(211h) A New Method for Calculating Gas Minimum Miscibility Pressure

Minimum miscibility pressure is a key parameter for the design and operations of successful gas miscible flood project to enhance oil recovery. Operating below the minimum miscibility pressure (MMP) results in immiscible displacement, gas fingering and early breakthrough, and consequently low oil recovery. Operating above the MMP increases project expenses with little or no additional oil recovery.

This paper presents a new method for calculating the MMP taken into consideration the effect of various components of volatile components (C1-N2), intermediate components (C2-C6, H2S), and heavy (C7+). Thus the new method takes into consideration the effect of gas-oil ratio on the MMP.

Accuracy of the proposed method has been compared to statistical correlations and equation of state based methods. The comparison indicates that the new method successfully and accurately predict MMP better than the other published methods. The new methods can be used to estimate MMP for planning miscibility tests, predict miscibility pressure when reliable experimental data is unavailable, and screening oil reservoirs for potential enhanced oil recovery project for specific gas injection.