Experiment and correlation of the equilibrium interfacial tension for paraffin + CO2 modified with ethanol

Carbon dioxide enhanced oil recovery (CO 2 EOR) process is widely used in petroleum industry in recent years. But it has some shortcomings, such as early gas breakthrough, fingering, asphaltene precipitations, because of the low viscosity and density of CO 2 . These problems can be resolved by adding some common solvents as chemical modifiers in CO 2 flooding. In this work, ethanol was chosen as the chemical modifier. The effects of ethanol on the equilibrium interfacial tension (IFT) of paraffin   +   CO 2 systems were investigated with different ethanol contents, temperature range 60–100   °C and pressure range 5.06–14.60   MPa, respectively. New correlation for predicting the IFTs of paraffin   +   modified CO 2 systems were proposed based on 150 experimental IFT values. The square of correlation coefficient ( R 2 ), root mean square error ( RMSE ) and average absolute relative deviations ( AARD ) were 0.9948, 0.15 and 2.49%, respectively. The paraffin IFTs for modified CO 2 and pure CO 2 flooding were compared by the IFT average absolute decrease ratio ( AADR ).