THERMOPLASTIC COMPOSITE

Abstract

A method of making a flexible pipe layer, which method comprises: commingling polymer filaments and carbon fibre filaments to form an intimate mixture, forming yarns of the commingled filaments, forming the yarns into a tape, and applying the tape to a pipe body to form a flexible pipe layer.

Claims

1. A flexible pipe, comprising: a pipe layer that comprises: a first region characterized by a thermoplastic composite comprising a polymer and carbon fibre, wherein carbon fibre is present in a first concentration, and a second region characterized by one or more of: a thermoplastic composite comprising a polymer and carbon fibre, wherein carbon fibre is present in a second concentration; and a polymer composition.

2. The flexible pipe of claim 1, wherein the first concentration of carbon fibre and the second concentration of carbon fibre are set by an application of tapes respectively to the first region and the second region.

3. The flexible pipe of claim 1, wherein the polymer is a fluoropolymer having a melt flow index (230° C./2.16 kg) in the range of 50 to 80 g/10 min wherein the fluoropolymer is selected from at least one of perfluoroalkoxy alkanes (PFA), poly(ethene-co-tetrafluoroethene) (ETFE), polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP) and polyvinylidene fluoride (PVDF).

4. The flexible pipe of claim 1, wherein the polymer is a fluoropolymer having a melt flow index (230° C./2.16 kg) in the range of 60 to 70 g/10 min, wherein the fluoropolymer is selected from at least one of perfluoroalkoxy alkanes (PFA), poly(ethene-co-tetrafluoroethene) (ETFE), polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP) and polyvinylidene fluoride (PVDF).

5. The flexible pipe of claim 1, wherein the carbon fibre has a tow size of 3000 to 12000.

6. The flexible pipe of claim 1, wherein the polymer is poly-ether-ether-ketone (PEEK) or polyamide (PA-11 or PA-12).

7. The flexible pipe of claim 1, wherein the polymer is present in an amount of 30 to 70 weight % of the total weight of the polymer and carbon fibre in either the first region, or the second region, or both of the first and second region.

8. The flexible pipe of claim 1, wherein the pipe layer comprises a pressure armour layer positioned adjacent to, or bonded to, a tubular polymer layer.

9. The flexible pipe of claim 8, wherein the tubular polymer layer is disposed on an inside portion of the pressure armour layer and is configured as a fluid barrier layer.

10. A method of manufacturing a flexible pipe layer, the method comprising: commingling polymer filaments and carbon fibre filaments to form an intimate mixture; forming yarns from the intimate mixture; forming tape from the yarns; and forming a flexible pipe layer by applying the tape to a pipe body.

11. The method of claim 10, wherein commingling the polymer filaments and carbon fibre filaments comprises applying a compressed gas to the polymer filaments and carbon fibre filaments to form the intimate mixture of the filaments.

12. The method of claim 10, wherein commingling the polymer filaments and carbon fibre filaments comprises applying a series of combs to the polymer filaments and carbon fibre filaments to form the intimate mixture of the filaments.

13. The method of claim 10, wherein forming the tape from the yarns comprises compressing or extruding one or more of the filaments and the yarns.

14. The method of claim 10, further comprising: arranging a first region of filaments or yarns having a first concentration of carbon fibre adjacent to a second region of filaments or yarns having a second concentration of carbon fibre; and compressing or extruding one or more of the filaments and the yarns to form a tape, wherein the tape is characterized by a first region having a first concentration of carbon fibre, and a second region having a second concentration of carbon fibre.

15. The method of claim 10, further comprising; arranging a first region of filaments or yarns that contain carbon fibre adjacent to a second region of filaments or yarns consisting essentially of polymer; and compressing or extruding the filaments or yarns to form a tape, wherein the tape is characterized by a first region containing carbon fibre, and a second region consisting essentially of polymer.

16. The method of claim 10, further comprising: arranging a first plurality of filaments or yarns having a first concentration of carbon fibre, the arranging comprising: commingling polymer filaments and carbon fibre filaments to form a first intimate mixture, forming first yarns from the first intimate mixture, compressing or extruding first yarns to form a first tape, wherein the first tape is characterized by a first concentration of carbon fibre, and arranging a second plurality of filaments or yarns having a second concentration of carbon fibre, the arranging comprising: commingling polymer filaments and carbon fibre filaments to form a second intimate mixture, forming second yarns from the second intimate mixture, compressing or extruding the second yarns to form a second tape, wherein the second tape is characterized by a second concentration of carbon fibre, and applying predetermined amounts of the first tape and the second tape to a pipe body to form a flexible pipe layer.

17. The method of claim 10, further comprising wrapping the tape around a pipe body, and heating the wrapped tape so that the polymer filaments melt around the carbon filaments to form a polymer matrix.

18. The method of claim 10, wherein the polymer filaments comprise a fluoropolymer, and wherein the polymer has a melt flow index (230° C./2.16 kg) in the range of 50 to 80 g/10 min.

19. The method of claim 10, wherein the polymer filaments comprise a fluoropolymer, and wherein the polymer has a melt flow index (230° C./2.16 kg) in the range of 60 to 70 g/10 min.

