Percolation Effects of Grain Contacts in Partially Saturated Sandstones: Deviations from Archie’s Law
We study the resistivity index of Fontainebleau and Bentheimer sandstones at ambient conditions down to low water saturations both experimentally and numerically. Numerical simulations are in good agreement with experimental measurements of capillary drainage resistivity index by the porous plate method down to water saturations as low as Sw = 10 %. Fontainebleau sandstone exhibits a percolating network of grain contacts, while the higher porosity Bentheimer sandstone does not. We show that this difference in the topological connection of conductive films at low water saturations is responsible for the non-Archie behaviour of Fontainebleau sandstone. Furthermore, it is necessary to attribute a grain contact conductivity to the grain contacts in Fontainebleau sandstone to reconcile experiment and numerical simulation. Conductive films organised as pendular rings around grain contacts are not able to explain this result.
KeywordsPorous media Resistivity index Micro tomography
Unable to display preview. Download preview PDF.
- Archie G.E.: The electrical resistivity log as an aid in determining some reservoir characteristics. Trans. AIME 146, 54 (1942)Google Scholar
- Bohn, R.B., Garboczi, E.J.: User manual for finite element and finite difference programs: a parallel version of NISTIR–6269. Tech. rep., NIST Internal Report 6997 (2003). http://ciks.cbt.nist.gov/~garbocz/nistir6997/
- Durand, C.: Improvement of fluid distribution description during floods by combined use of X-ray CT scan and continuous local resistivity measurements. No. SCA2003-29 in The 17th International Symposium of the Society of Core Analysts, pp. 1–12. Society of Core Analysts, Pau, France (2003)Google Scholar
- Garboczi, E.J.: Finite element and finite difference programs for computing the linear electric and linear elastic properties of digital images of random materials. Tech. rep., NIST Internal Report 6269 (1998). http://ciks.cbt.nist.gov/monograph (Part II, Chapter 2)
- Han, M., Youssef, S., Rosenberg, E., Fleury, M., Levitz, P.: Deviation from Archie’s law in partially saturated porous media: Wetting film versus disconnectedness of the conducting phase. Phys. Rev. E 79(3), 031,127 (2009). doi:10.1103/PhysRevE.79.031127. http://link.aps.org/doi/10.1103/PhysRevE.79.031127 Google Scholar
- Knackstedt, M.A., Arns, C.H., Ghous, A., Sakellariou, A., Senden, T.J., Sheppard, A.P., Sok, R.M., Averdunk, H., Pinczewski, W.V., Padhy, G.S., Ioannidis, M.A.: Pore scale analysis of electrical resistivity in complex core material. In: 21st International Symposium of the Society of Core Analysts,Calgary, Canada vol. 33, pp. 1–12 (2007)Google Scholar
- Kumar M., Sok R., Knackstedt M.A., Latham S., Senden T.J., Sheppard A.P., Varslot T., Arns C.H.: Mapping 3D pore scale fluid distributions: How rock resistivity is influenced by wettability and saturation history. Petrophysics 51(2), 102–117 (2010)Google Scholar
- Makarynsk D., Gurevich B., Ciz R., Arns C.H., Knackstedt M.A.: Finite element modelling of the effective elastic properties of partially saturated rocks. Geophysics 34(6), 647–657 (2008)Google Scholar
- Montaron B.: Connectivity theory: a new approach to modeling non-Archie rocks. Petrophysics 50, 102–115 (2009)Google Scholar
- Rust C.: Electrical resistivity measurements on reservoir rock samples by the two-electrode and four-electrode methods. Petroleum Trans. AIME 195, 217–222 (1952)Google Scholar
- Saadatfar, M., Turner, M.L., Arns, C.H., Averdunk, H., Senden, T.J., Sheppard, A.P., Sok, R.M., Pinczewski, W.V., Kelly, J., Knackstedt, M.A.: Rock fabric and texture from digital core images. 46th annual logging symposium. Society of Petrophysicists & Well Log Analyst, New Orleans, Texas (2005)Google Scholar
- Wilson, O.B.: The influence of porous plates on effective drainage and imbibition rates. Ph.D. thesis, NTNU (2004)Google Scholar