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8/7/2019 Geochemical Logging
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Borehole Elemental Concentration
Logs Now Available: A New Sourceof Geochemistry Data
Michael Herron, Susan Herron, Jim Grau
Schlumberger-Doll Research
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Leaps of Science Follow NewAnalytical Capabilities
• Well logging provides more data every day aboutearth formations than all laboratory sources in a
year
• Geochemical well logging is a new analyticalcapability
• Time for earth scientists to address this new
source of data
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ECS Tool and Data Processing Flow
AmBe Source
BGO Crystaland PMT
• Logging Speed:Logging Speed:Logging Speed:Logging Speed: 1800 ft/hr1800 ft/hr1800 ft/hr1800 ft/hr• Vertical Resolution:Vertical Resolution:Vertical Resolution:Vertical Resolution: 1.5 ft1.5 ft1.5 ft1.5 ft• Borehole Fluid:Borehole Fluid:Borehole Fluid:Borehole Fluid: AllAllAllAll• Tool Size:Tool Size:Tool Size:Tool Size: 5.0 in O. D.5.0 in O. D.5.0 in O. D.5.0 in O. D.
• Length:Length:Length:Length: 6.6 ft6.6 ft6.6 ft6.6 ft• Maximum Temp:Maximum Temp:Maximum Temp:Maximum Temp: 350350350350 ooooFFFF• Maximum Pressure:Maximum Pressure:Maximum Pressure:Maximum Pressure: 20,000 psi20,000 psi20,000 psi20,000 psi• Min Hole Size:Min Hole Size:Min Hole Size:Min Hole Size: 6.00 in6.00 in6.00 in6.00 in
6.6 ft
Boron Sleeve
Electronics
Heat Sink
Internal
Dewar Flask
AcquisitionAcquisitionAcquisitionAcquisition
Spectral StrippingSpectral StrippingSpectral StrippingSpectral Stripping
SpectroLithSpectroLithSpectroLithSpectroLith
GammaGammaGammaGamma----Ray SpectraRay SpectraRay SpectraRay Spectra
Elemental YieldsElemental YieldsElemental YieldsElemental Yields
Dry Weight ElementsDry Weight ElementsDry Weight ElementsDry Weight ElementsSi, Ca, Fe, S, Ti, GdSi, Ca, Fe, S, Ti, GdSi, Ca, Fe, S, Ti, GdSi, Ca, Fe, S, Ti, Gd
Dry Weight LithologiesDry Weight LithologiesDry Weight LithologiesDry Weight LithologiesClay, Carbonate, Anhydrite, QFMClay, Carbonate, Anhydrite, QFMClay, Carbonate, Anhydrite, QFMClay, Carbonate, Anhydrite, QFM
Oxides ClosureOxides ClosureOxides ClosureOxides Closure
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What Do We Measure ?4 MeV neutron interactswith fomation:
Inelastic Interaction(multiple gamma-rays)
Slowing down of neutronthrough multiple scattering
Neutron Capture(multiple gamma-rays)
Gam ma-Ray Spectrum
Energy [MeV]
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ECS Gamma-Ray SpectrumInelastic and Capture
H
G d
0 5 0 1 0 0 1 5 0 2 0 0 2 5 0
Ine las t ic
C l
S iF e
LogScal
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Capture Gamma-Ray Spectroscopy
20
40
60
Silic Calci Iron Sulf Titani Gadolin
Capture Spectra
n
γ γγ γ
Oxides
0 5
80
100
120
0 2 4 0 1 2 0 1 2 3 0 5 0 1 3
Elemental Concentrations Lithology
Relative
Yields
Elemental Standards
Si
Ca
Fe
S
Closure
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ECS SpectroLithDry Weight Lithologies and Elements
