Abstract: A method for the in-situ recovery of low API gravity oils or bitumen from subterranean hydrocarbon-bearing formations wherein the recovery is optimized by the injection of a mixture of an oxygen-containing gas and steam until the recovery efficiency declines, followed by the injection of a mixture of light hydrocarbon and steam, under operating conditions that may utilize pressurization and drawdown cycles.

Abstract: Viscous petroleum may be recovered from viscous petroleum-containing formations such as tar sand deposits in a process employing steam and air or a free oxygen-containing gas in the ratio of 0.05 to 0.65 M.S.C.F. per bbl. and a cyclical injection-production program in which first steam or steam and air are injected and fluids are produced without restriction until live steam is produced at the production well, after which steam and air are injected and production throttled to a value less than 50% and preferably less than 20% until the formation pressure at the production well rises to a value between about 60% to 95% of the steam injection pressure, after which fluid production is permitted without restriction and steam and air injection is reduced to a value less than 50% and preferably less than 20% of the original injection rate. The process should be applied to a formation in which adequate communication exists or in which a communication path is first established.

Abstract: An improved method for the recovery of heavy oils and bitumen from subterranean formations by the injection thereinto of a mixture of an oxygen-containing gas and steam in which the ratio of free oxygen in the gas to steam is in the range of 0.03 to 0.13 MSCF/bbl.

Abstract: A method for the recovery of low API gravity viscous oils or bitumen from a subterranean formation by the injection of steam followed by a mixture of an oxygen-containing gas and steam until an optimum amount of gas has been injected, followed by injection of steam alone.

Abstract: A method for the recovery of low API gravity viscous oils or bitumen from a subterranean formation by the injection of a mixture of an oxygen-containing gas and steam having an optimum gas/steam ratio that is decreased as the cumulative amount of steam is increased.