EP3237721A1

EP3237721A1 - Modular tubing rack assembly

Info

Publication number: EP3237721A1
Application number: EP15741253.7A
Authority: EP
Inventors: Steven Brown
Original assignee: Swire Oilfield Services Ltd
Current assignee: Swire Energy Services Ltd
Priority date: 2014-12-23
Filing date: 2015-06-30
Publication date: 2017-11-01
Also published as: WO2016102910A1; GB2535137B; GB2535137A

Abstract

A modular tubing rack assembly comprising a walkway section comprising a walkway platform, a first support tower and at least one further support tower defining a safe working area for an operator, the towers being spaced apart in a direction along a length of the platform so that a walkway is defined, and at least one tubing support section comprising a tubing support platform for receiving tubular members laid down on their sides, the tubing support section being releasably securable to the walkway section and having a length which is at least equal to a spacing between the support towers of the walkway section. The support towers being adapted to support tubular members positioned laterally of the towers on the tubing support section platform, to prevent the tubular members from encroaching into the walkway.

Description

MODULAR TUBING RACK ASSEMBLY

The present invention relates to a tubing rack assembly. In particular, but not exclusively, the present invention relates to a tubing rack assembly for supporting and restraining a plurality of elongate tubular members on a deck of a vessel, the assembly comprising a support tower defining a safe working area for an operator and adapted to support tubular members positioned laterally of the tower. In the oil and gas exploration and production industry, various different types of elongate tubular members are required in order to gain access to subsurface oil and gas deposits. For example, in order to access a rock formation containing well fluids (oil and/or gas), it is necessary to drill a wellbore from surface employing a drill string comprising a large number of lengths of metal tubing, which are coupled together end-to end, and which carries a drill bit at a lower end. Following drilling, it is necessary to line the wellbore with metal wellbore-lining tubing known as casing, and which again comprises lengths of tubing coupled together end to end. Once the well has been completed, by installation of the casing, well fluids can be recovered to surface through production tubing, which once again comprises lengths of metal tubing coupled together end to end.

When a well is to be formed in an offshore location, this presents a number of challenges, not least of which is that all of the equipment required to drill and complete the well, and to recover well fluids to surface, has to be transported offshore and stored. Consequently, all of the different types of tubular members which are required have to be transported offshore on a service vessel, and then transferred from the vessel to an offshore drilling/production facility, using suitable lifting equipment. The tubular members are relatively long (typically around 30' to 40' or ~ 9.14m to ~12.19m) and heavy, particularly in the case of wellbore casing. The tubular members have to be stored in a laid-down orientation, i.e. on their sides, so as to not to impact on vessel stability. The tubular members are typically stacked on their sides on a deck of the vessel, so that they can be easily accessed. Frequently in excess of 100 such tubular members may be stacked on the vessel deck.

The tubular members have to be restrained so as to prevent them from moving around on the vessel deck, particularly under external wind, wave and tidal loads. In the past, this was achieved using 'Sampson posts', which locate in access points that are recessed into the vessel deck. The Sampson posts were used to create an area of deck space specifically for the tubular members, the tubular members being stacked between a line of Sampson posts and a wall at an edge of the vessel deck. Problems with Sampson posts include that the height to which the tubular members can be stacked is limited by the height of the posts. The posts have to be small and light enough for manual handling by a vessel operative, which restricts their length and thus the height to which tubulars can be stacked. There are also concerns within the industry about the strength of the posts, particularly in heavy sea-state conditions. The posts are also difficult for crane operators to see, and so present challenges when lowering bundles of tubular members into position. Finally, there is no defined termination point for transit slings which extend around bundles of tubular members, and which are used to raise and lower the bundles. As a result, vessel deck operators may be tempted to walk on top of the stacked tubular members, which can be extremely hazardous.

To this end, tubing rack assemblies have been developed which seek to address these problems. One prior tubing rack assembly is a generally inverted T-shaped assembly, comprising a central support tower which defines a safe working area for an operator, and two sets of legs which extend out from the tower and rest on the vessel deck. The tubular members are located on the sets of legs. The tower comprises upright supports which support tubular members positioned laterally of the tower, to prevent them from encroaching into the working area.

Typically two such tubing rack assemblies are provided, and are positioned spaced apart along the vessel deck, so that the towers of the two rack assemblies define a walkway between bundles of tubulars stored either side of the towers. This is problematic because it requires the tubing rack assemblies to be carefully positioned on the deck of the vessel, and individually anchored to the vessel deck. This is a time- consuming procedure. In addition, a bundle of tubular members must be supported on one side by the support members of the tower, and on the other by a wall at the edge of the vessel deck. As a result, the legs of the tubing rack

assemblies are required to span across the entire width of the deck. This requires adjustment of the lengths of the legs, by adding or removing individual leg extension pieces, and indeed careful positioning of the tower. Once again this is a time-consuming procedure.

