Flexible pipe sealing

Abstract

The present invention relates to an end-fitting for joining to a pipe body, a flexible pipe including such an end-fitting and a pipe body, and a method of assembling a flexible pipe. The end-fitting comprises: a sleeve comprising: a first section partially insertable radially inwardly of a polymer layer of the pipe body; and a second section; an annular polymer extension connectable to the pipe body, the annular polymer extension partially disposed radially outwardly of the first section of the sleeve and disposed radially outwardly of the second section of the sleeve; and a recess disposed between the second section of the sleeve and the annular polymer extension, for receiving a seal to prevent fluid ingress between the second section of the sleeve and the annular polymer extension.

Description

[0001] FLEXIBLE PIPE SEALING

[0002] The present invention relates to a flexible pipe sealing. In particular, but not exclusively, the present invention relates to an end-fitting for joining to a pipe body, a flexible pipe including 5 such an end-fitting and a pipe body, and a method of assembling a flexible pipe.

[0003] Traditionally flexible pipe is utilised to transport production fluids, such as oil and / or gas and / or water, from one location to another. Flexible pipe is particularly useful in connecting a sub-sea location (which may be deep underwater) to a sea level location. The pipe may 10 have an internal diameter of typically up to around 0.6 metres (e.g., diameters may range from 0.05 m up to 0.6 m). Flexible pipe is generally formed as an assembly of a flexible pipe body and one or more end-fittings. The pipe body is typically formed as a combination of layered materials that form a pressure-containing conduit. The pipe structure allows large deflections without causing bending stresses that impair the pipe’s functionality over its

[0004] 15 lifetime. The pipe body is generally built up as a combined structure including polymer, and / or metallic, and / or composite layers. For example, a pipe body may include polymer and metal layers, or polymer and composite layers, or polymer, metal and composite layers.

[0005] API Recommended Practice 17B provides guidelines for the design, analysis, manufacture, 20 testing, installation, and operation of flexible pipes and flexible pipe systems for onshore, subsea and marine applications, and API Specification 17J titled “Specification for Unbonded Flexible Pipe” defines the technical requirements for safe, dimensionally and functionally interchangeable flexible pipes that are designed and manufactured to uniform standards and criteria.

[0006] 25

[0007] Unbonded flexible pipe has been used for deep-water (less than 3,300 feet (1 ,005.84 metres)) and ultra deep-water (greater than 3,300 feet) developments. It is the increasing demand for oil which is causing exploration to occur at greater and greater depths where environmental factors are more extreme. For example, in such deep and ultra deep-water 30 environments, ocean floor temperature increases the risk of production fluids cooling to a temperature that may lead to pipe blockage. Increased depths also increase the pressure associated with the environment in which the flexible pipe must operate. For example, a flexible pipe may be required to operate with external pressures ranging from 0.1 MPa to 30 MPa acting on the pipe. Equally, transporting oil, gas or water may well give rise to high 35 pressures acting on the flexible pipe from within, for example, with internal pressures ranging from 0 MPa to 140 MPa from bore fluid acting on the pipe. As a result, the need for high levels of performance from the layers of the flexible pipe body is increased.

[0008] 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 a 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 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 pipe body is broadly applicable to coaxial 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. As used herein, the term “composite” is used to broadly refer to a material that is formed from two or more different materials, for example a material formed from a matrix material and reinforcement fibres.

[0009] 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 are applicable to ‘smooth bore’ operations (i.e. , without a carcass layer) as well as such ‘rough bore’ applications (i.e., with a carcass layer).

[0010] The internal pressure sheath 102 acts as a fluid retaining layer and includes a polymer layer that ensures internal fluid integrity. It is to be understood that this layer may itself include 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. An optional 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, and typically may be formed from an interlocked construction of wires wound with a lay angle close to 90°. The pressure armour layer is often a metallic layer, formed from carbon steel, for example. The pressure armour layer could also be formed from composite, polymer, or other material, or a combination of materials.

[0011] 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 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.

[0012] 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. The tape layer may be a polymer, or composite, or a combination of materials.

[0013] The flexible pipe body also typically includes optional layers of insulation 107. The pipe body includes an outer sheath 108, which includes a polymer layer used to protect the pipe against penetration of seawater and other external environments, corrosion, abrasion and mechanical damage.

[0014] Each flexible pipe includes 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. The end-fittings of a flexible pipe may be used for connecting segments of flexible pipe body together or for connecting them to terminal equipment such as a rigid sub-sea structures or floating facilities. As such, amongst other varied uses, flexible pipe can be used to provide a riser assembly for transporting fluids from a sub-sea flow line to a floating structure. In such a riser assembly, a first segment of flexible pipe may be connected to one or more further segments of flexible pipe. Each segment of flexible pipe includes at least one endfitting.

[0015] 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 includes 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. It will be appreciated that there are different types of risers, as is well-known by those skilled in the art. Embodiments 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). Fig. 2 also illustrates how portions of flexible pipe can be utilised as a flow line 205 or jumper 206.

[0016] A cross-section of a known end-fitting assembly 300, such as that disclosed in WO2007 / 144552 or EP1867907, is shown in Fig. 3. The end-fitting 300 includes an endfitting body 301 , which includes an internal bore 302 running along its length. The end-fitting body is made from steel or other such rigid material. At a first end of the end-fitting body 301 there is defined an open mouth region 303 into which an end of a segment of flexible pipe body 100 is located and then terminated. At a further end of the end-fitting body 301 is a connector 304. This is formed as a substantially disk-like flared region on the end-fitting body. The connector can be connected directly to a matching connector of a further endfitting body of an adjacent segment of flexible pipe body. This can be done using bolts or some other form of securing mechanism. In such a configuration the end-fittings would be located in a back-to-back configuration. Alternatively, the connector 304 may be connected to a floating or stationary structure such as a ship, platform or other such structure. Various layers of flexible pipe body are introduced to the end-fitting assembly, cut to appropriate length, and sealingly engaged with a particular portion of the end-fitting. The end-fitting 300 includes a jacket 307, which is connected to the end-fitting body 301 such that a cavity 313 is formed between the jacket 307 and the end-fitting body 301. Ends 112 of at least one of the various layers of the flexible pipe body 100 are terminated and secured within said cavity 313.

[0017] It is well-known that there are many varied problems associated with the provision of endfittings for ends of a flexible pipe body. The end-fittings must ensure both good fastening and good sealing. There is a need to seal the bore of the flexible pipe body with the bore of the end-fitting. Particular problems occur when the various specific layers of the multi-layer flexible pipe body are terminated. The flexible pipe body may include layers having different material characteristics, for example single polymer layers and / or interlocked metallic layers. The termination of each of these layers in an end-fitting brings with it characteristic problems. For example, a flexible pipe body typically includes a fluid-retaining layer (known as a barrier layer or liner) formed generally as a polymer sheath or pressure sheath. Such a layer operates as a primary fluid retaining layer. The fluid-retaining layer must connect with an end-fitting, ensuring a full seal to maintain fluid within the bore of the flexible pipe, while parameters such as internal fluid pressure, external hydrostatic pressure and movement from subsea motion make maintaining the seal more difficult.

