionEnter the chart for the formation type with the mineral Σ value alongthe y-axis and the Chart Neu-1 corrected TNPH porosity along the x-axis. Where lines drawn from these points intersect, move parallel tothe closest trend line to intersect the freshwater line to read thecorrected porosity on the scale at the bottom. The choice of chartdepends on the type of mineral in the formation.
ExampleGiven: Corrected TNPH from Chart Neu-1 = 38 p.u., sandstone
formation Σ = 35 c.u., and formation salinity = 150,000 ppm (indicating a freshwater formation).
Find: TNPH porosity corrected with Chart Neu-1 and for themineral Σ.
Answer: At the intersection of the Σ and porosity value linesmove parallel to the closest trend line to intersect thefreshwater line. Move straight down to intersect the bot-tom prosity scale to read the TNPH porosity correctedfor mineral Σ, which is 33 p.u.
67
Neu
Neutron—Wireline
Compensated Neutron ToolMineral Σ Correction for Environmentally Corrected TNPH—Open Hole
0 10 20 30 40 50
0 10 20 30 40 50
Neutron log porosity index
Sandstone formationMineral Σ (c.u.)
Fresh water
Fresh water
Fresh water
70
60
50
40
30
20
10
0
Limestone formationMineral Σ (c.u.)
70
60
50
40
30
20
10
0
Dolomite formationMineral Σ (c.u.)
70
60
50
40
30
20
10
0
Neu-7(former Por-17)
© Schlumberger
68
Neu
GeneralNeutron—Wireline
Compensated Neutron ToolFluid Σ Correction for Environmentally Corrected TNPH—Open Hole
PurposeThis chart is used to correct the environmentally corrected TNPHporosity from Chart Neu-1 for the effect of the fluid sigma (Σ) inthe formation. This correction is applied after all environmental corrections determined with Chart Neu-1 have been applied.
DescriptionEnter the appropriate formation chart with the formation fluid Σvalue on the y-axis and the Chart Neu-1 corrected TNPH porosity onthe x-axis. Where the lines drawn from these points intersect, moveparallel to the closest trend line to intersect the appropriate fresh-or saltwater line. If the borehole salinity correction from Chart Neu-1has not been applied, from this point extend a line down to intersectthe formation salinity chart at the bottom. Move parallel to theclosest trend line to intersect the formation salinity line. Movestraight down to read the corrected porosity on the scale below the chart.
ExampleGiven: Corrected TNPH from Chart Neu-1 = 30 p.u. (without
borehole salinity correction), fluid Σ = 80 c.u., fluidsalinity = 150,000 ppm, and sandstone formation.
Find: TNPH corrected with Chart Neu-1 and for fluid Σ.
Answer: At the intersection of the fluid Σ and Chart Neu-1 corrected TNPH porosity (30-p.u.) line, move parallel to the closest trend line to intersect the freshwater line.
From that point go straight down to the formation salinitycorrection chart at the bottom.
Move parallel to the closest trend line to intersect theformation salinity line (150,000 ppm), and then draw avertical line to the bottom scale to read the correctedTNPH value (26 p.u.).
69
Neu
0 10 20 30 40 50
0 10 20 30 40 50
Neutron log porosity index
Sandstone formationFluid Σ (c.u.)
Limestone formationFluid Σ (c.u.)
Dolomite formationFluid Σ (c.u.)
Formation salinity(1,000 × ppm)
160
140
120
100
80
60
40
20160
140
120
100
80
60
40
20160
140
120
100
80
60
40
200
250
Fresh water
250,000-ppm water
Fresh water
250,000-ppm water
Fresh water
250,000-ppm water
Neutron—Wireline
Compensated Neutron ToolFluid Σ Correction for Environmentally Corrected TNPH—Open Hole Neu-8
(former Por-18)
© Schlumberger
70
Neu
Neutron—Wireline
Compensated Neutron ToolEnvironmental Correction—Cased Hole
PurposeThis chart is used to obtain the correct porosity from the neutronporosity index logged with the compensated neutron tool in casing,where the effects of the borehole size, casing thickness, and cementsheath thickness influence the true value of formation porosity.
DescriptionEnter the scale at the top of the chart with a whole-number (notfractional) porosity value. Draw a straight line vertically through the three charts representing borehole size, casing thickness, andcement thickness. Draw a horizontal line on each chart from theappropriate value on the y-axis. At the intersection point of the verti-cal line and the horizontal line on each chart proceed to the bluedashed horizontal line by following the slope of the blue solid lineson each chart. At that point read the change in porosity index. Thecumulative change in porosity is added to the logged porosity to obtainthe corrected value. As can be seen, the major influences to the casing-derived porosity are the borehole size and the cement thickness. Thesame procedure applies to the metric chart.
The blue dashed lines represent the standard conditions fromwhich the charts were developed: 83⁄4-in. open hole, 51⁄2-in. 17-lbmcasing, and 1.62-in. annular cement thickness.
The neutron porosity equivalence nomographs at the bottom areused to convert from the log standard of limestone porosity to poros-ity for other matrix materials.
The porosity value corrected with Chart Neu-9 is entered intoChart Neu-1 to provide environmental corrections necessary fordetermining the correct cased hole porosity value.
ExampleGiven: Log porosity index = 27%, borehole diameter = 11 in.,
casing thickness = 0.304 in., and cement thickness =1.62 in.
Cement thickness is defined as the annular spacebetween the outside wall of the casing and the boreholewall. The value is determined by subtracting the casingoutside diameter from the borehole diameter and divid-ing by 2.
Find: Porosity corrected for borehole size, casing thickness,and cement thickness.
Answer: Draw a vertical line (shown in red) though the threecharts at 27 p.u.
Borehole-diameter correction chart: From the intersec-tion of the vertical line and the 11-in. borehole-diameterline (shown in red dashes) move upward along thecurved blue line as shown on the chart.
The porosity is reduced to 26% by –1 p.u.
Casing thickness chart: The porosity index is changed by 0.3 p.u.
Cement thickness chart: The porosity index is changedby 0.5 p.u.
The resulting corrected porosity for borehole, casing,and cement is 27 – 1 + 0.3 + 0.5 = 26.8 p.u.
71
Neu
Neutron—Wireline
Compensated Neutron ToolEnvironmental Correction—Cased Hole
0 10 20 30 40 50
468
101214160.2
0.3
0.4
0.5
0
1
2
3
+0.3
+0.5Borehole, casing, and cement correction = –1.0 + 0.3 + 0.5
–1.0
1.62 in.
0.304 in.
83⁄4 in.
Neutron log porosity index (p.u.)
Diameter of boreholebefore running casing
(in.)
Cement thickness(in.)
Casing thickness (in.)9.5
11.613.515.1
14172023
20
26
32
29
40
47
41⁄2 51⁄2 7 95⁄8OD (in.)
Casingweight(lbm/ft)
Customary
•
•
•
0 10 20 30 40 50
0 10 20 30 40 50
0 10 20 30 40 50
0 10 20 30 40 50
0 10 20 30
100
200
300
400579
1113
0
25
50
75
41 mm
7.7 mm
222 mm
Neutron log porosity index (p.u.)
Diameter of boreholebefore running casing
(mm)
Cement thickness(mm)
Casing thickness (mm)14172023
21.025.530.034.5
30
39
48
43
60
70
114 140 178 245OD (mm)
Casingweight(kg/m)
Metric
• Standard conditions
Calcite (limestone)
Quartz sandstone
Dolomite
Neutron porosity equivalence
•
•
•
Neu-9(former Por-14a)
© Schlumberger
72
Neu
Neutron—Wireline
APS* Accelerator Porosity SondeEnvironmental Correction—Open Hole
PurposeThe Neu-10 charts pair is used to correct the APS Accelerator PorositySonde apparent limestone porosity for mud weight and actual bore-hole size. The charts are for the near-to-array and near-to-far poros-ity measurements. The design of the APS sonde resulted in asignificant reduction in environmental correction. The answer deter-mined with this chart is used in conjunction with the correctionfrom Chart Neu-11.
DescriptionEnter the appropriate chart pair (mud weight and actual boreholesize) for the APS near-to-array apparent limestone porosity (APLU)or APS near-to-far apparent limestone porosity (FPLU) with theuncorrected porosity from the APS log by drawing a straight verticalline (shown in red) through both of the charts. At the intersectionwith the mud weight value, move parallel to the closest trend line tointersect the standard conditions line. This point represents a changein porosity resulting from the correction for mud weight. Follow thesame procedure for the borehole size chart to determine that correc-tion change. Because the borehole size correction has a dependencyon mud weight, even with natural muds, there are two sets of curveson the borehole size chart—solid for light muds (8.345 lbm/gal) anddashed for heavy muds (16 lbm/gal). Intermediate mud weights areinterpolated. The two differences are summed for the total correc-tion to the APS log value.
This answer is used in Chart Neu-11 to complete the environ-mental corrections for corrected APLU or FPLU porosity.
ExampleGiven: APS neutron APLU uncorrected porosity = 34 p.u.,
mud weight = 10 lbm/gal, and borehole size = 12 in.
Find: Corrected APLU porosity.
Answer: Draw a vertical line on the APLU mud weight chart from34 p.u. on the scale above. At the intersection with the10-lbm/gal mud weight line, move parallel to the trendline to intersect the standard conditions line. This pointrepresents a change in porosity of –0.75 p.u.
On the actual borehole size chart, move parallel to theclosest trend line from the intersection of the 34-p.u.line and the actual borehole size (12 in.) to intersect the 8-in. standard conditions line. This point represents a change in porosity of –1.0 p.u.
The total correction is –0.75 + –1.0 = –1.75 p.u., which results in a corrected APLU porosity of34 – 1.75 = 32.25 p.u.
73
Neu
Neutron—Wireline
APS near-to-far apparent limestone porosity uncorrected, FPLU (p.u.)
0 10 20 30 40 50
Mud weight (lbm/gal)
Actualborehole size
(in.)
18161412108
1614121086
2.01.81.61.41.21.0
400350300250200
(g/cm3)
(mm)
•
•
APS near-to-array apparent limestone porosity uncorrected, APLU (p.u.)
0 10 20 30 40 50
Mud weight(lbm/gal)
Actualborehole size
(in.)
18161412108
1614121086
2.01.81.61.41.21.0
400350300250200
(g/cm3)
(mm)
•
•
• Standard conditions
APS* Accelerator Porosity SondeEnvironmental Correction—Open Hole Neu-10
(former Por-23a)
*Mark of Schlumberger© Schlumberger
74
Neu
Neutron—Wireline
PurposeThis chart is used to complete the environmental correction forAPLU and FPLU porosities from the APS log.
DescriptionEnter the left-hand chart on the x-axis with the temperature of theformation of interest. Move vertically to intersect the appropriateformation pressure line. From that point, move horizontally right tointersect the left edge of the formation salinity chart. Move parallelto the trend lines to intersect the formation salinity value. From thatpoint move horizontally to intersect the left edge of the formationporosity chart. Move parallel to the trend lines to intersect theuncorrected APLU or FPLU porosity. At that intersection, move horizontally right to read the apparent porosity correction.
ExampleGiven: APLU or FPLU porosity = 34 p.u., formation tempera-
ture = 150°F, formation pressure = 5,000 psi, and for-mation salinity = 150,000 ppm.
Find: Environmentally corrected APLU or FPLU porosity.
Answer: Enter the formation temperature chart at 150°F to inter-sect the 5,000-psi curve. From that point move horizon-tally right to intersect the left edge of the formationsalinity chart. Move parallel to the trend lines to inter-sect the formation temperature of 150°F. At this point,again move horizontally to the left edge of the nextchart. Move parallel to the trend lines to intersect the34-p.u. porosity line. At that point on the y-axis, thechange in porosity is +1.6 p.u.
The total correction for a corrected APLU or FPLU from Charts Neu-10 and Neu-11 is 34 + (–0.75 + –1) + 1.6 = 33.85 p.u.
50 100 150 200 250 300 350 10 38 66 93 121 149 177
50 150 250
Formation salinity(ppt or g/kg)
Formation porosity (p.u.)
50 30 10 0
Formation temperature
(°F) (°C)
1211109876543210
–1
Apparent porosity
correction(p.u.)
(psi) (MPa) 0 0 2,500 5,000 34 7,500 10,000 69 12,500 15,000 103 17,500 20,000 138
Pressure
APS* Accelerator Porosity Sonde Without Environmental Corrections Environmental Correction—Open Hole Neu-11
(former Por-23b)
*Mark of Schlumberger© Schlumberger
75
Neu
Neutron—LWD
PurposeThis chart is used to determine one of several environmental corrections for neutron porosity values recorded with the CDNCompensated Density Neutron and adnVISION Azimuthal DensityNeutron tools. The value of hydrogen index (Hm) is used in thefollowing porosity correction charts.
DescriptionTo determine the Hm of the drilling mud, the mud weight, tempera-ture, and hydrostatic mud pressure at the zone of interest must be known.
ExampleGiven: Barite mud weight = 14 lbm/gal, mud temperature = 150°F,
and hydrostatic mud pressure = 5,000 psi.
Find: Hydrogen index of the drilling mud.
Answer: Enter the bottom chart for mud weight at 14 lbm/gal onthe y-axis. Move horizontally to intersect the barite line.
Move vertically to the bottom of the mud temperaturechart and move upward parallel to the closest trend lineto intersect the formation temperature. From the inter-section point move vertically to the bottom of the mudpressure chart.
Move parallel to the closest trend line to intersect theformation pressure. Draw a line vertically to intersectthe mud hydrogen index scale and read the result.
Mud hydrogen index = 0.78.
CDN* Compensated Density Neutron and adnVISION* Azimuthal Density Neutron ToolsMud Hydrogen Index Determination
continued on next page
76
Neu
Neutron—LWD
CDN* Compensated Density Neutron and adnVISION*Azimuthal Density Neutron ToolsMud Hydrogen Index Determination
Neu-30(former Por-19)
0.70 0.75 0.80 0.85 0.90 0.95 1
0.70 0.75 0.80 0.85 0.90 0.95 1
25
20
10
0
Mudpressure
(1,000 × psi)
300
200
100
50
Mudtemperature
(°F)
16
14
12
10
8
Mudweight
(lbm/gal)
Mud hydrogen index, Hm
Barite
Bentonite
*Mark of Schlumberger© Schlumberger
77
Neu
Neutron—LWD
PurposeThis is one of a series of charts used to correct adnVISION475 4.75-in. Azimuthal Density Neutron tool porosity for several environ-mental effects by using the mud hydrogen index (Hm) determinedfrom Chart Neu-30 in conjunction with the parameters on the chart.
DescriptionThis chart incorporates the parameters of borehole size, mud tem-perature, mud hydrogen index (from Chart Neu-30), mud salinity,and formation salinity for the correction of adnVISION475 porosity.
The following charts are used with the same interpretation procedure as Chart Neu-31. The charts differ for tool size and borehole size.
ExampleGiven: adnVISION475 uncorrected porosity = 34 p.u., borehole
size = 10 in., mud temperature = 150°F, hydrogen index = 0.78, borehole salinity = 100,000 ppm, and forma-tion salinity = 100,000 ppm.
Find: Corrected adnVISION475 porosity.
Answer: From the adnVISION475 porosity of 34 p.u. on the topscale, enter the borehole size chart to intersect the bore-hole size of 10 in. From the point of intersection moveparallel to the closest trend line to intersect the stan-dard conditions line.
From this intersection point move straight down to enter the mud temperature chart and intersect the mudtemperature of 150°F. From the point of intersectionmove parallel to the closest trend line to intersect thestandard conditions line.
Continue this pattern through the charts to read the corrected porosity from the scale at the bottom of thecharts.
The corrected adnVISION475 porosity is 17 p.u.
adnVISION475* Azimuthal Density Neutron—4.75-in. Tool and 6-in. BoreholeEnvironmental Correction—Open Hole
continued on next page
78
Neu
Neutron—LWD
adnVISION475* Azimuthal Density Neutron—4.75-in. Tool and 6-in. BoreholeEnvironmental Correction—Open Hole Neu-31
Boreholesize(in.)
0 10 20 30 40 50
Mudhydrogenindex, Hm
0 10 20 30 40 50
Mudsalinity
(1,000 × ppm)
Formationsalinity
(1,000 × ppm)
• Standard conditions
Mudtemperature
(°F)
•
•
•
•
•
6
8
10
100
0.7
0.8
0.9
1.0
200
300
0
100
200
adnVISION475 neutron porosity index (apparent limestone porosity) in 6-in. borehole
0
100
200
*Mark of Schlumberger© Schlumberger
79
Neu
Neutron—LWD
adnVISION475* BIP Neutron—4.75-in. Tool and 6-in. BoreholeEnvironmental Correction—Open Hole Neu-32
0 10 20 30 40 50
Mudhydrogenindex, Hm
0 10 20 30 40 50
Mudsalinity
(1,000 × ppm)
Formationsalinity
(1,000 × ppm)
Mudtemperature
(°F)
adnVISION475 neutron porosity index (apparent limestone porosity) in 6-in. borehole
100
0.7
0.8
0.9
1.0
200
300
100
200
0
0
100
200
PurposeThis chart is used similarly to Chart Neu-31 to correctadnVISION475 borehole-invariant porosity (BIP) measurements.
DescriptionEnter the top scale with the BIP neutron porosity (BNPH) to incor-porate corrections for mud temperature, mud hydrogen index, andmud and formation salinity.
*Mark of Schlumberger© Schlumberger
80
Neu
Neutron—LWD
adnVISION475* Azimuthal Density Neutron—4.75-in. Tool and 8-in. BoreholeEnvironmental Correction—Open Hole
Neu-33
Boreholesize(in.)
0 10 20 30 40 50
Mudhydrogenindex, Hm
0 10 20 30 40 50
Mudsalinity
(1,000 × ppm)
Formationsalinity
(1,000 × ppm)
• Standard conditions
Mudtemperature
(°F)
•
•
•
•
•
6
8
10
100
0.7
0.8
0.9
1.0
200
300
0
100
200
adnVISION475 neutron porosity index (apparent limestone porosity) in 8-in. borehole
0
100
200
PurposeThis chart is used similarly to Chart Neu-31 to correctadnVISION475 porosity.
*Mark of Schlumberger© Schlumberger
81
Neu
Neutron—LWD
adnVISION475* BIP Neutron—4.75-in. Tool and 8-in. BoreholeEnvironmental Correction—Open Hole Neu-34
0 10 20 30 40 50
Mudhydrogenindex, Hm
0 10 20 30 40 50
Mudsalinity
(1,000 × ppm)
Formationsalinity
(1,000 × ppm)
Mudtemperature
(°F)
adnVISION675 neutron porosity index (apparent limestone porosity) in 8-in. borehole
100
0.7
0.8
0.9
1.0
200
300
100
200
0
0
100
200
PurposeThis chart is used similarly to Chart Neu-32 to correctadnVISION475 borehole-invariant porosity (BIP) measurements.
*Mark of Schlumberger© Schlumberger
82
Neu
Neutron—LWD
250
200
100
0
Formationsalinity
(1,000 × ppm)
•
250
200
100
0
Mudsalinity
(1,000 × ppm)
•
300
200
100
50
Mudtemperature
(°F)
•
0.7
0.8
0.9
1.0
Mudhydrogenindex, Hm
•
• Standard conditions
adnVISION675 neutron porosity index (apparent limestone porosity in p.u.)
0 10 20 30 40 50
0 10 20 30 40 50
16
14
12
10
8
Boreholesize(in.)
•
adnVISION675* Azimuthal Density Neutron—6.75-in. Tool and 8-in. BoreholeEnvironmental Correction—Open Hole Neu-35
(former Por-26a)
PurposeThis chart is used similarly to Chart Neu-31 to correct adnVISION675porosity.
*Mark of Schlumberger© Schlumberger
adnVISION675* BIP Neutron—6.75-in. Tool and 8-in. BoreholeEnvironmental Correction—Open Hole
0 10 20 30 40 50
Mudhydrogenindex, Hm
0 10 20 30 40 50
Mudsalinity
(1,000 × ppm)
Formationsalinity
(1,000 × ppm)
Mudtemperature
(°F)
adnVISION675 neutron porosity index (apparent limestone porosity) in 8-in. borehole
100
0.7
0.8
0.9
1.0
200
300
100
200
0
0
100
200
PurposeThis chart is used similarly to Chart Neu-32 to correctadnVISION675 borehole-invariant porosity (BIP) measurements.
83
Neu
Neutron—LWD
Neu-36
*Mark of Schlumberger© Schlumberger
84
Neu
Neutron—LWD
adnVISION675* Azimuthal Density Neutron—6.75-in. Tool and 10-in. BoreholeEnvironmental Correction—Open Hole Neu-37
(former Por-26b)
250
200
100
0
Formationsalinity
(1,000 × ppm)
•
250
200
100
0
Mudsalinity
(1,000 × ppm)
•
300
200
100
50
Mudtemperature
(°F)
•
0.7
0.8
0.9
1.0
Mudhydrogenindex, Hm
•
adnVISION675 neutron porosity index (apparent limestone porosity in p.u.)
0 10 20 30 40 50
0 10 20 30 40 50
16
14
12
10
8
Boreholesize(in.)
•
• Standard conditions
PurposeThis chart is used similarly to Chart Neu-31 to correct adnVISION675 porosity.
*Mark of Schlumberger© Schlumberger
85
Neu
Neutron—LWD
adnVISION675* BIP Neutron—6.75-in. Tool and 10-in. BoreholeEnvironmental Correction—Open Hole
0 10 20 30 40 50
Mudhydrogenindex, Hm
0 10 20 30 40 50
Mudsalinity
(1,000 × ppm)
Formationsalinity
(1,000 × ppm)
Mudtemperature
(°F)
adnVISION675 neutron porosity index (apparent limestone porosity) in 10-in. borehole
100
0.7
0.8
0.9
1.0
200
300
100
200
0
0
100
200
PurposeThis chart is used similarly to Chart Neu-32 to correctadnVISION675 borehole-invariant porosity (BIP) measurements.
Neu-38
*Mark of Schlumberger© Schlumberger
Neu
Neutron—LWD
86
adnVISION825* Azimuthal Density Neutron—8.25-in. Tool and 12.25-in. BoreholeEnvironmental Correction—Open Hole
Neu-39
Standoff(in.)
0 10 20 30 40 50
Mudtemperature
(°F)
Mudhydrogenindex, Hm
Pressure(1,000 × psi)
Boreholesize(°F)
1.5
0.5
0
1.0
12
10
300
200
100
14
16
1
0.7
0.8
0.9
adnVISION825 neutron porosity index (apparent limestone porosity) in 12.25-in. borehole
Standoff = 0.25 in.
0
10
20
0 10 20 30 40 50
Mudsalinity
(1,000 × ppm)
Formationsalinity
(1,000 × ppm)
0
100
200
0
100
200
• Standard conditions
•
•
•
•
•
•
•
PurposeThis chart is used similarly to Chart Neu-31 to correct adnVISION825 porosity.
*Mark of Schlumberger© Schlumberger
Neutron—LWD
87
Neu
CDN* Compensated Density Neutron and adnVISION825s* Azimuthal Density Neutron—8-in. Tool and 12-in. BoreholeEnvironmental Correction—Open Hole
Neu-40(former Por-24c)
18
16
14
12
Boreholesize(in.)
Neutron porosity index (apparent limestone porosity) in 12-in. borehole
0 10 20 30 40 50
0 10 20 30 40 50
Mudsalinity
(1,000 × ppm)
Formationsalinity
(1,000 × ppm)
• Standard conditions
•
•
•
•
•
250
200
100
0
250
200
100
0
0.7
0.8
0.9
1.0
Mudhydrogenindex, Hm
350300
200
10050
Mudtemperature
(°F)
PurposeThis chart is used similarly to Chart Neu-31 to correct CDN Compensated Density Neutron tool and adnVISION825sAzimuthal Density Neutron porosity.
*Mark of Schlumberger© Schlumberger
88
Neu
Neutron—LWD
CDN* Compensated Density Neutron and adnVISION825s* Azimuthal Density Neutron—8-in. Tool and 14-in. BoreholeEnvironmental Correction—Open Hole
Neu-41(former Por-24d)
350
300
200
100
50
Mudtemperature
(°F)
18
16
14
12
Boreholesize(in.)
Neutron porosity index (apparent limestone porosity) in 14-in. borehole
0 10 20 30 40 50
0 10 20 30 40 50
Mudsalinity
(1,000 × ppm)
Formationsalinity
(1,000 × ppm)
• Standard conditions
•
•
•
•
•
250
200
100
0
250
200
100
0
A
B
C
G
H
I
J
K
0.7
0.8
0.9
1.0
Mudhydrogenindex, Hm
D
E
F
*Mark of Schlumberger© Schlumberger
89
Neu
Neutron—LWD
CDN* Compensated Density Neutron and adnVISION825s* Azimuthal Density Neutron—8-in. Tool and 16-in. BoreholeEnvironmental Correction—Open Hole
18
16
14
12
Boreholesize(in.)
0.7
0.8
0.9
1.0
Mudhydrogenindex, Hm
Neutron porosity index (apparent limestone porosity) in 16-in. borehole
0 10 20 30 40 50
0 10 20 30 40 50
Mudsalinity
(1,000 × ppm)
Formationsalinity
(1,000 × ppm)
• Standard conditions
•
•
•
•
•
250
200
100
0
250
200
100
0
350
300
200
100
50
Mudtemperature
(°F)
Neu-42(former Por-24e)
*Mark of Schlumberger© Schlumberger
90
NMR
Nuclear Magnetic Resonance–—Wireline
CMR* ToolHydrocarbon Effect on NMR/Density Porosity Ratio CMR-1
PurposeThis chart is used to determine the saturation of the flushed zone(Sxo) and hydrocarbon density (ρh) by using density (ρ) and CMRCombinable Magnetic Resonance data.
DescriptionThe top chart has three components: ratio of total CMR porosity to density porosity (φtCMR/φD) on the y-axis, (1 – Sxo) values on the x-axis, and ρh defined by the radiating lines from the value of unityon the y-axis. Enter the chart with the values for (1 – Sxo) and theφtCMR/φD ratio. The intersection point indicates the hydrocarbon
density value. The bottom charts are used to determine the Sxo valuein sandstone (left) and limestone (right).
ExampleGiven: CMR porosity = 25 p.u., φD = 30 p.u., and Sxo = 80%.
Find: Hydrocarbon density of the fluid in the formation.
Answer: φtCMR/φD ratio = 25/30 = 0.83.
1 – Sxo = 1 – 0.8 = 0.20 or 20%.
For these values, ρh = 0.40.
1.0
1.0
0.80.7
0.6
0.5
0.4
0.3
0.2
0.1
0.8
0.4
0.4
0.2
0.20
0
0.6
0.6
1 – Sxo
1.4
1.6
1.8
2.0
0
10 p.u.
0
10 p.u.
20 p.u. 20 p.u.
Gas Gas30 p.u. 30 p.u.
40 p.u. 40 p.u.
0%20%
40%60%
80%
0%
20%40%
60%80%
Sxo = 100% Sxo = 100%
WaterWater
Porosity = 50 p.u. Porosity = 50 p.u.
2.2
2.4
2.6
0 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0 0.05 0.10 0.15 0.20 0.25
φtCMR
0.30 0.35 0.40 0.45 0.50
1.4
1.6
1.8
2.0
2.2
2.4
2.6
ρb (g/cm3)
ρb (g/cm3)
ρma = 2.65, ρf = 1, If = 1, ρgas = 0.25, PT = 4, T1 gas = 4, IH = 0.5
Fresh Mud and Dry Gas at 700 psi Fresh Mud and Dry Gas at 700 psi
ρma = 2.71, ρf = 1, If = 1, ρgas = 0.25, PT = 4, T1 gas = 4, Igas = 0.5
φtCMRφD
φtCMR
ρh = 0.8
*Mark of Schlumberger© Schlumberger
Resistivity Laterolog—Wireline
91
ARI* Azimuthal Resistivity ImagerEnvironmental Correction—Open Hole RLl-1
(former Rcor-14)
PurposeThis chart is used to environmentally correct the ARI AzimuthalResistivity Imager high-resolution resistivity (LLhr) curve for theeffect of borehole size.
DescriptionFor a known value of resistivity of the borehole mud (Rm) at the zoneof interest, a correction for the recorded log azimuthal resistivity (Ra)is determined by using this chart. The resistivity measured by theARI tool is equal to or higher than the corrected resistivity (Rt) forborehole sizes of 8 to 12 in. However, the measured ARI resistivity is lower than Rt in 6-in. boreholes and for values of Ra/ Rm between 6 and 600.
ExampleGiven: ARI LLhr resistivity (Ra) = 20 ohm-m, mud resistivity
(Rm) = 0.02 ohm-m, and borehole size at the zone ofinterest = 10 in.
Find: True resistivity (Rt).
Answer: Enter the chart at the x-axis with the ratio Ra/Rm =20/0.02 = 1,000.
Move vertically upward to intersect the 10-in. line. Movehorizontally left to read the Rt/Ra value on the y-axis of 0.86.
Multiply the ratio by Ra to obtain the corrected LLhr
resistivity: Rt = 0.86 × 20 = 17.2 ohm-m.
1 10 100 1,000 10,000
1.5
1.0
0.5
Ra/Rm
Rt/Ra
35⁄8-in. Tool Centered, Active Mode, Thick Beds
68
1012
Hole diameter (in.)
RLl*Mark of Schlumberger© Schlumberger
Resistivity Laterolog—Wireline
RLl
92
PurposeThis chart is used to correct the HALS laterolog deep resistivity(HLLD) for borehole and drilling mud effects.
DescriptionEnter the chart on the x-axis with the value of HLLD divided by the mud resistivity (Rm) at formation temperature. Move upward to intersect the curve representing the borehole diameter (dh), andthen move horizontally left to read the value of the ratio Rt/HLLD onthe y-axis. Multiply this value by the HLLD value to obtain Rt. Charts
RLl-3 through RLl-14 are similar to Chart RLl-2 for different resistivitymeasurements and values of tool standoff.
ExampleGiven: HLLD = 100 ohm-m, Rm = 0.02 ohm-m at formation
temperature, and borehole size = 10 in.
Find: Rt.
Answer: Ratio of HLLD/Rm = 100/0.02 = 5,000.
Rt = 0.80 × 100 = 80 ohm-m.
High-Resolution Azimuthal Laterolog Sonde (HALS)HLLD Borehole Correction—Open Hole RLl-2
10–1 100 101 102 103 104 1050.6
0.7
0.8
0.9
1.0
1.1
1.2
HLLD/Rm
R t /HLLD
HLLD Tool Centered (Rm = 0.1 ohm-m)
100 101 102 103 104 1050.5
0.7
0.9
1.1
1.3
1.5
HLLD/Rm
R t /HLLD
Borehole Effect, HLLD Tool Centered (Rm = 0.1 ohm-m)
dh
5 in.6 in.8 in.10 in.12 in.14 in.16 in.
dh6 in.8 in.10 in.12 in.14 in.16 in.18 in.20 in.
© Schlumberger
93
RLl
Resistivity Laterolog—Wireline
High-Resolution Azimuthal Laterolog Sonde (HALS)HLLS Borehole Correction—Open Hole RLl-3
PurposeThis chart is used similarly to Chart RLl-2 to correct HALS laterologshallow resistivity (HLLS) for borehole and drilling mud effects.
Borehole Effect, HLLS Tool Centered (Rm = 0.1 ohm-m)
dh6 in.8 in.10 in.12 in.14 in.16 in.18 in.20 in.
10–1 100 101 102 103 104 105 0
0.5
1.0
1.5
2.0
2.5
3.0
HLLS/Rm
Rt /HLLS
HLLS Tool Centered (Rm = 0.1 ohm-m)
100 101 102 103 104 105 0
1.0
0.5
1.5
2.0
2.5
3.0
HLLS/Rm
Rt/HLLS
dh5 in.6 in.8 in.10 in.12 in.14 in.16 in.
© Schlumberger
Resistivity Laterolog—Wireline
94
RLl
PurposeThis chart is used to similarly to Chart RLl-2 to correct the HALShigh-resolution deep resistivity (HRLD) for borehole and drillingmud effects.
High-Resolution Azimuthal Laterolog Sonde (HALS)HRLD Borehole Correction—Open Hole RLl-4
HRLD Tool Centered (R m = 0.1 ohm-m)
dh5 in. 6 in.8 in.10 in. 12 in.14 in.16 in.
100 101 102 103 104 105
Borehole Effect, HRLD Tool Centered (Rm = 0.1 ohm-m)
10–1 100 101 102 103 104 1050.4
0.5
0.6
0.7
0.8
1.0
0.9
1.1
R t/HRLD
HRLD/Rm
0.4
0.6
0.8
1.0
1.2
1.4
HRLD/Rm
Rt/HRLD
dh6 in.8 in.10 in.12 in.14 in.16 in.18 in.20 in.
© Schlumberger
95
RLl
Resistivity Laterolog—Wireline
High-Resolution Azimuthal Laterolog Sonde (HALS)HRLS Borehole Correction—Open Hole RLl-5
PurposeThis chart is used to similarly to Chart RLl-2 to correct the HALShigh-resolution shallow resistivity (HRLS) for borehole and drillingmud effects.
