A rigid element method for building structural reservoir models

Most current approaches for building structural reservoir models focus on geometrical aspects and consistency with seismic and well data. Few approaches account for the validity of 3D geological models regarding structural compatibility. It may be done using restoration to check the kinematics or mechanics. This is generally performed a posteriori, which also provides critical insights on the basin/reservoir history, but requires significant modeling efforts. This paper presents an approach introducing a first-order kinematic and mechanical consistency at the early stages of the structural modeling. Because the full deformation path is generally poorly constrained, we suggest using simplified approaches to generate plausible structures and assess first-order deformations, making efficiency and robustness more important than physical accuracy. A mechanical deformable model based on rigid elements linked by a non-linear energy has been adapted to geological problems. The optimal deformation is obtained by minimizing the total energy with appropriate boundary conditions. Last, the displacement field is transferred to the geological objects embedded into the rigid elements. With this approach, 3D structural models can be obtained by successively modeling the tectonic events. The underlying tectonic history of resulting models is explicitly controlled by the interpreter and can be used to study structural uncertainties.