Two-Phase Compositional Flow Simulation in Complex Fractured Media by 3D Unstructured Gridding with Horizontal and Deviated Wells

Abstract

Summary A higher-order numerical model for compositional two-phase flow in fractured media is presented in this paper. The simulation of horizontal and deviated wells is incorporated in the formation using unstructured grids. All commonly used types of finite elements are accounted for in the algorithm: quadrangular and triangular elements in 2D, and hexahedra, prisms and tetrahedra elements in 3D. The fracture crossflow equilibrium (FCFE) approach is applied to model the flow exchange between the fractures and the matrix. FCFE is combined with the hybridized form of the mass conservative mixed finite element (MHFE) and the higher-order discontinuous Galerkin (DG) method. A computer-aided design (CAD) interface is developed that connects the mesh generator to the CAD software. The interface allows to design, mesh, and incorporate horizontal and deviated wells into the higher-order simulator. The algorithm allows flow simulation in fractures in all ranges of permeability values as opposed to the embedded discrete fracture matrix (EDFM) approach where low permeable fractures affect the accuracy of the results. The efficiency, accuracy, and strengths of the model are demonstrated in comparison to alternatives including the embedded discrete fracture approach in different examples. Detailed incorporation of complex wells is presented in this work.