Flexible unbonded pipe and a method for producing such pipe

• US 20070036925A1
• Filed: 09/20/2004
• Published: 02/15/2007
• Est. Priority Date: 09/19/2003
• Status: Active Grant

• Current Assignee: National Oilwell Varco Denmark I/S (NOV, Inc.)
• Original Assignee: Nkt Flexibles I/S
• Inventors: Braad, Poul
• Granted Patent: US 7,976,920 B2
• Time in Patent Office: Days
• US Class Current: 428/36.900
• CPC Class Codes: B32B 1/08 Tubular products
• CPC Class Codes: B32B 15/08 of synthetic resin
• CPC Class Codes: B32B 15/085 comprising polyolefins
• CPC Class Codes: B32B 15/18 comprising iron or steel B32B15/011, B32B15/012 and B32B15/013 take precedence
• CPC Class Codes: B32B 15/20 comprising aluminium or copper B32B15/016 and B32B15/017 take precedence
• CPC Class Codes: B32B 2038/0076 Curing, vulcanising, cross-linking
• CPC Class Codes: B32B 2305/72 Cured, e.g. vulcanised, cross-linked
• CPC Class Codes: B32B 2307/306 Resistant to heat
• CPC Class Codes: B32B 2310/14 Corona, ionisation, electrical discharge, plasma treatment
• CPC Class Codes: B32B 2311/24 Aluminium
• CPC Class Codes: B32B 2311/30 Iron, e.g. steel
• CPC Class Codes: B32B 2323/04 Polyethylene
• CPC Class Codes: B32B 2327/12 containing fluorine
• CPC Class Codes: B32B 2597/00 Tubular articles, e.g. hoses, pipes
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 37/153 at least one layer is extruded and immediately laminated while in semi-molten state
• CPC Class Codes: B32B 38/0008 Electrical discharge treatment, e.g. corona, plasma treatment; wave energy or particle radiation heat treatment B32B38/0036
• CPC Class Codes: F16L 11/081 comprising one or more layers of a helically wound cord or wire in combination with braided layers F16L11/088
• CPC Class Codes: F16L 2011/047 with a diffusion barrier layer
• CPC Class Codes: Y10T 428/1355 Elemental metal containing [e.g., substrate, foil, film, coating, etc.]
• CPC Class Codes: Y10T 428/139 : Open-ended, self-supporting conduit, cylinder, or tube-type article
• CPC Class Codes: Y10T 428/1393 : Multilayer [continuous layer]

Abstract

The present invention relates to a flexible unbonded pipe comprising an inner liner capable of forming a barrier against outflow of a fluid which is conveyed through the pipe, and one or more armouring layers on the outer side of the inner line. The flexible unbonded pipe comprises at least one polymer layer and one film layer, said polymer layer being bonded to said film layer. The film layer may preferably be a metal film layer, such as aluminum film, stainless steel film or duplex film. The polymer layer may preferably be cross-linked polyethylene. The interfacial bonding between the polymer layer and the film layer should preferably be sufficiently strong to prevent creation of gas pockets between the layers when subjected to an increased pressure of aggressive fluids (hydrogen, sulphides, methane and carbon dioxide) on the film side of the pipe. Thereby, it is possible to protect armour layer(s) from aggressive fluids.

Claims

1. A flexible unbonded pipe said pipe, comprising at least one polymer layer having a thickness of 4 mm or more and at least one film layer having a thickness of 1 mm or less, said film layer providing a fluid permeation barrier against one or more of the fluids methane, hydrogen sulphides, carbon dioxides and water, which is higher than the fluid permeation barrier provided by the polymer layer determined at 50°

C. and a pressure difference of 50 bar, and said polymer layer being bonded to said film layer.

2. A flexible pipe according to claim 1 wherein the polymer layer comprises one or more of the polymers selected from the group consisting of polyolefins;

polyamide;

polyimide (PI);

polyurethanes;

polyureas;

polyesters;

polyacetals;

polyethers;

polyoxides;

polysulfides;

polysulphones;

polyacrylates;

polyethylene terephthalate (PET);

polyether-ether-ketones (PEEK);

polyvinyls;

polyacrylonitrils;

polyetherketoneketone (PEKK);

copolymers of the preceding and fluorous polymers.

3. A flexible pipe according to claim 2 wherein the polymer layer comprises cross-linked polyethylene (XLPE).

4. A flexible pipe according to claim 1 wherein the film layer is of a material selected from the group consisting of polymer, metal, metal containing compositions and combinations thereof.

