WO2019239116A1

WO2019239116A1 - Captive wire securement

Info

Publication number: WO2019239116A1
Application number: PCT/GB2019/051611
Authority: WO
Inventors: Richard Alasdair Clements
Original assignee: Ge Oil & Gas Uk Limited
Priority date: 2018-06-13
Filing date: 2019-06-10
Publication date: 2019-12-19
Also published as: GB201809674D0

Abstract

A method and apparatus for securing an end region of a tensile armour wire within a flexible pipe end fitting and a method of terminating flexible pipe body in an end fitting are disclosed. The apparatus comprises a rigid housing comprising at least one anchoring surface and partially enclosing a chamber region, at least one captive element, within the chamber region, that is moveable away from an inlet opening in the housing when a free end region of a tensile armour wire is urged through the inlet opening into the housing, and towards the inlet opening when a tensile armour wire is pulled out from the inlet opening away from the housing. The chamber region comprises a tapered zone having a narrow end region proximate to the inlet opening that receives the captive element when it is moved towards the inlet opening for preventing subsequent movement of the housing with respect to the tensile armour wire in a direction towards a free end of the tensile armour wire.

Description

CAPTIVE WIRE SECUREMENT

The present invention relates to a method and apparatus for helping secure ends of armour wire of a flexible pipe within an end fitting. In particular, but not exclusively, the present invention relates to the addition of easy attaching securing elements on ends of tensile armour wires of a flexible pipe, prior to their submersion in epoxy resin, as part of a pipe body termination operation. Affixing a body to the wire provides anchoring points that help prevent extraction of the wire from the epoxy region during later use of the flexible pipe. Using a captive element like a roller or ball in a rigid housing lets wire be threaded easily into the housing but prevents backwards motion of the wire once the housing is at a desired location.

Traditionally flexible pipe is utilised to transport production fluids, such as oil and/or gas and/or water, from one location to another. Flexible pipe is particularly useful in connecting a sub-sea location (which may be deep underwater, say 1000 metres or more) to a sea level location. The pipe 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). A flexible pipe is generally formed as an assembly of flexible pipe body and one or more end fittings. The pipe body is typically formed as a combination of layered materials that form a pressure-containing conduit. The pipe structure allows large deflections without causing bending stresses that impair the pipe’s functionality over its lifetime. There are different types of flexible pipe such as unbonded flexible pipe which is manufactured in accordance with API 17J or composite type flexible pipe or the like. The pipe body is generally built up as a combined structure including polymer layers and/or composite layers and/or metallic 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.

Some flexible pipe has been used for deep water (less than 3,300 feet (1 ,005.84 metres)) and ultra-deep water (greater than 3,300 feet) developments. It is the increasing demand for oil which is causing exploration to occur at greater and greater depths (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 pipe conventionally is designed to perform at operating temperatures of -30°C to +130°C, and is being developed for even more extreme temperatures. Increased depths also increase the pressure associated with the environment in which the flexible pipe must operate. For example, a flexible pipe may be required to operate with external pressures ranging from 0.1 MPa to 30 MPa acting on the pipe. Equally, transporting oil, gas or water may well give rise to high 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 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.

When flexible pipe body is terminated at each end with an end fitting it is known that the various layers within the flexible pipe body must be separately cut and sealed as part of a termination process. Conventionally tensile armour wires which are wires helically wound along a length of the flexible pipe body are terminated in a complicated and therefore costly manner. Typically each tensile armour wire (there may be up to a hundred or more) must be bent away from a bore region of the flexible pipe body without overbending and then each armour wire must be cut to an appropriate length. The bending is required to access the ends of all of the tensile armour wires in the flexible pipe body to apply a crimp which thereafter helps anchor and thereby secure the wires in the end fitting. The bending back operation is dangerous as the wires splay around 360 degrees in a plane perpendicular to an axis of the pipe. The crimping of the wires is also potentially damaging to the wires as it requires very high levels of local deformation. Some methods of crimping may also attempt to stretch the wire which may sometimes result in wire breakage. Furthermore, a containment space (a volume) required for the crimped wires in the end fitting void space (which is later filled with a curable material such as an epoxy potting compound or the like) is also fairly large due to the build-up of space required with all adjacent and overlying crimped wires around the body of the end fitting. This results in a larger and thus heavier termination end fitting body being required which thereafter is difficult to handle.

