FraC: A new conforming mesh method for discrete fracture networks

The Fracture Cut (FraC) approach to mesh three-dimensional (3D) Discrete Fracture Networks (DFN) is presented. The considered DFNs consist of a network of planar two-dimensional (2D) fractures sharing intersections that can in turn intersect themselves, resulting in highly complex meshing issues. The key idea of FraC is to decompose each fracture into a set of connected closed contours, with the original intersection traces located at the boundaries of the contours. Thus, intersection segments can be more easily accounted for when building a conforming mesh. Three distinct strategies for intersection points management are also proposed to enhance the quality of resulting meshes. Steady-state single-phase flow simulations are performed to validate the conform meshes obtained using FraC. The results from flow simulations as well as from a mesh quality analysis on a benchmark case show that a flexible AoM strategy (Adding or Moving intersection points) appears to be the best choice to generate ready-to-run meshes for complex DFN. This approach also allows accounting for tiny features within the fracture networks while keeping a good mesh quality and respecting DFN connectivity. Finally, a scalability of the mesh generator is conducted to assess the performance of the approach. (C) 2018 Elsevier Inc. All rights reserved.