FraC: A new conforming mesh method for discrete fracture networks

André Fourno (1) , Tri-Dat Ngo (1) , Benoit Noetinger (1) , Christian La Borderie (2)

1 IFPEN - IFP Energies nouvelles
2 SIAME - Laboratoire des Sciences de l'Ingénieur Appliquées à la Mécanique et au génie Electrique

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.

Mots clés: 3D discrete fracture network; Mesh generation; Conforming mesh; Mesh quality; Steady-state single phase flow

Domaines: Ingénierie de l'environnement; Sciences de la Terre

André Fourno, Tri-Dat Ngo, Benoit Noetinger, Christian La Borderie. FraC: A new conforming mesh method for discrete fracture networks. Journal of Computational Physics, 2019, 376, pp.713-732. ⟨10.1016/j.jcp.2018.10.005⟩. ⟨hal-01983436⟩