Effects of Segmentation and Skeletonization Algorithms on Pore Networks and Predicted Multiphase-Transport Properties of Reservoir-Rock Samples
- Nasiru Abiodun Idowu (FEI Lithicon Digital Rock Services) | Cyril Nardi (FEI Lithicon Digital Rock Services) | Haili Long (FEI Lithicon Digital Rock Services) | Trond Varslot (FEI Lithicon Digital Rock Services) | Pål-Eric Øren (FEI Lithicon Digital Rock Services)
- Document ID
- Society of Petroleum Engineers
- SPE Reservoir Evaluation & Engineering
- Publication Date
- November 2014
- Document Type
- Journal Paper
- 473 - 483
- 2014.Society of Petroleum Engineers
- flow in porous media, image analysis, digital rock physics, pore network modelling
- 0 in the last 30 days
- 396 since 2007
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Networks of large pores connected by narrower throats (pore networks) are essential inputs into network models that are routinely used to predict transport properties from digital rock images. Extracting pore networks from microcomputed-tomography (micro-CT) images of rocks involves a number of steps: filtering, segmentation, skeletonization, and others. Because of the amount of clay and its distribution, the segmentation of micro-CT images is not trivial, and different algorithms exist for achieving this. Similarly, several methods are available for skeletonizing the segmented images and for extracting the pore networks. The nonuniqueness of these processes raises questions about the predictive power of network models. In the present work, we evaluate the effects of these processes on the computed petrophysical and multiphase-flow properties of reservoir-rock samples.
By use of micro-CT images of reservoir sandstones, we first apply three different segmentation algorithms and assess the effects of the different algorithms on estimated porosity, amount of clay, and clay distribution. Single-phase properties are computed directly on the segmented images and compared with experimental data. Next, we extract skeletons from the segmented images by use of three different algorithms. On the pore networks generated from the different skeletons, we simulate two-phase oil/water and three-phase gas/oil/water displacements by use of a quasistatic pore-network model.
Analysis of the segmentation results shows differences in the amount of clay, in the total porosity, and in the computed singlephase properties. Simulated results show that there are differences in the network-predicted single-phase properties as well. However, predicted multiphase-transport properties from the different networks are in good agreement. This indicates that the topology of the pore space is well preserved in the extracted skeleton. Comparison of the computed capillary pressure and relative permeability curves for all networks with available experimental data shows good agreements.
By use of a segmentation that captures porosity and microporosity, we show that the extracted networks can be used to reliably predict multiphase-transport properties, irrespective of the algorithms used.
|File Size||921 KB||Number of Pages||11|
Arns, C.H., Knackstedt, M.A., Pinczewski, V.W., et al. 2004. Virtual Permeametry on Microtomographic Images. J. Pet. Sci. Eng. 45 (1–2): 41–46. http://dx.doi.org/10.1016/j.petrol.2004.05.001.
Bakke, S., and Øren, P.E. 1997. 3-D Pore-Scale Modelling of Sandstones and Flow Simulations in the Pore Networks. SPE J. 2 (2): 136–149. SPE-35479-PA. http://dx.doi.org/10.2118/35479-PA.
Baldwin, C.A., Sederman, A.J., Mantle, M.D., et al. 1996. Determination and Characterization of the Structure of a Pore Space from 3D Volume Images. J. Colloid Interf. Sci. 181 (1): 79–92. http://dx.doi.org/10.1006/jcis.1996.0358.
Bhattad, P., Willson, C.S., and Thompson, K.E. 2011. Effect of Network Structure on Characterization and Flow Modeling Using X-ray Micro-Tomography Images of Granular and Fibrous Porous Media. Transport Porous Med. 90 (2): 363–391. http://dx.doi.org/10.1007/s11242-011-9789-7.
Coles, M.E., Spanne, P., Muegge, E.L., et al. 1994. Computer Microtomography of Reservoir Core Samples. Oral presentation of paper SCA-9401 given at the International Symposium of the Society of Core Analysts, Stavanger, Norway, 12–14 September.