[0018] It is an aim of the present invention to at least partly mitigate the above-mentioned problems.

[0019] According to a first aspect of the present invention there is provided an end-fitting comprising: a sleeve comprising: a first section partially insertable radially inwardly of a polymer layer of the pipe body; and a second section; an annular polymer extension connectable to the pipe body, the annular polymer extension partially disposed radially outwardly of the first section of the sleeve and disposed radially outwardly of the second section of the sleeve; and a recess disposed between the second section of the sleeve and the annular polymer extension, for receiving a seal to prevent fluid ingress between the second section of the sleeve and the annular polymer extension.

[0020] Suitably, the end-fitting comprises the seal in the recess. Suitably, the seal comprises a complimentary profile to the recess.

[0021] Suitably, the seal is energised, in use, such that the seal is swaged against an external surface of the second section of the sleeve.

[0022] Suitably, an external surface of the second section of the sleeve comprises a tapered section, such that the recess comprises a tapered profile.

[0023] Suitably, the end-fitting comprises a body comprising: a first section partially disposable radially outwardly of the polymer layer of the pipe body; and a second section disposed radially outwardly of the annular polymer extension of the end-fitting, the second section of the body having a complimentary profile to an external surface of the annular polymer extension of the end-fitting.

[0024] Suitably, the body comprises a further recess disposed between the first section of the body and the polymer layer of the pipe body, in use, and suitably, the end-fitting comprises a further seal configurable to be located in the further recess, to prevent fluid ingress between the first section of the body and the polymer layer of the pipe body.

[0025] Suitably, the end-fitting comprises a collar affixed to an end of the first section of the body, and suitably, the collar is configured to energise the further seal, in use, such that the further seal is swaged against an internal surface of the first section of the body.

[0026] Suitably, the end-fitting comprises a further collar affixed to an end of the second section of the body, and suitably, the further collar is configured to energise the seal, in use, such that the seal is swaged against the external surface of the second section of the sleeve.

[0027] Suitably, the annular polymer extension of the end-fitting comprises a polyamide.

[0028] Suitably, the annular polymer extension is configured to be connectable to the polymer layer of the pipe body. Suitably, the annular polymer extension is configured to be weldable to the polymer layer of the pipe body.

[0029] According to a second aspect of the present invention there is provided a flexible pipe

[0030] 5 comprising: a pipe body comprising a polymer layer; and an end-fitting comprising: a sleeve comprising: a first section partially inserted radially inwardly of the polymer layer of the pipe body; and a second section; an annular polymer extension connectable to the pipe body, the annular polymer extension partially disposed radially outwardly of the first section of the sleeve and disposed radially outwardly of the second section of the sleeve; and a recess

[0031] 10 disposed between the second section of the sleeve and the annular polymer extension, for receiving a seal to prevent fluid ingress between the second section of the sleeve and the annular polymer extension.

[0032] According to a third aspect of the present invention there is provided a method comprising:

[0033] 15 providing a pipe body comprising a polymer layer; providing a sleeve of an end-fitting comprising: a first section; and a second section; providing an annular polymer extension connectable to the pipe body, the annular polymer extension partially disposed radially outwardly of the first section of the sleeve and disposed radially outwardly of the second section of the sleeve; providing a recess of the end-fitting and disposing the recess between

[0034] 20 the second section of the sleeve and the annular polymer extension; and partially inserting the first section of the sleeve radially inwardly of the polymer layer of the pipe body.

[0035] Suitably, the method comprises providing a seal of the end-fitting and locating the seal in the recess, the seal configured to prevent fluid ingress between the second section of the

[0036] 25 sleeve and the annular polymer extension.

[0037] Suitably, the method comprises energising the seal such that the seal is swaged against an external surface of the second section of the sleeve.

[0038] 30 Suitably, the method comprises connecting the annular polymer extension to the pipe body.

[0039] Suitably, the method comprises connecting the annular polymer extension to the polymer layer of the pipe body. Suitably, the method comprises welding the annular polymer extension to the polymer layer of the pipe body.

[0040] Certain embodiments of the invention give the advantage of an improved connection between an end-fitting and a pipe body. Certain embodiments provide an arrangement in which welding of a metallic component of the end-fitting to the pipe body is avoided. Certain embodiments provide the effect of a reduction in polymer creep, resulting in an improved seal between components of the end-fitting, particularly at deep-water and / or ultra deepwater pressures. For example, by locating a seal radially inwardly of a polymer section, an external hydrostatic pressure will help continually urge the polymer section onto the seal, thereby maintaining a good sealing effect.

[0041] Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

[0042] Fig. 1 illustrates an example pipe body;

[0043] Fig. 2 illustrates a riser assembly;

[0044] Fig. 3 illustrates an example end-fitting;

[0045] Fig. 4 illustrates an end-fitting of a flexible pipe according to an embodiment of the invention;

[0046] Fig. 5 illustrates the end-fitting of Fig. 4 including a body;

[0047] Fig. 6 illustrates the end-fitting of Fig. 5 including a first seal;

[0048] Fig. 7 illustrates the end-fitting of Fig. 6 including a first collar;

[0049] Fig. 8 illustrates the end-fitting of Fig. 7 including a second seal;

[0050] Fig. 9 illustrates the end-fitting of Fig. 8 including a second collar;

[0051] Fig. 10 illustrates the end-fitting of Fig. 9 including a jacket;

[0052] Fig. 1 1 a illustrates a further end-fitting of a flexible pipe according to an embodiment of the invention, the further end-fitting including a sealing assembly;

[0053] Fig. 11 b illustrates the sealing assembly of the further end-fitting of Fig. 11 a;

[0054] Fig. 12a illustrates a further end-fitting of a flexible pipe according to an embodiment of the invention, the further end-fitting including a further sealing assembly;

[0055] 8

[0056] SUBSTITUTE SHEET (RULE 26) Fig. 12b illustrates the further sealing assembly of the further end-fitting of Fig. 12a;

[0057] Fig. 13 illustrates a further end-fitting of a flexible pipe according to an embodiment of the invention, the further end-fitting including a third seal;

[0058] Fig. 14a illustrates a method of assembling a flexible pipe according to an embodiment of the invention; and

[0059] Fig. 14b illustrates a further method of assembling a flexible pipe according to an embodiment of the invention.

[0060] In the drawings, like reference numerals refer to like parts.

[0061] Fig. 4 to 10 illustrate sequential stages in assembling a flexible pipe.

[0062] Fig. 4 illustrates an end-fitting 400 of a flexible pipe 1000 according to an embodiment of the invention.

[0063] The end-fitting 400 includes a sleeve 402. The sleeve 402 supports a polymer layer 504 of a pipe body 500 and provides an external surface to dispose an annular polymer extension 436 of the end-fitting 400 thereon, such that the end-fitting 400 is connectable to the pipe body 500. The sleeve 402 is substantially tubular such that the sleeve 402 includes a bore suitable to enable fluid flow therethrough, for example, oil or water. Aptly, the polymer layer 504 is an outer sheath of the pipe body 500.

