Method and system for accessing subterranean deposits from the surface

• US 6,964,298 B2
• Filed: 01/20/2004
• Issued: 11/15/2005
• Est. Priority Date: 11/20/1998
• Status: Expired due to Fees

• Current Assignee: Effective Exploration LLC
• Original Assignee: CDX Gas LLC (EnerVest Ltd.)
• Inventors: Zupanick, Joseph A.
• Primary Examiner(s): KRECK, JOHN J
• Application Number:
  US10/761,629
• Publication Number:
  US 20040149432A1
• Time in Patent Office: 665 Days
• Field of Search: 166/245, 166/313, 166/50, 166/52
• US Class Current: 166/50
• CPC Class Codes: E21B 43/006 Production of coal-bed methane E21B43/243 takes precedence
• CPC Class Codes: E21B 43/305 comprising at least one inclined or horizontal well
• CPC Class Codes: E21B 47/09 Locating or determining the position of objects in boreholes or wells , e.g. the position of an extending arm; Identifying the free or blocked portions of pipes
• CPC Class Codes: E21B 7/046 horizontal drilling drilling with mechanical conveying means E21B7/003
• CPC Class Codes: E21F 7/00 Methods or devices for drawing- off gases with or without subsequent use of the gas for any purpose

Abstract

An improved method and system for accessing subterranean deposits from the surface substantially eliminates or reduces the disadvantages and problems associated with previous systems and methods. In particular, the present invention provides an articulated well with a drainage pattern that interests a vertical cavity well. The drainage patterns provide access to a large subterranean area from the surface while the vertical cavity well allows entrained water, hydrocarbons, and other deposits to be efficiently removed and/or produced.

Claims

1. A system for surface production of gas from a subterranean zone, comprising:

a first well bore extending from the surface into the earth;

a second well bore extending from the surface into the earth;

the first and second well bores coupled to each other at a junction in the earth;

a plurality of lateral well bores coupled to the junction and operable to conduct fluids from a subterranean zone to the junction; and

wherein gas may be produced from the subterranean zone to the surface through the first well bore.

2. The system of claim 1, wherein the subterranean zone comprises a coal seam.

3. The system of claim 1, wherein the gas comprises coal bed methane gas.

4. The system of claim 1, wherein the first well bore is substantially vertical.

5. The system of claim 1, wherein the first and second well bores are coupled to each other at a cavity in the earth.

6. The system of claim 1 wherein the plurality of lateral well bores comprises three or more lateral well bores.

7. The system of claim 1, wherein the plurality of lateral well bores comprises four or more lateral well bores.

8. The system of claim 1, wherein the plurality of lateral well bores comprises at least two laterals on each side of a main bore.

9. The system of claim 8, wherein the laterals on at least one side of the main bore progressively shorten in a direction away from at least one of the first and second well bores.

10. The system of claim 1, further comprising a drainage well bore pattern including the plurality of lateral well bores, wherein the drainage well bore pattern comprises a horizontal bore with a plurality of lateral bores extending therefrom.

11. The system of claim 1, wherein the second well bore is slanted or articulated from horizontal.

12. The method of claim 1, further comprising a drainage well bore pattern including the plurality of lateral well bores, wherein the drainage well bore pattern is formed by drilling through the second well bore.

13. The system of claim 1, further comprising a sump formed below the junction.

14. The system of claim 1, further comprising a drainage well bore pattern including the plurality of lateral well bores, wherein the drainage well bore pattern is substantially formed on one side of the junction.

15. The system of claim 1, wherein water may also be produced from the subterranean zone to the surface through at least one of the first or second well bores.

16. The system of claim 15, further comprising a pumping unit operable to remove water from the subterranean zone to the surface through at least one of the first or second well bores.

17. The system of claim 16, wherein the pumping unit comprises an inlet positioned to limit drawing in debris or other material disposed within a sump.

18. The system of claim 16, the pumping unit comprising a rod pumping unit.

19. The system of claim 16, the pumping unit comprising an inlet positioned to limit gas interference.

20. The system of claim 1, further comprising a drainage well bore pattern including the plurality of lateral well bores, wherein the drainage well bore pattern comprises a main bore and a plurality of generally symmetrically arranged lateral bores on each side of the main bore.

21. The system of claim 1, further comprising a drainage well bore pattern including the plurality of lateral well bores, whereby gas and water may be simultaneously produced substantially uniformly from an area of the subterranean zone through the drainage well bore pattern.

22. The system of claim 21, wherein the area of the subterranean zone comprises relatively equal length to width ratios.

23. The system of claim 1, further comprising a drainage well bore pattern including the plurality of lateral well bores, wherein the drainage well bore pattern comprises a substantially horizontal pattern.

24. The system of claim 7, wherein the lateral bores are progressively shorter as they progress away from at least one of the first and second well bores.

25. A system for accessing a subterranean zone from the surface, comprising:

a first well bore extending from the surface to the subterranean zone;

a second well bore extending from the surface to the subterranean zone, the second well bore intersecting the first well bore at a junction proximate the subterranean zone; and

a well bore pattern including a plurality of lateral well bores extending from a main well bore of the pattern, the well bore pattern and connected to the junction and operable to dram fluid from a region of the subterranean zone to the junction.

