Tetrahedral and hex-dominant meshing for fault damage zones.

in: 35th Gocad Meeting - 2015 RING Meeting, ASGA

Abstract

Faults result from tectonic constraints and are consequences of spatial displacements of geological layers in the sub-surface. They imply deformation on the surrounding rocks in a 3D volume called fault damage zone. Petrophysical properties in this area are altered but most meshing software and geomodelers represent faults as 3D surface objects and do not consider their fault zone. This paper presents a method aiming at representing fault zones while creating unstructured meshes of 3D geological models for numerical simulations. The implemented mesh generation algorithm takes a boundary representation of 3D geological features made of triangulated surfaces. It generates three areas: the fault zone close to the fault with a fine mesh size value, a far zone with the model’s global coarser mesh resolution, and a transition area adapting the mesh size between the two former ones. This method creates homogeneous tetrahedra in the fault zone that can potentially capture complex heterogeneities and non-linear behavior. The presented algorithm is applied on complex models containing multiple folded faults, multiple horizons and a fault intersection. Meshes obtained with two different unstructured meshing methods are given: one tetrahedral mesh and one hex-dominant mesh. The problem of modeling the fault envelope’s shape is also discussed in the paper.

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BibTeX Reference

@INPROCEEDINGS{RenaudeauGM2015,
    author = { Renaudeau, Julien and Botella, Arnaud and Caumon, Guillaume and Levy, Bruno },
     title = { Tetrahedral and hex-dominant meshing for fault damage zones. },
 booktitle = { 35th Gocad Meeting - 2015 RING Meeting },
      year = { 2015 },
 publisher = { ASGA },
  abstract = { Faults result from tectonic constraints and are consequences of spatial displacements of geological layers in the sub-surface. They imply deformation on the surrounding rocks in a 3D volume called fault damage zone. Petrophysical properties in this area are altered but most meshing software and geomodelers represent faults as 3D surface objects and do not consider their fault zone. This paper presents a method aiming at representing fault zones while creating unstructured meshes of 3D geological models for numerical simulations. The implemented mesh generation algorithm takes a boundary representation of 3D geological features made of triangulated surfaces. It generates three areas: the fault zone close to the fault with a fine mesh size value, a far zone with the model’s global coarser mesh resolution, and a transition area adapting the mesh size between the two former ones. This method creates homogeneous tetrahedra in the fault zone that can potentially capture complex heterogeneities and non-linear behavior. The presented algorithm is applied on complex models containing multiple folded faults, multiple horizons and a fault intersection. Meshes obtained with two different unstructured meshing methods are given: one tetrahedral mesh and one hex-dominant mesh. The problem of modeling the fault envelope’s shape is also discussed in the paper. }
}