Method for continuously producing viscous hydrocarbons by gravity drainage while injecting heated fluids

Claim 1

A process for mobilizing and recovering normally immobile oil from a tar sand deposit which is penetrated by first and second wells, said first well being used for producing oil and said second well being used for injecting a heated fluid, the process which comprises: (a) completing said first and second wells so that oil, when mobilized, flows substantially separate from said heated fluid; (b) injecting said heated fluid into said second well such that thermal communication is established between said first and second wells; (c) continuing to inject said heated fluid such that said normally immobile oil is heated and drains by gravity to said first well without substantially mixing with said heated fluid, said heated fluid expanding to fill that region of the deposit from which the mobilized oil has drained; and (d) recovering the mobilized oil via said first well.

Claim 5

A method for recovering oil from a tar sand deposit, said oil being essentially immobile at normal reservoir temperatures, comprising: (a) penetrating said deposit with a first well for injecting a heated fluid; (b) penetrating said deposit with a second well for producing fluids, said first and second said wells being constructed and arranged so as to promote the growth of a heated fluid region in said deposit adjacent to said first well of greater than 30,000 ft2 boundary surface area within about 365 days of initiating heated fluid injection; (c) completing said second well so that a predetermined high saturation of oil is maintained adjacent to the lower portion of said second well during production; (d) injecting heated fluid into said first well at a rate calculated to maintain said predetermined saturation and to produce said heated fluid region, said normally immobile oil draining by gravity towards said second well; (e) producing said oil through said second well.

Claim 6

A method for recovering oil from a tar sand deposit, said oil being essentially immobile at normal reservoir temperatures, comprising: (a) penetrating said deposit with a first well for injecting a heated fluid; (b) penetrating said deposit with a second well for producing fluids, said first and second said wells being constructed and arranged so as to promote the growth of a heated fluid region in said deposit adjacent to said first well of greater than 30,000 ft2 boundary surface area within about 365 days of initiating heated fluid injection; (c) completing said second well so that a predetermined high saturation of oil is maintained adjacent to the lower portion of said second well during production; (d) injecting heated fluid into said first well at a rate calculated to maintain said predetermined saturation and to produce said heated fluid region, said normally immobile oil draining by gravity towards said second well; (e) producing said oil through said second well.

Claim 7

A method for recovering normally immobile heavy oil by gravity drainage from a subterranean formation which comprises: (a) penetrating said formation with a production well having a sub-stantially horizontal portion extending a substantial distance through said formation; (b) penetrating said formation with a substantially vertical injection well located approximately above said horizontal portion; (c) completing and operating said production well such that during production the liquid level in said production well is maintained above said horizontal portion; (d) injecting heated fluid into said injection well such that thermal communication is established between said production well and said injection well; (e) continuing the injection of heated fluid such that said heavy oil becomes mobile and drains by gravity to said horizontal portion and such that an expanding heated fluid region is created in said formation adjacent to said injection well without substantial mixing of said heated fluid and said mobilized heavy oil; and (f) producing said mobilized heavy oil through said production well.

Claim 8

A method for recovering normally immobile heavy oil by gravity drainage from a subterranean formation which comprises: (a) penetrating said formation with a production well having a sub-stantially horizontal portion extending a substantial distance through said formation; (b) penetrating said formation with a substantially vertical injection well located approximately above said horizontal portion; (c) completing and operating said production well such that during production the liquid level in said production well is maintained above said horizontal portion; (d) injecting heated fluid into said injection well such that thermal communication is established between said production well and said injection well; (e) continuing the injection of heated fluid such that said heavy oil becomes mobile and drains by gravity to said horizontal portion and such that an expanding heated fluid region is created in said formation adjacent to said injection well without substantial mixing of said heated fluid and said mobilized heavy oil; and (f) producing said mobilized heavy oil through said production well.

Claim 19

A method for recovering viscous hydrocarbons from a subter-ranean formation, said hydrocarbons being substantially immobile at prevailing formation temperatures, the method which comprises: (a) penetrating said formation with an injection well for injecting a heated fluid and a production well for producing hydrocarbons and condensate, said injection and production wells being located along the fracture trend of said formation; (b) completing said wells such that, during production of hydrocarbons, a predetermined relatively high saturation of hydrocarbons can be maintained in the near-well region of said formation adjacent to the lower portion of said production well by regulating production rates; (c) injecting heated fluid into said formation via said injection well at pressures sufficient to fracture said formation, said viscous hydrocarbons being mobilized by said heated fluid and flowing to said production well along with any condensate; (d) producing said mobilized viscous hydrocarbons at rates such that said predetermined saturation of hydrocarbons is established in said near-well region.

Claim 20

A method for recovering viscous hydrocarbons from a subter-ranean formation, said hydrocarbons being substantially immobile at prevailing formation temperatures, the method which comprises: (a) penetrating said formation with an injection well for injecting a heated fluid and a production well for producing hydrocarbons and condensate, said injection and production wells being located along the fracture trend of said formation; (b) completing said wells such that, during production of hydrocarbons, a predetermined relatively high saturation of hydrocarbons can be maintained in the near-well region of said formation adjacent to the lower portion of said production well by regulating production rates; (c) injecting heated fluid into said formation via said injection well at pressures sufficient to fracture said formation, said viscous hydrocarbons being mobilized by said heated fluid and flowing to said production well along with any condensate; (d) producing said mobilized viscous hydrocarbons at rates such that said predetermined saturation of hydrocarbons is established in said near-well region.

Claim 31

A method for recovering viscous hydrocarbons from a subter-ranean reservoir which comprises: (a) penetrating said reservoir with a substantially vertical production well and a substantially vertical injection well, said wells located in line with the fracture trend of said reservoir; (b) completing said production well such that, during production, a predetermined level of hydrocarbons is ensured in the lower portion of said production well; (c) fracturing said reservoir to establish a path of thermal communi-cation between said injection and production wells; (d) injecting steam into said injection well to heat and mobilize said viscous hydrocarbons, said mobilized hydrocarbons draining by gravity to said production well along said thermal communication path and building up to said predetermined level, said predeter-mined level being calculated to promote flow of the mobilized hydrocarbons without substantial mixing with injected steam; (e) producing the mobilized hydrocarbons and steam condensate via said production well so as to maintain said predetermined level of hydrocarbons.

Claim 32

A method for recovering viscous hydrocarbons from a subter-ranean reservoir which comprises: (a) penetrating said reservoir with a substantially vertical production well and a substantially vertical injection well, said wells located in line with the fracture trend of said reservoir; (b) completing said production well such that, during production, a predetermined level of hydrocarbons is ensured in the lower portion of said production well; (c) fracturing said reservoir to establish a path of thermal communi-cation between said injection and production wells; (d) injecting steam into said injection well to heat and mobilize said viscous hydrocarbons, said mobilized hydrocarbons draining by gravity to said production well along said thermal communication path and building up to said predetermined level, said predeter-mined level being calculated to promote flow of the mobilized hydrocarbons without substantial mixing with injected steam; (e) producing the mobilized hydrocarbons and steam condensate via said production well so as to maintain said predetermined level of hydrocarbons.