[0064] The sleeve 402 includes a first section 418a and a second section 418b. The first section 418a is disposed adjacent to the second section 418b. The first section 418a is disposed on a first side of transverse axis 494, and the second section 418b is disposed on a second side of transverse axis 494. The sleeve 402 is unitary in construction. The sleeve 402 is formed of metal. In this case, the sleeve 402 is formed of stainless steel. The sleeve 402 may aptly be formed of carbon steel or alloy steel. The sleeve 402 may be formed of aluminium, or titanium, or nickel alloy. The sleeve 402 may optionally be coated with a low friction coating to aid insertion radially beneath a terminal end of the polymer layer 504. The first section 418a is partially inserted radially inwardly of the polymer layer 504 of the pipe body 500. In this way, the first section 418a provides a transition pathway between the pipe body 500 and the second section 418b of the sleeve 402. The first section 418a aptly has a complimentary profile to an internal surface of the polymer layer 504. Aptly, the internal diameter of the first section 418a is substantially equal to the internal diameter of the polymer layer 504, and the polymer layer 504 must be stretched to receive the sleeve 402, during insertion. Optionally, the external diameter of the first section 418a is substantially equal to the internal diameter of the polymer layer 504. The first section 418a is disposed radially adjacent to the polymer layer 504, such that the polymer layer 504 and the first section 418a are in contact with one another. The first section 418a supports an internal surface of the polymer layer 504, such that underlying layers of the pipe body 500 pass through the bore of the sleeve 402 and are connected to, or between, other components of the end-fitting 400 (not shown here for simplicity). A first end 468 of the sleeve 402 (more specifically, an end of the first section 418a) includes a tapered portion 496 configured to facilitate partially inserting the first section 418a radially inwardly of the polymer layer 504.

[0065] The second section 418b extends away from the polymer layer 504. The second section 418b has an external diameter larger the external diameter of the first section 418a. An external surface 434 of the second section 418b has a tapered section 424. The tapered section 424 tapers from a larger diameter to a smaller diameter in a direction moving away from the first section 418a. In other words, the tapered section 424 has first end 426a at a position along the external surface 434 of the second section 418b and a second end 426b disposed at an end of the sleeve 402, and the external diameter at the first end 426a of the tapered section 424 is greater than the external diameter at the second end 426b of the tapered section 424. Aptly, as shown in Fig. 4, the tapered section 424 tapers non-linearly. Optionally, the tapered section 424 includes a portion that is orientated perpendicular to a central, longitudinal axis 432 of the end-fitting 400. Aptly, the tapered section 424 comprises a sealing surface configured to engage with an opposing sealing surface of a seal ring (see second seal 404, as described later, in relation to Fig. 8). The internal diameter of the second section 418b is at least partially equal to the internal diameter of the first section 418a, such that the bore of the sleeve 402 is continuous. The second section 418b includes a receiving portion 484 for receiving a second collar 412 of the end-fitting 400 (as described later, in relation to Fig. 9). The internal diameter of the receiving portion 484 may be greater than the internal diameter of the first section 418a. The end-fitting 400 includes an annular polymer extension 436. The annular polymer extension 436 is provided radially outwardly of the sleeve 402 and is connectable (e.g., welded) to the polymer layer 504 of the pipe body 500, such that the end-fitting 400 is connected to the pipe body 500. The annular polymer extension 436 effectively extends the polymer layer 504 into the end-fitting 400, and allows for a variation in the shaping of the polymer layer 504, to suit the adjacent parts of the end-fitting 400 that the polymer layer 504 couples with. Polymer welding may be used to connect the terminal end of the polymer layer 504 with the annular polymer extension 436, using known techniques, equipment, and a suitable, compatible filler material, and providing a full circumference annular connection between the polymer layer 504 and the annular polymer extension 436. Aptly, the polymer weld filler material is the same polymer as the polymer layer 504, which is also the same as the polymer of the annular polymer extension 436. Aptly, the polymers of the polymer layer 504, the weld filler material, and the annular polymer extension 436 are different but are compatible (i.e. , fusible together using known welding techniques).

[0066] The annular polymer extension 436 is partly or fully disposed radially outwardly of the second section 418b of the sleeve 402, and is partially disposed radially outwardly of the first section 418a of the sleeve 402. The annular polymer extension 436 is formed of a polymer material. In this case, the annular polymer extension 436 is formed of a polyamide. Aptly, the polyamide is polyamide 12. Aptly, the polyamide is polyamide 11. Optionally, the material of the annular polymer extension 436 is a polyethylene, a polypropylene, or a thermoplastic elastomer.

[0067] The annular polymer extension 436 has a complimentary profile to an external surface of the first section 418a. The internal diameter of the annular polymer extension 436 is substantially equal to the external diameter of the first section 418a. Aptly, the annular polymer extension 436 is disposed radially adjacent to the first section 418a, such that the annular polymer extension 436 and the first section 418a are in contact with one another. As shown in Fig. 4, the annular polymer extension 436 includes a portion 487 that extends in a radial direction away from a central, longitudinal axis 432 of the end-fitting 400. The portion 487 of the annular polymer extension 436 has a complimentary profile to an external, side surface of the second section 418b. In this case, the overall shape of the annular polymer extension 436 can be said to be annular and include a ‘dog-leg’ widened portion (i.e., a portion with a greater diameter) that extends over the second section 418b of the sleeve 402. The annular polymer extension 436 is connected to the polymer layer 504, such that the pipe body 500 and the end-fitting 400 are connected to one another. The annular polymer extension 436 is welded to the polymer layer 504. More specifically, an end of the annular polymer extension 436 is welded to an end of the polymer layer 504. The annular polymer 5 extension 436 and the polymer layer 504 include tapered portions to facilitate welding the annular polymer extension 436 and the polymer layer 504 to one another. Aptly, the thickness of the annular polymer extension 436 is substantially equal to the thickness of the polymer layer 504.

[0068] 10 The end-fitting 400 includes a recess 430. The recess 430 is configured to receive a second seal 404 of the end-fitting 400, the second seal 404 configured to prevent fluid ingress between the second section 418b of the sleeve 402 and the annular polymer extension 436 (as described later, in relation to Fig. 8).

[0069] 15 The recess 430 disposed between the second section 418b of the sleeve 402 and the annular polymer extension 436. More specifically, the recess 430 is disposed between the tapered section 424 of the second section 418b and the annular polymer extension 436, such that the recess 430 has an at least partly tapered profile. The recess 430 is annular.

[0070] 20 Fig. 5 illustrates the end-fitting 400 of Fig. 4 including a body 408.

[0071] The end-fitting 400 includes a body 408. The body 408 is provided as part of the end-fitting 400 that lays outwardly of, and thereby protects, the polymer sections of the end-fitting 400 and the pipe body 500 (i.e. , the annular polymer extension 436 and the polymer layer 504, 25 and the connection between). The body 408 is further configured to allow a connection to a jacket 416 (as described later, in relation to Fig. 10), and further elements of the end-fitting 400.

