Hybrid mesh generation for reservoir flow simulation: Extension to highly deformed corner point geometry grids

This paper presents a method to extend the generation algorithm proposed by N. Flandrin [Génération de maillages hybrides pour la simulation de réservoirs pétroliers de nouvelle génération: extension 3D, Ph.D. Thesis, Université de technologie de Troyes, Septembre 2005] in the CPG cases with high levels of deformation, ensuring a fully functional mesh generation for real cases. The main idea is first to construct a mapping between the real space containing the CPG grid along with the radial mesh of the well and a virtual space where the CPG reservoir grid becomes a cartesian grid. Then, in the virtual space, the reservoir grid is deformed at the vinicity of the well in order to restore the circular property of the radial grid. To this end, an optimization technique using mesh refinement procedures is applied. The mapping combined with the above deformation allows us to generate the transition mesh in the virtual space using the algorithm proposed in C. Bennis, W. Sassi [Méthode pour générer un maillage 3D respectant la géométrie d’un corps dans le but de réaliser un modèle représentatif de ce corps, Brevet IFP, numéro d’enregistrement national 96/04.567, Avril 1996]. Finally, coming back to the real space, we obtain the desired hybrid mesh which may require a post processing step to recover its finite volume properties.