Anisotropic grid generation for dynamic simulation in heterogeneous hydrocarbon reservoirs

Coarsening from fine geological model to coarse dynamic model is one of the main practical stages in reservoir simulation process in order to minimize simulation run time. In order to preserve accuracy and minimize simulation run time simultaneously, non-uniform element distribution is required to capture dynamic interest and high-flow regions in heterogeneous porous media. In this paper, an automatic coarsening method has been developed to generate anisotropic unstructured mesh with high aspect ratio elements to minimize total number of elements in dynamic model. A high resolution indicator which is called Metric Indicator is generated based on permeability and well effect parameters. Metric Indicator guides the mesh generator to create elements with the desired size, shape and orientation. Single phase gas flow and two-phase gas-water flow equations in a heterogeneous porous media have been solved using Control Volume Finite Approximation (CVFA) method. The comparison between the simulation results of the proposed method in this study and fine-grid model as a reference model demonstrates that the presented method can obtain high accuracy results with the minimum number of elements and the minimum simulation run time.