After bending, the ends of the tensile armour wires are conventionally fixed in place with respect to the remainder of the end fitting by locating the crimped tensile armour wire ends in a void space within the end fitting which is filled with epoxy resin as part of the termination process. As the curable epoxy solidifies the armour wire ends are interred within the epoxy material. Often this results in an adequate securing mechanism for securing end regions of tensile armour wire within an end fitting. However, as noted above, the process is time consuming, can be dangerous, is costly and furthermore is occasionally prone to tensile armour wires, which are under significant tensile stress in use, pulling free from the epoxy. This is because conventionally the epoxy only acts for frictional purposes against an outer (generally smooth) surface of any tensile wire.

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

It is an aim of certain embodiments of the present invention to help increase an extraction force needed to extract each and every (or at least some) tensile armour wire from an epoxied region within an end fitting.

It is an aim of certain embodiments of the present invention to help provide a mechanism whereby extraction of tensile armour wires from a desired position within an end fitting can be avoided wholly or at least partially.

It is an aim of certain embodiments of the present invention to provide an anchoring mechanism for helping to secure an end region of a tensile armour wire within an end fitting/termination in a manner which is cost effective and which is efficient for human operators involved in an end fitting operation to carry out and which results in an effective anchoring effect to secure wires in a desired location.

According to a first aspect of the present invention there is provided apparatus for securing an end region of a tensile armour wire within a flexible pipe end fitting, comprising:

a rigid housing comprising at least one anchoring surface and partially enclosing a chamber region;

at least one captive element, within the chamber region, that is moveable away from an inlet opening in the housing when a free end region of a tensile armour wire is urged through the inlet opening into the housing, and towards the inlet opening when a tensile armour wire is pulled out from the inlet opening away from the housing; wherein

the chamber region comprises a tapered zone having a narrow end region proximate to the inlet opening that receives the captive element when it is moved towards the inlet opening for preventing subsequent movement of the housing with respect to the tensile armour wire in a direction towards a free end of the tensile armour wire.

Aptly the rigid housing comprises a first wall region that provides a first inner abutment surface of the housing that at least partially defines the chamber region; a further wall region that provides a further inner wall abutment surface region that is inclined with respect to the first inner abutment surface region to define a tapered zone therebetween.

Aptly the narrow end of the tapered zone narrows to a predetermined width at an end of the tapered zone proximate to said inlet opening, said predetermined width corresponding to a thickness dimension of a tensile armour wire plus an associated width dimension of the captive element minus a contraction distance of between 0.02 and 1 .00 mm.

Aptly the narrow end of the tapered zone has a width of between 7 and 18 mm.

Aptly the inlet opening is a through slot in an end of the rigid housing.

Aptly the rigid housing further comprises an outlet opening in the housing through which a free end of the tensile armour wire can be urged to thereby thread the rigid housing over a free end region of the tensile armour wire.

Aptly the rigid housing comprises a material that has a hardness greater than 12 HRc.

Aptly the hardness is greater than 30 HRc and is optionally greater than 40 HRc.

Aptly the captive element is at least one spherical ball or a roller body having a substantially cylindrical outer surface.

Aptly the captive element further comprises dimples, protrusions or knurling around its outer surface.

Aptly the captive element comprises a material that has a hardness greater than 12 HRc. Aptly the hardness is greater than 30 HRc and optionally is greater than 40 HRc.

Aptly the captive element comprises a metallic material or a ceramic material. Aptly the rigid housing is securable to the free end region so strongly that wire breaks under tensile loading before the housing pulls from the wire.

According to a second aspect of the present invention there is provided a method of securing an end region of at least one flexible pipe body tensile armour wire to an anchoring element, comprising the steps of:

urging a free end region of a tensile armour wire into a rigid housing that comprises at least one anchoring surface and, as the tensile armour wire is urged into the housing, moving a captive element in a chamber region of the housing away from an inlet opening of the housing; and

subsequently, via movement of the tensile armour wire, moving the captive element towards the inlet opening thereby driving the captive element into a generally tapered zone of the chamber region until subsequent movement of the housing with respect to the tensile armour wire in a direction towards a free end of the tensile armour wire is prevented.

