| abstract |
A technique for the in-situ recovery of petroleum hydrocarbons from an underground formation uses a combination of heat and vaporized solvents comprising lighter hydrocarbons. Liquid solvent is injected through a substantially slanted well, placed near the base of the reservoir, and is vaporized in-situ by applying heat through an indirect heating system placed inside the slanted well. Hot solvent vapor rises inside the reservoir, contacts the cold viscous hydrocarbons, condenses, dissolves and diffuses into the hydrocarbon in the reservoir. As a result, the viscous hydrocarbon is diluted to a lower viscosity fluid, which drains to the slanted well and is thereafter produced to the surface. |