Drainage pattern with intersecting wells drilled from surface

• US 6,357,523 B1
• Filed: 11/19/1999
• Issued: 03/19/2002
• Est. Priority Date: 11/20/1998
• Status: Expired due to Term

• Current Assignee: Effective Exploration LLC
• Original Assignee: CDX Gas LLC (EnerVest Ltd.)
• Inventors: Zupanick, Joseph A.
• Primary Examiner(s): Bagnell, David
• Assistant Examiner(s): Kreck, John
• Application Number:
  US09/444,029
• Time in Patent Office: 851 Days
• Field of Search: 166/245, 166/263, 166/50, 166/52, 299/12, 299/2, 299/3, 299/4, 299/5, 299/6, 175/69
• US Class Current: 166/52
• CPC Class Codes: E21B 43/006 Production of coal-bed methane E21B43/243 takes precedence
• CPC Class Codes: E21B 43/13 specially adapted to dewatering of wells of gas producing reservoirs, e.g. methane producing coal beds
• 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

Improved method and system for accessing subterranean deposits from the surface that 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 intersects a horizontal 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 accessing a subterranean zone from the surface, comprising;

a substantially vertical well bore extending from the surface to the subterranean zone;

an articulated well bore extending from the surface to the subterranean zone, the articulated well bore horizontally offset from the substantially vertical well bore at the surface and intercepting the substantially vertical well bore at a junction proximate to the subterranean zone; and

a substantially horizontal drainage pattern extending from the junction into the subterranean zone, wherein the subterranean zone comprises a coal scam.

2. The system of claim 1, the junction further comprising an enlarged cavity formed in the substantially vertical wall bore proximate to the subterranean zone.

3. The system of claim 1, further comprising a substantially vertical rod pumping unit positioned in the substantially vertical well bore and operable to pump fluid drained from the subterranean zone to the junction to the surface.

4. The system of claim 3, wherein the substantially vertical rod pumping unit comprises a sucker rod pump.

5. The system of claim 1, wherein the substantially horizontal drainage pattern comprises:

a diagonal well bore extending from a first end of an area in the subterranean zone to a distant end of the area; and

a plurality of lateral well bores extending in spaced apart relation to each other from the diagonal well bore.

6. The system of claim 5, wherein the lateral well bores progressively shorten as a distance between a respective lateral well bore and the junction increases.

7. The system of claim 1, wherein the substantially horizontal drainage pattern comprises:

a diagonal well bore extending from a first and of an area in the subterranean zone to a distant end of the area;

a first set of lateral well bores extending outwardly from a first side of the diagonal well bore; and

a second set of lateral well bores extending outwardly from a second side of the diagonal well bore.

8. The system of claim 7, wherein a length of each of the first and second sets of lateral well bores progressively shortens as a distance between a respective lateral well bore and the junction increases.

9. The system of claim 7, wherein the lateral well bores of the first and second sets are disposed substantially evenly spaced apart from each other.

10. The system of claim 7, wherein the lateral well bores of the first and second sets each extend substantially at an angle of between 40 and 50 degrees from the diagonal well bore.

11. The system of claim 7, wherein the area substantially comprises a quadrilateral area and the ends comprise distant corners of the quadrilateral area.

12. The system of claim 1, wherein the articulated well bore comprises:

a substantially vertical portion extending downwardly from the surface;

a radiused portion extending from the substantially vertical portion; and

a substantially horizontal portion extending from the radiused portion and intersecting the substantially vertical well bore at the junction.

13. The system of claim 12, wherein the substantially horizontal portion is disposed substantially in a horizontal plane of the subterranean zone.

14. The system of claim 12, wherein the radiused portion is formed having a radius of between 100 and 150 feet.

15. The system of claim 1, further comprising:

an enlarged cavity formed in the substantially vertical well bore at the junction; and

a pump disposed in the enlarged cavity and operable to pump fluid accumulated in the enlarged cavity to the surface.

16. The system of claim 1, wherein the articulated well bore is offset from the substantially vertical well bore at the surface approximately three hundred feet.

17. The system of claim 1, wherein the substantially horizontally drainage pattern comprises a pinnate drainage pattern.

18. The system of claim 1, wherein the pinnate drainage pattern comprises:

a main well bore; and

a plurality of lateral well bores extending outwardly from the main well bore.

