Evaluation of the impact of strain-dependent permeability on reservoir productivity using iterative coupled reservoir geomechanical modeling

Abstract

Permeability an important property plays a key role in reservoir performance, numerical reservoir simulation, drilling and production planning. In such reservoirs, stress and strain alters induced by extraction and injection of fluid may substantially change permeability in an irreversible manner. With regard to this phenomenon, several reservoirs may require to consider straindependent permeability, in order to have an accurate performance. In such reservoirs, especially carbonate reservoirs which are a significant proportion of the world’s hydrocarbon reserves, to present the mechanical behavior of rocks, the cap elastoplastic model is may be required. Therefore, the goal of this paper is to evaluate the strain-dependent permeability using coupled reservoir geomechanical modeling with considering the cap elastoplastic model. This coupling is implemented using a fixed stress iterative coupled scheme. In this coupling, the governing equation for fluid is presented by Darcy’s law in which the permeability is nonlinear. The geomechanical module is analyzed using Biot’s theory and cap elastoplastic model. To indicate the mechanical behavior of reservoir rock, the DiMaggio-Sandler elastoplastic model which is a cap envelope is selected. The numerical approximation is done by employing mixed finite element for reservoir module and a continuous Galerkin finite element for geomechanics. Several numerical simulations are performed to verify the models and analyze the effect of strain-dependent permeability on reservoir productivity.