An efficient workflow for meshing large scale discrete fracture networks for solving subsurface flow problems

Abstract

A large percentage of subsurface hydrocarbon reservoirs are characterized as very complex due to presence of small to large scale fractures. Modeling of multi-physics processes like, environmental flow, CO2 sequestration, hydrocarbon flows, and so on, through such geologically complex reservoirs is challenging. Main challenges comes from the large scale variation in the fracture scales. Use of traditional modeling approaches, based on dual-porosity/dual permeability medium, to model such complex systems is complicated and results in incorrect flow patterns. Precise and efficient modeling of the fracture networks requires fractures to be represented as lower dimensional objects, which requires an efficient gridding technique. In last decade alone modeling of flow through discrete fracture systems has attracted attention from a number of researchers. As a result few new gridding and discretization techniques have been proposed to model flow through discrete fracture network systems (DFNs). DFN’s usually involve very high or very low angle fracture-fracture intersections and sometime presence of small to very large length scale fracture networks. In this article an efficient workflow for meshing of large scale complex DFN’s networks as lower dimensional objects is presented supported by quantitative results with aim of developing a software tool box, which could be coupled to a subsurface multi-phase flow simulator.