Numerical study of complex fracture geometries for unconventional gas reservoirs using a discrete fracture-matrix model

Abstract

Unconventional gas reservoirs have become the focus of considerable attention as primary energy resource over the past decades worldwide. Numerical modeling technique plays a critical role in providing the essential tools for evaluating, optimizing and managing the development of such complex systems.In this work, we implement a lower-dimensional discrete fracture and matrix (DFM) model in our previously established multi-continuum numerical simulator (Jiang and Younis, 2015) which incorporates several storage and transport mechanisms for unconventional gas reservoirs. The DFM model is based on unstructured gridding, and could handle the non-ideal geometries of hydraulic fracture in stimulated unconventional formation. Mimetic finite difference (MFD) method is applied to provide a consistent spatial discretization under the unstructured framework.We examine the effects of the irregular fracture pattern with multiple orientations on the production profile of multiple-fractured horizontal well in unconventional gas reservoir. High-fidelity numerical solutions are provided to simulate rate transient from several fracture topologies, and three-dimensional studies are performed for inclined fracture geometry.