A Modified Dual Porosity Model Considering the Capillary Pressure Difference Between Matrix and Fracture

In fractured reservoirs, the capillary pressure is matrix and is usually much greater than in the fracture. This significant difference of capillary pressure induces an interface effect, where the saturation is discontinuous at the matrix–fracture interface. The conventional transfer function between matrix and fracture in the dual porosity model dose not account for this matrix–fracture interface effect and sometimes leads to results violating the physical principle. To improve the calculation of transfer function, an advanced form is proposed with the consideration of the matrix–fracture interface effect. The proposed form is quite simple and can be directly applied in the engineering application of numerical reservoir simulation and also in commercial software such as ECLIPSE and CMG with little modification. The numerical tests indicate a noticeable improvement of the proposed DP model compared to the conventional one.