HRLS Tool Centered (Rm = 0.1 ohm-m)
dh5 in. 6 in. 8 in.10 in.12 in. 14 in.16 in.
HRLS/Rm
Borehole Effect, HRLS Tool Centered (Rm = 0.1 ohm-m)
10–1 100 101 102 103 104 105 0
0.5
1.0
1.5
2.0
2.5
3.0
HRLS/Rm
R t /HRLS
100 101 102 103 104 105 0
1.0
0.5
1.5
2.0
2.5
3.0
Rt/HRLS
dh6 in.8 in. 10 in.12 in. 14 in.16 in. 18 in. 20 in.
© Schlumberger
Resistivity Laterolog—Wireline
96
RLl
PurposeThis chart is used to similarly to Chart RLl-2 to correct the HALS laterolog deep resistivity (HLLD) for borehole and drilling mud effectsat 0.5- and 1.5-in. standoffs.
High-Resolution Azimuthal Laterolog Sonde (HALS)HLLD Borehole Correction—Eccentered in Open Hole RLl-6
dh5 in.6 in.8 in. 10 in.12 in.14 in. 16 in.
HLLD Tool Eccentered at Standoff = 0.5 in. (Rm = 0.1 ohm-m)
HLLD Tool Eccentered at Standoff = 1.5 in. (Rm = 0.1 ohm-m)
10–1 100 101 102 103 104 1050.6
0.8
0.7
0.9
1.0
1.1
1.2
Rt/HLLD
10–1 100 101 102 103 104 1050.6
0.7
0.8
0.9
1.0
1.1
1.2
HLLD/Rm
HLLD/Rm
Rt/HLLD
dh8 in. 10 in.12 in.14 in. 16 in.
© Schlumberger
97
RLl
Resistivity Laterolog—Wireline
High-Resolution Azimuthal Laterolog Sonde (HALS)HLLS Borehole Correction—Eccentered in Open Hole RLl-7
PurposeThis chart is used to similarly to Chart RLl-2 to correct the HALS laterolog shallow resistivity (HLLS) for borehole and drilling mud effects at 0.5- and 1.5-in. standoffs.
0
0.5
1.0
1.5
2.0
2.5
3.0
Rt/HLLS
0
0.5
1.0
1.5
2.0
2.5
3.0
Rt/HLLS
10–1 100 101 102 103 104 105
10–1 100 101 102 103 104 105
HLLS/Rm
HLLS/Rm
dh5 in.6 in.8 in.10 in.12 in.14 in.16 in.
HLLS Tool Eccentered at Standoff = 0.5 in. (Rm = 0.1 ohm-m)
dh8 in.10 in.12 in.14 in.16 in.
HLLS Tool Eccentered at Standoff = 1.5 in. (Rm = 0.1 ohm-m)
© Schlumberger
Resistivity Laterolog—Wireline
98
RLl
PurposeThis chart is used to similarly to Chart RLl-2 to correct the HALShigh-resolution deep resistivity (HRLD) for borehole and drillingmud effects at 0.5- and 1.5-in. standoffs.
High-Resolution Azimuthal Laterolog Sonde (HALS)HRLD Borehole Correction—Eccentered in Open Hole RLl-8
dh5 in. 6 in. 8 in.10 in. 12 in.14 in.16 in.
HRLD Tool Eccentered at Standoff = 0.5 in. (Rm = 0.1 ohm-m)
10–1 100 101 102 103 104 105
0.4
0.6
0.5
0.7
0.9
0.8
1.0
1.1
HRLD/Rm
Rt/HRLD
10–1 100 101 102 103 104 1050.4
0.6
0.5
0.7
0.8
0.9
1.0
1.1
HRLD/Rm
Rt/HRLD
dh8 in. 10 in.12 in.14 in.16 in.
HRLD Tool Eccentered at Standoff = 1.5 in. (Rm = 0.1 ohm-m)
© Schlumberger
99
RLl
Resistivity Laterolog—Wireline
High-Resolution Azimuthal Laterolog Sonde (HALS)HRLS Borehole Correction—Eccentered in Open Hole RLl-9
0
0.5
1.0
1.5
2.0
2.5
3.0
Rt/HRLS
10–1 100 101 102 103 104 105
HRLS/Rm
0
1.0
0.5
1.5
2.0
2.5
3.0
Rt/HRLS
10–1 100 101 102 103 104 105
HRLS/Rm
HRLS Tool Eccentered Standoff = 0.5 in. (Rm = 0.1 ohm-m)
HRLS Tool Eccentered Standoff = 1.5 in. (Rm = 0.1 ohm-m)
dh5 in.6 in.8 in. 10 in.12 in.14 in. 16 in.
dh8 in. 10 in.12 in.14 in. 16 in.
PurposeThis chart is used to similarly to Chart RLl-2 to correct the HALShigh-resolution shallow resistivity (HRLS) for borehole and drillingmud effects at 0.5- and 1.5-in. standoffs.
© Schlumberger
Resistivity Laterolog—Wireline
100
RLl
PurposeThis chart is used to similarly to Chart RLl-2 to correct HRLA High-Resolution Laterolog Array resistivity for borehole and drilling mud
effects. RLA1 is the apparent resistivity from computed focusingmode 1.
HRLA* High-Resolution Laterolog ArrayBorehole Correction—Open Hole RLl-10
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
Rt/RLA1
Tool Centered
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
Rt/RLA1
Standoff = 1.5 in.
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
Rt/RLA1
Standoff = 0.5 in.
dh5 in.6 in.8 in.9 in.10 in.12 in.14 in.16 in.18 in.20 in.22 in.
RLA1/Rm
RLA1/Rm
RLA1/Rm
*Mark of Schlumberger© Schlumberger
101
RLl
GeneralResistivity Laterolog—Wireline
HRLA* High-Resolution Laterolog ArrayBorehole Correction—Open Hole RLl-11
dh5 in.6 in.8 in.9 in.10 in.12 in.14 in.16 in.18 in.20 in.22 in.
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
Rt/RLA2
Tool Centered
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
Rt/RLA2
Standoff = 1.5 in.
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
Rt/RLA2
Standoff = 0.5 in.
RLA2/Rm
RLA2/Rm
RLA2/Rm
PurposeThis chart is used to similarly to Chart RLl-2 to correct HRLA High-Resolution Laterolog Array resistivity for borehole and drilling mud
effects. RLA2 is the apparent resistivity from computed focusingmode 2.
*Mark of Schlumberger© Schlumberger
Resistivity Laterolog—Wireline
RLl
102
HRLA* High-Resolution Laterolog ArrayBorehole Correction—Open Hole RLl-12
dh 5 in.6 in.8 in.9 in.10 in.12 in.14 in.16 in.18 in.20 in.22 in.
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
Rt/RLA3
Tool Centered
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
Rt/RLA3
Standoff = 1.5 in.
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
Rt/RLA3
Standoff = 0.5 in.
RLA3/Rm
RLA3/Rm
RLA3/Rm
PurposeThis chart is used to similarly to Chart RLl-2 to correct HRLA High-Resolution Laterolog Array resistivity for borehole and drilling mud
effects. RLA3 is the apparent resistivity from computed focusingmode 3.
*Mark of Schlumberger© Schlumberger
103
RLl
Resistivity Laterolog—Wireline
HRLA* High-Resolution Laterolog ArrayBorehole Correction—Open Hole RLl-13
dh 5 in.6 in.8 in.9 in.10 in.12 in.14 in.16 in.18 in.20 in.22 in.
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
Rt/RLA4
Tool Centered
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
Rt/RLA4
Standoff = 1.5 in.
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
Rt/RLA4
Standoff = 0.5 in.
RLA4/Rm
RLA4/Rm
RLA4/Rm
PurposeThis chart is used to similarly to Chart RLl-2 to correct HRLA High-Resolution Laterolog Array resistivity for borehole and drilling mud
effects. RLA4 is the apparent resistivity from computed focusingmode 4.
*Mark of Schlumberger© Schlumberger
Resistivity Laterolog—Wireline
104
RLl
HRLA* High-Resolution Laterolog ArrayBorehole Correction—Open Hole RLl-14
dh 5 in.6 in.8 in.9 in.10 in.12 in.14 in.16 in.18 in.20 in.22 in.
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
Rt/RLA5
Tool Centered
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
Rt/RLA5
Standoff = 1.5 in.
10–1 100 101 102 103 104 105 106
2.0
2.5
3.0
1.5
1.0
0.5
0
Rt/RLA5
Standoff = 0.5 in.
RLA5/Rm
RLA5/Rm
RLA5/Rm
PurposeThis chart is used to similarly to Chart RLl-2 to correct HRLA High-Resolution Laterolog Array resistivity for borehole and drilling mud
effects. RLA5 is the apparent resistivity from computed focusingmode 5.
*Mark of Schlumberger© Schlumberger
105
RLl
Resistivity Laterolog—LWD
GeoSteering* Bit Resistivity—6.75-in. ToolBorehole Correction—Open Hole RLl-20
PurposeThis chart is used to derive the borehole correction for the GeoSteeringbit-measured resistivity. The bit resistivity corrected to the trueresistivity (Rt) is then used in the calculation of water saturation.
DescriptionEnter the chart on the x-axis with the ratio of the bit resistivity andmud resistivity (Ra/Rm) at formation temperature. Move upward to
intersect the appropriate bit size. Move horizontally left to intersectthe correction factor on the y-axis. Multiply the correction factor bythe Ra value to obtain Rt. Charts RLl-21, RLl-23, and RLl-24 are simi-lar to Chart RLl-20 for different tools and bit sizes.
Chart RLl-22 differs in that it is for reaming-down mode asopposed to drilling mode.
0
0.5
0.7
0.8
0.9
1.1
1.2
1.0
10–2 10–1 100 101 102 103 104 105
Ra/Rm
Ra/Rm
24-in. bit18-in. bit12-in. bit
0.5
0.6
0.7
0.8
0.9
1.2
1.0
1.1
10–2 10–1 100 101 102 103 104 105
Rt/Ra
Rt/Ra
24-in. bit18-in. bit12-in. bit
*Mark of Schlumberger© Schlumberger
Resistivity Galvanic—DrillpipeResistivity Laterolog–LWD
106
RLl
GeoSteering* arcVISION675* Resistivity—6.75-in. ToolBorehole Correction—Open Hole RLl-21
10–2 10–1 100 101 102 103 104 105
Ra/Rm
0
0.5
0.7
0.8
0.9
1.1
1.2
1.0
0.5
0.6
0.7
0.8
0.9
1.2
1.0
1.1
10–2 10–1 100 101 102 103 104 105
Rt/Ra
Rt/Ra
Ra/Rm
24-in. bit18-in. bit12-in. bit
24-in. bit18-in. bit12-in. bit
PurposeThis chart is used similarly to Chart RLl-20 to derive the boreholecorrection for the GeoSteering bit-measured arcVISION675 resistivity.
*Mark of Schlumberger© Schlumberger
107
RLl
Resistivity Laterolog—LWD
GeoSteering* Bit Resistivity in Reaming Mode—6.75-in. ToolBorehole Correction—Open Hole RLl-22
PurposeThis chart is used similarly to Chart RLl-20 to derive the boreholecorrection for the GeoSteering bit-measured resistivity while ream-ing down.
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
10–2 10–1 100 101 102 103 104 105
Rt/Ra
Ra/Rm
arcVISION* tool
Bit
*Mark of Schlumberger© Schlumberger
Resistivity Laterolog—LWD
108
RLl
geoVISION* Resistivity Sub—6.75-in. ToolBorehole Correction—Open Hole RLl-23
2
1
Rt/Ra
100 101 102 103 104 105
Ra/Rm
Ring Resistivity (with 81⁄2-in. bit)2
1
Rt/Ra
100 101 102 103 104 105
Ra/Rm
Deep Button Resistivity (with 81⁄2-in. bit)
2
1
Rt/Ra
100 101 102 103 104 105
Ra/Rm Ra/Rm
Ra/Rm Ra/Rm
Medium Button Resistivity (with 81⁄2-in. bit)2
1
Rt/Ra
100 101 102 103 104 105
Shallow Button Resistivity (with 81⁄2-in. bit)
1
2
Rt/Ra
100 101 102 103 104 105
Bit Resistivity (with 81⁄2-in. bit) ROP to Bit Face = 4 ft 2
1
Rt/Ra
100 101 102 103 104 105
Bit Resistivity (with 81⁄2-in. bit) ROP to Bit Face = 35 ft
Borehole diameter (in.)
12
16
18
15
8.510
14
13
8.510
11
12
13
14
15
Borehole diameter (in.)
8.59.5
10.5
11
12
13
10
9.5
9.25
98.5
8.510
1214
16
18
2022
8.51012
1416
18
2022
Borehole diameter (in.)Borehole diameter (in.)
Borehole diameter (in.) Borehole diameter (in.)
PurposeThis chart is used similarly to Chart RLl-20 to derive the boreholecorrection for the bit-measured resistivity from the GVR* resistivity
sub of the geoVISION 6.75-in. tool. The bottom row of charts specifies the bit readout point (ROP) to the bit face.
*Mark of Schlumberger© Schlumberger
109
RLl
Resistivity Laterolog—LWD
geoVISION* Resistivity Sub—8.25-in. ToolBorehole Correction—Open Hole RLl-24
2
1
Rt/Ra
100 100
100 100
100 100
101 102 103 104 105
Ra/Rm
Ring Resistivity (with 121⁄4-in. bit)2
1
Rt /Ra
101 102 103 104 105
Ra/Rm
Deep Button Resistivity (with 121⁄4-in. bit)
2
1
Rt/Ra
101 102 103 104 105
Ra/Rm
Medium Button Resistivity (with 121⁄4-in. bit)2
1
Rt/Ra
101 102 103 104 105
Ra/Rm
Shallow Button Resistivity (with 121⁄4-in. bit)
1
2
Rt/Ra
101 102 103 104 105
Ra/Rm
Bit Resistivity (with 121⁄4-in. bit) ROP to Bit Face = 4 ft 2
1
Rt/Ra
101 102 103 104 105
Ra/Rm
Bit Resistivity (with 121⁄4-in. bit) ROP to Bit Face = 35 ft
22
12.2516
17
18
19
20
12.2514
15
16
1718
2019
12.2513.5
14
15
1617
12.25
12.75
13
13.5
14
12.2514
1618
20
2224
26
12.25141618
2022
2426
Borehole diameter (in.) Borehole diameter (in.)
Borehole diameter (in.) Borehole diameter (in.)
Borehole diameter (in.) Borehole diameter (in.)
PurposeThis chart is used similarly to Chart RLl-20 to derive the boreholecorrection for the bit-measured resistivity from the GVR* resistivity
sub of the geoVISION 8.25-in. tool. The bottom row of chartsspecifies the bit readout point (ROP) to the bit face.
*Mark of Schlumberger© Schlumberger
Resistivity Laterlog—LWD
110
RLl
GeoSteering* Bit Resistivity—6.75-in. ToolDistance Out of Formation—Open Hole RLl-25
10 ohm-m/4° BUR
100 ohm-m/4° BUR
10 ohm-m/5° BUR
100 ohm-m/5° BUR
10 ohm-m/10° BUR
600
500
400
300
200
100
0 0 2 4 6 8 10 12
Dip angle (°)
Distance (ft)
PurposeThis chart is used to calculate the distance the GeoSteering bit musttravel to return to the target formation.
DescriptionWhen drilling is at very high angles from vertical, the bit may wanderout of formation. If this occurs, how far the bit must travel to getback into the formation must be determined.
Enter the chart with the known dip angle of the formation on the x-axis. Move upward to intersect the appropriate “buildup rate”(BUR) curve. Move horizontally left from the intersection point tothe y-axis and read the distance back into the formation.
ExampleGiven: Formation dip angle = 6°, formation resistivity during
drilling = 10 ohm-m, and buildup rate = 4°.
Find: Distance to return to the target formation.
Answer: Enter the chart at 6° on the x-axis. Move upward to the10 ohm-m/4° BUR curve. Move horizontally left to the y-axis to read approximately 290 ft.
*Mark of Schlumberger© Schlumberger
111
RLl
GeneralResistivity Laterolog—Wireline
CHFR* Cased Hole Formation Resistivity ToolCement Correction—Cased Hole
RLl-50
PurposeThis chart is used to correct the raw cased hole resistivity measure-ment of the CHFR Cased Hole Formation Resistivity tool (Rchfr) forthe thickness of the cement sheath. The resulting value of true resis-tivity (Rt) is used to calculate the water saturation.
DescriptionEnter the chart on the x-axis with the ratio of Rchfr and the resistivityof the cement sheath (Rcem). The value of Rcem is obtained with labo-ratory measurements. Move upward to the appropriate cementsheath thickness curve, which represents the annular space betweenthe outside of the casing and the borehole wall. Move horizontallyleft to the y-axis and read the Rt/Rchfr value. Multiply this value byRchfr to obtain Rt.
Charts RLl-51 and RLl-52 are for making the correction in largercasing sizes.
No cement
0.5 in.
0.75 in.
1.5 in.
3 in.
5 in.
0
0.2
0.4
0.6
0.8
1.2
1.4
1.6
1.0
CHFR Cement Correction Chart (4.5-in.-OD casing)
10–2 10–1 100
Rchfr /Rcem
Rt /Rchfr
101 102
*Mark of Schlumberger© Schlumberger
General
112
RLl
Resistivity Laterolog—Wireline
0
0.2
0.4
0.6
0.8
1.2
1.4
1.6
1.0
CHFR Cement Correction Chart (7-in.-OD casing)
10–2 10–1 100
Rchfr/Rcem
Rt /Rchfr
101 102
No cement
0.5 in.
0.75 in.
1.5 in.
3 in.
5 in.
CHFR* Cased Hole Formation Resistivity ToolCement Correction—Cased Hole RLl-51
PurposeThis chart is used similarly to Chart RLl-50 to obtain the cased holeresistivity of the CHFR Cased Hole Formation Resistivity tool cor-rected for the thickness of the cement sheath in 7-in.-OD casing.
*Mark of Schlumberger© Schlumberger
113
RLl
Resistivity Laterolog—Wireline
CHFR* Cased Hole Formation Resistivity ToolCement Correction—Cased Hole RLl-52
No cement
0.5 in.
0.75 in.
1.5 in.
3 in.
5 in.
0
0.2
0.4
0.6
0.8
1.2
1.4
1.6
1.0
CHFR Cement Correction Chart (9.625-in.-OD casing)
10–2 10–1 100
Rchfr/Rcem
Rt/Rchfr
101 102
PurposeThis chart is used similarly to Chart RLl-50 to obtain the cased holeresistivity of the CHFR Cased Hole Formation Resistivity tool cor-rected for the thickness of the cement sheath in 9.625-in.-OD casing.
*Mark of Schlumberger© Schlumberger
Resistivity Galvanic—WirelineResistivity Induction—Wireline
114
RInd
AIT* Array Induction Imager ToolOperating Range—Open Hole
PurposeThis chart is used to determine the limit of application for the AITArray Induction Imager Tool measurement in a salt-saturated borehole.
DescriptionWhen the AIT tool logs a large salt-saturated borehole, the 10- and20-in. induction curves may well be unusable because of the largeconductive borehole. In a borehole with a diameter (dh) of 8 in., the 10- and 20-in. curve data are usable if Rt < 300Rm. The ratio of the true resistivity to the mud resistivity (Rt /Rm) is proportional to (dh/8)2.
A general rule is that a 12-in. borehole must have a ratio of Rt/Rm
≤ 133 to have usable shallow log data. Additional requirements arethat the borehole must be round and the AIT tool standoff is 2.5 in.The value of Rt/Rm is further reduced if the borehole is irregular orthe standoff requirement is not met.
Chart RInd-1 summarizes these requirements. The expected values of Rt, Rm, borehole size, and standoff size are entered to accurately determine the usable resolution in a smooth hole. Thelower chart summarizes which AIT resistivity tools typically providethe most accurate deep resistivity data.
Example: Salt-Saturated BoreholeGiven: Borehole size = 10 in., Rt = 5 ohm-m, Rm =
0.0135 ohm-m, and standoff (so) = 2.5 in.
Find: Which, if any, of the AIT curves are valid.
Answer: From the x-axis equation:
Enter the chart on the x-axis at 346 and move upward to intersect Rt = 5 ohm-m on the y-axis. The intersectionpoint is in an error zone for which the shallow inductioncurves are not valid even in a round borehole. Thedeeper induction curves are valid only with a 2-ft orlarger vertical resolution.
The limits for the 1-, 2-, and 4-ft curves are integral to the chart.As illustrated, a 1-ft 90-in. curve is not usable in a large salt-saturatedborehole. Also, under these conditions, the 1-, 2-, and 4-ft curves can-not have the same resistivity response.
Example: Freshwater Mud BoreholeGiven: Borehole size = 10 in., Rt = 5 ohm-m, Rm = 0.135 ohm-m,
and standoff (so) = 1.5 in.
Find: Which, if any, of the AIT curves are valid.
Answer: Rt/Rm = 37.0, (dh/8)2 = (10/8)2 = 1.5625, and (1.5/so) =1.5/1.5 = 1. The resulting value from the x-axis equationis 37.0 × 1.5625 × 1 = 57.9.
Enter the chart at 57.9 on the x-axis and intersect Rt = 5 ohm-m on the y-axis. The intersection point iswithin the limit of the 1-ft vertical resolution boundary.All the AIT induction curves are usable.
R
R
d
sot
m
h⎛
⎝⎜⎞
⎠⎟⎛
⎝⎜⎞
⎠⎟⎛⎝⎜
⎞⎠⎟
=8
1 52
.
50 0135
108
1 52 5
2
...
⎛⎝⎜
⎞⎠⎟
⎛⎝⎜
⎞⎠⎟
⎛⎝⎜
⎞⎠⎟
=
370 1 5625 0 6 346( )( )( ) =. . .
115
RInd
Resistivity Induction—Wireline
AIT* Array Induction Imager ToolOperating Range—Open Hole RInd-1
1,000
100
10
1
0.01 0.1 1 10 100 1,000 10,000 100,000
Limit of 4-ft logs
Possible large errors on all logs
Limit of 1-ft logs
Possible large errors on shallow logs and 2-ft limit
Recommended AIT operatingrange (compute standoffmethod for smooth holes)
RR
dht
m
⎛⎝⎜
⎞⎠⎟⎛⎝⎜
⎞⎠⎟
⎛⎝⎜
⎞⎠⎟8
1 52 .so
Rt(ohm-m)
Rt(ohm-m)
Salt-saturated boreholeexample
Freshwater mud example
10,000
1,000
100
1
0.01 0.1 1 10 100 1,000 10,000 100,000
Rt/Rm
AIT 2-ft limitAIT 4-ft limit
AIT 1-ft limit
AIT and HRLA*tools
AITtools
HRLAtools
*Mark of Schlumberger© Schlumberger
RInd
Resistivity Induction—Wireline
116
AIT* Array Induction Imager ToolBorehole Correction—Open Hole
IntroductionThe AIT tools (AIT-B, AIT-C, AIT-H, AIT-M, Slim Array InductionImager Tool [SAIT], Hostile Environment Induction Imager Tool[HIT], and SlimXtreme* Array Induction Imager Tool [QAIT]) do nothave chartbook corrections for environmental effects. The normaleffects that required correction charts in the past (borehole correc-tion, shoulder effect, and invasion interpretation) are now all madeusing real-time algorithms for the AIT tools. In reality, the charts forthe older dual induction tools were inadequate for the complexity ofenvironmental effects on induction tools. The very large volume ofinvestigation required to obtain an adequate radial depth of investiga-tion to overcome invasion makes the resulting set of charts too exten-sive for a book of this size. The volume that affects the logs can be tensof feet above and below the tool. To make useful logs, the effects of thevolume above and below the layer of interest must be carefully removed.This can be done only by either signal processing or inversion-basedprocessing. This section briefly describes the wellsite processing andadvanced processing available at computing centers.
Wellsite ProcessingBorehole CorrectionThe first step of AIT log processing is to correct the raw data from all eight arrays for borehole effects. Borehole corrections for the AITtools are based on inversion through an iterative forward model tofind the borehole parameters that best reproduce the logs from thefour shortest arrays—the 6-, 9-, 12-, and 15-in. arrays (Grove andMinerbo, 1991). The borehole forward model is based on a solutionto Maxwell’s equations in a cylindrical borehole of radius r with themud resistivity (Rm) surrounded by a homogeneous formation ofresistivity Rf. The tool can be located anywhere in the borehole, butis parallel to the borehole axis at a certain tool standoff (so). Theborehole is characterized by its radius (r). In this model, the signalin a given AIT array is a function of only these four parameters.
The four short arrays overlap considerably in their investigationdepth, so only two of the borehole parameters can be uniquely deter-mined in an inversion. The others must be supplied by outside mea-surements or estimates. Because the greatest sensitivity to theformation resistivity is in the contrast between Rm and Rf, no externalmeasurement is satisfactory for fitting to Rf. Therefore, Rf is alwayssolved for. This leaves one other parameter that can be determined.The three modes of the borehole correction operation depend onwhich parameter is being determined: compute mud resistivity: requires hole diameter and standoff
compute hole diameter: requires a mud resistivity measurementand standoff
compute standoff: requires hole diameter and mud resistivitymeasurement.
Because the AIT borehole model is a circular hole, either axisfrom a multiaxis caliper can be used. If the tool standoff is adequate,the process finds the circular borehole parameters that best matchthe input logs. Control of adequate standoff is important becausethe changes in the tool reading are very large for small changes intool position when the tool is very close to the borehole wall. Nearthe center of the hole the changes are very small. A table of rec-ommended standoff sizes is as follows.
Each type of AIT tool requires a slightly different approach tothe borehole correction method. For example, the AIT-B tool requiresthe use of an auxiliary Rm measurement (EnvironmentalMeasurement Sonde [EMS]) to compute Rm or to compute holesize by using a recalibration of the mud resistivity method internalto the borehole correction algorithm. The Platform Express*,SlimAccess*, and Xtreme* AIT tools have integral Rm sensors thatmeet the accuracy requirements for the compute standoff mode.
Log FormationAIT tools are designed to produce a high-resolution log responsewith reduced cave effect in comparison with the induction log deep(ILD) in most formations. The log processing (Barber and Rosthal,1991) is a weighted sum of the raw array data:
where σlog (z) is the output log conductivity in mS/m, σa(n) is the
skin-effect-corrected conductivity from the nth array, and theweights (w) represent a deconvolution filter applied to each of theraw array measurements. The log depth is z, and z′ refers to the distance above or below the log depth to where the weights areapplied. The skin effect correction consists of fitting the X-signal to the skin-effect-error signal (Moran, 1964; Barber, 1984) at highconductivities and the R-signal to the error signal at low conductivi-
σ σlogmin
max
z w z z zn
N
z z
z z
n an( ) = ′( ) − ′( )
= =
= ( )Σ Σ1
,,
AIT Tool Recommended StandoffHole Size (in.) Recommended Standoff (in.)
AIT-B, AIT-C, AIT-H, AIT-M, HIT SAIT, QAIT<5.0 – 0.55.0 to 5.5 – 1.0 5.5 to 6.5 0.5 1.5 6.5 to 7.75 1.0 2.0 7.75 to 9.5 1.5 2.5 9.5 to 11.5 2.0 + bowspring† 2.5 >11.5 2.5 + bowspring† 2.5 Note: Do not run AIT tools slick.
† Only for AIT-H tool
117
RInd
Resistivity Induction—Wireline
ties, with the crossover occurring between 100 and 200 mS/m. Theuse of the R-signal at low conductivities overcomes the errors inthe X-signal associated with the normal magnetic susceptibilities of sedimentary rock layers (Barber et al., 1995).
The weights w in the equation can profit from further refine-ment. The method used to compute the weights introduces a smallamount of noise in the matrix inversion, so the fit is about ±1% to±2% to the defined target response. A second refinement filter isused to correct for this error. The AIT wellsite processing sequence,from raw, calibrated data to corrected logs, is shown in Fig. 1.
There are only two versions of this processing—one for AIT-B,AIT-C, and AIT-D tools and one for all other AIT tools (AIT-H, AIT-M,SAIT, HIT, and QAIT) (Anderson and Barber, 1995). Only two ver-sions are required because the tools were carefully designed withthe same coil spacings to produce the same two-dimensional (2D)response to the formation.
Advanced ProcessingLogs in Deviated Wells or Dipping FormationsThe interpretation of induction logs is complicated by the large vol-ume of investigation of these tools. The AIT series of induction toolsis carefully focused to limit the contributions from outside a rela-tively thin layer of response (Barber and Rosthal, 1991). In beds at high relative dip, the focused response cuts across several beds,and the focusing developed for vertical wells no longer isolates theresponse to a single layer. The effect of the high relative dip angle is to blur the response and to introduce horns at the bed boundaries.
Maximum Entropy Inversion: MERLIN ProcessingThe maximum entropy inversion method was first applied by Dyos(1987) to induction log data. For beds at zero dip angle, it has beenshown to give well-controlled results when applied to deep induction(ID) and medium induction (IM) from the dual induction tool
(Freedman and Minerbo, 1991, 1993; Zhang et al., 1994). Maximum-Entropy Resistivity Log Inversion (MERLIN) processing (Barber etal., 1999) follows Freedman and Minerbo (1991) closely, and thatpaper is the basic reference for the mathematical formulation. Theproblem is set up as the simplest parametric model that can fit thedata: a thinly layered formation with each layer the same thickness(Fig. 2). The inversion problem is to solve for the conductivity ofeach layer so that the computed logs from the layered formation are the closest match to the measured logs.
AIT* Array Induction Imager ToolBorehole Correction—Open Hole
Rn
R1
yxφ
ρ
z
θ
Well path
∆z
Figure 2. The parametric model used in MERLIN inversion. All layers are thesame thickness, and the inversion solves for the conductivity of each layerwith maximum-entropy constraints.
10 in.20 in.30 in.60 in.90 in.
28 channels(AIT-B, -C, and -D)16 channels(all others)
Skineffect
correction
Multichannelsignal
processingand 2D
processing
14or8
28or16
Boreholecorrection
Caliper
Rm
Standoff
A(H)IFC
R-signals only
R-signalsX-signals
28or16
Five depths(10 to 90 in.)
Five depths(10 to 90 in.)
Exceptionhandling and
environmentallycompensatedlog processing
Rm
Caliper
Raw BHC signals
+
Figure 1. Block diagram of the real-time log processing chain from raw, calibrated array data to finished logs.
Rxo
Rxo
Rt
Rt
ri
Formationresistivity
profile
Distance from wellbore
Step Profile
Distance from wellbore
Slope Profile
Annulus Profile
Rt
Rann
Rxo
r1
r2
r1
r2
118
RInd
Resistivity Induction—Wireline
AIT* Array Induction Imager ToolBorehole Correction—Open Hole
Figure 4. Parametric models used in AIT invasion processing. The slopeprofile model is used for real-time processing; the others are available at the computing centers. Rxo = resistivity of the flushed zone, Rt = trueresistivity, ri = radius of invasion, Rann = resistivity of the annulus.
Borehole-corrected R- and X-signals
Model parameters
Sensitivitymatrix
Update modelparameters
Yes
No
ExitWrite modelparameters
as log
28 or 16 channels
Computedlog within 1% of measured
log?
Computed log
Forward model
Initial guess
ComputeLagrangian
Figure 3. Data flow in the MERLIN inversion algorithm. The output is thefinal set of model parameters after the iterations converge.
The flow of MERLIN processing is shown in Fig. 3. The borehole-corrected raw resistive and reactive (R- and X-) signals are used as a starting point. The conductivity of a set of layers is estimated fromthe log values, and the iterative modeling is continued until the logsconverge. The set of formation layer conductivity values is then con-verted to resistivity and output as logs.
Invasion ProcessingThe wellsite interpretation for invasion is a one-dimensional (1D)inversion of the processed logs into a four-parameter invasion model(Rxo, Rt, r1, and r2, shown in Fig. 4). The forward model is based onthe Born model of the radial response of the tools and is accurate formost radial contrasts in which induction logs should be used. Theinversion can be run in real time. The model is also available in theInvasion Correction module of the GeoFrame* Invasion 2 application,which also includes the step-invasion model and annulus model (Fig. 4).
119
RInd
Resistivity Induction—Wireline
AIT* Array Induction Imager ToolBorehole Correction—Open Hole
Rt0
∞
∞
Rt1
Rt2
Rxo1
Rxo2
Rm
Rm
Another approach is also used in the Invasion 2 application mod-ule. If the invaded zone is more conductive than the noninvadedzone, some 2D effects on the induction response can complicatethe 1D inversion. Invasion 2 conducts a full 2D inversion using a2D forward model (Fig. 5) to produce a more accurate answer forsituations of conductive invasion and in thin beds.
ReferencesAnderson, B., and Barber, T.: Induction Logging, Sugar Land, TX,USA, Schlumberger SMP-7056 (1995).
Barber, T.D.: “Phasor Processing of Induction Logs IncludingShoulder and Skin Effect Correction,” US Patent No. 4,513,376(September 11, 1984).
Barber, T., et al.: “Interpretation of Multiarray Induction Logs inInvaded Formations at High Relative Dip Angles,” The Log Analyst,(May–June 1999) 40, No. 3, 202–217.
