Effect of CO2 Concentration in Injecting Gas on Minimum Miscibility Pressure: Compositional Model and Experimental Study

For technical and economic success of miscible gas injection projects, an accurate laboratory measurement of Minimum Miscibility Pressure (MMP) at reservoir conditions is essential. On the other hand, compositional reservoir simulator is a useful tool in gas injection studies and prediction of MMP. The main goal of this paper is to describe a procedure to generate a three phase sequential type of compositional reservoir simulator. The solution method is completely addressed. A compositional thermodynamic program for equilibrium calculation, and pseudo-component determination was developed. Another purpose of this study is to prepare an experimental setup for investigating the effect of CO2 concentration in injecting gas on oil recovery and MMP. Some displacement tests using slim tube apparatus were performed and recoveries and MMPs were measured. Finally, experimental results were compared with the model predictions. A good agreement was achieved between the experimental data and model predictions.