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Abstract

The present invention involves a method and apparatus for enhanced recovery of petroleum fluids from the subsurface by injection of a steam and hydrocarbon vaporized solvent in contact with the oil sand formation and the heavy oil and bitumen in situ. Multiple propped hydraulic fractures are constructed from the well bore into the oil sand formation and filled with a highly permeable proppant. Steam, a hydrocarbon solvent, and a non-condensing diluent gas are injected into the well bore and the propped fractures. The injected gas flows upwards and outwards in the propped fractures contacting the oil sands and in situ bitumen on the vertical faces of the propped fractures. The steam condenses on the cool bitumen and thus heats the bitumen by conduction, while the hydrocarbon solvent vapors diffuse into the bitumen from the vertical faces of the propped fractures. The bitumen softens and flows by gravity to the well bore, exposing fresh surface of bitumen for the process to progressively soften and mobilize the bitumen in a predominantly circumferential, i.e. orthogonal to the propped fracture, diffusion direction at a nearly uniform rate into the oil sand deposit. The produced product of oil and dissolved solvent is pumped to the surface where the solvent can be recycled for further injection.

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First Claim