Abstract: In a combustion process for recovering hydrocarbons from a subterranean formation vertically traversed by an injection well through which an oxygen-containing gas is injected and a plurality of production wells through which liquid hydrocarbons and gaseous products of combustion are produced; oil recovery is improved by throttling of the production wells to increase the steam pressure in the locus ahead of the combustion zone, and according to a preferred mode, the combustion front advance is controlled by selectively throttling and increasing the gas pressure of production wells in the vicinity of the greatest advance of the combustion front.

Abstract: In a combustion process for recovering hydrocarbons from a subterranean hydrocarbon-bearing formation comprising an upper permeable hydrocarbon-bearing stratum overlying a lower permeable hydrocarbon-bearing stratum and separated therefrom by a semi-permeable stratum which is substantially permeable to oxygen but not substantially permeable to water; the strata are traversed by injection and production wells, the lower hydrocarbon-bearing stratum is ignited near an injection well and oxygen-containing gas is injected into the lower hydrocarbon-bearing stratum to combust hydrocarbons near the injection well and form a combustion front, an oxygen-containing gas is injected into the lower hydrocarbon-bearing stratum and an aqueous fluid is injected into the upper hydrocarbon-bearing stratum to move the combustion front between the injection and the production wells and to prevent or mitigate channeling through the upper hydrocarbon-bearing stratum, and hydrocarbons are recovered from the strata.