Barber, T., Anderson, B., and Mowat, G.: “Using Induction Tools toIdentify Magnetic Formations and to Determine Relative MagneticSusceptibility and Dielectric Constant,” The Log Analyst(July–August 1995) 36, No. 4, 16–26.
Barber, T., and Rosthal, R.: “Using a Multiarray Induction Tool toAchieve Logs with Minimum Environmental Effects,” paper SPE 22725presented at the SPE Annual Technical Conference and Exhibition,Dallas, Texas, USA (October 6–9, 1991).
Dyos, C.J.: “Inversion of the Induction Log by the Method of MaximumEntropy,” Transactions of the SPWLA 28th Annual LoggingSymposium, London, UK (June 29–July 2, 1987), paper T.
Freedman, R., and Minerbo, G.: “Maximum Entropy Inversion of theInduction Log,” SPE Formation Evaluation (1991), 259–267; alsopaper SPE 19608 presented at the SPE Annual Technical Conferenceand Exhibition, San Antonio, TX, USA (October 8–11, 1989).
Freedman, R., and Minerbo, G.: “Method and Apparatus forProducing a More Accurate Resistivity Log from Data Recorded by anInduction Sonde in a Borehole,” US Patent 5,210,691 (January 1993).
Grove, G.P., and Minerbo, G.N.: “An Adaptive Borehole CorrectionScheme for Array Induction Tools,” Transactions of the SPWLA 32ndAnnual Logging Symposium, Midland, Texas, USA (June 16–19,1991), paper P.
Moran, J.H.: “Induction Method and Apparatus for InvestigatingEarth Formations Utilizing Two Quadrature Phase Components of a Detected Signal,” US Patent No. 3,147,429 (September 1, 1964).
Zhang, Y-C., Shen, L., and Liu, C.: “Inversion of Induction Logs Basedon Maximum Flatness, Maximum Oil, and Minimum Oil Algorithms,”Geophysics (September 1994), 59, No. 9, 1320–1326.
Figure 5. The parametric 2D formation model used in Invasion 2.
arcVISION475* and ImPulse* 43⁄4-in. Drill Collar Resistivity Tools—2 MHzBorehole Correction—Open Hole
Resistivity Electromagnetic—LWD
PurposeThis chart is used to determine the borehole correction applied by the surface acquisition system to arcVISION475 and ImPulsephase-shift (Rps) and attenuation resistivity (Rad) curves on the log. The value of Rt is used in the calculation of water saturation.
DescriptionEnter the appropriate chart for the borehole environmental condi-tions and tool used to measure the various formation resistivitieswith the either the uncorrected phase-shift or attenuation resistivityvalue (not the resistivity shown on the log) on the x-axis. Move upwardto intersect the appropriate resistivity spacing line, and then movehorizontally left to read the ratio value on the y-axis. Multiply theratio value by the resistivity value entered on the x-axis to obtain Rt.
Charts REm-12 through REm-38 are used similarly to ChartREm-11 for different borehole conditions and arcVISION* andImPulse tool combinations.
ExampleGiven: Rps = 400 ohm-m (uncorrected) from arcVISION475
(2-MHz) phase-shift 10-in. resistivity, borehole size = 6 in., and mud resistivity (Rm) = 0.02 ohm-m at forma-tion temperature.
Find: Formation resistivity (Rt).
Answer: Enter the top left chart at 400 ohm-m on the x-axis and move upward to intersect the 10-in. resistivity curve (green).
Move left and read approximately 1.075 on the y-axis.
Rt = 1.075 × 400 = 430 ohm-m.
REm
120
121
Resistivity Electromagnetic—LWD
REm
arcVISION475* and ImPulse* 43⁄4-in. Drill Collar Resistivity Tools—2 MHzBorehole Correction—Open Hole REm–11
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 6 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 6 in., Rm = 0.1 ohm-m
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 6 in., Rm = 1.0 ohm-m
10 2816 3422Resistivity spacing (in.)
*Mark of Schlumberger© Schlumberger
arcVISION475* and ImPulse* 43⁄4-in. Drill Collar Resistivity Tools—2 MHzBorehole Correction—Open Hole REm-12
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 7 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 7 in., Rm = 0.1 ohm-m
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 7 in., Rm = 1.0 ohm-m
281610 3422Resistivity spacing (in.)
Resistivity Electromagnetic—LWD
122
REm
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION475 and ImPulse resistivity measurements. Uncorrectedresistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
Resistivity Electromagnetic—LWD
123
REm
arcVISION475* and ImPulse* 43⁄4-in. Drill Collar Resistivity Tools—2 MHzBorehole Correction—Open Hole REm-13
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 8 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rt /Rps Rt /Rad
Rt /Rps Rt /Rad
Rt /Rps Rt /Rad
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 8 in., Rm = 0.1 ohm-m
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 8 in., Rm = 1.0 ohm-m
281610 3422Resistivity spacing (in.)
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION475 and ImPulse resistivity measurements. Uncorrectedresistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
Resistivity Electromagnetic—LWD
124
REm
arcVISION475* and ImPulse* 43⁄4-in. Drill Collar Resistivity Tools—2 MHzBorehole Correction—Open Hole REm-14
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 10 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 10 in., Rm = 0.1 ohm-m
arcVISION475 and ImPulse Borehole Correction for 2 MHz, dh = 10 in., Rm = 1.0 ohm-m
281610 3422Resistivity spacing (in.)
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION475 and ImPulse resistivity measurements. Uncorrectedresistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
Resistivity Electromagnetic—LWD
125
REm
arcVISION675* 63⁄4-in. Drill Collar Resistivity Tool—400 kHzBorehole Correction—Open Hole REm-15
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 400 kHz, dh = 8 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
arcVISION675 Borehole Correction for 400 kHz, dh = 8 in., Rm = 0.1 ohm-m
arcVISION675 Borehole Correction for 400 kHz, dh = 8 in., Rm = 1.0 ohm-m
342216 4028Resistivity spacing (in.)
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION675 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
Resistivity Electromagnetic—LWD
126
REm
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 400 kHz, dh = 10 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
arcVISION675 Borehole Correction for 400 kHz, dh = 10 in., Rm = 0.1 ohm-m
arcVISION675 Borehole Correction for 400 kHz, dh = 10 in., Rm = 1.0 ohm-m
Resistivity spacing (in.) 342216 4028
arcVISION675* 63⁄4-in. Drill Collar Resistivity Tool—400 kHzBorehole Correction—Open Hole REm-16
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION675 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
General
127
REm
Resistivity Electromagnetic—LWD
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 400 kHz, dh = 12 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
arcVISION675 Borehole Correction for 400 kHz, dh = 12 in., Rm = 0.1 ohm-m
arcVISION675 Borehole Correction for 400 kHz, dh = 12 in., Rm = 1.0 ohm-m
342216 4028Resistivity spacing (in.)
arcVISION675* 63⁄4-in. Drill Collar Resistivity Tool—400 kHzBorehole Correction—Open Hole REm-17
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION675 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
128
REm
Resistivity Electromagnetic—LWD
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 400 kHz, dh = 14 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
arcVISION675 Borehole Correction for 400 kHz, dh = 14 in., Rm = 0.1 ohm-m
arcVISION675 Borehole Correction for 400 kHz, dh = 14 in., Rm = 1.0 ohm-m
342216 4028Resistivity spacing (in.)
arcVISION675* 63⁄4-in. Drill Collar Resistivity Tool—400 kHzBorehole Correction—Open Hole REm-18
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION675 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
129
Resistivity Electromagnetic—LWD
REm
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 2 MHz, dh = 8 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
arcVISION675 Borehole Correction for 2 MHz, dh = 8 in., Rm = 0.1 ohm-m
arcVISION675 Borehole Correction for 2 MHz, dh = 8 in., Rm = 1.0 ohm-m
342216 4028Resistivity spacing (in.)
arcVISION675* 63⁄4-in. Drill Collar Resistivity Tool—2 MHzBorehole Correction—Open Hole REm-19
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION675 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
130
REm
Resistivity Electromagnetic—LWD
Resistivity spacing (in.) 342216 4028
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 2 MHz, dh = 10 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
arcVISION675 Borehole Correction for 2 MHz, dh = 10 in., Rm = 0.1 ohm-m
arcVISION675 Borehole Correction for 2 MHz, dh = 10 in., Rm = 1.0 ohm-m
arcVISION675* 63⁄4-in. Drill Collar Resistivity Tool—2 MHzBed Thickness Correction—Open Hole REm-20
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION675 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
131
REm
Resistivity Electromagnetic—LWD
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 2 MHz, dh = 12 in., Rm = 0.05 ohm-m
10–1
10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
arcVISION675 Borehole Correction for 2 MHz, dh = 12 in., Rm = 0.1 ohm-m
arcVISION675 Borehole Correction for 2 MHz, dh = 12 in., Rm = 1.0 ohm-m
342216 4028Resistivity spacing (in.)
arcVISION675* 63⁄4-in. Drill Collar Resistivity Tool—2 MHzBorehole Correction—Open Hole REm-21
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION675 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
Resistivity Electromagnetic—LWD
132
REm
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
1.0
2.0
1.5
0.5
arcVISION675 Borehole Correction for 2 MHz, dh = 14 in., Rm = 0.02 ohm-m
10–1
10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103
100 101 102 103 10–1 100 101 102 103
Rps (ohm-m)
Rps (ohm-m)
Rps (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rad (ohm-m)
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
Rt/Rps Rt/Rad
arcVISION675 Borehole Correction for 2 MHz, dh = 14 in., Rm = 0.1 ohm-m
arcVISION675 Borehole Correction for 2 MHz, dh = 14 in., Rm = 1.0 ohm-m
342216 4028Resistivity spacing (in.)
arcVISION675* 63⁄4-in. Drill Collar Resistivity Tool—2 MHzBorehole Correction—Open Hole REm-22
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION675 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
133
REm
Resistivity Electromagnetic—LWD
arcVISION825* 81⁄4-in. Drill Collar Resistivity Tool—400 kHzBorehole Correction—Open Hole REm-23
arcVISION825 Borehole Correction for 400 kHz, dh = 10 in., Rm = 0.02 ohm-m
arcVISION825 Borehole Correction for 400 kHz, dh = 10 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
arcVISION825 Borehole Correction for 400 kHz, dh = 10 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 101 102 103 10–1 100 101 102 103 100
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION825 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
134
REm
Resistivity Electromagnetic—LWD
arcVISION825* 81⁄4-in. Drill Collar Resistivity Tool—400 kHzBed Thickness Correction—Open Hole REm-24
arcVISION825 Borehole Correction for 400 kHz, dh = 12 in., Rm = 0.02 ohm-m
arcVISION825 Borehole Correction for 400 kHz, dh = 12 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
arcVISION825 Borehole Correction for 400 kHz, dh = 12 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION825 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
135
REm
Resistivity Electromagnetic—LWD
arcVISION825* 81⁄4-in. Drill Collar Resistivity Tool—400 kHzBorehole Correction—Open Hole REm-25
arcVISION825 Borehole Correction for 400 kHz, dh = 14 in., Rm = 0.02 ohm-m
arcVISION825 Borehole Correction for 400 kHz, dh = 14 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
arcVISION825 Borehole Correction for 400 kHz, dh = 14 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION825 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
136
REm
Resistivity Electromagnetic—LWD
arcVISION825* 81⁄4-in. Drill Collar Resistivity Tool—400 kHzBorehole Correction—Open Hole REm-26
arcVISION825 Borehole Correction for 400 kHz, dh = 18 in., Rm = 0.02 ohm-m
arcVISION825 Borehole Correction for 400 kHz, dh = 18 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
arcVISION825 Borehole Correction for 400 kHz, dh = 18 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION825 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
137
REm
Resistivity Electromagnetic—LWD
arcVISION825* 81⁄4-in. Drill Collar Resistivity Tool—2 MHzBorehole Correction—Open Hole REm-27
arcVISION825 Borehole Correction for 2 MHz, dh = 10 in., Rm = 0.02 ohm-m
arcVISION825 Borehole Correction for 2 MHz, dh = 10 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
arcVISION825 Borehole Correction for 2 MHz, dh = 10 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION825 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
138
REm
Resistivity Electromagnetic—LWD
arcVISION825* 81⁄4-in. Drill Collar Resistivity Tool—2 MHzBorehole Correction—Open Hole REm-28
arcVISION825 Borehole Correction for 2 MHz, dh = 12 in., Rm = 0.02 ohm-m
arcVISION825 Borehole Correction for 2 MHz, dh = 12 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
arcVISION825 Borehole Correction for 2 MHz, dh = 12 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 10310–1 100 101 102 103
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION825 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
139
REm
Resistivity Electromagnetic—LWD
arcVISION825* 81⁄4-in. Drill Collar Resistivity Tool—2 MHzBorehole Correction—Open Hole REm-29
arcVISION825 Borehole Correction for 2 MHz, dh = 14 in., Rm = 0.02 ohm-m
arcVISION825 Borehole Correction for 2 MHz, dh = 14 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
arcVISION825 Borehole Correction for 2 MHz, dh = 14 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 10310–1 100 101 102 103
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION825 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
140
REm
Resistivity Electromagnetic—LWD
arcVISION825* 81⁄4-in. Drill Collar Resistivity Tool—2 MHzBorehole Correction—Open Hole REm-30
arcVISION825 Borehole Correction for 2 MHz, dh = 18 in., Rm = 0.02 ohm-m
arcVISION825 Borehole Correction for 2 MHz, dh = 18 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rad (ohm-m)
arcVISION825 Borehole Correction for 2 MHz, dh = 18 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 10310–1 100 101 102 103
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION825 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
141
REm
Resistivity Electromagnetic—LWD
arcVISION900* 9-in. Drill Collar Resistivity Tool—400 kHzBorehole Correction—Open Hole REm-31
arcVISION900 Borehole Correction for 400 kHz, dh = 12 in., Rm = 0.02 ohm-m
arcVISION900 Borehole Correction for 400 kHz, dh = 12 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
arcVISION900 Borehole Correction for 400 kHz, dh = 12 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION900 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
142
REm
Resistivity Electromagnetic—LWD
arcVISION900* 9-in. Drill Collar Resistivity Tool—400 kHzBorehole Correction—Open Hole REm-32
arcVISION900 Borehole Correction for 400 kHz, dh = 15 in., Rm = 0.02 ohm-m
arcVISION900 Borehole Correction for 400 kHz, dh = 15 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
arcVISION900 Borehole Correction for 400 kHz, dh = 15 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION900 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
143
REm
Resistivity Electromagnetic—LWD
arcVISION900* 9-in. Drill Collar Resistivity Tool—400 kHzBorehole Correction—Open Hole REm-33
arcVISION900 Borehole Correction for 400 kHz, dh = 18 in., Rm = 0.02 ohm-m
arcVISION900 Borehole Correction for 400 kHz, dh = 18 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
arcVISION900 Borehole Correction for 400 kHz, dh = 18 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 10310–1 100 101 102 103
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION900 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
144
REm
Resistivity Electromagnetic—LWD
arcVISION900* 9-in. Drill Collar Resistivity Tool—400 kHzBorehole Correction—Open Hole REm-34
arcVISION900 Borehole Correction for 400 kHz, dh = 22 in., Rm = 0.02 ohm-m
arcVISION900 Borehole Correction for 400 kHz, dh = 22 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
arcVISION900 Borehole Correction for 400 kHz, dh = 22 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION900 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
145
REm
Resistivity Electromagnetic—LWD
arcVISION900* 9-in. Drill Collar Resistivity Tool—2 MHzBorehole Correction—Open Hole REm-35
arcVISION900 Borehole Correction for 2 MHz, dh = 12 in., Rm = 0.02 ohm-m
arcVISION900 Borehole Correction for 2 MHz, dh = 12 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
arcVISION900 Borehole Correction for 2 MHz, dh = 12 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 103 10–1 100 101 102 103
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION900 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
146
REm
Resistivity Electromagnetic—LWD
arcVISION900* 9-in. Drill Collar Resistivity Tool—2 MHzBorehole Correction—Open Hole REm-36
arcVISION900 Borehole Correction for 2 MHz, dh = 15 in., Rm = 0.02 ohm-m
arcVISION900 Borehole Correction for 2 MHz, dh = 15 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
arcVISION900 Borehole Correction for 2 MHz, dh = 15 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 10310–1 100 101 102 103
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION900 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
147
REm
Resistivity Electromagnetic—LWD
arcVISION900* 9-in. Drill Collar Resistivity Tool—2 MHzBorehole Correction—Open Hole REm-37
arcVISION900 Borehole Correction for 2 MHz, dh = 18 in., Rm = 0.02 ohm-m
arcVISION900 Borehole Correction for 2 MHz, dh = 18 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
arcVISION900 Borehole Correction for 2 MHz, dh = 18 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 10310–1 100 101 102 103
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION900 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
148
REm
Resistivity Electromagnetic—LWD
arcVISION900* 9-in. Drill Collar Resistivity Tool—2 MHzBorehole Correction—Open Hole REm-38
arcVISION900 Borehole Correction for 2 MHz, dh = 22 in., Rm = 0.02 ohm-m
arcVISION900 Borehole Correction for 2 MHz, dh = 22 in., Rm = 0.1 ohm-m
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
10–1 100 101 102 103
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
arcVISION900 Borehole Correction for 2 MHz, dh = 22 in., Rm = 1.0 ohm-m2.0
1.5
1.0
0.5
Rt/Rps
Rps (ohm-m)
2.0
1.5
1.0
0.5
Rt/Rad
Rad (ohm-m)
10–1 100 101 102 103 10–1 100 101 102 103
10–1 100 101 102 10310–1 100 101 102 103
Resistivity spacing (in.) 342216 4028
PurposeThis chart is used similarly to Chart REm-11 to determine the borehole correction applied by the surface acquisition system
to arcVISION900 resistivity measurements. Uncorrected resistivity is entered on the x-axis, not the resistivity shown on the log.
*Mark of Schlumberger© Schlumberger
149
REm
Resistivity Electromagnetic—LWD
PurposeThis chart is used to determine the correction factor applied by thesurface acquisition system for bed thickness to the phase-shift andattenuation resistivity on the logs of arcVISION675, arcVISION825,and arcVISION900 tools.
DescriptionThe six bed thickness correction charts on this page are paired forphase-shift and attenuation resistivity at different values of true (Rt)and shoulder bed (Rs) resistivity. Only uncorrected resistivity valuesare entered on the chart, not the resistivity shown on the log.
Chart REm-56 is also used to find the bed thickness correctionapplied by the surface acquisition system for 2-MHz arcVISION* andImPulse* logs.
ExampleGiven: Rt/Rs = 10/1, Rps uncorrected = 20 ohm-m (34 in.), and
bed thickness = 6 ft.
Find: Rt.
Answer: The appropriate chart to use is the phase-shift resistivitychart in the first row, for Rt = 10 ohm-m and Rs = 1 ohm-m.
Enter the chart on the x-axis at 6 ft and move upward to intersect the 34-in. spacing line. The correspondingvalue of Rt/Rps is 1.6; Rt = 20 × 1.6 = 32 ohm-m.
arcVISION675*, arcVISION825*, and arcVISION900* Array Resistivity Compensated Tools—400 KHzBed Thickness Correction—Open Hole
continued on next page
arcVISION675*, arcVISION825*, and arcVISION900* Array Resistivity Compensated Tools—400 kHzBed Thickness Correction—Open Hole
REm-55
Phase-Shift Resistivity Attenuation Resistivity
Attenuation Resistivity
arcVISION675, arcVISION825, and arcVISION900 400-kHz Bed Thickness Correction for Rt = 10 ohm-m and Rs = 1 ohm-m at Center of Bed
0 2 4 6 8 10 12 14 16
2.0
1.5
1.0
0.5
0
Rt/Rps Rt/Rad
Bed thickness (ft)
0 2 4 6 8 10 12 14 16
2.0
1.5
1.0
0.5
0
Bed thickness (ft)
Phase-Shift Resistivity
arcVISION675, arcVISION825, and arcVISION900 400-kHz Bed Thickness Correction for Rt = 1 ohm-m and Rs =10 ohm-m at Center of Bed
0 2 4 6 8 10 12 14 16
2.0
1.5
1.0
0.5
0
Rt/Rps Rt/Rad
Bed thickness (ft)
0 2 4 6 8 10 12 14 16
2.0
1.5
1.0
0.5
0
Bed thickness (ft)
Phase-Shift Resistivity
arcVISION675, arcVISION825, and arcVISION900 400-kHz Bed Thickness Correction for Rt = 100 ohm-m and Rs =10 ohm-m at Center of Bed
0 2 4 6 8 10 12 14 16
2.0
1.5
1.0
0.5
0
Rt/Rps
Bed thickness (ft)
Resistivity spacing (in.) 342216 4028
150
REm
Resistivity Electromagnetic—LWD
*Mark of Schlumberger© Schlumberger
151
REm
Resistivity Electromagnetic—LWD
arcVISION* and ImPulse* Array Resistivity Compensated Tools—2 MHzBed Thickness Correction—Open Hole REm-56
Phase-Shift Resistivity Attenuation Resistivity
Attenuation Resistivity
arcVISION and ImPulse 2-MHz Bed Thickness Correction for Rt = 10 ohm-m and Rs =1 ohm-m at Center of Bed
0 2 4 6 8 10 12 14 16
2.0
1.5
1.0
0.5
0
Rt/Rps Rt/Rad
Bed thickness (ft)
0 2 4 6 8 10 12 14 16
2.0
1.5
1.0
0.5
0
Bed thickness (ft)
Phase-Shift Resistivity
arcVISION and ImPulse 2-MHz Bed Thickness Correction forRt = 1 ohm-m and Rs =10 ohm-m at Center of Bed
0 2 4 6 8 10 12 14 16
2.0
1.5
1.0
0.5
0
Rt/Rps Rt/Rad
Bed thickness (ft)
0 2 4 6 8 10 12 14 16
2.0
1.5
1.0
0.5
0
Bed thickness (ft)
Attenuation ResistivityPhase-Shift Resistivity
arcVISION and ImPulse 2-MHz Bed Thickness Correction forRt = 100 ohm-m and Rs =10 ohm-m at Center of Bed
0 2 4 6 8 10 12 14 16
2.0
1.5
1.0
0.5
0
Rt/Rps Rt/Rad
Bed thickness (ft)
0 2 4 6 8 10 12 14 16
2.0
1.5
1.0
0.5
0
Bed thickness (ft)
Resistivity spacing (in.) 342216 4028*Mark of Schlumberger© Schlumberger
Resistivity Electromagnetic—LWD
152
REm
arcVISION675* and ImPulse* Array Resistivity Compensated Tools—2 MHz and 16-in. SpacingDielectric Correction—Open Hole
REm-58
PurposeThis chart is used to estimate the true resistivity (Rt) and dielectriccorrection (εr). Rt is used in water saturation calculation.
DescriptionEnter the chart with the uncorrected (not those shown on the log)phase-shift and attenuation values from the arcVISION675 orImPulse resistivity tool. The intersection point of the two values isused to determine Rt and the dielectric correction. Rt is interpolatedfrom the subvertical lines described by the dots originating at the
listed Rt values. The εr is interpolated from the radial lines originatingfrom the εr values listed on the left-hand side of the chart. ChartsREm-59 through REm-62 are used to determine Rt and εr at largerspacings.
ExampleGiven: Phase shift = 2° and attenuation = 8.45 dB for 16-in.
spacing.
Find: Rt and εr.
Answer: Rt = 26 ohm-m and εr = 70 dB.
–1 0 1 2 3 4 5 6 7 8 98.10
8.15
8.20
8.25
8.30
8.35
8.40
8.45
8.50
8.55
8.60
Phase shift (°)
Attenuation(dB)
1102030405060708090100
125
150
175
200
225
250
275
300
30
50
7010
0
15
20
1,00
010
,000
R to
*Mark of Schlumberger© Schlumberger
153
REm
Resistivity Electromagnetic—LWD
PurposeCharts REm-59 through REm-62 are identical to Chart REm-58 for determining Rt and εr at larger spacings of the arcVISION675 and ImPulse 2-MHz tools.
arcVISION675* and ImPulse* Array Resistivity Compensated Tools—2 MHz and 22-in. SpacingDielectric Correction—Open Hole
REm-59
–1 0 1 2 3 4 5 6 7 8 96.3
6.4
6.5
6.6
6.7
6.8
6.9
Phase shift (°)
Attenuation(dB)
1
10
20
30
40
50
60
70
80
90
100
125
150
175
200
225
250
275
300
30
50
70
100
15
20
1,00
010
,000
o
R t
*Mark of Schlumberger© Schlumberger
PurposeCharts REm-59 through REm-62 are identical to Chart REm-58 for determining Rt and εr at larger spacings of the arcVISION675and ImPulse 2-MHz tools.
154
REm
Resistivity Electromagnetic—LWD
arcVISION675* and ImPulse* Array Resistivity Compensated Tools—2 MHz and 28-in. SpacingDielectric Correction—Open Hole
REm-60
o
–1 0 1 2 3 4 5 6 7 8 9
4.9
4.8
5.0
5.1
5.2
5.3
5.4
5.5
Phase shift (°)
Attenuation(dB)
1
10
20
30
40
50
60
70
80
90
100
125
150
175
200
225
250
275
300
30
50
70
100
20
1,00
010
,000
R to
*Mark of Schlumberger© Schlumberger
155
REm
Resistivity Electromagnetic—LWD
arcVISION675* and ImPulse* Array Resistivity Compensated Tools—2 MHz and 34-in. SpacingDielectric Correction—Open Hole
REm-61
–1 0 1 2 3 4 5 6 7 8 9
4.0
3.9
4.2
4.1
4.3
4.4
4.5
4.6
4.7
Phase shift (°)
Attenuation(dB)
1
10
20
30
40
50
60
70
80
90
100
125
150
175
200
225
250
275
300
30
50
70
100
15
20
1,00
010
,000
o
R t
PurposeCharts REm-59 through REm-62 are identical to Chart REm-58 for determining Rt and εr at larger spacings of the arcVISION675and ImPulse 2-MHz tools.
*Mark of Schlumberger© Schlumberger
156
REm
Resistivity Electromagnetic—LWD
arcVISION675* and ImPulse* Array Resistivity Compensated Tools—2 MHz and 40-in. SpacingDielectric Correction—Open Hole
REm-62
–1 0 1 2 3 4 5 6 7 8 93.1
3.2
3.3
3.4
3.5
3.6
3.7
3.8
3.9
4.0
Phase shift (°)
Attenuation(dB)
1
10
20
30
40
50
60
70
80
90
100
125
150
175
200
225
250
275
300
30
50
70
100
15
20
1,00
010
,000
R to
PurposeCharts REm-59 through REm-62 are identical to Chart REm-58 fordetermining Rt and εr at larger spacings of the arcVISION675 andImPulse 2-MHz tools.
*Mark of Schlumberger© Schlumberger
157
REm
Resistivity Electromagnetic—LWD
arcVISION675* and ImPulse* Array Resistivity Compensated Tools—2 MHz with Dielectric AssumptionDielectric Correction—Open Hole
REm-63
10–1
1.0
1.5
2.0
2.5
3.0
3.5
Dielectric Effects of Standard Processed arcVISION675 or ImPulse Logat 2 MHz with Dielectric Assumption
100 101 102 103 104
Rt/Rps
Rps (ohm-m)
10–1
1.0
1.5
2.0
2.5
3.0
3.5
100 101 102 103 104
Rt/Rad
Rad (ohm-m)
0.5
0.5
16 in.22 in.28 in.34 in.40 in.
Resistivityspacing
16 in.22 in.28 in.34 in.40 in.
Resistivityspacing
Dielectric assumptionεr = 5 + 108.5R–0.35
ε1 = 2εr
Dielectric assumptionεr = 5 + 108.5R–0.35
ε2 = 0.5εr
ε2 = 0.5εr
ε1 = 2εr
oo
*Mark of Schlumberger© Schlumberger
General
158
Formation Resistivity—Wireline
Resistivity GalvanicInvasion Correction—Open Hole Rt-1
(former Rint-1)
Rt
PurposeThe charts in this chapter are used to determine the correction forinvasion effects on the following parameters:
diameter of invasion (di) ratio of flushed zone to true resistivity (Rxo/Rt) Rt from laterolog resistivity tools.
The Rxo/Rt and Rt values are used in the calculation of water saturation.
DescriptionThe invasion correction charts, also referred to as “tornado” or “but-terfly” charts, assume a step-contact profile of invasion and that allresistivity measurements have already been corrected as necessaryfor borehole effect and bed thickness by using the appropriate chartfrom the “Resistivity Laterolog” chapter.
To use any of these charts, enter the y-axis and x-axis with therequired resistivity ratios. The point of intersection defines di,Rxo/Rt, and Rt as a function of one resistivity measurement.
Saturation Determination in Clean FormationsEither of the chart-derived values of Rt and Rxo/Rt are used to findvalues for the water saturation of the formation (Sw). The first of twoapproaches is the Sw-Archie (SwA), which is found using the Archiesaturation formula (or Chart SatOH-3) with the derived Rt value andknown values of the formation resistivity factor (FR) and the resistiv-ity of the water (Rw). The Sw-ratio (SwR) is found by using Rxo/Rt andRmf/Rw as in Chart SatOH-4.
If SwA and SwR are equal, the assumption of a step-contact inva-sion profile is indicated to be correct, and all values determined (Sw, Rt, Rxo, and di) are considered good.
If SwA > SwR, either invasion is very shallow or a transition-type invasion profile is indicated, and SwA is considered a good value for Sw.
If SwA < SwR, an annulus-type invasion profile may be indicated,and a more accurate value of water saturation may be estimated by using
The correction factor of (SwA /SwR)1 ⁄4 is readily determined fromthe scale.
For more information, see Reference 9.
(SwA/SwR) 1⁄4
0.45 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.0
0.80 0.85 0.90 0.95 1.0
SwA/SwR
S SS
Swcor wAwA
wR
=⎛
⎝⎜⎞
⎠⎟
14
© Schlumberger
Formation Resistivity—Wireline
159
Rt
PurposeThe resistivity values of HALS laterolog deep resistivity (HLLD),HALS laterolog shallow resistivity (HLLS), and resistivity of theflushed zone (Rxo) measured by the High-Resolution AzimuthalLaterolog Sonde (HALS) are used with this chart to determine values for diameter of invasion (di) and true resistivity (Rt).
DescriptionThe conditions for which this chart is used are listed at the top. Thechart is entered with the ratios of HLLD/HLLS on the x-axis andHLLD/Rxo on the y-axis. The intersection point defines di on thedashed curves and the ratio of Rt/Rxo on the solid curves.
ExampleGiven: HLLD = 50 ohm-m, HLLS = 15 ohm-m, Rxo = 2.0 ohm-m,
and Rm = 0.2 ohm-m.
Find: Rt and diameter of invasion.
Answer: Enter the chart with the values of HLLD/HLLS = 50/15 =3.33 and HLLD/Rxo = 50/2 = 25.
The resulting point of intersection on the chart indicatesthat Rt/Rxo = 35 and di = 34 in.
Rt = 35 × 2.0 = 70 ohm-m.
High-Resolution Azimuthal Laterolog Sonde (HALS)Formation Resistivity and Diameter of Invasion—Open Hole
Rt-2
0.2
0.5
5
10
20
50
100
200
500
1,000
8 15 18 20 22 24 28 32 3640
4550
60
80
100
120
di (in.)
2
103
102
101
100
10–1
100 101 102
HLLD/Rxo
Thick Beds, 8-in. Hole, Rxo/Rm = 10
HLLD/HLLS
Rt/Rxo
© Schlumberger
Formation Resistivity—Wireline
High-Resolution Azimuthal Laterolog Sonde (HALS)Formation Resistivity and Diameter of Invasion—Open Hole Rt-3
160
PurposeThe resistivity values of high-resolution deep resistivity (HRLD), high-resolution shallow resistivity (HRLS), and Rxo measured by the HALSare used similarly to Chart Rt-2 to determine values for di and Rt.
DescriptionThe conditions for which this chart is used are listed at the top. Thechart is entered with the ratios of HRLD/HRLS on the x-axis andHRLD/Rxo on the y-axis. The intersection point defines di on thedashed curves and the ratio of Rt/Rxo on the solid curves.
Thick Beds, 8-in. Hole, Rxo/Rm = 10
HRLD/HRLS
HRLD/Rxo
di (in.)
1,000
8 15 18 20 22 24 28 32 3640
4550
60
80
100
120
0.2
0.5
2
103
102
101
100
10–1
500
200
100
50
20
10
5
100 101 102
Rt/Rxo
Rt
© Schlumberger
Formation Resistivity—LWD
161
Rt
PurposeThis chart is used to determine the correction applied to the log presentation of Rt and di determined from geoVISION675 ring (Rring)and deep (Rbd) and medium button (Rbm) resistivity values.
DescriptionEnter the chart with the ratios of Rring/Rbd on the x-axis andRring/Rbm on the y-axis. The intersection point defines di on the bluedashed curves, Rt/Rring on the red curves, and Rt/Rxo on the blackcurves. Charts Rt-11 through Rt-17 are similar to Chart Rt-10 for different tool sizes, configurations, and resistivity terms.
