Sensitivity Analysis of the Effect of Pore Structure and Geometry on Petrophysical and Electrical Properties of Tight Media: Random Network Modeling

Document Type : Research Paper

Authors

1 Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, Canada

2 1-Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, Canada 2-PERM Inc. TIPM Laboratory, Calgary, Canada

Abstract

Several methodologies published in the literature can be used to construct realistic pore networks for simple rocks, whereas in complex pore geometry formations, as formed in tight reservoirs, such a construction still remains a challenge. A basic understanding of pore structure and topology is essential to overcome the challenges associated with the pore scale modeling of tight porous media. A stochastic random generation algorithm was employed to assess the effects of certain pore structure and geometries on the estimation of petrophysical and electrical properties of tight media through physically realistic 3D random networks. A Weibull truncated equation was used to predict the distribution of network pores and throats. An equivalent 3D pore network of Berea Sandstone was generated based on published pore and throat size distributions. The estimated porosity, absolute permeability, and formation factor of the reconstructed pore network are in good agreement with published laboratory measurements. Moreover, the estimated drainage and imbibition relative permeability curves are in a good match with corresponding experimental relative permeability curves. Subsequently, the effect of pore structure on basic core properties is evaluated by varying the Berea network pore size, throat size, and coordination number (connectivity) distributions. Finally, the effect of pore and throat geometries on two phase flow properties is investigated. The study shows the importance of taking into consideration the internal pore structure for petrophysical and electrical properties estimation.

