Experimental Investigation on CO2 Injection in Block M

The purpose of this report was to perform an experimental evaluation of enhanced oil recovery (EOR) using CO2 injection. A slim tube test and PVT experiment are used to determine the minimum miscibility pressure as well as a few related physical properties. Combined with a long core displacement experiment and nuclear magnetic resonance, CO2 flooding and CO2-water alternate flooding are simulated, and the displacement efficiency of different types of pores is evaluated. The results indicate that the minimum miscibility pressure is 32.6 MPa, and the CO2 flooding is at near-miscible conditions at the current formation pressure. The CO2 solubility of crude oil is large, and the crude oil has a strong expansion ability after the CO2 injection, which is beneficial for improving the recovery of CO2. The EOR of CO2-water alternate flooding is 3.97% higher than that of continuous CO2 flooding, and the EOR in the small and middle pores in the CO2-water alternate flooding is clearly higher. These results will be relevant for the future development of Block M.