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200
300
400
500
Open Hole Elemental Concentrations
epth, ft
0 50
600
700
800
900
Silicon wt%
0 20 40Calcium wt%
0 10 20Iron + .14Al wt%
0 10 20Sulfur wt%
0 2 4Titanium wt%
0 20 40Gadolinium ppm
D
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200
400
600
800
Open Hole Lithology
0 50 100
1000
1200
1400
1600
Dep
th
Clay, wt%0 50 100
Carbonate, wt%0 50 100Quartz-Feld-Mica, wt%
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Instant Petrophysical Evaluation
Nuclear spectroscopySLB exclusive hardwareSLB exclusive hardwareSLB exclusive hardwareSLB exclusive hardware
and interpretationand interpretationand interpretationand interpretation
400
600, ft+
Siliciclastics – Four patented applications
800
1000
De
pt
Lith2.6 3
GDen0.5
Por0.5
Por10
-110
4
Perm Res0 1
Sw
=Real-Time Petrophysics
Wireline & LWD
Triple Combo
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SDR Fourier Transform Infrared SpectroscopyQuantitative Mineralogy
• Recognized world-class
• Patented
• Best paper 1997 Society of Core
Analysts
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Sample A Qtz Ksp Plag Cal Mg-Cal Dol Sid Py Kaol 2:1 Al clay 2:1 Fe clay Fe-Chl
Actual 25 5 5 5 0 0 0 0 15 20 20 5
Texaco 26 4 3 5 0 0 0 0 16 19 22 5
Vendor 1 68 3 4 5 0 0 0 0 8 0
Vendor 2 44 1 5 2 0.1 0 0.1 23 11
Vendor 3 41 2 3 9 0 0 0 0 36 0
Sample B Qtz Ksp Plag Cal Mg-Cal Dol Sid Py Kaol 2:1 Al clay 2:1 Fe clay Fe-Chl
Actual 30 5 10 5 0 5 0 5 20 10 0 10
Texaco 31 2 8 4 0 4 0 3 21 13 0 10
11
12
9
Commercial XRD and Actual Mineralogy
Vendor 1 56 0 7 3 0 6 0 14 12 1
Vendor 2 34 1 8 3 0 6 0 4 24 18
Vendor 3 52 2 3 13 0 0 0 2 24 0
Sample C Qtz Ksp Plag Cal Mg-Cal Dol Sid Py Kaol 2:1 Al clay 2:1 Fe clay Fe-Chl
Actual 30 10 5 5 5 5 10 0 10 15 0 5
Texaco 30 8 4 5 5 4 10 0 10 16 0 5
Vendor 1 63 3 14 3 0 5 6 0 5 0
Vendor 2 39 2 6 4 0 7 14 0.2 15 10
Vendor 3 37 1 2 8 0 9 19 0 19 0
2
2
5
1
4
5
D. McCarty (Chevron)
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Sample A Qtz Ksp Plag Cal Mg-Cal Dol Sid Py Kaol 2:1 Al clay 2:1 Fe clay Fe-Chl
Actual 25 5 5 5 0 0 0 0 15 20 20 5
Texaco 26 4 3 5 0 0 0 0 16 19 22 5
Vendor 1 68 3 4 5 0 0 0 0 8 0
Vendor 2 44 1 5 2 0.1 0 0.1 23 11
Vendor 3 41 2 3 9 0 0 0 0 36 0
Sample B Qtz Ksp Plag Cal Mg-Cal Dol Sid Py Kaol 2:1 Al clay 2:1 Fe clay Fe-Chl
Actual 30 5 10 5 0 5 0 5 20 10 0 10
Texaco 31 2 8 4 0 4 0 3 21 13 0 10
11
12
9
Commercial XRD and Actual Mineralogy
Vendor 1 56 0 7 3 0 6 0 14 12 1
Vendor 2 34 1 8 3 0 6 0 4 24 18
Vendor 3 52 2 3 13 0 0 0 2 24 0
Sample C Qtz Ksp Plag Cal Mg-Cal Dol Sid Py Kaol 2:1 Al clay 2:1 Fe clay Fe-Chl
Actual 30 10 5 5 5 5 10 0 10 15 0 5
Texaco 30 8 4 5 5 4 10 0 10 16 0 5
Vendor 1 63 3 14 3 0 5 6 0 5 0
Vendor 2 39 2 6 4 0 7 14 0.2 15 10
Vendor 3 37 1 2 8 0 9 19 0 19 0
2
2
5
1
4
5
D. McCarty (Chevron)
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True and Estimated Mineral Concentrations
0
5
10
Quartz Opal-A Ortho. Olig. Calcite Dolomite Pyrite
True CompositionEstimated from FT-IR
0 50 100
15
20
25
30
35
40
45
