SPE Reservoir Evaluation & Engineering
Volume 12, Number 2, April 2009, pp. 297-310

SPE-110455-PA

Stress-Dependent Directional Permeabilities of Two Analog Reservoir Rocks: A Prospective Study on Contribution of µ-Tomography and Pore Network Models

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DOI  More information 10.2118/110455-PA http://dx.doi.org/10.2118/110455-PA

Citation

  • Duatriat, J., Gland, N. Youssef, S., Rosenberg, E., Bekri, S., and Vizika, O. 2009. Stress-Dependent Directional Permeabilities of Two Analog Reservoir Rocks: A Prospective Study on Contribution of µ-Tomography and Pore Network Models. SPE Res Eval & Eng  12 (2): 297-310. SPE-110455-PA.

Discipline Categories

  • 6.8 Fundamental Research in Reservoir Description and Dynamics

Summary

To predict the effects of stress on rock permeability, the authors propose an integrated approach based on an extended rock characterization, an experimental investigation of pressure dependency of directional rock permeabilities and finally a pore-scale simulation of this dependency using equivalent pore network extracted from microtomography analysis. This study has been conducted on two analog reservoir rock types: the high-permeability Bentheimer Sandstone and a dual-porosity bioclastic carbonate, the Estaillades Limestone, having an intermediate permeability. Compression tests have been conducted using a new triaxial cell specially designed to measure directional permeabilities along and transverse to direction of maximum stress application. We measured the pressure dependency of porosity, directional permeabilities, compressibilities, and elastic moduli of the tested samples. We also performed computed microtomography (CMT) imaging of the rock samples, from which we extracted the poral skeletons and the associated characteristics lengths. Then, we calculated the macroscopic transport properties using Pore Network Modeling (PNM) based on the real pore geometry. We included a model of pressure dependence of pore and throat sizes based on pressurized cavity models derived from elasticity theory to simulate the evolution of porosity and permeability with pressure. First, we show that the experimental determination of the evolution of directional permeabilities under hydrostatic and deviatoric loading is feasible. Finally, we show that the PNM coupled with µ tomography can be a promising tool to forecast the evolution of transport properties under stresses representative of reservoir conditions, at the condition of integrating more advanced pore-scale compaction models.

© 2009. Society of Petroleum Engineers

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History

  • Original manuscript received: 2 August 2007
  • Meeting paper published: 11 November 2007
  • Revised manuscript received: 19 June 2008
  • Manuscript approved: 1 September 2008
  • Published online: 15 April 2009
  • Version of record: 15 April 2009