Efficient Numerical Simulation Grid System for Massive Bottom Water Reservoir

The scheme of numerical simulation grid directly affects computational accuracy, speed and convergence. For massive bottom water reservoir, there is no stable restraining barrier inside, so gravity differentiation is fully played, so fluid flow vertically in a predominate way. A completely horizontal grid proposed in this paper has two advantages over the conventional bedding grid: (1) It can achieve almost absolute grid uniformity, greatly improve the quality of simulation grid, simulation accuracy of interface and computational speed. (2) Different grid sizes can be set in the longitudinal direction as needed to achieve fine grid in the two-phase flow area and the coarse grid in the bottom water area, so the number of effective grids can be obviously reduced without accuracy lost, and the computational time is shortened by 44% to 67% over the conventional grid system. This study provides a reference for the numerical simulation of similar reservoirs.