Sample
1.230 50 100
1.100 50
0.570 50
1.060 50 100
0.950 50 100
1.730 50
0.07
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True and Estimated Mineral Concentrations
0
5
10
Illite Smec. Kaol. Chlor. Musc. Glauc.Biotite
True CompositionEstimated from FT-IR
0 50
15
20
25
30
35
40
45
Sample
1.600 50
1.080 50
0.570 50
0.970 50
0.570 50
0.660 50
0.13
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Development of Applications
• Total clay from chemical data• Matrix density from chemical data
• More for ou to develo
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Clay and Gamma Ray
0
50
100
Clay wt%
Well 1 Well 2 Well 3 Well 4
100
y wt%
Well 5 Well 6 Well 7 Well 8
0
Cl
0 100 2000
50
100
Clay w
t%
Gamma Ray
Well 9
0 100 200
Gamma Ray
Well 10
0 100 200
Gamma Ray
Well 11
0 100 200
Gamma Ray
Well 12
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0 10 200
50
100
Clay wt%
Thorium ppm0 5 10
Uranium ppm0 2.5 5
Potassium wt%
100
t%
Clay Elemental Relationships - Well 3
0 10 200
50
Cla
y
Aluminum wt%0 1 2
Titanium wt%0 5 10
Gadolinium
0 25 500
50
100
Clay wt%
Silicon wt%0 15 30
Iron wt%0 20 40
Calcium wt%
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Clay Elemental Relationships - Well 5
100
0 10 200
50
100
Clay wt%
Thorium ppm0 5 10
Uranium ppm0 2.5 5
Potassium wt%
100
wt%
0 10 200
C
la
Aluminum wt%0 1 2
Titanium wt%0 5 10
Gadolinium
0 25 500
50
100
Clay wt%
Silicon wt%0 15 30
Iron wt%0 20 40
Calcium wt%
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100
Clay Elemental Relationships - Well 6
0 10 200
50
100
Clay wt%
Thorium ppm0 5 10
Uranium ppm0 2.5 5
Potassium wt%
100
wt%
0 10 200
C
la
Aluminum wt%0 1 2
Titanium wt%0 5 10
Gadolinium
0 25 500
50
100
Clay wt%
Silicon wt%0 15 30
Iron wt%0 20 40
Calcium wt%
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Aluminum and Clay100
Clay wt%
wt%
0
50
100
Clay wt%
Well 1 Well 2 Well 3 Well 4
50
100
lay wt%
Well 5 Well 6 Well 7 Well 8
C
la
Clay wt%
0
C
0 10 200
50
100
Clay wt%
Aluminum wt%
Well 9
0 10 20Aluminum wt%
Well 10
0 10 20Aluminum wt%
Well 11
0 10 20Aluminum wt%
Well 12
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Estimation of Aluminum
0
10
20
Aluminum wt%
Well 1 Well 2 Well 3 Well 4
10
20
inum wt%
Well 5 Well 6 Well 7 Well 8
0
A
lu
0 10 200
10
20
Aluminum wt%
Aluminum Emulator
Well 9
0 10 20Aluminum Emulator
Well 10
0 10 20Aluminum Emulator
Well 11
0 10 20Aluminum Emulator
Well 12
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SpectroLith Clay from Si, Ca, Fe
0
50
100
Clay wt%
Well 1 Well 2 Well 3 Well 4
100
wt%
Well 5 Well 6 Well 7 Well 8
0
C
lay
0 50 1000
50
100
Clay wt%
Estimated Clay
Well 9
0 50 100Estimated Clay
Well 10
0 50 100Estimated Clay
Well 11
0 50 100Estimated Clay
Well 12
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Changes in ρma with Silicon
2.8
3
3.2
3.4
3.6
Matrix Density, g cm-3
Silicon, wt %
0 20 40.
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Variation of ρma with Calcium
2.8
3
3.2
3.4
3.6
2.8
3
3.2
3.4
3.6
Matrix Density, g cm-3
0 20 40.
Calcium, wt %Silicon, wt %
0 20 40.
