Backup seal and sealing

Abstract

A seal ring element, a method of testing activation of a first seal and a further seal provided between an end fitting component for a flexible pipe and a common seal ring element at respective spaced apart locations, and a method of terminating flexible pipe body are disclosed. The seal ring element is for simultaneously providing a first seal circumferentially around an outer surface of a tubular polymer layer and a further seal with an end fitting component of an end fitting of a flexible pipe. The seal ring element comprises an annular body that has a cross section comprising a body portion, an arm portion, extending away from a side face region of the body portion, that comprises a radially inwards facing abutment surface and a radially outwards facing abutment surface, and an annular seal element at the side face region disposed radially outside the radially outwards facing abutment surface.

Description

[0001] BACKUP SEAL AND SEALING

[0002] The present invention relates to a method and apparatus for securing flexible pipe body in an end fitting. In particular, but not exclusively, the present invention relates to the use of an annular recess or protuberance on a side face of a seal ring to help provide a backup or test seal between an end fitting component for a flexible pipe (such as an end fitting body or end fitting jacket) and the seal ring.

[0003] Flexible pipes are widely used in the oil and gas industry in offshore applications for the transportation of oil, gas, water, or other fluids from one location to another. Flexible pipe is particularly useful in connecting sea-level supporting structures and subsea locations (which may be deep underwater, say 1000 metres or more), where the pipe may act as a riser. A flexible pipe is generally formed as an assembly of flexible pipe body and one or more end fittings. Flexible pipe body may 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). Due to their location, flexible pipes are exposed to a range of challenging conditions that may have high pressures, seawater, high tensile strain, and corrosive environments. Flexible pipe body is therefore composed of several concentric polymeric, metallic, and / or composite layers. For example, pipe body may include polymer and metal layers, or polymer and composite layers, or polymer, metal and composite layers. Layers may be formed from a single piece such as an extruded tube or by helically winding one or more wires at a desired pitch or by connecting together multiple discrete hoops that are arranged concentrically side-by-side. Depending upon the layers of the flexible pipe used and the type of flexible pipe some of the pipe layers may be bonded together or remain unbonded. The polymeric layers generally provide sealing from fluid ingress and the metallic layers structural rigidity.

[0004] Some flexible pipes have 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 (for example in excess of 8202 feet (2500 metres)) where environmental factors are more extreme. For example, in such deep and ultra-deep water environments, ocean floor temperature increases the risk of production fluids cooling to a temperature that may lead to pipe blockage. In practice, flexible pipes are conventionally designed to perform at operating temperatures of -30°C to +130°C and pipe body are being developed for even more extreme temperatures. Increased depths also increase the pressure associated with the environment in which the flexible pipe mustoperate. 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 pressures acting on the flexible pipe from within, for example with internal pressures ranging from zero to 140 MPa from bore fluid acting on the pipe. As a result, the need for high levels of performance and environmental resilience from certain layers such as a pipe carcass or a pressure armour or a tensile armour layer of the flexible pipe body is increased. It is noted for the sake of completeness that flexible pipe may also be used for shallow water applications (for example less than around 500 metres depth) or even for shore (overland) applications.

[0005] It is well-known that there are many varied problems associated with the provision of end fittings for ends of flexible pipe body. The end fittings must ensure both good fastening and good sealing. 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 very different material characteristics such as 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, flexible pipe body typically includes an internal barrier layer formed generally as a polymer sheath or inner pressure sheath. Such a layer operates as a primary liquid retaining layer. To prevent rupture of such a layer or indeed any underlying layer under high pressure caused by the pressure of the transported fluid, an interlocked wire layer is often located outside the barrier layer. Armour layers formed by layers of wire may also be provided to sustain tensile loads and internal pressure. If a pressure armour layer is not supported along its length, it is possible for portions of the barrier layer or other such underlying layer to burst through under pressure and cause failure of the terminating structure. All of these layers must be adequately terminated in an end fitting of some kind at the two ends of any segment of pipe body.

[0006] It is important to provide a fluid seal where any fluid containing layer is terminated in an end fitting. A continuous fluid impermeable dam must effectively be provided that blocks flow of fluid out of a central bore region of a flexible pipe. Current sealing technology may utilise seal rings that provide polymer-to-metal and metal-to-metal sealing regions. The metal-to-metal sealing region may present problems during use, in particular when the conveyed fluid is gas at high pressures. Micro-leakages may be generated at the metal-to-metal sealing region, for example due to galling caused by assembly issues, poor lubrication, misalignment, ovality, lack of concentricity or the like. Galling is a form of wear caused by adhesion between sliding surfaces, such as for two metal surfaces with similar hardness under high contact pressure.These micro-leakages may provide a leakage path that allow for the passage of contaminants (such as carbon dioxide, CO2, or hydrogen sulphide, H2S) into the annulus, creating an environment which may become more severe than the environment indicated by permeation analyses, and which may therefore cause premature flexible pipe failure.

[0007] It is an aim of the present invention to at least partly mitigate one or more of the above-mentioned problems.

[0008] It is an aim of certain embodiments of the present invention to provide an improved seal ring and end fitting configuration, to provide a higher degree of seal integrity over a longer period of time than conventional arrangements.

[0009] It is an aim of certain embodiments of the present invention to reduce the effect of galling on seal integrity over a longer period of time than conventional arrangements.

[0010] It is an aim of certain embodiments of the present invention to provide a further seal between a seal ring element and end fitting component, such as an end fitting body or end fitting jacket, to act as a backup seal in case of failure of a metal-to-metal sealing region.

[0011] It is an aim of certain embodiments of the present invention to provide a method of testing activation of a first seal and a further seal provided between an end fitting component (such as an end fitting body or end fitting jacket) for a flexible pipe and a common seal ring element at respective spaced apart locations.

[0012] It is an aim of certain embodiments of the present invention to provide a method of terminating flexible pipe body with improved sealing between an end fitting body or end fitting jacket and a respective seal ring element.

[0013] According to a first aspect of the present invention there is provided a seal ring element for simultaneously providing a first seal circumferentially around an outer surface of a tubular polymer layer and a further seal with an end fitting component of an end fitting of a flexible pipe, comprising:

[0014] an annular body that has a cross section comprising a body portion, an arm portion, extending away from a side face region of the body portion, that comprises a radially inwards facing abutment surface and a radially outwards facing abutment surface, and an annular sealelement at the side face region disposed radially outside the radially outwards facing abutment surface.

[0015] Aptly, the seal ring element further comprises:

[0016] the annular seal element comprises an annular recess in the side face region and the seal ring element further comprises a resilient seal ring member disposed at least partially in the annular recess.

[0017] Aptly, the seal ring element further comprises:

[0018] the resilient seal ring member comprises a metal annular body that has a common cross section around a whole circumference of the metal annular body and optionally the metal annular body includes a coating material that coats a whole or at least one region of the metal annular body.

[0019] Aptly, the seal ring element further comprises:

[0020] a cross-sectional width in an axial direction of the metal annular body is greater than a depth in the axial direction of the annular recess in the side face region.

[0021] Aptly, the seal ring element further comprises:

[0022] the annular seal element comprises a resilient protuberance that extends circumferentially around the body portion and away from the side face region and that is secured to or is integrally formed with the body portion.

[0023] Aptly, the seal ring element further comprises:

[0024] the resilient protuberance is arcuate in cross section and has a free end that is radially more proximate to an imaginary centre axis of the seal ring element than a root region where the protuberance starts to extend outwards at the side face region.

[0025] Aptly, the seal ring element further comprises:

[0026] the resilient protuberance provides a metal lip seal that is dipped radially inwards towards an imaginary centre axis of the seal ring element and that optionally is inclined at an angle of between 50 degrees to 70 degrees at a root portion of the lip seal proximate to the body portion, wherein the angle is with respect to an imaginary plane containing regions of said a side face region where the annular seal element and the arm portion are not located and that lie in a common plane.Aptly, the seal ring element further comprises:

[0027] in said a cross section, the body portion is rectangular and has a straight back side face disposed in a spaced apart substantially parallel relationship with regions of said a side face region where the annular seal element and the arm portion are not located and that lie in a common plane.

[0028] Aptly, the seal ring element further comprises:

[0029] in said a cross section, the body portion has a straight radially inner face portion and a straight radially outer face portion and optionally the straight radially inner face portion comprises a whole of a radially inner facing surface of the body portion and the straight radially outer face portion comprises a whole of a radially outer facing surface of the body portion.

[0030] Aptly, the seal ring element further comprises:

[0031] the radially inwards facing abutment surface is locatable against a cylindrical outer surface of a tubular polymer layer for providing a first seal therebetween; and

[0032] the radially outwards facing abutment surface is locatable against a primary annular sealing surface region at an open mouth zone of an end fitting component for providing a further seal therebetween.

[0033] Aptly, the seal ring element further comprises:

[0034] the annular seal element is a recess holding a resilient seal ring member or is a circumferentially extending resilient protuberance and the resilient seal ring member or resilient protuberance is for providing a still further seal when urged against a secondary annular sealing surface region at an open mouth zone of an end fitting component.

[0035] Aptly, the seal ring element further comprises:

[0036] the annular body is locatable in an open mouth zone of an end fitting component and is urgeable against the end fitting component to provide two axially and radially spaced apart seals therebetween, and optionally the end fitting component is an end fitting body or end fitting jacket or inner or outer collar.

[0037] According to a second aspect of the present invention there is provided a method of testing activation of a first seal and a further seal provided between an end fitting component for a flexible pipe and a common seal ring element at respective spaced apart locations, comprising:via a fluid communication passageway that extends through an end fitting component for a flexible pipe, applying a predetermined fluid test pressure between a first seal, provided by a radially outwards facing surface of an arm portion of a seal ring element and an outwardly flared annular surface at an open mouth end of the end fitting component, and a further seal provided via a resilient element disposed between the end fitting component and a body portion of the seal ring element.

[0038] Aptly, the method further comprises:

[0039] subsequent to application of the predetermined fluid test pressure, repeatedly or after a preset period of time, determining a fluid pressure associated with an end of the fluid communication passageway.

