An Improved CO₂–Oil Minimum Miscibility Pressure Correlation for Live and Dead Crude Oils

Abstract

An improved CO2–oil minimum miscibility pressure (MMP) correlation has been successfully developed to more accurately determine the CO2–oil MMP for a wide range of live and dead crude oils. Experimentally, slim-tube tests have been conducted to determine the CO2–oil MMPs for four crude oil samples with high molecular weights of C7+ fraction. Theoretically, the newly developed CO2–oil MMP correlation is originated from a CO2–oil MMP database from the literature that covers 51 CO2–oil MMP data for various live and dead oil samples, especially those with high C7+ molecular weights. The new CO2–oil MMP correlation is expressed as a function of reservoir temperature, C7+ molecular weight, and mole fraction ratio of volatile components (N2 and CH4) to intermediate components (CO2, H2S, and C2–C6). Compared to nine commonly used CO2–oil MMP correlations in the literature, it is found that the new CO2–oil MMP correlation provides the best reproduction of the literature CO2–oil MMP data with a percentage average absolute deviation (% AAD) of 8.08% and a percentage maximum absolute deviation (% MAD) of 22.99%, respectively. To further examine its predictive capability, the new CO2–oil MMP correlation is then validated with the four experimentally measured CO2–oil MMPs in this study. The newly developed CO2–oil MMP correlation leads to the best prediction accuracy of the four measured CO2–oil MMPs with a % AAD of 4.18% and a % MAD of 7.01%, respectively.