Investigation and Comparison Between Simulation of Miscible and Immiscible Gas Injection in One of the Undersaturated Fractured Reservoirs in the South of Iran

matrix and fractured interactions present a unique challenge for enhanced oil recovery 1-2. M-Reservoir is dual porosity fractured reservoir having active aquifer. Because of heterogenous production zone, total oil recovery was only 8.4 percent with total production of 240 MMSTB up to 2008. Production optimization and final recovery increment are the main purpose of gas injection in this reservoir. By simulation of slime tube experiment using eclipse 300 software, minimum miscibility pressure of 3700 psia was obtained. This pressure was below the average reservoir pressure at 2008. The study includes analyzing and matching of fluid reservoir, history matching of past reservoir performance and investigating on different location of injected well. The best location of injected well was selected based on the recovery coefficient and injection method of miscible and immiscible at the various rates were compared with natural depletion in selected locations. The result represent the miscible gas injection in this reservoir has more recovery coeeficient rether than natural depletion and there is somewhat recovery coefficient in comparison with immicible gas injection.