Abstract
In this investigation, Peng-Robinson equation of state (EOS) modeling for two recombined reservoir oil samples is represented using the Computer Modelling Group (CMG PROP) software. EOS characterizations for these oils were developed to predict optimum solvent compositions—minimum miscibility composition (MMC) for LPG-Dry Gas mixtures, and minimum miscibility pressure (MMP) for CO2 in miscible flooding. EOS parameters were tuned to match the experimental PVT data besides viscosity data for both oils. Accordingly, phase diagrams, pseudoternary diagrams, and pressure-composition diagrams for both oils in contact with several LPG-Dry Gas compositions and/or CO2 were generated at a reservoir temperature of 206ºF. It was found that the main mechanism of oil recovery is a condensing drive for both oils at minimum miscibility composition. Miscibility of these oils with CO2 was achieved at a pressure considerably high. These findings were used to help design slim tube experiments as well as swelling experiments.