An approximate cut-cell discretization technique for flow in fractured porous media

Abstract

A new discretization technique for fractured porous media is presented. The most accurate representation for such system is the discrete fracture and matrix (DFM) model where the fractures, their intersections, and the surrounding rock are explicitly represented using a conforming mesh. However, the construction of such meshes becomes challenging for complex systems. The objective of the proposed method is to construct an equivalent DFM model without explicitly constructing a conforming mesh. The method is based on an approximate cut-cell framework where all geometrical quantities needed for discretization are estimated numerically using a local subgrid. The method has built in simplification capabilities and is not very sensitive to the complexity of the model. It is able to generate an equivalent DFM model as well as an embedded discrete fracture model (EDFM). The methodology will be described in detail and illustrated with examples of varying degrees of complexity.