[0072] The body 408 includes a first section 444a and a second section 444b. The first section 30 444a is disposed adjacent to the second section 444b. The first section 444a is disposed on a first side of transverse axis 498, and the second section 444b is disposed on a second side of transverse axis 498. The first section 444a of the body 408 is partially disposed radially outwardly of the polymer layer 504 of the pipe body 500, and the second section 444b is disposed radially outwardly of the annular polymer extension 436. The body 408 is unitary in construction. The body 408 is formed of metal. In this case, the body 408 is formed of stainless steel. Aptly, the body 408 is made of carbon or alloy steel. Aptly, the body 408 is made of aluminium, or titanium alloy. Optionally, the body 408 may be at least partly coated with a suitable corrosion protection coating system, such as an epoxy-based coating.

[0073] An internal surface 447 of the first section 444a has a tapered section 446. The tapered section 446 tapers from a larger diameter to a smaller diameter in a direction moving away from an end 452 of the body 408. In other words, the tapered section 446 has a first end 453 at the end 452 of the body 408 (more specifically, an end of the first section 444a of the body 408), and a second end 455 at a position along the length of the internal surface 447, and the internal diameter at the first end 453 is greater than an internal diameter at the second end 455. As shown in Fig. 5, the tapered section 446 tapers non-linearly. The tapered section 446 includes a portion that is orientated perpendicular to a central, longitudinal axis 432 of the end-fitting 400. Aptly, the tapered section 446 comprises a sealing surface configured to engage with an opposing sealing surface of a seal ring (see first seal 410, as described later, in relation to Fig. 6).

[0074] The end-fitting 400 includes a further recess 448. The further recess 448 is configured to receive a first seal 410 of the end-fitting 400, the first seal 410 configured to prevent fluid ingress between the first section 444a of the body 408 and the polymer layer 504 (as described later, in relation to Fig. 6).

[0075] The further recess 448 is disposed between the first section 444a and the polymer layer 504. More specifically, the further recess 448 is disposed between the tapered section 446 of the internal surface 447 of the first section 444a and the polymer layer 504, such that the further recess 448 has a tapered profile. The further recess 448 is annular.

[0076] The first section 444a includes a receiving portion 492a for receiving a fixing 450 (e.g., a bolt) configured to join a first collar 414 of the end-fitting 400 to the first section 444a of the body 408 (as described later, in relation to Fig. 7). The receiving portion 492a is disposed radially outwardly of the further recess 448. As shown in Fig. 5, in this case, the receiving portion 492a is disposed at at least two points around the circumference of the second section 444a. As such, a plurality of fixings can be used to join the body 408 with the first collar 414. The second section 444b of the body 408 has a complimentary profile to an external surface of the annular polymer extension 436. The internal diameter of the second section 444b is substantially equal to the external diameter of the annular polymer extension 436. The second section 444b is disposed radially adjacent to the annular polymer extension 436, such that the annular polymer extension 436 and the second section 444b are in contact with one another.

[0077] The second section 444b of the body 408 includes a receiving portion 492b for receiving a second collar 412 (as described later, in relation to Fig. 9). The receiving portion 492b is disposed at a further end 456 of the body 408 (more specifically, an end of the second section 444b of the body 408). The receiving portion 492b includes an O-ring disposed around a circumference of the receiving portion 492b. The second section 444b includes a further receiving portion 492c for receiving a fixing 454 (e.g., a bolt) configured to join a second collar 412 of the end-fitting 400 to the second section 444b of the body 408 (as described later, in relation to Fig. 9). As shown in Fig. 5, in this case, the further receiving portion 492c is disposed at at least two points around the circumference of the second section 444b. As such, a plurality of fixings can be used to join the body 408 with the second collar 412.

[0078] Fig. 6 illustrates the end-fitting 400 of Fig. 5 including a first seal 410.

[0079] The end-fitting 400 includes a first seal 410. The first seal 410 is configured to be energised, in use, such that fluid ingress between the first section 444a of the body 408 and the polymer layer 504 is prevented. Also, the portion of the polymer layer 504 inside the end fitting 400 (i.e., that beyond the first seal 410) is isolated from forces or stress loading present in the polymer layer 504 outside of the end fitting 400, as a result of tension or bending of the pipe body 500. Preventing fluid ingress and stress / load transmission, in this manner, protects the connection between the polymer layer 504 and the annular polymer extension 436.

[0080] The first seal 410 is disposed in the further recess 448 of the end-fitting 400 (as described previously, in relation to Fig. 5). The first seal 410 is annular and has a complimentary profile to the further recess 448. The further recess 448 has a tapered profile, and the first seal 410 has a tapered profile. The further recess 448 includes an elastomeric ring 406a disposed between the first seal 410 and the polymer layer 504. The elastomeric ring 406a is disposed substantially mid-way along a length of the further recess 448.

[0081] Fig. 7 illustrates the end-fitting 400 of Fig. 6 including a first collar 414.

[0082] The end-fitting 400 includes a first collar 414. The first collar 414 is configured to energise the first seal 410 disposed in the further recess 448, such that fluid ingress between the first section 444a of the body 408 and the polymer layer 504 is prevented.

[0083] The first collar 414 is disposed at the end 452 of the body 408, and adjacent to the first section 444a of the body 408. The first collar 414 includes at least one receiving portion 411 configured to receive fixings 450 configured to join the first collar 414 to the first section 444a of the body 408. As shown in Fig. 7, in this case, the receiving portion 411 is disposed at at least two points around the circumference of the first collar 414. The receiving portion 411 of the first collar 414 corresponds to the receiving portion 492a of the first section 444a, such that a fixing 450 may be received through both the receiving portion 411 of the first collar 414 and the receiving portion 492a of the first section 444a. The first collar 414 is formed of metal. In this case, the first collar 414 is formed of stainless steel. Aptly, the first collar 414 is made of carbon or alloy steel. Aptly, the first collar 414 is made of aluminium, or titanium alloy. Optionally, the first collar 414 may be at least partly coated with a suitable corrosion protection coating system, such as an epoxy-based coating.

[0084] During affixing the fixing 450 to the receiving portion 411 of the first collar 414 and the receiving portion 492a of the first section 444a, the first collar 414 moves towards the first section 444a. The first collar 414, in turn, applies a pressure to the first seal 410 disposed in the further recess 448, and energises the first seal 410 to move along the further recess 448 and swage against the first section 444a. More specifically, the first seal 410 swages against the tapered section 446 of the internal surface 447 of the first section 444a.

[0085] When the first seal 410 is swaged against the first section 444a, the first section 444a deforms the first seal 410. The first seal 410 is deformed such that the first seal 410 is compressed against the polymer layer 504. More specifically, the first seal 410 is compressed against an external surface of the polymer layer 504. At least a portion of the first seal 410 proximate to the second end 455 of the tapered section 446 is configured to deform radially inwards when the first seal 410 is urged into the recess 448, pushing into an intimate engagement with the polymer layer 504. Compressing the first seal 410 against the polymer layer 504, in this manner, prevents fluid ingress between the first seal 410 and the polymer layer 504. The first seal 410 also comprises a tapered seal surface configured to engage with an opposing sealing surface of the tapered section 446 of the first section 444a of the body 408. The elastomeric ring 406a disposed between the first seal 410 and the polymer layer 504 can further contribute to preventing fluid ingress between the first seal 410 and the polymer layer 504. The first collar 414 is further configured to prevent the first seal 410 from being removed from the first end 453 of the further recess 448.

