Method of producing viscous oil from subterranean formations

Abstract From the Canadian patent

Viscous oil is recovered from a subterranean formation by (a) establishing flow communication between an injection well and a production well in a flow path along the lower portion of a formation pay zone containing the viscous oil, (b) heating the flow path and adjacent portions of the pay zone with hot water or low quality steam, (c) injecting alternating slugs of hot water and steam through the injection well and into the pay zone overlying the heated flow path to cause the oil to liquify and drain into the heated flow path and to be displaced toward the production well, (d) displacing substantially all of the oil in the heated path by hot water and (e), recovering produced fluids …