Technical Evaluation of Miscible Gas Injection Methods; Case Study in an Iranian Heterogeneous Carbonate Reservoir

The reservoir under study is a reservoir with high amount of H2S and asphaltene. It has more than 1 billion of Original oil in place as static geological model estimated but the problem is the only drive mechanism is Solution gas drive and it has no active aquifer so although it had good flow potential but what if it drops lower than bubble point pressure? Dynamic model showed it was to deplete quickly. By using new reservoir management techniques and enhanced oil recovery in order to pressure maintenance one can recover a lot more oil. The scope of this project was to evaluate in terms of impact of surface facilities, reserves and recovery factor of using gas injection and then different fluid composition for this fieldʹs gas injection (Rich gas corresponding to the associated separator gas to be re-injected to reservoir & Lean gas corresponding to the associated separator gas to be re-injected to reservoir after condensate removal). There are 40 wells in this fields and this was possible to change function of production well to injector if needed. After comprehensive study and technical evaluation it was found that. Miscible gas injection was the best scenario to Natural depletion.