[0086] Fig. 8 illustrates the end-fitting 400 of Fig. 7 including a second seal 404.

[0087] The end-fitting 400 includes a second seal 404. The second seal 404 is configured to be energised, in use, such that fluid ingress between the second section 418b of the sleeve 402 and the annular polymer extension 436 is prevented. Furthermore, the annular polymer layer 436 utilises hydrostatic pressure acting on the end-fitting 400 to compress against the second seal 404, further contributing to preventing fluid ingress between the second section 418b of the sleeve 402 and the annular polymer extension 436. Preventing fluid ingress, in this manner, protects the connection between the polymer layer 504 and the annular polymer extension 436.

[0088] The second seal 404 is disposed in the recess 430 (as described previously, in relation to Fig. 4). The second seal 404 is annular and has a complimentary profile to the recess 430. The second seal 404 comprises a seal surface configured to engage with an opposing sealing surface of the tapered section 424 of the recess 430. The recess 430 has a tapered profile, and the second seal 404 has a tapered profile. The recess 430 includes an elastomeric ring 406b disposed between the second seal 404 and the annular polymer extension 436. The elastomeric ring 406b is disposed substantially mid-way along a length of the recess 430.

[0089] Fig. 9 illustrates the end-fitting 400 of Fig. 8 including a second collar 412.

[0090] The end-fitting 400 includes a second collar 412. The second collar 412 is configured to energise the second seal 404 disposed in the recess 430 such that fluid ingress between the second section 418b of the sleeve 402 and the annular polymer extension 436 is prevented. The second collar 412 further allows a connection to a jacket 416 of the endfitting 400 such that further elements of the end-fitting 400 are enclosed thereunder. The second collar 412 is disposed at the further end 456 of the body 408, and adjacent to the second section 444b of the body 408. The second collar 412 is received in the receiving portion 484 of the second section 418b of the sleeve 402, and the receiving portion 492b of the second section 444b of the body 408. The second collar 412 includes at least one receiving portion 413a configured to receive fixings 454 configured to join the second collar 412 to the second section 444b of the body 408. As shown in Fig. 9, in this case, the receiving portion 413a is disposed at at least two points around the circumference of the second collar 412. The receiving portion 413a of the second collar 412 corresponds to the further receiving portion 492c of the second section 444b, such that a fixing 454 may be received through both the receiving portion 413a of the second collar 412 and the receiving portion 492c of the second section 444b. The second collar 412 is formed of metal. In this case, the second collar 412 is formed of stainless steel. Aptly, the second collar 412 is made of carbon or alloy steel. Aptly, the second collar 412 is made of aluminium, or titanium alloy. Optionally, the second collar 412 may be at least partly coated with a suitable corrosion protection coating system, such as an epoxy-based coating.

[0091] During affixing the fixing 454 to the receiving portion 413a of the second collar 412 and the further receiving portion 492c of the second section 444b, the second collar 412 moves towards both the second section 444b of the body 408 and the second section 418b of the sleeve 402. The second collar 412, in turn, applies a pressure to the second seal 404 disposed in the recess 430, and energises the second seal 404 to move along the recess 430 and swage against the second section 418b of the sleeve 402. More specifically, the second seal 404 swages against the tapered section 424 of the external surface 434 of the second section 418b. When the second seal 404 is swaged against the second section 418b, the second section 418b deforms the second seal 404. The second seal 404 is deformed such that the second seal 404 is compressed against the annular polymer extension 436. More specifically, the second seal 404 is compressed against an internal surface of the annular polymer extension 436. At least a portion of the second seal 404 proximate to the second end 426a of the tapered section 424 is configured to deform radially outwards when the second seal 404 is urged into the recess 430, pushing into an intimate engagement with the annular polymer extension 436. Compressing the second seal 404 against the annular polymer extension 436, in this manner, prevents fluid ingress between the second seal 404 and the annular polymer extension 436. The elastomeric ring 406b disposed between the second seal 404 and the annular polymer extension 436 further contributes to preventing fluid ingress between the second seal 404 and the annular polymer extension 436. The second collar 412 is further configured to prevent the second seal 404 from being removed from the second end 426b of the recess 430. External hydrostatic pressure acting on the end-fitting 400 compresses the annular polymer extension 436 against the second seal 404. Aptly, the hydrostatic pressure acts through the second section 444b of the body 408. Additionally, should the fluid seal at the first seal 410 fail, the hydrostatic pressure will act to enhance the fluid seal at the second seal 404 by acting to compress the annular polymer extension 436 against the second seal 404.

[0092] The second collar 412 includes further receiving portions 413b for receiving a fixing 460 configured to join a jacket 416 of the end-fitting 400 to the second collar 412 (as described later, in relation to Fig. 10). As shown in Fig. 9, in this case, the further receiving portion 413b is disposed at at least two points around the circumference of the second collar 412. As such, a plurality of fixings, can be used to join the second collar 412 with the jacket 416.

[0093] Fig. 10 illustrates the end-fitting 400 of Fig. 9 including a jacket 416.

[0094] The end-fitting 400 includes a jacket 416 for receiving and enclosing further elements of the flexible pipe 1000.

[0095] The jacket 416 is disposed at an end 471 of the second collar 412. The jacket 416 is disposed adjacent to the second collar 412. The jacket 416 includes a receiving portion 473 configured to receive fixings 460 configured to join the jacket 416 to the second collar 412. As shown in Fig. 10, in this case, the receiving portion 473 is disposed at two points around the circumference of the jacket 416. The receiving portion 473 of the jacket 416 corresponds to the further receiving portion 413b of the second collar 412, such that a fixing 460 may be received through both the receiving portion 473 of the jacket 416 and the receiving portion 413b of the second collar 412. The jacket 416 is formed of metal. In this case, the jacket 416 is formed of stainless steel. Aptly, the jacket 416 is made of carbon or alloy steel. Aptly, the jacket 416 is made of aluminium, or titanium alloy. Optionally, the jacket 416 may be at least partly coated with a suitable corrosion protection coating system, such as an epoxy-based coating.

[0096] Fig. 11a and 11b illustrates a further end-fitting 400 of a flexible pipe 1000 according to an embodiment of the invention, the further end-fitting 400 including a sealing assembly 480.

[0097] In this embodiment, the external surface 434 of the second section 418b of the sleeve 402 includes a stepped section 469, instead of a tapered section 424 (as described previously, in relation to Fig. 4). The stepped section 469 has a smaller diameter than any other part of the external surface 434 of the second section 418b. The stepped section 469 has a first end 475a disposed at the end of the sleeve 402, and a second end 475b disposed at a position along the length of the external surface 434 of the second section 418b. At the second end 475b of the stepped section 469, the stepped section 469 includes an end surface orientated perpendicular to a central, longitudinal axis 432 of the end-fitting 400.

