Producing heavy oil from tar sands

Abstract From the Canadian patent

Abstract of the Disclosure A method is provided for recovering heavy oil from underground tar sand reservoir by injecting steam into an injection well penetrating the reservoir sufficiently to fracture the tar sand and provide passage for the steam through the tar sand to a production well piercing the tar sand reservoir. Steam is provided at sufficient heat to mobilize heavy oil from the permeated tar sand and at pressure sufficient to maintain competency of the formation to permit continued flow from the injection well to the production well. Injection of surfactant into the tar sand reservoir is used to produce a condensible foam which aids in maintaining back pressure on the injected …