20. The method of claim 10, further comprising forming a pressure armour layer on the pipe body.

Description

LISTING OF FIGURES

[0039] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

[0040] FIG. 1 illustrates a flexible pipe body; and

[0041] FIG. 2 illustrates a riser, flowline and jumper.

[0042] In the drawings like reference numerals refer to like parts.

DETAILED DESCRIPTION

[0043] Throughout this description, reference will be made to a flexible pipe. It will be understood that a flexible pipe is an assembly of a portion of pipe body and one or more end fittings in each of which a respective end of the pipe body is terminated. FIG. 1 illustrates how pipe body 100 is formed in accordance with an embodiment of the present invention from a combination of layered materials that form a pressure-containing conduit. Although a number of particular layers are illustrated in FIG. 1, it is to be understood that the present invention is broadly applicable to coaxial pipe body structures including two or more layers manufactured from a variety of possible materials. For example, the pipe body may be formed from polymer layers, metallic layers, composite layers, or a combination of different materials. It is to be further noted that the layer thicknesses are shown for illustrative purposes only.

[0044] As illustrated in FIG. 1, a pipe body includes an optional innermost carcass layer 101. The carcass provides an interlocked construction that can be used as the innermost layer to prevent, totally or partially, collapse of an internal pressure sheath 102 due to pipe decompression, external pressure, and tensile armour pressure and mechanical crushing loads. The carcass layer is often a metallic layer, formed from stainless steel, for example. The carcass layer could also be formed from composite, polymer, or other material, or a combination of materials. It will be appreciated that certain embodiments of the present invention are applicable to ‘smooth bore’ operations (i.e. without a carcass layer) as well as such ‘rough bore’ applications (with a carcass layer).

[0045] The internal pressure sheath 102 acts as a fluid retaining layer and comprises a polymer layer that ensures internal fluid integrity. It is to be understood that this layer may itself comprise a number of sub-layers. It will be appreciated that when the optional carcass layer is utilised the internal pressure sheath is often referred to by those skilled in the art as a barrier layer. In operation without such a carcass (so-called smooth bore operation) the internal pressure sheath may be referred to as a liner.

[0046] A pressure armour layer 103 is a structural layer that increases the resistance of the flexible pipe to internal and external pressure and mechanical crushing loads. The layer also structurally supports the internal pressure sheath. In a preferred embodiment, the pressure armour layer 103 is formed from the thermoplastic composite described herein.

[0047] The flexible pipe body also includes an optional first tensile armour layer 105 and optional second tensile armour layer 106. Each tensile armour layer is used to sustain tensile loads and internal pressure. The tensile armour layer is often formed from a plurality of (e.g. metallic) wires (to impart strength to the layer) that are located over an inner layer and are helically wound along the length of the pipe at a lay angle typically between about 10° to 55°. The tensile armour layers are often counter-wound in pairs. The tensile armour layers are often metallic layers, formed from carbon steel, for example. The tensile armour layers could also be formed from composite, polymer, or other material, or a combination of materials.

[0048] The flexible pipe body shown also includes optional layers of tape 104 which help contain underlying layers and to some extent prevent abrasion between adjacent layers, or indeed as an outer surface of the flexible pipe in areas which may experience abrasion during service. The tape layer may be a polymer or composite or a combination of materials. The tape layer 104 may be formed of the thermoplastic composite described herein.

[0049] The flexible pipe body also typically includes optional layers of insulation 107 and an outer sheath 108, which comprises a polymer layer used to protect the pipe against penetration of seawater and other external environments, corrosion, abrasion and mechanical damage.

[0050] Each flexible pipe comprises at least one portion, sometimes referred to as a segment or section of pipe body 100 together with an end fitting located at at least one end of the flexible pipe. An end fitting provides a mechanical device which forms the transition between the flexible pipe body and a connector. The different pipe layers as shown, for example, in FIG. 1 are terminated in the end fitting in such a way as to transfer the load between the flexible pipe and the connector.

[0051] FIG. 2 illustrates a riser assembly 200 suitable for transporting production fluid such as oil and/or gas and/or water from a sub-sea location 201 to a floating facility. For example, in FIG. 2 the sub-sea location 201 includes a sub-sea flow line. The flexible flow line 205 comprises a flexible pipe, wholly or in part, resting on the sea floor 204 or buried below the sea floor and used in a static application. The floating facility may be provided by a platform and/or buoy or, as illustrated in FIG. 2, a ship 200. The riser assembly 200 is provided as a flexible riser, that is to say a flexible pipe 203 connecting the ship to the sea floor installation. The flexible pipe may be in segments of flexible pipe body with connecting end fittings.

[0052] It will be appreciated that there are different types of riser, as is well-known by those skilled in the art. Embodiments of the present invention may be used with any type of riser, such as a freely suspended (free, catenary riser), a riser restrained to some extent (buoys, chains), totally restrained riser or enclosed in a tube (I or J tubes).

[0053] FIG. 2 also illustrates how portions of flexible pipe can be utilised as a flow line 205 or jumper 206.

[0054] It will be clear to a person skilled in the art that features described in relation to any of the embodiments described above can be applicable interchangeably between the different embodiments. The embodiments described above are examples to illustrate various features of the invention.

[0055] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0056] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0057] The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.