Applications of carbon dioxide for heavy oil enhanced oil recovery via vapour extraction process

Abstract

Recently production of heavy oil and bitumen is become an interesting subject for petroleum engineers to enhance oil recovery from these reservoirs. Vapor extraction (VAPEX) is a promising enhanced oil recovery (EOR) technique that has not been performed in an oil field. Infeasibility of VAPEX process in large scale applications is due mainly to economic issues. Conventional used solvents such as propane and butane in this process are priceless components and utilizing them on a large scale is not considered economical. One attractive option to reduce the process cost is utilizing carbon dioxide (CO2) with the solvents. The high solubility of CO2 in heavy oil provides a higher reduction in oil viscosity. Methodology which has been used in this project is experimental and simulation. By making sandpack and using, different solvent mixtures including propane, methane, and CO2 is tried to investigate the behavior of CO2 as non-condensable carrier gas, co-solvent, and solvent in laboratory condition (ambient temperature and 7 bar). Also all same situation is assumed for simulation by CMG (Computer Modeling Group) In contrast of previous studies, it was found that CO2 is not a good candidate as non-condensable carrier gas for the VAPEX. However, CO2 behavior is similar to propane. Hence, CO2 can be considered as a good alternative for the priceless solvents to extract heavy oil and also the use of CO2 provides substantial environmental benefits.