26. The system of claim 25, wherein the subterranean zone comprises a coal seam.

27. The system of claim 25, wherein gas may be produced from the subterranean zone to the surface through the first well bore.

28. The system of claim 25, wherein the first well bore is substantially vertical.

29. The system of claim 25, wherein the first and second well bores are coupled to each other at a cavity in the earth.

30. The system of claim 25, wherein the drainage well bore pattern comprises two or more laterals.

31. The system of claim 25, wherein the drainage well bore pattern comprises four or more laterals.

32. The system of claim 25, wherein the drainage well bore pattern comprises at least two laterals on each side of the main drainage bore.

33. The system of claim 32, wherein the laterals on at least one side of the main drainage bore progressively shorten in a direction away from at least one of the first and second well bores.

34. The system of claim 25, wherein the drainage well bore pattern comprises a horizontal bore with a plurality of lateral bores extending therefrom.

35. The system of claim 25, wherein the second well bore is slanted or articulated from horizontal.

36. The method of claim 25, wherein the drainage well bore pattern is formed by drilling through the second well bore.

37. The system of claim 25, further comprising a sump formed below the junction.

38. The system of claim 25, wherein the drainage well bore pattern is substantially formed on one side of the junction.

39. The system of claim 27, wherein water may also be produced from the subterranean zone to the surface through at least one of the first or second well bores.

40. The system of claim 39, further comprising a pumping unit operable to remove water from the subterranean zone to the surface through at least one of the first or second well bores.

41. The system of claim 40, wherein the pumping unit comprises an inlet positioned to limit drawing in debris or other material disposed within a sump.

42. The system of claim 40, the pumping unit comprising a rod pumping unit.

43. The system of claim 40, the pumping unit comprising an inlet positioned to limit gas interference.

44. The system of claim 25, wherein the drainage well bore pattern comprises the main bore and a plurality of generally symmetrically arranged lateral bores on each side of the main bore.

45. The system of claim 25, whereby gas and water may be simultaneously produced substantially uniformly from an area of the subterranean zone through the drainage well bore pattern.

46. The system of claim 45, wherein the area of the subterranean zone comprises relatively equal length to width ratios.

47. The system of claim 25, wherein the drainage well bore pattern comprises a substantially horizontal pattern.

48. The system of claim 30, wherein the lateral bores are progressively shorter as they progress away from at least one of the first and second well bores.

49. A method for accessing a subterranean zone from the surface, comprising:

forming a first well bore extending from the surface to the subterranean zone;

forming a second well bore extending from the surface to the subterranean zone, the second well bore intersecting the first well bore at a junction proximate the subterranean zone; and

forming a well bore pattern including a plurality of lateral well bores, the well bore pattern providing drainage of fluids from the subterranean zone to the junction for production to the surface.

50. The method of claim 49, wherein the subterranean zone comprises a coal seam.

51. The method of claim 49, further comprising producing gas from the subterranean zone to the surface through the first well bore.

52. The method of claim 49, wherein the first well bore is substantially vertical.

53. The method of claim 49, wherein the first and second well bores are coupled to each other at a cavity in the earth.

54. The method of claim 49, wherein the drainage well bore pattern comprises two or more laterals.

55. The method of claim 49, wherein the drainage well bore pattern comprises four or more laterals.

56. The method of claim 49, wherein the drainage well bore pattern comprises at least two laterals on each side of a main drainage bore.

57. The method of claim 56, wherein the laterals on at least one side of the main drainage bore progressively shorten in a direction away from at least one of the first and second well bores.

58. The method of claim 49, wherein the drainage well bore pattern comprises a horizontal bore with a plurality of lateral bores extending therefrom.

59. The method of claim 49, wherein the second well bore is slanted or articulated from horizontal.

60. The method of claim 49, further comprising drilling through the second well bore to form the drainage well bore pattern.

61. The method of claim 49, further comprising forming a sump below the junction.

62. The method of claim 49, wherein the drainage well bore pattern is substantially formed on one side of the junction.

63. The method of claim 51, further comprising producing water from the subterranean zone to the surface through at least one of the first or second well bores.

64. The method of claim 63, further comprising operating a pumping unit operable to remove water from the subterranean zone to the surface through at least one of the first or second well bores.

65. The method of claim 64, further comprising positioning an inlet of the pumping unit to limit drawing in debris or other material disposed within a sump.

66. The method of claim 64, the pumping unit comprising a rod pumping unit.

67. The method of claim 64, further comprising positioning an inlet of the pumping unit to limit gas interference.

68. The method of claim 49, wherein the drainage well bore pattern comprises the main bore and a plurality of generally symmetrically arranged lateral bores on each side of a main bore.

69. The method of claim 49, further comprising simultaneously producing gas and water substantially uniformly from an area of the subterranean zone through the drainage well bore pattern.

70. The method of claim 69, wherein the area of the subterranean zone comprises relatively equal length to width ratios.

71. The method of claim 49, wherein the drainage well bore pattern comprises a substantially horizontal pattern.

72. The method of claim 54, wherein the lateral bores are progressively shorter as they progress away from at least one of the first and second well bores.