In a miscible gas flooding to heavy oil reservoirs, multiple-contact miscibility between injected gas and reservoir oil can be achieved at pressure greater than a minimum value that is referred to Minimum Miscibility Pressure (MMP). This research includes two parts: first, modification of simplified SAFT (mSSAFT) equation of state is derived to describe vapor-liquid equilibrium calculations and second, prediction of MMP according to forward multiple contact model is done. With respect to objective function, adjustable parameters of SSAFT and mSSAFT were obtained for 21 pure compounds. Comparison of AAD% of the results of mSSAFT, SSAFT and PR EOSs in predicting vapor pressure, liquid density and enthalpy shows that mSSAFT is the most accurate of all. Also, accuracy of these three EOSs for various mixtures has been verified, and the results confirm the reliability of mSSAFT EOS. At last, AAD% of MMP prediction by mentioned EOSs (mSSAFT is 2.20%, SSAFT is 3.25% and PR is 4.13%) proves that Statistical EOSs are more reliable than cubic EOS in modeling MMP.
