We are pleased to announce a mini-workshop on geology and meshing, April 1st, 2016.Slice in a 3D mesh of the Corbieres model

New numerical schemes to simulate hydrodynamic, geomechanical and seismological processes have a great potential to handle geometrically complex geological features. Unlocking this potential calls for appropriate meshing algorithms which can adapt to geological heterogeneities while meeting numerical requirements. On the occasion of the PhD defense of Arnaud Botella, this workshop will provide opportunities to discuss about recent advances, trends and challenges in this field. 

You can now watch the PhD defense and the Q&A (in French) of Arnaud Botella



Morning, Salle Gallé, Présidence UL, Campus Brabois (map):


9h30 Jean Virieux (Institut des Sciences de la Terre, Université de Grenoble) Les modes de représentation des milieux pour l'imagerie et pour la modélisation (Medium representations for imaging and modeling)
10h Adrien Loseille (GAMMA 3, INRIA Rocquencourt) Sur un opérateur unique et robuste de modification de maillages et application à la génération de maillages adaptatifs (On a unique and robust operator for mesh editing - Application to adaptive mesh generation)
10h30 BREAK  
10h45 Jean-Francois Remacle (École Polytechnique de Louvain) Fine grain Multi-threaded mesh generation
11h15 Géraldine Pichot (SERENA, INRIA Paris) Problématiques de maillages de réseaux de fractures aléatoire (Meshing random discrete fracture networks)


Afternoon, Amphi G, Ecole Nationale Supérieure de Géologie, Campus Brabois

14h30: PhD defense of Arnaud Botella: Génération de maillages non structurés volumiques de modèles géologicaues pour la simulation de phénomènes physiques (Unstructured volumetric meshing of geological models for physical phenomenon simulations).



In addition to the defense, you may also watch the jury's questions and Arnaud's answers.


Abstract: The main goals of geomodeling are to represent and understand the subsurface. The geological structures have an important role for understanding and predicting its physical behavior.
We defined a geological model as a set of structures and their connections. The meshes are numerical supports to solve the equations modeling the subsurface physics. So it is important to build a mesh representing a geological model to take into account the impact of these structures on the subsurface phenomena.

The objective of this thesis is to develop volumetric meshing methods for geological models. We propose a volumetric unstructured meshing method to build two mesh types: an adaptive tetrahedral mesh and an hex-dominant mesh (i.e. made of tetrahedra, triangular prisms, quadrilateral pyramids and hexahedra). This method generates first a tetrahedral mesh that can respect different types of data:

  1. a geological model defined by its boundaries to capture the structures in the volumetric mesh,
  2. well paths represented as a set of segments,
  3. a mesh size property to control the mesh element edge length
  4. a direction field to control vertex/element alignments inside the mesh to increase some features such as elements with right angles

Then, this tetrahedral mesh can be transformed in a mixed-element mesh. The method recognizes combinatorial relationships between tetrahedra to identify new elements such as prisms, pyramids and hexahedra. This method is then used to generate meshes whose features correspond to a given application in order to reduce errors during numerical computation. Several application domains are considered such as geomechanical, flow and wave propagation simulations.

This PhD was advised by Guillaume Caumon and Bruno Levy

The PhD committee members also included: David Ledez, Adrien Loseille, Géraldine Pichot, Jean-François Remacle, Jean Virieux.