Steamflooding has been widely applied as an effective way to improve oil recovery not only in heavy oil reservoirs, but also in light oil reservoirs. It has been investigated that steamflooding is a good way to handle the formation's heterogeneity by decrease the degree of fluid spread and distortion. This reservoir under study is a sandstone member in South Rumaila oil field located in Iraq. This field, with a 58-year production history, has 40 production wells and is surrounded by an infinite active edge water aquifer from the east and the west flanks. Because of some discontinuous series of bitumen at the east flank, the strength of west flank is much effective more than the east one. In this study, a comparative thermodynamic simulation study has been conducted to investigate the feasibility of steamflooding to extract the bitumen and improve oil recovery and determine the optimal future development scenario considering design of experiments and streamline-based simulation results.
First of all, the thermodynamic reservoir simulator (CMG-STARS) has been used to find out the feasibility of steam flooding in the heterogeneous reservoir to extract the bitumen and improve oil recovery. Later, full factorial design (FFD) has been conducted to study the most factors affecting the response (recovery factor) through steamflooding with distinct levels. The factors are steam injection rate, quality, temperature, and number of steam injectors. FFD has shown that the recovery factor is sensitive for all the forgiven factors as well as some interactions and it also shown that the optimal scenario has the lowest steam injection rate and lowest number of injectors to get the highest recovery factor.
The injectors have been selected according to the high connectivity with the producers that has been determined based on the streamline-based simulation results after construction such a connectivity matrix between the injectors and producers. Consequently, a practical optimization approach has been adopted to determine the optimal number of steam injection wells that leads to optimal development scenario. It has shown finally that only one injector, which has higher connections, has led to highest oil recovery.