Abstract: Shale oil gas is recovered in situ from water-flooded, naturally porous, subterranean oil shale formations by injecting superheated steam under pressure into such formations through injection boreholes extending into the formations. Heat is transferred from the superheated steam to the oil shale, thereby in effect retorting the oil shale and converting the organic (kerogen) content thereof into oil in liquid or vapor form, usually accompanied by some gas. The released shale oil and gas are collected in the water naturally occurring in such a formation and in water resulting from the condensation of the injected steam and are recovered through extraction boreholes by moving both the water and the collected shale oil products to the surface through such boreholes. This is normally effected by pressure of the injected steam, but may be aided, if necessary, by pumping from the extraction boreholes.