19. The system of claim 18, wherein the main well bore is formed sloping upwardly within the subterranean zone.

20. The system of claim 18, wherein the lateral well bores extend from substantially opposite sides of the main well bore and substantially mirror each other on opposite sides of the main well bore.

21. The system of claim 18, wherein each of the lateral well bores comprises:

a radius portion extending from the main well bore; and

an elongated portion extending from the radius portion.

22. The system of claim 18, wherein the main well bore extends from a first and of an area in the subterranean zone to a distant end of the area, and wherein the lateral well bores extend to a periphery of the area.

23. The system of claim 22, wherein the area substantially comprises a quadrilateral area.

24. The system of claim 22, wherein the area substantially comprises a square area.

25. The system of claim 22, wherein the area substantially comprises a rectangular area.

26. The system of claim 1, wherein the substantially horizontal drainage pattern comprises:

a main well bore;

a first set of lateral well bores extending from a first side of the main well bore at a first angle relative to the main well bore; and

a second set of lateral well bores extending from a second side of the main well bore at a second angle relative to the main well bore, the second angle different than the first angle.

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

a substantially vertical well bore extending from the surface to the subterranean zone;

an articulated well bore extending from the surface to the subterranean zone, the articulated well bore horizontally offset from the substantially vertical well bore at the surface and intercepting the substantially vertical well bore at a junction proximate to the subterranean zone; and

a substantially horizontal drainage pattern extending from the junction into the subterranean zone, the substantially horizontal drainage pattern comprising;

a substantially horizontal diagonal well bore extending from the junction defining a first end of an area in the subterranean zone to a distant end of the area;

a first set of substantially horizontal lateral well bores in space relation to each other extending from the diagonal well bore to the periphery of the area on a first side of the diagonal well bore; and

a second set of substantially horizontal lateral well bores in space relation to each other extending from the diagonal well bore to the periphery of the area on a second, opposite side of the diagonal well bore.

28. The system of claim 27, wherein the subterranean zone comprises a coal scam.

29. The system of claim 27, wherein the subterranean zone comprises an oil reservoir.

30. The system of claim 27, wherein the subterranean zone comprises an ultra low pressure reservoir having a pressure below 150 pounds per square inch (psi).

31. The system of claim 27, wherein the lateral well bores each substantially extend at an angle of about 45 degrees from the diagonal well bore.

32. The system of claim 27, wherein the area in the subterranean zone is substantially quadrilateral in shape.

33. The system of claim 27, wherein the area in the subterranean zone in substantially square in shape.

34. The system of claim 27, the junction further comprising an enlarged cavity formed in the substantially vertical well bore proximate to the subterranean zone.

35. The system of claim 27, further comprising a substantially vertical rod pumping unit positioned in the substantially vertical well bore and operable to pump fluid drained from the subterranean zone to the junction to the surface.

36. The system of claim 35, wherein the substantially vertical rod pumping unit comprises a sucker rod pump.

37. The system of claim 27, wherein the diagonal well bore is formed sloping upwardly within the subterranean zone.

38. The system of claim 27, wherein the first and second sets of lateral well bores are disposed in substantially even space relation to each other.

39. The system of claim 27, wherein each of the first set of lateral well bores mirrors one of the second set of lateral well bores on opposite sides of the diagonal well bore.

40. The system of claim 27, wherein the articulated well bore comprises:

a substantially vertical portion extending downwardly from the surface;

a radiused portion extending from the vertical portion; and

a substantially horizontal portion extending from the radiused portion and intersecting the substantially vertical well bore.

41. The system of claim 40, wherein the radiused portion is formed having a radius of between 100 to 150 feet.

42. The system of claim 27, wherein the articulated well bore is offset approximately three hundred feet from the substantially vertical well bore at the surface.

43. The system of claim 27, wherein the first set of lateral well bores extend from the diagonal well bore at a first angle relative to the diagonal well bore, and wherein the second set of lateral well bores extend from the diagonal well bore at a second angle, the first angle different than the second angle.

44. The system of claim 27, wherein each of the lateral well bores of the first and second sets comprises:

a radius portion extending from the diagonal well bore; and

an elongated portion extending from the radiused portion.

45. The system of claim 27, wherein the substantially horizontal diagonal well bore is disposed substantially within a horizontal plane of the subterranean zone.

46. The system of claim 27, the junction further comprising an enlarged cavity formed in the substantially vertical well bore proximate to the subterranean zone, and wherein the substantially vertical well bore extends below the enlarged cavity to form a sump for the enlarged cavity.