Unbonded flexible pipe

Patent metadata

Field	Value
Publication number	US-9523446-B2
Application number	US-201213978181-A
Country	US
Kind code	B2
Filing date	Jan 3, 2012
Priority date	Jan 6, 2011
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

The invention relates to an unbonded flexible pipe for subsea transportation of fluids. The pipe has a length and comprises a tubular inner sealing sheath defining a bore and an axis of the pipe. In a pipe length section it comprises a second sealing sheath surrounding the inner sealing sheath and forming an annulus between the inner sealing sheath and the second sealing sheath. The annulus provides a primary maintaining passage along the length of the pipe length section with a first and a second end. The pipe comprises at least one secondary maintaining passage along the length of the pipe with a first and a second end. The secondary maintaining passage is arranged with an axial distance which is larger than the axial distance of the inner sealing sheath.

First claim

What is claimed is:

1. An unbonded flexible pipe for sub sea transportation of fluids, the pipe has a length and comprises a tubular inner sealing sheath defining a bore and an axis of the pipe and forming a barrier against fluids transported in the bore, the pipe comprises at least one pipe length section comprising a second sealing sheath surrounding the inner sealing sheath and forming an annulus between the inner sealing sheath and the second sealing sheath, the annulus provides a primary maintaining passage along the length of the pipe length section with a first and a second end, the pipe comprises at least one secondary maintaining passage along the length of the pipe with a first and a second end, the secondary maintaining passage is arranged with an axial distance which is larger than the axial distance of the inner sealing sheath, wherein the first end of one of the primary and the secondary maintaining passages is arranged as an input end for a maintaining fluid and the first end of the other of the primary and the secondary maintaining passages is arranged as an outflow end for the maintaining fluid, and the primary and the secondary maintaining passages are in fluidic connection with each other at their second ends to provide a pathway for the maintaining fluid.

2. The unbonded flexible pipe as claimed in claim 1 , wherein the pipe in at least the pipe length section comprises an outermost sealing sheath, the secondary maintaining passage is arranged inside the outermost sealing sheath.

3. The unbonded flexible pipe as claimed in claim 1 , wherein the pipe in at least the pipe length section comprises an outermost sealing sheath providing the second sealing sheath, the pipe in at least the pipe length section comprises at least two armouring layers arranged in the annulus.

4. The unbonded flexible pipe as claimed in claim 1 , wherein the pipe in at least the pipe length section comprises an intermediate sealing sheath providing the second sealing sheath, the pipe in at least the pipe length section comprises at least one armouring layer arranged in the annulus.

5. The unbonded flexible pipe as claimed in claim 4 , wherein the pipe in at least the pipe length section comprises a pressure armouring layer in the annulus.

6. The unbonded flexible pipe as claimed in claim 4 , wherein the pipe in at least the pipe length section comprises a pressure armouring layer and a tensile armour layer in the annulus, the tensile armouring layer is provided by a plurality of helically wound armouring elements, optionally wound with an angle of about 60 degrees or less.

7. The unbonded flexible pipe as claimed in claim 4 , wherein the pipe in at least the pipe length section comprises a third sealing sheath surrounding the second sealing sheath and forming an additional annulus between the second sealing sheath and the third sealing sheath.

8. An unbonded flexible pipe as claimed in claim 7 , wherein the pipe in at least the pipe length section comprises at least one tensile armour layer in the additional annulus, the tensile armouring layer is provided by a plurality of helically wound armouring elements, optionally wound with an angle of about 60 degrees or less.

9. The unbonded flexible pipe as claimed in claim 1 , wherein the insulating layer is an extruded layer, the pipe in at least the pipe length section comprises the maintaining pipe between the insulating layer and an underlying layer, the extruded insulating layer conforms to the shape of the maintaining pipe to at least partly embed the maintaining pipe.