ExampleGiven: Rring = 30 ohm-m, Rxo/Rm = 50, Rbd = 15 ohm-m, and
Rbm = 6 ohm-m.
Find: Rt, di, and Rxo.
Answer: Enter the chart with values of Rring/Rbd = 30/15 = 2 onthe x-axis and Rring/Rbm = 30/6 = 5 on the y-axis to find di = 22.5 in., Rt/Rring = 3.1, and Rt/Rxo = 50. From theseratios, Rt = 3.1 × 30 = 93 ohm-m and Rxo = 93/50 = 1.86 ohm-m.
geoVISION675* ResistivityFormation Resistivity and Diameter of Invasion—Open Hole Rt-10
Ring, Deep, and Medium Button Resistivity (6.75-in. tool)
1 3
10
1
2
3
5
6
7
89
4
2
Rring/Rbd
Rring/Rbm
10070
50
30
20
15
10
7
5
3
2
24
22
20
1817
16
15
14
13
12
di
3.0
2.42.01.81.61.5
1.4
1.3
1.2
Rt/Rring
Rt/Rxo
Rxo/Rm = 50dh = 8.5 in.
*Mark of Schlumberger© Schlumberger
PurposeThis chart is used similarly to Chart Rt-10 to determine the correction applied to the log presentation of Rt and di determinedfrom geoVISION675 deep (Rbd), medium (Rbm), and shallow button (Rbs) resistivity values.
Formation Resistivity—LWD
geoVISION675* ResistivityFormation Resistivity and Diameter of Invasion—Open Hole Rt-11
162
Deep, Medium, and Shallow Button Resistivity (6.75-in. tool)
1
30
1
3
5
6
87
910
20
4
Rbd/Rbm
Rbd/Rbs
2
2 3 4 5 6
10070
50
30
20
15
10
7
5
3
18
17
16
151413
12
11
1.6
1.51.41.31.2
1.1
di
2
1
Rt/Rbd
Rt/Rxo
Rxo/Rm = 50dh = 8.5 in.
Rt
*Mark of Schlumberger© Schlumberger
Formation Resistivity—LWD
163
Rt
geoVISION675* ResistivityFormation Resistivity and Diameter of Invasion—Open Hole Rt-12
Bit, Ring, and Deep Button Resistivity (6.75-in. tool) with ROP to Bit Face = 4 ft
1
10
1
2
3
5
6
7
89
4
2
Rbit/Rring
Rbit/Rbd
3 4 5 6 7 8
24
10070
50
30
2015
10
7
5
3
2
1
50
40
34
28
22
20
18
16
4.03.02.5
2.0
1.8
1.6
1.4
di
Rt/Rbit
Rt/Rxo
Rxo/Rm = 50dh = 8.5 in.
PurposeThis chart is used similarly to Chart Rt-10 to determine the correc-tion applied to the log presentation of Rt and di determined fromgeoVISION675 Rring, bit (Rbit), and Rbd resistivity values.
*Mark of Schlumberger© Schlumberger
Formation Resistivity—LWD
geoVISION675* ResistivityFormation Resistivity and Diameter of Invasion—Open Hole Rt-13
164
Bit, Ring, and Deep Button Resistivity (6.75-in. tool) with ROP to Bit Face = 35 ft
1
1
3
5
6
87
910
20
4
Rbit/Rring
Rbit/Rbd
2
2 9876543 10 20
24
22
1.4
1.3
10070
50
30
20
15
10
7
5
3
2
1
70
5034
28
20
18
16
2.42.0
1.6
1.2
Rxo/Rm = 50dh = 8.5 in.
di
Rt/Rbit
Rt/Rxo
Rt
PurposeThis chart is used similarly to Chart Rt-10 to determine the correc-tion applied to the log presentation of Rt and di determined fromgeoVISION675 Rring, Rbit, and Rbd resistivity values.
*Mark of Schlumberger© Schlumberger
Formation Resistivity—LWD
165
Rt
geoVISION825* 81⁄4-in. Resistivity-at-the-Bit ToolFormation Resistivity and Diameter of Invasion—Open Hole Rt-14
Ring, Deep, and Medium Button Resistivity (81⁄4-in. tool)
1
10
1
2
3
5
6
7
8
9
4
2
Rring/Rbd
Rring/Rbm
1.2
17
10070
50
30
2015
10
7
5
3
2
1
30
26
242322
21
20
19
18
16
3.0
2.41.8
1.6
1.4
1.3
Rt/Rring
di
Rt/Rxo
Rxo/Rm = 50dh = 12.25 in.
PurposeThis chart is used similarly to Chart Rt-10 to determine the correc-tion applied to the log presentation of Rt and di determined fromgeoVISION825 Rring, Rbd, and Rbm resistivity values.
*Mark of Schlumberger© Schlumberger
Formation Resistivity—LWD
geoVISION825* 81⁄4-in. Resistivity-at-the-Bit ToolFormation Resistivity and Diameter of Invasion—Open Hole Rt-15
166
Deep, Medium, and Shallow Button Resistivity (81⁄4-in. tool)
1
1
3
5
6
87
910
20
4
Rbd/Rbm
Rbd/Rbs
2
32 4 5
10070
50
30
20
15
10
7
5
3
2
1
24
22
2019
18
17
16
14
2.42.0
1.61.41.3
1.2
1.1
di
Rt/Rbd
Rt/Rxo
Rxo/Rm = 50dh = 12.25 in.
Rt
PurposeThis chart is used similarly to Chart Rt-10 to determine the correc-tion applied to the log presentation of Rt and di determined fromgeoVISION825 Rbd, Rbm, and Rbs resistivity values.
*Mark of Schlumberger© Schlumberger
Formation Resistivity—LWD
167
Rt
geoVISION825* 81⁄4-in. Resistivity-at-the-Bit ToolFormation Resistivity and Diameter of Invasion—Open Hole Rt-16
10
1
2
3
5
6
7
8
9
4Rbit/Rbd
Bit, Ring, and Deep Button Resistivity (81⁄4-in. tool) with ROP to Bit Face = 4 ft
1
2
Rbit/Rring
3 4 5 6 7 8
10070
50
30
20
15
10
7
5
3
2
60
50
4035
30
28
26
24
22
20
5.0
3.02.4
2.01.8
1.6
1.5
1.4
1.3
1
di
Rt/Rbit
Rt/Rxo
Rxo/Rm = 50dh = 12.25 in.
PurposeThis chart is used similarly to Chart Rt-10 to determine the correc-tion applied to the log presentation of Rt and di determined fromgeoVISION825 Rring, Rbit, and Rbd resistivity values.
*Mark of Schlumberger© Schlumberger
Formation Resistivity—LWD
geoVISION825* 81⁄4-in. Resistivity-at-the-Bit ToolFormation Resistivity and Diameter of Invasion—Open Hole Rt-17
168
Bit, Ring, and Deep Button Resistivity (81⁄4-in. tool) with ROP to Bit Face = 35 ft
1
1
3
5
6
87
910
20
4
Rbit/Rring
Rbit/Rbd
2
1098765432 20
Rt/Rxo = 50dh = 12.25 in.
di
Rt/Rbit
Rt/Rxo
10070
50
30
20
15
10
7
5
3
2
1
70
5040
35
30
28
26
24
22
20
3.02.0
1.6
1.4
1.3
1.2
Rt
PurposeThis chart is used similarly to Chart Rt-10 to determine the correc-tion applied to the log presentation of Rt and di determined fromgeoVISION825 Rring, Rbit, and Rbd resistivity values.
*Mark of Schlumberger© Schlumberger
169
Rt
arcVISION* Array Resistivity Compensated Tool—400 kHzResistivity Anisotropy Versus Shale Volume—Open Hole Rt-31
PurposeThis chart illustrates the resistivity response, as affected by sand and shale layers, of the arcVISION tool in horizontal wellbores. The chart is used to determine the values of Rh and Rv. These corrections are already applied to the log presentation.
DescriptionThe chart is constructed for shale layers at 90° relative dip to theaxis of the arcVISION tool. That is, both the layers of shale and thetool are horizontal to the vertical. Other requirements for use of thischart are that the shale resistivity (Rsh) is 1 ohm-m and the sandresistivity is 5 or 20 ohm-m.
Select the appropriate chart for the attenuation (Rad) or phase-shift (Rps) resistivity and values of resistivity of the shale (Rsh) andsand (Rsand). Enter the chart with the volume of shale (Vsh) on the x-axis and the resistivity on the y-axis. At the intersection point ofthese two values move straight downward to the dashed blue curveto read the value of Rh. Move upward to the solid green curve to readthe value of Rv.
Chart Rt-32 is used to determine Rh and Rv values for the 2-MHzresistivity.
101Attenuation Resistivity
0 0.2 0.4 0.6 0.8 1.0100
101Phase-Shift Resistivity
Rps (ohm-m)
Vsh
Response Through Sand and Shale Layers at 90° Relative Dip for Rsh = 1 ohm-m and Rsand = 5 ohm-m
100
Rad (ohm-m)
0 0.2 0.4 0.6 0.8 1.0
Vsh
Attenuation Resistivity
Phase-Shift Resistivity
Response Through Sand and Shale Layers at 90° Relative Dip for Rsh = 1 ohm-m and Rsand = 20 ohm-m
101
100
0
Rps (ohm-m)
0.2 0.4 0.6 0.8 1.0
Vsh
102
101
100
0
Rad (ohm-m)
0.2 0.4 0.6 0.8 1.0
Vsh
Rh Rv
102
16 in. 22 in. 28 in. 34 in. 40 in.Resistivity spacing
Formation Resistivity—LWD
*Mark of Schlumberger© Schlumberger
Formation Resistivity—LWD
170
Rt
arcVISION* and ImPulse* Array Resistivity Compensated Tools—2 MHzResistivity Anisotropy Versus Shale Volume—Open Hole Rt-32
Phase-Shift Resistivity
Response Through Sand and Shale Layers at 90° Relative Dip for Rsh = 1 ohm-m and Rsand = 20 ohm-m
101
100
102
101
100
102Phase-Shift Resistivity
Response Through Sand and Shale Layers at 90° Relative Dip for Rsh = 1 ohm-m and Rsand = 5 ohm-m
101
100
102
101
100
102
0 0.2 0.4 0.6 0.8 1.0
Vsh
Rps(ohm-m)
0
Rps(ohm-m)
0.2 0.4 0.6 0.8 1.0
Vsh
Attenuation ResistivityAttenuation Resistivity
Rad(ohm-m)
0 0.2 0.4 0.6 0.8 1.0
Vsh
0
Rad(ohm-m)
0.2 0.4 0.6 0.8 1.0
Vsh
Rh Rv
16 in. 22 in. 28 in. 34 in. 40 in.Resistivity spacing
PurposeThis chart is used similarly to Chart Rt-31 for arcVISION andImPulse 2-MHz resistivity. These corrections are already applied to the log presentation.
*Mark of Schlumberger© Schlumberger
171
Rt
arcVISION* Array Resistivity Compensated Tool—400 kHzResistivity Anisotropy Versus Dip—Open Hole Rt-33
Phase-Shift Resistivity
Aniostropy Response for Rh = 1 ohm-m and (Rv/Rh) = 5
101
100
0 2010 40 60 80 90
Relative dip angle (°)
103
102
30 50 70 0 2010 40 60 80 90
Relative dip angle (°)
30 50 70
0 2010 40 60 80 9030 50 70
Relative dip angle (°)
0 2010 40 60 80 9030 50 70
Relative dip angle (°)
Attenuation Resistivity Attenuation Resistivity103
101
100
102
Phase-Shift Resistivity
Aniostropy Response for Rh = 1 ohm-m and (Rv/Rh) = 2
100
101
100
101
Rps(ohm-m)
Rad(ohm-m)
Rps(ohm-m)
Rad(ohm-m)
16 in. 22 in. 28 in. 34 in. 40 in.Resistivity spacing
Formation Resistivity—LWD
PurposeThis chart is used to determine arcVISION Rps and Rad for relativedip angles from 0 to 90°. These corrections are already applied to the log presentation.
DescriptionEnter the appropriate chart with the value of relative dip angle andmove to intersect the known resistivity spacing. Move horizontallyleft to read Rps or Rad for the conditions of the horizontal resistivity(Rh) = 1 ohm-m and the square root of the Rv/Rh ratio.
*Mark of Schlumberger© Schlumberger
Formation Resistivity—LWD
172
Rt
PurposeThis chart is used similarly to Chart Rt-33 for arcVISION andImPulse 2-MHz resistivity. These corrections are already applied to the log presentation.
arcVISION* and ImPulse* Array Resistivity Compensated Tools—2 MHzResistivity Anisotropy Versus Dip—Open Hole Rt-34
Phase-Shift Resistivity
Aniostropy Response for Rh = 1 ohm-m and (Rv/Rh) = 5
Phase-Shift Resistivity
Aniostropy Response for Rh = 1 ohm-m and (Rv/Rh) = 2
101
100
103
102
103
101
100
102
Rps(ohm-m)
Rad(ohm-m)
0 2010 40 60 80 90
Relative dip angle (°)
30 50 70
0 2010 40 60 80 9030 50 70
Relative dip angle (°)
100
101
100
101
Rps(ohm-m)
Rad(ohm-m)
0 2010 40 60 80 90
Relative dip angle (°)
30 50 70
0 2010 40 60 80 9030 50 70
Relative dip angle (°)
Attenuation Resistivity Attenuation Resistivity
16 in. 22 in. 28 in. 34 in. 40 in.Resistivity spacing
*Mark of Schlumberger© Schlumberger
173
Rt
Formation Resistivity—LWD
arcVISION* Array Resistivity Compensated Tool—400 kHzResistivity Anisotropy Versus Square Root of Rv/Rh—Open Hole Rt-35
PurposeThis chart and Chart Rt-36 reflect the effect of anisotropy on thearcVISION resistivity response. These corrections are already applied to the log presentation. As the square root of the Rv/Rh
ratio increases, the effect on the resistivity significantly increases.
DescriptionEnter the appropriate chart with the value of the phase-shift orattenuation resistivity on the y-axis. Move horizontally to intersectthe resistivity spacing curve. At the intersection point read the valueof the square root of the Rv/Rh ratio on the x-axis.
Phase-Shift Resistivity
Aniostropy Response at 85° dip for Rh = 1 ohm-m
101
100
1.0
Rps(ohm-m)
2.01.5 3.0 4.0 5.0
(Rv/Rh)
103
102
101
100
Rad(ohm-m)
103
102
2.5 3.5 4.5 1.0 2.01.5 3.0 4.0 5.02.5 3.5 4.5
1.0 2.01.5 3.0 4.0 5.02.5 3.5 4.51.0 2.01.5 3.0 4.0 5.0
(Rv/Rh)
2.5 3.5 4.5
Attenuation Resistivity Attenuation Resistivity
Phase-Shift Resistivity
Aniostropy Response at 65° dip for Rh = 1 ohm-m
100
Rps(ohm-m)
101
101
100
Rad(ohm-m)
16 in. 22 in. 28 in. 34 in. 40 in.Resistivity spacing
(Rv/Rh)
(Rv/Rh)
*Mark of Schlumberger© Schlumberger
Formation Resistivity—LWD
174
Rt
PurposeThis chart is used similarly to Chart Rt-35 for arcVISION andImPulse for 2-MHz resistivity. These corrections are already applied to the log presentation.
arcVISION* and ImPulse* Array Resistivity Compensated Tools—2 MHzResistivity Anisotropy Versus Square Root of Rv/Rh—Open Hole Rt-36
Phase-Shift Resistivity
Aniostropy Response at 85° dip for Rh = 1 ohm-m
Phase-Shift Resistivity
Aniostropy Response at 65° dip for Rh = 1 ohm-m
1.0 2.01.5 3.0 4.0 5.02.5 3.5 4.5 1.0 2.01.5 3.0 4.0 5.0
(Rv/Rh)
2.5 3.5 4.5
1.0 2.01.5 3.0 4.0 5.0
(Rv/Rh)
2.5 3.5 4.51.0 2.01.5 3.0 4.0 5.0
(Rv/Rh)
2.5 3.5 4.5
Attenuation Resistivity Attenuation Resistivity
101
100
Rps(ohm-m)
103
102
101
100
Rad(ohm-m)
103
102
100
Rps(ohm-m)
101
101
100
Rad(ohm-m)
16 in. 22 in. 28 in. 34 in. 40 in.Resistivity spacing
(Rv/Rh)
*Mark of Schlumberger© Schlumberger
175
Rt
Formation Resistivity—LWD
arcVISION675* Array Resistivity Compensated Tool—400 kHzConductive Invasion—Open Hole Rt-37
PurposeThis log-log chart is used to determine the correction applied to the log presentation of the 40-in. arcVISION675 resistivity measure-ments, diameter of invasion (di), and resistivity of the flushed zone(Rxo). These data are used to evaluate a formation for hydrocarbons.
DescriptionEnter the chart with the ratio of the 16-in. Rps /40-in. Rad on the y-axisand 28-in. Rps /40-in. Rad on the x-axis. The intersection point definesthe following:
di
Rxo
correction factor for 40-in. attenuation resistivity.
Chart Rt-38 is used for 2-MHz resistivity values. The correspondingcharts for resistive invasion are Charts Rt-39 and Rt-40.
ExampleGiven: 16-in. Rps/40-in. Rad = 0.2 and 28-in. Rps/40-in. Rad = 0.4.
Find: Rxo, di, and correction factor for 40-in. Rad.
Answer: At the intersection point of 0.2 on the y-axis and 0.4 onthe x-axis, di = 31.9 in., Rxo = 1.1 ohm-m, and correctionfactor = 0.955.
The value of the 40-in. Rad is reduced by the correctionfactor: 40-in. Rad × 0.955.
28-in. Rps/40-in. Rad
16-in. Rps/40-in. Rad
0.010.01
0.1
0.1
1.0
1.0
Rxo and di for Rt ~ 10 ohm-m
16
20
2428
32
36404448
52
56
60
64
0.15
0.20.3
0.5
0.71
1.5
2
3
5
7
0.95
0.9
0.80.85
0.750.7
0.650.6
0.55
40-in. Rad/Rt = 1
di (in.)
Rxo = 0.1 ohm−m
*Mark of Schlumberger© Schlumberger
Formation Resistivity—LWD
176
Rt
arcVISION675* and ImPulse* Array Resistivity Compensated Tools—2 MHzConductive Invasion—Open Hole Rt-38
28-in. Rps /40-in. Rad
16-in. Rps /40-in. Rad
0.010.01
0.1 1.0
1.0Rxo and di for Rt ~ 10 ohm-m
0.3
0.5
0.15
7
0.7
1
1.5
2
3
5
16
20
24283236
40
44
48 52
di (in.)
56
0.2
40-in. Rad/Rt = 1
0.9
0.8
0.7
0.3
0.60.5
0.2
0.1
0.4
Rxo = 0.1 ohm-m
PurposeThis chart is used similarly to Chart Rt-37 for arcVISION675 andImPulse 2-MHz resistivity. The corrections are already applied to the log presentation.
*Mark of Schlumberger© Schlumberger
177
Rt
Formation Resistivity—LWD
arcVISION* Array Resistivity Compensated Tool—400 kHzResistive Invasion—Open Hole Rt-39
30
35
40
45
50
55
60
65
70
75
80
90
100
125
200
150
100
70
50
30
20
15
di (in.)
Rxo = 300 ohm-m
28-in. Rps /40-in. Rad
16-in. Rps /40-in. Rad
11
10
10 Rxo and di for Rt ~ 10 ohm-m
Rt /40-in. Rad = 1
0.95
0.9
0.85
0.8
0.75
0.7
0.65
0.6
0.55
PurposeThis chart is used similarly to Chart Rt-37 to determine the correc-tion applied to the arcVISION log presentation of di, Rxo, and 40-in.Rad for resistive invasion.
*Mark of Schlumberger© Schlumberger
Formation Resistivity—LWD
178
Rt
arcVISION* and ImPulse* Array Resistivity Compensated Tools—2 MHzResistive Invasion—Open Hole Rt-40
28-in. Rps /40-in. Rad
16-in. Rps/40-in. Rad
Rxo and di for Rt ~ 10 ohm-m
1 1.05 1.1 1.15 1.2 1.25 1.3 1.35 1.41.0
1.2
1.4
1.6
2.0
2.2
2.4
1.840
55
60
di (in.)
30
200
150
100
70
50
30
20
15
35
45
0.95
0.9
0.85
0.8
0.75
0.7
0.65
0.55
0.6
Rt/40-in. Rad = 1
50
65
Rxo = 300 ohm-m
PurposeThis chart is used similarly to Chart Rt-39 to determine the correc-tion applied to the arcVISION and ImPulse log presentation for 2-MHz resistivity.
*Mark of Schlumberger© Schlumberger
179
Rt
arcVISION* Array Resistivity Compensated Tool—400 kHz in Horizontal WellBed Proximity Effect—Open Hole
Formation Resistivity—LWD
PurposeCharts Rt-41 and Rt-42 are used to calculate the correction appliedto the log presentation of Rt from the arcVISION tool at theapproach to a bed boundary. The value of Rt is used to calculatewater saturation.
DescriptionThere are two sets of charts for differing conditions:
shoulder bed resistivity (Rshoulder) = 10 ohm-m and Rt = 1 ohm-m Rshoulder = 10 ohm-m and Rt =100 ohm-m.
Example
Given: Rshoulder = 10 ohm-m, Rt = 1 ohm-m, and 16-in. Rps = 1.5 ohm-m.
Find: Bed proximity effect.
Answer: The top set of charts is appropriate for these resistivityvalues. The ratio Rps/Rt = 1.5/1 = 1.5.
Enter the y-axis of the left-hand chart at 1.5 and movehorizontally to intersect the 16-in. curve. The corre-sponding value on the x-axis is 1 ft, which is the distanceof the surrounding bed from the tool. At 2 ft from thebed boundary, the value of 16-in. Rps = 1 ohm-m.
continued on next page
Formation Resistivity–Drill PipeFormation Resistivity—LWD
180
Rt
arcVISION* Array Resistivity Compensated Tool—400 kHz in Horizontal WellBed Proximity Effect—Open Hole Rt-41
0 1 2 3 4 5 6 7 8 9 100
1
2
3
Distance to bed boundary (ft)
0 1 2 3 4 5 6 7 8 9 10Distance to bed boundary (ft)
Rps/Rt
Bed Proximity Effect for Horizontal Well: Rshoulder = 10 ohm-m and Rt = 1 ohm-m
0 1 2 3 4 5 6 7 8 9 100
1
2
3
Distance to bed boundary (ft)
Rad/Rt
0 1 2 3 4 5 6 7 8 9 10Distance to bed boundary (ft)
0
1
2
3
Rps/Rt
0
1
2
3
Rad/Rt
Bed Proximity Effect for Horizontal Well: Rshoulder = 10 ohm-m and Rt = 100 ohm-m
16 in. 22 in. 28 in. 34 in. 40 in.Resistivity spacing
*Mark of Schlumberger© Schlumberger
181
Rt
Formation Resistivity—LWD
arcVISION* and ImPulse* Array Resistivity Compensated Tools—2 MHz in Horizontal WellBed Proximity Effect—Open Hole
Bed Proximity Effect for Horizontal Well: Rshoulder = 10 ohm-m, Rt = 1 ohm-m
Bed Proximity Effect for Horizontal Well: Rshoulder = 10 ohm-m, Rt = 100 ohm-m
0
1
2
3
Rps/Rt
0 1 2 3 4 5 6 7 8 9 10
Distance to bed boundary (ft)
0
1
2
3
Rps/Rt
0 1 2 3 4 5 6 7 8 9 10Distance to bed boundary (ft)
0 1 2 3 4 5 6 7 8 9 10Distance to bed boundary (ft)
0
1
2
3
Rad/Rt
0 1 2 3 4 5 6 7 8 9 10
Distance to bed boundary (ft)
0
1
2
3
Rad/Rt
16 in. 22 in. 28 in. 34 in. 40 in.Resistivity spacing
Rt-42
PurposeThis chart is used similarly to Chart Rt-41 for arcVISION andImPulse 2-MHz resistivity. The correction is already applied to the log presentation.
*Mark of Schlumberger© Schlumberger
General
182
GeneralLithology—Wireline
Density and NGS* Natural Gamma Ray Spectrometry ToolMineral Identification—Open Hole
PurposeThis chart is a method for identifying the type of clay in the wellbore.The values of the photoelectric factor (Pe) from the Litho-Density*log and the concentration of potassium (K) from the NGS NaturalGamma Ray Spectrometry tool are entered on the chart.
DescriptionEnter the upper chart with the values of Pe and K to determine thepoint of intersection. On the lower chart, plotting Pe and the ratio of thorium and potassium (Th/K) provides a similar mineral evalua-tion. The intersection points are not unique but are in general areasdefined by a range of values.
ExampleGiven: Environmentally corrected thorium concentration
(ThNGScorr) = 10.6 ppm, environmentally correctedpotassium concentration (KNGScorr) = 3.9%, and Pe = 3.2.
Find: Mineral concentration of the logged clay.
Answer: The intersection points from plotting values of Pe and Kon the upper chart and Pe and Th/K ratio = 10.6/3.9 = 2.7on the lower chart suggest that the clay mineral is illite.
Lith
183
Lith
Lithology—Wireline
Density and NGS* Natural Gamma Ray Spectrometry ToolMineral Identification—Open Hole Lith-1
(former CP-18)
Potassium concentration, K (%)
Thorium/potassium ratio, Th/K
Photoelectricfactor, Pe
Photoelectricfactor, Pe
Glauconite
Glauconite
Chlorite
Chlorite
Biotite
Biotite
Illite
Illite
Muscovite
Muscovite
Montmorillonite
Montmorillonite
Kaolinite
Kaolinite
Mixed layer
0 2 4 6 8 10
0.1 0.2 0.3 0.6 1 2 3 6 10 20 30 60 100
10
8
6
4
2
0
10
8
6
4
2
0
*Mark of Schlumberger© Schlumberger
Lithology—Wireline
NGS* Natural Gamma Ray Spectrometry ToolMineral Identification—Open Hole Lith-2
(former CP-19)
184
PurposeThis chart is used to determine the type of minerals in a shale formation from concentrations measured by the NGS NaturalGamma Ray Spectrometry tool.
DescriptionEntering the chart with the values of thorium and potassium locatesthe intersection point used to determine the type of radioactive min-erals that compose the majority of the clay in the formation.
A sandstone reservoir with varying amounts of shaliness andillite as the principal clay mineral usually plots in the illite segmentof the chart with Th/K between 2.0 and 3.5. Less shaly parts of thereservoir plot closer to the origin, and shaly parts plot closer to the70% illite area.
0 1 2 3 4 5
Potassium (%)
25
20
15
10
5
0
Thorium(ppm)
Mixed-layer clay
IlliteMicas
Glauconite
Potassium evaporites, ~30% feldspar
~30% glauconite
~70% illite
100% illite point
~40%mica
Mon
tmor
illonit
e
Chlorite
Kaolinite
Possible 100% kaolinite,montmorillonite,illite “clay line”
Th/K
= 2
5
Th/K
= 12
Th/K = 3.5
Th/K = 2.0
Th/K = 0.6
Th/K = 0.3Feldspar
Heav
y th
oriu
m-b
earin
g m
iner
als
Lith
*Mark of Schlumberger© Schlumberger
Lith
PurposeThis chart is used to determine the lithology and porosity of a forma-tion. The porosity is used for the water saturation determination andthe lithology helps to determine the makeup of the logged formation.
DescriptionNote that this chart is designed for fresh water (fluid density [ρf]= 1.0 g/cm3) in the borehole. Chart Lith-4 is used for saltwater(ρf = 1.1 g/cm3) formations.
Values of photoelectric factor (Pe) and bulk density (ρb) from thePlatform Express Three-Detector Lithology Density (TLD) tool areentered into the chart. At the point of intersection, porosity andlithology values can be determined.
ExampleGiven: Freshwater drilling mud, Pe = 3.0, and bulk density =
2.73 g/cm3.
Freshwater drilling mud, Pe = 1.6, and bulk density =2.24 g/cm3.
Find: Porosity and lithology.
Answer: For the first set of conditions, the formation is adolomite with 8% porosity.
The second set is for a quartz sandstone formation with 30% porosity.
Lithology—Wireline
Platform Express* Three-Detector Lithology Density ToolPorosity and Lithology—Open Hole
continued on next page
185
Lithology—Wireline
Platform Express* Three-Detector Lithology Density ToolPorosity and Lithology—Open Hole Lith-3
(former CP-16)
186
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0 0 1 2 3 4 5 6
Photoelectric factor, Pe
Bulk density, ρb(g/cm3)
4030
2010
0
4030
2010
0
0
40
30
2010
0
0
Quar
tz s
ands
tone
Dolo
mite
Calc
ite (l
imes
tone
)Sa
lt
Anhy
drite
Fresh Water (ρf = 1.0 g/cm3), Liquid-Filled Borehole
Lith
*Mark of Schlumberger© Schlumberger
187
Lith
Lithology—Wireline
Platform Express* Three-Detector Lithology Density ToolPorosity and Lithology—Open Hole Lith-4
(former CP-17)
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0 0 1 2 3 4 5 6
Photoelectric factor, Pe
Bulk density, ρb(g/cm3)
4030
2010
0
4030
2010
0
0
Quar
tz s
ands
tone
Dolo
mite
Anhy
drite
40
30
2010
0
Calc
ite (l
imes
tone
)
0Salt
Salt Water (ρf = 1.1 g/cm3), Liquid-Filled Borehole
This chart is used similarly to Chart Lith-3 for lithology and poros-ity determination with values of photoelectric factor (Pe) and
bulk density (ρb) from the Platform Express TLD tool in saltwaterborehole fluid.
*Mark of Schlumberger© Schlumberger
GeneralLithology—Wireline, Drillpipe
Density ToolApparent Matrix Volumetric Photoelectric Factor—Open Hole Lith-5
(former CP-20)
PurposeThis chart is used to determine the apparent matrix volumetric photoelectric factor (Umaa) for the Chart Lith-6 percent lithologydetermination.
DescriptionThis chart is entered with the values of bulk density (ρb) and Pe froma density log. The value of the apparent total porosity (φta) must alsobe known. The appropriate solid lines on the right-hand side of thechart that indicate a freshwater borehole fluid or dotted lines thatrepresent saltwater borehole fluid are used depending on the salinityof the borehole fluid. Uf is the fluid photoelectric factor.
ExampleGiven: Pe = 4.0, ρb = 2.5 g/cm3, φta = 25%, and freshwater
borehole fluid.
Find: Apparent matrix volumetric photoelectric factor (Umaa).
Answer: Enter the chart with the Pe value (4.0) on the left-handx-axis, and move upward to intersect the curve for ρb = 2.5 g/cm3.
From that intersection point, move horizontally right tointersect the φta value of 25%, using the blue freshwatercurve.
Move vertically downward to determine the Umaa valueon the right-hand x-axis scale: Umaa = 13.
Lithology—Wireline, LWD
188
6 5 4 3 2 1 4 6 8 10 12 14
3.0
2.5
2.0
0
10
20
30
40
Photoelectric factor, Pe
Bulk density, ρb
(g/cm3)
Apparent total porosity, φta (%)
Apparent matrixvolumetric photoelectric factor, Umaa
Fresh water (0 ppm), ρf = 1.0 g/cm3, Uf = 0.398Salt water (200,000 ppm), ρf = 1.11 g/cm3, Uf = 1.36
Lith
© Schlumberger
continued on next page
189
Lith
GeneralGeneralGeneralLithology—Wireline, LWD
PurposeThis chart is used to identify the rock mineralogy through comparisonof the apparent matrix grain density (ρmaa) and apparent matrix volu-metric photoelectric factor (Umaa).
DescriptionThe values of ρmaa and Umaa are entered on the y- and x-axis, respec-tively. The rock mineralogy is identified by the proximity of the pointof intersection of the two values to the labeled points on the plot.The effect of gas, salt, etc., is to shift data points in the directionsshown by the arrows.
ExampleGiven: ρmaa = 2.74 g/cm3 (from Chart Lith-9 or Lith-10) and
Umaa = 13 (from Chart Lith-5).
Find: Matrix composition of the formation.
Answer: Enter the chart with ρmaa = 2.74 g/cm3 on the y-axis andUmaa = 13 on the x-axis. The intersection point indicatesa matrix mixture of 20% dolomite and 80% calcite.
Density ToolLithology Identification—Open Hole
General
190
Lith
GeneralLithology—Wireline, LWD
Apparent matrix volumetric photoelectric factor, Umaa
Apparent matrixgrain density,ρmaa (g/cm3)
2 4 6 8 10 12 14 16
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
Salt
K-feldspar
Quartz
Dolomite
Kaolinite
Illite
Anhydrite
Heavy minerals
Barite
Calcite
Gas
dire
ctio
n
% calcite
% dolomite
% quartz
2060
8040
60
40
20
80
60
40
20
80
Density ToolLithology Identification—Open Hole Lith-6
(former CP-21)
© Schlumberger
continued on next page
191
Lith
PurposeThis chart is used to help identify mineral mixtures from sonic, density, and neutron logs.
DescriptionBecause M and N slope values are practically independent of porosityexcept in gas zones, the porosity values they indicate can be corre-lated with the mineralogy. (See Appendix E for the formulas to calcu-late M and N from sonic, density, and neutron logs.)