[0040] Aptly, the method further comprises:

[0041] applying the predetermined fluid test pressure subsequent to sliding the seal ring element along a cylindrical outer surface of a tubular polymer layer of flexible pipe body against an open mouth zone of the end fitting body and before or after securing an outer jacket to an end fitting body as a step during termination of a flexible pipe body, wherein optionally the end fitting component comprises the end fitting body or the outer jacket.

[0042] According to a third aspect of the present invention there is provided a method of terminating flexible pipe body, comprising:

[0043] providing an end of at least a tubular polymer layer of a segment of flexible pipe body in an open mouth zone of an end fitting component of a flexible pipe end fitting;

[0044] urging a seal ring element previously disposed over the tubular polymer layer against the end fitting component;

[0045] providing a first seal between the end fitting component and the seal ring element via a radially outwards facing abutment surface of the seal ring element; and

[0046] providing a further seal between the end fitting component and the seal ring element via an annular seal element at a side face region of the seal ring element that is disposed radially outside the radially outwards facing abutment surface.

[0047] Aptly, the method further comprises:

[0048] providing the further seal and the first seal simultaneously as the seal ring element is urged against the end fitting component.

[0049] Aptly, the method further comprises:providing the first seal by urging a radially outwards facing abutment surface of an arm portion of an annular body of the seal ring element against an outwardly flared annular surface at an open mouth zone of the end fitting component.

[0050] Aptly, the method further comprises:

[0051] providing the further seal by urging a resilient seal ring member, that is at least partially disposed in an annular recess, in the side face region, that provides the annular seal element, against a surface of the end fitting component; and

[0052] deforming the resilient seal ring member against the end fitting component thereby activating the further seal, wherein optionally the end fitting component is an end fitting body or end fitting jacket or end fitting inner or outer collar.

[0053] Aptly, the method further comprises:

[0054] providing the further seal by urging a resilient protuberance, that extends circumferentially around a body portion of the seal ring element and away from a side face region of the seal ring element, against a surface of the end fitting component; and deforming the resilient protuberance against the end fitting component thereby activating the further seal, wherein optionally the end fitting component is an end fitting body or end fitting jacket or end fitting inner or outer collar.

[0055] Certain embodiments of the present invention provide a seal ring with an annular seal element (such as a recess or protuberance) that helps provide a backup seal to a conventional metal-to-metal sealing region between the seal ring and an end fitting component (such as an end fitting body or end fitting jacket).

[0056] Certain embodiments of the present invention provide a seal ring with an annular seal element, where the annular seal element may be a circumferentially extending recess holding a resilient seal or may be a circumferentially extending resilient protuberance. Aptly, the resilient seal may be a resilient metal seal.

[0057] Certain embodiments of the present invention provide a backup seal to a metal-to-metal sealing region by the deformation of a resilient metal seal or resilient protuberance against an end fitting component, such as an end fitting body or end fitting jacket.

[0058] Certain embodiments of the present invention help to address a potential leakage path at a metal-to-metal sealing region by providing a lodging or recess at a seal ring for the use of aresilient metal seal which acts as a backup in case of failure of the metal-to-metal sealing region of the seal ring.

[0059] Certain embodiments of the present invention utilise a resilient metal seal as a backup seal, that may be compressed in a cavity to a given portion of its original free height. The force generated through compression of the resilient metal seal produces a high contact stress at the seal / cavity interface. Sealing may therefore be provided between the seal ring and the end fitting component without experiencing sliding contact between the backup seal and cavity sealing surfaces, as may be the case at metal-to-metal sealing surfaces between the seal ring and the opposing end fitting component when the seal ring is energized and partly swaged into intimate contact with the pipe body polymer sheath to also exact sealing between the seal ring and the polymer sheath. This force is supplemented by the pressure-energization force which rises in proportion to the increase in differential pressure. That is to say, a resilient metal seal may be enhanced or further activated by the application of pressure to one side of the resilient metal seal.

[0060] Certain embodiments of the present invention provide a seal ring and / or end fitting component (such as an end fitting body, or end fitting jacket, or end fitting inner or outer collar) with geometries modified to incorporate an appropriate groove(s) or sealing recess(es) where a resilient metal seal is installed to form a backup seal. The design may make no impact to the conventional seal, respecting the existing design methodology. The only modification would be the groove(s) which may be designed to provide the required compression to the resilient metal seal. Alternatively, a groove may be formed in only the end fitting component (e.g. end fitting body or end fitting jacket) with a metal lip seal secured to or integrally formed with a body portion of the seal ring.

[0061] Certain embodiments of the present invention provide a method of terminating flexible pipe body which provides two spaced apart seals between a seal ring and an end fitting component such as an end fitting body or end fitting jacket. The seal ring also provides a seal between itself and a polymer layer such as a liner, barrier layer or outer sheath of flexible pipe body. Providing two seals between an end fitting component and a seal ring builds in redundancy for if one seal fails in the future.

[0062] Certain embodiments of the present invention provide a backup seal using a resilient metal seal. The use of resilient metal seals presents advantages such as being applicable to pressures more than 2000bar, resistant to chlorides, corrosion, and other aggressiveinfluences, and no or little ageing. Resilient metal seals may therefore represent a superior choice when compared to conventional polymeric o rings. Aptly, the resilient metal seal may include a coating material that flows under pressure to close any microscopically small irregularities in the sealing surface and improve the sealing properties.

[0063] Certain embodiments of the present invention provide a test port which enables the testing of a metal-to-metal sealing region by applying pressure between this metal-to-metal sealing region and a backup seal (e.g. resilient metallic seal). This provides an improvement relative to a prior art technique in which the test of an internal seal ring is only carried out during factory assembled testing after both end fittings are fully assembled.

[0064] Certain embodiments of the present invention provide a method of testing effective activation of two spaced apart seals provided between an end fitting component and a common seal ring. Activation in this sense means that when two parts are brought together a sealing zone that is annular or circumferentially extending around a bore region is created that prevents fluid flow across an interface region between the parts. Aptly testing can be carried out part way through termination without an end fitting jacket being introduced and tensile armour wires being entombed in a chamber between the jacket and end fitting body. In this way if a fault / failure in a seal is detected remedial action can take promptly. Alternatively testing can be made possible subsequent to completion of a termination process. This enables testing of activation of seals against an end fitting jacket at completion of termination and / or enables further monitoring to be carried out immediately prior to putting a flexible pipe in use.

[0065] Embodiments of the present invention will now be described hereinafter, by way of example only, with reference to the accompanying drawings in which:

[0066] Figure 1 illustrates a flexible pipe body;

[0067] Figure 2 illustrates certain uses of a flexible pipe;

[0068] Figure 3 illustrates a schematic view of how at least one layer of a flexible pipe body can be sealed in an end fitting;

[0069] Figure 4 illustrates a cross-sectional view of an end region of a flexible pipe body terminated in an end fitting;Figure 5a illustrates how a sealed polymer layer can be sealed in the end fitting of Figure 4 in more detail;

[0070] Figure 5b illustrates how an outer collar of an end fitting can be secured to an outer jacket of the end fitting;

[0071] Figure 6a illustrates an end-on view of a seal ring;

[0072] Figure 6b illustrates a cross-sectional view of the seal ring of Figure 6a;

[0073] Figure 7a illustrates an end-on view of a resilient metal seal;

[0074] Figure 7b illustrates a cross-sectional view of the resilient metal seal of Figure 7a;

[0075] Figure 8 illustrates a schematic view of how at least one layer of a flexible pipe body can be sealed in an end fitting;

[0076] Figure 9a illustrates an end-on view of a seal ring;

[0077] Figure 9b illustrates a cross-sectional view of the seal ring of Figure 9a;

[0078] Figure 10 illustrates a schematic view of how the activation of certain seals in an end fitting can be tested;

[0079] Figure 11 illustrates a cross-sectional view of an end region of a flexible pipe body terminated in an end fitting; and

[0080] Figure 12 illustrates a flow-diagram showing a method of terminating flexible pipe body.

[0081] In the drawings like reference numerals refer to like parts.

[0082] Throughout this description, reference will be made to a flexible pipe. It is to be appreciated that certain embodiments of the present invention are applicable to use with a wide variety of flexible pipe. For example, certain embodiments of the present invention can be used with respect to flexible pipe body and associated end fittings of the type which is manufacturedaccording to API 17J. Such flexible pipe is often referred to as unbonded flexible pipe. Other embodiments are associated with other types of flexible pipe.

[0083] It will be understood that the illustrated flexible pipes are an assembly of a portion of flexible pipe body and one or more end fittings in each of which a respective end of the pipe body is terminated. Figure 1 illustrates how pipe body 100 is formed from a combination of layered materials that form a pressure-containing conduit. Although a number of particular layers are illustrated in Figure 1, it is to be understood that certain embodiments of the present invention are broadly applicable to coaxial pipe body structures including two or more layers manufactured from a variety of possible materials. The pipe body may include one or more layers comprising composite materials, forming a tubular composite layer. 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.

[0084] A tubular composite layer is thus a layer having a generally tubular shape formed of composite material. Alternatively, a tubular composite layer is a layer having a generally tubular shape formed from multiple components one or more of which is formed of a composite material. The layer or any element of the composite layer may be manufactured via an extrusion, pultrusion or deposition process, or by a winding process in which adjacent windings of tape which themselves have a composite structure are consolidated together with adjacent windings. The composite material, regardless of manufacturing technique used, may optionally include a matrix or body of material having a first characteristic in which further elements having different physical characteristics are embedded. That is to say elongate fibres which are aligned to some extent or smaller fibres randomly orientated can be set into a main body or spheres or other regular or irregular shaped particles can be embedded in a matrix material, or a combination of more than one of the above. Aptly the matrix material is a thermoplastic material, aptly the thermoplastic material is polyethylene or polypropylene or nylon or PVC or PVDF or PFA or PEEK or PTFE or alloys of such materials with reinforcing fibres manufactured from one or more of glass, ceramic, basalt, carbon, carbon nanotubes, polyester, nylon, aramid, steel, nickel alloy, titanium alloy, aluminium alloy or the like or fillers manufactured from glass, ceramic, carbon, metals, buckminsterfullerenes, metal silicates, carbides, carbonates, oxides or the like.