Collins, T.J. 2007. ImageJ for Microscopy. BioTechniques 43 (S1): S25-S30. http://dx.doi.org/10.2144/000112517.
Dong, H. and Blunt, M.J. 2009. Pore-Network Extraction from Micro-Computerized-Tomography Images. Phys. Rev. E 80 (3): 036307. http://dx.doi.org/10.1103/PhysRevE.80.036307.
Dong, H., Fjeldstad, S., Alberts, L., et al. 2008. Pore Network Modelling on Carbonate: A Comparative Study of Different Micro-CT Network Extraction Methods. Oral presentation of paper SCA2008–31 given at the International Symposium of the Society of Core Analysts, Abu Dhabi, UAE, 29 October–2 November.
Ferreol, B. and Rothman, D.H. 1995. Lattice-Boltzmann Simulations of Flow Through Fontainebleau Sandstone. Transport Porous Med. 20 (1–2): 3–20. http://dx.doi.org/10.1007/BF00616923.
Idowu, N.A. and Blunt, M.J. 2010. Pore-Scale Modelling of Rate Effects in Waterflooding. Transport Porous Med. 83 (1): 151–169. http://dx.doi.org/10.1007/s11242-009-9468-0.
Idowu, N., Nardi, C., Long, H., et al. 2012. Pore-Scale Modelling: Effects of Network Properties on Predictive Capabilities. Oral presentation of paper SCA 2012-35 given at the International Symposium of the Society of Core Analysts, Aberdeen, Scotland, UK, 27–30 August.
Idowu, N., Nardi, C., Long, H., et al. 2013. Improving Digital Rock Physics Predictive Potential for Relative Permeabilities from Equivalent Pore Networks. Oral presentation of paper SCA 2013-17 given at the International Symposium of the Society of Core Analysts, Napa Valley, California, 16–19 September.
Kalam, Z., Al Dayyani, T., Clark A., et al. 2010. Case Study in Validating Capillary Pressure Curves, Relative Permeability and Resistivity Index of Carbonates from X-ray Micro Tomography Images. Oral presentation of paper SCA2010-02 given at the International Symposium of the Society of Core Analysts, Halifax, Nova Scotia, Canada, 4–7 October.
Kalam, Z., Seraj, S., Bhatti, Z., et al. 2012. Relative Permeability Assessment in a Giant Carbonate Reservoir using Digital Rock Physics. Oral presentation of paper SCA2012-03 given at the International Symposium of the Society of Core Analysts, Aberdeen, Scotland, UK, 27–30 August.
Lee, T.C., Kashyap, R.L., and Chu, C.N. 1994. Building Skeleton Models via 3-D Medial Surface Axis Thinning Algorithms. Comput. Vision Graph. 56 (6): 462–478. http://dx.doi.org/10.1006/cgip.1994.1042.
Liang, Z., Ioannidis, M.A., and Chatzis, I. 2000. Geometric and Topological Analysis of Three-Dimensional Porous Media: Pore Space Partitioning Based on Morphological Skeletonization. J. Colloid Interf. Sci. 221 (1): 13–24. http://dx.doi.org/10.1006/jcis.1999.6559.
Lindquist, W.B., Lee, S.M., Coker, D., et al. 1996. Medial Axis Analysis of Void Structure in Three-Dimensional Tomographic Images of Porous Media. J. Geophys. Res. 101 (B4): 8297–8310. http://dx.doi.org/101029/95JB03039.
Long, H., Nardi, C., Idowu, N. et al. 2013. Multi-Scale Imaging and Modeling Workflow to Capture and Characterise Microposity in Sandstone. Oral presentation of paper SCA 2013-13 given at the International Symposium of the Society of Core Analysts, Napa Valley, California, 16–19 September.
Meakin, P. and Tartakovsky, A.M. 2009. Modeling and Simulation of Pore-Scale Multiphase Fluid Flow and Reactive Transport in Fractured and Porous Media. Rev. Geophys 47 (3): RG3002. http://dx.doi.org/10.1029/2008RG000263.