10. The unbonded flexible pipe as claimed in claim 9 , wherein the pipe in at least the pipe length section comprises the maintaining pipe between the insulating layer and an underlying layer, the underlying layer is selected from an outermost sealing sheath, an armouring layer, an intermediate sealing sheath, and the inner sealing sheath.

11. The unbonded flexible pipe as claimed in claim 1 , wherein the pipe in at least the pipe length section comprises an insulating layer in form of a wound layer, the secondary maintaining passage is at least partly embedded in the insulation layer.

12. The unbonded flexible pipe as claimed in claim 11 , wherein the pipe in at least the pipe length section comprises the maintaining pipe between the insulating layer and an underlying layer.

13. The unbonded flexible pipe as claimed in claim 1 , wherein the secondary maintaining passage in at least the pipe length section is arranged with an axial distance which is larger than the axial distance of the first maintaining passage.

14. The unbonded flexible pipe as claimed in claim 1 , wherein the pipe in at least the pipe length section comprises an outermost sealing sheath and the secondary maintaining passage is arranged with an axial distance which is larger than the axial distance of the outermost sealing sheath, the secondary maintaining passage is provided by a maintaining pipe.

15. The unbonded flexible pipe as claimed in claim 1 , wherein the pipe in at least the pipe length section comprises an outermost sealing sheath and the secondary maintaining passage is arranged fully or partly outside the outermost sealing sheath.

16. The unbonded flexible pipe as claimed in claim 1 , wherein the secondary maintaining passage in at least the pipe length section of the pipe is provided by a maintaining pipe.

17. The unbonded flexible pipe as claimed in claim 16 , wherein the maintaining pipe is made of one or more materials comprising at least one of metals; polymers and combinations of metal and polymer.

18. The unbonded flexible pipe as claimed in claim 1 , wherein the secondary maintaining passage in at least the pipe length section of the pipe is provided by a maintaining pipe and at least a length of the maintaining pipe is located outside an outermost layer of the pipe.

19. The unbonded flexible pipe as claimed in claim 1 , wherein the secondary maintaining passage is substantially identical along the length of the pipe length section.

20. The unbonded flexible pipe as claimed in claim 1 , wherein the secondary maintaining passage varies along the length of the pipe length section.

21. The unbonded flexible pipe as claimed in claim 1 , wherein the secondary maintaining passage has a cross-sectional area of at least about 3 mm 2 .

22. The unbonded flexible pipe as claimed in claim 1 , wherein the secondary maintaining passage per Km of the pipe length section has a cross-sectional area of at least about 10 mm 2 .

23. The unbonded flexible pipe as claimed in claim 1 , wherein the secondary maintaining passage has a cross-sectional area between from about 3 mm 2 to about 200 2 mm.

24. The unbonded flexible pipe as claimed in claim 1 , wherein the pipe length section comprises an end-fitting coupled to and terminating an end of said pipe length section, the end fitting comprises a primary end-fitting passage in fluidic connection with the primary maintaining passage and the end fitting comprises a secondary end-fitting passage in fluidic connection with the secondary maintaining passage.

25. The unbonded flexible pipe as claimed in claim 24 , wherein the pipe comprises at least two interconnected pipe length sections each comprising an end-fitting coupled to and terminating an end of said respective pipe length sections, the end-fittings provide at least a part of a connecting assembly interconnecting the pipe length sections, the end fittings each

Assignees

• Kassow Kristian
• Glejbøl Kristian
• Nat Oilwell Varco Denmark Is

Inventors

• Kassow Kristian
• Glejbøl Kristian

Classifications

• F16L33/01

  specially adapted for hoses having a multi-layer wall · CPC title

• F16L11/22

  Multi-channel hoses · CPC title

• F16L11/083 Primary

  three or more layers · CPC title

• F16L11/20 Primary

  Double-walled hoses · CPC title

• F16L11/12

  with arrangements for particular purposes, e.g. specially profiled, with protecting layer, heated, electrically conducting (F16L11/11 takes precedence) · CPC title