5. A flexible pipe according to claim 4 wherein the film layer is a polymer film comprising one or more of the polymer material selected from the group consisting of polyolefins;

polyamide;

polyimide (PI);

polyurethanes;

polyureas;

polyesters;

polyacetals;

polyethers;

polyoxides;

polysulfides;

polysulphones;

polyacrylates;

polyethylene terephthalate (PET);

polyether-ether-ketones (PEEK);

polyvinyls;

polyacrylonitrils;

polyetherketoneketone (PEKK);

copolymers of the preceding and fluorous polymers.

6. A flexible pipe according to claim 4 wherein the film layer is a metal film selected from the group consisting of aluminum, stainless steel and duplex.

7. A flexible offshore pipe according to claim 4 wherein the film layer is a layered material comprising at least one metal layer.

8. A flexible pipe according to claim 4 wherein the film layer comprises metal-containing compositions.

9. A flexible pipe according to claim 4 wherein the film layer comprises a mixture of polymer with particles selected from the group consisting of carbon particles, metal particles, metal-containing particles, and mixtures thereof.

10. A flexible pipe according to claim 1 wherein the polymer layer is bonded to the film layer via one or more bondings selected from the group of chemical bondings and physical bondings.

11. A flexible pipe according to claim 10 wherein the polymer layer is bonded to the film layer via one or more bondings comprising at least one of the chemical bondings selected from the group of ion bondings and covalent bondings.

12. A flexible pipe according to claim 1 wherein the bonding between the polymer layer and the film layer is stronger than the internal bondings in one of the polymer layer and the film layer.

13. A flexible pipe according to claim 12 wherein the film layer is a layered material, and all interface bondings including bondings between layers of the film and bonding between the polymer layer and the film layer, are stronger than the internal bondings in one of the polymer layer and the film layer.

14. A flexible pipe according to claim 12 wherein the interface bonding(s) is/are stronger than the internal bonding of the polymer layer.

15. A flexible pipe according to claim 1 wherein the interfacial bonding between the polymer layer and the film layer is sufficiently strong to prevent creation of gas pockets between the layers when subjected to an increased carbon dioxides pressure on the film side of the pipe.

16. A flexible pipe according to claim 1 wherein the bonding between the polymer layer and the film layer has a peel strength using ASTM D3330 of at least 300 N/m.

17. A flexible pipe according to claim 1 wherein the bonding between the polymer layer and the film layer is stronger than the cohesive forces in one of the polymer layer and the film layer measured by 90°

peel test.

18. A flexible pipe according to claim 1 wherein the surface of the film facing the polymer layer comprises a primer.

19. A flexible pipe according to claim 1 wherein the polymer layer has a thickness between 4 and 20 mm.

20. A flexible pipe according to claim 1 wherein the polymer layer is at least 10 times thicker than the film layer.

21. A flexible pipe according to claim 1 wherein the film layer has a thickness of about 25 μ

m or more.

22. A flexible pipe according to claim 1 wherein the film layer provides a fluid permeation barrier against at least one of the fluids selected from methane, hydrogen sulphides, carbon dioxides and water, which is at least 50% higher than the fluid permeation barrier provided by the polymer layer determined at 50°

C. and a pressure difference of 50 bar.

23. A flexible pipe according to claim 1 wherein the film layer provides a fluid permeation barrier against all of the fluids methane, hydrogen sulphides, carbon dioxides and water, which is higher than the fluid permeation barrier provided by the polymer layer determined at 50°

C. and a pressure difference of 50 bar.

24. A flexible pipe according to claim 22 wherein the film layer is essentially impermeable to at least one of the fluids selected from hydrogen sulfides, methane, and carbon dioxide, at a partial pressure for the respective fluid on a first side of the layer of at least 0.03 bars measured at about 50°

C. and a pressure difference of 50 bar.

25. A flexible pipe according to claim 22 wherein the film layer is essentially impermeable to H₂O, measured at about 50°

C. and a pressure difference of 50 bar.

26. A flexible pipe according to claim 22 wherein the film layer is essentially impermeable to hydrogen sulfides at a partial pressure of at least 0.03 bars at a temperature of about 25°

C. and a pressure difference of 50 bar.

27. A flexible pipe according to claim 22 wherein the film layer is essentially impermeable to methane at a partial pressure of at least 1 bar at a temperature of about 25°

C. and a pressure difference of 50 bar.

28. A flexible pipe according to claim 22 wherein the film layer is essentially impermeable to carbon dioxide, at a partial pressure of at least 1 bar at a temperature of about 25°

C. and a pressure difference of 50 bar.

29. A flexible pipe according to claim 1 wherein said film layer is the innermost layer of said film layer and said polymer layer.

