Global approach for calculation of minimum miscibility pressure

Abstract

An algorithm has been developed for calculation of minimum miscibility pressure (MMP) for the displacement of oil by multicomponent gas injection. The algorithm is based on the key tie line identification approach initially addressed by Wang and Orr [Y. Wang and F.M. Orr Jr., Analytical calculation of minimum miscibility pressure, Fluid Phase Equilibria, 139 (1997) 101–124]. In this work a new global approach is introduced. A number of deficiencies of the sequential approach have been eliminated resulting in a robust and highly efficient algorithm. The time consumption for calculation of the MMP in multicomponent displacement processes has been reduced significantly and can now be performed within a few seconds on a PC for a 15-component gas mixture. The algorithm is hence particularly suitable for gas enrichment studies or other case studies where a large number of MMP calculations is required. Predicted results from the key tie line identification approach are shown to be in excellent agreement with slimtube data and with other multicell/slimtube simulators presented in the literature.