| abstract |
A process for recovering viscous heavy oil from a substantially shallow reservoir having a low temperature and pressure. Following a steam flood, liquid carbon dioxide is injected into the reservoir where said carbon dioxide remains in its liquid state. Afterwards, a spacer volume of a vaporizable drive fluid is injected into the reservoir behind said carbon dioxide. Subsequently, steam injection is commenced which causes the drive fluid to vaporize and the liquid carbon dioxide to gasify. Vaporization of the drive fluid along with gasification of the carbon dioxide causes a pressure increase in the formation allowing the thinned oil to be removed therefrom. |