Techniques for including large deformations associated with salt and fault motion in basin modeling

Abstract

Modeling large deformations such as non-vertical fault displacement and salt motion have been a major obstacle for the improvement of regional basin modeling studies. Because salt has a large thermal conductivity and is practically impervious, and faults can act as conduits or seals during the evolution of sedimentary basins, they are critical in making accurate predictions of the generation, migration and accumulation of hydrocarbons within salt-bearing basins. To model numerically the evolution of salt structures is not a trivial task and one of the major difficulties in modeling the motion of salt and faults is the management of numerical meshes that are severely corrupted with large deformations. In this study, we use a topological framework for the representation of complex geological structures that makes it possible to model geological processes with large deformation within sedimentary basins and the lithosphere. This framework greatly facilitates the automatic meshing and remeshing required during modeling because meshes, like lithology and physical properties, are treated as attributes of subregions of the model. In this context, we developed a series of techniques to classify fault blocks in order to model the displacement of multiple faults simultaneously in the correct order. In addition, we show that this framework allows the decomposition of the basin model along geological discontinuities and makes it suitable for parallel computation of the solution of differential equations governing generation and migration of hydrocarbons.