Aptly the method further comprises urging the free end region by threading a free end of a tensile armour wire through the inlet opening in a first end of the rigid housing and through an outlet opening in a remaining end of the rigid housing whereby the housing and associated anchoring surface slides along the free end region of the tensile armour wire to a desired location a predetermined distance from the free end.

According to a third aspect of the present invention there is provided a method of terminating flexible pipe body in an end fitting, comprising the steps of:

providing an end fitting body comprising a connecting flange at a first end fitting end and an open mouth at a further end fitting end;

urging a free end region of each tensile armour wire, of a plurality of tensile armour wires, in an inwards direction through an inlet opening in a respective rigid housing that comprises at least one anchoring surface thereby moving a captive element in the housing away from said inlet opening to allow wire to enter the chamber region;

subsequently moving the captive element towards said inlet opening via movement of the rigid housing towards the free end of the tensile armour wire thereby driving the captive element into a tapered zone of the chamber region until subsequent withdrawal of the tensile armour wire from the rigid housing is prevented; securing a jacket member to the end fitting body thereby providing a cavity void region in the end fitting where respective end regions of the plurality of tensile armour wires and associated rigid housings and respective anchoring surfaces are located; and

subsequently providing a curable material in the cavity void region.

Aptly the method further comprises moving the captive element towards said inlet opening by subsequently urging the tensile armour wire in a reverse direction with respect to the housing to thereby move the captive element towards said inlet opening thereby locating the captive element at a narrow end of a generally tapered zone of the chamber region where the captive element is prevented from moving further towards the inlet opening and is urged against the armour wire as the armour wire is pulled out from the inlet opening thereby preventing motion of the wire away from the housing.

Aptly the method further comprises applying a load to the tensile armour wire of at least 50% of the structural capacity of the tensile armour wire to thereby confirm that the rigid housing and associated anchoring surface is secured at a desired location.

Aptly the method further comprises subsequently curing the material and thereby anchoring the tensile armour wire end regions in the cured material in the pocket region via the rigid housings on each tensile armour wire end region.

Certain embodiments of the present invention provide a cost effective solution for securing ends of tensile armour wire in an epoxied region within an end fitting. Securing bodies which can be threaded over each wire are provided and each of these helps anchor a respective wire in position and can be readily utilised by an operator.

Certain embodiments of the present invention provide securing bodies which are cheap to manufacture and which are easy to use as anchoring points.

Certain embodiments of the present invention provide a mechanism by which one or more elements can be fixed on a tensile armour wire to increase its effective cross-section at specific locations along its length. The anchoring mechanism may be provided as rigid housings secured on each wire with at least one captive element that automatically moves into an operative state, whereby removal of a housing from an outer surface of a tensile armour wire is restricted once the housing is located at a desired location. Certain embodiments of the present invention provide for the application of slotted and/or slitted housings onto tensile armour wires. Each of the housings can be threaded onto a free end of a respective tensile armour wire and a captive element in the housing can move to both allow the housing to be mounted onto a wire but also to stop the housing being subsequently withdrawn off the wire. This helps provide an easier and quicker and safer anchoring operation to help secure a tensile armour wire in an end fitting than is currently available with conventional techniques.

Certain embodiments of the present invention provide securing element bodies in the forms of slotted and/or slit housings which can slide onto wires up to a set distance. Optionally a small single depression or catch may be located at a narrow end of a tapered zone within the housing. This locates a captive element in a“locked” position once a desired position of a housing on a wire has been reached.

Certain embodiments of the present invention will now be described hereinafter, by way of example only, with reference to the accompanying drawings in which:

Figure 1 illustrates flexible pipe body;

Figure 2 illustrates certain uses of a flexible pipe;

Figure 3 helps illustrate an end of a flexible pipe where flexible pipe body is terminated in an end fitting;

Figure 4 illustrates a rigid housing threaded onto a tensile armour wire and a captive element;

Figure 5 illustrates a rigid housing on an end region of a tensile wire;

Figure 6 illustrates an alternative rigid housing;

Figure 7 illustrates an alternative rigid housing; and

Figure 8 illustrates an alternative rigid housing.

In the drawings like reference numerals refer to like parts. 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 and associated end fittings of the type which is manufactured according to API 17J. Such flexible pipe is often referred to as unbonded flexible pipe. Other embodiments are associated with other types of flexible pipe.