Enter the chart with M on the y-axis and N on the x-axis. Theintersection point indicates the makeup of the formation. Points forbinary mixtures plot along a line connecting the two mineral points.Ternary mixtures plot within the triangle defined by the three con-stituent minerals. The effect of gas, shaliness, secondary porosity,etc., is to shift data points in the directions shown by the arrows.
The lines on the chart are divided into numbered groups by poros-ity range as follows:
1. φ = 0 (tight formation)2. φ = 0 to 12 p.u.3. φ = 12 to 27 p.u.4. φ = 27 to 40 p.u.
ExampleGiven: M = 0.79 and N = 0.51.
Find: Mineral composition of the formation.
Answer: The intersection of the M and N values indicates dolomitein group 2, which has a porosity between 0 to 12 p.u.
Lithology—Wireline, LWD
Environmentally Corrected Neutron CurvesM–N Plot for Mineral Identification—Open Hole
Lithology—Wireline, LWD
Environmentally Corrected Neutron CurvesM–N Plot for Mineral Identification—Open Hole Lith-7
(former CP-8)
192
1.1
1.0
0.9
0.8
0.7
0.6
0.5
Approximate shale region
Anhydrite
Dolomite
Gypsum
Calcite (limestone)
vma = 5943 m/s = 19,500 ft/s
vma = 5486 m/s = 18,000 ft/s
Sulfur
Quartz sandstone
324 1
1 2 34
Secondaryporosity
Gas or
salt
N
M
0.3 0.4 0.5 0.6 0.7 0.8
Freshwater mudρf = 1.0 Mg/m3, t f = 620 µs/mρf = 1.0 g/cm3, t f = 189 µs/ft
Saltwater mudρf = 1.1 Mg/m3, t f = 607 µs/mρf = 1.1 g/cm3, t f = 185 µs/ft
Lith
© Schlumberger
continued on next page
193
Lith
GeneralGeneralGeneralLithology—Wireline
PurposeThis chart is used to help identify mineral mixtures from APSAccelerator Porosity Sonde neutron logs.
DescriptionBecause M and N values are practically independent of porosityexcept in gas zones, the porosity values they indicate can be corre-lated with the mineralogy. (See Appendix E for the formulas to cal-culate M and N from sonic, density, and neutron logs.)
Enter the chart with M on the y-axis and N on the x-axis. Theintersection point indicates the makeup of the formation. Points forbinary mixtures plot along a line connecting the two mineral points.Ternary mixtures plot within the triangle defined by the three con-stituent minerals. The effect of gas, shaliness, secondary porosity,etc., is to shift data points in the directions shown by the arrows.
The lines on the chart are divided into numbered groups by poros-ity range as follows:
1. φ = 0 (tight formation)2. φ = 0 to 12 p.u.3. φ = 12 to 27 p.u.4. φ = 27 to 40 p.u.
Because the dolomite spread is negligible, a single dolomite pointis plotted for each mud.
ExampleGiven: M = 0.80 and N = 0.55.
Find: Mineral composition of the formation.
Answer: Dolomite.
Environmentally Corrected APS* CurvesM–N Plot for Mineral Identification—Open Hole
General
194
1.1
1.0
0.9
0.8
0.7
0.6
0.5
Approximate shale region
Anhydrite
Dolomite
Gypsum
Calcite (limestone)
vma = 5943 m/s = 19,500 ft/s
vma = 5486 m/s = 18,000 ft/s
Sulfur
Quartz sandstone
12 3,4
Secondaryporosity
Gas or
salt
N
M
0.3 0.4 0.5 0.6 0.7 0.8
Freshwater mudρf = 1.0 Mg/m3, t f = 620 µs/mρf = 1.0 g/cm3, t f = 189 µs/ft
Saltwater mudρf = 1.1 Mg/m3, t f = 607 µs/mρf = 1.1 g/cm3, t f = 185 µs/ft
Lith
GeneralLithology—Wireline
Environmentally Corrected APS* CurvesM–N Plot for Mineral Identification—Open Hole Lith-8
(former CP-8a)
*Mark of Schlumberger© Schlumberger
continued on next page
195
Lith
PurposeCharts Lith-9 (customary units) and Lith-10 (metric units) providevalues of the apparent matrix internal transit time (tmaa) and appar-ent matrix grain density (ρmaa) for the matrix identification (MID)Charts Lith-11 and Lith-12. With these parameters the identificationof rock mineralogy or lithology through a comparison of neutron,density, and sonic measurements is possible.
DescriptionDetermining the values of tmaa and ρmaa to use in the MID ChartsLith-11 and Lith-12 requires three steps.
First, apparent crossplot porosity is determined using the appro-priate neutron-density and neutron-sonic crossplot charts in the“Porosity” section of this book. For data that plot above the sand-stone curve on the charts, the apparent crossplot porosity is definedby a vertical projection to the sandstone curve.
Second, enter Chart Lith-9 or Lith-10 with the interval transit time (t) to intersect the previously determined apparent crossplotporosity. This point defines tmaa.
Third, enter Chart Lith-9 or Lith-10 with the bulk density (ρb) to again intersect the apparent crossplot porosity and define ρmaa.
The values determined from Charts Lith-9 and Lith-10 for tmaa andρmaa are cross plotted on the appropriate MID plot (Charts Lith-11and Lith-12) to identify the rock mineralogy by its proximity to thelabeled points on the plot.
ExampleGiven: Apparent crossplot porosity from density-neutron = 20%,
ρb = 2.4 g /cm3, apparent crossplot porosity from neutron-sonic = 30%, and t = 82 µs/ft.
Find: ρmaa and tmaa.
Answer: ρmaa = 2.75 g/cm3 and tmaa = 46 µs/ft.
Lithology—Wireline, LWD
Bulk Density or Interval Transit Time and Apparent Total PorosityApparent Matrix Parameters—Open Hole
Lithology—Wireline, LWD
Bulk Density or Interval Transit Time and Apparent Total PorosityApparent Matrix Parameters—Open Hole Lith-9
(customary, former CP-14)
196
3.0 2.9 2.8 2.7 2.6 2.5 2.4 2.3 2.2 2.1 2.0
130 120 110 100 90 80 70 60 50 40 303.0
2.9
2.8
2.7
2.6
2.5
2.4
2.3
2.2
2.1
2.0
130
120
110
100
90
80
70
60
50
40
30
Fluid Density = 1.0 g/cm3
Apparent matrix density, ρmaa (g/cm3)
Bulk density,ρb (g/cm3)
Intervaltransittime,
t (µs/ft)
Apparent matrix transit time, tmaa (µs/ft)
40
30
20
10
10
20
30
40
Apparentcrossplotporosity
Density-n
eutron
Neutron-so
nic
Lith
© Schlumberger
197
Lith
PurposeCharts Lith-9 (customary units) and Lith-10 (metric units) providevalues of the apparent matrix internal transit time (tmaa) and appar-ent matrix grain density (ρmaa) for the matrix identification (MID)Charts Lith-11 and Lith-12. With these parameters the identificationof rock mineralogy or lithology through a comparison of neutron,density, and sonic measurements is possible.
GeneralGeneralGeneral
3.0 2.9 2.8 2.7 2.6 2.5 2.4 2.3 2.2 2.1 2.0
350 325 300 275 250 225 200 175 150 125 100 3.0
2.9
2.8
2.7
2.6
2.5
2.4
2.3
2.2
2.1
2.0
350
325
300
275
250
225
200
175
150
125
100
Fluid Density = 1.0 g/cm3
Apparent matrix density, ρmaa (g/cm3)
Bulk density,ρb (g/cm3)
Intervaltransittime,
t (µs/m)
Apparent matrix transit time, tmaa (µs/m)
40
30
20
10
10
20
30
40
Apparentcrossplotporosity
Density-n
eutron
Neutron-so
nic
Lithology—Wireline, LWD
Bulk Density or Interval Transit Time and Apparent Total PorosityApparent Matrix Parameters—Open Hole Lith-10
(metric, former CP-14m)
© Schlumberger
General
198
PurposeCharts Lith-11 and Lith-12 are used to establish the type of mineralpredominant in the formation.
DescriptionEnter the appropriate (customary or metric units) chart with the values established from Charts Lith-9 or Lith-10 to identify thepredominant mineral in the formation. Salt points are defined fortwo tools, the sidewall neutron porosity (SNP) and the CNL*Compensated Neutron Log. The presence of secondary porosity in the form of vugs or fractures displaces the data points parallel to the apparent matrix internal transit time (tmaa) axis. The presence of gas displaces points to the right on the chart. Plotting some shalepoints to establish the shale trend lines helps in the identificationof shaliness. For fluid density (ρf) other than 1.0 g/cm3 use the tableto determine the multiplier to correct the apparent total densityporosity before entering Chart Lith-11 or Lith-12.
ExampleGiven: ρmaa = 2.75 g/cm3, tmaa = 56 µs/ft (from Chart Lith-9),
and ρf = 1.0 g/cm3.
Find: The predominant mineral.
Answer: The formation consists of both dolomite and calcite,which indicates a dolomitized limestone. The formationused in this example is from northwest Florida in the Jay field. The vugs (secondary porosity) created by thedolomitization process displace the data point parallel to the dolomite and calcite points.
Lith
GeneralLithology—Wireline, LWD
Density ToolMatrix Identification (MID)—Open Hole
ρf Multiplier
1.00 1.001.05 0.981.10 0.951.15 0.93
199
Lith
GeneralGeneralGeneral
30 40 50 60 70
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
tmaa (µs/ft)
ρmaa(g/cm3)
Calcite
Dolomite
Anhydrite
Quartz
Gas direction
Salt (CNL* log)
Salt (SNP)
Lithology—Wireline, LWD
Density ToolMatrix Identification (MID)—Open Hole Lith-11
(customary, former CP-15)
*Mark of Schlumberger© Schlumberger
Lithology—Wireline, LWD
Density ToolMatrix Identification (MID)—Open Hole Lith-12
(metric, former CP-15m)
200
PurposeChart Lith-12 is used similarly to Chart Lith-11 to establish the mineraltype of the formation.
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
3.1
100 120 140 160 180 200 220 240
tmaa (µs/m)
ρmaa(g/cm3)
Calcite
Dolomite
Anhydrite
Quartz
Gas direction
Salt (SNP)
Salt (CNL* log)
Lith
*Mark of Schlumberger© Schlumberger
continued on next page
201
Por
GeneralPorosity—Wireline, LWD
Sonic ToolPorosity Evaluation—Open Hole
PurposeThis chart is used to convert sonic log slowness time (∆t) values into those for porosity (φ).
DescriptionThere are two sets of curves on the chart. The blue set for matrixvelocity (vma) employs a weighted-average transform. The red set is based on the empirical observation of lithology (see Reference20). For both, the saturating fluid is assumed to be water with a velocity (vf) of 5,300 ft/s (1,615 m/s).
Enter the chart with the slowness time from the sonic log on the x-axis. Move vertically to intersect the appropriate matrix velocityor lithology curve and read the porosity value on the y-axis. For rockmixtures such as limy sandstones or cherty dolomites, intermediatematrix lines may be interpolated.
To use the weighted-average transform for an unconsolidated sand,a lack-of-compaction correction (Bcp) must be made. Enter the chartwith the slowness time and intersect the appropriate compactioncorrection line to read the porosity on the y-axis. If the compactioncorrection is not known, it can be determined by working backwardfrom a nearby clean water sand for which the porosity is known.
Example: Consolidated FormationGiven: ∆t = 76 µs/ft in a consolidated formation with
vma = 18,000 ft/s.
Find: Porosity and the formation lithology (sandstone,dolomite, or limestone).
Answer: 15% porosity and consolidated sandstone.
Example: Unconsolidated FormationGiven: Unconsolidated formation with ∆t = 100 µs/ft in
a nearby water sand with a porosity of 28%.
Find: Porosity of the formation for ∆t = 110 µs/ft.
Answer: Enter the chart with 100 µs/ft on the x-axis and movevertically upward to intersect 28-p.u. porosity. Thisintersection point indicates the correction factor curveof 1.2. Use the 1.2 correction value to find the porosity forthe other slowness time. The porosity of an unconsoli-dated formation with ∆t = 110 µs/ft is 34 p.u.
Lithology vma (ft/s) ∆tma (µs/ft) vma (m/s) ∆tma (µs/m)
Sandstone 18,000–19,500 55.5–51.3 5,486–5,944 182–168Limestone 21,000–23,000 47.6–43.5 6,400–7,010 156–143Dolomite 23,000–26,000 43.5–38.5 7,010–7,925 143–126
Porosity—Wireline, LWD
Sonic ToolPorosity Evaluation—Open Hole Por-1
(customary, former Por-3)
30 40 50 60 70 80 90 100 110 120 130
Interval transit time, ∆t (µs/ft)
vf = 5,300 ft/s50
40
30
20
10
0
50
40
30
20
10
0
Porosity, φ (p.u.)
Porosity, φ (p.u.)
Time averageField observation
1.1
1.2
1.3
1.4
1.5
1.6
Dolomite
26,00
021
,000
18,00
0
vma(ft/s)
Bcp
23,00
019
,500
Calcite(lim
estone)
Quartzsandstone
202
Por
© Schlumberger
Por
203
Porosity—Wireline, LWD
Sonic ToolPorosity Evaluation—Open Hole Por-2
(metric, former Por-3m)
100 150 200 250 300 350 400
Interval transit time, ∆t (µs/m)
vf = 1,615 m/s50
40
30
20
10
0
50
40
30
20
10
0
Porosity, φ (p.u.)
Porosity, φ (p.u.)
1.1
1.2
1.3
1.4
1.5
1.6
Dolomite
8,000
6,400
5,500
5,950
vma(m/s)
Bcp
Time averageField observation
7,000
Calcite
Quartzsandstone
Dolomite
Calci
teQua
rtzsa
ndsto
ne
Cemen
ted qu
artz
sand
stone
PurposeThis chart is used similarly to Chart Por-1 with metric units.
© Schlumberger
204
Por
Por-3(former Por-5)
Density ToolPorosity Determination—Open Hole
PurposeThis chart is used to convert grain density (g/cm3) to density porosity.
DescriptionValues of log-derived bulk density (ρb) corrected for borehole size,matrix density of the formation (ρma), and fluid density (ρf) are usedto determine the density porosity (φD) of the logged formation. Theρf is the density of the fluid saturating the rock immediately sur-rounding the borehole—usually mud filtrate.
Enter the borehole-corrected value of ρb on the x-axis and movevertically to intersect the appropriate matrix density curve. From theintersection point move horizontally to the fluid density line. Followthe porosity trend line to the porosity scale to read the formation
porosity as determined by the density tool. This porosity in combina-tion with CNL* Compensated Neutron Log, sonic, or both values ofporosity can help determine the rock type of the formation.
ExampleGiven: ρb = 2.31 g/cm3 (log reading corrected for borehole
effect), ρma = 2.71 g/cm3 (calcite mineral), and ρf = 1.1 g/cm3 (salt mud).
Find: Density porosity.
Answer: φD = 25 p.u.
2.8 2.6 2.4 2.2 2.02.31
1.0 0.9 0.8
1.1
1.2
Porosity, φ (p.u.)
Bulk density, ρb (g/cm3)
ρ ma= 2.8
7 (dolomite)
ρ ma= 2.7
1 (calci
te)
ρ ma= 2.6
5 (quar
tzsa
ndsto
ne)
ρ ma= 2.8
3ρ ma
= 2.68
ρma – ρb
ρma – ρfφ =
ρf (g/cm3)
40
30
20
10
0
Porosity—Wireline, LWD
*Mark of Schlumberger© Schlumberger
continued on next page
205
Por
PurposeThis chart is used for the apparent limestone porosity recorded by theAPS Accelerator Porosity Sonde or sidewall neutron porosity (SNP)tool to provide the equivalent porosity in sandstone or dolomite for-mations. It can also be used to obtain the apparent limestone poros-ity (used for the various crossplot porosity charts) for a log recordedin sandstone or dolomite porosity units.
DescriptionEnter the x-axis with the corrected near-to-array apparent limestoneporosity (APLC) or near-to-far apparent limestone porosity (FPLC)and move vertically to the appropriate lithology curve. Then read theequivalent porosity on the y-axis. For APS porosity recorded in sand-stone or dolomite porosity units enter that value on the y-axis andmove horizontally to the recorded lithology curve. Then read theapparent limestone neutron porosity for that point on the x-axis.
The APLC is the epithermal short-spacing apparent limestoneneutron porosity from the near-to-array detectors. The log is auto-matically corrected for standoff during acquisition. Because it isepithermal this measurement does not need environmental correc-tions for temperature or chlorine effect. However, corrections formud weight and actual borehole size should be applied (see ChartNeu-10). The short spacing means that the effect of density andtherefore the lithology on this curve is minimal.
The FPLC is the epithermal long-spacing apparent limestone neu-tron porosity acquired from the near-to-far detectors. Because it isepithermal this measurement does not need environmental correc-tions for temperature or chlorine effect. However, corrections formud weight and actual borehole size should be applied (see ChartNeu-10). The long spacing means that the density and thereforelithology effect on this curve is pronounced, as seen on Charts Por-13and Por-14.
The HPLC curve is the high-resolution version of the APLC curve.The same corrections apply.
Example: Equivalent PorosityGiven: APLC = 25 p.u. and FPLC = 25 p.u.
Find: Porosity for sandstone and for dolomite.
Answer: Sandstone porosity from APLC = 28.5 p.u. and sandstoneporosity from FPLC = 30 p.u.
Dolomite porosity = 24 and 20 p.u., respectively.
Example: Apparent PorosityGiven: Clean sandstone porosity = 20 p.u.
Find: Apparent limestone neutron porosity.
Answer: Enter the y-axis at 20 p.u. and move horizontally to the quartz sandstone matrix curves. Move verticallyfrom the points of intersection to the x-axis and readthe apparent limestone neutron porosity values. APLC = 16.8 p.u. and FPLC = 14.5 p.u.
APS* Near-to-Array (APLC) and Near-to-Far (FPLC) LogsEpithermal Neutron Porosity Equivalence—Open Hole
Resolution Short Spacing Long Spacing
Normal APLCFPLCEpithermal neutron porosity (ENPI)†
Enhanced HPLCHFLCHNPI†
† Not formation-salinity corrected.
Porosity—Wireline
206
Por
Porosity—Wireline
APS* Near-to-Array (APLC) and Near-to-Far (FPLC) LogsEpithermal Neutron Porosity Equivalence—Open Hole Por-4
(former Por-13a)
40
30
20
10
0 0 10 20 30 40
Apparent limestone neutron porosity, φSNPcor (p.u.) Apparent limestone neutron porosity, φAPScor (p.u.)
True porosity for indicated
matrix material, φ (p.u.)
Calcite(lim
estone)
Dolomite
APLCFPLCSNP
Quartzsa
ndstone
*Mark of Schlumberger© Schlumberger
Thermal Neutron ToolPorosity Equivalence—Open Hole
207
Por
GeneralPorosity—Wireline
PurposeThis chart is used to convert CNL* Compensated Neutron Log porositycurves (TNPH or NPHI) from one lithology to another. It can also beused to obtain the apparent limestone porosity (used for the variouscrossplot porosity charts) from a log recorded in sandstone or dolomiteporosity units.
DescriptionTo determine the porosity of either quartz sandstone or dolomiteenter the chart with the either the TNPH or NPHI corrected apparent limestone neutron porosity (φCNLcor) on the x-axis. Movevertically to intersect the appropriate curve and read the porosity for quartz sandstone or dolomite on the y-axis. The chart has a built-in salinity correction for TNPH values.
ExampleGiven: Quartz sandstone formation, TNPH = 18 p.u. (apparent
limestone neutron porosity), and formation salinity =250,000 ppm.
Find: Porosity in sandstone.
Answer: From the TNPH porosity reading of 18 p.u. on the x-axis,project a vertical line to intersect the quartz sandstonedashed red curve. From the y-axis, the porosity of thesandstone is 24 p.u.
40
30
20
10
0 0 10 20 30 40
Apparent limestone neutron porosity, φCNLcor (p.u.)
True porosityfor indicated
matrix material,φ (p.u.)
Quartz
sand
stone
Calcite(lim
estone)
Dolomite
Formation salinity
TNPH
NPHI
0 ppm
250,000 ppm
NPHI Thermal neutron porosity (ratio method)NPOR Neutron porosity (environmentally corrected and
enhanced vertical resolution processed)TNPH Thermal neutron porosity (environmentally corrected)
Por-5(former Por-13b)
*Mark of Schlumberger© Schlumberger
208
Por
PurposeThis chart is used similarly to Chart Por-5 to convert 21⁄2-in. compen-sated neutron tool (CNT) porosity values (TNPH) from one lithologyto another. Fresh formation water is assumed.
Porosity—Wireline
Thermal Neutron Tool—CNT-D and CNT-S 21⁄2-in. ToolsPorosity Equivalence—Open Hole
40
30
20
10
0 –10 0 10 20 30 40
Sands
tone
DolomiteLim
estone
Apparent limestone neutron porosity (p.u.)
True porosityfor indicated
matrix material,φ (p.u.)
Por-6
© Schlumberger
209
Por
GeneralPorosity—LWD
adnVISION475* 4.75-in. Azimuthal Density Neutron ToolPorosity Equivalence—Open Hole Por-7
PurposeThis chart is used to determine the porosity of sandstone, limestone,or dolomite from the corrected apparent limestone porosity measuredwith the adnVISION475 4.75-in. tool.
DescriptionEnter the chart on the x-axis with the corrected apparent limestoneporosity from Chart Neu-31 to intersect the curve for the appropriateformation material. Read the porosity on the y-axis.
–5 0 5 10 15 20 25 30 35 40
40
35
30
25
20
15
10
5
0
Corrected apparent limestone neutron porosity, φADNcor (p.u.)
True porosityfor indicated
matrix material,φ (p.u.)
Quartz sandstone
Calcite (lim
estone)
Dolomite
*Mark of Schlumberger© Schlumberger
210
Por
PurposeChart Por-8 is used similarly to Chart Por-7 for determining porosity from the corrected apparent limestone porosity from the adnVISION675 6.75-in. tool.
Porosity—LWD
adnVISION675* 6.75-in. Azimuthal Density Neutron ToolPorosity Equivalence—Open Hole Por-8
–5 0 5 10 15 20 25 30 35 40
40
35
30
25
20
15
10
5
0
Corrected apparent limestone neutron porosity, φADNcor (p.u.)
True porosity for indicated
matrix material, φ (p.u.)
Quartz sandstone
Calcite (lim
estone)
Dolomite
*Mark of Schlumberger© Schlumberger
211
Por
PurposeChart Por-9 is used similarly to Chart Por-7 for determining porosity from the corrected apparent limestone porosity from the adnVISION825 8.25-in. tool.
Porosity—LWD
adnVISION825* 8.25-in. Azimuthal Density Neutron ToolPorosity Equivalence—Open Hole Por-9
–5 0 5 10 15 20 25 30 35 40
40
35
30
25
20
15
10
5
0
Corrected apparent limestone neutron porosity, φADNcor (p.u.)
True porosity (p.u.)
Sandstone
Limestone
Dolomite
*Mark of Schlumberger© Schlumberger
212
Por
Porosity—Wireline
CNL* Compensated Neutron Log and Litho-Density* Tool (fresh water in invaded zone)Porosity and Lithology—Open Hole
PurposeThis chart is used with the bulk density and apparent limestoneporosity from the CNL Compensated Neutron Log and Litho-Densitytools, respectively, to approximate the lithology and determine thecrossplot porosity.
DescriptionEnter the chart with the environmentally corrected apparent neu-tron limestone porosity on the x-axis and bulk density on the y-axis.The intersection of the two values describes the crossplot porosityand lithology.
If the point is on a lithology curve, that indicates that the forma-tion is primarily that lithology. If the point is between the lithologycurves, then the formation is a mixture of those lithologies. The posi-tion of the point in relation to the two lithology curves as composi-tion endpoints indicates the mineral percentages of the formation.
The porosity for a point between lithology curves is determinedby scaling the crossplot porosity by connecting similar numbers onthe two lithology curves (e.g., 20 on the quartz sandstone curve to 20 on the limestone curve). The scale line closest to the point repre-sents the crossplot porosity.
Chart Por-12 is used for the same purpose as this chart for salt-water-invaded zones.
ExampleGiven: Corrected apparent neutron limestone porosity =
16.5 p.u. and bulk density = 2.38 g/cm3.
Find: Crossplot porosity and lithology.
Answer: Crossplot porosity = 18 p.u. The lithology is approxi-mately 40% quartz and 60% limestone.
213
Por
GeneralPorosity—Wireline
CNL* Compensated Neutron Log and Litho-Density* Tool (fresh water in invaded zone)Porosity and Lithology—Open Hole
Por-11(former CP-1e)
0 10 20 30 40Corrected apparent limestone neutron porosity, φCNLcor (p.u.)
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
Bulkdensity,
ρb (g/cm3)
Densityporosity,φD (p.u.)
(ρma = 2.71 g/cm3,ρf = 1.0 g/cm3)
45
40
35
30
25
20
15
10
5
0
–5
–10
–15Anhydrite
SulfurSalt
ApproximategascorrectionPorosity
Calcite (lim
estone)
0
5
10
15
20
25
30
35
40
45
Quartz sandstone
0
5
10
15
20
25
30
35
40
Dolomite
0
5
10
15
20
25
30
35
Liquid-Filled Borehole (ρf = 1.000 g/cm3 and Cf = 0 ppm)
*Mark of Schlumberger© Schlumberger
214
Por
GeneralPorosity—Wireline
PurposeThis chart is used similarly to Chart Por-11 with CNL CompensatedNeutron Log and Litho-Density values to approximate the lithologyand determine the crossplot porosity in the saltwater-invaded zone.
ExampleGiven: Corrected apparent neutron limestone porosity =
16.5 p.u. and bulk density = 2.38 g/cm3.
Find: Crossplot porosity and lithology.
Answer: Crossplot porosity = 20 p.u. The lithology is approxi-mately 55% quartz and 45% limestone.
CNL* Compensated Neutron Log and Litho-Density* Tool (salt water in invaded zone)Porosity and Lithology—Open Hole
Por-12(former CP-11)
0 10 20 30 40
Corrected apparent limestone neutron porosity, φCNLcor (p.u.)
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
Bulkdensity,
ρb (g/cm3)
Densityporosity,φD (p.u.)
(ρma = 2.71 g/cm3,ρf = 1.19 g/cm3)
45
40
35
30
25
20
15
10
5
0
–5
–10
–15
Liquid-filled borehole (ρf = 1.190 g/cm3 and Cf = 250,000 ppm)
0
5
10
15
20
25
30
35
40
45
0
5
10
15
20
25
30
35
0
5
10
15
20
25
30
35
40
45
Approximategascorrection
Porosity
Quartz sandstone
Calcite (limestone)
SulfurSalt
Dolomite
Anhydrite
*Mark of Schlumberger© Schlumberger
215
Por
GeneralPorosity—Wireline
APS* and Litho-Density* ToolsPorosity and Lithology—Open Hole Por-13
(former CP-1g)
PurposeThis chart is used to determine the lithology and porosity from theLitho-Density bulk density and APS Accelerator Porosity Sonde porositylog curves (APLC or FPLC). This chart applies to boreholes filledwith freshwater drilling fluid; Chart Por-14 is used for saltwater fluids.
DescriptionEnter either the APLC or FPLC porosity on the x-axis and the bulkdensity on the y-axis. Use the blue matrix curves for APLC porosityvalues and the red curves for FPLC porosity values. Anhydrite plotson separate curves. The gas correction direction is indicated for for-mations containing gas. Move parallel to the blue correction line ifthe APLC porosity is used or to the red correction line if the FPLCporosity is used.
ExampleGiven: APLC porosity = 8 p.u. and bulk density = 2.2 g/cm3.
Find: Approximate quartz sandstone porosity.
Answer: Enter at 8 p.u. on the x-axis and 2.2 g/cm3 on the y-axisto find the intersection point is in the gas-in-formationcorrection region. Because the APLC porosity value wasused, move parallel to the blue gas correction line untilthe blue quartz sandstone curve is intersected at approx-imately 19 p.u.
Liquid-Filled Borehole (ρf = 1.000 g/cm3 and Cf = 0 ppm)
Bulk density,ρb (g/cm3)
Corrected APS apparent limestone neutron porosity, φAPScor (p.u.)
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0 0 10 20 30 40
APLCFPLC
Anhydrite
DolomiteCalcite (lim
estone)
Quartz sandstone
Porosity
Approximategascorrection
0
5
5
10
10
15
15
20
20
25
25
35
3530
30
40
40
45
0
5
40
35
30
25
20
15
10
0
35
30
25
20
15 15
10
5
0
0
10
20
30
35
40
5
25
*Mark of Schlumberger© Schlumberger
216
Por
GeneralPorosity—Wireline
PurposeThis chart is used similarly to Chart Por-13 to determine the lithologyand porosity from Litho-Density* bulk density and APS* porosity logcurves (APLC or FPLC) in saltwater boreholes.
ExampleGiven: APLC porosity = 8 p.u. and bulk density = 2.2 g/cm3.
Find: Approximate quartz sandstone porosity.
Answer: Enter 8 p.u. on the x-axis and 2.2 g/cm3 on the y-axis tofind the intersection point is in the gas-in-formation cor-rection region. Because the APLC porosity value wasused, move parallel to the blue gas correction line untilthe blue quartz sandstone curve is intersected at approx-imately 20 p.u.
APS* and Litho-Density* Tools (saltwater formation)Porosity and Lithology—Open Hole Por-14
(former CP-1h)
Liquid-Filled Borehole (ρf = 1.190 g/cm3 and Cf = 250,000 ppm)
Bulk density,ρb (g/cm3)
Corrected APS apparent limestone neutron porosity, φAPScor (p.u.)
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.00 10 20 30 40
Anhydrite
Porosity
Approximategascorrection
0
0
5
5
10
10
15
15
20
20
25
25
35
3530
30
40
40
45
0
5
40
35
30
25
20
15
10
0
40
35
30
25
20
15
10
5
0
4545
APLCFPLC
5
10
15
20
25
30
35
40
Quartz sandstone
DolomiteCalcite (limestone)
*Mark of Schlumberger© Schlumberger
217
Por
GeneralPorosity—LWD
adnVISION475* 4.75-in. Azimuthal Density Neutron ToolPorosity and Lithology—Open Hole Por-15
PurposeThis chart is used to determine the crossplot porosity and lithologyfrom the adnVISION475 4.75-in. density and neutron porosity.
DescriptionEnter the chart with the adnVISION475 corrected apparent lime-stone neutron porosity (from Chart Neu-31) and bulk density. Theintersection of the two values is the crossplot porosity. The positionof the point of intersection between the matrix curves represents therelative percentage of each matrix material.
ExampleGiven: φADNcor = 20 p.u. and ρb = 2.24 g/cm3.
Find: Crossplot porosity and matrix material.
Answer: 25 p.u. in sandstone.
Bulk density,ρb (g/cm3)
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
Anhydrite
Salt
Corrected apparent limestone neutron porosity, φADNcor (p.u.)
–5 0 5 10 15 20 25 30 35 40 45
Fresh Water, Liquid-Filled Borehole (ρf = 1.0 g/cm3)
DolomiteCalcite (lim
estone)Quartz
sandstone
Porosity
0
0
5
10
10
15
15
20
20
25
25
35
3530
30
40
40
40
35
30
25
20
15
10
5
05
*Mark of Schlumberger© Schlumberger
Por
218
GeneralPorosity—LWD
PurposeThis chart uses the bulk density and apparent limestone porosity fromthe adnVISION 6.75-in. Azimuthal Density Neutron tool to determinethe lithology of the logged formation and the crossplot porosity.
DescriptionThis chart is applicable for logs obtained in freshwater drilling fluid. Enter the corrected apparent limestone porosity and the bulkdensity on the x- and y-axis, respectively. Their intersection pointdetermines the lithology and crossplot porosity.
ExampleGiven: Corrected adnVISION675 apparent limestone porosity =
20 p.u. and bulk density = 2.3 g /cm3.
Find: Porosity and lithology type.
Answer: Entering the chart at 20 p.u. on the x-axis and 2.3 g /cm3
on the y-axis corresponds to a crossplot porosity of 21.5 p.u. and formation comprising approximately 60% quartz sandstone and 40% limestone.
adnVISION675* 6.75-in. Azimuthal Density Neutron ToolPorosity and Lithology—Open Hole Por-16
Corrected apparent limestone neutron porosity, φADNcor (p.u.)
Bulk density,ρb (g/cm3)
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0–5 0 5 10 15 20 25 30 35 40 45
Fresh Water, Liquid-Filled Borehole (ρf = 1.0 g/cm3)
DolomiteCalcite
(limestone)
Quartz sandstone
0
0
10
10
15
20
25
5
5
5
10
15
20
0
25
35
30
15
20
25
35
30
30
35
4 0
40
Porosity
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219
Por
GeneralPorosity—LWD
PurposeThis chart is used similarly to Chart Por-15 to determine the lithologyand crossplot porosity from adnVISION825 8.25-in. Azimuthal DensityNeutron values.
adnVISION825* 8.25-in. Azimuthal Density Neutron ToolPorosity and Lithology—Open Hole Por-17
Corrected apparent limestone neutron porosity, φADNcor (p.u.)
