Influence of Formation Temperature on Minimum Miscibility Pressure of CO2-Crude Oil System

Abstract

The minimum miscibility pressure (MMP) is the key parameter to determine whether the crude oil is miscible with CO2 in the reservoir. It is found that the formation temperature has a significant influence on the MMP, so it is very important to establish the CO2 MMP prediction correlation with the formation temperature as the main parameter. This correlation is used to explore the influence law of formation temperature on the MMP deeply. Based on the slim tube experiment, 10 representative crude oil samples were selected to conduct experiment to determine the MMP of each sample at different test temperatures. The experimental results of each group were analyzed and the influence of formation temperature on the MMP was summarized, Based on that, a pure CO2 MMP correlation based on Multiple-Linear-Regression modeling (MLR) technique mainly considering the influence of formation temperature is established. The prediction error of correlation is calculated to be 1.71%, which shows appreciable accuracy. Further, separately taking the results of the slim tube experiment and the MMP correlation as the starting point, discuss and analyze the effect of formation temperature on the MMP of CO2-crude oil system. The analysis results show that the formation temperature has a significant positive correlation with the MMP of the CO2-crude oil system within a certain temperature range. It is also found that the results of the experimental analysis of the slim tube experiment are basically consistent with the analysis of the results of the proposed CO2 MMP correlation. Finally, the study of the influence of formation temperature on the MMP of CO2-crude oil system can greatly improve the accuracy and reliability of the MMP prediction of CO2-crude oil system, and provides an important basis for the screening of CO2 flooding blocks in reservoirs.