Mohsen R. Hanna - Tampa FL,
Schlumberger Technology Corporation - Sugar Land TX
166245, 166 50, 166 52, 166261, 1662721, 1662727, 166401
The present invention is a process for recovering oil from an underground oil-containing reservoir. The process includes providing one or more injection wells for injecting a gaseous fluid (steam and air) into the reservoir, the one or more injection wells having a plurality of generally horizontal injector legs, the injector legs positioned within a first depth region in the reservoir. The process further includes providing one or more extraction wells for recovering oil from the reservoir, the one or more extraction wells having plurality of generally horizontal extractor legs, the extractor legs positioned within a second depth region in the reservoir below the first depth region and spaced between the injector legs. Gaseous fluid, typically steam, is injected through the injector legs for a first period of time; and then air is injected through at least one of the injector legs. Alternative embodiments of the invention are also described.