[0085] The pipe body 100 illustrated in Figure 1 includes an inner pressure sheath 110 which acts as a fluid retaining layer. Optionally the inner pressure sheath is an internal pressure sheath.The inner pressure sheath of Figure 1 comprises a polymeric material. Optionally the inner pressure sheath may comprise any other suitable material. It will be appreciated that the inner pressure sheath ensures internal fluid integrity. The inner pressure sheath of Figure 1 is a polymer layer, however the internal pressure sheath may optionally be any other suitable layer. It will be appreciated that a tubular polymer layer is thus a layer having a generally tubular shape formed of a polymeric material or formed from multiple components one or more of which is formed of a polymeric material. The layer provides a boundary for any conveyed fluid. It is to be understood that this layer may itself comprise a number of sub-layers. It will be appreciated that when a carcass layer 120 is utilised the inner 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 inner pressure sheath may be referred to as a liner. A barrier layer 110 is illustrated in Figure 1.

[0086] It is noted that a carcass layer 120 is a pressure resistant layer that provides an interlocked construction that can be used as the innermost layer to prevent, totally or partially, collapse of the inner pressure sheath 110 due to pipe decompression, external pressure, and tensile armour pressure and mechanical crushing loads. The carcass is a crush resistant layer. It will be appreciated that certain embodiments of the present invention are thus applicable to ‘rough bore’ applications (with a carcass). Aptly the carcass layer is a metallic layer. Aptly the carcass layer is formed from stainless steel, corrosion resistant nickel alloy or the like. Aptly the carcass layer is formed from a composite, polymer, or other material, or a combination of materials and components. The carcass layer is usually radially positioned within the barrier layer.

[0087] The carcass layer is a “layer” in the sense that a radially innermost and outermost surface are created in single pass at a single manufacturing node. The single manufacturing node may include multiple tape handling sections axially close together so that they are effectively a single node. The node aptly extends over an axial distance of less than 2.5m. Aptly the node has a length of 1m or less.

[0088] The pipe body of Figure 1 further includes a permeation retarding layer 122 that is disposed radially outside of the inner pressure sheath 110. The permeation retarding layer 122, or low permeation layer, of Figure 1 is a layer of helically wound tape with windings that overlap with adjacent windings of the tape. It will be understood that the permeation retarding layer is made from a material that is substantially resistant to the permeation of gasses that can pass through the inner pressure sheath 110 during use of the pipe body, such as carbon dioxideand / or hydrogen sulphide for example. It will be appreciated how the permeation retarding layer may be made from a suitable material that is substantially resistant to permeation of such gasses, for example a polymeric material and / or a metallic material and / or a composite material or the like. The permeation retarding layer 122 could instead of course be a nonwound layer, for example an extruded polymeric layer or the like.

[0089] Disposed radially outside of the permeation retarding layer 122 is a further polymer layer 124. The polymer layer 124 is a sealed layer and thus is a further sealed fluid retaining layer. The polymer layer is sealed at respective sealing points in respective end fittings. It will be appreciated how the polymer layer and the inner pressure sheath 110 provide an inner annulus region of the flexible pipe body. That is to say that an inner annulus region is provided between the radially outer surface of the inner pressure sheath 110 and a radially inner surface of the polymer layer. The permeation retarding layer 122 is located in the inner annulus region. The polymer layer of Figure 1 is an extruded layer however it will be appreciated that any other suitable fluid retaining polymer layer could instead be utilised. It will be appreciated that according to certain embodiments, flexible pipe body may have no permeation retarding layer 122 and no further polymer layer 124.

[0090] The pipe body includes a pressure armour layer 130 that is a pressure resistant layer that provides 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 inner pressure sheath. Aptly as illustrated in Figure 1 the pressure armour layer is formed as a tubular layer. Aptly for unbonded type flexible pipe the pressure armour layer consists of an interlocked construction of wires with a lay angle close to 90°. Aptly in this case the pressure armour layer is a metallic layer. Aptly the pressure armour layer is formed from carbon steel, aluminium alloy, stainless steel or the like. Aptly the pressure armour layer is formed from a pultruded composite interlocking layer. Aptly the pressure armour layer is formed from a composite formed by extrusion or pultrusion or deposition. A pressure armour layer is positioned radially outside an underlying barrier layer.

[0091] The flexible pipe body illustrated also includes a first tensile armour layer 140 and second tensile armour layer 150. Each tensile armour layer is used to sustain tensile loads and optionally also internal pressure. Aptly for some flexible pipes the tensile armour windings are metal (for example steel, stainless steel or titanium or the like). For some composite flexible pipes the tensile armour windings may be polymer composite tape windings (for example provided with either thermoplastic, for instance nylon, matrix composite or thermoset, forinstance epoxy, matrix composite). For unbonded flexible pipe the tensile armour layer is 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°. Aptly the tensile armour layers are counter-wound in pairs. Aptly the tensile armour layers are metallic layers. Aptly the tensile armour layers are formed from carbon steel, stainless steel, titanium alloy, aluminium alloy or the like. Aptly the tensile armour layers have a microstructure that consists of orientated lamellae. Aptly the tensile armour layers are formed from a composite, polymer, or other material, or a combination of materials.

[0092] Aptly the flexible pipe body includes optional layers of tape 160 which help contain underlying layers and to some extent prevent abrasion between adjacent layers. A tape layer may optionally be a polymer or composite or metal or a combination of materials, also optionally comprising a tubular composite layer. Tape layers can be used to help prevent metal-to-metal contact to help prevent wear. Tape layers over tensile armours can also help prevent “birdcaging” of the tensile armour wires.

[0093] The flexible pipe body shown in Figure 1 also includes optional layers of insulation 165 and an outer sheath 170, which comprises a polymeric material. Optionally the outer sheath is a polymer layer. Optionally the outer sheath is made from any other suitable material. It will be understood that the outer sheath helps protect the pipe against penetration of seawater and other external environments, corrosion, abrasion and mechanical damage. Any thermal insulation layer helps limit heat loss through the pipe wall to the surrounding environment. It will be appreciated that insulation layers may be arranged radially outside of the outer sheath. Such insulation layer external to the outer sheath can also add protection to outer sheath. It will be appreciated that the outer sheath is a sealed fluid retaining layer that optionally is an outermost sealed (or fluid tight) layer. An annulus is a region associated with the space between fluid retaining layers of the pipe. For example, an annulus region is located between the inner pressure sheath 110 and the outer sheath 170 if the inner pressure sheath and the outer sheath are the only two fluid retaining layers. However, as is the case of the pipe of Figure 1 , a pipe can include multiple annulus regions between fluid retaining layers when more than two fluid retaining layers are included in a flexible pipe. In the pipe of Figure 1, a first (or inner) annulus is located between the inner pressure sheath and the further (or intermediate) fluid retaining polymer layer. A further (or outer) annulus is located between the further or intermediate fluid retaining layer (the polymer layer) and the outer sheath. In other words, in the flexible pipe body illustrated in Figure 1, the pressure armour layer 130, the first tensile armour layer 140, the further tensile armour layer 150, the optional layers of tape 160, and theoptional layers of insulation 165 are located in the further or outer annulus region. It will be appreciated that in some embodiments, the annulus region may contain any or none of the layers present in the flexible pipe body illustrated in Figure 1.

[0094] Each flexible pipe comprises at least one portion, referred to as a segment or section, of pipe body 100 together with an end fitting located at least one end of the flexible pipe. A respective end fitting may be used to terminate each end of the flexible pipe body. 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 Figure 1 are terminated in the end fitting in such a way as to transfer the load between the flexible pipe and the connector.

[0095] The innermost layers of flexible pipe body thus include the inner sheath which can be an extruded non-porous polymer layer that confines a bore fluid to its internal circumference, and often a carcass, a spirally wound interlocking metal structure which forms the very innermost layer. The carcass prevents the collapse of the inner sheath and also protects the inner sheath from abrasive particles. When a carcass layer is present in the flexible pipe body, the inner sheath is referred to as a barrier layer. When a carcass layer is not present in the flexible pipe body, the inner sheath is referred to as a liner.

[0096] The outermost sealed or fluid tight layer of the flexible pipe body is the outer sheath, an extruded non-porous polymer layer that protects the pipe’s structural elements from the environment around the flexible pipe and prevents the ingress of seawater. A flexible pipe body can however include additional layers located radially outside of the other sheath. These additional layers can for example include insulation layers and / or an outermost protective layer that often helps protect the outer sheath (and any insulation layers) from abrasion related damage due to contact with rough or sharp substances in the environment. The layers that are disposed radially outside of the outer sheath are typically not sealed (or fluid tight) in order to reduce the axial compression experienced by a flexible pipe in use.

[0097] The flexible pipe body illustrated includes an outer and an inner polymer layer. An annulus of such a flexible pipe is a region between the innermost fluid containing layer and the outermost fluid containing layer. The innermost layer in the annulus region is the pressure armour layer, which is made of helically wound flattened metallic wires arranged at a lay angle close to 90°. Neighbouring wound wires in the pressure armour layer interlock to control the gap between windings. Pressure armour is designed to withstand hoop stress in the pipe wall, which is caused by the bore fluid pressure. Pairs of tensile armour layers are also located in theannulus, and these may be cross-wound radially outside the pressure armour layer. Tensile armour layers may be made of slightly flattened rectangular metallic wires arranged at a lay angle of about 25 - 55°. Tensile armour layers support the weight of all internal pipe layers and transfer the resulting tensile stress to the sea-level supporting structures. The annulus may also have other layers such as anti-wear and anti-birdcaging tapes, and thermally insulating layers.

[0098] In an end fitting, flexible pipe body is terminated by sealing and securing ends of some polymer or composite layers and securing any pressure armour windings and securing the tensile armour wires. The annulus which extends along the flexible pipe body segment thus extends into a region within the end fitting. In configurations where two flexible pipes are joined end-to-end to form a pipeline there is typically no fluid connection between the annulus in one flexible pipe and the annulus in the other flexible pipe.

[0099] The flexible pipe may be utilised to transport production fluids, such as oil and / or gas and / or water, from one location to another. The flexible pipe is particularly useful in connecting a subsea location to a sea level location. Flexible pipe is generally formed as an assembly of a portion of flexible pipe body and one or more end fittings. The pipe body may be formed as a composite 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 lifetime. The pipe body illustrated is built up as a composite structure including metallic and polymer layers.

