Effect of alcohol-treated CO2 on interfacial tension between CO2 and oil, and oil swelling

Abstract

This paper investigates the extent to which alcohol-treated carbon dioxide (CO2 ), a mixture of alcohol and CO2 equilibrated at experimental pressure and temperature, can lead to greater interfacial tension reduction and greater oil swelling than can pure CO2 . Experimental measurements of interfacial tension and swelling behavior are made using a high-pressure, high-temperature visual cell at 70 °C. Two sets of fluid pairs are used: pure CO2 and oil, and alcohol-treated CO2 and oil. Two types of oil are used: a mixture of 35% hexane and 65% decane (C6 -C10 mixture), and pure decane (pure C10 ). Ethanol and methanol are used to prepare alcohol-treated CO2 . Numerical simulations are used to estimate a reduction in the minimum miscibility pressure when using alcohol-treated CO2 . Interfacial tension between alcohol-treated CO2 and oil is found to be 0.02 to 2.2 mN/m less than that between pure CO2 and oil. Simulation results suggest that alcohol-treated CO2 yields 0.2 to 1.2 MPa lower minimum miscibility pressure compared to pure CO2 . Alcohol-treated CO2 also is found to cause 6% to 43% more swelling of oil than does pure CO2 . Interfacial tension and swelling results suggest that alcohol-treated CO2 yields better miscibility with oil compared to pure CO2 . Cited as: Saira, Yin, H., Le-Hussain, F. Effect of alcohol-treated CO2 on interfacial tension between CO2 and oil, and oil swelling. Advances in Geo-Energy Research, 2021, 5(4): 407-421, doi: 10.46690/ager.2021.04.06

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