Experimental and theoretical study of phase behavior for live oil during CO2 EOR process

Carbon dioxide flooding is a very complicated process, involving phase behavior that could increase oil recovery by means of swelling, evaporating, and lowering oil viscosity. The present investigation reports the results of extensive experimental and theoretical work to determine the viscosity and swelling factor changes of the live oil in the Cheshmeh Khoshk reservoir in southern part of Iran (Ilam District), and also minimum miscible pressure is determined. In this study, we want to study the potential of carbon dioxide injection application in improving oil recovery by simulating a slim-tube experiment. In order to get representative fluid samples of a reservoir, it was necessary that the right operation of mixing the separator oil and gas samples to match the bubble point pressure be carried out. The potential application of the study is that we could have a good estimate of the recovery improvement under carbon dioxide gas injection, which will be the basic input parameter for the economic feasibility study, and also a decision can then be made whether to implement or abandon the prospective project.