Method and system for accessing subterranean deposits from the surface and tools therefor

• US 8,297,377 B2
• Filed: 07/29/2003
• Issued: 10/30/2012
• Est. Priority Date: 11/20/1998
• Status: Expired due to Fees

• Current Assignee: Effective Exploration LLC
• Original Assignee: Vitruvian Exploration, LLC (Vitruvian Exploration II Holdings LLC)
• Inventors: Zupanick, Joseph A.
• Primary Examiner(s): KRECK, JOHN J
• Application Number:
  US10/630,345
• Publication Number:
  US 20040108110A1
• Time in Patent Office: 3,381 Days
• Field of Search: 175/25, 175/48, 175/61, 175/62, 175/65, 175/69, 175/71, 175/72
• US Class Current: 175/61
• CPC Class Codes: B65G 5/00 Storing fluids in natural or artificial cavities or chambers in the earth
• CPC Class Codes: E21B 21/085 Underbalanced techniques, i.e. where borehole fluid pressure is below formation pressure
• CPC Class Codes: E21B 41/0035 Apparatus or methods for multilateral well technology, e.g. for the completion of or workover on wells with one or more lateral branches
• CPC Class Codes: E21B 41/0057 Disposal of a fluid by injection into a subterranean formation
• CPC Class Codes: E21B 43/00 Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells applicable only to water E03B
• 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 43/14 Obtaining from a multiple-zone well
• CPC Class Codes: E21B 43/30 Specific pattern of wells, e.g. optimising the spacing of wells
• CPC Class Codes: E21B 43/305 comprising at least one inclined or horizontal well
• CPC Class Codes: E21B 44/005 Below-ground automatic control systems
• CPC Class Codes: E21B 47/026 of penetrated ground layers
• 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
• CPC Class Codes: G01V 1/48 Processing data

Abstract

According to one embodiment, a system for accessing a subterranean zone from the surface includes a well bore extending from the surface to the subterranean zone, and a well bore pattern connected to the junction and operable to drain fluid from a region of the subterranean zone to the junction.

Claims

1. A method for drilling a well in a coal seam, comprising:

pumping a drilling fluid comprising a liquid down a drill string to a bit drilling a substantially horizontal well bore in a coal seam;

pumping the drilling fluid down the drill string during drilling a plurality of lateral well bores in the coal seam off of the substantially horizontal well bore; and

reducing downhole pressure exerted by the drilling fluid by reducing a weight of drilling fluid in the well bore.

2. The method of claim 1, further comprising reducing down-hole pressure exerted by the drilling fluid by lightening the hydrostatic pressure of the drilling fluid.

3. The method of claim 1, further comprising reducing down-hole pressure exerted by the drilling fluid by aerating the drilling fluid.

4. The method of claim 1, further comprising reducing down-hole pressure exerted by the drilling fluid by circulating compressed air and mixing the air with the drilling fluid.

5. The method of claim 1, further comprising reducing down-hole pressure to nearly zero.

6. The method of claim 1, further comprising reducing down-hole pressure below over balanced conditions.

7. The method of claim 1, further comprising reducing down-hole pressure to approximately 150-200 pounds per square inch.

28. The method of claim 3 wherein pumping a drilling fluid comprising a liquid down a drill string comprises pumping a drilling mud down the drill string.

42. The method of claim 1, further comprising drilling the substantially horizontal well bore through a well bore having a radiused portion.

43. The method of claim 1, wherein the drilling fluid comprises foam.

44. The method of claim 1, further comprising drilling the substantially horizontal well bore through a well bore having a radiused portion.

8. A method of forming a well in a coal seam, comprising:

drilling a well including a horizontal bore and a horizontal drainage pattern extending from the horizontal bore in a coal seam using a drilling fluid comprising liquid; and

reducing the down-hole pressure sufficiently that drilling conditions are not over balanced for drilling of the horizontal bore by reducing a weight of drilling fluid in the well.

9. The method of claim 8, further comprising reducing the down-hole pressure sufficiently that drilling conditions are under balanced for drilling of the horizontal drainage pattern.

10. The method of claim 8, wherein the coal seam is porous and fractured.

29. The method of claim 8 wherein drilling a well including a horizontal bore in a coal seam using a drilling fluid comprising liquid comprises using a drilling mud.

45. The method of claim 8, wherein drilling the horizontal drainage pattern comprises drilling a plurality of lateral well bores in the coal seam off the horizontal well bore.

46. The method of claim 8, further comprising drilling the substantially horizontal bore through a bore having a radiused portion.

47. The method of claim 8, wherein the drilling fluid comprises foam.

48. The method of claim 45, further comprising drilling a substantially horizontal bore through a bore having a radiused portion.

11. A method for producing gas from a coal seam, comprising:

drilling, using a drilling fluid comprising liquid with drilling conditions that are not over balanced, a horizontal drainage pattern extending from a horizontal well bore in a coal seam; and

producing gas collected by the horizontal well bore to the surface.

12. A method for accessing a coal seam from the surface, comprising:

drilling a well bore in a coal seam; and

during drilling, pumping drilling fluid comprising liquid and cuttings from the well bore to the surface;

wherein drilling the well bore comprises drilling a main horizontal bore and a plurality of lateral bores extending from the main horizontal bore.