[0100] The end fittings of a flexible pipe may be used for connecting segments of flexible pipe 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 flowline 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 typically includes at least one (for example two) end fitting(s).

[0101] Figure 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 221 to a floating facility 222. For example, in Figure 2 the sub-sea location 221 includes a sub-sea flow line 225. The sub-sea flow line 225 comprises a flexible pipe, wholly or in part, resting on the sea floor 230 or buried below the sea floor and used in a static application. The floating facility 222 may be provided by aplatform and / or buoy or, as illustrated in Figure 2, a ship. The riser assembly 200 is provided as a flexible riser, that is to say a flexible pipe 240 connecting the ship to the sea floor installation. The flexible pipe may be in segments of flexible pipe body with connecting end fittings.

[0102] It will be appreciated that there are different types of riser, as is well-known by those skilled in the art. Certain embodiments of the present invention may be used with any type of riser, such as a freely suspended (free-hanging, catenary riser), a riser restrained to some extent (buoys, chains), totally restrained riser or enclosed in a tube (I or J tubes). Some, though not all, examples of such configurations can be found in API 17J. Figure 2 also illustrates how portions of flexible pipe can be utilised as a jumper 250.

[0103] Figure 3 illustrates a schematic representation of how at least one polymer layer of flexible pipe body can be sealed in an end fitting. Figure 3 illustrates a schematic view of an end region 304 of a segment of flexible pipe body 302, as further illustrated in Figure 4. It will be appreciated that the segment of flexible pipe body 302 shown in Figure 3 is a portion of the flexible pipe body 100 described with respect to Figure 1 and may be connected between two end fittings 312 (one shown) at respective terminal end regions of the segment of flexible pipe body 302. An inner pressure sheath 315 is shown in Figure 3, with an outer surface 320. It will be appreciated that the outer surface 320 of the inner pressure sheath 315 is a cylindrical outer surface. The inner pressure sheath 315 is an example of a tubular polymer layer, and it will be appreciated that according to other embodiments the inner pressure sheath 315 may alternatively be a different tubular polymer layer of the segment of flexible pipe body 100, such as the outer sheath 170. A metallic sleeve 325 is located radially within the inner pressure sheath 315. It will be appreciated that in rough bore operation the metallic sleeve 325 may be the carcass layer 120 of Figure 1 with the inner pressure sheath 315 referred to as a barrier layer in this case.

[0104] Figure 3 shows only a single end fitting 312 located at an end region 304 of the segment of flexible pipe body 302. It will be understood that the remaining end region (not shown) of the segment of flexible pipe body 302 may also be terminated in an end fitting. The end fitting 312 is a metallic structure (including an end fitting body 330) in which various layers of a segment of flexible pipe body 302 can be terminated. Figure 3 schematically shows how the inner pressure sheath 315 of the flexible pipe body 302 is sealed in the end fitting 314 via a seal ring 340. The seal ring 340 is an example of a seal ring element. It will be appreciated thatany tubular polymer layer within the segment of flexible pipe body 100 may be individually sealed by a respective seal ring as described with reference to Figure 4.

[0105] It will be appreciated that, while Figure 3 shows a schematic view in cross section, the seal ring 340 is an annular body (shown in Figures 6a and 6b). That is to say, the seal ring 340 is ring shaped and located circumferentially around the outer surface 320 of the inner pressure sheath 315 and thus also circumferentially around a bore region of the flexible pipe body and end fitting body. In the cross section shown in Figure 3, the seal ring 340 has a body portion 345 and an arm portion 350, where the arm portion 350 extends away from a side face region 355 of the body portion 345. That is to say, the arm portion 350 is an arm-shaped extension of the seal ring 340, i.e. projects from the side face region 355 of the body portion 345. The arm portion 350 has a radially inwards facing abutment surface 360, which is a surface of the arm portion 350 that faces radially inwards towards an imaginary centre axis of the seal ring 340. The radially inwards facing abutment surface 360 is locatable against the cylindrical outer surface 320 of the inner pressure sheath 315, as illustrated in Figure 3. The abutment of the radially inwards facing abutment surface 360 against the cylindrical outer surface 320 of the inner pressure sheath 315 provides a first seal at a polymer sealing region 365, adjacent a cavity region 367, which may be filled with a deformable material to prevent the inner pressure sheath 315 intruding into the cavity region 367 while promoting the controlled deformation of the arm portion 350 of the seal ring 340 during energising of the seal ring 340. It will be appreciated that the first seal is provided circumferentially around the outer surface 320 of the inner pressure sheath 315 and between the cylindrical outer surface 320 of the inner pressure sheath 315 and the radially inwards facing abutment surface 360. The polymer sealing region 365 is therefore a polymer-to-metal sealing region.

[0106] The arm portion 350 also has a radially outwards facing abutment surface 370, which is a surface of the arm portion 350 that faces radially outwards away from an imaginary centre axis of the seal ring 340. The radially outwards facing abutment surface 370 is locatable against a radially inwards facing primary annular sealing surface region 372 at an open mouth zone 375 of the end fitting body 330. The end fitting body 330 is an example of an end fitting component. It will be appreciated that while a portion of the open mouth zone 375 of the end fitting body 330 is shown as filled by the arm portion 350 of the seal ring 340 in Figure 3, when the seal ring 340 is absent the open mouth zone 375 is empty (i.e. unfilled space) and suitable for receiving the arm portion 350 of the seal ring 340. The abutment of the radially outwards facing abutment surface 370 against the primary annular sealing surface region 372 provides a further seal at the primary annular sealing region 380. It will be appreciated that the furtherseal is with the end fitting body 330 and between the primary annular sealing surface region 372 and the radially outwards facing abutment surface 370. The primary annular sealing region 380 is therefore a metal-to-metal sealing region.

[0107] In use, the seal ring 340 simultaneously provides a first seal circumferentially around the outer surface 320 of the inner pressure sheath 315 and a further seal with the end fitting body 330 of the end fitting 312 of the flexible pipe. It will be appreciated that in use the seal ring 340 may be energised to sealingly engage with the inner pressure sheath 315 and end fitting body 330. Energising of the seal ring 340 may include urging the arm portion 350 (an example of a deformable portion) of the seal ring 340 radially inwardly and into biting engagement with the outer surface 320 of the inner pressure sheath 315, as described further with reference to Figure 5. Aptly the process of energising the seal ring 340 may require the drawing of the end fitting component over the seal ring, thereby maintaining axial co-location of the seal ring 340 and the polymer sealing region 365 of the inner polymer sheath 315, while only the end fitting body 330 moves axially with respect to the end segment of pipe body 302 and the seal ring 340.

[0108] The seal ring 340 also includes an annular recess 385 (an example of an annular seal element) in the side face region 355 disposed radially outside the radially outwards facing abutment surface 370. That is to say, the annular recess 385 is annular (i.e. formed around the ringshaped seal ring 340 as illustrated in Figure 6) and located further from an imaginary centre axis of the seal ring 340 than the radially outwards facing abutment surface 370 of the arm portion 350. While in Figure 3, the annular seal element is an annular recess 385, according to other embodiments the annular seal element located at the side face region 355 may have other forms, such as a metal lip seal (example of a resilient protuberance) as described with reference to Figure 8 and 9. The seal ring 340 of Figure 3 also includes a resilient metal seal 390 (an example of a resilient seal ring member) disposed at least partially in the annular recess 385. In this case, there is a secondary annular recess located in the end fitting body 330 and the resilient metal seal 390 is disposed partially in the annular recess 385 of the seal ring 340 and partially in the secondary annular recess of the end fitting body 330. It will be appreciated that according to other embodiments, there may be no secondary annular recess in the end fitting body 330 and the resilient metal seal 390 may be disposed fully in the annular recess 385 of the seal ring 340.

[0109] It will be appreciated that, in the cross section of the annular body of the seal ring 340 in Figure 3, the body portion 345 is rectangular and has a straight back side face 397 disposed in aspaced apart substantially parallel relationship with regions of the side face region 355 where the annular recess 385 (as an example of the annular seal element) and the arm portion 350 are not located and that lie in a common plane. That is to say, in the cross section of the seal ring 340, the straight back side face 397 of the body portion 345 is spaced apart from and substantially parallel to those regions of the side face region 355 that lie in a common plane and lack the annular recess 385 and the arm portion 350. In addition, in the cross section of the annular body of the seal ring 340, the body portion 345 has a straight radially inner face portion 398 and a straight radially outer face portion 399. According to certain embodiments, the straight radially inner face portion 398 includes a whole of a radially inner facing surface of the body portion 345 and the straight radially outer face portion 399 includes a whole of a radially outer facing surface of the body portion 345.

[0110] In this case, the resilient metal seal 390 is a metal annular body that has a common cross section around a whole circumference of the metal annular body. That is to say, the resilient metal seal 390 is formed from a metal and is ring-shaped, or substantially ring-shaped, with a consistent cross-section throughout the whole circumference of the metal annular body. In Figure 3, the common cross section of the metal annular body is C shaped (or ‘horse-shoe’ shaped) but according to other embodiments the resilient metal seal 390 may have a different common cross section, such as O shaped, II shaped, V shaped, Y shaped, W shaped, or the like. It will be appreciated by those skilled in the art that the metal annular body of the resilient metal seal 390 may be a resilient metal seal, formed of various stainless steels and / or nickel alloys, such as one of the following materials: SS304, SS321, Inconel 600, Inconel X-750, Inconel 718. It may also be possible to subject the metal annular body to different heat treatments, for example, work or age hardened heat treatments, which may positively influence the performance as well as the lifetime of the resilient metal seal 390. Examples of commercial seals which may be put to use as the resilient metal seal 390 are those which can be purchased from Technetics Group (https : / / tech netics . com / technetics- prod ucts / m etal-

[0111] The resilient metal seal 390 has a cross-sectional width in an axial direction of the metal annular body greater than a depth in the axial direction of the annular recess 385 in the side face region 355 of the seal ring 340. That is to say, in an uncompressed state (e.g. prior to use), the resilient metal seal 390 is wider than the annular recess 385. Additionally, in some embodiments, in the uncompressed state, the resilient metal seal 390 may have a cross-sectional width in an axial direction of the metal annular body greater than a combined depth in the axial direction of the annular recess 385 in the side face region 355 and the secondaryannular recess in the end fitting body 330. That is to say, the resilient metal seal 390 may be wider than the total depth of recess (made up of the annular recess 385 in the seal ring 340 and the secondary annular recess in the end fitting body 330).

