With increasing energy demands and insignificant addition of oil reserve, CO2 EOR is able to answer the
challenges by increasing 15-20 % more oil recovery. However, oil reservoirs in Indonesia are classified into high
temperature reservoirs that cause high CO2-oil MMP. As a result, CO2 miscible flooding implementation becomes
difficult. Altering composition of CO2 by co-solvent addition in certain concentration is one of the solutions.
By this study, there are two objectives. They are identifying effect of acetone as co-solvent for CO2 in
extracting crude oil through comparative study and performing sensitivity study to find the most favorable acetone
concentration for reducing MMP. Comparative study, used gas chromatography results, had been performed by
comparing results from three cases (without extraction, CO2 extraction, and CO2-acetone mixture extraction) and
then analyzing those effects in crude oil. WINPROP, Computer Modelling Group software, was used for building
M-Fluid phase behaviour and determining CO2-oil MMP through sensitivity study. It was performed by taking
five different acetone concentrations (0 %, 2.5 %, 5 %, 7.5 %, and 10 %) to be determined their MMP value.
From comparative study, acetone assists CO2 in extracting polar, heavy, and straight chain hydrocarbons
because solvent extraction is based on “like dissolves like” or it can be said that polar compounds are soluble in
polar solvent and vice versa. Acetone, a compound which is classified as non associative polar compound, is more
soluble in CO2 than other polar co-solvents. So, it assists to reduce CO2-oil MMP. In the other hand, pure CO2
extracts more light components. Meanwhile from sensitive study, the most favorable acetone concentration is 10
%. MMP of CO2-oil decreases from 1987.53 to 1371.9 psia (decreasing 30.97 % from initial MMP).