Preventing Tetrahedron Inversions during Decompaction-handling 3D Restoration.

Florian Basier and Pauline Durand-Riard. ( 2010 )
in: Proc. 30th Gocad Meeting, Nancy

Abstract

Balanced restoration is a well known method used to test the consistency of a 3D structural model, reduce uncertainty and validate geodynamical interpretations during subsurface studies. After setting displacement boundary and fault contact conditions, 3D restoration may be turned into a geomechanical problem, solved using a finite element method. A problem that occurs while moving tetrahedron, and as a consequence during restoration, is the punctual inversion of tetrahedron, which causes issues in the finite element based computation by altering the topology of the volume. In a previous work, we showed that decompaction can be handled in the 3D restoration process, either on classical structural models, where mesh is conformable to stratigraphic horizons (explicit approach), or on implicit structural models, where surfaces are represented as level sets of a scalar interpolated property (implicit approach). However, the problem of tetrahedron inversion appears much more often on decompacted models, reducing the applicability of coupling restoration and decompaction. We mathematically study the origins of such inversions during decompaction, leading to highlight subvertical reference surfaces and high heterogeneities of the compaction rate to be the two main sources of tetrahedron inversions. Then, we suggest methods to prevent such inversions, in order to dispose of a usable tool to decompact tetrahedral models during restoration. The origin of inversions being the tetrahedral mesh, these methods describe the best predispositions a mesh should have to be decompacted during a restoration process.

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BibTeX Reference

@inproceedings{BasierGM2010,
 abstract = { Balanced restoration is a well known method used to test the consistency of a 3D structural model, reduce uncertainty and validate geodynamical interpretations during subsurface studies. After setting displacement boundary and fault contact conditions, 3D restoration may be turned into a geomechanical problem, solved using a finite element method. A problem that occurs while moving tetrahedron, and as a consequence during restoration, is the punctual inversion of tetrahedron, which causes issues in the finite element based computation by altering the topology of the volume.
In a previous work, we showed that decompaction can be handled in the 3D restoration process, either on classical structural models, where mesh is conformable to stratigraphic horizons (explicit approach), or on implicit structural models, where surfaces are represented as level sets of a scalar interpolated property (implicit approach). However, the problem of tetrahedron inversion appears much more often on decompacted models, reducing the applicability of coupling restoration and decompaction.
We mathematically study the origins of such inversions during decompaction, leading to highlight subvertical reference surfaces and high heterogeneities of the compaction rate to be the two main sources of tetrahedron inversions. Then, we suggest methods to prevent such inversions, in order to dispose of a usable tool to decompact tetrahedral models during restoration. The origin of inversions being the tetrahedral mesh, these methods describe the best predispositions a mesh should have to be decompacted during a restoration process. },
 author = { Basier, Florian AND Durand-Riard, Pauline },
 booktitle = { Proc. 30th Gocad Meeting, Nancy },
 title = { Preventing Tetrahedron Inversions during Decompaction-handling 3D Restoration. },
 year = { 2010 }
}