COMBINED STEAM AND VAPOR EXTRACTION PROCESS (SAVEX) FOR IN SITU BITUMEN AND HEAVY OIL PRODUCTION

摘要

A process for recovery of hydrocarbons from an underground reservoir of said hydrocarbons the underground reservoir being penetrated by an injection well and a production well spaced from the injection well, the process comprising: (a) injecting steam into said reservoir thereby heating said reservoir to mobilize and recover at least a fraction of said hydrocarbons and to form a chamber in said reservoir; and then, (b) continuing to inject steam into said reservoir and mobilize and recover hydrocarbons therefrom until at least one of (i) an upper surface of said chamber has progressed vertically to a position that is approximately 25 to 75%, preferably 40 to 60%, or about 50% the distance from the injection well to the top of the reservoir, and (ii) the recovery rate of said hydrocarbons is approximately 25 to 75%, preferably 40 to 60%, or about 50% of the peak predicted recovery rate using steam-assisted gravity drainage; and (c) injecting a solvent of at least a fraction of said hydrocarbons, said solvent being capable of existing in vapor form in said chamber and being just below said solvent's saturation pressure in said chamber thereby mobilizing and recovering a subfraction of said fraction of said hydrocarbons.