[0112] In use, the resilient metal seal 390 may be located at least partially in the annular recess 385 of the seal ring 340 prior to energising of the seal ring 340. Upon energising of the seal ring 340, the resilient metal seal 390 is urged against a secondary annular sealing surface region 395 at the open mouth zone 375 of the end fitting body 330. Urging of the resilient metal seal 390 against the secondary annular sealing surface region 395 compresses the metal annular body to a reduced cross-sectional width in the axial direction. For example, the reduced cross-sectional width may be about 20% of cross-sectional width in the uncompressed state. That is to say, in a compressed state the metal annular body has a reduced cross-sectional width in the axial direction than the cross-sectional width in the uncompressed state, and the metal annular body is deformed both plastically and elastically. It will be appreciated that the reduced cross-sectional width in the compressed state may be around the total depth of recess (made up of the annular recess 385 in the seal ring 340 and the secondary annular recess in the end fitting body 330). The person skilled in the art will appreciate that the force generated through compression of the resilient metal seal 390 produces a high contact stress at the interface. The high contact stress produced by compression of the resilient metal seal 390 upon urging of the resilient metal seal 390 against the secondary annular sealing surface region 395 provides a still further seal. As for the further seal described above, the still further seal is with the end fitting body 330. The still further seal is located radially outside the further seal and axially separated. That is to say, locating the annular body of the seal ring 340 in the open mouth zone 375 of the end fitting body 330 and urging the seal ring 340 (including the resilient metal seal 390 disposed in the annular recess 385) against the end fitting body 330 provides two axially and radially spaced apart seals between the end fitting body 330 and the seal ring 340. It will be appreciated that the still further seal provided by compression of the resilient metal seal 390 provides a back-up seal to the metal-to-metal sealing region of the further seal. If the metal-to-metal sealing region of the further seal fails (e.g. due to galling as described above), then the still further seal may provide a back-up seal that prevents leakage along the interface between the end fitting body 330 and the seal ring 340.

[0113] It will be appreciated that the resilient metal seal 390 may provide an enhanced still further seal upon failure of the further seal. Failure of the further seal may lead to a build-up of pressure on one side of the resilient metal seal 390, i.e. on the radially inner side, and hence an increase in differential pressure. The shape and configuration of the common cross sectionof the resilient metal seal 390 (the C shape in Figure 3) means that the increase of differential pressure upon failure of the further seal further deforms the resilient metal seal 390 by flaring out the sides of the resilient metal seal 390 to increase the pressure-energization force and provide an enhanced seal. That is to say, the seal provided by the resilient metal seal 390 may be enhanced or further activated upon an initial leakage generated by failure of the metal-to-metal sealing region of the further seal. It will additionally be appreciated that the resilient metal seal 390 may spring back in a defined manner when relieved of load (known as springback). This ensures that the tightness of the seal is maintained if lift-off of the seal ring 340 occurs and may maintain sealing performance. The resilient metal seal 390 may also be spring energised, where an internal spring reinforcement provides a further improvement to the sealing effect and improved springback.

[0114] The sealing performance of the resilient metal seal 390 may be further enhanced by use of a coating material on the metal annular body that coats a whole, or at least one region, of the metal annular body. By way of example only, the coating material may be tin, polytetrafluoroethylene (PTFE), silver, copper, gold, nickel, titanium, or the like. The thickness of the coating material may be in the range 0.01-0.07 mm or one of the sub-ranges 0.01-0.03 mm, 0.03-0.05 mm, 0.05-0.07 mm or the like. It will be appreciated that when the resilient metal seal 390 is compressed in use, the coating flows into the microscopic unevenness of the sealing surface and further seals it to improve the sealing performance. Additionally, a coating material such as PTFE or gold may also be used as protection to improve the resistance against aggressive media, e.g. corrosion or the like.

[0115] Figure 4 illustrates a cross-sectional view of a segment of flexible pipe body 100 that is terminated in an end fitting 312. The end fitting 312 shown in Figure 4 may be usable to terminate flexible pipe body that has a diameter of around 6 inches or the like. Alternative arrangements or configurations of end fitting may be used according to certain other embodiments. It will be appreciated that end fittings (such as the end fitting 312) can be connected in a back-to-back arrangement. The end fitting 312 terminates an end of a segment of flexible pipe body 100. It will be appreciated that a further end fitting can be utilised to terminate a respective end of a further segment of flexible pipe body. It will be also understood that a still further end fitting may terminate a remaining end of the segment of flexible pipe body 100 illustrated in Figure 4. The end fitting 312 can be connected to a further end fitting via respective flanges 404. These can be bolted together via bolts (not shown in Figure 4) and can include matching seal ring grooves on opposing flange faces.As shown in Figure 4, an outer jacket 408 is secured to the flange 404 and an outer collar 426 is secured to the jacket 408 which, via a radially inner surface of the jacket, seals against an outer surface of an outer sheath 170 of the flexible pipe body 100 via at least one outer seal ring 409 (an example of a seal ring element, as for the seal ring 340 discussed with reference to Figure 3). The outer jacket 408 and outer collar 426 are both examples of end fitting components. Optionally, the end fitting 312 may instead include a central flange that is connected or secured to the jacket 408 and a separate connector flange (for connecting the end fitting 312 to a further end fitting) via a neck region. In such an embodiment the flange 404 would become the central flange of the end fitting 312 and axially distil to the central flange, at the other end of the neck region, the separate connector flange would be configured, comprising a longitudinal terminal end region with flange-to-flange sealing features. As shown in Figure 4, a radially innermost surface of the jacket 408 is spaced apart from a radially outer surface of a generally cylindrical but slightly flared outwards end of an end fitting body 416 (an example of an end fitting component, as for the end fitting body 330 of Figure 3) of the end fitting. The end fitting 312 also includes a collar 418 (a further example of an end fitting component), which includes a flange portion and a neck portion, that is securable to the end fitting body 416, optionally via other elements of the end fitting. An open mouth 420 of the end fitting body faces an associated end region 304 of flexible pipe body. Tensile armour wires 422 are terminated in a tapered space 424 between the outer casing and the end fitting body. Aptly epoxy is located in the tapered space to entomb the ends of the tensile armour wires 422. The end fitting 312 is associated with a central longitudinal axis A-A and the central longitudinal axis of each end fitting is aligned along a common axis when the end fittings are arranged in a back-to-back configuration. During use production and injection fluids are transported along a bore provided by the barrier layer or liner of the flexible pipe body and the inner surface of each end fitting 312.

[0116] Figure 4 helps illustrate how the segment of flexible pipe body 100 includes a barrier layer 110 (an example of an inner pressure sheath, which is itself an example of a tubular polymer layer) that is sealed via at least one inner seal ring 430 that is an example of a seal ring element. Figure 4 further helps illustrate how the segment of flexible pipe body 100 includes a permeation retarding layer 122 radially around the barrier layer 110 and a sealed polymer layer 124 disposed radially around the permeation retarding layer 122. It will be appreciated that the permeation retarding layer 122 may be a layer of helically wound tape, which for clarity is represented at the interface between the barrier layer 110 and the sealed polymer layer 124. Optionally, no permeation retarding layer or sealed polymer layer are present. Figure 4 also helps show how the sealed polymer layer 124 is sealed in the end fitting 312 via at leastone intermediate seal ring 435 (two intermediate seal rings 435 are present in Figure 4) that is a further example of a seal ring element (as for the seal ring 340 described with reference to Figure 3). It will be appreciated how due to the respective sealing of the inner pressure sheath, the polymer layer and the outer sheath, two annulus regions are located in the segment of flexible pipe body 100. An inner annular region is located between the inner pressure sheath and the polymer layer, and an outer annular region is located between the polymer layer and the outer sheath. It will be appreciated that the segment of flexible pipe body includes a carcass layer 120 radially within the barrier layer 110. Optionally no carcass layer is included, in which case the inner pressure sheath is referred to as a liner.

[0117] As shown in Figure 4, one or more optional diagonal fluid port / ports 450, 490 can be arranged to extend through the inner collar from behind the inner seal ring. This port communicates with a fluid communication passageway (not shown in Figure 4) which passes through the body of the end fitting 416 to a venting region at an external surface of the end fitting. Thus, the inner annulus can be vented via this port and fluid communication passageway.

[0118] The outer annulus can be vented via a horizontal port which passes through the jacket and a through-hole in the outer collar 426, and exits to the front to the end fitting proximate to where the flexible pipe body enters the end fitting.

[0119] It will be appreciated that each of the seal rings 409, 430, 435 shown in Figure 4 may be examples of a seal ring element (as for the seal ring 340 of Figure 3). Each of these seal rings 409, 430, 435 simultaneously provide a first seal circumferentially around the outer surface of a respective tubular polymer layer and a further seal with an end fitting component (such as an end fitting body, end fitting outer jacket, end fitting outer collar, or end fitting inner collar) of the end fitting 312. As described with reference to Figure 3, this first (polymer-to-metal) seal and further (metal-to-metal) seal is provided upon energising of the respective seal ring by urging the respective arm portion of the seal ring radially inwardly and into biting engagement with the outer surface of the respective tubular polymer layer. It will be further appreciated that each of the seal rings 409, 430, 435 may include an annular seal element (for example, an annular recess described with reference to Figures 3-7 or a metal lip seal described with reference to Figures 8 and 9) that provides a still further seal. Therefore, the seal rings 409, 430, 435 may provide two axially and radially spaced apart seals between the respective seal ring and end fitting component as described herein. It will be appreciated that according to certain embodiments, the flexible pipe body may include a different configuration of layers(such as no permeation retarding layer and / or no sealed polymer layer), in which case the end fitting may include a different number or configuration of seal rings.

