Sealing arrangements for subsea pipe-in-pipe systems

Patent metadata

Field	Value
Publication number	US-10344539-B2
Application number	US-201615547798-A
Country	US
Kind code	B2
Filing date	Feb 2, 2016
Priority date	Feb 3, 2015
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

A method of sealing an annulus between inner and outer pipe sections of a pipe-in-pipe system includes positioning a sealing mass in the annulus in contact with the inner and outer pipe sections. Deforming the sealing mass occurs, for example by shearing and compression, by effecting relative longitudinal movement between the inner and outer pipe sections. Fixing the inner and outer pipe sections against reverse relative longitudinal movement to maintain deformation of the sealing mass is then performed. The inner pipe section and a displaced outer pipe section may be fixed by welding them to respective pipes of an adjoining pipe-in-pipe structure. Opposed ramp surfaces, each being similarly inclined relative to the longitudinal direction, extend into the annulus from respective ones of the pipe sections such that the sealing mass may be compressed between the ramp surfaces.

First claim

The invention claimed is:

1. A method of sealing an annulus between inner and outer pipe sections of a pipe-in- pipe system, the method comprising:
positioning a sealing mass in the annulus in contact with the inner and outer pipe sections;
deforming the sealing mass by effecting relative longitudinal movement between the inner and outer pipe sections;
providing a pipe-in-pipe structure comprising inner and outer pipes; and
fixing the inner and outer pipe sections against reverse relative longitudinal movement to maintain deformation of the sealing mass by fixing the inner pipe section to the inner pipe of the pipe-in-pipe structure and the outer pipe section to the outer pipe of the pipe-in-pipe structure.

2. The method of claim 1 , comprising shearing the sealing mass between the inner and outer pipe sections.

3. The method of claim 1 , comprising compressing the sealing mass between the inner and outer pipe sections.

4. The method of claim 3 , comprising compressing the sealing mass by advancing a ramp surface extending into the annulus from at least one of the inner and outer pipe sections, the ramp surface being inclined relative to the direction of longitudinal movement.

5. The method of claim 4 , comprising compressing the sealing mass between opposed ramp surfaces extending into the annulus from respective ones of the inner and outer pipe sections, said relative longitudinal movement between the inner and outer pipe sections moving the opposed ramp surfaces toward each other.

6. The method of claim 4 , wherein the or each ramp surface has an inclination of 5 ° to 10 ° relative to the direction of longitudinal movement.

7. The method of claim 1 , comprising positioning the sealing mass by casting or moulding the sealing mass in situ between the inner and outer pipe sections.

8. The method of claim 1 , comprising positioning the sealing mass on the inner pipe section before placing the outer pipe section around the sealing mass and the inner pipe section.

9. The method of claim 1 , comprising positioning the sealing mass around at least one elongate element extending longitudinally along the annulus.

10. The method of claim 9 , preceded by placing the or each elongate element on the inner pipe section.

11. The method of claim 10 , comprising diverting the or each elongate element over a radial projection of the inner pipe section.

12. The method of claim 10 , comprising extending the or each elongate element through a radial projection of the inner pipe section.

13. The method of claim 9 , wherein at least one elongate element is a heating element.

14. The method of claim 1 , comprising:
fixing the inner pipe section to an inner pipe of the pipe-in-pipe structure before arranging the outer pipe section around the inner pipe section, axially spaced from the outer pipe of the pipe-in-pipe structure;
placing the sealing mass between opposed faces of the inner and outer pipe sections;
displacing the outer pipe section toward the structure to deform the sealing mass; and
fixing the displaced outer pipe section to the outer pipe of the pipe-in-pipe structure.

15. The method of claim 14 , comprising fixing the inner pipe section and the displaced outer pipe section by welding them to the respective pipes of the structure.

16. A pipe-in-pipe system comprising an annulus defined between inner and outer pipe sections, the system comprising:
a sealing mass positioned in the annulus in contact with the pipe sections, the sealing mass having been deformed by relative longitudinal movement between the pipe sections; and
at least one fixing at an end of at least one of the pipe sections that holds the pipe sections against reverse relative longitudinal movement to maintain the deformation of the sealing mass, wherein the or each fixing comprises at least one of a fixing between the outer pipe section and an outer pipe of an adjoining pipe-in-pipe structure and a fixing between the inner pipe section and an inner pipe of an adjoining pipe-in-pipe structure.

17. The system of claim 16 , wherein the or each fixing comprises a weld between the outer pipe section and an outer pipe of an adjoining pipe-in-pipe structure.

18. The system of claim 16 , wherein the sealing mass is deformed by shearing between the pipe sections.

19. The system of claim 16 , wherein the sealing mass is deformed by compression between the pipe sections.

20. The system of claim 16 , wherein at least one ramp surface extends into the annulus from at least one of the pipe sections toward the other of the pipe sections, the ramp surface being inclined relative to the longitudinal direction and bearing on the sealing mass to deform the sealing mass.

21. The system of claim 20 , wherein a ramp surface extending into the annulus from the inner pipe section faces away from the or each fixing.

22. The system of claim 20 , wherein a ramp surface extending into the annulus from the outer pipe section faces toward the or each fixing.

23. The system of claim 20 , comprising opposed ramp surfaces, each inclined relative to the longitudinal direction, extending into the annulus from respective ones of the pipe sections, the sealing mass being compressed between the ramp surfaces.

24. The system of claim 23 , wherein the ramp surfaces have substantially identical inclinations relative to the longitudinal direction.

25. The system of claim 20 , wherein the or each ramp surface has an inclination of 5° to 10° relative to the longitudinal direction.

26. The system of claim 20 , wherein at least one projection extends radially into the annulus from at least one of the pipe sections toward the other of the pipe sections to define the or each ramp surface.

27. The system of claim 26 , wherein the or each radially-extending projection has a smoothly-rounded apex adjoining the ramp surface.

28. The system of claim 16 , wherein the sealing mass surrounds at least one elongate element extending longitudinally along the annulus.

29. The system of claim 26 , wherein the sealing mass surrounds at least one elongate element extending longitudinally along the annulus.

30. The system of claim 29 , wherein the or each elongate element is diverted over a radially-extending projection of the inner pipe section.

31. The system of claim 29 , wherein the or each elongate element extends through a radially-extending projection of the inner pipe section.

32. The system of claim 29 , wherein at least one elongate element is a heating element.

Assignees

• Acergy France SAS

Inventors

• Gerometta Gerald
• Delaunay Nathalie
• Rousseau Henri

Classifications

• F16L1/123

  Devices for the protection of pipes under water · CPC title

• F16L1/16

  on the bottom · CPC title

• F16L53/30

  Heating of pipes or pipe systems · CPC title

• E21B36/04

  using electrical heaters · CPC title

• E21B36/003

  Insulating arrangements · CPC title