Keywords


      [1]     Okabe H. and Blunt M. J., “Pore Space Reconstruction Using Multiple-point Statistics,” Journal of Petroleum Science and Engineering, 2005, 46, 121-137.##
      [2]     Okabe H., “Pore-scale modeling of carbonates,” Ph.D. Thesis, Imperial College, London, United Kingdom, 2004.##
      [3]     Blunt M. J., “Flow in Porous Media Pore-network Models and Multiphase Flow,” Current Opinion in Colloid & Interface Science, 2001, 6, 197-207.##
      [4]     Blunt M. J., Jackson M. D., Piri M., and Valvatne P. H., “Detailed Physics, Predictive Capabilities and Macroscopic Consequences for Pore-network Models of Multiphase Flow,” Advances in Water Resources, 2002, 25, 1069-1089.##
      [5]     Celia M. A., Reeves P. C., and Ferrand L. A., “Recent Advances in Pore Scale Models for Multiphase Flow in Porous Media,” Review of Geophysics, 1995, 33, 1049-1057.##
      [6]     Fatt I., “The Network Model of Porous Media,” Petroleum Transactions of AIME, 1956, 207, 144-181.##
      [7]     Chatzis I. and Dullien F. A. L., “Modeling Pore Structure by 2-D and 3-D Networks with Application to Sandstones,” Journal of Canadian Petroleum Technology, 1977, 16, 97-108.##
      [8]     Dixit A. B., McDougall S. R., and Sorbie K. S., “A Pore-level Investigation of Relative Permeability Hysteresis in Water-wet Systems,” SPE Journal, 1998, 3, 115- 123.##
      [9]     Grattoni C. A. and Dawe R. A., “Pore Structure Influence on the Electrical Resistivity of Saturated Porous Media,” in the SPE Latin America/Caribbean Petroleum Engineering Conference SPE 27044, 1994.##
    [10]    Jerauld G. R. and Salter S. J., “The Effect of Pore-structure on Hysteresis in Relative Permeability and Capillary Pressure: Pore-level Modeling,” Transport in Porous Media, 1990, 5, 103-151.##
    [11]    Lowry M. I. and Miller C. T., “Pore‐scale Modeling of Non-wetting‐phase Residual in Porous Media,” Water Resources Research, 1995, 31, 455-473.##
    [12]    Ören P. E. and Bakke S., “Process Based Reconstruction of Sandstones and Prediction of Transport Properties,” Transport in Porous Media, 2002, 46, 311-343.##
    [13]    Ören P. E. and Bakke S., “Reconstruction of Berea Sandstone and Pore-Scale Modeling of Wettability Effects,” Journal of Petroleum Science and Engineering, 2003, 39, 177-199.##
    [14]    Ören P. E., Bakke S., and Arntzen O. J., “Extending Predictive Capabilities to Network Models,” SPE Journal, 1998, 3, 324-336.##
    [15]    Patzek T. W., “Verification of a Complete Pore Network Simulator of Drainage and Imbibitions,” SPE Journal, 2001, 6, 144-156.##
    [16]    Piri M. and Blunt M. J., “Three-Dimensional Mixed-wet Random Pore-scale Network Modeling of Two-and Three-phase Flow in Porous Media:  Model Description,” Physical Review, 2005, 71.##
    [17]    Piri M. and Blunt M. J., “Three-Dimensional Mixed-wet Random Pore-Scale Network Modeling of Two-and Three-phase Flow in Porous Media. II. Results,” Physical Review, 2005, 71.##
    [18]    Valvatne P. H. and Blunt M. J., “Predictive Pore-scale Network Modeling,” in the SPE Annual Technical Conference and Exhibition, held in Denver CO., SPE 84550, 2003, 5-8.##
    [19]    Bakke S. and Ören P. E., “3-D Pore-scale Modeling of Sandstones and Flow Simulations in the Pore Networks,” SPE Journal, 1997, 2, 136-149.##
    [20]    Al-Kharusi A. S. and Blunt M. J., “Network Extraction from Sandstone and Carbonate Pore Space Images,” Journal of Petroleum Science and Engineering, 2007, 56, 219-231.##
    [21]    Dong H. and Blunt M. J., “Pore-network Extraction from Micro-computerized-tomography Images,” Physical Review E, 2009, 80, 197-216.##
    [22]    Chen S. and Gary D. D., “Lattice Boltzmann method for fluid flows,” Annual Review of Fluid Mechanics, 1998, 30, 329-364.##
    [23]    Gunstensen A. K. and Daniel H. R., “Lattice‐Boltzmann Studies of Immiscible Two‐phase Flow through Porous Media,” Journal of Geophysical Research: Solid Earth, 1993, 98, 6431-6441.##
    [24]    Hazlett R. D., Chen S. Y., and Soll W. E., “Wettability and Rate Effects on Immiscible Displacement: Lattice Boltzmann Simulation in Microtomographic Images of Reservoir Rocks,” Journal of Petroleum Science and Engineering, 1998, 20, 167-175.##
    [25]    Aguilera R., “Role of Natural Fractures and Slot Porosity on Tight Gas Sands,” in the SPE Unconventional Reservoirs Conference, Society of Petroleum Engineers SPE 114174, 2008.##
    [26]    Byrnes P. A., Cluff R. M., and Webb J. C., “Analysis of Critical Permeability, Capillary and Electrical Properties for Mesaverde Tight Gas Sandstones from Western US Basins,” Final Scientific/ Technical Report submitted to DOE and NETL, 2009.##
    [27]    Soeder D. and Randolph P., “Porosity, Permeability and Pore Structure of the Tight Mesaverde Sandstone,Piceance Basin and Colorado,” SPE Formation Evaluation, 1987, 2, 129-136.##
    [28]    Idowu N. A., “Pore-Scale Modeling: Stochastic Network Generation and Modeling of Rate Effects in Water Flooding,” Ph.D. Thesis, Imperial College London, United Kingdom, 2009.##
    [29]    Mehmani A., Prodanović M., and Javadpour F., “Multiscale, Multiphysics Network Modeling of Shale Matrix Gas Flows,” Transport in Porous Media, 2013, 99, 377-390.##
    [30]    Mehmani A., Tokan-Lawal A., Prodanovic M., and Sheppard A., “The Effect of Microporosity on Transport Properties in Tight Reservoirs,” in SPE North American Unconventional Gas Conference and Exhibition, SPE 144384, 2011.##
    [31]    Rahmanian M., “Pore Level Study of Tight Formations,” M.SC. Thesis, University of Calgary, Canada, 2011.##
    [32]    Kantzas A. and Chatzis I., “Application of the Conjugate Gradients Method in the Simulation of Relative Permeability Properties of Porous Media,” Chemical Engineering Communication, 1988, 69, 169-189.##
    [33]    Kantzas A. and Chatzis I., “Network Simulation of Relative Permeability Curves Using a Bond Correlated-site Percolation Method of Pore Structure,” Chemical Engineering Communication, 1988, 69, 191-214.##
    [34]    Valvatne P. H., “Predictive Pore-scale Modelling of Multiphase Flow,” Ph.D. Thesis, Imperial College London, United Kingdom, 2004.##
    [35]    Al-Dhahli A. R., Geiger S., and van Dijke M. I., “Three-phase Pore-network Modeling for Reservoirs with Arbitrary Wettability,” SPE Journal, 2012, 18, 285-295.##
    [36]    Cluff R. M., Byrnes A. P., Whittaker S., and Krygowski D., “Evidence for a Variable Archie Porosity Exponent ‘m’ and Impact on Saturation Calculations for Mesaverde Tight Gas Sandstones: Piceance, Uinta, Green River, Wind River, and Powder River Basins,” In Proceedings of the AAPG Rocky Mountain Section Meeting, Denver, Colorado, 2008.##
    [37]    Glover P., “What is the Cementation Exponent? A New Interpretation,” The Leading Edge, 2009, 28, 82-85.##
    [38]    Aguilera R., “Flow Units: from Conventional to Tight Gas to Shale Gas Reservoirs,” in the Trinidad and Tobago Energy Resources Conference, Society of Petroleum Engineers SPE 132845, 2010.##
    [39]    Mason G. and Morrow N. R., “Capillary Behavior of a Perfectly Wetting Liquid in Irregular Triangular Tubes,” Journal of Colloid and Interface Science, 1991, 141, 262-274.##
 
    [40]    Ma S., Mason G., and Morrow N. R., “Effect of Contact Angle on Drainage and Imbibition in Regular Polygonal Tubes,” Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1996, 117, 273-291.##
    [41]    Liu X.P., Hu X.X., and Xiao L., “Effects of Pore Structure to Electrical Properties in Tight Gas Reservoirs: An Experimental Study,” presented in the SPE/EAGE European Unconventional Resources Conference and Exhibition held in Vienna SPE 150926, 2012.##
    [42]    Blunt M. J., Personal Communication, 2014.##