Turning to Figure 1 it will be understood that the illustrated flexible pipe is an assembly of a portion of pipe body and one or more end fittings (not shown) 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. As noted above 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.

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.

The pipe body 100 illustrated in Figure 1 includes an internal pressure sheath 1 10 which acts as a fluid retaining layer and comprises a polymer layer that ensures internal fluid integrity. 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 internal pressure sheath is often referred to by those skilled in the art as a barrier layer. In operation without such a carcass (so-called smooth bore operation) the internal pressure sheath may be referred to as a liner. A barrier layer 1 10 is illustrated in Figure 1 .

It is noted that the 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 internal pressure sheath 1 10 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. A carcass layer is radially positioned within the barrier layer.

The pressure armour layer 130 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 internal 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 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. The flexible pipe body 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, for instance 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 are formed from a composite, polymer, or other material, or a combination of materials.

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. The tape layer may optionally be a polymer or composite 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”.

The flexible pipe body also includes optional layers of insulation 165 and an outer sheath 170, which comprises a polymer layer used to 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.

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 at least one end of the flexible pipe. An end fitting provides a mechanical device which forms the transition between the flexible pipe body and a connector. The different pipe layers as shown, for example, in Figure 1 are terminated in the end fitting in such a way as to transfer the load between the flexible pipe and the connector. 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 flexible 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 may be provided by a platform 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.

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.

Figure 3 helps illustrate how a respective end of a segment of flexible pipe body 100 can be terminated in an end fitting 300. The end fitting 300 includes a main end fitting body 310 which includes a flanged end 315 which acts as a connector for securing to another end fitting in a back-to-back relationship or to a rigid structure. A narrow neck 320 extends into a central flared out region 330. The end fitting 300 includes an end fitting body 310 which defines an internal bore 335 running along a length of the end fitting body. This bore has a diameter to match a corresponding bore of the flexible pipe body. The end fitting body is made from steel or some other such rigid material. The flanged end region 315 provides a connector at a first end of the end fitting body. The other end of the end fitting body defines an open mouth 340 into which an end of a segment of flexible pipe body is received. The flanged connector is a substantially disc-like flared region of the end fitting body. The connector can be connected directly to a matching connector or a further end fitting body of an adjacent segment of flexible pipe body. This can be done using bolts or some other form of securing mechanism. Alternatively the connector 315 may be connected to a floating or stationery structure such as a ship, platform or the like. Various layers of flexible pipe body are introduced to the end fitting assembly, cut to an appropriate length, and sealingly engaged with a particular portion of the end fitting. As illustrated in Figure 3 the end fitting 300 also includes a jacket 350 which is secured at a first end of the jacket to the central flanged region of the end fitting body. The jacket has a substantially cylindrical outer surface. A remaining end of the jacket 350 is secured to an end plate 355. A radially inner surface 360 of the jacket remains spaced apart from a radially outer surface 365 of the open mouth end of the end fitting body 310 and a radially outer surface 370 of an inner collar 375. An outer sleeve 380 helps urge an outer sheath 170 against an outer seal 385. The spaced apart relationship of the inner surface 360 of the jacket and radially outer surfaces of the end fitting body and inner collar define a pocket region 390 or cavity void into which tensile armour wires 395 of the first tensile armour layer 140 and second tensile armour layer 150 are terminated. As part of a terminating process the cavity void in the pocket region 390 is filled with a curable material subsequent to the jacket being secured to the end fitting body. The curable material, such as epoxy resin, or the like solidifies to inter the individual tensile armour wires 395 in the pocket region. As illustrated in Figure 3 securing housings 398 are secured to end regions of the tensile armour wires at a predetermined distance from a tip of each wire to help anchor the tensile armour wires in the curable material. This helps increase resistance to the tensile armour wires being pulled through the epoxy material. This increases an extraction force needed to extract the wires.

Figure 4 helps illustrate an end region 400 of a particular tensile armour wire 395 in more detail. The tensile armour wire 395 shown in Figure 4 has a generally rectangular cross section with substantially parallel spaced apart long edges spaced apart by shorter edges. The shorter edges illustrated in the tensile armour wire shown in Figure 4 are slightly curved whereas the longer edges define substantially flat upper and lower surfaces for the tensile armour wires. It will be appreciated that certain embodiments of the present invention are broadly applicable to tensile armour wires and their anchoring having a wide selection of possible cross sections. Multiple helically wound tensile armour wires make up the inner and outer tensile armour layers of the flexible pipe body.

