| abstract |
This invention relates to the recovery of petroleum from tar and heavy oil sands in which one or more injection passages and two or more removal passages are established between the surface of the ground and an underground petroleum deposit. Hot water is injected into the petroleum deposit at a temperature above the pour point temperature of the petroleum substance, and heat is transferred until the petroleum substance becomes flowable. Under the influence of induced pressure, the petroleum substance is made to flow countercurrent to the flow of heat, with the petroleum substance captured at the surface of the ground. |