[0098] The end-fitting 400 includes a recess (not shown) disposed between the second section 418b of the sleeve 402 and the annular polymer extension 436. More specifically, the recess is disposed between the stepped section 469 of the second section 418b and the annular polymer extension 436, such that the recess has a rectangular profile (as shown in Fig. 11a and 11b). The recess is annular. The recess is configured to receive a sealing assembly 480.

[0099] The end-fitting 400 includes a sealing assembly 480. The sealing assembly 480 provides an alternative seal to the second seal 404 (as described previously, in relation to Fig. 8). The sealing assembly 480 is configured to be energised, in use, such that fluid ingress between the second section 418b of the sleeve 402 and the annular polymer extension 436 is prevented. Preventing fluid ingress, in this manner, protects the connection between the polymer layer 504 and the annular polymer extension 436.

[0100] The sealing assembly 480 is disposed in the recess provided by the stepped section 469. The sealing assembly 480 is annular and has a complimentary profile to the recess. The recess may have a rectangular profile, and the sealing assembly 480 may have a complimentary rectangular profile. Other complimentary profiles for the recess and the sealing assembly 480 are possible.

[0101] As shown in Fig. 11b, the sealing assembly 480 includes a first part 438a and a second part 438b. The second part 438b is disposed radially outwardly of the external surface 434 of the second section 418b. More specifically, the second part 438b is disposed radially outwardly of the stepped section 469 of the external surface 434 of the second section 418b. The first part 438a is disposed between the second part 438b and the annular polymer extension 436. The first part 438a includes a first surface 440 and the second part 438b includes a second surface 442. The first surface 440 of the first part 438a and the second surface 442 of the second part 438b are inclined to one another.

[0102] In this embodiment, during joining the second collar 412 to the second section 444b of the body 408, the second collar 412 moves towards both the second section 444b of the body 408 and the second section 418b of the sleeve 402. The second collar 412, in turn, applies a pressure to the first part 438a disposed in the recess, and energises the first part 438a to move along the recess and swage against the second part 438b and / or the end surface of the stepped section 469. More specifically, the first surface 440 of the first part 438a swages against the second surface 442 of the second part 438b.

[0103] When the first part 438a is swaged against the second part 438b and / or the end surface of the stepped section 469, the second part 438b and / or the end surface deforms the first part 438a. The first part 438a is deformed such that the first part 438a is compressed against the annular polymer extension 436. More specifically, the first part 438a is compressed against, and forced into an intimate relationship with, an internal surface of the annular polymer extension 436. Compressing the first part 438a against the annular polymer extension 436, in this manner, prevents fluid ingress between the first part 438a and the annular polymer extension 436. The second collar 412 is further configured to prevent the sealing assembly 480 from being removed from a first end 475a of the recess.

[0104] External hydrostatic pressure acting on the end-fitting 400 compresses the annular polymer extension 436 against the first part 438a. Aptly, the hydrostatic pressure acts through the second section 444b of the body 408. The materials of the first part 438a and the second part 438b are metal. The first part 438a and the second part 438b may be the same metal, or may be different metals. For instance, the first part 438a may be a stainless steel or a nickel alloy. Whereas, the second part 438b may also be a stainless steel or a nickel alloy, or may be another metal, for instance brass, bronze, or alloy steel. Optionally, one or both the first part 438a and the second part 438b may be coated with a low friction coating system, for instance, a coating comprising PTFE, or the like.

[0105] Fig. 12a and 12b illustrates a further end-fitting 400 of a flexible pipe 1000 according to an embodiment of the invention, the further end-fitting 400 including a further sealing assembly 482.

[0106] The further end-fitting 400 includes a recess and a sealing assembly 480 as described previously, in relation to Fig. 11a and 11b.

[0107] In this embodiment, the end-fitting 400 includes a further recess (not shown) disposed at the end 452 of the body 408, and between the first collar 414 and the polymer layer 504 of the pipe body 500. The further recess may have a rectangular profile (as shown in Fig. 12a and 12b). The further recess is annular. The further recess is configured to receive a further sealing assembly 482.

[0108] The end-fitting 400 includes a further sealing assembly 482. The further sealing assembly 482 provides an alternative seal to the first seal 410 (as described previously, in relation to Fig. 6). The further sealing assembly 482 is configured to be energised, in use, such that fluid ingress between the first section 444a of the body 408 and the polymer layer 504 is prevented. Also, the portion of the polymer layer 504 inside the end fitting 400 (i.e. , that beyond the first seal 410) is isolated from forces or stress loading present in the polymer layer 504 outside of the end fitting 400, as a result of tension or bending of the pipe body 500. Preventing fluid ingress and / or stress / loading transmission, in this manner, protects the weld connection between the polymer layer 504 and the annular polymer extension 436.

[0109] The further sealing assembly 482 is disposed in the further recess. The further sealing assembly 482 is annular and has a complimentary profile to the further recess. The further recess may have a rectangular profile, and the further sealing assembly 482 may have a rectangular profile. Other complimentary profiles for the recess and the further sealing assembly 482 are possible.

[0110] As shown in Fig. 12b, the further sealing assembly 482 includes a first part 462a and a second part 462b. The second part 462b is disposed radially outwardly of the polymer layer 504. The first part 462a is disposed between the second part 462b and the first collar 414. The first part 462a includes a first surface 464 and the second part 462b includes a second surface 466. The first surface 464 of the first part 462a and the second surface 466 of the second part 462b are inclined to one another.

[0111] In this embodiment, during joining the first collar 414 to the first section 444a of the body 408, the first collar 414 moves towards the first section 444a. The first collar 414, in turn, applies a pressure to the second part 462b disposed in the further recess, and energises the second part 462b to move along the further recess and swage against the first part 462a and / or the first section 444a of the body 408. More specifically, the second surface 466 of the second part 462b swages against the first surface 464 of the first part 462a.

[0112] When the second part 462b is swaged against the first part 462a and / or the first section 444a, the first part 462a and / or the first section 444a deforms the second part 462b. The second part 462b is deformed such that the second part 462b is compressed against, and forced into an intimate relationship with, the polymer layer 504. More specifically, the second part 462b is compressed against an exterior surface of the polymer layer 504. Compressing the first part 438a against the polymer layer 504, in this manner, prevents fluid ingress between the second part 462b and the polymer layer 504. The first collar 414 is further configured to prevent the further sealing assembly 482 from being removed from an end of the further recess.

[0113] Fig. 13 illustrates a further end-fitting 400 of a flexible pipe 1000 according to an embodiment of the invention, the further end-fitting 400 including a third seal 405.

[0114] In this embodiment, the further end-fitting 400 includes a supplementary recess (not shown). The supplementary recess is configured to receive a third seal 405 of the end-fitting 400, the third seal 405 configured to prevent fluid ingress between the second section 444b of the body 408 and the annular polymer extension 436. The supplementary recess is partially disposed between both the first section 444b and the annular polymer extension 436, and the second collar 412 and the annular polymer extension 436. More specifically, the supplementary recess is partially disposed between 5 both the first section 444b and an exterior surface of the annular polymer extension 436, and the second collar 412 and the exterior surface of the annular polymer extension 436.