Furthermore, tubular members positioned on the legs of such spaced tubing rack assemblies are only supported at two spaced locations, which will typically be towards their ends. The tubular members are unsupported along large parts of their lengths, which can cause them to become bowed at a location between the supports, potentially suffering permanent plastic deformation (particularly under the load of further tubular members stacked above those resting on the legs). This is very undesirable bearing in mind that the tubular members are to be subsequently deployed into a long wellbore of relatively small diameter.

The present inventor has appreciated the shortcomings of the foregoing disadvantages.

According to a first aspect of the present invention, there is provided a modular tubing rack assembly for supporting and restraining a plurality of elongate tubular members on a deck of a vessel, the assembly

comprising:

a walkway section comprising a walkway platform, a first support tower and at least one further support tower, each support tower defining a safe working area for an operator, the first support tower and the at least one further support tower being spaced apart in a direction along a length of the platform so that a walkway is defined which extends along the walkway platform from the working area defined by the first support tower to the working area defined by said further support tower; and

at least one tubing support section comprising a tubing support platform for receiving tubular members laid down on their sides, the tubing support section being positionable to one side of the walkway section and releasably securable to the walkway section, to thereby form the tubing rack assembly;

in which the tubing support section platform has a length which is at least equal to a spacing between the support towers of the walkway section, and is arranged so that it spans from the first support tower to said further support tower when the tubing support section is secured to the walkway section;

and in which the support towers are adapted to support tubular members positioned laterally of the towers on the tubing support section platform, to prevent the tubular members from encroaching into the walkway.

Advantageously, the first and at least one further support tower of the walkway section are spaced apart a distance which is less than a length of a tubular member which is to be positioned on the platform of the tubing support section. As the tubing support section platform spans from the first tower to the at least one further tower, this has the effect of preventing the tubular members from encroaching into the walkway. In particular, in the event that any tubular members on the platform shifted during use (for example under external loading on a vessel carrying the modular tubing rack assembly), the tubular members could not encroach into the walkway. A safe path is thus provided for an operator to walk along the platform of the walkway section, to gain access to tubular members stored on the tubing support section.

In particular, a plurality of bundles of tubular members may be stored on the tubing support section platform, each bundle comprising a plurality of tubular members. The tubular members in each bundle may be grouped together using a sling or slings which extend around the tubular members, and which are used to raise and lower the bundles (the sling(s) being coupled to a crane hook or other lifting gear). Provision of the safe walkway for an operator facilitates access to the slings without exposing the operator to risks due to the bundles shifting under external loading. Accordingly, there is no need for the operator to climb on top of the bundles of tubular members, to gain access to slings.

Provision of a modular tubing rack assembly, comprising the walkway section and at least one such tubing support section also provides advantages over prior tubing rack assemblies. In particular, the walkway section can be quickly and easily positioned on a vessel of a deck and locked in position (using suitable locking members), and the tubing support section positioned to a desired side of the walkway section and releasably secured to the walkway section, to form the completed tubing rack assembly. In contrast to prior tubing rack assemblies, there is no requirement to position and separately lock individual towers to the vessel deck.

Furthermore, the provision of a tubing support section having a platform which spans from the first support tower to the at least one further support tower provides improved support for tubular members stored on the tubing section platform, when compared to prior tubing rack assemblies. In particular, a length of the tubing support section platform may be selected so that the tubular members which are to be stored on the platform are supported over a substantial part of their length, a majority of their length, or their entire length. This avoids the deformation problems which occurred with prior tubing rack assemblies.

Reference is made herein to a modular tubing rack assembly for supporting and restraining a plurality of elongate tubular members on a deck of a vessel. Whilst reference is made specifically to the deck of a vessel, it will be understood that the modular tubing rack assembly can be provided on the deck of any other suitable offshore facility, which may be a floating or fixed facility, and which may be a drilling rig, production rig, a floating production, storage and offloading vessel (FPSO) and/or a floating storage and offloading vessel (FSO).

The tubing support section may be a first tubing support section, and the tubing rack assembly may comprise at least one further tubing support section. The at least one further tubing support section may be releasably securable to at least one of the walkway section, and to another tubing support section (in particular, the first tubing support section). Optionally, a further tubing support section is positionable to a side of the walkway section which is opposite to the side of the walkway section where the first tubing support section is positioned.

The provision of at least one such further tubing support section provides a greater degree of adjustability in the shape and/or dimensions of the tubing rack assembly, so that it can be suited to vessel decks of a wide range of different dimensions. Additionally or alternatively, the provision of a plurality of such tubing support sections may provide the option of positioning tubular members to one or both sides of the walkway section.

