Numerical modeling of stress-dependent permeability

Abstract

In this paper, conceptual models are presented to identify the effects of solid deformation on the changes in rock permeabilities for (a) fractured media, (b) intact media, and (c) fractured porous media subjected to external loads, all in steady state conditions. Finite element schemes are then developed with embedded correlations between induced strain and modified permeability to simulate the coupled flow-deformation behavior of reservior rocks tested in the laboratory. Rock specimen permeability is evaluated through comparison between analytical solution and numerical calculation using 'geometric factors'; the latter simulates the actual laboratory experiment where fluid flow and mechanical loading are applied simultaneously on rock samples. Numerical analyses reveal that physical properties of the porous media, including permeability, are significantly altered by mechanical effects, particularly if the media is naturally fractured.