Figure 4 helps illustrate a free end 450 of a respective tensile armour wire and how this can be urged through a securing housing 460 in a threading motion. Thereafter the securing element body 460 can be slid along the outer surface of a tensile armour wire until it reaches a predetermined distance from the wire tip 450. Aptly this is 5cm. Aptly this is between 5 and 25cm. Aptly this is between 4 and 15cm from the wire end. As shown in Figure 4A the free end 450 is originally urged through an inlet opening 455 in the rigid housing 460. The inlet opening 455 is at a first end of the rigid housing. An outlet opening 470 is at a remaining end of the rigid housing and is spaced apart from the inlet opening 465. In this way when a free end 450 is threaded into the housing through the opening it enters a chamber region 475 and then can be continued to be threaded through the housing until the free end reappears exiting the chamber region via the outlet opening. The rigid housing holds a captive element which in the form shown in Figure 4 is a roller 480 which has a cylindrical outer surface 482. The captive element is located in a rigid housing prior to the tensile armour wire being threaded into the housing and once in the housing and once a tensile armour wire is threaded through the housing the roller cannot exit the housing because the opposed ends of the rigid housing are closed to some extent. For example, as shown in Figure 4A an inlet end of the housing (shown on the left hand side of Figure 4A) provides a relatively narrow inlet opening 465. The outlet end of the housing has a turned down part in the housing so that the height of the inlet opening and the height of the outlet opening are less than a thickness of a tensile armour wire and a diameter of the captive element.

As shown in Figure 4B in more detail an inner surface 485 of the housing includes a recess 490 which provides a seat for the roller 480 when it is moved towards the inlet opening.

Figure 4A thus illustrates how, in a mounting mode of operation, the roller 480 is located in the chamber region and then a tensile armour wire is threaded through the chamber region. This moves the roller towards the exit end of the housing (towards the right hand side of Figure 4A). In this mode of operation the roller does not hinder location of the rigid housing on an end of a tensile armour wire. Subsequently, and as illustrated in Figure 4C, when the housing is at a desired distance from the free end the housing can be pulled towards that free end. This causes movement of the roller element as a captive element towards the inlet opening 465 in the rigid housing. The roller slides against the inner abutment surface 485 until the roller becomes seated in the recess 490. Urging of the tensile armour wire during a termination process thereafter ceases and the roller remains in place without risk of rolling free. The chamber region thus includes a tapered zone (shown in the left hand side of Figure 4) which narrows towards an inlet opening. This tapered zone receives the captive element when it is moved towards the inlet opening until the captive element is driven into a squeezed position between an inner surface 485 of the rigid housing and an outwardly facing surface of a tensile armour wire. This helps prevent subsequent movement of the housing with respect to the tensile armour wire in a direction towards the free end of the tensile armour wire.

The rigid housing includes a first wall region shown as the upper wall part in Figure 4 which provides an inner abutment surface of the housing that at least partially defines the chamber region 475. The rigid housing also includes a further wall region (shown at the bottom of Figure 4 as a base) which thus acts as a base in use and that provides a further inner wall abutment surface region. At a tapered end either the upper wall or the lower wall or both the lower and upper wall are inclined to provide the tapered region. A narrowed end of the tapered zone narrows to a predetermined width at an end of the tapered zone proximate to the inlet opening. The predetermined width corresponds to a thickness dimension of a tensile armour wire plus an associated width dimension of the captive element minus a contraction distance of between 0.02 and 1 .00mm.

The inlet opening 465 shown in Figure 4 is provided as a through slot. It will be appreciated that other shaped openings can be envisaged according to other embodiments of the present invention so long as a tensile armour layer can be thrust through the opening and so that the captive element cannot be pulled through the inlet opening when a tensile armour wire tends to move outwards from the chamber region in a direction towards the inlet.

