An efficient embedded discrete-fracture model for 2D anisotropic reservoir simulation

Abstract

In this study, we present an embedded discrete fracture model (EDFM) for an in-house reservoir simulator that incorporates the effect of each fracture with arbitrary orientations, lengths and fracture conductivities. Instead of using the linear flow approximation for the EDFM, the interflows between local matrix grids and fracture elements are derived using boundary element method, which considers the effect of local grid geometry and boundary pressure on the flow into the fracture. The implementation is generally compatible with existing finite-difference reservoir simulators, and the accuracy of the EDFM is validated by comparing the results of analytical/semi-analytical models for fracture flow, LGR modules for fracture flow in commercial reservoir simulators and complex fracture flow in discrete fracture network using finite element method. A grid-sensitivity study is conducted to show the convergence of the new method. Moreover, the cases of multiple bi-wing fractures and complex fracture systems are presented to demonstrate the robustness, applicability and computational convenience of the novice approach for simulating the fracture flow in anisotropic reservoir.