ICCPGE 2016, 1, 25 - 30 Calculation of Minimum Miscibility Pressure for Some Libyan Crude Oils by Using Different Correlations Husin Alhamdi 1,* , Saad Ghareba 2 , Hasan Asharif 3 1 Raslanuf Oil and Gas Processing Company, Raslanuf, Libya 2 Chemical and Petroleum Engineering Department, Al-MergibUniversity, Alkhoms, Libya 3 Chemical Engineering Department, Alzawia University, Alzawia, Libya, * Corresponding Author: husinalhamdi@yahoo.com Abstract Enhanced Oil Recovery (EOR) is defined as “the recovery of oil by injection of a fluid that is not already produced from the reservoir”. There are different methods for the EOR. Among all EOR techniques, the miscible displacement process has the highest potential. It involves the injection of fluids that are capable to generate miscibility with reservoir fluid at certain conditions of pressure and reservoir temperature. The minimum miscibility pressure (MMP ) is defined as the pressure required for the injection fluid to generate a miscible front that is completely miscible with the reservoir fluid. There are many available correlations in literature to calculate the MMP for a given injection and reservoir fluids and reservoir conditions. Choosing the best accurate method of calculating the MMP is very important to determine accurately the MMP value. The objective of this study is to determine the best accurate correlation to determine the MMP for Libyan oils. Six correlations were selected and used to calculate the MMP for different CO 2 -Libyan oil systems. Obtained results were compared to experimental data from literature. Statistical analysis (SPSS Software) was utilized to evaluate the used correlations. Results show that Glaso’s correlation is the most accurate correlation. Furthermore, the available experimental MMP measurements were utilized to develop a new empirical equation to calculate the MMP for CO 2 –Libyan oil systems. Results show that the new correlation can be used for estimation of MMP with better accuracy as compared to other correlations. Keywords: EOR; MMP ; CO 2 ; crude oil; correlations. 1. Introduction Enhanced oil recovery (EOR) is defined as ”the re- covery of oil by injection of a fluid that is not native to the reservoir.” EOR means to extend the pro- ductive life of depleted and uneconomic oil fields. It is usually practiced after recovery by other, less risky and more conventional methods, such as pres- sure depletion (primary recovery) and water flood- ing (secondary recovery). When primary and sec- ondary recoveries start depleting, reservoir should be gone towards the Enhanced Oil recoveries meth- ods. All of currently available EOR is based on one or more of two principles: increasing the capillary number and/or lowering the mobility ratio, com- pared to their water flood values. Increasing the capillary number means, reducing oil-water interfa- cial tension. The mobility ratio may be reduced by increasing water viscosity, reducing oil viscosity, re- ducing water permeability or all of the above. EOR processes are divided into four categories: thermal, gas, chemical, Microbial flooding, miscible. The pro- cesses are typically defined by the nature of their in- jected fluid. For instance, gas EOR includes hydro- carbon miscible/immiscible and carbon dioxide mis- cible and immiscible processes. The miscible process can be carried out by using different methods. These involve injection of miscible hydrocarbon gases as following: 25