The Effect of Small Molecule Gas-Soluble Polymers on Minimum Miscibility Pressure During CO2 Injection

The minimum miscibility pressure is the main technical challenges during CO2 flooding. Therefore, the purpose of this work is to explore the effect of small molecule CO2-soluble polymers including PDMS, PFA, P-1-D, and PVEE on minimum miscibility pressure during gas flooding. The dilute concentrations of polymers (1000 to 50000 ppm) were considered to dissolve in CO2 at 60 and 80 °C. According to the cloud point pressure results, the small molecule CO2-soluble polymers dissolved in carbon dioxide at pressures consistent with gas-based EOR methods (less than 2500 psi) at both 60 and 80 °C. Also, (CO2/polymers)-oil interfacial tensions were decreased extremely via the dissolution of dilute concentrations of polymers in CO2. Moreover, the small molecule CO2-soluble polymers decreased significantly the MMPs by 19.4% for CO2/PFA, 17% for CO2/PDMs, 13.6% for CO2/PVEE, and 10% for CO2/P-1-D scenarios in comparison with pure carbon dioxide injection. Moreover, the 26.5% additional oil was recovered during miscible CO2/PDMS injection in comparison with miscible pure CO2 scenario. Therefore, the small molecule CO2-soluble polymers containing functional groups with oxygen can be one of the best candidates for miscible CO2 displacement in the field-scale.