A new workflow for constrained tetrahedral mesh generation: application to structural models and hex-dominant meshing

in: Proc. 34th Gocad Meeting, Nancy, ASGA

Abstract

This paper introduces workflows to constrain tetrahedral mesh generation in 3D geological domains. The goal is to be able to control the quality of the tetrahedra in order to reduce errors during numerical simulation (Finite-Element and Finite-Volume simulations). Three different input data can be used to constrain the mesh generation. The first possible input is a set of surfaces and lines which can be used to condition the tetrahedral mesh to be conformal to geological structures and well paths. As all the mesh elements from these inputs will be embedded in the generated tetrahedral mesh, we introduce isotropic and anisotropic remeshing methods of triangulated boundary representations of geological structures. The second input is a mesh size used to adapt the tetrahedra edge length according to the local mesh size property. The third input is an orthogonal direction field used to align tetrahedral faces and increase the quality and the number of recombinations of tetrahedra into hexahedra, prisms or pyramids. We use a matching tetrahedra method to build a good quality hex-dominant mesh from this output tetrahedral mesh. These workflows are demonstrated on complex geological models, including discrete fracture networks. These models can be meshed in the Tweedle plugin which embeds Graphite into the Gocad geomodeler.

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BibTeX Reference

@inproceedings{RUNKJRM31,
 abstract = { This paper introduces workflows to constrain tetrahedral mesh generation in 3D geological domains. The goal is to be able to control the quality of the tetrahedra in order to reduce errors during numerical simulation (Finite-Element and Finite-Volume simulations). Three different input data can be used to constrain the mesh generation. The first possible input is a set of surfaces and lines which can be used to condition the tetrahedral mesh to be conformal to geological structures and well paths. As all the mesh elements from these inputs will be embedded in the generated tetrahedral mesh, we introduce isotropic and anisotropic remeshing methods of triangulated boundary representations of geological structures. The second input is a mesh size used to adapt the tetrahedra edge length according to the local mesh size property. The third input is an orthogonal direction field used to align tetrahedral faces and increase the quality and the number of recombinations of tetrahedra into hexahedra, prisms or pyramids. We use a matching tetrahedra method to build a good quality hex-dominant mesh from this output tetrahedral mesh. These workflows are demonstrated on complex geological models, including discrete fracture networks. These models can be meshed in the Tweedle plugin which embeds Graphite into the Gocad geomodeler. },
 author = { Botella, Arnaud AND Levy, Bruno AND Caumon, Guillaume },
 booktitle = { Proc. 34th Gocad Meeting, Nancy },
 publisher = { ASGA },
 title = { A new workflow for constrained tetrahedral mesh generation: application to structural models and hex-dominant meshing },
 year = { 2014 }
}