Undulating well bore

• US 6,708,764 B2
• Filed: 07/12/2002
• Issued: 03/23/2004
• Est. Priority Date: 07/12/2002
• 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:
  US10/194,366
• Publication Number:
  US 20040007351A1
• Time in Patent Office: 620 Days
• Field of Search: 166/313, 166/50, 166/52, 166/245, 175/61, 175/62
• US Class Current: 166/313
• CPC Class Codes: E21B 41/0064 Carbon dioxide sequestration storing fluids in porous layers B65G5/005
• 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
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

In accordance with one embodiment of the present invention, a subterranean drainage pattern for accessing a subterranean zone includes at least one undulating well bore. The undulating well bore includes at least one inclining portion drilled through the subterranean zone at an inclination sloping toward an upper boundary of the single layer of subterranean deposits and at least one declining portion drilled through the subterranean zone at a declination sloping toward a lower boundary of the single layer of subterranean deposits. At least one bending portion couples the at least one inclining portion and the at least one declining portion to form a waveform.

Claims

1. A subterranean drainage pattern for accessing an area of a subterranean zone comprising at least one undulating well bore, the undulating well bore confined within a single layer of subterranean deposits and comprising:

at least one inclining portion drilled through the subterranean zone at an inclination sloping toward an upper boundary of the single layer of subterranean deposits;

at least one declining portion drilled through the subterranean zone at a declination sloping toward a lower boundary of the single layer of subterranean deposits; and

at least one bending portion coupling the at least one inclining portion and the at least one declining portion to form a waveform;

wherein the drainage pattern comprises a plurality of waveforms varying over space in a substantially periodic manner.

2. The subterranean drainage pattern of claim 1, wherein the single layer comprises hydrocarbons.

3. The subterranean drainage pattern of claim 2, wherein the single layer comprises a coal seam.

4. The subterranean drainage pattern of claim 1, wherein the wavelength of each waveform is greater than six hundred feet.

5. The subterranean drainage pattern of claim 1, wherein the drainage pattern comprises a plurality of waveforms, the waveforms having substantially equal wave heights.

6. The subterranean drainage pattern of claim 5, wherein the wave height of each waveform is greater than ten feet.

7. The subterranean drainage pattern of claim 1, further comprising:

an undulating main well bore extending from a surface well bore located at a first end of the layer to a second end of the layer;

a first plurality of lateral well bores extending in spaced apart relation to each other from a first side portion of the undulating main well bore to the periphery of the area; and

a second plurality of lateral well bores extending in spaced apart relation to each other from a second, opposite side portion of the undulating main well bore to the periphery of the area.

8. The subterranean drainage pattern of claim 7, wherein:

each of the first plurality of lateral well bores extend from a bending portion of the undulating main well bore; and

each of the second plurality of lateral well bores extend from a bending portion of the undulating main well bore.

9. The subterranean drainage pattern of claim 7, wherein the wavelength of a waveform is approximately twice the interval spacing between each lateral well bore on a side on the main well bore.

10. The subterranean drainage pattern of claim 7, wherein each lateral well bore comprises:

a radiused portion extending from a bending portion of the undulating main well bore, the radiused portion comprising a radius of curvature that is substantially equal to a radius of curvature of the bending portion of the undulating well bore; and

an elongated portion extending from the radiused portion to the periphery of the area.

11. The subterranean drainage pattern of claim 1, further comprising:

a main well bore extending from a surface well bore located at a first end of the area of the subterranean zone to a second end of the area;

a first plurality of lateral well bores extending in spaced apart relation to each other from a first side portion of the main well bore to the periphery of the area, the first plurality of lateral well bores comprising a plurality of undulating lateral well bores; and

a second plurality of lateral well bores extending in spaced apart relation to each other from a second side portion of the main well bore to the periphery of the area, the second plurality of lateral well bores comprising a plurality of undulating lateral well bores.

12. The subterranean drainage pattern of claim 1, further comprising:

an undulating main well bore extending from a surface well bore to define a first end of the layer to a second end of the layer;

a first plurality of lateral well bores extending in spaced apart relation to each other from a first side portion of the undulating main well bore to the periphery of the area, the first plurality of lateral well bores comprising a plurality of undulating lateral well bores; and

a second plurality of lateral well bores extending in spaced apart relation to each other from a second, opposite side portion of the undulating main well bore to the periphery of the area, the second plurality of lateral well bores comprising a plurality of undulating lateral well bores.

13. A method for accessing an area of a subterranean zone comprising at least one undulating well bore confined with a single layer of subterranean deposits, the method comprising:

drilling at least one inclining portion of a well bore through the subterranean zone at an inclination sloping toward an upper boundary of the single layer of subterranean deposits;

drilling at least one declining portion through the subterranean zone at a declination sloping toward a lower boundary of the single layer of subterranean deposits;

drilling at least one bending portion coupling the at least one inclining portion and the at least one declining portion; and

drilling a plurality of waveforms, each waveform comprising an inclining portion, a declining portion, and a bending portion, wherein the plurality of waveforms vary over space in a substantially periodic manner.

14. The method of claim 13, wherein the single layer comprises hydrocarbons.

15. The method of claim 14, wherein the single layer comprises a coal seam.

16. The method of claim 13, wherein the wavelength of each waveform is greater than six hundred feet.

17. The method of claim 13, wherein the plurality of waveforms have substantially equal wave heights.

18. The method of claim 17, wherein the wave height of each waveform is greater than ten feet.

19. The method of claim 13, further comprising:

drilling an undulating main well bore extending from a surface well bore located at a first end of the layer to a second end of the layer;

drilling a first plurality of lateral well bores extending in spaced apart relation to each other from a first side portion of the undulating main well bore to the periphery of the area; and

drilling a second plurality of lateral well bores extending in spaced apart relation to each other from a second, opposite side portion of the undulating main well bore to the periphery of the area.

20. The method of claim 19, further comprising:

drilling each of the first plurality of lateral well bores extending from a bending portion of the undulating main well bore; and

drilling each of the second plurality of lateral well bores extending from a bending portion of the undulating main well bore.

21. The method of claim 19, further comprising drilling the lateral well bores such that the wavelength of the waveform is approximately twice the interval spacing between each lateral well bore on a side of the main well bore.

22. The method of claim 19, wherein drilling each lateral well bore comprises:

drilling a radiused portion extending from a bending portion of the undulating main well bore, the radiused portion comprising a radius of curvature that is substantially equal to a radius of curvature of the bending portion of the undulating well bore; and

drilling an elongated portion extending from the radiused portion to the periphery of the area.

23. The method of claim 13, further comprising:

drilling a main well bore extending from a surface well bore located at a first end of the layer to a second end of the layer;

drilling a first plurality of lateral well bores extending in spaced apart relation to each other from a first side portion of the main well bore to the periphery of the area, the first plurality of lateral well bores comprising a plurality of undulating lateral well bores; and

forming a second plurality of lateral well bores extending in spaced apart relation to each other from a second side portion of the main well bore to the periphery of the area, the second plurality of lateral well bores comprising a plurality of undulating lateral well bores.

24. The method of claim 13, further comprising:

drilling an undulating main well bore extending from a surface well bore to define a first end of the layer to a second end of the layer;

drilling a first plurality of lateral well bores extending in spaced apart relation to each other from a first side portion of the undulating main well bore to the periphery of the area, the first plurality of lateral well bores comprising a plurality of undulating lateral well bores; and

drilling a second plurality of lateral well bores extending in spaced apart relation to each other from a second side portion of the undulating main well bore to the periphery of the area, the second plurality of lateral well bores comprising a plurality of undulating lateral well bores.