Mechanistic investigation of bypassed-oil recovery during CO2 injection in matrix and fracture

During CO2 injection in fracture, near-critical tests provided the highest recovery. Significant impact of gravity, swelling and vaporization was inferred from “ultimate recoveries,” “variations of pore pressure,” “the status of oil production,” “recovery rate of corresponding pre-equilibrated test,” and “dimensional analysis.” In CO2 injection in matrix, the maximum recovery was achieved for the first-contact-miscible displacement, as a result of IFT (Interfacial Tension) reduction.