[0115] The supplementary recess may have a trapezoidal shape. The supplementary recess is annular.

[0116] 10 The further end-fitting 400 includes a third seal 405. The third seal 405 is configured to be energised, in use, such that fluid ingress between the second section 444b of the body 408 and the annular polymer extension 436 is prevented. Preventing fluid ingress, in this manner, protects the connection between the polymer layer 504 and the annular polymer extension 436.

[0117] 15

[0118] The third seal 405 is disposed in the supplementary recess. The third seal 405 is annular and has a complimentary profile to the supplementary recess. The supplementary recess may have a trapezoidal profile and the third seal 405 may also have a trapezoidal profile.

[0119] 20 During joining the second collar 412 to the second section 444b of the body 408, the second collar 412 moves towards the second section 444b. The second collar 412, in turn, applies a pressure to the third seal 405 disposed in the supplementary recess, and energises the third seal 405 to move along the supplementary recess and swage against the second section 444b.

[0120] 25

[0121] When the third seal 405 is swaged against the second section 444b, the second section 444b deforms the third seal 405. The third seal 405 is deformed such that the third seal 405 is compressed against the annular polymer extension 436. More specifically, the third seal 405 is compressed against, and forced into an intimate relationship with, an external surface

[0122] 30 of the annular polymer extension 436. Compressing the third seal 405 against the annular polymer extension 436, in this manner, prevents fluid ingress between the third seal 405 and the annular polymer extension 436. The second collar 412 is further configured to prevent the third seal 405 from being removed from an end of the supplementary recess. It will be noted that the second seal 404 and third seal 405, shown in Fig. 13, have complimentary, similar, but opposing profiles. The second seal 404 and third seal 405 may comprise similar or different profiles to balance, and promote, engagement and sealing with the annular polymer extension 436.

[0123] In this embodiment, as shown in Fig. 13, the annular polymer extension 436 includes a portion 489 that is inclined to a central, longitudinal axis (not shown) of the end-fitting 400. The portion 489 of the annular polymer extension 436 has a complimentary profile to an external, inclined surface of the second section 418b.

[0124] Fig. 14a illustrates a method 600 of assembling a flexible pipe 1000 according to an embodiment of the invention.

[0125] The method 600 of assembling a flexible pipe 1000 includes the step 602 of providing a sleeve 402 of an end-fitting 400. The sleeve 402 includes a first section 418a and a second section 418b. The step 602 further includes providing an annular polymer extension 436 of the end-fitting 400. The step 602 further includes partially disposing the annular polymer extension 436 radially outwardly of the first section 418a, and disposing the annular polymer extension 436 radially outwardly of the second section 418b.

[0126] The method 600 further includes the step 604 of providing a recess 430 of the end-fitting 400 and disposing the recess 430 between the second section 418b of the sleeve 402 and the annular polymer extension 436.

[0127] The method 600 further includes the step 606 of providing a pipe body 500 including a polymer layer 504. The step 606 further includes partially inserting the first section 418a of the sleeve 402 radially inwardly of the polymer layer 504.

[0128] Fig. 14b illustrates a further method 650 of assembling a flexible pipe 1000 according to an embodiment of the invention. The method 650 of assembling a flexible pipe 1000 includes the steps 602, 604, 606 of the method 600 of assembling a flexible pipe 1000. In this case, the method 650 further includes steps 608, 610, 612, 614, 616, 618, 620.

[0129] The method 650 further includes the step 608 of connecting the annular polymer extension 436 of the end-fitting 400 to the pipe body 500. The step 608 includes the process of connecting (for instance, using polymer welding) the annular polymer extension 436 to a terminal end of a polymer layer 504 of the pipe body 500 via a fluid tight fully circumferential annular connection. The annular polymer extension 436 is thereby welded to the polymer layer 504 of the pipe body 500.

[0130] The method 650 further includes the step 610 of providing a seal 404 of the end-fitting 400, and locating the seal 404 in the recess 430. The seal 404 is configured to prevent fluid ingress between the second section 418b of the sleeve 402 and the annular polymer extension 436.

[0131] The method 650 further includes the step 612 of providing a body 408 including a first section 444a and a second section 444b. The step 612 further includes partially disposing the first section 444a radially outwardly of the polymer layer 504; and disposing the second section 444b radially outwardly of the annular polymer extension 436.

[0132] The method 650 further includes the step 614 further includes providing a further recess 448 between the first section 444a of the body 408 and the polymer layer 504. The step 614 further includes disposing a further seal 410 in the further recess 448. The further seal 410 of the end-fitting 400 is configured to prevent fluid ingress between the first section 444a of the body 408 and the polymer layer 504, and / or to provide stress / load isolation to the connection between the terminal end of the polymer layer 504 and the annular polymer extension 436.

[0133] The method 650 further includes the step 616 of providing a first collar 414 of the end-fitting 400 and affixing the first collar 414 to an end of the first section 444a of the body 408. The step 616 further includes providing a second collar 412 of the end-fitting 400 and affixing the second collar 412 to an end of the second section 444b of the body 408. The method 650 further includes the step 618 of providing a jacket 416 of the end-fitting 400 and affixing the jacket 416 to the second collar 412.

[0134] The method 650 further includes the step 620 of energising the seal 404 such that the seal 404 is swaged against an external surface 434 of the second section 418b of the sleeve 402. The step 620 further includes energising the further seal 410 such that the further seal 410 is swaged against an internal surface of the first section 444a of the body 408.

[0135] Various modifications to the detailed arrangements as described above are possible.

[0136] A sealant or an adhesive may be introduced between the first section 418a of the sleeve 402 and the polymer layer 504 of the pipe body 500, such that fluid ingress between the first section 418a and the polymer layer 504 is further prevented.

[0137] The first section 418a of the sleeve 402 may include serrations on an outer surface, such that the first section 418a results in an interference fit with the polymer layer 504. The serrations may include a labyrinth profile to improve the contact stress between the elements.

[0138] Instead of the annular polymer extension 436 being formed of polyamide, the annular polymer extension 436 maybe formed of any material configured to be connectable to the polymer layer 504 of the pipe body 500. For example, the annular polymer extension 436 may have an inner metal part and an outer polymer cover, to enable a polymer-to-polymer weld between the polymer layer 504 and the annular polymer extension 436. Furthermore, the thickness of the annular polymer extension 436 may not be substantially equal to the thickness of the polymer layer 504. The annular polymer extension 436 may have any thickness such that the annular polymer extension 436 is weldable to the polymer layer 504. Instead of welding the annular polymer extension 436 to a terminal end of the polymer layer 504, the annular polymer extension 436 and the polymer layer 504 may be adhesively and / or mechanically joined.

[0139] The body 408 may include a pressure test port for testing the connection (e.g., a weld) between the annular polymer extension 436 and the polymer layer 504. The pressure test port may extend from an external surface of the body 408, through the body 408, and to an annular void of the body 408, disposed around the connection between the annular polymer extension 436 and the polymer layer 504.

