PRODUCING OIL FROM TAR SAND

In a tar sand formation in which a relatively water-impermeable zone overlies a water-permeable zone, tar is recovered by injecting steam into the permeable zone to establish a hot, water-permeable channel between at least one production and at least one injection well, said channel preferably having a tar mobility of at least 15 md/cp; continuing steam injection at a rate sufficient to maintain mobility of the tar in the channel at 15 md/cp and increase the tar mobility in the bulk of the formation to about 15 md/cp, preferably while at about the same time restricting production of fluids from the production well; decreasing the pressure in the formation by increasing production from the production well; and recovering the bitumen from the fluids produced.