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ρma Increases with Iron
2.8
3
3.2
3.4
3.6
Matrix Density, g cm-3
2.8
3
3.2
3.4
3.6
0 20 402.6
2.8
3
3.2
3.4
3.6
Iron, wt%
Matrix Den
sity, g cm-3
Silicon, wt %
0 20 40.
0 20 40.
Calcium, wt %
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ρma
Also Increases with Sulfur
2.8
3
3.2
3.4
3.6
Matrix Density, g cm-3
2.8
3
3.2
3.4
3.6
0 10 20 302.6
2.8
3
3.2
3.4
3.6
Sulfur, wt%
Silicon, wt %
0 20 40.
0 20 40.
Calcium, wt %
0 20 402.6
2.8
3
3.2
3.4
3.6
Iron, wt%
Matrix Den
sity, g cm-3
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Density of Common Iron-bearing Minerals
4.5
5.0
5.5
, g cm-3
Pyrite
Hematite
0 20 40 60 802.5
3.0
3.5
4.0
Iron concentration, wt %
Grain densit
Illite
Quartz
GlauconiteChlorite
Siderite
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Regression Results
ρma = 2.620
Non-arkose & Subarkose
+ 0.0490
+ 0.2274 (Ca + 0.6 Na)
+ 1.993 (Fe + 0.14 Al)
+ 1.193 S
r = 0.967; std error 0.015 g cm-3
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Measured vs Computed Density
2.8
3
aad = 0.012 aad = 0.026
elements
aad = 0.01
Non-arkose Subarkose
2.6
2.6
2.8
3
E
stimated fro
m
aad = 0.0074 aad = 0.009
2.6 2.8 3
Matrix density from minerals
aad = 0.005
2.6 2.8 3 2.6 2.8 3
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XX100
Clay
QFM
Carbonate
Gamma ray
Pyrite
a b c ed
0 150
0 1
XX300
XX500
Dept
h, ft
Lithology, wt fraction
00.20.4
Porosity, pu
100
101
102
103
Permeability, md
100
101
102
R0 ohm-m
0 1
SW
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XX100
Clay
QFM
Carbonate
Pyrite
ca b
DRFT-IR Clay
XRD Clay
Clay
QFM
Carbonate
Pyrite
0 150
XX300
XX500
Depth, ft
Gamma Ray, API
0 1
Lithology, wt fraction
0 1
Lithology, wt fraction
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60
80
100
t %
a
60
80
100
b
0 50 100 150 2000
20
40
Gamma Ray (API)
Total Clay,
0 5 10 150
20
40
0.39 (100 – SiO2 – CaCO3 – 1.99 Fe)
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Clay
QFM
Carbonate
Pyrite
Oil
Free Water
Irreducible Water
Clay
QFM
Carbonate
Pyrite
Oil
Free Water
Irreducible Water
XX100
a b
XX300
XX500
Depth, ft
0 1
Formation, vol fraction
0 1
Formation, vol fraction
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Well-to-Well Gamma Ray-Resistivity
Sometimes these
Correlations are
And not repeatable
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0 50 100 150Gamma Ray (API)
0 50 100 150Gamma Ray (API)
ShapeSimilarity
Ambiguous Correlations with Gamma Ray
Depth (ft)
Well 1 Well 2
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Ambiguous Correlations with Gamma Ray
0 50 100 150
Gamma Ray (API)
0 50 100 150
Gamma Ray (API)
? ShapeSimilarity
Depth (ft)
Well 1 Well 2
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0 10 20 30 40
Calcium (wt %)0 10 20 30 40
Calcium (wt %)
Shape
Chemostratigraphy Lowers Ambiguity
Depth (ft)
&Absolute
Value
Well 1 Well 2
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This is the Chemostratigraphy Connection
Ca Connections
0 10 20 30 40 50Silicon (wt %)
0 10 20 30 40 50Silicon (wt %)
Si Connections
Depth (ft)
3
Well 2Well 1
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Leaps of Science Follow NewAnalytical Capabilities
• Induced gamma ray spectroscopy is nowbecoming a standard oilfield service
• More data in an hour than in a lab geochemist’s
lifetime• New elements are around the corner
• Challenge is on Academia and Industry to
maximize use of these new data
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