13. The method of claim 12, whereby hydrostatic pressure on the subterranean zone is reduced during drilling.

14. The method of claim 12, wherein the well bore comprises a first well bore, further comprising pumping drilling fluid and cuttings from the well bore to the surface through a second well bore.

15. The method of claim 14, wherein the second well bore comprises a substantially vertical well bore.

16. The method of claim 14, wherein the first well bore comprises an articulated well bore.

17. The method of claim 12, wherein the coal seam comprises a pressure below 150 pounds per square inch (psi).

18. The method of claim 12, further comprising pumping drilling fluid and cuttings from the well bore to the surface using a downhole pump.

19. The method of claim 12, further comprising pumping drilling fluid and cuttings from the well bore to the surface using gas lift.

20. The method of claim 12, whereby drilling is accomplished without loss of drilling fluids into the subterranean zone and plugging the subterranean zone.

21. The method of claim 14, the first and second well bores intersecting one another at a junction, further comprising pumping drilling fluid and cuttings from proximate to the junction of the first and second well bores to the surface.

22. The method of claim 21, wherein the junction comprises a cavity.

30. The method of claim 12 wherein pumping drilling fluid comprising liquid comprises pumping drilling mud.

23. A method for underbalanced drilling of a coal seam, comprising:

drilling a substantially horizontal well bore in the coal seam;

during drilling of the substantially horizontal well bore in the coal formation, pumping drilling fluid comprising liquid and cuttings from the substantially horizontal well bore to the surface;

drilling a plurality of lateral well bores extending from the substantially horizontal well bore; and

during drilling of the plurality of lateral well bores, pumping drilling fluid comprising liquid and cuttings from the substantially horizontal well bore to the surface.

32. The method of claim 23, whereby hydrostatic pressure on the subterranean zone is reduced during drilling.

33. The method of claim 23, wherein the well bore comprises a first well bore, further comprising pumping drilling fluid and cuttings from the first well bore to the surface through a second well bore.

34. The method of claim 33, wherein the second well bore comprises a substantially vertical well bore.

35. The method of claim 33, wherein the first well bore comprises an articulated well bore.

36. The method of claim 23, wherein the coal seam comprises a pressure below 150 pounds per square inch (psi).

37. The method of claim 23, further comprising pumping drilling fluid and cuttings from the well bore to the surface using a downhole pump.

38. The method of claim 23, further comprising pumping drilling fluid and cuttings from the well bore to the surface using gas lift.

39. The method of claim 23, whereby drilling is accomplished without plugging the coal seam.

40. The method of claim 33, the first and second well bores intersecting one another at a junction, further comprising pumping drilling fluid and cuttings from proximate to the junction of the first and second well bores to the surface.

41. The method of claim 40, wherein the junction comprises a cavity.

24. A method for accessing a subterranean coal formation from the surface, comprising:

drilling a substantially horizontal well bore in the coal formation;

during drilling of the substantially horizontal well bore in the coal formation, reducing the weight of drilling fluids, the drilling fluids comprising liquid;

drilling a plurality of lateral well bores from the substantially horizontal well bore; and

during drilling of the plurality of lateral well bores, lightening hydrostatic pressure exerted by drilling fluids on the coal formation.

25. The method of claim 24, further comprising lightening hydrostatic pressure exerted by the drilling fluids by pumping the drilling fluids from the substantially horizontal well bore to the surface.

26. The method of claim 25, further comprising pumping the drilling fluids using gas lift.

27. The method of claim 25, further comprising pumping drilling fluids from the substantially horizontal well bore to the surface through a second well bore intercepting the substantially horizontal well bore.

31. The method of claim 24 wherein lightening hydrostatic pressure exerted by drilling fluids comprises lightening hydrostatic pressure exerted by drilling mud.

49. The method of claim 24, further comprising drilling the substantially horizontal well bore through a well bore having a radiused portion.

50. The method of claim 24, wherein the drilling fluid comprises foam.

51. The method of claim 24, further comprising drilling the substantially horizontal well bore through a well bore having a radiused portion.

52. A method for accessing a subterranean coal formation from the surface, comprising:

drilling through a well bore having a radiused portion a substantially horizontal well bore in a coal formation;

drilling through the well bore having a radiused portion and the substantially horizontal well bore a plurality of lateral well bores in the coal formation; and

during drilling of the substantially horizontal well bore in the coal formation and the plurality of lateral well bores, using a drilling fluid comprising foam.

53. The method of claim 52, wherein drilling conditions are not overbalanced during drilling of the horizontal well bore and the plurality of lateral well bores.

54. The method of claim 52, further comprising producing gas and water collected by the substantially horizontal well bore and the plurality of lateral well bores to the surface.

55. The method of claim 52, further comprising:

conducting water and gas from the coal formation to a well bore junction, the well bore junction coupled to a fluid collection area at least partially disposed below the substantially horizontal well bore;

collecting water in the fluid collection area from the substantially horizontal well bore and the plurality of lateral well bores for production to the surface;

pumping water from the fluid collection area to the surface; and

producing gas to the surface.

56. A method for drilling a well in a coal seam, comprising:

drilling a substantially horizontal bore in a coal seam using a drilling fluid;

drilling through the substantially horizontal well bore a plurality of lateral well bores in the coal formation; and

lifting drilling fluid to the surface using a pump system having an inlet downhole.

57. The method of claim 56, wherein the inlet of the pump is proximate to the coal seam.

58. The method of claim 57, wherein the inlet of the pump is in the coal seam.