Bulk density,ρb (g/cm3)
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0–5 0 5 10 15 20 25 30 35 40 45
Fresh Water, Liquid-Filled Borehole (ρf = 1.0 g/cm3)
Calcite (lim
estone)
Quartz sandstone
0
10
5
Dolomite
5
10
15
20
0
25
35
30
15
20
25
35
30
40
0
10
15
20
5
30
35
40
25
Porosity 40
*Mark of Schlumberger© Schlumberger
220
Por
GeneralPorosity—Wireline
Sonic and Thermal Neutron CrossplotPorosity and Lithology—Open Hole, Freshwater Invaded
PurposeThis chart is used to determine crossplot porosity and an approxi-mation of lithology for sonic and thermal neutron logs in freshwaterdrilling fluid.
DescriptionEnter the corrected neutron porosity (apparent limestone porosity)on the x-axis and the sonic slowness time (∆t) on the y-axis to findtheir intersection point, which describes the crossplot porosity andlithology composition of the formation. Two sets of curves are drawnon the chart. The blue set of curves represents the crossplot porosityvalues using the sonic time-average algorithm. The red set of curvesrepresents the field observation algorithm.
ExampleGiven: Thermal neutron apparent limestone porosity = 20 p.u.
and sonic slowness time = 89 µs/ft in freshwater drilling fluid.
Find: Crossplot porosity and lithology.
Answer: Enter the neutron porosity on the x-axis and the sonicslowness time on the y-axis. The intersection point is atabout 25 p.u. on the field observation line and 24.5 p.u.on the time-average line. The matrix is quartz sandstone.
221
Por
GeneralGeneralPorosity—Wireline
Sonic and Thermal Neutron CrossplotPorosity and Lithology—Open Hole, Freshwater Invaded Por-20
(customary, former CP-2c)
0 10 20 30 40
110
100
90
80
70
60
50
40
Corrected CNL* apparent limestone neutron porosity, φCNLcor (p.u.)
Sonic transit time,∆t (µs/ft)
tf = 190 µs/ft and Cf = 0 ppm
Salt
Anhydrite
Dolomite
Calci
te (li
mesto
ne)
Quartz
sand
stone
Time averageField observation
Poros
ity
0
5
55
00
10
15
20
25
35
40
40
3535
30
3535
30
20
15
25
20
15
10
10
15
20
25
3030
0
5
10
10
15
15
20
2025
2530
30
0
5
0
5
25
10
*Mark of Schlumberger© Schlumberger
222
Por
GeneralPorosity—Wireline
Sonic and Thermal Neutron CrossplotPorosity and Lithology—Open Hole, Freshwater Invaded
Por-21(metric, former CP-2cm)
0 10 20 30 40
360
340
320
300
280
260
240
220
200
180
160
140
Corrected CNL* apparent limestone neutron porosity, φCNLcor (p.u.)
Sonic transit time,∆t (µs/m)
tf = 620 µs/m and Cf = 0 ppm
Salt
Anhyd
rite
Dolomite
Calci
te (li
mesto
ne)
Quartz
sand
stone
Time averageField observation
Poros
ity
0
5
55
00
10
15
20
35
40
40
35
30
353530
20
15
10
25
20
15
10
10
15
20
3030
0
5
10
10
15
15
20
20
25
2530
30
0
5
0
5
2525
35
25
PurposeThis chart is used similarly to Chart Por-20 for metric units.
*Mark of Schlumberger© Schlumberger
continued on next page
223
Por
GeneralGeneralPorosity—Wireline, LWD
Density and Sonic CrossplotPorosity and Lithology—Open Hole, Freshwater Invaded
PurposeThis chart is used to determine porosity and lithology for sonic anddensity logs in freshwater-invaded zones.
DescriptionEnter the chart with the bulk density on the y-axis and sonic slow-ness time on the x-axis. The point of intersection indicates the typeof formation and its porosity.
ExampleGiven: Bulk density = 2.3 g /cm3 and sonic slowness
time = 82 µs/ft.
Find: Crossplot porosity and lithology.
Answer: Limestone with a crossplot porosity = 24 p.u.
224
Por
GeneralPorosity—Wireline, LWD
Density and Sonic CrossplotPorosity and Lithology—Open Hole, Freshwater Invaded Por-22
(customary, former CP-7)
40 50 60 70 80 90 100 110 120
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
Sonic transit time, ∆t (µs/ft)
Bulk density,ρb (g/cm3)
tf = 189 µs/ft and ρf = 1.0 g/cm3
Dolomite
Calcite
(limes
tone)
Anhydrite
Polyhalite
Gypsum
Trona
Salt
Sylvite
Sulfur
0
10
10
10 20
30
4040 40 40
40
3030
20
0
0
0
0
10
0
Porosity
Time averageField observation
30
30
30
2020
20
1020
10
Quartz
sand
stone
© Schlumberger
225
Por
General
PurposeThis chart is used similarly to Chart Por-22 for metric units.
GeneralPorosity—Wireline, LWD
Density and Sonic CrossplotPorosity and Lithology—Open Hole, Freshwater Invaded Por-23
(metric, former CP-7m)
150 200 250 300 350 400
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
Sonic transit time, ∆t (µs/m)
Bulk density,ρb (g/cm3)
tf = 620 µs/m and ρf = 1.0 g/cm3
Dolomite
Calcite
(limes
tone)
Anhydrite
Polyhalite
Gypsum
Trona
Salt
Sylvite
Sulfur
0
10
10
10 20
20
20
30
40
30
40 40
40
3030
20
0
0
10
0
Porosity
30
0
0
10
Time averageField observation
30
10
Quartz
sand
stone
20
20
40
© Schlumberger
226
Por
GeneralPorosity—Wireline, LWD
Density and Neutron ToolPorosity Identification—Gas-Bearing Formation
PurposeThis chart is used to determine the porosity and average water satu-ration in the flushed zone (Sxo) for freshwater invasion and gas com-position of C1.1H4.2 (natural gas).
DescriptionEnter the chart with the neutron- and density-derived porosity values(φNand φD, respectively). On the basis of the table, use the blue curvesfor shallow reservoirs and the red curves for deep reservoirs.
ExampleGiven: φD = 25 p.u. and φN = 10 p.u. in a low-pressure, shallow
(4,000-ft) reservoir.
Find: Porosity and Sxo.
Answer: Enter the chart at 25 p.u. on the y-axis and 10 p.u. on thex-axis. The point of intersection identifies (on the bluecurves for a shallow reservoir) φ = 20 p.u. and Sxo = 62%.
Depth Pressure Temperature ρw (g/cm3) IHw ρg (g/cm3) IHg
Shallow reservoir ~2,000 psi [~14,000 kPa] ~120°F [~50°C] 1.00 1.00 0 0Deep reservoir ~7,000 psi [~48,000 kPa] ~240°F [~120°C] 1.00 1.00 0.25 0.54
ρw = density of water, ρg = density of gas, IHw = hydrogen index of water, and IHg = hydrogen index of gas
227
Por
GeneralGeneralGeneralPorosity—Wireline, LWD
Density and Neutron ToolPorosity Identification—Gas-Bearing Formation Por-24
(former CP-5)
Neutron-derived porosity, φN (p.u.)
Density-derived porosity,φD (p.u.)
50
40
30
20
10
0 0 10 20 30 40
Sxo
Sxo
15
20
Porosity
30
80
35
025
40
55
15
10
20
100
30
25
60
40
60
20
100
80
35
40
20
0
10
For shallow reservoirs, use blue curves.For deep reservoirs, use red curves.
© Schlumberger
228
Por
General
PurposeThis chart is used to determine the porosity and average water satu-ration in the flushed zone (Sxo) for freshwater invasion and gas com-position of CH4 (methane).
DescriptionEnter the chart with the APS Accelerator Porosity Sonde neutron- anddensity-derived porosity values (φN and φD, respectively). On the basisof the table, use the blue curves for shallow reservoirs and the redcurves for deep reservoirs.
ExampleGiven: φD = 15 p.u. and APS φN = 8 p.u. in a normally pressured
deep (14,000-ft) reservoir.
Find: Porosity and Sxo.
Answer: φ = 11 p.u. and Sxo = 39%.
Porosity—Wireline
Density and APS* Epithermal Neutron ToolPorosity Identification—Gas-Bearing Formation
Depth Pressure Temperature ρw IHw ρg IHg
Shallow reservoir ~2,000 psi [~14,000 kPa] ~120°F [~50°C] 1.00 1.00 0.10 0.23Deep reservoir ~7,000 psi [~48,000 kPa] ~240°F [~120°C] 1.00 1.00 0.25 0.54
ρw = density of water, ρg = density of gas, IHw = hydrogen index of water, and IHg = hydrogen index of gas
229
Por
GeneralGeneralGeneralPorosity—Wireline
Density and APS* Epithermal Neutron ToolPorosity Identification—Gas-Bearing Formation Por-25
(former CP-5a)
Density-derived porosity,φD (p.u.)
For shallow reservoirs, use blue curves.For deep reservoirs, use red curves.
0 10 20 30 40
APS epithermal neutron-derived porosity, φN (p.u.)
50
40
30
20
10
0
55
1515
2020
40
3030
40
80
35
35
2525
40
20
0
100Sxo
Sxo
80100
200
6040
60
Porosity
1010
*Mark of Schlumberger© Schlumberger
230
Por
General
PurposeThis nomograph is used to estimate porosity in hydrocarbon-bearingformations by using density, neutron, and resistivity in the flushedzone (Rxo) logs. The density and neutron logs must be corrected forenvironmental effects and lithology before entry to the nomograph.The chart includes an approximate correction for excavation effect,but if hydrocarbon density (ρh) is <0.25 g /cm3 (gas), the chart maynot be accurate in some extreme cases:
very high values of porosity (>35 p.u.) coupled with medium to high values of hydrocarbon saturation (Shr)
Shr = 100% for medium to high values of porosity.
DescriptionConnect the apparent neutron porosity value on the appropriateneutron porosity scale (CNL* Compensated Neutron Log or sidewallneutron porosity [SNP] log) with the corrected apparent densityporosity on the density scale with a straight line. The intersectionpoint on the φ1 scale indicates the value of φ1.
Draw a line from the φ1 value to the origin (lower right corner) of the chart for ∆φ versus Shr.
Enter the chart with Shr from (Shr = 1 – Sxo) and move verticallyupward to determine the porosity correction factor (∆φ) at the inter-section with the line from the φ1 scale.
This correction factor algebraically added to the porosity φ1 givesthe corrected porosity.
ExampleGiven: Corrected CNL apparent neutron porosity = 12 p.u.,
corrected apparent density porosity = 38 p.u., and Shr = 50%.
Find: Hydrocarbon-corrected porosity.
Answer: Enter the 12-p.u. φcor value on the CNL scale. A line fromthis value to 38 p.u. on the φDcor scale intersects the φ1
scale at 32.2 p.u. The intersection of a line from thisvalue to the graph origin and Shr = 50% is ∆φ = –1.6 p.u.Hydrocarbon-corrected porosity: 32.2 – 1.6 = 30.6 p.u.
GeneralGeneralPorosity—Wireline
Density, Neutron, and Rxo LogsPorosity Identification in Hydrocarbon-Bearing Formation—Open Hole
231
Por
GeneralGeneralGeneralPorosity—Wireline
Density, Neutron, and Rxo LogsPorosity Identification in Hydrocarbon-Bearing Formation—Open Hole Por-26
(former CP-9)
–5
–4
–3
–2
–1
0100 80 60 40 20 0
Shr (%)
∆φ (p.u.)
φDcor
50
40
30
20
10
0
φ1
50
40
30
20
10
0
φcor
(SNP)
50
40
30
20
10
0
φcor
(CNL*)
50
40
30
20
10
0
(p.u.)
*Mark of Schlumberger© Schlumberger
232
Por
GeneralPorosity—Wireline
Hydrocarbon Density EstimationPor-27
(former CP-10)
1.0
0.8
0.6
0.4
0.2
0
φCNLcor
φDcor
0 20 40 60 80 100
0.8ρh
0.7
0.6
0.5
0.40.3
0.20.10
Shr (%)
1.0
0.8
0.6
0.4
0.2
0 0 20 40 60 80 100
0.8ρh
0.7
0.6
0.5
0.4
0.3
0.20.10
Shr (%)
φSNPcor
φDcor
*Mark of Schlumberger© Schlumberger
PurposeThis chart is used to estimate the hydrocarbon density (ρh) within a formation from corrected neutron and density porosity values.
DescriptionEnter the ratio of the sidewall neutron porosity (SNP) or CNL* Compensated Neutron Log neutron porosity and density porosity corrected for lithology and environmental effects (φSNPcor or φCNLcor /φDcor, respectively) on the y-axis and the
hydrocarbon saturation on the x-axis. The intersection point of thetwo values defines the density of the hydrocarbon.
ExampleGiven: Corrected CNL porosity = 15 p.u., corrected density
porosity = 25 p.u., and Shr = 30% (residual hydrocarbon).
Find: Hydrocarbon density.
Answer: Porosity ratio = 15/25 = 0.6. ρh = 0.29 g /cm3.
233
SatOH
General
log = . – .RR
mf
mm
⎛⎝⎜
⎞⎠⎟
×( )0 396 0 0475 ρ
Saturation—Wireline, LWD
Porosity Versus Formation Resistivity FactorOpen Hole SatOH-1
(former Por-1)
PurposeThis chart is used for a variety of conversions of the formation resistivity factor (FR) to porosity.
DescriptionThe most appropriate conversion is best determined by laboratorymeasurement or experience in the area. In the absence of thisknowledge, recommended relationships are the following:
Soft formations (Humble formula): FR = 0.62/φ2.51 or Fr = 0.81/φ2
Hard formations: FR = 1/φm with the appropriate cementationfactor (m).
ExampleGiven: Soft formation with Hard formation (m = 2) with
φ = 25 p.u. φ = 8 p.u.
Find: FR. FR.
Answer: FR = 13 (from chart). FR = 160 (from chart).
FR = 12.96 (calculated). FR = 156 (calculated).
2.5 5 10 20 50 100 200 500 1,000 2,000 5,000 10,000
2.5 5 10 20 50 100 200 500 1,000 2,000 5,000 10,00050
40
30
25
20
15
10987
6
5
4
3
2
1
Formation resistivity factor, FR
Porosity,φ (p.u.)
1.4
1.6
1.82.0
2.2
2.5
2.8
FR = 0.81φ2
FR = 1φ2
FR = 0.62φ2.15
FR = 1φmm
Fractures
Vugs orspherical pores
© Schlumberger
PurposeThis chart is used to identify how much of the measured porosity is isolated (vugs or moldic) or fractured porosity.
DescriptionThis chart is based on a simplified model that assumes no contribu-tion to formation conductivity from vugs and moldic porosity and thecementation exponent (m) of fractures is 1.0.
When the pores of a porous formation have an aspect ratio closeto 1 (vugs or moldic porosity), the value of m of the formation is usu-ally greater than 2. Fractured formations typically have a cementa-tion exponent less than 2.
Enter the chart with the porosity (φ) on the x-axis and m on the y-axis. The intersection point gives an estimate of either the amountof isolated porosity (φiso) or the amount of porosity resulting fromfractures (φfr).
ExampleGiven: φ = 10 p.u. and cementation exponent = 2.5.
Find: Intergranular (matrix) porosity.
Answer: Entering the chart with 10 p.u. and 2.5 gives an intersec-tion point of φiso = approximately 4.5 p.u. Intergranular porosity = 10 – 4.5 = 5.5 p.u.
Saturation—Wireline, LWD
Spherical and Fracture PorosityOpen Hole SatOH-2
(former Por-1a)
0.5 0.8 1 2 4 6 8 10 20 30 40 50Porosity, φ (p.u.)
3.0
2.5
2.0
1.5
1.0
Cementationexponent, m
Fractures
φ fr = 0.1
0.2
2.5
10.0
0.5
1.0
1.5 2.0
5.0
φiso = 0.5
1.01.5
2.55.0
7.510.0
12.5
2.0Isolated
pores
234
SatOH
© Schlumberger
SatOH
235
Saturation—Wireline, LWD
Saturation DeterminationOpen Hole
PurposeThis nomograph is used to solve the Archie water saturation equation:
whereSw = water saturation
Ro = resistivity of clean-water formation
Rt = true resistivity of the formation
FR = formation resistivity factor
Rw = formation water resistivity.
It should be used in clean (nonshaly) formations only.
DescriptionIf Ro is known, a straight line from the known Ro value through themeasured Rt value indicates the value of Sw. If Ro is unknown, it maybe determined by connecting Rw with FR or porosity (φ).
ExampleGiven: Rw = 0.05 ohm-m at formation temperature, φ = 20 p.u.
(FR = 25), and Rt = 10 ohm-m.
Find: Water saturation.
Answer: Enter the nomograph on the Rw scale at Rw = 0.05 ohm-m.
Draw a straight line from 0.05 through the porosity scaleat 20 p.u. to intersect the Ro scale.
From the intersection point of Ro = 1, draw a straight linethrough Rt = 10 ohm-m to intersect the Sw scale.
Sw = 31.5%.
SR
R
F R
Rwo
t
R w
t= = ,
continued on next page
236
SatOH
Saturation—Wireline, LWD
Saturation DeterminationOpen Hole SatOH-3
(former Sw-1)
Rw(ohm-m)
Ro(ohm-m)
Ro = FRRw
Rt(ohm-m)
Sw(%)
φ(%)
FR
2,000
1,000800600400300200
100806050403020
108654
2.53
4
56789
10
15
20
253035404550
FR = 1φ2.0
m = 2.0
0.01
0.02
0.03
0.04
0.050.060.070.080.090.1
0.2
0.3
0.4
0.50.60.70.80.91
1.5
2
5
6
7
8
9
10111213141516
1820
25
30
40
50
60
70
80
90100
10,0008,0006,0005,0004,0003,0002,000
1,000800600500400300200
100806050403020
10865432
1.00.80.60.50.40.30.2
0.1
30
20181614121098765
4
3
21.81.61.41.21.00.90.80.70.60.5
0.4
0.3
0.20.180.160.140.120.10
Clean Formations, m = 2
Sw = RoRt
© Schlumberger
237
SatOH
Saturation—Wireline, LWD
Saturation DeterminationOpen Hole
PurposeThis chart is used to determine water saturation (Sw) in shaly orclean formations when knowledge of the porosity is unavailable. Itmay also be used to verify the water saturation determination fromanother interpretation method. The large chart assumes that themud filtrate saturation is
The small chart provides an Sxo correction when Sxo is known.However, water activity correction is not provided for the SP portionof the chart (see Chart SP-2).
Description Clean SandsEnter the large chart with the ratio of the resistivity of the flushedzone to the true formation resistivity (Rxo /Rt) on the y-axis and theratio of the resistivity of the mud filtrate to the resistivity of the for-mation water (Rmf /Rw) on the x-axis to find the water saturation ataverage residual oil saturation (Swa). If Rmf/Rw is unknown, the chartmay be entered with the spontaneous potential (SP) value and theformation temperature. If Sxo is known, move diagonally upward,parallel to the constant-Swa curves, to the right edge of the chart.Then, move horizontally to the known Sxo (or residual oil saturation[ROS], Sor) value to obtain the corrected value of Sw.
ExampleGiven: Rxo = 12 ohm-m, Rt = 2 ohm-m, Rmf/Rw = 20, and
Sor = 20%.
Find: Sw (after correction for ROS).
Answer: Enter the large chart at Rxo/Rt = 12/2 = 6 on the y-axis and Rmf/Rw = 20 on the x-axis. From the point ofintersection (labeled A), move diagonally to the right tointersect the chart edge and directly across to enter thesmall chart and intersect Sor = 20%.
Sw = 43%.
Description Shaly SandsEnter the chart with Rxo/Rt and the SP in the shaly sand (EPSP). Thepoint of intersection gives the Swa value. Draw a line from the chart’sorigin (the small circle located at Rxo/Rt = Rmf/Rm = 1) through thispoint to intersect with the value of static spontaneous potential (ESSP)to obtain a value of Rxo/Rt corrected for shaliness. This value of Rxo/Rt
versus Rmf/Rw is plotted to find Sw if Rmf/Rw is unknown because thepoint defined by Rxo/Rt and ESSP is a reasonable approximation of Sw.The small chart to the right can be used to further refine Sw if Sor isknown.
ExampleGiven: Rxo/Rt = 2.8, Rmf/Rw = 25, EPSP = –75 mV, ESSP = –120 mV,
and electrochemical SP coefficient (Kc) = 80 (formationtemperature = 150ºF).
Find: Sw and corrected value for Sor = 10%.
Answer: Enter the large chart at Rxo/Rt = 2.8 and the intersectionof EPSP = –75 mV at Kc = 80 from the chart below. A linefrom the origin through the intersection point (labeled B)intersects the –120-mV value of ESSP at Point C. Movehorizontally to the left to intersect Rmf/Rw = 25 at Point D.Then move diagonally to the right to intersect the righty-axis of the chart. Move horizontally to the small chart todetermine Sxo = 0.9%, Sw = 38%, and corrected Sw = 40%.
For more information, see Reference 12.
S Sxo w= 5 .
continued on next page
238
SatOH
Saturation—Wireline, LWD
Saturation DeterminationOpen Hole SatOH-4
(former Sw-2)
50
40
30
20
10
8
65
4
3
2
1
0.8
0.60.5
0.4
0.3
0.2
0.1
0.08
75100150200
300
0.80.6 1.0 1.5 2.52 3 4 5 6 8 10 15 20 25 30 40 50 60
20 10 0 –20 –40 –60 –80 –100 –120 –140
0.80.6 1.0 1.5 2.52 3 4 5 6 8 10 15 20 25 40 50 6030
255075100150
80
0 10 20 30 40
1.0 0.9 0.8 0.7 0.6
80
70
60
50
40
30
25
20
15
10
60
50
40
25
30
20
15
70
90100
Rmf/Rw
Rxo
Rt
Rmf/RwKc
Temperature(°F)
Temperature(°C)
EPSP or ESSP (mV)
Sxo
Sw = Sxo (Swa)0.8
Sor (%)
Sw (%)
A
B
CD
10%
15%
20%
25%30%
40%
50%60%70%
S wa = 10
0%
EPSP = –Kc log – 2Kc log Rxo
Rt
Sxo
Sw
Sxo = S w5
Sxo = S w5
© Schlumberger
239
SatOH
Saturation—Wireline, LWD
Graphical Determination of Sw from Swt and SwbOpen Hole SatOH-5
(former Sw-14)
PurposeThis chart is used to drive a value of water saturation (Sw) correctedfor the bound-water volume in shale.
DescriptionThis is a graphical determination of Sw from the total water satura-tion (Swt) and the saturation of bound water (Swb):
Enter the y-axis with Swt and move horizontally to intersect the appropriate Swb curve. Read the value of Sw on the x-axis.
ExampleGiven: Swt = 45% and Swb = 10%.
Find: Sw.
Answer: Sw = 39.5%.
100
90
80
70
60
50
40
30
20
10
00 10 20 30 40 50 60 70 80 90 100
Sw (%)
Swt (%)
Swb
70%
60%
50%
40%
30%
20%
10%
0
SS S
Swwt wb
wb=
−−1
.
© Schlumberger
240
SatOH
Saturation—Wireline, LWD
Porosity and Gas Saturation in Empty HoleOpen Hole SatOH-6
(former Sw-11)
2.65
2.70
2.75
2.80
2.85
2.90
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
Neutronporosity
index(corrected
for lithology)
Matrix density,ρma (g/cm3)
2.6 2.5 2.4 2.3 2.2 2.1 2.0 1.9 1.8
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30
SandstoneLimy sandstoneLimestone
Dolomite
2.8 2.7 2.6 2.5 2.4 2.3 2.2 2.1 2.0 1.9
Apparent bulk density from density log, ρb (g/cm3)
Porosity, φ (p.u.)
Density and Hydrogen Index of Gas Assumed ZeroUse if noshale present
Use if nooil present
100
90
80
70
60
50
40
30
20
10
0Ga
s sat
urat
ion,
Sg (
%)
10,0004,0002,0001,000400300200150
100
706050
40
30
20
1514131211
Rt
Rw
PurposeThis chart is used to determine porosity (φ) and gas saturation (Sg)from the combination of density and neutron or from density andresistivity measurements.
DescriptionEnter from the point of intersection of the matrix density (ρma) andapparent bulk density (ρb). Move vertically upward to intersecteither neutron porosity (φN, corrected for lithology) or the ratio oftrue resistivity to connate water resistivity (Rt/Rw). This point definesthe actual porosity and Sg on the curves.
Oil saturation (So) can also be determined if all three measure-ments (density, neutron, and resistivity) are available. Find the valuesof φ and Sg as before, and then find the intersection of Rt/Rw with φto read the value of the total hydrocarbon saturation (Sh) on the saturation scale for use in the following equations:
So = Sh – Sg
Sw = 100 – Sh.
ExampleGiven: Limy sandstone (ρma = 2.68 g/cm3), ρb = 2.44 g /cm3,
φN = 9 p.u., Rt = 74 ohm-m, and Rw = 0.1 ohm-m.
Find: φ, Sg, Sh, So, and Sw.
Answer: First, find Rt/Rw = 74/0.1 = 740.
φ = 12 p.u. and Sg = 25%.
Sh = 70% (total hydrocarbon saturation).
So = 70 – 25 = 45%.
Sw = 100 – 70 = 30%.
© Schlumberger
241
SatOH
PurposeThis nomograph is used to define flushed zone saturation (Sxo) in the rock immediately adjacent to the borehole by using the EPTElectromagnetic Propagation Tool time measurement (tpl).
DescriptionUse of this chart requires knowledge of the reservoir lithology ormatrix propagation time (tpma), saturating water propagation time(tpw), porosity (φ), and expected hydrocarbon type. Enter the far-leftscale with tpl and move parallel to the diagonal lines to intersect theappropriate tpma value. From this point move horizontally to the right
edge of the scale grid. From this point, extend a straight line throughthe porosity scale to the center scale grid; again, move parallel to thediagonal lines to the appropriate tpma value and then horizontally tothe right edge of the grid scale. From this point, extend a straightline through the intersection of tpw and the hydrocarbon type pointto intersect the Sxo scale. For more information, see Reference 25.
Saturation—Wireline
EPT* Propagation TimeOpen Hole SatOH-7
(former Sxo-1)
7 8 9 10tpma (ns/m)
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
7 8 9 10tpma (ns/m)
Sxo(%)
Sandstone
50454035
3025
2015
105
tpl (ns/m)
10.9
100
90
80
70
60
50
40
30
20
10
0
53%
tpw (ns/m)21
25
30
3540
50
6070
8090
GasOilFo
rmat
ion po
rosit
y (%
)
Limestone
Dolomite
Sandstone Limestone
Dolomite*Mark of Schlumberger© Schlumberger
242
SatOH
Saturation—Wireline
EPT* AttenuationOpen Hole SatOH-8
(former Sxo-2)
Aw(dB/m)
AEPTcor(dB/m)
Sxo(%)
φ(p.u.)
6,000
5,000
4,000
3,000
2,000
1,000900800700600
500
400
300
200
1009080
2
34
68
1
10
20
3040
6080100
200
300400
6008001,000
5
6
7
8910
20
30
40
50
60
70
8090100
1
2
345
10
1520
3040
PurposeThis nomograph is used to determine the flushed zone saturation(Sxo) in the rock immediately adjacent to the borehole by using theEPT Electromagnetic Propagation Tool attenuation measurement. Itrequires knowledge of the saturating fluid (usually mud filtrate)attenuation (Aw), porosity (φ), and the EPT EATT attenuation(AEPTcor) corrected for spreading loss.
DescriptionThe value of Aw must first be determined. Chart Gen-16 is used toestimate Aw by using the equivalent water salinity and formationtemperature. EPT-D spreading loss is determined from the inset onChart Gen-16 based on the uncorrected EPT propagation time (tpl)measurement. The spreading loss correction algebraically added tothe EPT-D EATT attenuation measurement gives the corrected EPTattenuation (AEPTcor). These values are used with porosity on thenomograph to determine Sxo.
ExampleGiven: EATT = 250 dB/m, tpl = 10.9 ns/m, φ = 28 p.u., water salin-
ity = 20,000 ppm, and bottomhole temperature = 150ºF.
Find: Spreading loss (from Chart Gen-16 inset) and Sxo.
Answer: The spreading loss determined from the inset on Chart Gen-16 is –82 dB/m.
AEPTcor = 250 – 82 = 168 dB/m.
Aw (from Chart Gen-16) = 1,100 dB/m.
Enter the far-left scale at Aw = 1,100 dB/m and draw a straight line through φ = 28 p.u. on the next scale tointersect the median line. From this intersection point,draw a straight line through AEPTcor = 168 dB/m on thenext scale to intersect the Sxo value on the far-rightscale. Sxo = 56 p.u.
*Mark of Schlumberger© Schlumberger
SatOH
PurposeThis chart is used to determine water saturation (Sw) from capturecross section, or sigma (Σ), measurements from the TDT* ThermalDecay Time pulsed neutron log.
DescriptionThis chart uses sigma water (Σw), matrix capture cross section (Σma),and porosity (φ) to determine water saturation in clean formations.The chart may be used in shaly formations if sigma shale (Σsh), thevolume fraction of shale in the formation (Vsh), and the porosity cor-rected for shale are known.
Thermal decay time (t and tsh in shale) is also shown on some of the chart scales because it is related to Σ.
ProcedureClean FormationThe Sw determination for a clean formation requires values knownfor Σma (based on lithology), φ, Σw from the NaCl salinity (see ChartGen-12 or Gen-13), and sigma hydrocarbon (Σh) (see Chart Gen-14).Enter the value of Σma on Scale B and draw a line to Pivot Point B.Enter Σlog on Scale B and draw Line b through the intersection ofLine a and the value of φ to intersect the sigma of the formationfluid (Σf) on Scale C. Draw Line 5 from Σf through the intersectionof Σh and Σw to determine the value of Sw on Scale D.
Example: Clean FormationGiven: Σlog = 20 c.u., Σma = 8 c.u. (sandstone) from TDT tool,
Σh = 18 c.u., Σw = 80 c.u. (150,000 ppm or mg/kg), and φ = 30 p.u.
Find: Sw.
Answer: Following the procedure for a clean formation, Sw = 43%.
ProcedureShaly FormationThe Sw determination in a shaly formation requires additional infor-mation: sigma shale (Σsh) read from the TDT log in adjacent shale,Vsh from porosity-log crossplot or gamma ray, shale porosity (φsh) readfrom a porosity log in adjacent shale, and the porosity corrected forshaliness (φshcor) with the relation for neutron and density logs in liquid-filled formations of φshcor = φlog – Vshφsh.
Enter the value of Σma on Scale B and draw Line 1 to intersectwith Pivot Point A. From the value of Σsh on Scale A, draw Line 2through the intersection of Line 1 and Vsh to determine the shale-corrected Σcor on Scale B. Draw Line 3 from Σcor to the value of Σma
on the scale to the left of Scale C. Enter Σlog on Scale B and drawLine 4 through the intersection of Line 3 and the value of φ to deter-mine Σf on Scale C. From Σf on Scale C, draw Line 5 through theintersection of Σh and Σw to determine Sw on Scale D.
ExampleGiven: Σlog = 25 c.u.
Σma = 8 c.u.
Σh = 18 c.u.
Σw = 80 c.u.
Σsh = 45 c.u.
φlog = 33 p.u.
φsh = 45 p.u.
Vsh = 0.2.
Find: φshcor and Sw.
Answer: First find the porosity corrected for shaliness, φshcor = 33 p.u. – (0.2 × 45 p.u.) = 24 p.u. This value is used for the φ point between Scales B and C.
Sw = 43%.
Saturation—Wireline
Capture Cross Section ToolCased Hole
continued on next page
243
244
Saturation—Wireline
Capture Cross Section ToolCased Hole SatCH-1
(former Sw-12)
2
4
100 90 80 70 60 50 40 30 20 10 0
3040
5060 70 80
90120
20
60
100
200
250 0 10 15 21
20 30 40 50 60 70 80 90 100 110 120
50 40 30 20 10 0
100 120 140 160 200 300 400
20 30 40 50 60
200 150 120 100 90 80
5
1015
2025
303540
45
0.1
0.5
Pivot point A
0.40.3
0.2
40
Σsh
Σsh (c.u.)
tsh (µs)
Σlog
ΣmaΣcorΣ (c.u.)
t (µs)
Σma (c.u.) Σf (c.u.)
Σw (c.u.)
Σh (c.u.)
Sw (%)
Formation watersalinity (ppm × 1,000)
Sw = (Σ log – Σma) – φ(Σh – Σma) – Vsh (Σsh – Σma)
φ(Σw – Σh)
φ (p.u.)
a b
A
B
C
D
Vsh
Pivot point B
1
5
3
0 5 10 15
© Schlumberger
SatOH
SatCH
PurposeThis chart is used to graphically interpret the TDT* Thermal DecayTime log. In one technique, applicable in shaly as well as cleansands, the apparent water capture cross section (Σwa) is plottedversus bound-water saturation (Swb) on a specially constructed grid todetermine the total water saturation (Swt).