In use due to the mass and thus weight of the flexible pipe, tensile armour wires can tend to pull out of an end fitting with significant force. To be able to resist such force the captive element and the rigid housing must be sufficiently hard and rigid so as to be able to sustain continued load throughout the lifetime of a flexible pipe. Aptly a hardness of the rigid housing and/or a hardness of a captive element has a hardness greater than 12HRc. Aptly the hardness is greater than 30HRc. Aptly the hardness is greater than 40HRc.

Whilst the rolling element described with respect to Figure 4B has been described as a roller body it will be appreciated that an alternative embodiment of the present invention can utilise one or more spherical balls as rolling elements which roll along suitable channels within the rigid housing. The captive element can optionally include dimples and/or protrusions and/or knurling about its outer surface. The rigid housing is securable to a free end region of a tensile wire close to the free end of a tensile armour wire so strongly that wire breaks under tensile loading before the housing fails or pulls from the wire. Figure 5 illustrates how a rigid housing 460 can be secured at an end of an tensile armour wire in more detail. It will be appreciated that the external surfaces and particularly the end surfaces of the rigid housing close to the inlet opening provide anchoring points when the tensile armour wires are sealed/entombed in epoxy in a space within the end fitting. The surfaces thus provide a greater surface area than the tensile armour wire would otherwise provide alone which resists any movement of the housing once entombed in the hard epoxy. It will be appreciated that Figures 4 and 5 do not show side walls of the housing for the sake of clarity but that in practice the rigid housing could have rigid sides together with the upper and base parts which together form the chamber region and which confine the captive element during a termination process. Only six tensile armour wires are illustrated in Figure 5 for the sake of clarity. The skilled person will understand many more than six wires can be used to provide a tensile layer.

The rigid housing 460 can thus be used to enable an end region of at least one flexible pipe body tensile armour wire to be secured to an anchoring element. A rigid housing behaves as an anchoring element as it provides surfaces which act as an anchor to resist motion of the entire housing through hardened epoxy when a tensile armour wire tends to pull from an end fitting. The method of securing an end region of the wire to the anchoring element includes an operator first securing a rigid housing on an end of each tensile armour wire of flexible pipe body which is to be terminated in an end fitting. Each tensile armour wire free end is urged into a respective rigid housing that itself provides one or more anchoring surfaces. More than one rigid housing could of course be used on each wire to increase an anchoring strength. As the tensile armour wire is urged into the housing through an inlet opening a captive element is moved in a chamber region within the housing away from the inlet opening. Once at a desired position at an end region of the tensile armour wire, via respective movement of the rigid housing with respect to the tensile armour wire, the captive element is moved towards the inlet opening thereby driving the captive element into a generally tapered zone of the chamber region. This driving action continues until subsequent movement of the housing with respect to the tensile armour wire in a direction towards a free end of the tensile armour wire is prevented. This driving motion can be achieved via a human operator holding the housing threading it onto a tensile armour wire and then pulling the housing back towards the free end until the roller“locks” into the recess 490. Once the tensile armour wires each have a rigid housing mounted on them a desired distance from a free end of the wire. The end fitting termination process can continue using conventional techniques.

Figure 6A illustrates an alternative embodiment of the present invention in which a rigid housing 660 formed from a hard material has an inlet opening 665 formed as a through slot. At an opposed end of the housing 660, an exit opening 670 is provided in a spaced apart relationship. The housing 660 includes a base and an upper portion and spaced apart side walls and end walls which include the through openings. The walls’ inner surfaces define a central chamber region 675. A captive element 680 is located within the central chamber region 675. The captive element 680 illustrated in Figure 6 is a roller which has a substantially cylindrical outer surface and is an elongate hard integrally formed body having generally circular ends. The roller can thus roll on a upper surface of a tensile armour wire threaded through the housing. Instead of the recess 490 illustrated with respect to the embodiment shown in Figure 4 and 5 the upper wall of the rigid housing 660 shown in Figure 6 has an elongate through cut which forms a space 690. In this way when a free end 450 is urged through the housing 660 in the direction of the arrow shown in Figure 6A the captive element is moved away from the inlet opening where it can move freely in the chamber region. The captive element is prevented from moving out of the exit end of the housing by virtue of a downturned portion of the end wall such that the opening at the exit end of the housing has a smaller dimension that the tensile armour wire plus the diameter of the rolling roller. Once at a predetermined distance from the free end 450 the rigid housing can be moved in the direction shown in the arrow in Figure 6B. This causes the roller to be driven towards the inlet opening where the roller is driven into a tapered zone. The elongate opening 690 provides a seat for the roller to sit in once it is driven into the tapered region. At this point the roller element is forced into a tapered arrangement between an outer surface of the tensile armour wire and the abutment surface of the rigid housing effectively locking the tensile armour wire in the housing.