Nardi, C., Lopez, O., Øren, P.E., et al. 2009. Pore-Scale Modeling of Three-Phase Flow: Comparative Study with Experimental Reservoir Data. Oral presentation of paper SCA2009-30 given at the International Symposium of the Society of Core Analysts, Noordwijk, The Netherlands 27–30 September
Øren, P.E. and Bakke, S. 2002. Process Based Reconstruction of Sandstones and Prediction of Transport Properties. Transport Porous Med. 46 (2–3): 311–343. http://dx.doi.org/10.1023/A:1015031122338.
Øren, P.E., Bakke, S. and Arntzen, O.J. 1998. Extending Predictive Capabilities to Network Models. SPE J. 3 (4): 324–336. SPE-52052-PA. http://dx.doi.org/10.2118/52052-PA.
Øren, P.E., Bakke, S., and Held, R. 2007. Direct Pore-Scale Computation of Material and Transport Properties on North Sea Reservoir Rocks. Water Resour. Res. 43 (12): W12S04. http://dx.doi.org/10.1029/2006WR005754.
Petersen, E.B. Jr., Lohne, A., Vatne, K.O., et al. 2008. Relative Permeabilities for Two- and Three-Phase Flow Processes Relevant to the Depressurization of the Statfjord Field. Oral presentation of paper SCA2008-23 given at the International Symposium of the Society of Core Analysts, Abu Dhabi, UAE, 29 October – 2 November.
Raeini, A.Q., Blunt, M.J., and Bijeljic, B. 2012. Modelling Two-Phase Flow in Porous Media at the Pore Scale Using the Volume-of-Fluid Method. J. Comput. Phys. 231 (17): 5653–5668. http://dx.doi.org/10.1016/j.jcp.2012.04.011.
Ramstad, T., Idowu, N., Nardi, C. et al. 2012. Relative Permeability Calculations from Two-Phase Flow Simulations Directly on Digital Images of Porous Rocks. Transport Porous Med. 94 (2): 487–504. http://dx.doi.org/10.1007/s11242-011-9877-8.
Shapiro, L.G. and Stockman, G.C. 2001. Computer Vision. Upper Saddle River, New Jersey: Prentice Hall.
Sheppard, A.P., Sok, R.M., and Averdunk, H. 2005. Improved Pore Network Extraction Methods. Oral presentation of paper SCA2005-20 given at the International Symposium of the Society of Core Analysts, Toronto, Canada, 21–25 August.
Sheppard, A.P., Sok, R.M., and Averdunk, H. 2004. Techniques for Image Enhancement and Segmentation of Tomographic Images of Porous Materials. Physica A 339 (1–2): 145–151. http://dx.doi.org/10.1016/j.physa.2004.03.057.
Silin, D. and Patzek, T. 2006. Pore Space Morphology Analysis Using Maximal Inscribed Spheres. Physica A 371 (2006): 336–360. http://dx.doi.org/10.1016/j.physa.2006.04.048.
Smith, S.M. and Brady, J.M. 1997. SUSAN—A New Approach to Low Level Image Processing. Int. J. Comput. Vision 23 (1): 45–78. http://dx.doi.org/10.1023/A:1007963824710.
Sussman, M., Smereka, P., and Osher, S. 1994. A Level Set Approach for Computing Solutions to Incompressible Two-Phase Flow. J. Comput. Phys. 114 (1): 146–159. http://dx.doi.org/10.1006/jcph.1994.1155.
Valvatne, P.H., and Blunt, M.J. 2004. Predictive Pore-Scale Modeling of Two-Phase Flow in Mixed Wet Media. Water Resour. Res. 40 (7):
Vogel, H.J., Tölke, J., Schulz, V.P., et al. 2005. Comparison of a Lattice-Boltzmann model, a Full Morphology Model, and a Pore Network Model for Determining Capillary Pressure-Saturation Relationships. Vadose Zone J. 4 (2): 380–388. http://dx.doi.org/10.2136/vzj2004.0114.