[0140] Instead of affixing the first collar 414 to the first section 444a of the body 408 and / or the second collar 412 to the second section 444b of the body 408 and / or the jacket 416 to the second collar 412 using fixings (as described above), said elements may be joined to one another by any means known in the art, for example, welding, use of adhesives, or mechanical joints.

[0141] The jacket 416 may include a jacket insert. The jacket insert of the jacket 416 may be disposed radially inwardly of the jacket 416, and affix to the second collar 412 by any means known in the art.

[0142] The polymer layer 504 of the pipe body 500 may be any layer of the pipe body 500. The polymer layer 504 may include multiple layers of the pipe body 500.

[0143] The tapered portion 496 of the first section 418a of the sleeve 402 may be further configured to prevent gap formation between the first section 418a and the polymer layer 504.

[0144] The recess 430 and / or the further recess 448 and / or the supplementary recess may be any shape suitable to receive a seal, for example, triangular or any quadrilateral shape.

[0145] The first seal 410 and / or the second seal 404 and / or the third seal 405 maybe plastically deformable or elastically deformable, and may comprise a metal, a polymer, an elastomer, a composite material, or a combination of any of these.

[0146] Instead of the recess 430 and / or the further recess 448 and / or the supplementary recess being annular, the recess 430 and / or the further recess 448 and / or the supplementary recess may be disposed at at least one point around a circumference of the end-fitting 400.

[0147] The jacket 416 and the second collar 412 may be integral with one another. The precise dimensions of the features of the end-fitting 400 have been described for example only.

[0148] 5 With the above-described arrangement, the polymer layer of the pipe body is connected, for example, welded, to an annular polymer extension of the end-fitting. That is, a polymer-to- polymer weld can be used. This helps overcome the aforementioned difficulties in connecting the polymer layer to a metallic component of the end-fitting. 0 With the above-described arrangement, a body of the end-fitting is disposed radially outwardly of both the polymer layer and the annular polymer extension, and the connection (e.g., a weld) between the annular polymer extension and the polymer layer. The connection between the annular polymer extension and the polymer layer is thereby protected from failure, providing an improved connection between the end-fitting and the pipe body.

[0149] With the above-described arrangement, providing the second section of the sleeve of the endfitting enables a seal to be disposed radially inwardly of the annular polymer extension. Hydrostatic pressure acting on the end-fitting urges the annular polymer extension towards the seal, continually helping to maintain the seal between the second section of the sleeve0 and the annular polymer extension, and thereby prevent fluid ingress between the elements. Furthermore, increasing the compressive force acting on the seal, in this manner, overcomes the adverse effects of polymer creep on the seal.

[0150] It will be clear to a person skilled in the art that features described in relation to any of the5 embodiments described above can be applicable interchangeably between the different embodiments. The embodiments described above are examples to illustrate various features of the invention.

[0151] Throughout the description and claims of this specification, the words “comprise” and0 “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.

[0152] 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.

[0153] 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.

Claims

CLAIMS1. An end-fitting for joining to a pipe body, wherein the end-fitting comprises: a sleeve comprising: a first section partially insertable radially inwardly of a polymer layer of the5 pipe body; and a second section; an annular polymer extension connectable to the pipe body, the annular polymer extension partially disposed radially outwardly of the first section of the sleeve and disposed radially outwardly of the second section of the sleeve; and10 a recess disposed between the second section of the sleeve and the annular polymer extension, for receiving a seal to prevent fluid ingress between the second section of the sleeve and the annular polymer extension.

2. An end-fitting according to claim 1, wherein the end-fitting comprises the seal in the 15 recess.

3. An end-fitting according to claim 2, wherein the seal comprises a complimentary profile to the recess.20 4. An end-fitting according to claim 2 or 3, wherein the seal is energised, in use, such that the seal is swaged against an external surface of the second section of the sleeve.

5. An end-fitting according to any of claims 2 to 4, wherein an external surface of the second section of the sleeve comprises a tapered section, such that the recess comprises25 a tapered profile.

6. An end-fitting according to any of claims 2 to 5, wherein the end-fitting comprises a body comprising:a first section partially disposable radially outwardly of the polymer layer of the pipe body; and a second section disposed radially outwardly of the annular polymer extension of the end-fitting, the second section of the body having a complimentary profile to an external surface of the annular polymer extension of the end-fitting.

7. An end-fitting according to claim 6, wherein the body comprises a further recess disposed between the first section of the body and the polymer layer of the pipe body, in use, and wherein the end-fitting comprises a further seal configurable to be located in the further recess, to prevent fluid ingress between the first section of the body and the polymer layer of the pipe body.

8. An end-fitting according to claim 7, wherein the end-fitting comprises a collar affixed to an end of the first section of the body, and wherein the collar is configured to energise the further seal, in use, such that the further seal is swaged against an internal surface of the first section of the body.

9. An end-fitting according to any of claims 6 to 8, wherein the end-fitting comprises a further collar affixed to an end of the second section of the body, and wherein the further collar is configured to energise the seal, in use, such that the seal is swaged against the external surface of the second section of the sleeve.

10. An end-fitting according to any of the preceding claims, wherein the annular polymer extension of the end-fitting comprises a polyamide.

11. An end-fitting according to claim 10, wherein the annular polymer extension is configured to be connectable to the polymer layer of the pipe body.

12. A flexible pipe, wherein the flexible pipe comprises: a pipe body comprising a polymer layer; and an end-fitting comprising: a sleeve comprising: a first section partially inserted radially inwardly of the polymer layer of the pipe body; and a second section; an annular polymer extension connectable to the pipe body, the annular polymer extension partially disposed radially outwardly of the first section of the sleeve and disposed radially outwardly of the second section of the sleeve; and a recess disposed between the second section of the sleeve and the annular polymer extension, for receiving a seal to prevent fluid ingress between the second section of the sleeve and the annular polymer extension.

13. A method of assembling a flexible pipe, wherein the method comprises: providing a pipe body comprising a polymer layer; providing a sleeve of an end-fitting comprising: a first section; and a second section; providing an annular polymer extension connectable to the pipe body, the annular polymer extension partially disposed radially outwardly of the first section of the sleeve and disposed radially outwardly of the second section of the sleeve; providing a recess of the end-fitting and disposing the recess between the second section of the sleeve and the annular polymer extension; and partially inserting the first section of the sleeve radially inwardly of the polymer layer of the pipe body.

14. A method according to claim 13, wherein the method comprises providing a seal of the end-fitting and locating the seal in the recess, the seal configured to prevent fluid ingress between the second section of the sleeve and the annular polymer extension.

15. A method according to claim 14, wherein the method comprises energising the seal such that the seal is swaged against an external surface of the second section of the sleeve.

16. A method according to any of claims 13 to 15, wherein the method comprises connecting the annular polymer extension to the pipe body.

17. A method according to claim 16, wherein the method comprises connecting the annular polymer extension to the polymer layer of the pipe body.

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