Abstract
Study of Minimum Miscibility Composition (MMC) using mixtures of synthesized Liquefied Petroleum Gas (LPG) and Dry Gas (DG) is one of the objectives for Raguba oil field miscibility project. The other essential objective is to determine the Minimum Miscibility Pressure (MMP) of the reservoir oil with CO₂. Preparation of two reservoir oil samples (bubble point pressures ( P_b ) = 1800 psia and 2030 psia) and PVT analyses are accomplished. Based on the PVT data and the LPG/DG mixtures and CO₂ properties, Equation of State (EOS) parameters were preliminary tuned to match the PVT experimental data. Thereafter, the EOS was applied to predict both MMC and MMP. These findings are valuable to design slim tube and swelling experiments. Then, MMC of synthesized LPG/DG solvents with the above two reservoir oil samples was determined experimentally using slim-tube displacement technique. This technique was also applied to determine the CO₂ MMP with oil sample of ( P_b ) = 2030 psia. Cumulative oi recoveries versus pore volume gas injected relations have been used to find out the respective oil recovery at the CO₂ breakthrough. Swelling tests were also carried out on these reservoir oils (P_b = 1800 psia and 2030 psia) by adding mixtures of synthesized LPG and DG solvents at their MMC - 40% LPG and 35% DG respectively. Carbon dioxide (CO₂ - 99.19% pure) was also used to swell the reservoir oil 2035.