Analysis of Two-phase Fluid Flow through Anisotropic Media Using FEM-Permeability Tensor Transient Model

Abstract

ABSTRACT Reservoir simulators generally employ a simple anisotropy model rather than using a permeability tensor model. However, this can be inaccurate for the fluid-flow calculation in a highly heterogeneous and anisotropic reservoir system having multiple permeability zones. In order to overcome such problems, we have first formulated the two-phase flow equation with permeability tensor, and developed a transient triangular finite element model (FEM) by using Galerkin's method with boundary element method (BEM) as a well model. The developed FEM permeability tensor model coupled with BEM technique for well model has been validated by comparing against the results from HYBOS FDM reservoir simulator. In order to examine the applicability of the developed model, a complex reservoir system having three different permeability zones has been established. As a result, it was found out that the conventional simple anisotropy model neglecting the effect of diagonal permeability yielded serious errors in interpreting the two-phase flow problems.