30. A flexible pipe according to claim 1 wherein said film layer is sandwiched between two polymer layers, at least one of the polymer layers being bonded to the film layer, with a bonding that is stronger than the internal cohesion of said polymer layer.

31. A flexible pipe according to claim 30 wherein the innermost polymer layer of the two polymer layers is selected from the group consisting of polyolefins;

polyamide;

polyimide (PI);

polyurethanes;

polyureas;

polyesters;

polyacetals;

polyethers;

polyoxides;

polysulfides;

polysulphones;

polyacrylates;

polyethylene terephthalate (PET);

polyether-ether-ketones (PEEK);

polyvinyls;

polyacrylonitrils;

polyetherketoneketone (PEKK);

copolymers of the preceding and fluorous polymers.

32. A flexible pipe according to claim 31 wherein the innermost polymer layer of the two polymer layers being PVDF and the polymer layer on the in radial direction outermost of the two polymer layer is cross-linked polyethylene (XLPE).

33. A flexible pipe according to claim 31 wherein the innermost polymer layer of the two polymer layers is cross-linked polyethylene (XLPE).

34. A flexible pipe according to claim 1 wherein the film layer is in the form of a tape wound around an innermost polymer layer.

35. A flexible pipe according to claim 1 wherein the film layer is in the form of a tape folded around an innermost polymer layer.

36. A flexible pipe according to claim 1 wherein said film layer comprises C atoms, the polymer being a cross-linked polymer with bondings linking to the C atoms of the film layer.

37. A flexible pipe according to claim 1 wherein said pipe comprises one or more innermost unbonded armouring layers (carcass).

38. A flexible pipe according to claim 1 wherein said pipe comprises at least one unbonded armouring layer on the outer side of the polymer layer bonded to said film layer.

39. A method of producing a flexible unbonded pipe as defined in claim 1, said method comprises the steps of providing at least one polymer layer and at least one film layer and bonding said layers to each other.

40. A method according to claim 39 said method comprises the steps of

providing an innermost polymer layer using a method selected from extrusion, winding, or wrapping,

providing a film layer around said innermost polymer layer using a method selected from extrusion, winding, or wrapping,

providing a second polymer layer around said film layer, and

providing a bonding between at least one of said polymer layers and said film layer.

41. A method according to claim 39 said method comprising the steps of

providing a film layer around a mandrel or an inner armour layer (carcass), using a method selected from extrusion, winding and wrapping,

providing a polymer layer around said film layer by extrusion, and

providing a bonding between said polymer layer and said film layer.

42. A method according to claim 39, said method comprising the steps of

providing an innermost layered section of the flexible pipe comprising at least an innermost polymer layer and an armour layer on the outer side of said innermost polymer layer,

providing a film layer around said innermost layered section of the flexible pipe,

providing an outer polymer layer around said film layer, and

providing a bonding between at least one of said polymer layers and said film layer.

43. A method according to claim 39 wherein the film layer is treated by corona or by application of a primer for increasing bonding strength.

44. A method according to claim 39 wherein the film layer or a primer coated onto said film layer comprises C atoms.

46. A method according to claim 39 wherein the film layer comprises a metal tape with a primer.

47. A method according to claim 40 wherein said bonding is provided by subjecting said at least one polymer layer to cross-linking.

48. A method according to claim 42 wherein said bonding is provided by cross-linking of said polymer layer.

49. A method according to claim 42 wherein said bonding is provided by subjecting said polymer layer to cross-linking.

45. (canceled)

50. A flexible unbonded pipe, said pipe comprising at least one polymer layer and at least one film layer, said film layer being a metal film layer and said polymer layer being bonded to said film layer.

52. a flexible unbonded pipe according to claim 50, wherein the bonding between the polymer layer and the film layer has a peel strength using ASTM D3330 of at least 300 N/m.

51. A flexible unbonded pipe, said pipe comprising at least one polymer layer and at least one film layer, said polymer layer being bonded to said film layer, and the interfacial bonding between the polymer layer and the film layer being sufficiently strong to prevent creation of gas pockets between the layers when subjected to an increased carbon dioxide pressure of 5 bar on the film side of the pipe.

53. A flexible unbonded pipe, said pipe comprising at least one polymer layer and at least one film layer, said polymer layer being thicker than said film layer, said film layer being a wounded or folded film layer, and said polymer layer being bonded to said film layer.

54. A flexible unbonded pipe, said pipe comprising at least one polymer layer and at least one film layer, said polymer layer being a cross-linked polyethylene and said polymer layer being bonded to said film layer, and said bondings being established by the cross-linking of the polyethylene.