Abstract: Method of heavy oil recovery from deep formations using in-situ wet oxidation steam generation, and a generator for such purpose, comprising a feed for a coal/water slurry and a feed of oxidative gas from ground level to the formation, forming a cavity in the formation where the slurry and gas meet for "wet oxidation" under the inherent pressures and temperature of the deep cavity, augmented by pressurizing the feeds and, if necessary by use of a primary ignitor, to generate carbon dioxide and steam which forces the heavy oil through one or more producing regions located in the formation in the neighborhood of the cavity. Packing may be set in place above the formation to limit escape of productive gas products of the wet oxidation.