Comparison and Investigation of Recovery Factor From Simulation of Miscible and Immiscible Gas Injection in One of the Fractured Oil Reservoirs in Iran

A large proportion of the world proven oil has been found in reservoirs rocks that are naturally fractured. Understanding of matrix-fractured interactions, display a unique challenge for enhanced oil recovery. The S Reservoir is a dual porosity fractured reservoir having active aquifer. Because of heterogeneous production zones, total oil recovery was only about 8.04 percent by a total production of 240 MMSTB up to 2008. Production optimization and final recovery increment is the main idea of gas injection in this reservoir. According to Eakin et al.’s empirical correlation, minimum miscibility pressure of 4104 pisa is possible. This pressure is below the average reservoir pressure at 2008. In this study, different injection patterns were investigated. The best injection pattern was selected according to the recovery coefficient. Miscible and immiscible injection scenarios at various rates were compared with natural depletion. The results show that miscible gas injection in this reservoir has more recovery coefficient in comparison with other alternatives.