Minimum Miscibility Pressure by the Vanishing Interfacial Tension Method: Effect of Pressure and Composition by Injection of Gas Cap into Dead/Live Oil

Gas injection is the most commonly used approach in enhanced oil recovery processes in the petroleum industry. Natural gas, nitrogen, and carbon dioxide are the most popular candidates for gas injection. However, gas cap (G.C.) could be another candidate somewhere, which is beneficial and cost-efficient. Therefore, it is essential to investigate and evaluate this kind of gas in the reservoir. Nevertheless, one of the most important key parameters that play an effective role in gas injection economy is the minimum miscibility pressure (MMP). MMP could be calculated with experimental investigations, empirical correlations, and computational methods like slim tube test and vanishing interfacial tension (VIT) or by means of reservoir simulation software such as ECLIPSE. This research is aiming at finding out the MMP of the oil/G.C. system and its mechanism; therefore, it has been attempted to appraise the MMP of the live/dead oil-G.C. system along with its mechanism at a constant reservoir temperature by the VIT technique. The results showed that the extracted MMP for the live oil-G.C. system is more than that for dead oil-G.C., and this value depends upon temperature, pressure, and composition of the system.