The at least one tubing support section may have a width, defining a width of the platform. At least one tubing support section may have a width which is different from a width of at least one other tubing support section. This may provide a greater ability to adjust a width of the assembly, for example to provide an assembly of a desired width and/or to suit a particular vessel deck.

The support towers of the walkway section may be positioned on/may extend from the walkway platform. The support towers may be provided integrally with the walkway section platform. In this way, the support towers and platform can be transported, positioned and coupled to the tubing support section as a unit. This also has the advantage of maintaining a fixed spacing between the towers.

The walkway section may comprise the first support tower, and the at least one further support tower may be a second support tower. The first support tower may be provided at, near or adjacent a first end of the walkway section platform. The second support tower may be provided at, near or adjacent a second end of the walkway section platform which is opposite to the first end. The walkway section may comprise at least one intermediate support tower disposed between the first and second support towers and defining a safe working area. The intermediate support tower may be positioned so that the walkway which is defined extends along the walkway platform from the working area defined by the first support tower, through the working area defined by the at least one intermediate support tower and to the working area defined by the second support tower.

The spacing between the first support tower and the at least one further support tower may be defined between adjacent or facing parts of the towers. The at least one tubing support section may span from the first support tower to the at least one further support tower in that it may bridge the spacing between the towers.

The support towers may each be defined by a support tower structure. The structure may define a perimeter of the working area. The structure may extend to a height above a surface of the walkway platform. The height may be selected to be greater than the average height of an operator (typically at least 2m, and optionally up to around 2.5m), to provide protection for the operator, for example, during the lowering of bundles of tubular members into position on the tubing section platform. A height dimension of the support towers may be greater than at least one of a width and a length of the towers.

The support towers may be adapted to support tubular members on both sides of the towers (on tubing support section platforms), and thus the walkway section. Each support tower may have at least one upright support for supporting tubular members positioned laterally of the tower on the tubing support section platform, to prevent the tubular members from encroaching into the walkway.

The at least one upright support of each support tower may be a column, post or the like forming part of the tower. The support tower structure may comprise or take the form of a frame. The upright support may be a member of the frame. The upright support may be substantially vertically oriented so that, in use, the support extends substantially perpendicularly to the deck of the vessel and/or to the walkway section platform.

The support towers may comprise a plurality of upright supports. The support towers may comprise at least one upright support on or at a first side of the tower, and at least one further upright support on or at a second side of the tower which is opposite the first side. In this way, tubular members can be supported (on tubing support section platforms) on both sides of the towers, and thus the walkway section. The support towers may comprise at least one upper cross-member, which may define an upper extent of the safe working area. The cross- members) may serve for preventing tubular members from being lowered into the safe working area, thus providing protection for an operator located within the working area from coming to harm.

Each support tower may comprise a sling retainer for retaining at least one sling, the sling extending, in use, around at least one tubular member positioned on the tubing support section. The sling retainer may be a post, rod, column, hook, clip or the like coupled to or forming part of the support tower. The sling retainer may be accessible by a user from within the safe working area of the respective support tower. Advantageously therefore, an operator can access the sling or slings from a position where he or she is safe from harm, for example, due to the tubular member shifting under external loading. This facilitates safe access to the sling or slings for securing them to a crane hook for lifting the tubular member(s).

The assembly may comprise at least one securing arrangement for releasably securing the tubing support section to the walkway section. The securing arrangement may be a quick release securing arrangement. The securing arrangement may comprise a first securing component provided on the tubing support section and a second securing component provided on the walkway section, the first securing component mating with the second securing component to secure the tubing support section to the walkway section. One of the first and second securing components may be a male component and the other one of the first and second securing components may be a female component. The securing arrangement may comprise a locking element such as a pin, bolt or the like for locking the first securing component to the second securing component. Where the assembly comprises at least one further tubing support section, a similar such securing arrangement may be provided for releasably securing the further tubing support section to one or both of the walkway section and another tubing support section. A first securing component provided on one of the tubing support sections may then mate with a second securing component provided on the other tubing support section.

The walkway section and the at least one tubing support section may each have a length, width and height which facilitates transportation of the sections on a standard flatbed vehicle trailer. Typical trailer lengths and widths, and the maximum height of loads which can be carried on such trailers, vary from country to country. However, the walkway section and tubing support section may have a length which is no greater than 12 metres; a width which is no greater than 2.55 metres; and a height which is no greater than 2.896 metres. Typically the sections are transportable in a stacked arrangement, with the walkway section stacked on top of the at least one tubing support section.

