This paper presents extensive laboratory results of unsteady state displacement of methane by super critical carbon dioxide SCO2 in consolidated reservoir core plugs. The fluid flow of the both phases is presented in terms of relative permeability using explicit methods. The main objective of this study was to investigate the feasibility of SCO2 injection for enhanced gas recovery for a newly discovered gas field situated in the North West Shelf of Western Australia.
The core-flooding experiments of SCO2-methane were carried out on three short plugs and one long vertical sample. The impacts of various parameters were broadly studied on the recovery efficiency and gas multiphase flow at pore scale. These were pressure, temperature, composition, injection-rate, and permeability heterogeneity. Results indicated that the recovery factor at CO2 breakthrough is a function of in situ gas composition, injection rate, and pore pressure. In contrast temperature, absolute permeability and core position factors moderately affected the recovery factor.
A new power model has been developed for interpolating experimental gas-gas relative permeability data. This model can accurately account for subsequent gas compositional changes during the displacement process.