Cavity well system

• US 7,571,771 B2
• Filed: 05/31/2005
• Issued: 08/11/2009
• Est. Priority Date: 05/31/2005
• Status: Expired due to Fees

• Current Assignee: Effective Exploration LLC
• Original Assignee: CDX Gas LLC (EnerVest Ltd.)
• Inventors: Pratt, Christopher A., Seams, Douglas P.
• Primary Examiner(s): Bagnell; David J.
• Assistant Examiner(s): Hutchins; Cathleen R
• Application Number:
  US11/141,335
• Publication Number:
  US 20060266521A1
• Time in Patent Office: 1,533 Days
• Field of Search: 166/50, 166/278, 166/313
• US Class Current: 166/313
• CPC Class Codes: E21B 21/085 Underbalanced techniques, i.e. where borehole fluid pressure is below formation pressure
• CPC Class Codes: E21B 43/006 Production of coal-bed methane E21B43/243 takes precedence
• CPC Class Codes: E21B 43/04 Gravelling of wells
• CPC Class Codes: E21B 43/045 Crossover tools
• CPC Class Codes: E21B 43/121 Lifting well fluids monitoring of down-hole pump systems E21B47/008
• CPC Class Codes: E21B 43/305 comprising at least one inclined or horizontal well

Abstract

A method for accessing a subterranean zone includes forming a subterranean cavity coupled to a land surface and forming a plurality of substantially horizontal bores extending at least partially into the subterranean zone and intersecting the cavity.

Claims

1. A method for accessing a subterranean zone, the method comprising:

forming a first bore extending from a land surface and forming a subterranean cavity in the well bore; and

forming an articulated bore extending from a land surface to proximate the subterranean zone and forming a plurality of substantially horizontal bores from the articulated bore, the plurality of substantially horizontal bores drilled through the cavity and extending at least partially into the subterranean zone.

2. The method of claim 1 wherein forming the cavity comprising forming the cavity proximate the subterranean zone.

9. The method of claim 1 wherein the cavity includes a substantially cylindrical portion.

10. The method of claim 1 wherein forming the first bore comprises forming a substantially vertical bore.

11. The method of claim 1 wherein the articulated bore is offset horizontally from the first bore.

12. The method of claim 1 wherein at least one of the first bore and the articulated bore extends from the land surface through an entry bore.

13. The method of claim 1 further comprising withdrawing fluid from the cavity to the land surface through the first bore.

14. The method of claim 13 wherein withdrawing fluid comprises at least one of providing artificial lift to raise the fluid from the cavity to the land surface and discharging from a flowing well.

15. The method of claim 14 wherein providing artificial lift comprises at least one of pumping the fluid and using a gas lift.

3. A method for accessing a subterranean zone, the method comprising:

forming a first bore extending from a land surface and forming a subterranean cavity in the well bore;

forming an articulated bore extending from a land surface to proximate the subterranean zone and forming a plurality of substantially horizontal bores from the articulated bore, the plurality of substantially horizontal bores drilled through the cavity and extending at least partially into the subterranean zone; and

installing a liner in two or more of the plurality of substantially horizontal bores.

4. The method of claim 3 wherein at least one of the liners terminates proximate the cavity.

5. The method of claim 3 wherein at least one of the liners traverses the cavity.

6. A method for accessing a subterranean zone, the method comprising:

forming a first bore extending from a land surface and forming a subterranean cavity in the well bore;

forming an articulated bore extending from a land surface to proximate the subterranean zone and forming a plurality of substantially horizontal bores from the articulated bore, the plurality of substantially horizontal bores drilled through the cavity and extending at least partially into the subterranean zone; and

gravel-packing at least a portion of the cavity.

7. The method of claim 6 further comprising inserting an apertured liner vertically into the portion of the cavity that has been gravel-packed.

8. The method of claim 7 further comprising radially expanding the liner.

16. A system for accessing a subterranean zone, the system comprising:

a subterranean cavity coupled to a land surface by a first well bore; and

a plurality of substantially horizontal bores drilled from a second well bore through the cavity and extending at least partially into the subterranean zone.

21. The system of claim 16 wherein the cavity comprises a substantially cylindrical portion.

22. The system of claim 16 wherein the second well bore comprises an articulated bore extending from the land surface and coupled to the cavity by the plurality of substantially horizontal bores.

23. The system of claim 22 further comprising a pump inlet in the first bore.

17. A system for accessing a subterranean zone, the system comprising:

a subterranean cavity coupled to a land surface by a first well bore;

a plurality of substantially horizontal bores drilled from a second well bore through the cavity and extending at least partially into the subterranean zone; and

a liner in two or more of the plurality of substantially horizontal bores.

18. The system of claim 17 wherein at least one of the liners terminates proximate the cavity.

19. The system of claim 17 wherein at least one of the liners extends across the cavity.

20. A system for accessing a subterranean zone, the system comprising:

a subterranean cavity coupled to a land surface by a first well bore; and

a plurality of substantially horizontal bores drilled from a second well bore through the cavity and extending at least partially into the subterranean zone;

wherein at least a portion of the cavity is gravel-packed.

24. A method of accessing a coal seam, the method comprising:

forming a cavity proximate the coal seam and coupled to a land surface;

forming a plurality of substantially horizontal bores drilled into and through the cavity and extending at least partially into the coal seam;

gravel-packing at least a portion of the cavity; and

producing fluid from the cavity to the land surface.

25. The method of claim 24 wherein one or more of the plurality of substantially horizontal bores comprises a liner.

26. The method of claim 25 wherein one or more of the liners traverses the cavity.

27. The method of claim 24 wherein producing fluid comprises at least one of providing artificial lift to raise the fluid from the cavity to the land surface and discharging from a flowing well.

28. The method of claim 24 further comprising inserting an apertured liner vertically into the portion of the cavity that has been gravel-packed.

29. The method of claim 28 further comprising radially expanding the apertured liner.

30. A system for accessing a coal seam, the system comprising:

a cavity proximate the coal seam and coupled to a land surface by a first well bore; and

a plurality of drainage bores drilled from a second well bore into the cavity;

wherein at least a portion of the cavity is packed with gravel.

31. The system of claim 30 wherein at least one of the drainage bores comprising a liner adapted to communicate fluid between an interior of the liner and the cavity.