CO2 miscible displacement process has attracted wide attention of researchers in recent years due to its capacity on enhancing oil recovery. Comparative experimental investigations were carried out for oil recovery characteristics from water/oil pre-saturated porous medium with various displacement fluids of supercritical CO2

supercritical CO2 foam and N2 foam. Referring to the reservoir temperature and pressure conditions

the enhanced oil recovery characteristics are analyzed and discussed in detail based on the displacement pressure drop along the core together with the extracted amount of oil from the porous medium. It is found the supercritical CO2 fluid could achieve obviously higher oil recovery at the condition of 50℃ and 13 MPa. The fact that elevating the system pressure up to 23 MPa couldn't produce extra oil indicates the CO2 displacing oil process achieves miscibility under the condition of 50℃ and 13 MPa in the porous media. The employments of other EOR methods of supercritical CO2 foam and N2 foam didn't produce more oil component from the sample. Compared to the result of 0.8 MPa for N2 foam

the pressure drop for supercritical CO2 foam flooding process is much lower at 0.3 MPa with poorer bubble generation performance. It is expected the experimental results could be employed on screening and evaluating supercritical CO2 flooding technologies.