In situ thermal processing of a heavy oil diatomite formation

• US 7,104,319 B2
• Filed: 10/24/2002
• Issued: 09/12/2006
• Est. Priority Date: 10/24/2001
• Status: Expired due to Fees

• Current Assignee: Shell Oil Company (Shell Plc)
• Original Assignee: Shell Oil Company (Shell Plc)
• Inventors: de Rouffignac, Eric Pierre, Karanikas, John Michael, Vinegar, Harold J., Wellington, Scott Lee, Stegemeier, George Leo, Berchenko, Ilya Emil, Maher, Kevin Albert, Shahin, Gordon Thomas Jr.
• Primary Examiner(s): SUCHFIELD, GEORGE A
• Application Number:
  US10/279,293
• Publication Number:
  US 20030173082A1
• Time in Patent Office: 1,419 Days
• Field of Search: 166/50, 166/57, 166/60, 166/245, 166/250.01, 166/250.15, 166/258, 166/272.1, 166/272.2, 166/302, 166/308.1
• US Class Current: 166/245
• CPC Class Codes: E21B 43/243 Combustion in situ

Abstract

An in situ process for treating a diatomite formation is provided. The process may include providing heat from one or more heaters to at least a portion of the formation. The heat may be allowed to transfer from the one or more heaters to a part of the formation such that heat from the one or more heat sources pyrolyzes at least some hydrocarbons within the part. Hydrocarbons may be produced from the formation.

Claims

1. A method for treating hydrocarbons in at least a portion of a diatomite formation, wherein the portion has an average permeability of less than about 10 millidarcy, comprising:

providing heat from heaters to the formation;

allowing the heat to transfer from two or more of the heaters to a selected first section of the formation such that heat from the heaters creates a pyrolysis zone wherein at least some hydrocarbons are pyrolyzed within the first selected section, and allowing the heat to transfer from one or more of the heaters to a selected second section of the formation such that heat from at least one of the heaters heats at least some hydrocarbons in the selected second section to a temperature less than the average temperature in the pyrolysis zone; and

producing a mixture comprising hydrocarbons from the formation.

2. The method of claim 1, wherein at least some heated hydrocarbons in the selected second section flow into the pyrolysis zone.

3. The method of claim 1, wherein the heat decreases the viscosity of at least some of the hydrocarbons in the selected second section.

4. The method of claim 1, further comprising allowing heat to transfer from at least one of the heaters to the selected first section to create thermal fractures in the formation, wherein the thermal fractures substantially increase the permeability of the selected first section.

5. The method of claim 1, further comprising allowing heat to transfer from at least one of the heaters to the selected second section to create thermal fractures in the formation, wherein the thermal fractures substantially increase the permeability of the selected second section.

6. The method of claim 1, wherein the heat is provided such that an average temperature in the selected first section ranges from about 270°

C. to about 375°

C.

7. The method of claim 1, wherein the heat is provided such that an average temperature in the selected second section ranges from about 180°

C. to about 250°

C.

8. The method of claim 1, wherein a viscosity of at least some of the hydrocarbons in the selected second section ranges from about 20 centipoise to about 1000 centipoise.

9. The method of claim 1, wherein at least one of the heaters comprises an electrical heater located in the formation.

10. The method of claim 1, wherein at least one of the heaters is located in one or more heater wells, and wherein at least one of the heater wells comprises a conduit located in the formation, and further comprising heating the conduit by flowing a hot fluid through the conduit.

11. The method of claim 1, further comprising:

monitoring a composition of the produced mixture; and

controlling a pressure in at least the portion of the formation to control the composition of the produced mixture.

12. The method of claim 11, wherein the pressure is controlled by a valve proximate to a location where the mixture is produced.

13. The method of claim 11, wherein the pressure is controlled such that pressure proximate to one or more of the heaters is greater than a pressure proximate to a location where the fluid is produced.

14. The method of claim 1, wherein the pressure in the selected second section is substantially greater than the pressure in the selected first section.

15. The method of claim 1, wherein at least some of the heaters are arranged in a triangular pattern.

16. The method of claim 1, wherein an average distance between heaters in the selected first section is less than an average distance between heaters in the selected second section.

17. The method of claim 1, wherein the heat is provided to the selected first section before heat is provided to the selected second section.

18. The method of claim 1, wherein the selected first section comprises at least one production well.

19. The method of claim 1, wherein an average distance between heaters in the selected first section is between about 2 m and about 10 m.

20. The method of claim 1, wherein an average distance between heaters in the selected second section is between about 5 m and about 20 m.

21. The method of claim 1, wherein the selected first section comprises a planar region.

22. The method of claim 21, wherein at least some of the heaters are arranged in one or more rows, and wherein heaters in at least one of the rows provide heat to the planar region.

23. The method of claim 22, wherein a length of at least one of the rows is between about 75 m and about 125 m.

24. The method of claim 21, wherein the planar region comprises a vertical hydraulic fracture.

25. The method of claim 24, wherein a width of the vertical hydraulic fracture is between about 0.3 cm and about 2.5 cm.

26. The method of claim 24, wherein a length of the vertical hydraulic fracture is between about 75 m and about 125 m.

27. The method of claim 1, wherein at least some of the heaters are arranged in one or more rings, and wherein the heaters in at least one of the rings provide heat to the selected first section.

28. The method of claim 27, wherein the heaters in at least one of the rings provide heat to the selected second section.

29. The method of claim 27, wherein at least one of the rings comprises a polygon.

30. The method of claim 27, wherein at least one of the rings comprises a regular polygon.

31. The method of claim 27, wherein at least one of the rings comprises a hexagon.

32. The method of claim 27, wherein at least one of the rings comprises a triangle.