Feasibility of miscible CO₂ flooding in hydrocarbon reservoirs with different crude oil compositions

Miscible CO₂-based enhanced oil recovery (CO₂-EOR) flooding has been used, on many occasions, to maximize the recovery by mobilizing the residual oil. The success of this method, however, depends highly on the minimum miscibility pressure (MMP), the compatibility of CO₂ with the reservoir rock and fluids. Although there have been several studies on the application of CO₂-EOR, the impact of oil compositions associated with MMP on the feasibility of this technique has not been addressed elsewhere. In this study, a simulation study was carried out to investigate the effect of three different oil compositions on the miscibility and ultimate oil recovery of miscible CO₂-EOR method. The results obtained indicated the oil type does not pose a significant impact on the success of miscible CO₂-EOR. It was also found that the ultimate recovery of oil increases in a short period of time by injecting CO₂ at the miscible conditions at the early stage of natural production. Comparatively, the reservoir with the fluid sample S2 seems to be a suitable choice for the miscible CO₂ flooding once the recovery factor was considered together with the total amount of the fluid injected and produced.