Method and system for accessing a subterranean zone from a limited surface area

• US 6,986,388 B2
• Filed: 04/02/2003
• Issued: 01/17/2006
• Est. Priority Date: 01/30/2001
• Status: Expired due to Fees

• Current Assignee: Effective Exploration LLC
• Original Assignee: CDX Gas LLC (EnerVest Ltd.)
• Inventors: Zupanick, Joseph A., Rial, Monty H.
• Primary Examiner(s): Kreck, John
• Application Number:
  US10/406,037
• Publication Number:
  US 20030217842A1
• Time in Patent Office: 1,021 Days
• Field of Search: 166/50, 166/52, 166/313, 166/245
• US Class Current: 166/245
• 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 7/046 horizontal drilling drilling with mechanical conveying means E21B7/003

Abstract

A method and system for accessing subterranean resources from a limited surface area includes a first well bore extending from the surface to the target zone. The first well bore includes an angled portion disposed between the target zone and the surface to provide an offset between a surface location of the first well bore and an intersection of the first well bore with the subterranean resource. The system also includes an articulated well bore extending from the surface to the target zone. The articulated well bore is offset from the first well bore at the surface and intersects the first well bore proximate the target zone. The system further includes a well bore pattern extending from the intersection of the first well bore and the articulated well bore in the target zone to provide access to the target zone.

Claims

1. A system for accessing a target zone from a limited service area, comprising:

a plurality of well bores extending from one or more surface locations to a target zone;

two or more of the well bores each including a well bore junction proximate to the target zone at which the two or more of the well bores intersect other of the plurality of well bores and the two or more of the well bores each including an extended drainage bore; and

wherein a first area bounded by the one or more surface locations is smaller than a second area bounded by the junctions, and wherein the second area is smaller than a third area containing the extended drainage bores.

2. The system of claim 1, wherein the first area is less than approximately 500 square feet.

3. The system of claim 2, wherein the third area is at least approximately 1,000 acres.

4. The system of claim 1, wherein the third area is at least approximately 1,000 acres.

5. The system of claim 1, wherein the two or more well bores each including a well bore junction proximate to the target zone comprise articulated well bores.

6. The system of claim 5, wherein the well bore junctions comprise a cavity.

7. The system of claim 1, wherein the well bore junctions each comprise a cavity.

8. The system of claim 1, wherein the extended drainage bores each comprise a plurality of laterals extending from the extended drainage bore to together form a well bore pattern.

9. The system of claim 8, wherein the well bore pattern comprises a pinnate well bore pattern.

10. The system of claim 1, wherein at least one of the plurality of well bores comprises an angled portion between the surface and the target zone.

27. The system of claim 1, wherein the target zone comprises a coal seam.

11. A system for accessing a subterranean formation from a limited surface area, comprising:

a plurality of diverging well bores extending from a surface, the diverging well bores having a footprint on the surface, the footprint having a first area;

at least one subterranean horizontal drainage pattern coupled to each of the diverging well bores, the diverging well bores extending below the subterranean horizontal drainage pattern;

the first area of the surface footprint being smaller than a second area bounded by the couplings of the subterranean horizontal drainage patterns with the diverging well bores; and

the second area being smaller than a third area bounding the subterranean horizontal drainage patterns.

12. The system of claim 11, further comprising a pumping unit disposed proximate to at least one of the subterranean horizontal drainage patterns and operable to remove resources from the subterranean formation through at least one of the respective plurality of diverging well bores.

13. The system of claim 11, further comprising one or more enlarged cavities each coupled to a subterranean horizontal drainage pattern.

14. The system of claim 11, wherein one or more of the subterranean horizontal drainage patterns comprise a pinnate well bore pattern.

15. The system of claim 11, wherein one or more of the subterranean horizontal drainage patterns comprise a main drainage well bore and a plurality of lateral well bores extending from the main drainage well bore.

16. The system of claim 11, wherein the first area is less than approximately 500 square feet.

17. The system of claim 16, wherein the third area is at least approximately 1000 acres.

18. The system of claim 11, wherein the third area is at least approximately 1000 acres.

28. The system of claim 11, wherein the target zone comprises a coal seam.

19. A method for accessing a subterranean formation from a limited surface area, comprising:

forming a plurality of diverging well bores extending from a surface footprint, the surface footprint having a first area;

forming at least one subterranean horizontal drainage pattern coupled to each of the diverging well bores, the diverging well bores extending below the subterranean horizontal drainage pattern;

the first area of the surface footprint being smaller than a second area bounded by the couplings of the subterranean horizontal drainage patterns with the diverging well bores; and

the second area being smaller than a third area bounding the subterranean horizontal drainage patterns.

20. The method of claim 19, further comprising:

installing a pumping unit disposed proximate to at least one of the subterranean horizontal drainage patterns; and

using the pumping unit to remove resources from the subterranean formation through at least one of the respective plurality of diverging well bores.

21. The method of claim 19, further comprising forming one or more enlarged cavities each coupled to a subterranean horizontal drainage pattern.

22. The method of claim 19, wherein one or more of the subterranean horizontal drainage patterns comprise a pinnate well bore pattern.

23. The method of claim 19, wherein one or more of the subterranean horizontal drainage patterns comprise a main drainage well bore and a plurality of lateral well bores extending from the main drainage well bore.

24. The method of claim 19, wherein the first area is less than approximately 500 square feet.

25. The method of claim 24, wherein the third area is at least approximately 1000 acres.

26. The method of claim 19, wherein the third area is at least approximately 1000 acres.

29. The method of claim 19, wherein the target zone comprises a coal seam.

30. A system for producing gas from a coal seam, comprising:

a surface footprint;

a plurality of well bores coupled to the surface footprint and extending to a coal seams, at least one of the plurality of well bores being slanted;

each well bore connected to a substantially horizontal well bore extending in the coal seam; and

wherein environmental impact is reduced as an area of the surface footprint is smaller than an area containing the substantially horizontal well bores.

31. The system of claim 30, wherein the plurality of well bores coupled to the surface footprint and extending to the coal seam comprise diverging well bores.

32. The system of claim 31, wherein the plurality of diverging well bores extend from disparate surface locations within the surface footprint.

33. The system of claim 31, further comprising:

a plurality of lateral well bores extending from each substantially horizontal well bore to together form a well bore pattern; and

wherein environmental impact is reduced as the area of the surface footprint is smaller than an area containing the well bore patterns.