Rapid Evaluation Model of Enhanced Oil Recovery of CO2 Flooding Based on Modification Fractional Flow Theory

Before a wide range of CO2 enhanced oil recovery (CO2 EOR) technology is implemented for an oilfield, the enhanced oil recovery potential and economy of every reservoir should be evaluated to determine which EOR method is most appropriate. Hundreds of reservoirs in an oilfield exist, and much work should be done. Thus, a rapid and reliable EOR evaluation model is necessary. Combining seepage theory with reservoir simulation, simulation models of CO2 flooding based on fraction theory are proposed in this paper. In the CO2 flooding model, the new minimum miscible pressure evaluation model is introduced to simulate miscible flooding and immiscible flooding, and the relative permeability is modified by the minimum miscible factor. The reduction factor of mobility ratio is introduced to modify the mobility ratio. Interfacial tension calculation formula is introduced to simulate the CO2 displacement mechanism. The simulation model is applied in a low permeability reservoir, and the simulation results show that this model presents certain reliability.