Flexible pipe

Patent metadata

Field	Value
Publication number	US-10197198-B2
Application number	US-201515127090-A
Country	US
Kind code	B2
Filing date	Mar 18, 2015
Priority date	Mar 21, 2014
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

The invention concerns a flexible pipe for offshore applications, such as for use as a riser in oil production. The flexible pipe has a longitudinal axis and contains a pressure resilient core pipe structure with an inner surface defining a bore, and at least a pair of cross wound and non-bonded tensile armor layers surrounding said core pipe structure. The pressure resilient core pipe structure contains an embedded pressure armor structure, wherein the embedded pressure armor structure contains a plurality of layers of helically wound continuous fibers, wound with a winding angle of about 60 degrees or more relative to the longitudinal axis of the pipe and embedded in a cured polymer matrix. The fibers are individually bonded to the cured polymer matrix. Preferably each of said layers of helically wound continuous fibers have a fiber density of at least about 40%.

First claim

What is claimed is:

1. A flexible pipe having a longitudinal axis and comprising a pressure resilient core pipe structure with an inner surface defining a bore, and at least a pair of cross wound and non-bonded tensile armor layers surrounding said core pipe structure, said pressure resilient core pipe structure comprising an embedded pressure armor structure, wherein the embedded pressure armor structure comprises a plurality of layers of helically wound continuous fibers, wound with a winding angle of 60 degrees or more relative to the longitudinal axis of the pipe and embedded in a cured polymer matrix, wherein said fibers are individually bonded to the cured polymer matrix, and each of said layers of helically wound continuous fibers have a fiber density of at least 40%.

2. The flexible pipe of claim 1 , wherein each of said layers of helically wound continuous fibers comprise a plurality of fibers, where each continuous fiber is wound adjacent to neighboring continuous fibers.

3. The flexible pipe claim 1 , wherein at least two of said pluralities of layers of helically wound continuous fibers are embedded in a common layer of cured polymer matrix, said common layer of cured polymer matrix comprises all of said pluralities of layers of helically wound continuous fibers.

4. The flexible pipe of claim 1 , wherein at least two of said pluralities of layers of helically wound continuous fibers are embedded in distinct layer of cured polymer matrix.

5. The flexible pipe of claim 1 , wherein half of the plurality of layers of helically wound continuous fibers are helically wound in a first direction and the remaining of the layers of helically wound continuous fibers are helically wound in the opposite direction of the first direction.

6. The flexible pipe of claim 1 , wherein the plurality of layers of helically wound continuous fibers are arranged in one or more stacks of contacting layers.

7. The flexible pipe of claim 1 , wherein said continuous fibers are selected from the group consisting of: spun fibers from cut fibers, filaments, yarns, braided filaments, carbon fibers, glass fibers, basalt fibers, polymer fibers and combinations thereof.

8. The flexible pipe of claim 1 , wherein the continuous fibers are polymer fibers selected from thermoset polymer fibers, such as epoxy fibers, polyester fibers, vinylester fibers, polyurethane fibers, phenolic fibers and thermoplastic polymer fibers, such as aramide fibers, polypropylene fibers, polyethylene fibers, polycarbonate fibers, thermoplastic polyester fibers and mixtures thereof.

9. The flexible pipe of claim 1 , wherein the continuous fibers of the embedded pressure armor structure are impregnated with a polymer which is different from the cured polymer matrix in which the elongate armor elements are embedded.

10. The flexible pipe of claim 1 , wherein the pressure resilient core pipe structure is a layered structure comprising an inner polymer layer and at least one outer layer surrounding the inner polymer layer.

11. The flexible pipe of claim 10 , wherein the inner polymer layer is substantially free of said continuous fibers.

12. The flexible pipe of claim 10 , wherein the inner polymer layer is of a substantially homogeneous polymer, selected among polyolefins, cross-linked polyolefins, not cross-linked polyolefins, for example polyethylene (PE) or polypropylene (PP); polyamides, for example polyamide 11 (PA-11) or polyamide 12 (PA-12); fluorinated polymers, for example polyvinylidene fluoride (PVDF); polysulfides, for example polyphenylene sulfide (PPS); polyurethanes (PU); polyesters; polyacetals; polyethers, for example polyethersulfone (PES), polyetheretherketone (PEEK) and rubbers such as butyl rubber and combinations thereof.

13. The flexible pipe of claim 1 , wherein said pressure resilient core pipe structure comprises an outermost polymer layer in form of an anti-friction layer, such as a wound anti-friction layer.

14. The flexible pipe of claim 1 , wherein the pressure resilient core pipe structure comprises at least one acidic neutralizing chemically active compound, in the form of a chemically active compound which can neutralize at least one of CO2 and H2S, the chemically active compound is selected from ZnO, PbO, CuO, CdO, NiO, SnO2 and MoO3, cationic clay silicate, such as kaolinite; smectite; lllite; chlorite; and synthetic cationic clays and combinations thereof.

15. A method of producing a flexible pipe of claim 1 , the method comprising providing a pressure resilient core pipe structure with an inner surface defining a bore and a longitudinal axis of the pipe, and winding at least a pair of cross wound and non-bonded tensile armor layers to surround said core pipe structure, wherein the production of said pressure resilient core pipe structure comprises providing at least one layer of a curable polymer matrix and winding a plurality of layers of continuous fibers with a winding angle of 60 degrees or more relative to the longitudinal axis of the pipe such that the individual continuous fibers are embedded in the curable polymer matrix and curing said curable polymer matrix, said curable polymer matrix being partly cured prior to winding of said continuous fibers.

16. The method of claim 15 , wherein the method comprises winding said plurality of layers of continuous fibers one above the other.

17. The method of claim 15 , wherein the method comprises winding said plurality of layers of continuous fibers to be embedded in said curable polymer matrix to ensure that each of said layers of helically wound continuous fibers have a fiber density of at least 40%.

18. The method of claim 15 , wherein the method comprises impregnating said continuous fibers with a curable resin prior to winding.

19. The method of 15 , wherein the method comprises applying a layer of bonding material prior to applying said curable polymer layer for increasing interfacial bonding between the cured polymer layer and an underlying layer.

20. A hybrid riser pipe 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 at least one unbonded flexible metal armored riser section and a composite pipe section, wherein the composite pipe section is a flexible pipe of claim 1 .

Assignees

• Nat Oilwell Varco Denmark Is

Inventors

• Glejbol Kristian

Classifications

• F16L11/083 Primary

  three or more layers · CPC title