Upload
cristian-medina
View
111
Download
2
Tags:
Embed Size (px)
Citation preview
1
Petrophysical Study of Reservoir Rocks:
Use of Image Analysis Software (IAS) and Mercury Injection
Capillary Pressure (MICP) Data
Cristian R. MedinaApril 2015
Acknowledgements
John Rupp, Barb Hill, Carley Gasaway, and Drew Packman (IGS) Steve Greb and Dave Harris (KGS)Ron Riley and Matt Erenpreiss (ODNR)
Source: Archie, 1950
Scale Considerations
6,090 ft.
Why Porosity ()?
Storage Capacity:
Units:
Other geologic aspects where porosity is relevant:• Oil and gas reservoir
• Groundwater• Injection of waste fluids
• Gas storage
Trapping Mechanisms
Source: IPCC, 2005
Pore Characterization: Instrumentation
• Helium porosimetry• Helium/N/CO2 adsorption• Scanning Electron Microscopy (SEM)• (Ultra) Small Angle Neutron Scattering (SANS/USANS)• Optical Microscopy and Image Analysis Software (IAS)• Mercury Injection Capillary Pressure (MICP)
8
Scale and Instruments
SEM images taken by Carley Gasaway
MethodologyImageJ is a public domain image processing program developed at the National Institutes of Health. The source code for ImageJ is freely available.
Porosity (f)• f from core
analysis•Two-Dimensional f
~1 mm
Saturation: 0-255
Saturation: 20-255
Saturation: 40-255
Saturation: 60-255
Saturation: 80-255
Saturation: 100-255
Saturation: 120-255
Adjusting Saturation
Adjusting Saturation
3,465 ft.
Methodology: Thin Sections, Photomicrographs, and Pre-processing
Thin Section (30 mm)1mm=103 microns (mm)
Adjusting Pore Size
14
Identifying Micro- Versus Macro-Porosity Using ImageJ
15
Optical Microscopy and Image Analysis Software:Visualizing Porosity, Permeability, and Depth in
Sandstones
Petrophysics Study on Carbonates from the Cambro-Ordovician Knox
SupergroupMeasured
depth, Top of Knox (ft)
0
2500
10000
15000
17
Optical Microscopy and Image Analysis Software:Visualizing Porosity and Permeability in
Carbonates
What can we Measure?
19
Elements of a Pore Measured on ImageJ
• Area (A)• Perimeter (P)• Major/Minor Axis• Circularity (C)• Aspect ratio (AR)• Roundness (R)
𝐶=4∗𝜋∗𝐴𝑃
𝑅=4∗𝐴
𝜋∗(𝑀𝑎𝑗𝑜𝑟 𝐴𝑥𝑖𝑠)22 mm.
20
Results: Porosity from Core Analysis vs. IAS
#1
#2 #3
0.1 1 100
1
10
Sand-stonesCar-bon-ates
Core Porosity (%)
2D P
oros
ity
(All
Pore
s)
21
Resolving Discrepancy #1
F = 0.3 F = 1.9
22
ID #162029 Depth: 1646 ft
Fcore = 1.4
Resolving Discrepancy #2
Pore Throat Radius (microns)
23
Effect of Dual Porosity in Carbonates
Resolving Discrepancy #3
Fcore = 2.6
24
Excluding Pixel-Size ‘Pores’
250.1 1 100
1
10
Sand-stones
Core Porosity (%)
2D P
oros
ity
(All
Pore
s)
Results: Porosity from Core Analysis vs. IAS
Porosity from IAS and its Dependency With Pore Size
27
Excluding Pixel-Size ‘Pores’
Pore Shape
Relationships
29
Mercury Injection Capillary Pressure (MICP)
Source: Crain's petrophysical handbook (www.spec2000.net)
30
Data Interpretation and Analysis
Intrusio
n pressure values a
re directly converted
into the corre
sponding pores size by usin
g the
Washburn equation. This is a
straightforward
calculation.
Source: Bliefnick and Kaldi, 1996
31
Theory and Key-Parameters
∆ 𝑃=2𝛾 cos𝜃𝑟𝑝𝑜𝑟𝑒
Contact Angle (θ)
32
Limitations: It Measures the Largest Entrance Towards a
Pore.
33
34
Results from MICP (Indirect Method)
Pore Size between ~[0.1 - 25] microns
Results from ImageJ (Direct Method)
Pore Size between ~[15 - 300] microns
35
Conclusions
• Image Analysis Software provides a good porosity estimator.
• The study of micro- vs. macro- porosity is limited by instrument resolution. Therefore,
multiple techniques should be used in a complementary way.
• Pore shape descriptors and pore size distribution can shed light on reservoir
performance.
• ImageJ measures pores, whereas MICP describes the pore throats.
• Pore systems in carbonates are more complex than those in clastics. Therefore their
characterization is more challenging.
• MICP advantages: rock type, reservoir quality, and pore size distribution.
• Value of a thin section: $30. One MICP test: $500-900.
36
Questions?
ReferencesArchie, G.E., 1950, Introduction to petrophysics of reservoir rocks: AAPG Bulletin, v. 34, p. 943-961.
Bliefnick, D.M., and Kaldi, J.G., 1996, Pore geometry; control on reservoir properties, Walker Creek Field, Columbia and Lafayette counties, Arkansas: AAPG Bulletin, v. 80, p. 1027-1044.
Grove, C., and Jerram, D.A., 2011, jPOR: An ImageJ macro to quantify total optical porosity from blue-stained thin sections: Computers & Geosciences, v. 37, p. 1850-1859.
IPCC, 2005, IPCC Special Report on Carbon Dioxide Capture and Storage. Prepared by Working Group III of the Intergovernmental Panel on Climate Change: Cambridge, UK, Cambridge University Press.
Rasband, W.S., ImageJ, US National Institutes of Health, Bethesda, Maryland, USA, http://rsb.info.nih.gov/ij/, 1997–2009.