Abstract: According to the characteristic of the middle-lower penetrability block reservoir in FZ Oil Field, this article constructs a 3D geologic model through subdividing flow units, studying sedimentary micro-phase and reservoir architecture structure and using RMS random modeling technique. Through reservoir numerical simulation method, it forecasts the distribution rule of the residual oil. Finally it determines the measure of residual oil adjustment for potential seeking and the effect of reducing water cut and improving the recoverable reserves is obvious.