Experimental Study on the Sweep Law of CO2 Miscible Flooding in Heterogeneous Reservoir in Jilin

Summary: This study investigates the CO2 displacement efficiency in ultra-low permeability reservoirs. Various development methods, injection procedures, and fracture parameters were tested, showing that permeability, gas-oil ratio, and fracture length significantly impact CO2 displacement efficiency. Changing water drive to gas drive can improve the recovery degree, while fracture location has little effect on CO2 displacement.

Summary: Stable gas gravity drainage is considered an effective method to enhance oil recovery in deep buried, large dip angle, and thick oil reservoirs. Reservoir heterogeneity plays a crucial role in controlling the gas-oil interface and sweep characteristics. The experiment observed for the first time the miscible zone of crude oil and hydrocarbon gas, and the shielding effect of interlayers which can reduce the final oil recovery.