DescriptionTo construct the grid, refer to the example chart on this page. Threefluid points must be located: free-water point (Σwf), hydrocarbonpoint (Σh), and a bound-water point (Σwb). The free- (or connate for-mation) water point is located on the left y-axis and can be obtainedfrom measurement of a formation water sample, from Charts Gen-12and Gen-13 if the water salinity is known, or from the TDT log ina clean water-bearing sand by using the following equation:
The hydrocarbon point is also located on the left y-axis of the grid.It can be determined from Chart Gen-14 based on the known orexpected hydrocarbon type.
The bound-water point (Swb) can be obtained from the TDT log in shale intervals also by using the Σwa equation. It is located on theright y-axis of the grid.
The distance between the free-water and hydrocarbon points islinearly divided into lines of constant water saturation drawn parallelto a straight line connecting the free-water and bound-water points.The Swt = 0% line originates from the hydrocarbon point, and the Swt = 100% line originates from the free-water point.
The value of Σwa from the equation is plotted versus Swb to giveSwt. The value of Swb can be estimated from the gamma ray or otherbound-water saturation estimator.
Once Swt and Swb are known, the water saturation of the reservoirrock exclusive of shale can be determined using
ExampleGiven: Σwf = 61 c.u. and Σh = 21 c.u. (medium-gravity oil with
modest GOR from Chart Gen-14), and Σwb = 76 c.u.(from TDT log in a shale interval and the preceding Eq. 1).
Find: Swt and Sw for Point 4.
Answer: Σwa = 54 c.u. (from Eq. 1) and Swb = 25% (from gamma ray).
Swt = 72% and Sw = 63% (from the preceding Sw
equation).
The grid can also be used to graphically determine watersaturation (Sw) in clean formations by crossplotting Σlog on the y-axis and porosity (φ) on the x-axis. The values of Σma and Sw neednot be known but must be constant over the interval studied. Theremust be some points from 100% water zones and a good variation inporosity. These water points define the Sw = 100% line; when extrap-olated, this line intersects the zero-porosity axis at Σma. The Sw = 0%line is drawn from Σma at φ = 0 p.u. to Σ = Σh at φ = 100 p.u. (or Σ = 1⁄2(Σma + Σh) at φ = 50 p.u.). The vertical distance from Sw = 0%to Sw = 100% is divided linearly to define lines of constant water saturation. The water saturation of any plotted point can thereby be determined.
Saturation—Wireline
Capture Cross Section Tool Cased Hole
0 20 40 60 80 100Swb (%)
40 44 48 52 56 60 64 68 72 76 80Gamma Ray
(gAPI)
Σwa (c.u.)
90
85
80
75
70
65
60
55
50
45
40
35
30
25
20
15
10
5
Free-waterpoint
Σwf = 61
Bound-waterpoint
Σwb = 76
100% water line
Hydrocarbonpoint
Σh = 21
86 5
4
3
2
1
7
S wt = S wb
80
70
60
50
40
30
20
0
10
90%
SS S
Swwt wb
wb=
−−1
.
ΣΣ Σ
Σwama
ma=−
+log .φ
(1)
(2)
*Mark of Schlumberger© Schlumberger
continued on next page245
246
SatCH
Saturation—Wireline
*Mark of Schlumberger© Schlumberger
Capture Cross Section ToolCased Hole SatCH-2
(former Sw-17)
φ or Swb
ΣlogorΣwa
© Schlumberger
SatCH
Saturation—Wireline
RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in. Carbon/Oxygen Ratio—Open Hole
PurposeCharts SatCH-3 through SatCH-8 are presented for illustrative purposes only. They are used to ensure that the measured near- andfar-detector carbon/oxygen (C/O) ratio data are consistent with theinterpretation model. These example charts are drawn for specificcased and open holes and tool sizes to provide trapezoids for the to determination of oil saturation (So) and oil holdup (yo).
DescriptionKnown formation and borehole data define the expected C/O ratiovalues, which are determined in water saturation and boreholeholdup values ranging from 0 to 1. All log data for formations withporosity (φ) greater than 10 p.u. should be within the trapezoidalarea bounded by the limits of the So and yo values. If data plot
consistently outside the trapezoid, the interpretation model mayrequire revision.
The rectangle within each chart is constructed from four distinctpoints determined by the intersection of the near- and far-detectorC/O ratios: WW = water/water point
WO = water/oil point
OW = oil/water point
OO = oil/oil point.
RST Reservoir Saturation Tool processing then determines the watersaturation (Sw) of the formation.
continued on next page247
248
SatCH
Saturation—Wireline
RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 6.125-in. BoreholeCarbon/Oxygen Ratio—Open Hole
φ = 30%, 6.125-in. Open Hole
Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
φ = 20%, 6.125-in. Open Hole
0.8
0.6
0.4
0.2
0
0 0.5 1.0
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
0.8
0.6
0.4
0.2
0
0 0.5 1.0
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
OO
OW
WO
WW
OO
OW
WO
OO
OW
WO
WO
OW
OO
WW
OW
OO
WO
WW
OW
OO
WO
WW
OO
OW
WO
WW
OO
OW
WO
WW
WWWW
SatCH-3(former RST-3)
*Mark of Schlumberger© Schlumberger
249
SatCH
Saturation—Wireline
RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 9.875-in. BoreholeCarbon/Oxygen Ratio—Open Hole
SatCH-4
φ = 30%, 9.875-in. Open Hole
φ = 20%, 9.875-in. Open Hole1.5
1.0
0.5
0
0 1.5
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-Band RST-D, limestoneRST-B, quartz sandstone
Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
0.5 1.0
1.5
1.0
0.5
0
0 1.5
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
0.5 1.0
OWWO
WW
WO
WW
OW
OW
OW
WO
WW
OW
OO
OO
OW
WW
WWWO
WO
WW
OO
OW
WW
OO
OW
WW
WO
*Mark of Schlumberger© Schlumberger
250
SatCH
Saturation—Wireline
RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 8.125-in. Borehole with 4.5-in. Casing at 11.6 lbm/ftCarbon/Oxygen Ratio—Cased Hole
SatCH-5(former RST-5)
φ = 30%, 6.125-in. Borehole, 4.5-in. Casing at 11.6 lbm/ft
Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
φ = 20%, 6.125-in. Borehole, 4.5-in. Casing at 11.6 lbm/ft
0.8
0.6
0.4
0.2
0
0 0.5 1.0
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
0.8
0.6
0.4
0.2
0
0 0.5 1.0
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
OO
OW
WO
WW
OW
OW
OW
WOWO
WOWW
WW
OO
OO
OO
OW
WO
WWWO
OWOO
OWWO
WW
WW
OWWO
WW
OO
OO
OO
*Mark of Schlumberger© Schlumberger
251
SatCH
Saturation—Wireline
RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 7.875-in. Borehole with 5.5-in. Casing at 17 lbm/ftCarbon/Oxygen Ratio—Cased Hole
SatCH-6
φ = 30%, 7.875-in. Borehole, 5.5-in. Casing at 17 lbm/ft
Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
φ = 20%, 7.875-in. Borehole, 5.5-in. Casing at 17 lbm/ft
0.8
0.6
0.4
0.2
0
0 0.5 1.0
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
0.8
0.6
0.4
0.2
0
0 0.5 1.0
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
WO
OO
OW
OO
OW
WO
WW
WW
OW
OO
WO
WW
WW
WO
OW
OO
OO
WWOO
OW
OW
WO
WW
WO
OO
OW
WO
WW
WWWO
OW
OO
*Mark of Schlumberger© Schlumberger
252
SatCH
Saturation—Wireline
RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 8.5-in. Borehole with 7-in. Casing at 29 lbm/ftCarbon/Oxygen Ratio—Cased Hole
SatCH-7(former RST-1)
Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
φ = 20%, 8.5-in. Borehole, 7-in. Casing at 29 lbm/ft
0.8
0.6
0.4
0.2
0
0 0.5 1.0
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
φ = 30%, 8.5-in. Borehole, 7-in. Casing at 29 lbm/ft
0.8
0.6
0.4
0.2
0
0 0.5 1.0
WO
WW
OW
OO
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
OW
OO
WO
WO
OO
OW
WW
WW
OO
OW
OO
OWWO
WW
OO
OW
WO
WW WO
WW
OW
OO
OW
OO
WW
*Mark of Schlumberger© Schlumberger
253
SatCH
Saturation—Wireline
RST* Reservoir Saturation Tool—1.6875 in. and 2.5 in. in 9.875-in. Borehole with 7-in. Casing at 29 lbm/ftCarbon/Oxygen Ratio—Cased Hole
SatCH-8(former RST-2)
φ = 30%, 9.875-in. Borehole, 7-in. Casing at 29 lbm/ft
Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
φ = 20%, 9.875-in. Borehole, 7-in. Casing at 29 lbm/ft
0.8
0.6
0.4
0.2
0
0 0.5 1.0
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
Near-detector carbon/oxygen ratio
Far-detectorcarbon/oxygen
ratio
0.8
0.6
0.4
0.2
0
0 0.5 1.0
RST-A and RST-C, limestoneRST-A, quartz sandstoneRST-B and RST-D, limestoneRST-B, quartz sandstone
OO
OWWO
WW
OO
OWWO
WW
OO
OW
WO
WW
OO
OW
WW
WO
OW
OO
WW
WO
OW
OO
WO
WW
OO
OW
WWWW
WO
OW
OO
WO
*Mark of Schlumberger© Schlumberger
254
Perm
GeneralGeneralPermeability
Permeability from Porosity and Water SaturationOpen Hole
Purpose Charts Perm-1 and Perm-2 are used to estimate the permeability ofshales, shaly sands, or other hydrocarbon-saturated intergranularrocks at irreducible water saturation (Swi).
DescriptionThe charts are based on empirical observations and are similar inform to a general expression proposed by Wyllie and Rose (1950)(see Reference 49):
Chart Perm-1 presents the results of one study for which theobserved relation was
Chart Perm-2 presents the results of another study:
The charts are valid only for zones at irreducible water saturation.Enter porosity (φ) and Swi on a chart. Their intersection defines
the intrinsic (absolute) rock permeability (k). Medium-gravity oil isassumed. If the saturating hydrocarbon is other than medium-gravityoil, a correction factor (C′) based on the fluid densities of water andhydrocarbons (ρw and ρh, respectively) and elevation above the free-water level (h) should be applied to the Swi value before it is enteredon the chart. The chart on this page provides the correction factorbased on the capillary pressure:
Charts Perm-1 and Perm-2 can be used to recognize zones at irre-ducible water saturation, for which the product φSwi from levels withinthe zone is generally constant and plots parallel to the φSwi lines.
ExampleGiven: φ = 23 p.u., Swi = 30%, gas saturation with ρh = 0.3 g/cm3
and ρw = 1.1 g/cm3, and h = 120 ft.
Find: Correction factor and k.
Answer: First, find pc to determine the correction factor if thezone of interest is not at irreducible water saturation:
Enter the correction factor chart with Swi = 30% to inter-sect the curve for pc = 40 (nearest to 42), for which thecorrection factor is 1.08. The corrected Swi value is Swi =1.08 × 30% = 32.4%.
Chart Perm-1: φS wi = 0.072% and k = 130 mD.
Chart Perm-2: φS wi = 0.072% and k = 65 mD.
ph
cw h=
−( )ρ ρ2 3.
.
kCS
Cwi
1 2 =⎛
⎝⎜⎞
⎠⎟+ ′φ
.
kSwi
1 2 2 25100=⎛
⎝⎜
⎞
⎠⎟
φ .
.
kS
Sewi
wi
1 2 2701
φ−⎛
⎝⎜⎞
⎠⎟.
ph
cw h=
−( )=
−( )=
ρ ρ2 3
120 1 1 0 3
2 342
.
. .
..
2.0
1.8
1.6
1.4
1.2
1.0
0.8 0 20 40 60 80 100
Irreducible water saturation, Swi (%)
Correction factor, C′
pc = 200
pc = 100
pc = 10pc = 0
pc = 40
pc =h(ρw – ρo)
2.3
(1)
(2)
(3)
(4)
© Schlumberger
255
Perm
General
Permeability from Porosity and Water SaturationOpen Hole
GeneralPermeability
Perm-1(former K-3)
60
50
40
30
20
10
0 0 5 10 15 20 25 30 35 40
Porosity, φ (p.u.)
Irreducible water
saturationabove
transitionzone,
Swi (%)
φSwi
0.12
0.10
0.08
0.06
0.04
0.02
0.01
5,0002,000
1,000500
200100
50
20
10
5
2
1.0
0.5
0.2
0.10.01
Permeability, k (mD)
© Schlumberger
256
Perm
General
This chart is used similarly to Chart Perm-1 for the relation
Permeability
Permeability from Porosity and Water SaturationOpen Hole Perm-2
(former K-4)
40
35
30
25
20
15
10
5
0 0 10 20 30 40 50 60 70 80 90 100
Irreducible water saturation above transition zone, Swi (%)
Porosity,φ (p.u.)
φSwi
Permeability, k (m
D)
5,000
1,000
2,000
500
200
5020
10
100
5
1
0.01
0.02
0.04
0.06
0.08
0.10
0.12
0.100.01
kS
Sewi
wi
1 2 2701
φ−⎛
⎝⎜⎞
⎠⎟.
© Schlumberger
257
Perm
PurposeThis chart is used to estimate ease of movement through a formationby a fluid.
DescriptionThe mobility-added slowness, which is the difference between theStoneley slowness and the calculated elastic Stoneley slowness, isplotted on the x-axis and the mobility of the fluid is on the y-axis. Themembrane impedance curves represent the effect that the mudcakehas on the determination of the mobility of the fluid in the formation.The membrane impedance is scaled in gigapascal per centimeter.
GeneralPermeability
Fluid Mobility Effect on Stoneley SlownessOpen Hole Perm-3
0.1
10
100
1,000 50 10 5 1
10,000
0.1 1 10 100
Membrane impedance
0 GPa/cm(no mudcake)
Fresh Mud at 600 Hz
Mobility-added slowness, S – Se (µs/ft)
Mobility(mD/cp)
© Schlumberger
General
258
Cement Bond Log—Casing Strength Interpretation—Cased Hole
PurposeThis chart is used to determine the decibel attenuation of casingfrom the measured cement bond log (CBL) amplitude and convert it to the compressive strength of bonded cement (either standard or foamed).
DescriptionThe amplitude of the first casing arrival is recorded by an acousticsignal-measuring device such as a sonic or cement bond tool. Thisamplitude value is a measure of decibel attenuation that can betranslated into a bond index (an indication of the percent of casingcement bonding) and the compressive strength (psi) of the cementat the time of logging.
Enter the chart on the y-axis with the log value of CBL amplitudeand move upward parallel to the 45° lines to intersect the appropri-ate casing size. At that point, move horizontally right to the attenua-tion scale on the right-hand y-axis. From this point, draw a linethrough the appropriate casing thickness value to intersect the com-pressive strength scale. The casing wall thickness is calculated bysubtracting the nominal inside diameter (ID) from the outsidediameter (OD) listed on the table for threaded nonupset casing and dividing the difference by 2.
ExampleGiven: Log amplitude reading = 3.5 mV in zone of interest
and 1.0 mV in a well-bonded section (usually the lowestmillivolt value on the log), casing size = 7 in. at 29 lbm/ft, casing thickness = 0.41 in., and neat cement(not foamed).
Find: Compressive strength and bond index of the cement atthe time of logging.
Answer: Enter the 3.5-mV reading on the left y-axis of Chart Cem-1 and proceed to the 7-in. casing line.
Move horizontally to intersect the right-hand y-axis at 8.9 dB/ft.
Determine the casing thickness as (7 – 6.184)/2 = 0.816/2= 0.41 in. Draw a line from 8.9 dB/ft through the 0.41-in.casing thickness point to the compressive strength scale.
Cement compressive strength = 2,100 psi.
To find the bond index, determine the decibel attenuation of the lowest recorded log value by entering 1.0 mV on the left-hand y-axisand proceeding to the 7-in. casing line. Move horizontally to intersectthe right-hand y-axis at 12.3 dB/ft.
Divide the precisely determined decibel attenuation for the CBLamplitude in the zone of interest by this value for the lowest millivoltvalue: 8.9/12.3 = 72% bond index.
A 72% bond index means that 72% of the casing is bonded. This is not a well-bonded zone because a value of 80% bonding over a 10-ftinterval is historically considered well bonded. Although the loggingscale is a linear millivolts scale, the decibel attenuation scale is loga-rithmic. The millivolts log scale for the CBL value cannot rescaled in percent of bonding. If it were, the apparent percent bondingwould be 65% because most bond log scales are from 0 to 100 mVreading from left to right, over 10 divisions of track 1, or conversely100% to 0% cement bonding for 0 mV = 100% bonding and 100 mV = 0% bonding.
Cem
Cement Evaluation—Wireline
OD Weight Nominal Drift(in.) per ft† ID Diameter‡
(lbm) (in.) (in.)
10 33.00 9.384 9.228
103⁄4 32.75 10.192 10.03640.00 10.054 9.89840.50 10.050 9.89445.00 9.960 9.80445.50 9.950 9.79448.00 9.902 9.74651.00 9.850 9.69454.00 9.784 9.62855.50 9.760 9.604
113⁄4 38.00 11.150 10.99442.00 11.084 10.92847.00 11.000 10.84454.00 10.880 10.72460.00 10.772 10.616
12 40.00 11.384 11.228
13 40.00 12.438 12.282
133⁄8 48.00 12.715 12.559
16 55.00 15.375 15.187
185⁄8 78.00 17.855 17.667
20 90.00 19.190 19.002
211⁄2 92.50 20.710 20.522103.00 20.610 20.422114.00 20.510 20.322
241⁄2 100.50 23.750 23.562113.00 23.650 23.462
† Weight per foot in pounds is given for plain pipe (no threads or coupling).
‡ Drift diameter is the guaranteed minimum inside diameter of any part of the casing. Use drift diameter to determine the largest-diameter equipment that can be safely run inside the casing. Use inside diameter for volume capacity calculations.
259
Cem
Cement Evaluation—Wireline
Cement Bond Log—Casing StrengthInterpretation—Cased Hole
OD Weight Nominal Drift(in.) per ft† ID Diameter‡
(lbm) (in.) (in.)
4 11.60 3.428 3.303
41⁄2 9.50 4.090 3.96511.60 4.000 3.87513.50 3.920 3.795
43⁄4 16.00 4.082 3.957
5 11.50 4.560 4.43513.00 4.494 4.36915.00 4.408 4.28317.70 4.300 4.17518.00 4.276 4.15121.00 4.154 4.029
51⁄2 13.00 5.044 4.91914.00 5.012 4.88715.00 4.974 4.84915.50 4.950 4.82517.00 4.892 4.76720.00 4.778 4.65323.00 4.670 4.545
53⁄4 14.00 5.290 5.16517.00 5.190 5.06519.50 5.090 4.96522.50 4.990 4.865
6 15.00 5.524 5.39916.00 5.500 5.37518.00 5.424 5.29920.00 5.352 5.22723.00 5.240 5.115
65⁄8 17.00 6.135 6.01020.00 6.049 5.92422.00 5.989 5.86424.00 5.921 5.79626.00 5.855 5.73026.80 5.837 5.71228.00 5.791 5.66629.00 5.761 5.63632.00 5.675 5.550
continued on next page
OD Weight Nominal Drift(in.) per ft† ID Diameter‡
(lbm) (in.) (in.)
7 17.00 6.538 6.41320.00 6.456 6.33122.00 6.398 6.27323.00 6.366 6.24124.00 6.336 6.21126.00 6.276 6.15128.00 6.214 6.08929.00 6.184 6.05930.00 6.154 6.02932.00 6.094 5.96935.00 6.004 5.87938.00 5.920 5.79540.00 5.836 5.711
75⁄8 20.00 7.125 7.00024.00 7.025 6.90026.40 6.969 6.84429.70 6.875 6.75033.70 6.765 6.64039.00 6.625 6.500
85⁄8 24.00 8.097 7.97228.00 8.017 7.89232.00 7.921 7.79636.00 7.825 7.70038.00 7.775 7.65040.00 7.725 7.60043.00 7.651 7.52644.00 7.625 7.50049.00 7.511 7.386
9 34.00 8.290 8.16538.00 8.196 8.07140.00 8.150 8.02545.00 8.032 7.90755.00 7.812 7.687
95⁄8 29.30 9.063 8.90732.30 9.001 8.84536.00 8.921 8.76540.00 8.835 8.67943.50 8.755 8.59947.00 8.681 8.52553.50 8.535 8.379
Threaded Nonupset Casing
260
Cem
General
Cement Bond Log—Casing StrengthInterpretation—Cased Hole Cem-1
(former M-1)
Cement Evaluation—Wireline
Casing size (mm) Centered tool only, 3-ft [0.914-m] spacing
Casing size (in.)
(dB/ft)
Casing thickness(mm) (in.)
CBL amplitude(mV)
Attenuation(dB/m)
115
41/2 7
51/2 75/8
103/4
133/8
15
10
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
4
8
12
16
20
24
28
32
36
40
44
48
52
56
70
50
40
30
20
15
109876
5
4
3
2
1
0.5
0.2
8
7
6
5 0.2
0.3
0.4
0.5
0.6
7 in. at 29 lbm
140194
176273
340
Compressive strength(psi)
(mPa)
Standardcement
Foamed cement
6
5
4
3
2
1
1,000
800
500
300
200
100
30
25
20
15
10
5
3
2
1
0.5
0.3
4,000
3,000
2,000
1,000
500
250
100
50
© Schlumberger
Appendix A
261
Linear Grid
262
Appendix AAppendix A
9
8
7
6
5
4
3
2
1
9
8
7
6
5
4
3
2
1
Log-Linear Grid
Appendix A
263
Appendix A
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.60
0.70
0.80
0.901.0
1.2
1.41.61.82.0
2.5
3.0
4.05.06.0
8.010
1520304050100200
∞
5,000
4,000
3,000
2,500
2,000
1,500
1,000
500
400
300
200
150
100
50
25
10
0
Resistivity scale may bemultiplied by 10 for usein a higher range
Conductivity (mmho/m)
Resistivity(ohm-m)
ρb
φ
FR
For FR = 0.62φ2.15
Water Saturation Grid for Resistivity Versus Porosity
264
Appendix AAppendix A
2
2.5
3
3.5
4
4.5
5
6
7
8
910
12
14
16
20
2530
40
50
100
200
5001,0002,000
∞
500
400
300
250
200
150
100
50
40
30
20
10
5
0
Resistivity scale may bemultiplied by 10 for usein a higher range
Conductivity (mmho/m)
Resistivity(ohm-m)
ρb
φ
FR
For FR =1φ2
Water Saturation Grid for Resistivity Versus Porosity
Appendix B Logging Tool Response in Sedimentary Minerals
Name Formula ρlog φSNP φCNL φAPS† ∆tc ∆ts Pe U ε tp Gamma Ray Σ(g/cm3) (p.u.) (p.u.) (p.u.) (µs/ft) (µs/ft) (farad/m) (ns/m) (gAPI Units) (c.u.)
Silicates
Quartz SiO2 2.64 –1 –2 –1 56.0 88.0 1.8 4.8 4.65 7.2 4.3
β-cristobalite SiO2 2.15 –2 –3 1.8 3.9 3.5
Opal (3.5% H2O) SiO2 (H2O)0.1209 2.13 4 2 58 1.8 3.7 5.0
Garnet‡ Fe3Al2(SiO4)3 4.31 3 7 11 48 45
Hornblende‡Ca2NaMg2Fe2
AlSi8O22(O,OH)23.20 4 8 43.8 81.5 6.0 19 18
Tourmaline NaMg3Al6B3Si6O2(OH)4 3.02 16 22 2.1 6.5 7450
Zircon ZrSiO4 4.50 –1 –3 69 311 6.9
Carbonates
Calcite CaCO3 2.71 0 0 0 49.0 88.4 5.1 13.8 7.5 9.1 7.1
Dolomite CaCO3MgCO3 2.85 2 1 1 44.0 72 3.1 9.0 6.8 8.7 4.7
Ankerite Ca(Mg,Fe)(CO3)2 2.86 0 1 9.3 27 22
Siderite FeCO3 3.89 5 12 3 47 15 57 6.8–7.5 8.8–9.1 52
Oxidates
Hematite Fe2O3 5.18 4 11 42.9 79.3 21 111 101
Magnetite Fe3O4 5.08 3 9 73 22 113 103
Goethite FeO(OH) 4.34 50+ 60+ 19 83 85
Limonite‡ FeO(OH)(H2O)2.05 3.59 50+ 60+ 56.9 102.6 13 47 9.9–10.9 10.5–11.0 71
Gibbsite Al(OH)3 2.49 50+ 60+ 1.1 23
Phosphates
Hydroxyapatite Ca5(PO4)3OH 3.17 5 8 42 5.8 18 9.6
Chlorapatite Ca5(PO4)3Cl 3.18 –1 –1 42 6.1 19 130
Fluorapatite Ca5(PO4)3F 3.21 –1 –2 42 5.8 19 8.5
Carbonapatite (Ca5(PO4)3)2CO3H2O 3.13 5 8 5.6 17 9.1
Feldspars—Alkali‡
Orthoclase KAlSi3O8 2.52 –2 –3 69 2.9 7.2 4.4–6.0 7.0–8.2 ~220 16
Anorthoclase KAlSi3O8 2.59 –2 –2 2.9 7.4 4.4–6.0 7.0–8.2 ~220 16
Microcline KAlSi3O8 2.53 –2 –3 2.9 7.2 4.4–6.0 7.0–8.2 ~220 16
Feldspars—Plagioclase‡
Albite NaAlSi3O8 2.59 –1 –2 –2 49 85 1.7 4.4 4.4–6.0 7.0–8.2 7.5
Anorthite CaAl2Si2O8 2.74 –1 –2 45 3.1 8.6 4.4–6.0 7.0–8.2 7.2
Micas‡
Muscovite KAl2(Si3AlO10)(OH)2 2.82 12 ~20 ~13 49 149 2.4 6.7 6.2–7.9 8.3–9.4 ~270 17
GlauconiteK0.7(Mg,Fe2,Al)
2.86 ~38 ~15 4.8 14 21(Si4,Al10)O2(OH)
Biotite K(Mg,Fe)3(AlSi3O10)(OH)2 ~2.99 ~11 ~21 ~11 50.8 224 6.3 19 4.8–6.0 7.2–8.1 ~275 30
Phlogopite KMg3(AlSi3O10)(OH)2 50 207 33
†APS* Accelerator Porosity Sonde porosity derived from near-to-array ratio (APLC)‡Mean value, which may vary for individual samples
For more information, see Reference 41.
265
266
Appendix B Logging Tool Response in Sedimentary Minerals
Name Formula ρlog φSNP φCNL φAPS† ∆tc ∆ts Pe U ε tp Gamma Ray Σ(g/cm3) (p.u.) (p.u.) (p.u.) (µs/ft) (µs/ft) (farad/m) (ns/m) (gAPI Units) (c.u.)
Clays‡
Kaolinite Al4Si4O10(OH)8 2.41 34 ~37 ~34 1.8 4.4 ~5.8 ~8.0 80–130 14
Chlorite(Mg,Fe,Al)6(Si,Al)4
2.76 37 ~52 ~35 6.3 17 ~5.8 ~8.0 180–250 25O10(OH)8
IlliteK1–1.5Al4(Si7–6.5,Al1–1.5)
2.52 20 ~30 ~17 3.5 8.7 ~5.8 ~8.0 250–300 18O20(OH)4
Montmorillonite(Ca,Na)7(Al,Mg,Fe)4
2.12 ~60 ~60 2.0 4.0 ~5.8 ~8.0 150–200 14(Si,Al)8O20(OH)4(H2O)n
Evaporites
Halite NaCl 2.04 –2 –3 21 67.0 120 4.7 9.5 5.6–6.3 7.9–8.4 754
Anhydrite CaSO4 2.98 –1 –2 2 50 5.1 15 6.3 8.4 12
Gypsum CaSO4(H2O)2 2.35 50+ 60+ 60 52 4.0 9.4 4.1 6.8 19
Trona Na2CO3NaHCO3H2O 2.08 24 35 65 0.71 1.5 16
Tachhydrite CaCl2(MgCl2)2(H2O)12 1.66 50+ 60+ 92 3.8 6.4 406
Sylvite KCl 1.86 –2 –3 8.5 16 4.6–4.8 7.2–7.3 500+ 565
Carnalite KClMgCl2(H2O)6 1.57 41 60+ 4.1 6.4 ~220 369
Langbeinite K2SO4(MgSO4)2 2.82 –1 –2 3.6 10 ~290 24
PolyhaliteK2SO4Mg
2.79 14 25 4.3 12 ~200 24SO4(CaSO4)2(H2O)2
Kainite MgSO4KCl(H2O)3 2.12 40 60+ 3.5 7.4 ~245 195
Kieserite MgSO4(H2O) 2.59 38 43 1.8 4.7 14
Epsomite MgSO4(H2O)7 1.71 50+ 60+ 1.2 2.0 21
Bischofite MgCl2(H2O)6 1.54 50+ 60+ 100 2.6 4.0 323
Barite BaSO4 4.09 –1 –2 267 1090 6.8
Celestite SrSO4 3.79 –1 –1 55 209 7.9
Sulfides
Pyrite FeS2 4.99 –2 –3 39.2 62.1 17 85 90
Marcasite FeS2 4.87 –2 –3 17 83 88
Pyrrhotite Fe7S8 4.53 –2 –3 21 93 94
Sphalerite ZnS 3.85 –3 –3 36 138 7.8–8.1 9.3–9.5 25
Chalcopyrite CuFeS2 4.07 –2 –3 27 109 102
Galena PbS 6.39 –3 –3 1,630 10,400 13
Sulfur S 2.02 –2 –3 122 5.4 11 20
Coals
Anthracite CH0.358N0.009O0.022 1.47 37 38 105 0.16 0.23 8.7
Bituminous CH0.793N0.015O0.078 1.24 50+ 60+ 120 0.17 0.21 14
Lignite CH0.849N0.015O0.211 1.19 47 52 160 0.20 0.24 13
†APS* Accelerator Porosity Sonde porosity derived from near-to-array ratio (APLC)‡Mean value, which may vary for individual samples
For more information, see Reference 41.