[0120] Figures 5a and 5b illustrate the end fitting 312 of Figure 4 in more detail. Figure 5a illustrates how intermediate seal rings 435, that are examples of seal ring elements, engage in a sealing manner against a radially outer surface of the sealed polymer layer 124 (an example of a tubular polymer layer) to thereby provide a sealed fluid retaining layer disposed between the outer sheath and the inner barrier layer (that themselves also constitute fluid retaining layers). It will be understood that Figure 5a illustrates an end region 304 of a segment of flexible pipe body 100 that is terminated in the end fitting 312 of Figure 4. As shown in Figure 5a, the intermediate seal rings 435 include a deformable portion 540 (an example of the arm portion 350 of the seal ring 340 of Figure 3) that is urged radially inwardly thus into intimate contact (that optionally is biting engagement) with the radially outer surface of the sealed polymer layer 124. It will be appreciated that each deformable portion is urged radially inwardly such that a radially inwards facing abutment surface disposed on a radially inner surface of the deformable portion is urged into intimate contact (that optionally is biting engagement) with the sealed polymer layer 124. Figure 5a helps illustrate how the deformable portion 540 of each intermediate seal ring 435 is urged inwardly via abutment of the deformable portion of each seal ring with a respective inner collar 544 (an example of an end fitting component) of the end fitting 312. As shown, each inner collar 544 includes a radially innermost facing abutment surface which is urged against a cooperating tapered collar abutment surface disposed on a radially outer surface of each deformable portion. Thus, as the inner collar 544 are urged against each of the intermediate seal rings 435, the deformable portion is urged radially inwardly due to the mating abutment surfaces of the respective inner collar 544 and seal rings. Each seal ring 435 also has an annular seal element 550 at a respective side face region, as described with reference to Figure 3. It will be appreciated that in Figure 5a, the annular seal element 550 is an annular recess, with a resilient metal seal disposed partially in the annular recess, but according to other embodiments the annular seal element 550 may be a metal lip seal (as described with reference to Figures 8 and 9).

[0121] Figure 5b helps illustrate how the outer collar 426 of the end fitting 312 of Figure 4 is secured to the outer jacket 408 by means of a screw 570, securing and retaining the outer seal ring 409 (an example of a seal ring element). It will be appreciated that the screw is an example of a fastening element, and may be one or more screws or bolts of the like. It will be appreciated that securement of the outer collar and the outer jacket urges the outer seal ring409 radially inwards to seal against the outer sheath. It will be further appreciated that the outer seal ring 409 may include an annular seal element as described herein.

[0122] The seal ring 340 of Figure 3 is further illustrated in Figures 6a and 6b. Figure 6a illustrates an end-on view of the seal ring 340, as schematically illustrated in partial cross-section in Figure 3. The seal ring 340 is an annular body, such that it is substantially ring-shaped from the end-on view and cylindrically symmetric around an imaginary centre axis 610 of the seal ring 340. It will be appreciated that, in use, the imaginary centre axis 610 of the seal ring 340 may be aligned with a central longitudinal axis of an end fitting component and / or tubular polymer layer. As can be seen in the end-on view of Figure 6a, the annular body of the seal ring 340 includes the body portion 345 and the arm portion 350, and the body portion 345 has the annular recess 385 (as an example of an annular seal element).

[0123] Figure 6b illustrates a cross-sectional view of the seal ring 340 of Figure 6a. The cross-sectional view of Figure 6b shows a cross-sectional view through the line B-B shown in Figure 6a, with an upper part and lower part of the annular body of the seal ring 340 shown and the connecting parts of the annular body represented by the dashed lines. It will be appreciated that the annular body extends around and is cylindrically symmetric about the imaginary centre axis 610. In the cross-sectional view, the arm portion 350 can be seen to extend away from the side face region 355 of the body portion 345. The arm portion 350 has a radially inwards facing abutment surface 360, facing towards the imaginary centre axis 610, and a radially outwards facing abutment surface 370, facing away from the imaginary centre axis 610. The arm portion 350 extends radially inwards from the body portion 345. The annular recess 385 (an example of an annular seal element) is located at the side face region 355, suitable to receive a resilient metal seal and with a depth 620 in the axial direction. The depth 620 may be, for example, in the range 0.5- 15 mm, optionally in the range 1 - 10 mm, further optionally in the range 2 -8 mm. The body portion 345 is substantially rectangular, with the straight back side face 397 substantially parallel to and spaced apart from regions of the side face region 355 that lie in a common plane and where the arm portion 350 and the annular recess 385 are not located. Additionally, the straight radially inner face portion 398 of the body portion 345 faces radially inwards and the straight radially outer face portion 399 of the body portion 345 faces radially outwards. Aptly, the straight radially inner face portion 398 is a whole of a radially inner facing surface of the body portion 345 and the straight radially outer face portion 399 is a whole of a radially outer facing surface of the body portion 345.The resilient metal seal 390 of Figure 3 is further illustrated in Figures 7a and 7b. The resilient metal seal 390 is an example of a resilient seal ring member. It will be appreciated that the resilient metal seal 390 is suitable to be located at least partially in the annular recess 385 of the seal ring 340 as described herein. Figure 7a illustrates an end-on view of the resilient metal seal 390 of Figure 3. The resilient metal seal 390 is a metal annular body and is substantially ring-shaped and cylindrically symmetric about an imaginary centre axis 710. It will be appreciated that when located at least partially at the annular recess 385 of the seal ring 340, the imaginary centre axis 710 may align with the imaginary centre axis 610 of the seal ring 340.

[0124] Figure 7b illustrates a cross-sectional view of the resilient metal seal 390 of Figure 7a. The cross-sectional view of Figure 7b shows a cross-sectional view through the line C-C shown in Figure 7a, with an upper part and lower part of the metal annular body of the resilient metal seal 390 shown and the connecting parts of the metal annular body represented by the dashed lines. It will be appreciated that the resilient metal seal 390 extends around and is cylindrically symmetric about the imaginary centre axis 710. In the cross-sectional view, the metal annular body of the resilient metal seal 390 is C shaped, with the open side of the C shape facing radially inwards towards the imaginary centre axis 710. It will be appreciated that according to other embodiments, the resilient metal seal 390 may have a different common cross section, such as O shaped, II shaped, V shaped, Y shaped, W shaped, or the like. As described herein, the shape of the resilient metal seal 390, with an open side of the respective shape (e.g. open side of a C shape, open side of a II shape, open side of a V shape or the like) facing radially inwards acts to provide an enhanced sealing effect upon an initial leakage, as an increase of differential pressure on the open side of the resilient metal seal 390 further deforms the resilient metal seal 390 by flaring out the sides of the resilient metal seal 390 to increase the pressure-energization force and provide an enhanced seal. A cross-sectional width 720 in an axial direction of the metal annular body of the resilient metal seal 390 may be, for example, in the range 0.5 - 30 mm, optionally in the range 1 -20 mm, further optionally in the range 4 - 15 mm. It will be appreciated that the cross-sectional width 720 is greater than the depth 620 of the annular recess 385 (shown in Figure 6b), such that in use metal annular body is compressed to a reduced cross-sectional width.

[0125] Figure 8 illustrates a schematic view of how at least one layer of a flexible pipe body can be sealed in an end fitting, as an alternative embodiment to those described with reference to Figures 3-7. Figure 8 illustrates a schematic view of an end region 304 of a segment of flexible pipe body 302. As for the embodiments described with reference to Figures 3-7, a seal ring840 (an example of a seal ring element) simultaneously provides a first seal circumferentially around an outer surface 320 of the inner pressure sheath 315 and a further seal with an end fitting body 330 (an example of an end fitting component) of an end fitting 312 of a flexible pipe. It will be appreciated that the elements of Figure 8 other than the seal ring 840 are as described with reference to Figures 3-7.

[0126] The seal ring 840 is an annular body as further illustrated in Figures 9a and 9b. In a cross section shown in Figure 8, the seal ring 840 has a body portion 845 and an arm portion 850, where the arm portion 850 extends away from a side face region 855 of the body portion 845. That is to say, the arm portion 850 is an arm-shaped extension of the seal ring 840, i.e. projects from the side face region 855 of the body portion 845, as for the arm portion 345 of the seal ring 340 of Figure 3. The arm portion 850 has a radially outwards facing abutment surface 870.

[0127] In contrast to the seal ring 340 of Figure 3, the seal ring 840 has a metal lip seal 885 (an example of a resilient protuberance that is an annular seal element) at the side face region 855 located radially outside the radially outwards facing abutment surface 870. The metal lip seal 885 extends circumferentially around the body portion (as shown in Figures 9a and 9b) and away from the side face region 855. In Figure 8, the metal lip seal 885 is integrally formed with the body portion 845, but according to other embodiments the metal lip seal 885 may be secured to the body portion by fastening means such as bolts or clips the like. The metal lip seal 885 may be made from the same material as the seal ring 840 (e.g. steel), or may be made from a different material such as one of the various stainless steels and / or nickel alloys described with reference to the resilient metal seal 390.

[0128] The metal lip seal 885 is arcuate in cross section (i.e. curved) and has a free end 887 that is radially more proximate to an imaginary centre axis of the seal ring 840 than a root region 888 where the metal lip seal 885 starts to extend outwards at the side face region 855. It will be appreciated that the metal lip seal 885 help provides a backup seal in a similar manner as described previous for the resilient metal seal 390 of Figures 3-7, where the metal lip seal is dipped radially inwards towards an imaginary centre axis of the seal ring 840. According to some embodiments, at the root portion 888 of the lip seal proximate to the body portion 845, the angle of inclination of the metal lip seal 885 is between 50 to 70 degrees, where the angle is measured with respect to an imaginary plane containing regions of the side face region 855 where the metal lip seal 885 and the arm portion 850 are not located and that lie in a common plane. It will be appreciated that an arc-angle of the metal lip seal 885 may be 120 - 180° fromthe imaginary plane containing regions of the side face region 855. That is to say, the metal lip seal 885 may be configured to have a substantially U-shape to minimise any risk of stress concentration and folding of the lip seal 885. It will be further appreciated that the end fitting body 330 has an annular recess suitable for receiving the metal lip seal 885, with a depth in the axial direction of less than an uncompressed cross-sectional width in the axial direction of the metal lip seal 885. Thereby, in use, the seal ring 840 is urged axially towards the end fitting body 330 causing the metal lip seal 885 to be urged against the secondary annular sealing surface region 395 at the open mouth zone 375 of the end fitting body 330. This causes deformation and compression of the metal lip seal 885 (similarly as described with respect to the resilient metal seal 390 of Figures 3-7), providing a still further seal, similarly as described with respect to Figure 3. That is to say, the still further seal provided by the metal lip seal 885 creates two axially and radially spaced apart seals between the seal ring 840 and the end fitting body 330, providing a back-up seal in case of failure of the further seal.

