In situ combustion process for the recovery of liquid carbonaceous fuels from subterranean formations

The in situ combustion process for recovering liquid hydrocarbons from subterranean formations which comprises injecting a stream of combustion air into at least one injection well leading to a combustion zone in said subterranean formation, producing liquid hydrocarbons and combustion gas from at least one production well, separating the liquid hydrocarbons from the stream of combustion gas whereby a separated stream of flue gas is obtained having a heating value between about 15 Btu/scf. (559 kJ/m.sup.3) and about 200 Btu/scf. (7,450 kJ/m.sup.3) and containing at least one aliphatic hydrocarbon having from one to about seven carbon atoms, passing said gas stream admixed with air for combustion in contact with at least one supported platinum oxidation catalyst having palladium incorporated therewith as a cocatalyst in at least one combustion zone at a temperature high enough to initiate and maintain combustion of said gas stream, the total amount of combustion air being sufficient to provide an air equivalence ratio between about 0.20 and about 0.90, expanding the gas stream in a gas turbine following said catalyzed combustion;

• and driving an air compressor with said gas turbine to compress and inject said stream of combustion air into the said subterranean combustion zone.