Appendix C
267
Appendix C Acoustic Characteristics of Common Formations and Fluids
Nonporous Solids
Material ∆t Sound Velocity Acoustic Impedance(µs/ft) (ft/s) (m/s) (MRayl)
Casing 57.0 17,500 5,334 41.60
Dolomite 43.5 23,000 7,010 20.19
Anhydrite 50.0 20,000 6,096 18.17
Limestone 47.6 21,000 6,400 17.34
Calcite 49.7 20,100 6,126 16.60
Quartz 52.9 18,900 5,760 15.21
Gypsum 52.6 19,000 5,791 13.61
Halite 66.6 15,000 4,572 9.33
Water-Saturated Porous Rock
Material Porosity ∆t Sound Velocity Acoustic Impedance(%) (µs/ft) (ft/s) (m/s) (MRayl)
Dolomite 5–20 50.0–66.6 20,000–15,000 6,096–4,572 16.95–11.52
Limestone 5–20 54.0–76.9 18,500–13,000 5,639–3,962 14.83–9.43
Sandstone 5–20 62.5–86.9 16,000–11,500 4,877–3,505 12.58–8.20
Sand 20–35 86.9–111.1 11,500–9,000 3,505–2,743 8.20–6.0
Shale 58.8–143.0 17,000–7,000 5,181–2,133 12.0–4.3
Nonporous Solids
Material ∆t Sound Velocity Acoustic Impedance(µs/ft) (ft/s) (m/s) (MRayl)
Water 208 4,800 1,463 1.46
Water + 10% NaCl 192.3 5,200 1,585 1.66
Water + 20% NaCl 181.8 5,500 1,676 1.84
Seawater 199 5,020 1,531 1.57
Kerosene 230 4,340 1,324 1.07
Air at 15 psi, 32°F [0°C] 920 1,088 331 0.0004
Air at 3,000 psi, 212°F [100°C] 780 1,280 390 0.1
268
Appendix D Conversions
Length
Multiply Centimeters Feet Inches Kilometers Nautical Meters Mils Miles Millimeters YardsNumber Miles
oftoObtain by
Centimeters 1 30.48 2.540 105 1.853 × 105 100 2.540 × 10–3 1.609 × 105 0.1 91.44
Feet 3.281 × 10–2 1 8.333 × 10–2 3281 6080.27 3.281 8.333 ×10–5 5280 3.281 × 10–3 3
Inches 0.3937 12 1 3.937 × 104 7.296 × 104 39.37 0.001 6.336 ×104 3.937 × 10–2 36
Kilometers 10–5 3.048 × 10–4 2.540 × 10–5 1 1.853 0.001 2.540 × 10–8 1.609 10–6 9.144 × 10–4
Nautical miles 1.645 × 10–4 0.5396 1 5.396 ×10–4 0.8684 4.934 ×10–4
Meters 0.01 0.3048 2.540 × 10–2 1000 1853 1 1609 0.001 0.9144
Mils 393.7 1.2 × 104 1000 3.937 × 107 3.937 × 104 1 39.37 3.6 × 104
Miles 6.214 × 10–6 1.894 × 10–4 1.578 × 10–5 0.6214 1.1516 6.214 × 10–4 1 6.214 × 10–7 5.682 × 10–4
Millimeters 10 304.8 25.40 105 1000 2.540 × 10–2 1 914.4
Yards 1.094 × 10–2 0.3333 2.778 × 10–2 1094 2027 1.094 2.778 × 10–5 1760 1.094 × 10–3 1
Area
Multiply Acres Circular Square Square Square Square Square Square Square SquareNumber Mils Centimeters Feet Inches Kilometers Meters Miles Millimeters Yards
oftoObtain by
Acres 1 2.296 × 10–5 247.1 2.471 × 10–4 640 2.066 × 10–4
Circular mils 1 1.973 × 105 1.833 × 108 1.273 × 106 1.973 ×109 1973
Squarecentimeters 5.067 × 10–6 1 929.0 6.452 1010 104 2.590 × 1010 0.01 8361
Square feet 4.356 × 104 1.076 × 10–3 1 6.944 × 10–3 1.076 × 107 10.76 2.788 × 107 1.076 × 10–5 9
Square inches 6,272,640 7.854 × 10–7 0.1550 144 1 1.550 × 109 1550 4.015 × 109 1.550 × 10–3 1296
Squarekilometers 4.047 × 10–3 10–10 9.290 × 10–8 6.452 × 10–10 1 10–6 2.590 10–12 8.361 × 10–7
Square meters 4047 0.0001 9.290 × 10–2 6.452 × 10–4 106 1 2.590 × 106 10–6 0.8361
Square miles 1.562 × 10–3 3.861 × 10–11 3.587 × 10–8 0.3861 3.861 × 10–7 1 3.861 × 10–13 3.228 × 10–7
Squaremillimeters 5.067 × 10–4 100 9.290 × 104 645.2 1012 106 1 8.361 × 105
Square yards 4840 1.196 × 10–4 0.1111 7.716 × 10–4 1.196 × 106 1.196 3.098 × 106 1.196 × 10–6 1
269
Appendix D Conversions
Volume
Multiply Bushels Cubic Cubic Cubic Cubic Cubic Gallons Liters Pints QuartsNumber (Dry) Centimeters Feet Inches Meters Yards (Liquid) (Liquid) (Liquid)
oftoObtain by
Bushels (dry) 1 0.8036 4.651 × 10–4 28.38 2.838 × 10–2
Cubiccentimeters 3.524 × 104 1 2.832 × 104 16.39 106 7.646 × 105 3785 1000 473.2 946.4
Cubic feet 1.2445 3.531 × 10–5 1 5.787 × 10–4 35.31 27 0.1337 3.531 × 10–2 1.671 × 10–2 3.342 × 10–2
Cubic inches 2150.4 6.102 × 10–2 1728 1 6.102 × 104 46,656 231 61.02 28.87 57.75
Cubic meters 3.524 × 10–2 10–6 2.832 × 10–2 1.639 × 10–5 1 0.7646 3.785 × 10–3 0.001 4.732 × 10–4 9.464 × 10–4
Cubic yards 1.308 × 10–6 3.704 × 10–2 2.143 × 10–5 1.308 1 4.951 × 10–3 1.308 × 10–3 6.189 × 10–4 1.238 × 10–3
Gallons(liquid) 2.642 × 10–4 7.481 4.329 × 10–3 264.2 202.0 1 0.2642 0.125 0.25
Liters 35.24 0.001 28.32 1.639 × 10–2 1000 764.6 3.785 1 0.4732 0.9464
Pints (liquid) 2.113 × 10–3 59.84 3.463 × 10–2 2113 1616 8 2.113 1 2
Quarts (liquid) 1.057 × 10–3 29.92 1.732 × 10–2 1057 807.9 4 1.057 0.5 1
Mass and Weight
Multiply Grains Grams Kilograms Milligrams Ounces† Pounds† Tons Tons TonsNumber (Long) (Metric) (Short)
oftoObtain by
Grains 1 15.43 1.543 × 104 1.543 × 10–2 437.5 7000
Grams 6.481 × 10–2 1 1000 0.001 28.35 453.6 1.016 × 106 106 9.072 × 105
Kilograms 6.481 × 10–5 0.001 1 10–6 2.835 × 10–2 0.4536 1016 1000 907.2
Milligrams 64.81 1000 106 1 2.835 × 104 4.536 × 105 1.016 × 109 109 9.072 × 108
Ounces† 2.286 × 10–3 3.527 × 10–2 35.27 3.527 × 10–5 1 16 3.584 × 104 3.527 × 104 3.2 × 104
Pounds† 1.429 × 10–4 2.205 × 10–3 2.205 2.205 × 10–6 6.250 × 10–2 1 2240 2205 2000
Tons (long) 9.842 × 10–7 9.842 × 10–4 9.842 × 10–10 2.790 × 10–5 4.464 × 10–4 1 0.9842 0.8929
Tons (metric) 10–6 0.001 10–9 2.835 × 10–5 4.536 × 10–4 1.016 1 0.9072
Tons (short) 1.102 × 10–6 1.102 × 10–3 1.102 × 10–9 3.125 × 10–5 0.0005 1.120 1.102 1
†Avoirdupois pounds and ounces
270
Appendix D Conversions
Density or Mass per Unit Volume
Multiply Grams per Kilograms Pounds per Pounds per Pounds perNumber Cubic per Cubic Foot Cubic Inch Gallon
of Centimeter Cubic MetertoObtain by
Grams per cubic centimeter 1 0.001 1.602 × 10–2 27.68 0.1198
Kilograms per cubic meter 1000 1 16.02 2.768 × 104 119.8
Pounds per cubic foot 62.43 6.243 × 10–2 1 1728 7.479
Pounds per cubic inch 3.613 × 10–2 3.613 × 10–5 5.787 × 10–4 1 4.329 × 10–3
Pounds per gallon 8.347 8.3 × 10–3 13.37 × 10–2 231.0 1
Pressure or Force per Unit Area
Multiply Atmospheres† Bayres or Centimeters Inches Inches Kilograms Pounds Pounds Tons (short) PascalsNumber Dynes per of Mercury of Mercury of Water per per per per
of Square at 0°C§ at 0°C§ at 4°C Square Square Foot Square Square Footto Centimeter‡ Meter†† Inch‡‡
Obtain by
Atmospheres† 1 9.869 × 10–7 1.316 × 10–2 3.342 × 10–2 2.458 × 10–3 9.678 × 10–5 4.725 × 10–4 6.804 × 10–2 0.9450 9.869 × 10–6
Bayres or dynesper square 1.013 × 106 1 1.333 × 104 3.386 × 104 2.491 × 10–3 98.07 478.8 6.895 × 104 9.576 × 105 10centimeter‡
Centimetersof mercury 76.00 7.501 × 10–5 1 2.540 0.1868 7.356 × 10–3 3.591 × 10–2 5.171 71.83 7.501 × 10–4
at 0°C§
Inchesof mercury 29.92 2.953 × 10–5 0.3937 1 7.355 × 10–2 2.896 × 10–3 1.414 × 10–2 2.036 28.28 2.953 × 10–4
at 0°C§
Inches of 406.8 4.015 × 10–4 5.354 13.60 1 3.937 × 10–2 0.1922 27.68 384.5 4.015 × 10–3
water at 4°C
Kilogramsper square 1.033 × 104 1.020 × 10–2 136.0 345.3 25.40 1 4.882 703.1 9765 0.1020meter††
Poundsper square 2117 2.089 × 10–3 27.85 70.73 5.204 0.2048 1 144 2000 2.089 × 10–2
foot
Pounds per 14.70 1.450 × 10–5 0.1934 0.4912 3.613 × 10–2 1.422 × 10–3 6.944 × 10–3 1 13.89 1.450 × 10–4
square inch‡‡
Tons (short) per 1.058 1.044 × 10–5 1.392 × 10–2 3.536 × 10–2 2.601 × 10–3 1.024 × 10–4 0.0005 0.072 1 1.044 × 10–5
square foot
Pascals 1.013 × 105 10–1 1.333 × 103 3.386 × 103 2.491 × 10–4 9.807 47.88 6.895 × 103 9.576 × 104 1
† One atmosphere (standard) = 76 cm of mercury at 0°C‡ Bar§ To convert height h of a column of mercury at t °C to the equivalent height h0 at 0°C, use h0 = h 1 – [(m – l) t / 1 + mt], where m = 0.0001818 and l = 18.4 × 10–6 if the
scale is engraved on brass; l = 8.5 × 10–6 if on glass. This assumes the scale is correct at 0°C; for other cases (any liquid) see International Critical Tables, Vol. 1, 68.†† 1 gram per square centimeter = 10 kilograms per square meter‡‡ psi = MPa × 145.038
psi/ft = 0.433 × g/cm3 = lbf/ft3/144 = lbf/gal/19.27
Temperature
°F 1.8°C + 32
°C 5⁄9 (°F – 32)
°R °F + 459.69
K °C + 273.16
Appendix E Symbols
Traditional Standard Standard Description Customary Unit or Relation StandardSymbol SPE Computer Reserve
and Symbol† Symbol‡
SPWLA†
a a ACT electrochemical activity equivalents/liter, moles/liter
a KR COER coefficient in FR – φ relation FR = KR/φm MR, a, C
A A AWT atomic weight amu
C C ECN conductivity (electrical logging) millimho per meter (mmho/m) σ
Cp Bcp CORCP sonic compaction correction factor φSVcor = BcpφSV Ccp
D D DPH depth ft, m y, H
d d DIA diameter in. D
E E EMF electromotive force mV V
F FR FACHR formation resistivity factor FR = KR/φm
G G GMF geometrical factor (multiplier) fG
H IH HYX hydrogen index iH
h h THK bed thickness, individual ft, m, in. d, e
I I –X index i
FFI IFf FFX free fluid index iFf
SI Isl SLX silt index Islt, isl, islt
Iφ PRX porosity index iφ
SPI Iφ2 PRXSE secondary porosity index iφ2
J Gp GMFP pseudogeometrical factor fGp
K Kc COEC electrochemical SP coefficient Ec = Kclog(aw/amf) Mc, Kec
k k PRM permeability, absolute (fluid flow) mD K
L L LTH length, path length ft, m, in. s, l
M M SAD slope, sonic interval transit time versus M = [(τf – τLOG)/(ρb – ρf)] × 0.01 mθDdensity × 0.01, in M–N plot
m m MXP porosity (cementation) exponent FR = KR/φm
N N SND slope, neutron porosity versus N = (φNf – φN)/(ρb – ρf) mφNDdensity, in M-N Plot
n n SXP saturation exponent Swn = FRRw/Rt
P C CNC salinity g/g, ppm c, n
p p PRS pressure psi, kg/cm2§, atm P
Pc Pc PRSCP capillary pressure psi, kg/cm2§, atm Pc, pc
Pe photoelectric cross section† SPE Letter and Computer Symbols Standard (1986).‡ Used only if conflict arises between standard symbols used in the same paper§ The unit of kilograms per square centimeter to be replaced in use by the SI metric unit of the pascal
†† “DEL” in the operator field and “RAD” in the main-quantity field‡‡ Suggested computer symbol
271
Appendix E Symbols
272
Traditional Standard Standard Description Customary Unit or Relation StandardSymbol SPE Computer Reserve
and Symbol† Symbol‡
SPWLA†
Qv shaliness (CEC per mL water) meq/mL
q fφ shd FIMSHD dispersed-shale volume fraction of φ imfshd, qintermatrix porosity
R R RES resistivity (electrical) ohm-m ρ, r
r r RAD radial distance from hole axis in. R
S S SAT saturation fraction or percent ρ, sof pore volume
T T TEM temperature °F, °C, K θ
BHT, Tbh Tbh TEMBH bottomhole temperature °F, °C, K θBH
FT, Tfm Tf TEMF formation temperature °F, °C, K
t t TIM time µs, s, min t
t t TAC interval transit time ∆t
U volumetric cross section barns/cm3
v v VAC velocity (acoustic) ft /s, m/s V, u
V V VOL volume cm3, ft3, etc. v
V V VLF volume fraction fv, Fv
Z Z ANM atomic number
α αSP REDSP SP reduction factor
γ γ SPG specific gravity (ρ/ρw or ρg/ρair) s, Fs
φ φ POR porosity fraction or percentage f, εof bulk volume, p.u.
φ1 PORPR primary porosity fraction or percentage f1, e1of bulk volume, p.u.
φ2 PORSE secondary porosity fraction or percentage f2, e2of bulk volume, p.u.
φig PORIG intergranular porosity φig = (Vb – Vgr)/Vb fig, εig
φz, φim φim PORIM intermatrix porosity φim = (Vb – Vma)/Vb fim, εim
∆r ∆r DELRAD†† radial distance (increment) in. ∆R
∆t t TAC sonic interval transit time µs/ft ∆t
∆φNex DELPORNX‡‡ excavation effect p.u.
λ Kani COEANI coefficient of anisotropy Mani
ρ ρ DEN density g/cm3 D
Σ Σ XST neutron capture cross section c.u., cm–1 SXSTMAC macroscopic
τ τdN TIMDN thermal neutron decay time µs tdn† SPE Letter and Computer Symbols Standard (1986).‡ Used only if conflict arises between standard symbols used in the same paper§ The unit of kilograms per square centimeter is to be replaced in use by the SI metric unit of the pascal.
†† “DEL” in the operator field and “RAD” in the main-quantity field‡‡ Suggested computer symbol
Appendix E
273
Appendix F Subscripts
Traditional Standard Standard Explanation Example StandardSubscript SPE Computer Reserve
and Subscript† Subscript‡
SPWLA†
a LOG L apparent from log reading RLOG, RLL log(or use tool description subscript)
a a A apparent (general) Ra ap
abs cap C absorption, capture Σcap
anh anh AH anhydrite
b b B bulk ρb B, t
bh bh BH bottomhole Tbh w, BH
clay cl CL clay Vcl cla
cor, c cor COR corrected tcor
c c C electrochemical Ec ec
cp cp CP compaction Bcp
D D D density log d
dis shd SHD dispersed shale Vshd
dol dol DL dolomite tdol
e, eq eq EV equivalent Rweq, Rmfeq EV
f, fluid f F fluid ρf fl
fm f F formation (rock) Tf fm
g, gas g G gas Sg G
gr GR grain ρgr
gxo gxo GXO gas in flushed zone Sgxo GXO
gyp gyp GY gypsum ρgyp
h h H hole dh H
h h H hydrocarbon ρh H
hr hr HR residual hydrocarbon Shr
i i I invaded zone (inner boundary) di I
ig ig IG intergranular (incl. disp. and str. shale) φ ig
im, z im IM intermatrix (incl. disp. shale) φ im
int int I intrinsic (as opposed to log value) Σ int
irr i IR irreducible Swi ir, i
J j J liquid junction Ej ι
k k K electrokinetic Ek ek
l L log tpl log
lam l LAM lamination, laminated Vshl L
lim lim LM limiting value φ lim
liq L L liquid ρL l† SPE Letter and Computer Symbols Standard (1986).‡ Used only if conflict arises between standard symbols used in the same paper
Appendix E
274
Appendix F Subscripts
Traditional Standard Standard Explanation Example StandardSubscript SPE Computer Reserve
and Subscript† Subscript‡
SPWLA†
log LOG L log values tLOG log
ls ls LS limestone t ls lst
m m M mud Rm
max max MX maximum φmax
ma ma MA matrix tma
mc mc MC mudcake Rmc
mf mf MF mud filtrate Rmf
mfa mfa MFA mud filtrate, apparent Rmfa
min min MN minimum value
ni noninvaded zone Rni
o o O oil (except with resistivity) So N
or or OR residual oil Sor
o, 0 (zero) 0 (zero) ZR 100-percent water saturated F0 zr
p propagation tpw
PSP pSP PSP pseudostatic SP EpSP
pri 1 (one) PR primary φ1 p, pri
r r R relative kr o, krw R
r r R residual Sor, Shr R
s s S adjacent (surrounding) formation Rs
sd sd SD sand sa
ss ss SS sandstone sst
sec 2 SE secondary φ2 s, sec
sh sh SH shale Vsh sha
silt sl SL silt Isl slt
SP SP SP spontaneous potential ESP sp
SSP SSP SSP static spontaneous potential ESSP
str sh st SH ST structural shale Vshst s
t, ni t T true (as opposed to apparent) Rt tr
T t T total Ct T
w w W water, formation water Sw W
wa wa WA formation water, apparent Rwa Wap
wf wf WF well flowing conditions pwf f
ws ws WS well static conditions pws s
xo xo XO flushed zone Rxo
z, im im IM intermatrix φ im† SPE Letter and Computer Symbols Standard (1986).‡ Used only if conflict arises between standard symbols used in the same paper
Appendix E
275
Appendix F Subscripts
Traditional Standard Standard Explanation Example StandardSubscript SPE Computer Reserve
and Subscript† Subscript‡
SPWLA†
0 (zero) 0 (zero) ZR 100 percent water saturated R0 zr
AD RAD from CDR attenuation deep RAD
D D D from density log φD d
GG GG from gamma-gamma log φGG gg
IL I I from induction log RI i
ILD ID ID from deep induction log RID id
ILM IM IM from medium induction log RIM im
LL LL (also LL3, LL from laterolog RLL ll
LL8, etc.) (also LL3, LL7, LL8, LLD, LLS)
N N N from normal resistivity log RN n
N N N from neutron log φN n
PS RPS from CDR phase-shift shallow RPS
16", 16"N from 16-in. normal Log R16"
1" × 1" from 1-in. by 1-in. microinverse (MI) R1" × 1"
2" from 2-in. micronormal (MN) R2"† SPE Letter and Computer Symbols Standard (1986).‡ Used only if conflict arises between standard symbols used in the same paper
Appendix F
276
Appendix G Unit Abbreviations
These unit abbreviations, which are based on those adopted by theSociety of Petroleum Engineers (SPE), are appropriate for most publi-cations. However, an accepted industry standard may be used instead.For instance, in the drilling field, ppg may be more common thanlbm/gal when referring to pounds per gallon.
In some instances, two abbreviations are given: customary andmetric. When using the International System of Units (SI), or metric,abbreviations, use the one designated for metric (e.g., m3/h instead ofm3/hr). The use of SI prefix symbols and prefix names with customaryunit abbreviations and names, although common, is not preferred(e.g., 1,000 lbf instead of klbf).
Unit abbreviations are followed by a period only when the abbrevia-tion forms a word (for example, in. for inch).
acre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spell out
acre-foot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . acre-ft
ampere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A
ampere-hour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-hr
angstrom unit (10–8 cm). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A
atmosphere . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . atm
atomic mass unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . amu
barrel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . bbl
barrels of fluid per day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BFPD
barrels of liquid per day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BLPD
barrels of oil per day. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BOPD
barrels of water per day. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BWPD
barrels per day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B/D
barrels per minute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . bbl/min
billion cubic feet (billion = 109) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bcf
billion cubic feet per day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bcf/D
billion standard cubic feet per day . . . . . . . . . . . Use Bcf/D instead of Bscf/D (see “standard cubic foot”)
bits per inch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . bpi
bits per second . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . bps
brake horsepower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . bhp
British thermal unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Btu
capture unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . c.u.
centimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . cm
centipoise. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . cp
centistoke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . cSt
coulomb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C
counts per second . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . cps
cubic centimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . cm3
cubic foot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft3
cubic feet per barrel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft3/bbl
cubic feet per day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft3/D
cubic feet per minute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft3/min
cubic feet per pound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft3/lbm
cubic feet per second . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft3/s
cubic inch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . in.3
cubic meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . m3
cubic millimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mm3
cubic yard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . yd3
curie . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ci
dalton. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Da
darcy, darcies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D
day (customary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D
day (metric). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . d
dead-weight ton. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DWT
decibel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . dB
degree (American Petroleum Institute). . . . . . . . . . . . . . . . . . . . . . . . . . . °API
degree Celsius . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . °C
degree Fahrenheit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . °F
degree Kelvin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See “kelvin”
degree Rankine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . °R
dots per inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . dpi
electromotive force. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . emf
electron volt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . eV
farad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F
feet per minute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft/min
feet per second. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft/s
foot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft
foot-pound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft-lbf
gallon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . gal
gallons per day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . gal/D
gallons per minute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . gal/min
gigabyte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gbyte
gigahertz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GHz
gigapascal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GPa
gigawatt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GW
gram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . g
hertz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hz
horsepower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . hp
horsepower-hour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . hp-hr
hour (customary). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . hr
hour (metric). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . h
hydraulic horsepower. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . hhp
inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . in.
inches per second . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . in./s
joule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J
kelvin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . K
kilobyte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . kB
kilogram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . kg
kilogram-meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . kg-m
kilohertz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . kHz
kilojoule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . kJ
kilometer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . km
kilopascal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . kPa
kilopound (force) (1,000 lbf) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . klbf
kilovolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . kV
kilowatt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . kW
kilowatt-hour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . kW-hr
kips per square inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ksi
Appendix G
lines per inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . lpi
lines per minute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . lpm
lines per second . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . lps
liter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L
megabyte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MB
megagram (metric ton) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mg
megahertz. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MHz
megajoule . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MJ
meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . m
metric ton (tonne) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . t or Mg
mho per meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ω/m
microsecond. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . µs
mile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spell out
miles per hour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mph
milliamperes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mA
millicurie . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mCi
millidarcy, millidarcies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mD
milliequivalent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . meq
milligram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mg
milliliter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mL
millimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mm
millimho . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mmho
million cubic feet (million = 106) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MMcf
million cubic feet per day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MMcf/D
million electron volts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MeV
million standard cubic feet per day . . . . . . . Use MMcf/D instead of MMscf/D(see “standard cubic foot”)
milliPascal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mPa
millisecond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ms
millisiemens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mS
millivolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mV
mils per year . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mil/yr
minute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . min
mole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mol
nanosecond . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ns
newton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N
ohm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ohm
ohm-centimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ohm-cm
ohm-meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ohm-m
ounce. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . oz
parts per million . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ppm
pascal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pa
picofarad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pF
pint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . pt
porosity unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . p.u.
pound (force) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . lbf
pound (mass) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . lbm
pound per cubic foot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . lbm/ft3
pound per gallon. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . lbm/gal
pounds of proppant added . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ppa
pounds per square inch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . psi
pounds per square inch absolute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . psia
pounds per square inch gauge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . psig
pounds per thousand barrels (salt content). . . . . . . . . . . . . . . . . . . . . . . . . ptb
quart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . qt
reservoir barrel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . res bbl
reservoir barrel per day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RB/D
revolutions per minute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . rpm
saturation unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . s.u.
second . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . s
shots per foot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . spf
specific gravity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . sg
square . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . sq
square centimeter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . cm2
square foot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ft2
square inch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . in.2
square meter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . m2
square mile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . sq mile
square millimeter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . mm2
standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . std
standard cubic feet per day. . . . . . . . . . . . . . . . . . . . Use ft3/D instead of scf/D(see “standard cubic foot”)
standard cubic foot . . . . . . . . . . . . . . . . . Use ft3 or cf as specified on this list.Do not use scf unless the standard
conditions at which the measurement was made are specified.
The straight volumetric conversion factoris 1 ft3 = 0.02831685 m3
stock-tank barrel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . STB
stock-tank barrels per day. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . STB/D
stoke . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . St
teragram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tg
thousand cubic feet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mcf
thousand cubic feet per day. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mcf/D
thousand pounds per square inch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . kpsi
thousand standard cubic feet per day . . . . . . . . Use Mcf/D instead of Mscf/D (see “standard cubic foot”)
tonne (metric ton). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . t
trillion cubic feet (trillion = 1012) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tcf
trillion cubic feet per day . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tcf/D
volt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V
volume percent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vol%
volume per volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vol/vol
watt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . W
weight percent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . wt%
yard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . yd
year (customary) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . yr
year (metric) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . a
Ω
Appendix G
277
Unit Abbreviations
Appendix G
278
Appendix H References
1. Overton HL and Lipson LB: “A Correlation of the ElectricalProperties of Drilling Fluids with Solids Content,” Transactions,AIME (1958) 213.
2. Desai KP and Moore EJ: “Equivalent NaCl Concentrations fromIonic Concentrations,” The Log Analyst (May–June 1969).
3. Gondouin M, Tixier MP, and Simard GL: “An Experimental Studyon the Influence of the Chemical Composition of Electrolytes onthe SP Curve,” JPT (February 1957).
4. Segesman FF: “New SP Correction Charts,” Geophysics(December 1962) 27, No. 6, PI.
5. Alger RP, Locke S, Nagel WA, and Sherman H: “The Dual SpacingNeutron Log–CNL,” paper SPE 3565, presented at the 46th SPEAnnual Meeting, New Orleans, Louisiana, USA (1971).
6. Segesman FF and Liu OYH: “The Excavation Effect,”Transactions of the SPWLA 12th Annual Logging Symposium(1971).
7. Burke JA, Campbell RL Jr, and Schmidt AW: “The Litho-PorosityCrossplot,” Transactions of the SPWLA 10th Annual LoggingSymposium (1969), paper Y.
8. Clavier C and Rust DH: “MID-PLOT: A New LithologyTechnique,” The Log Analyst (November–December 1976).
9. Tixier MP, Alger RP, Biggs WP, and Carpenter BN: “DualInduction-Laterolog: A New Tool for Resistivity Analysis,” paper713, presented at the 38th SPE Annual Meeting, New Orleans,Louisiana, USA (1963).
10. Wahl JS, Nelligan WB, Frentrop AH, Johnstone CW, andSchwartz RJ: “The Thermal Neutron Decay Time Log,” SPEJ(December 1970).
11. Clavier C, Hoyle WR, and Meunier D: “QuantitativeInterpretation of Thermal Neutron Decay Time Logs, Part I andII,” JPT (June 1971).
12. Poupon A, Loy ME, and Tixier MP: “A Contribution to ElectricalLog Interpretation in Shaly Sands,” JPT (June 1954).
13. Tixier MP, Alger RP, and Tanguy DR: “New Developments inInduction and Sonic Logging,” paper 1300G, presented at the34th SPE Annual Meeting, Dallas, Texas, USA (1959).
14. Rodermund CG, Alger RP, and Tittman J: “Logging EmptyHoles,” OGJ (June 1961).
15. Tixier MP: “Evaluation of Permeability from Electric LogResistivity Gradients,” OGJ (June 1949).
16. Morris RL and Biggs WP: “Using Log-Derived Values of WaterSaturation and Porosity,” Transactions of the SPWLA 8thAnnual Logging Symposium (1967).
17. Timur A: “An Investigation of Permeability, Porosity, andResidual Water Saturation Relationships for SandstoneReservoirs,” The Log Analyst (July–August 1968).
18. Wyllie MRJ, Gregory AR, and Gardner GHF: “Elastic WaveVelocities in Heterogeneous and Porous Media,” Geophysics(January 1956) 21, No. 1.
19. Tixier MP, Alger RP, and Doh CA: “Sonic Logging,” JPT (May1959) 11, No. 5.
20. Raymer LL, Hunt ER, and Gardner JS: “An Improved SonicTransit Time-to-Porosity Transform,” Transactions of theSPWLA 21st Annual Logging Symposium (1980).
21. Coates GR and Dumanoir JR: “A New Approach to ImprovedLog-Derived Permeability,” The Log Analyst (January–February1974).
22. Raymer LL: “Elevation and Hydrocarbon Density Correction forLog-Derived Permeability Relationships,” The Log Analyst(May–June 1981).
23. Westaway P, Hertzog R, and Plasic RE: “The GammaSpectrometer Tool, Inelastic and Capture Gamma RaySpectroscopy for Reservoir Analysis,” paper SPE 9461,presented at the 55th SPE Annual Technical Conferenceand Exhibition, Dallas, Texas, USA (1980).
24. Quirein JA, Gardner JS, and Watson JT: “Combined NaturalGamma Ray Spectral/Litho-Density Measurements Applied toComplex Lithologies,” paper SPE 11143, presented at the 57thSPE Annual Technical Conference and Exhibition, New Orleans,Louisiana, USA (1982).
25. Harton RP, Hazen GA, Rau RN, and Best DL: “ElectromagneticPropagation Logging: Advances in Technique andInterpretation,” paper SPE 9267, presented at the 55th SPEAnnual Technical Conference and Exhibition, Dallas, Texas,USA (1980).
26. Serra O, Baldwin JL, and Quirein JA: “Theory and PracticalApplication of Natural Gamma Ray Spectrometry,” Transactionsof the SPWLA 21st Annual Logging Symposium (1980).
27. Gardner JS and Dumanoir JL: “Litho-Density LogInterpretation,” Transactions of the SPWLA 21st AnnualLogging Symposium (1980).
28. Edmondson H and Raymer LL: “Radioactivity LoggingParameters for Common Minerals,” Transactions of the SPWLA20th Annual Logging Symposium (1979).
29. Barber TD: “Real-Time Environmental Corrections for thePhasor Dual Induction Tool,” Transactions of the SPWLA 26thAnnual Logging Symposium (1985).
30. Roscoe BA and Grau J: “Response of the Carbon-OxygenMeasurement for an Inelastic Gamma Ray Spectroscopy Tool,”paper SPE 14460, presented at the 60th SPE Annual TechnicalConference and Exhibition, Las Vegas, Nevada, USA (1985).
Appendix H
31. Freedman R and Grove G: “Interpretation of EPT-G Logs in thePresence of Mudcakes,” paper presented at the 63rd SPEAnnual Technical Conference and Exhibition, Houston, Texas,USA (1988).
32. Gilchrist WA Jr, Galford JE, Flaum C, Soran PD, and Gardner JS:“Improved Environmental Corrections for CompensatedNeutron Logs,” paper SPE 15540, presented at the 61st SPEAnnual Technical Conference and Exhibition, New Orleans,Louisiana, USA (1986).
33. Tabanou JR, Glowinski R, and Rouault GF: “SP Deconvolutionand Quantitative Interpretation in Shaly Sands,” Transactionsof the SPWLA 28th Annual Logging Symposium (1987).
34. Kienitz C, Flaum C, Olesen J-R, and Barber T: “Accurate Loggingin Large Boreholes,” Transactions of the SPWLA 27th AnnualLogging Symposium (1986).
35. Galford JE, Flaum C, Gilchrist WA Jr, and Duckett SW:“Enhanced Resolution Processing of Compensated NeutronLogs, paper SPE 15541, presented at the 61st SPE AnnualTechnical Conference and Exhibition, New Orleans, Louisiana,USA (1986).
36. Lowe TA and Dunlap HF: “Estimation of Mud Filtrate Resistivityin Fresh Water Drilling Muds,” The Log Analyst (March–April1986).
37. Clark B, Luling MG, Jundt J, Ross M, and Best D: “A Dual DepthResistivity for FEWD,” Transactions of the SPWLA 29th AnnualLogging Symposium (1988).
38. Ellis DV, Flaum C, Galford JE, and Scott HD: “The Effect ofFormation Absorption on the Thermal Neutron PorosityMeasurement,” paper presented at the 62nd SPE AnnualTechnical Conference and Exhibition, Dallas, Texas, USA (1987).
39. Watfa M and Nurmi R: “Calculation of Saturation, SecondaryPorosity and Producibility in Complex Middle East CarbonateReservoirs,” Transactions of the SPWLA 28th Annual LoggingSymposium (1987).
40. Brie A, Johnson DL, and Nurmi RD: “Effect of Spherical Poreson Sonic and Resistivity Measurements,” Transactions of theSPWLA 26th Annual Logging Symposium (1985).
41. Serra O: Element Mineral Rock Catalog, Schlumberger (1990).
42. Grove GP and Minerbo GN: “An Adaptive Borehole CorrectionScheme for Array Induction Tools,” Transactions of the SPWLA32nd Annual Logging Symposium, Midland, Texas, USA, June16–19, 1991, paper F.
43. Barber T and Rosthal R: “Using a Multiarray Induction Tool toAchieve Logs with Minimum Environmental Effects,” paper SPE22725, presented at SPE Annual Technical Conference andExhibition, Dallas, Texas, USA, October 6–9, 1991.
44. Moran JH: “Induction Method and Apparatus for InvestigatingEarth Formations Utilizing Two Quadrature Phase Components ofa Detected Signal,” US Patent No. 3,147,429 (September 1, 1964).
45. Barber TD: “Phasor Processing of Induction Logs IncludingShoulder and Skin Effect Correction,” US Patent No. 4,513,376(September 11, 1984).
46. Barber T et al.: “Interpretation of Multiarray Induction Logs in Invaded Formations at High Relative Dip Angles,” The LogAnalyst 40, no. 3 (May–June 1990): 202–217.
47. Anderson BI and Barber TD: Induction Logging, Sugar Land,Texas, USA: Schlumberger Wireline & Testing, 1995 (SMP-7056).
48. Gerritsma CJ, Oosting PH, and Trappeniers NJ: “Proton Spin-Lattice Relaxation and Self Diffusion in Methanes, II,” Physica51 (1971), 381–394.
49. Wyllie MRJ and Rose WD: “Some Theoretical ConsiderationsRelated to the Quantitative Evaluation of the PhysicalCharacteristics of Reservoir Rock from Electrical Log Data,”JPT 2 (1950), 189.
Appendix H
279
References
Recommended