[0129] The arcuate configuration of the metal lip seal 885 may also provide an enhanced sealing effect upon an initial leakage, as previously described with respect to Figure 3. That is to say, an increase in pressure on the radially inner side of the metal lip seal 885 may cause further deformation of the metal lip seal 885, such that the sealing effect of the still further seal is improved.

[0130] The seal ring 840 of Figure 8 is further illustrated in Figures 9a and 9b. Figure 9a illustrates an end-on view of the seal ring 840 schematically shown in Figure 8. The seal ring 840 is an annular body, such that it is substantially ring-shaped from the end-on view and cylindrically symmetric around an imaginary centre axis 910 of the seal ring 840. It will be appreciated that, in use, the imaginary centre axis 910 of the seal ring 840 may be aligned with a central longitudinal axis of an end fitting and / or tubular polymer layer (e.g. an inner pressure sheath). As can be seen in the end-on view of Figure 9a, the annular body of the seal ring 840 includes the body portion 845 and the arm portion 850, and the body portion 845 has the metal lip seal 885 (an example of resilient protuberance that is an annular seal element).

[0131] Figure 9b illustrates a cross-sectional view of the seal ring 840 of Figure 9a. The cross-sectional view of Figure 9b shows a cross-sectional view through the line D-D shown in Figure 9a, with an upper part and lower part of the annular body of the seal ring 840 shown and the connecting parts of the annular body represented by the dashed lines. It will be appreciated that the annular body extends around and is cylindrically symmetric about the imaginary centre axis 910. In the cross-sectional view, the arm portion 850 can be seen to extend away fromthe side face region 855 of the body portion 845. The arm portion 850 has a radially inwards facing abutment surface 960, facing towards the imaginary centre axis 910, and the radially outwards facing abutment surface 870, facing away from the imaginary centre axis 910. The arm portion 850 extends radially inwards from the body portion 845.

[0132] The metal lip seal 885 (a resilient protuberance that is an example of an annular seal element) is located at the side face region 855, and with a depth 920 in the axial direction. The depth 920 may be, for example, in the range 0.5 - 30 mm, optionally in the range 1 -20 mm, further optionally in the range 4 - 15 mm. As described with reference to Figure 8, the resilient protuberance 885 is arcuate in cross section and dipped radially inwards to provide a metal lip seal in use. The body portion 845 is substantially rectangular, with the straight back side face 997 substantially parallel to and spaced apart from regions of the side face region 855 that lie in a common plane and where the arm portion 850 and the metal lip seal 885 are not located. Additionally, the straight radially inner face portion 998 of the body portion 845 faces radially inwards and the straight radially outer face portion 999 of the body portion 845 faces radially outwards. Aptly, the straight radially inner face portion 998 is a whole of a radially inner facing surface of the body portion 845 and the straight radially outer face portion 999 is a whole of a radially outer facing surface of the body portion 845.

[0133] Figure 10 illustrates a schematic view of how the activation of certain seals in an end fitting 1012 can be tested, in a testing configuration. It will be appreciated that the testing configuration shown in Figure 10 is illustrated for the seal ring 340 of Figures 3-7, but that the testing configuration is applicable for other embodiments, including for example the seal ring 840 of Figures 8-9, that have a first seal and further seal provided between an end fitting component for a flexible pipe and a common seal ring at respective spaced apart locations.

[0134] The seal ring 340 has elements as described with reference to Figures 3-7, in particular the seal ring 340 has the body portion 345, arm portion and annular recess 385, with the resilient metal seal 390 located at least partially at the annular recess 385. As previously described, the radially outwards facing surface 370 of the arm portion 350 of the seal ring 340 provides a first seal with an outwardly flared annular surface 1035 at an open mouth end 1037 of an end fitting body 1030 (an example of an end fitting component). It will be appreciated that the first seal is a metal-to-metal sealing region. A further seal is provided via the resilient metal seal 390 (an example of a resilient element) disposed between the end fitting body 1030 and the body portion 450 of the seal ring 340. The metal lip seal 885 of Figure 8 is an alternative example of a resilient element.As described herein, the further seal provided by the resilient element (in this case the resilient metal seal 385) acts as a back-up seal in case of failure of the first seal provided by the radially outwards facing surface 370 of the arm portion 350. A fluid communication passageway 1050 extends through the end fitting body 1030 and terminates at the interface between the end fitting body 1030 and seal ring 340, between the resilient metal seal 390 (or other resilient element) located at least partially at the annular recess 385 and the radially outwards facing surface 370 of the arm portion 350. It will be appreciated that the fluid communication passageway 1050 allows for a predetermined test pressure to be applied between the first seal and further seal.

[0135] The fluid communication passageway 1050 allows for testing activation of the first seal and further seal by, subsequent to application of the predetermined fluid test pressure, repeatedly or after a preset period of time, determining a fluid pressure associated with an end 1060 of the fluid communication passageway 1050. For example, the fluid pressure at the end 1060 of the fluid communication passageway 1050 may be determined periodically or after the preset period of time. The end 1060 of the fluid communication passageway 1050 is located at a radially outer surface of the end fitting body relative to the location of the inner pressure sheath 315 (an example of a tubular polymer layer), as further illustrated in Figure 11. It will be appreciated that if the first seal and further seal are both providing effective seals then the predetermined fluid test pressure may not substantially decrease with time, as the action of the first seal and further seal do not allow for dissipation of the predetermined fluid test pressure. Alternatively, decrease of the fluid pressure over time may indicate failure of either or both of the first seal and further seal. In this way, activation of the first seal and further seal may be tested by the testing configuration shown in Figure 10.

[0136] It will be appreciated that the predetermined fluid test pressure may be applied subsequent to sliding the seal ring 340 along the cylindrical outer surface 320 of the inner pressure sheath 315 (or other tubular polymer layer) of flexible pipe body against the open mouth zone 1037 of the end fitting body 1030. That is to say, the seal ring 340 may first be urged against the respective surfaces of the end fitting body 1030, such that the first seal and further seal are activated, before applying the predetermined fluid test pressure to test activation of the first seal and further seal. Additionally, the predetermined fluid test pressure may be applied either before or after securing an outer jacket (an alternative example of an end fitting component) to the end fitting body 1030 as a step during termination of the flexible pipe body, depending on where the seal ring 340 is located within the end fitting, as described further with referenceto Figure 11. That is to say, for certain seal rings 340 the predetermined fluid test pressure may be applied at an intermediate stage during termination of the flexible pipe body, before securing an outer jacket to the end fitting body 1030, when the end 1060 of the respective fluid communication passageway 1050 is accessible. Alternatively, for certain radially outer seal rings 340, the end 1060 of the respective fluid communication passageway 1050 may be at an exterior surface of the end fitting and accessible following termination of the flexible pipe body, and hence the predetermined fluid test pressure may be applied after securing an outer jacket to the end fitting body 1030.

[0137] Figure 11 illustrates a cross-sectional view of a segment of flexible pipe body 100 that is terminated in an end fitting 1112. It will be appreciated that the end fitting 1112 shown in Figure 11 is substantially the same as the end fitting 312 shown in Figure 4 with components and elements as described with reference to Figure 4. The difference between the end fitting 1112 and the end fitting 312 shown in Figure 4 is the presence of fluid communication passageways 1150 to allow for testing activation of the first seal and further seal as described with reference to Figure 10. As for the end fitting 312 of Figure 4, the end fitting 1112 may be usable to terminate flexible pipe body that has a diameter of around 6 inches or the like. Alternative arrangements or configurations of end fitting may be used according to certain other embodiments.

[0138] As described with reference to Figure 10, the fluid communication passageways 1150 extend through the respective inner collar (examples of an end fitting component), from an end 1160 at a radially outer surface of the respective inner collar relative to the location of the sealed polymer layer 124 (an example of a tubular polymer layer) to respective intermediate seal rings 435 (examples of a seal ring element). It will be appreciated that fluid communication passageways may alternatively be provided to seal rings located at different locations within the end fitting, with the fluid communication passageway extending through the respective end fitting component. Each seal ring 435 has an annular seal element as described herein, for example an annular recess or resilient protuberance. Each fluid communication passageway 1150 therefore allows for testing activation of a first seal and a further seal provided between the respective end fitting inner collar (or other end fitting component) and the common seal ring 435 as described with reference to Figure 10, by first applying a predetermined fluid test pressure and then, repeatedly or after a preset period of time, determining a fluid pressure associated with the respective end 1160 of the fluid communication passageway 1150. It will be appreciated that applying the predetermined fluid test pressure may be subsequent to sliding the seal ring 435 along the cylindrical outer surface of the sealed polymer layer 124against an open mouth zone of the inner collar and thereby activating, or attempting to activate, the first and further seal.

[0139] It will be appreciated that in the embodiment shown in Figure 11, the end 1160 of each fluid communication passageway 1150 is located at an interior region of the end fitting 1112. That is to say, in a fully assembled state of the end fitting, the end 1160 of each fluid communication passageway 1150 is covered by other components of the end fitting 1112, such as the outer jacket 408. In this case, the end 1160 of each fluid communication passageway 1150 may only be accessible at an intermediate stage of termination of the flexible pipe body, i.e. when the end fitting 1112 is partially assembled, and testing activation of the first seal and the further seal may therefore be carried out at such an intermediate stage, for example before securing the outer jacket 408 to the end fitting body.

[0140] According to certain other embodiments, a fluid communication passageway may be provided that extends through a respective end fitting component (e.g. the end fitting body) to an end located at an exterior surface of the end fitting 1112, such that the end is accessible after fully assembling the end fitting 1112. Testing activation of the first seal and the further seal may therefore be carried out following termination of the flexible pipe body, for example after securing the outer jacket 408 to the end fitting body. It will be appreciated that such a fluid communication passageway with an end accessible after fully assembling the end fitting 1112 may be provided by appropriately configuring the fluid communication passageway. By way of example only, for the inner seal ring 430 such a fluid communication passageway may have a radial portion that extends radially outwards through the end fitting body 416, radially away from the seal ring 450, connected to an axial portion that extends in an axial direction through the end fitting body 416 towards the end face of the flange 404. The end of such a fluid communication passageway may be located at the end face of the flange 404 and accessible after securing the outer jacket 408, or the axial portion of the fluid communication passageway may connect to a further radial portion that extends radially outwards through the flange 404 with the end located at a radial outer surface of the flange 404.

