Offshore installation

Patent metadata

Field	Value
Publication number	US-10975629-B2
Application number	US-201716341090-A
Country	US
Kind code	B2
Filing date	Oct 11, 2017
Priority date	Oct 17, 2016
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

An offshore installation comprising a riser pipe and a bend stiffener. The riser pipe comprises a flexible pipe body having a pipe length and an end fitting and the riser has a longitudinal pipe axis. The bend stiffener comprises a helically shaped body arranged to surround a stiffened length section of the flexible pipe body. The bend stiffener has a root end and a far end, wherein the root end is closer to the end fitting than the far end and the root end is locked at an axial distance to the end fitting, determined along the longitudinal pipe axis.

First claim

What is claimed is:

1. An offshore installation comprising a riser pipe and a bend stiffener, wherein the riser pipe comprises a flexible pipe body and an end fitting and a longitudinal pipe axis, said pipe body has a pipe length, said bend stiffener comprises a helically shaped body arranged to surround a stiffened length section of the flexible pipe body, the bend stiffener has a root end and a far end, wherein the root end is closer to the end fitting than the far end and the root end is locked at a distance to the end fitting, determined along the longitudinal pipe axis to provide a fixed distance along the length of the pipe axis between the end fitting and the root end of the bend stiffener.

2. The offshore installation of claim 1 , wherein the pipe body comprises a composite of layered materials that forms a pressure-containing conduit.

3. The offshore installation of claim 1 , wherein said stiffened length section of the flexible pipe body is in the vicinity of a subsea installation or in the vicinity of a surface installation to which the riser is connected.

4. The offshore installation of claim 1 , wherein said root end of the bend stiffener is mechanically locked to said end fitting via a support structure defining the distance between the end fitting and the root end.

5. The offshore installation of claim 1 , wherein the installation comprises a support structure, said root end of the bend stiffener is supported by and/or attached to said support structure.

6. The offshore installation of claim 5 , wherein said support structure comprises a rigid structure arranged to lock said end fitting and said root end of the bend stiffener in a position relative to each other.

7. The offshore installation of claim 5 , wherein said support structure comprises a tube, arranged to lock said end fitting and said root end of the bend stiffener.

8. The offshore installation of claim 1 , wherein the bend stiffener is rotarily movable with respect to a support structure.

9. The offshore installation of claim 1 , wherein the bend stiffener is angularly movable with respect to a support structure.

10. The offshore installation of claim 1 , wherein the bend stiffener is stiffly attached to a support structure.

11. The offshore installation of claim 1 , wherein the bend stiffener root end comprises a collar, said collar being attached to the pipe and/or a support structure for locking the bend stiffener root end at an axial distance to the end fitting.

12. The offshore installation of claim 1 , wherein said stiffened length section of said flexible pipe body is surrounded by at least one helical winding.

13. The offshore installation of claim 1 , wherein at least a length section L 1 of the helically shaped body is arranged to rest against an outer sheath of the pipe, said length section L 1 of the helically shaped body has an inner diameter corresponding to an outer diameter of the outer sheath.

14. The offshore installation of claim 1 , wherein said bend stiffener helically shaped body has an inner diameter which is essentially constant along a length of the helically shaped body.

15. The offshore installation of claim 1 , wherein said bend stiffener helically shaped body has an inner diameter, which varies along a length of the helically shaped body.

16. The offshore installation of claim 1 , wherein said helically shaped body comprises a helical string of solid material wound to surround the pipe, said helically shaped body is helix shaped in at least a part of a length of the helically shaped body.

17. The offshore installation of claim 16 , wherein said helical string comprises at least two full windings surrounding the pipe.

18. The offshore installation of claim 17 , wherein said helical string windings have an angle to a bend stiffener axis of from about 30° to about 65°.

19. The offshore installation of claim 1 , wherein said helically shaped body comprises two or more helical strings of solid material wound to surround the pipe, said two or more helical strings are wound in the same directions.

20. The offshore installation of claim 1 , wherein said helically shaped body has a bend stiffness (flexural rigidity) which is larger than a bend stiffness of the pipe surrounded by said helically shaped body.

21. The offshore installation of claim 1 , wherein a rigid rod is interposed between the root end and the end fitting along the longitudinal pipe axis, and wherein the fixed distance substantially corresponds to the length of the rigid rod.

22. An offshore installation comprising a riser pipe and a bend stiffener, wherein the riser pipe comprises a flexible pipe body and an end fitting and a longitudinal pipe axis, said pipe body has a pipe length, said bend stiffener comprises a helically shaped body arranged to surround a stiffened length section of the flexible pipe body, the bend stiffener has a root end and a far end, wherein the root end is closer to the end fitting than the far end and the root end is locked at an axial distance to the end fitting, determined along the longitudinal pipe axis and wherein the helically shaped body comprises a helical string of solid material wound to surround the pipe.

Assignees

• Nat Oilwell Varco Denmark Is

Inventors

• Thomsen Jens Rordam

Classifications

• F16L11/082

  two layers · CPC title

• F16L57/02 Primary

  against cracking or buckling · CPC title

• E21B17/017 Primary

  Bend restrictors for limiting stress on risers · CPC title

• F16L35/00

  Special arrangements used in connection with end fittings of hoses, e.g. safety or protecting devices · CPC title

• F16L1/123

  Devices for the protection of pipes under water · CPC title