Pauline Durand-Riard is working on 3D restoration. Balanced restoration consists of removing the effects of tectonic deformation in order to recover the depositional state of the structural model. Restoration then helps understand a geodynamic scenario, reduce structural uncertainties by testing the consistency of the structural model, and, given a correct rock behavior law, evaluate retrodeformations. An elastic finite element model can be used to solve restoration problems, by setting displacement boundary conditions on the top horizon and contact boundary conditions on the faults cut-offs. This method is generally applied on a tetrahedral mesh, which raises significant meshing problems in complex structural settings, where restoration is precisely most useful. Indeed, the mesh has to be conformal to both faults and horizons, including unconformities and onlap surfaces, which may drastically increase the number of elements and decrease the mesh quality. They propose to embed horizons in the tetrahedral model, and to transfer the associated boundary conditions onto the neighboring nodes of the mesh, using an "implicit" approach. The proposed methods are demonstrated on typical examples and the results show good accordance between both approaches, with a much greater applicability in the implicit case. Moreover, this allows restoring models containing discordances, such as eroded or onlapping surfaces.

Supervisors: Mary Ford (CRPG) and Guillaume Caumon (CRPG-ENSG)