Riser and an offshore system

Patent metadata

Field	Value
Publication number	US-9303463-B2
Application number	US-201314405951-A
Country	US
Kind code	B2
Filing date	Jun 3, 2013
Priority date	Jun 6, 2012
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

The invention relates to a riser for transporting fluid between an upper facility and a subsea facility. The riser has a center axis and a length along the center axis and comprises an unbonded flexible metal armored riser section and an unbonded flexible composite armored riser section arranged in fluid connection to each other. The metal armored riser section comprises at least two cross-wound tensile armor layers each comprising a plurality of helically wound elongate metal armor elements wound with a winding angle of about 60 degree or less relative to the center axis. The composite armored riser section comprises at least one tensile armor layer comprising a plurality of helically wound elongate composite armor elements wound with a winding angle of about 60 degree or less relative to the center axis.
The invention also relates to an offshore system comprising such riser.

First claim

What is claimed is:

1. A riser for transporting fluid between an upper facility and a subsea facility, the riser has a center axis and a length along the center axis and comprises an unbonded flexible metal armored riser section and an unbonded flexible composite armored riser section arranged in fluid connection to each other, said metal armored riser section comprises at least two cross-wound tensile armor layers each comprising a plurality of helically wound elongate metal armor elements wound with a winding angle of about 60 degree or less relative to the center axis, and said composite armored riser section comprises at least one tensile armor layer comprising a plurality of helically wound elongate composite armor elements wound with a winding angle of about 60 degree or less relative to the center axis, wherein the helically wound elongate composite armor elements comprise strips or bundles of strips made of fiber-reinforced polymer.

2. The riser as claimed in claim 1 , wherein said metal armored riser section is adapted to be arranged closer to said upper facility than said composite armored riser section, the metal armored riser section and the composite armored riser section advantageously being arranged adjacent to each other.

3. The riser as claimed in claim 1 , wherein said metal armored riser section comprises a liquid impervious inner sealing sheath defining a bore and sealing against outflow from said bore and a liquid impervious outer sealing sheath sealing against ingress of water and one or more intermediate liquid impervious sheath(s), said liquid impervious sheaths form at least one annulus, at least one of said cross-wound tensile armor layers being arranged in said annulus.

4. The riser as claimed in claim 3 , wherein said annulus comprises a venting opening for allowing fluid to escape from the annulus, and wherein the annulus additionally comprises a fluid inlet opening.

5. The riser as claimed in claim 3 , wherein said annulus comprises a venting opening for allowing fluid to escape from the annulus, said venting opening comprises a relief valve.

6. The riser as claimed in claim 3 , wherein the annulus additionally comprises a fluid inlet opening.

7. The riser as claimed in claim 3 , wherein said annulus comprises a venting opening for allowing fluid to escape from the annulus, said metal armored riser section comprises an adjacent end-fitting, the venting opening is arranged in said end-fitting.

8. The riser as claimed in claim 3 , wherein said annulus comprises a venting opening for allowing fluid to escape from the annulus, said venting opening is arranged above water line or the venting opening is in fluid connection with a passage leading above the water line.

9. The riser as claimed in claim 1 , wherein at least two or more tensile armor layers of said composite armored riser section are in direct contact with sea water.

10. The riser as claimed in claim 1 , wherein said composite armored riser section comprises a liquid impervious inner sealing sheath defining a bore and sealing against outflow from said bore, one or more intermediate liquid impervious sheath(s) arranged closer to the center axis than said tensile armor layer or layers, and a liquid permeable outer protection layer.

11. The riser as claimed in claim 1 , wherein said at least two or more tensile armor layers of said composite armored riser section are not arranged in an annulus.

12. The riser as claimed in claim 1 , wherein said composite armored riser section does not comprise any annulus.

13. The riser as claimed in claim 1 , wherein said composite armored riser section comprises an annulus, said annulus housing a pressure armor layer comprising at least one helically would metal armor element, wound with a winding angle of about 70 degree or more relative to the center axis.

14. The riser as claimed in claim 1 , wherein said metal armored riser section and said composite armored riser section each have a lowermost end and an uppermost end, at least the uppermost end or the lowermost end of said metal armored riser section is terminated by an end fitting and at least the uppermost end or the lowermost end of said composite armored riser section is terminated by an end-fitting, wherein the end-fitting of the metal armored riser section is connected to the end-fitting of the composite armored riser section.

15. The riser as claimed in claim 1 , wherein said metal armored riser section and said composite armored riser section comprise a liquid impervious inner sealing sheath defining a bore and sealing against outflow from said bore, wherein said inner sealing sheath is a common inner sealing sheath for said metal armored riser section and said composite armored riser section.

16. The riser as claimed in claim 1 , wherein said metal armored riser section and said composite armored riser section comprise a pressure armor layer, said pressure armor layer being a common pressure armor layer.

17. The riser as claimed in claim 1 , wherein said metal armored riser section and said composite armored riser section comprise a carcass, said carcass being a common pressure armor layer.

18. The riser as claimed in claim 3 , wherein at least one tensile armor layer of said metal armored riser section is terminated in a metal armored riser section annular termination unit, at least the inner sealing sheath is not terminated in said metal armored riser section annular termination unit.

19. The riser as claimed in claim 3 , wherein said at least one tensile armor layer of said composite armored riser section is terminated in a composite armored riser section annular termination unit, at least the inner sealing sheath is not terminated in said composite armored riser section annular termination unit.

20. The riser as claimed in claim 3 , wherein at least one tensile armor layer of said metal armored riser section is terminated in a metal armored riser section annular termination unit, the metal armored riser section comprises a carcass on the inner side of said inner sealing sheath, said carcass is not terminated in said metal armored riser section annular termination unit.

21. The riser as claimed in claim 1 , wherein at least one tensile armor layer of said metal armored riser section is terminated in a metal armored riser section annular termination unit, the metal armored riser section comprises a pressure armor layer, said pressure armor layer is not terminated in said metal armored riser section annular termination unit.

22. The riser as claimed in claim 18 , wherein at least one tensile armor layer of said metal armored riser section is terminated in a metal armored riser section annular termination unit, the metal armored riser section comprises a liquid impervious outer sealing sheath, said liquid impervious outer sealing sheath is terminated in a sealing connection in the metal armored riser section annular termination unit.

23. The riser as claimed in claim 1 , wherein said at least one tensile armor layer of said composite armored riser section is terminated in a composite armored riser section annular termination unit, the composite armored riser section comprises a carcass on the inner side of said inner sealing sheath, said carcass is not terminated in said composite armored riser section annular termination unit.

24. The riser as claimed in claim 1 , wherein said at least one tensile armor layer of said composite armored riser section is terminated in a composite a

Assignees

• Nat Oilwell Varco Denmark Is

Inventors

• Glejbol Kristian
• Nielsen Niels J Rishoj

Classifications

• F16L33/01

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

• E21B17/015

  Non-vertical risers, e.g. articulated or catenary-type · CPC title

• E21B17/01 Primary

  Risers · CPC title

• F16L11/083

  three or more layers · CPC title

• E21B17/085

  Riser connections (connectors for wellhead E21B33/038) · CPC title