Figure 7 illustrates an alternative embodiment of the present invention in which a rigid housing 760 formed from a hard material has an inlet opening 765 formed as a through slot. At an opposed end of the housing, an exit opening 770 is provided in a spaced apart relationship with respect to the inlet end of the housing. The housing 760 includes a base and an upper portion and spaced apart side walls and end walls in which through openings are provided. The walls’ inner surfaces define a central chamber 775. A captive element 780 is located within the central chamber region 775. The captive element 780 illustrated in Figure 7 is a roller which has a substantially cylindrical outer surface and is an elongate hard integrally formed body having generally circular ends. The roller can thus roll on an upper surface of a tensile armour wire threaded through the housing. Instead of the recess 490 illustrated with respect to the embodiments shown in Figures 4 and 5 or the cut described with respect to the embodiment shown in Figure 6 the rigid housing 760 shown in Figure 7 has a stamped out tongue 785. This tongue 785 can be formed by providing a C-shaped cut 787 which is illustrated best in Figure 7C. The tongue 785 is integrally formed with the remainder of the material of the rigid housing upper surface and can to some extent bend around a flexible region 789. In this way when a free end 450 of a tensile wire is urged through the housing 760 in the direction of the arrow shown in Figure 7A the captive element is moved away from the inlet opening where it can move freely in the chamber region. The captive element is prevented from moving out of the exit of the housing by virtue of an end wall of the housing such that the opening at the exit end of the housing has a smaller dimension that the tensile armour wire plus the diameter of the rolling roller. Once at a predetermined distance from the free end 450 the rigid housing can be moved in the direction shown by the arrow in Figures 7B and 7C. This causes the roller to be driven towards the inlet opening where the roller is driven into a tapered zone. The tapering causes a narrowing which causes the roller 780 to be driven against the tensile armour wire. Once the roller passes the location of the end of the C-shaped cut 787 the material of the tongue springs downwards. This prevents backward motion of the roller so that at this point the roller element is forced into a tapered arrangement between an outer surface of the tensile armour wire and the abutment surface of the rigid housing and effectively locked in place thus locking the tensile armour wire in the housing.

Figure 8 illustrates an alternative embodiment of the present invention in which a rigid housing 880 formed from a hard material has an inlet opening 865 formed as a through slot. At an opposed end of the housing 860, an exit opening 870 is provided in a spaced apart relationship with the inlet opening. The housing 860 includes a base and an upper portion and spaced apart side walls and end walls which include the through openings. The walls’ inner surfaces define a central chamber region 875. An inwardly facing surface of the upper part of the housing is roughened by including knurling. Other roughening techniques such as creation of a crosshatched groove arrangement can be used to provide the roughened surface 878. A captive element 880 is located within the central chamber region 875. An outer surface 895 of the captive element is likewise roughened. In the embodiment shown in Figure 8 the roughened outer surface 895 is knurled. It will be appreciated that other techniques for roughening the outer surface of the roller or rolling ball could be utilised. Motion of the tensile armour wire and captive element occurs in many ways similar to the previously described embodiments but the locking in place technique is provided by the opposed roughened surfaces of the outer surfaces of the rolling element and the roughened surface of the upper wall of the rigid housing.

According to certain embodiments described hereinabove a method of terminating flexible pipe body in an end fitting can be achieved by providing an end fitting body including a connecting flange at a first end and an open mouth at a further end, threading an end of one or more tensile armour wires of a segment of flexible pipe body through respective securing element bodies (thereby simultaneously moving a captive element in a housing to thereby resist subsequent withdrawal of the tensile armour wire from the securing element body), securing a jacket member to the end fitting body thereby providing a pocket region within the end fitting where the tensile armour wire ends are located and subsequently providing a curable material in the pocket region. Aptly the curable material is an epoxy resin and this can subsequently be cured to inter the armour wire ends in epoxy material. The rigid housing bodies affixed to the wires are difficult to pull through the epoxy and difficult to remove from the wires.

