High Performance Dual Mesh Method to Simulated Two-phase Gravity Dominated Flows in Porous Media

This paper presents a new combined method for accurate upscaling of two-phase displacements in highly heterogeneous reservoirs. The method has the capability to retain its high performance for various flow regimes, from viscous to gravity dominant displacements, without the need for further modifications and computational steps. Two different grids are incorporated for simulation. The grid on fine scale is used to recognize the complicated physics of flow which depends on dominated driving forces and their interaction with heterogeneity. However, to achieve a fast simulation, the global flow calculation is performed on the coarse scale grid using upscaled equivalent properties. The communication between two different scale grids is achieved by the dual mesh method (DMM) procedure. Since DMM performance is still dependent on the accuracy of the coarse scale simulation, vorticity-based coarse grid generation technique is also incorporated to limit the upscaling errors. The technique optimizes the coarse grid distribution based on vorticity preservation concept where single-phase vorticity is attempted to be preserved among fine and coarse grid models. To demonstrate accuracy and efficiency, the combined DDM-vorticity method is applied to highly heterogeneous systems in two dimensions with and without gravity. The results reveal that the flow regime has only minor impact on the performance of the combined method.