[0141] Figure 12 is a flow diagram that represents a method 1200 of terminating flexible pipe body. The method 1200 is applicable with any of the embodiments described herein, including the flexible pipe body 100 of Figure 1, a seal ring element (such as the seal ring 340 of Figures 3-7 or the seal ring 840 of Figures 8-9), and an end fitting component (such as the end fitting body 330 of Figure 3 or the end fitting body 1030 of Figure 10).In an initial step 1210, a segment of flexible pipe body (such as the flexible pipe body 100 shown in Figure 1) is provided for termination and sealing of the respective layers as described herein. The initial step 1210 includes providing at least a tubular polymer layer (e.g. an inner or outer pressure sheath) of the segment of flexible pipe body to an open mouth zone of an end fitting component (such as an end fitting body, outer jacker, or inner or outer collar) of a flexible pipe end fitting. It will be appreciated that in the initial step 1210 a respective seal ring may be located over each tubular polymer layer of the segment of flexible pipe body. The tubular polymer layer may be the inner pressure sheath 315 shown in preceding figures, or alternatively may be a different tubular polymer layer of the segment of flexible pipe body 100, such as the outer sheath 170. The end fitting component may be, for example, the end fitting body 330 of Figure 3 or the end fitting body 1030 of Figure 10.

[0142] Next, in an urging step 1220, the respective seal ring that was previously disposed over the tubular polymer layer is urged against the end fitting component. The seal ring may be any of the embodiments of a seal ring element described herein. It will be appreciated that the urging step 1220 may be achieved, for example, as shown in Figures 5a and 5b, with securement of a collar and jacket by means of fastening elements causing urging of the respective seal ring radially inwards to seal against the tubular polymer layer and end fitting component.

[0143] Then, in a sealing step 1230, a first seal between the end fitting component and the seal ring is provided via a radially outwards facing abutment surface of the seal ring and a further seal between the end fitting component and the seal ring is also provided via an annular seal element at a side face region of the seal ring that is disposed radially outside (i.e. further from an imaginary centre axis of the seal ring element) the radially outwards facing abutment surface. It will be appreciated that, as described herein, the first seal may be provided by urging a radially outwards facing abutment surface of an arm portion of the seal ring against an outwardly flared annular surface at an open mouth zone of the end fitting component to form a metal-to-metal sealing region. The first seal and the further seal may be provided simultaneously as the seal ring is urged against the end fitting component responsive to the urging step 1220, or the first seal and the further seal may be provided sequentially (in either order) as the abutment of respective surfaces occurs.

[0144] According to certain embodiments as described herein, the annular seal element may be an annular recess in the side face region of the seal ring, with a resilient metal seal (an example of a resilient seal ring member) disposed at least partially in the annular recess. The further seal may therefore be provided by urging the resilient metal seal against a surface of the endfitting component. It will be appreciated that the surface of the end fitting component may be within a secondary annular recess arranged to receive the resilient metal seal. The further seal may thus be activated due to the deformation of the resilient metal seal against the end fitting component.

[0145] According to certain other embodiments as described herein, the annular seal element may be a metal lip seal (an example of a resilient protuberance) that extends circumferentially around a body portion of the seal ring and away from the side face region of the seal ring. The further seal may therefore be provided by urging the metal lip seal against a surface of the end fitting component. It will be appreciated that the surface of the end fitting component may be within a secondary annular recess arranged to receive the metal lip seal. The further seal may thus be activated due to the deformation of the metal lip seal against the end fitting component.

[0146] 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.

[0147] Features, integers, characteristics 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 the features and / or steps are mutually exclusive. The invention is not restricted to any details of any foregoing embodiments. The invention extends to any novel one, or 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.

[0148] 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 topublic inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

- 37 - 52WS-511107-WO-2CLAIMS:

1. A seal ring element for simultaneously providing a first seal circumferentially around an outer surface of a tubular polymer layer and a further seal with an end fitting component of an end fitting of a flexible pipe, comprising:an annular body that has a cross section comprising a body portion, an arm portion, extending away from a side face region of the body portion, that comprises a radially inwards facing abutment surface and a radially outwards facing abutment surface, and an annular seal element at the side face region disposed radially outside the radially outwards facing abutment surface.

2. The seal ring element as claimed in claim 1, further comprising:the annular seal element comprises an annular recess in the side face region and the seal ring element further comprises a resilient seal ring member disposed at least partially in the annular recess.

3. The seal ring element as claimed in claim 2, further comprising:the resilient seal ring member comprises a metal annular body that has a common cross section around a whole circumference of the metal annular body and optionally the metal annular body includes a coating material that coats a whole or at least one region of the metal annular body.

4. The seal ring element as claimed in claim 2 or claim 3, further comprising:a cross-sectional width in an axial direction of the metal annular body is greater than a depth in the axial direction of the annular recess in the side face region.

5. The seal ring element as claimed in claim 1, further comprising:the annular seal element comprises a resilient protuberance that extends circumferentially around the body portion and away from the side face region and that is secured to or is integrally formed with the body portion.

6. The seal ring element as claimed in claim 5, further comprising:the resilient protuberance is arcuate in cross section and has a free end that is radially more proximate to an imaginary centre axis of the seal ring element than a root region where the protuberance starts to extend outwards at the side face region.- 38 - 52WS-511107-WO-27. The seal ring element as claimed in claim 5 or claim 6, further comprising:the resilient protuberance provides a metal lip seal that is dipped radially inwards towards an imaginary centre axis of the seal ring element and that optionally is inclined at an angle of between 50 degrees to 70 degrees at a root portion of the lip seal proximate to the body portion, wherein the angle is with respect to an imaginary plane containing regions of said a side face region where the annular seal element and the arm portion are not located and that lie in a common plane.

8. The seal ring element as claimed in any preceding claim, further comprising:in said a cross section, the body portion is rectangular and has a straight back side face disposed in a spaced apart substantially parallel relationship with regions of said a side face region where the annular seal element and the arm portion are not located and that lie in a common plane.

9. The seal ring element as claimed in any preceding claim, further comprising:in said a cross section, the body portion has a straight radially inner face portion and a straight radially outer face portion and optionally the straight radially inner face portion comprises a whole of a radially inner facing surface of the body portion and the straight radially outer face portion comprises a whole of a radially outer facing surface of the body portion.

10. The seal ring element as claimed in any preceding claim, further comprising:the radially inwards facing abutment surface is locatable against a cylindrical outer surface of a tubular polymer layer for providing a first seal therebetween; and the radially outwards facing abutment surface is locatable against a primary annular sealing surface region at an open mouth zone of an end fitting component for providing a further seal therebetween.

11. The seal ring element as claimed in any preceding claim, further comprising:the annular seal element is a recess holding a resilient seal ring member or is a circumferentially extending resilient protuberance and the resilient seal ring member or resilient protuberance is for providing a still further seal when urged against a secondary annular sealing surface region at an open mouth zone of an end fitting component.

12. The seal ring element as claimed in any preceding claim, further comprising:the annular body is locatable in an open mouth zone of an end fitting component and is urgeable against the end fitting component to provide two axially and radially spaced apart seals therebetween, and optionally the end fitting component is an end fitting body or end fitting jacket or inner or outer collar.

13. A method of testing activation of a first seal and a further seal provided between an end fitting component for a flexible pipe and a common seal ring element at respective spaced apart locations, comprising:via a fluid communication passageway that extends through an end fitting component for a flexible pipe, applying a predetermined fluid test pressure between a first seal, provided by a radially outwards facing surface of an arm portion of a seal ring element and an outwardly flared annular surface at an open mouth end of the end fitting component, and a further seal provided via a resilient element disposed between the end fitting component and a body portion of the seal ring element.

14. The method as claimed in claim 13, further comprising:subsequent to application of the predetermined fluid test pressure, repeatedly or after a preset period of time, determining a fluid pressure associated with an end of the fluid communication passageway.

15. The method as claimed in claim 13 or claim 14, further comprising:applying the predetermined fluid test pressure subsequent to sliding the seal ring element along a cylindrical outer surface of a tubular polymer layer of flexible pipe body against an open mouth zone of the end fitting body and before or after securing an outer jacket to an end fitting body as a step during termination of a flexible pipe body, wherein optionally the end fitting component comprises the end fitting body or the outer jacket.

16. A method of terminating flexible pipe body, comprising:providing an end of at least a tubular polymer layer of a segment of flexible pipe body in an open mouth zone of an end fitting component of a flexible pipe end fitting;urging a seal ring element previously disposed over the tubular polymer layer against the end fitting component;providing a first seal between the end fitting component and the seal ring element via a radially outwards facing abutment surface of the seal ring element; and providing a further seal between the end fitting component and the seal ring element via an annular seal element at a side face region of the seal ring element that is disposed radially outside the radially outwards facing abutment surface.

17. The method as claimed in claim 16, further comprising:providing the further seal and the first seal simultaneously as the seal ring element is urged against the end fitting component.

18. The method as claimed in any one of claims 16 or 17, further comprising:providing the first seal by urging a radially outwards facing abutment surface of an arm portion of an annular body of the seal ring element against an outwardly flared annular surface at an open mouth zone of the end fitting component.

19. The method as claimed in any one of claims 16 to 18, further comprising:providing the further seal by urging a resilient seal ring member, that is at least partially disposed in an annular recess, in the side face region, that provides the annular seal element, against a surface of the end fitting component; and deforming the resilient seal ring member against the end fitting component thereby activating the further seal, wherein optionally the end fitting component is an end fitting body or end fitting jacket or end fitting inner or outer collar.

20. The method as claimed in any one of claims 16 to 18, further comprising:providing the further seal by urging a resilient protuberance, that extends circumferentially around a body portion of the seal ring element and away from a side face region of the seal ring element, against a surface of the end fitting component; anddeforming the resilient protuberance against the end fitting component thereby activating the further seal, wherein optionally the end fitting component is an end fitting body or end fitting jacket or end fitting inner or outer collar.

Images