Buoyancy control systems for tubes

• US 20030008577A1
• Filed: 04/29/2002
• Published: 01/09/2003
• Est. Priority Date: 04/27/2001
• Status: Active Grant

• Current Assignee: Fiberspar Corp. (NOV, Inc.)
• Original Assignee: Fiberspar Corp. (NOV, Inc.)
• Inventors: Quigley, Peter A., Nolet, Stephen C., Wideman, Thomas W.
• Granted Patent: US 6,663,453 B2
• Time in Patent Office: Days
• US Class Current: 441/133
• CPC Class Codes: B32B 1/08 Tubular products
• CPC Class Codes: B32B 2597/00 Tubular articles, e.g. hoses, pipes
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: E21B 17/00 Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
• CPC Class Codes: E21B 17/20 Flexible or articulated drilling pipes , e.g. flexible or articulated rods, pipes or cables
• CPC Class Codes: F16L 1/163 by varying the apparent weight of the pipe during the laying operation
• CPC Class Codes: F16L 1/24 Floats; Weights
• CPC Class Codes: F16L 58/00 Protection of pipes or pipe fittings against corrosion or incrustation compound tubes F16L9/14
• CPC Class Codes: F16L 59/143 Pre-insulated pipes
• CPC Class Codes: F16L 9/00 Rigid pipes
• CPC Class Codes: F16L 9/12 of plastics with or without reinforcement F16L9/16 - F16L9/22 take precedence
• CPC Class Codes: F16L 9/14 Compound tubes, i.e. made of materials not wholly covered by any one of the preceding groups F16L9/16 - F16L9/22 take precedence
• CPC Class Codes: F16L 9/18 Double-walled pipes; Multi-channel pipes or pipe assemblies
• CPC Class Codes: F16L 9/19 Multi-channel pipes or pipe assemblies
• CPC Class Codes: F16L 9/20 Pipe assemblies
• CPC Class Codes: Y10T 428/1393 Multilayer [continuous layer]

Abstract

A buoyancy control system for controlling the buoyancy of a tube may includes generally tubular length of buoyancy control material having a selected buoyancy characteristic. The length of buoyancy control material may be attached to a section of the length of the tube to adjust the buoyancy of the section of the tube. The length of buoyancy control material may be an integral, coaxial layer of the tube or, alternatively, the length of buoyancy control material may be externally attached to tube. In embodiments in which the length of the buoyancy control material is externally attached, the buoyancy control material may have a longitudinal axis that is spaced-apart from a longitudinal axis of the tube.

Claims

1. A buoyancy control system for controlling the buoyancy of a tube, the system comprising:

a generally tubular length of buoyancy control material having a selected buoyancy characteristic, the length of buoyancy control material being attached to a section of the length of the tube to adjust the buoyancy of the section of the tube.

2. The buoyancy control system of claim 1, wherein the length of buoyancy control material is an integral, coaxial layer of the tube.

3. The buoyancy control system of claim 1, wherein the length of buoyancy control material is externally attached to tube.

4. The buoyancy control system of claim 3, wherein the length of the buoyancy control material has a longitudinal axis that is spaced-apart from a longitudinal axis of the tube.

5. The buoyancy control system of claim 1, wherein the buoyancy control material is positively buoyant.

6. The buoyancy control system of claim 5, wherein the buoyancy control material is a foam material.

7. The buoyancy control system of claim 5, wherein the foam material is a thermoplastic, a thermosett material, or a thermoplastic elastomer.

8. The buoyancy control system of claim 5, wherein the buoyancy control material is a low density polymer having a specific gravity of less than or equal to 1.

9. The buoyancy control system of claim 1, wherein the buoyancy control material is negatively buoyant.

10. The buoyancy control system of claim 9, wherein the buoyancy control material has a specific gravity greater than or equal to 1.25.

11. The buoyancy control system of claim 10, wherein the buoyancy control material has a specific gravity greater than or equal to 2.0.

12. The buoyancy control system of claim 9, wherein the buoyancy control material is a slurry.

13. The buoyancy control system of claim 9, wherein the buoyancy control material is a liquid.

14. The buoyancy control system of claim 9, wherein the buoyancy control material includes a curing agent, a hardener, or a gellation agent to cause the buoyancy control material to set after a selected time period.

15. The buoyancy control system of claim 9, wherein the buoyancy control material is displaceable along the section of the tube.

16. The buoyancy control system of claim 1, further comprising a containment layer positioned about the buoyancy control material.

17. The buoyancy control system of claim 16, wherein the containment layer is generally tubular in shape.

18. The buoyancy control system of claim 16, wherein the containment layer is collapsible and expandable.

19. The buoyancy control system of claim 16, wherein the containment layer has a diameter approximate to a diameter of the tube.

20. The buoyancy control system of claim 16, wherein the containment layer and the buoyancy control material are spoolable on a reel.

21. The buoyancy control system of claim 16, further comprising an outer jacket that encapsulates at least a portion of the tube and the containment layer.

22. The buoyancy control system of claim 21, wherein the outer jacket further comprises at least one energy conductor coupled thereto.

23. The buoyancy control system of claim 22, wherein the energy conductor is embedded within the outer jacket.

24. The buoyancy control system of claim 21, further comprising one or more sensors positioned along the length of the tube.

25. The buoyancy control system of claim 24, wherein the sensors are coupled to the outer jacket.

26. The buoyancy control system of claim 16, wherein the containment layer is continuously bonded to the section of the tube.

27. The buoyancy control system of claim 16, wherein the containment layer is discretely attached to the section of tube.

29. The composite tube of claim 28, wherein the buoyancy control layer is interposed between the internal liner and the composite layer.

30. The composite tube of claim 29, wherein the buoyancy control layer is positioned externally to the composite layer.

31. The composite tube of claim 30, further comprising a containment layer positioned externally to the buoyancy control layer.

28. A composite tube comprising:

a substantially fluid impervious internal liner,

a composite layer of fibers embedded within a matrix material, and

a buoyancy control layer formed of a buoyancy control material having a specific gravity of greater or equal to 1.25.

32. A composite tube comprising:

a substantially fluid impervious internal liner,

a composite layer of fibers embedded within a matrix material, and

a buoyancy control layer formed of a buoyancy control material having a specific gravity of less than over equal to 1.

33. A buoyancy control system for controlling the buoyancy of a tube, the system comprising:

a buoyancy control material having a selected buoyancy characteristic,

a generally tubular containment layer attached to a longitudinal section of the tube, the buoyancy control material being positioned within the containment layer, and

means for selectively displacing the buoyancy control material along the length of the containment layer to selectively adjust the position of the buoyancy control material within the containment layer.

34. The buoyancy control system of claim 33, wherein the means for selectively displacing comprise one or more pumps.

35. The buoyancy control system of claim 33, further comprising one or more sensors positioned a long the length of the tube for monitoring changes in environmental conditions.

36. The buoyancy control system of claim 35, further comprising a processor connected to the sensors and receiving data therefrom, the processor controlling operation of the means for selectively displacing the buoyancy control material in response to the date received from the sensors.

37. A buoyancy control system for controlling the buoyancy of a tube, the system comprising:

a buoyancy control material having a selected buoyancy characteristic,

a generally tubular containment layer attached to a longitudinal section of the tube, the buoyancy control material being positioned within the containment layer, and

a pump operable to displace the buoyancy control material along the length of the containment layer to selectively adjust the position of the buoyancy control material within the containment layer.