Based on the pressure superposition principle and Buckley-Leverett equation,the analytical solution model of 2D two-phase non-piston displacement in five-spot pattern was established.The model was applied to calculate the saturation distribution,displacement front position in the process of displacement.The Buckley-Leverett equation was applied into multidimensional computation in this paper.The analytic solution was given for 2D two-phase flow problem.Through comparing the analytic results with the Eclipse...