| This research was directed towards an experimental investigation of the performance of the immiscible carbon dioxide Water-Alternating-Gas (WAG) process, which holds considerable promise for the recovery of moderately viscous heavy oils from thin and/or deep formations, for which reservoir conditions do not favour the application of any of the thermal recovery techniques.; The experimental work was conducted to study the diffusion and gravity segregation phenomena occurring during the process. Work was also done to study the non-isothermal immiscible carbon dioxide WAG process.; A number of measurements were made to study the diffusivity of a gas phase into a liquid phase. In this study, two gases: carbon dioxide and methane were used as the diffusing gas phase. Oils of different physical properties were used to represent the liquid phase. The measurements were made at various pressure and temperature conditions. It was observed that, based on the results obtained, the diffusivity of gaseous carbon dioxide or methane increased with increasing pressure and temperature and decreased with increasing on viscosity and oil molecular weight and that carbon dioxide diffused faster than methane. Using the data collected, an empirical correlation was also developed.; Several displacement experiments were performed to determine the possible application of a carbonated waterflood in place of an immiscible carbon dioxide WAG flood. A carbonated waterflood was found to be inferior to an immiscible carbon dioxide WAG flood, because the carbon dioxide requirement was too high.; Gravity segregation of carbon dioxide and water was investigated by conducting a number of vertical and horizontal displacement experiments. It was observed that gravity segregation affected the displacement efficiency of the immiscible WAG process. As well, it was noted that transverse diffusion of carbon dioxide in the horizontal direction normal to the vertical longitudinal direction helped delay the upward gravity channelling of carbon dioxide.; In addition to the studies mentioned above, a non-equilibrium mathematical model with phase change for the non-isothermal immiscible carbon dioxide WAG process was developed, using non-equilibrium thermodynamics theory. Two sets of scaling criteria for the non-isothermal carbon dioxide process were derived using the mathematical model. These were employed to design and perform non-isothermal experiments.; Moreover, the experimental results obtained in this investigation, as well as those obtained in previous investigations, were correlated using the scaling criteria derived, thus demonstrating the usefulness of the criteria. |
