Method and apparatus for recovering viscous petroleum from tar sand

Claim 1

A method of recovering petroleum from subterranean viscous petroleum tar sands comprising drilling an injection well whose drill path is deviated from the perpendicular, and extends for a major portion of its length into said subterranean viscous petroleum tar sand, inserting casing within said injection well to at least a point just beyond a site determined to be a terminal injection point, perforating said casing at selected locations, running into the bore of said perforated casing a dual tubing string providing a circulation path for the use of through the flowline service tools, at least one of said dual tubing strings having a plurality of spaced apart side pocket mandrels, providing means for packing off the tubing casing annulus situated between the uppermost side pocket mandrel and the surface of the well, providing means in said side pocket mandrels for regulating the flow of fluids from the bore of the tubing to the outside thereof, drilling and completing a plurality of production wells into said subterranean viscous petroleum tar sands positioned above and along the length of said injection well, circulating a heated fluid through said injection well, said heated fluid flowing through said flow regulator means into said subterranean viscous petroleum tar sands to reduce the viscosity of the petroleum contained therein, and recovering said reduced viscosity petroleum by said production wells.

Claim 2

A method of recovering petroleum from subterranean viscous petroleum tar sands comprising drilling an injection well whose drill path is deviated from the perpendicular, and extends for a major portion of its length into said subterranean viscous petroleum tar sand, inserting casing within said injection well to at least a point just beyond a site determined to be a terminal injection point, perforating said casing at selected locations, running into the bore of said perforated casing a dual tubing string providing a circulation path for the use of through the flowline service tools, at least one of said dual tubing strings having a plurality of spaced apart side pocket mandrels, providing means for packing off the tubing casing annulus situated between the uppermost side pocket mandrel and the surface of the well, providing means in said side pocket mandrels for regulating the flow of fluids from the bore of the tubing to the outside thereof, drilling and completing a plurality of production wells into said subterranean viscous petroleum tar sands positioned above and along the length of said injection well, circulating a heated fluid through said injection well, said heated fluid flowing through said flow regulator means into said subterranean viscous petroleum tar sands to reduce the viscosity of the petroleum contained therein, and recovering said reduced viscosity petroleum by said production wells.

Claim 9

A system for recovering petroleum from subterranean viscous petroleum tar sands comprising: at least one injection well which is deviated from the perpendicular and extends for at least a portion of its length into said subterranean viscous petroleum tar sand, said injection well having disposed therein: a casing lining said well, and being perforated at at least one site therein, a dual tubing string disposed within said casing providing a circulation path for the use of through the flowline service tools, at least one of said dual tubing strings having a plurality of spaced apart side pocket mandrels, with means therein for regulating the flow of fluids from the bore of said tubing to the outside thereof, means for packing off the tubing casing annulus situated between the uppermost side pocket mandrel and the surface of the well, and at least one production well extending from the surface into said subterranean viscous petroleum tar sands positioned above and along the length of said injection well, whereby a heated fluid circulated through said injection well exits said well through said flow regulator means into said subterranean viscous petroleum tar sands to reduce the viscosity of the petroleum contained therein, which is recovered through said production well.

Claim 10

A system for recovering petroleum from subterranean viscous petroleum tar sands comprising: at least one injection well which is deviated from the perpendicular and extends for at least a portion of its length into said subterranean viscous petroleum tar sand, said injection well having disposed therein: a casing lining said well, and being perforated at at least one site therein, a dual tubing string disposed within said casing providing a circulation path for the use of through the flowline service tools, at least one of said dual tubing strings having a plurality of spaced apart side pocket mandrels, with means therein for regulating the flow of fluids from the bore of said tubing to the outside thereof, means for packing off the tubing casing annulus situated between the uppermost side pocket mandrel and the surface of the well, and at least one production well extending from the surface into said subterranean viscous petroleum tar sands positioned above and along the length of said injection well, whereby a heated fluid circulated through said injection well exits said well through said flow regulator means into said subterranean viscous petroleum tar sands to reduce the viscosity of the petroleum contained therein, which is recovered through said production well.