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.

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.

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

Claims

CLAIMS:

1 . Apparatus for securing an end region of a tensile armour wire within a flexible pipe end fitting, comprising:

2. The apparatus as claimed in claim 1 , further comprising:

the rigid housing comprises a first wall region that provides a first inner abutment surface of the housing that at least partially defines the chamber region; a further wall region that provides a further inner wall abutment surface region that is inclined with respect to the first inner abutment surface region to define a tapered zone therebetween.

3. The apparatus as claimed in claim 2, further comprising:

the narrow end of the tapered zone narrows to a predetermined width at an end of the tapered zone proximate to said inlet opening, said predetermined width corresponding to a thickness dimension of a tensile armour wire plus an associated width dimension of the captive element minus a contraction distance of between 0.02 and 1 .00 mm.

4. The apparatus as claimed in claim 2 or claim 3 wherein the narrow end of the tapered zone has a width of between 7 and 18 mm.

5. The apparatus as claimed in any preceding claim wherein the inlet opening is a through slot in an end of the rigid housing.

6. The apparatus as claimed in any one of claims 1 to 5, further comprising:

the rigid housing further comprises an outlet opening in the housing through which a free end of the tensile armour wire can be urged to thereby thread the rigid housing over a free end region of the tensile armour wire.

7. The apparatus as claimed in claim 6, further comprising:

the rigid housing comprises a material that has a hardness greater than 12

HRc.

8. The apparatus as claimed in claim 7 wherein the hardness is greater than 30 HRc and is optionally greater than 40 HRc.

9. The apparatus as claimed in any preceding claim, further comprising:

the captive element is at least one spherical ball or a roller body having a substantially cylindrical outer surface.

10. The apparatus as claimed in any claim 9, further comprising:

the captive element further comprises dimples, protrusions or knurling around its outer surface.

1 1 . The apparatus as claimed in claim 9 or 10, further comprising:

the captive element comprises a material that has a hardness greater than 12

HRc.

12. The apparatus as claimed in claim 1 1 wherein the hardness is greater than 30 HRc and optionally is greater than 40 HRc.

13. The apparatus as claimed in claim 9 or 10 wherein the captive element comprises a metallic material or a ceramic material.

14. The apparatus as claimed in any preceding claim wherein the rigid housing is securable to the free end region so strongly that wire breaks under tensile loading before the housing pulls from the wire.

15. A method of securing an end region of at least one flexible pipe body tensile armour wire to an anchoring element, comprising the steps of:

16. The method as claimed in claim 15, further comprising:

urging the free end region by threading a free end of a tensile armour wire through the inlet opening in a first end of the rigid housing and through an outlet opening in a remaining end of the rigid housing whereby the housing and associated anchoring surface slides along the free end region of the tensile armour wire to a desired location a predetermined distance from the free end.

17. A method of terminating flexible pipe body in an end fitting, comprising the steps of:

subsequently moving the captive element towards said inlet opening via movement of the rigid housing towards the free end of the tensile armour wire thereby driving the captive element into a tapered zone of the chamber region until subsequent withdrawal of the tensile armour wire from the rigid housing is prevented; securing a jacket member to the end fitting body thereby providing a cavity void region in the end fitting where respective end regions of the plurality of tensile armour wires and associated rigid housings and respective anchoring surfaces are located; and subsequently providing a curable material in the cavity void region.

18. The method as claimed in claim 17, comprising:

moving the captive element towards said inlet opening by subsequently urging the tensile armour wire in a reverse direction with respect to the housing to thereby move the captive element towards said inlet opening thereby locating the captive element at a narrow end of a generally tapered zone of the chamber region where the captive element is prevented from moving further towards the inlet opening and is urged against the armour wire as the armour wire is pulled out from the inlet opening thereby preventing motion of the wire away from the housing.

19. The method as claimed in claim 18, further comprising:

applying a load to the tensile armour wire of at least 50% of the structural capacity of the tensile armour wire to thereby confirm that the rigid housing and associated anchoring surface is secured at a desired location.

20. The method as claimed in claim 17, 18 or 19, further comprising:

subsequently curing the material and thereby anchoring the tensile armour wire end regions in the cured material in the pocket region via the rigid housings on each tensile armour wire end region.