The Effect of P-1-D Thickener on CO2 Mobility Control During Enhanced Oil Recovery

The gas mobility control is one of the main challenges during gas injection. It causes early gas break through and decreases the sweep efficiency due to low viscosity. In this study, the small molecule thickener (P-1-D, MW=910 g/mol) was used to improve the CO2 mobility control at reservoir conditions. The small molecule thickener can dissolved in gas without any co-solvent. It leads to the small molecule thickeners which may be used to the EOR field application in comparison with high molecular thickeners. The cloud point pressures were calculated to ensure that the single phase condition has occurred between CO2 and gas thickener. In addition, the effect of gas thickener on CO2 viscosity was investigated for 5000, 10000, 30000, 50000, 80000, and 100000 ppm P-1-D concentrations. Moreover, the impact of P-1-D thickener on interfacial tension (IFT) was studied. The results illustrated that the cloud point pressure for gas and CO2 thickener decreased by increasing in P-1-D concentrations and all of these are below the reservoir pressure. Also, the gas thickener increased the CO2 viscosity 15.7 fold for 80000 ppm concentration which can improve the gas mobility control. Finally, the IFT decreased in presence of the gas thickener which can provide the miscibility condition for at least 10000 ppm concentration.