Thermal drainage process for recovering hot water-swollen oil from a thick tar sand

摘要

Hot liquid-containing water-swollen tar is produced from a tar sand by injecting steam into a well, which is at least initially open and substantially free of obstruction to vertical fluid flow throughout a long vertical interval from the bottom of the tar sand, by producing said liquid from the bottom of the tar sand and maintaining injection and production flow rates that keep the steam temperature above about 450. degree. F. at a pressure high enough to keep the produced liquid substantially free of steam and near to, but less than high enough to damage the reservoir.