A Topologically-based Framework for Simulating Complex Geological Processes

Earth scientists acquire and interpret a variety of data in an attempt to define the best description of subsurface geological structures, or an earth model, as the data permit. The generation of numerical meshes derived from an earth model is a necessary critical step to provide specific data representations such as finite difference grids or finite element meshes, including the model geometry and associated physical properties for simulation applications. The construction of geological, or earth, models has been a challenge not only due to the scarcity of subsurface data but also because of the geometrical complexity of geological structures. Since typical geological structures (e.g., fractures, faults, salt domes) evolve with time due to various physical processes such as compaction, we use a topological framework to create and maintain earth models that allow the geometry to be modified during simulations and with new interpretations. In this paper we describe a framework used to create a reference model defining a spatial partition, which is used to represent multi-material objects. Multi-resolution and multi-structure meshes can be associated as attributes to each cell of the reference model, making it possible to have a flexible mesh management environment for numerical simulations. Typical applications in geosciences are reservoir simulation, basin-wide heat and fluid transfer, and propagation of seismic waves. Because these applications may require significant computational resources, we use this framework to provide critical adjacency information for the spatial domain decomposition used in parallel computing. Application of these techniques is not restricted to geosciences. They can also be applied to engineering fields that involve large deformations, such as car crash or ballistic simulations. The simulation of complex geological processes such as the evolution of sedimentary basins and multiphase fluid flow within sediments is an important component of the decision-making process in the oil industry. In oil exploration and production, critical decisions are made based on the results of simulations and interpretations of subsurface earth models.