The walkway platform and the tubing support platform of the at least one tubing support section may be substantially planar and elongate. In the case of the tubing support section, this may serve for supporting tubular members along all of, substantially all of, or a majority of, their length. The tubing support section, in particular its platform, may be at least around 30' (~ 9.14m) in length, and may be up to around 40' (~12.19m) in length. According to a second aspect of the present invention, there is provided a modular tubing rack system comprising:

a first modular tubing rack assembly according to the first aspect of the invention; and

a second modular tubing rack assembly according to the first aspect of the invention;

in which the first and second modular tubing rack assemblies can each be arranged to define first tubing storage areas between the support towers of their walkway sections and a part of the vessel, and second tubing storage areas between the support towers of their walkway sections and the support towers of another modular tubing rack assembly.

The first and second modular tubing rack assemblies may each be arranged to define first tubing storage areas between the support towers of their walkway sections and a wall of the vessel. The wall may be a wall which extends at least part way around the vessel deck. The system may comprise a third modular tubing rack assembly according to the first aspect of the invention, the third assembly adapted to be positioned between the first and second modular tubing rack assemblies. The third modular tubing rack assembly may be arranged to define: a first tubing storage area between the support towers of its walkway section and the support towers of the first modular tubing rack assembly; and a second tubing storage area between the support towers of its walkway section and the support towers of the second modular tubing rack assembly.

Further features of the modular tubing rack assemblies of the second aspect of the invention may be derived from the text set out above relating to the first aspect of the invention. According to a third aspect of the present invention, there is provided a method of supporting and restraining a plurality of elongate tubular members on a deck of a vessel, the method comprising the steps of:

positioning a walkway section on the vessel deck, the walkway section comprising a walkway platform, a first support tower and at least one further support tower, each support tower defining a safe working area for an operator, the first support tower and the at least one further support tower being spaced apart in a direction along a length of the platform so that a walkway is defined which extends along the walkway platform from the working area defined by the first support tower to the working area defined by said further support tower;

positioning at least one tubing support section on the vessel deck to one side of the walkway section;

arranging a platform of the tubing support section so that it spans from the first support tower to said further support tower; releasably securing said tubing support section to the walkway section; and

laying a plurality of tubular members down on their sides on the platform of the tubing support section;

in which the walkway section towers support the tubular members to prevent the tubular members from encroaching into the walkway.

Further features of the method of the third aspect of the invention may be derived from the text set out above relating to the first and/or second aspect of the invention.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a modular tubing rack assembly for supporting and restraining a plurality of elongate tubular members on a deck of a vessel, in accordance with an embodiment of the present invention;

Figs. 2 and 3 are side and plan views, respectively, of the tubing rack assembly shown in Fig. 1 ;

Figs. 4 and 5 are perspective views of a walkway section and a tubing support section, respectively, forming part of the tubing rack assembly of Fig. 1 , both of which are taken from different angles to Fig. 1 ;

Fig. 6 is a perspective view showing the tubing rack assembly of Fig. 1 during assembly on a deck of a vessel; Fig. 7 is a view similar to Fig. 6, but taken from a different angle; Fig. 8 is a further enlarged view of the tubing rack assembly shown in Fig. 7, illustrating a securing arrangement of the assembly; Fig. 9 is a perspective view of a modular tubing rack system comprising first and second modular tubing rack assemblies, of the type shown in Fig. 1 , spaced out along a length of a vessel deck; and

Fig. 10 is a perspective view of a modular tubing rack system comprising first and second modular tubing rack assemblies, of the type shown in Fig. 1 , cooperating so that additional tubular members can be stored in a space between the tubing rack assemblies.

Turning firstly to Fig. 1 , there is shown a perspective view of a modular tubing rack assembly for supporting and restraining a plurality of elongate tubular members on a deck of a vessel, the tubing rack assembly indicated generally by reference numeral 10. The tubing rack assembly 10 is also shown in the side and plan views of Figs. 2 and 3, respectively. The tubing rack assembly 10 comprises a walkway section, indicated generally by reference numeral 12, and at least one tubing support section, indicated generally by reference numeral 14. The walkway section 12 is shown in isolation in the perspective view of Fig. 4, whilst the tubing support section is shown in isolation in the perspective view of Fig. 5, both of which are taken from different angles to Fig. 1 .

The walkway section 12 comprises a walkway platform 16, a first support tower 18, and at least one further support tower which, in the illustrated embodiment, is a second support tower 20. Each support tower 18 and 20 defines a safe working area for an operator, indicated by the numerals 22 and 24, respectively.

The first and second support towers 18 and 20 are spaced apart in a direction along a length of the platform 16 so that a walkway 26 is defined which extends along the walkway platform 16 from the working area 22 defined by the first support tower 18 to the working area 24 defined by the second support tower 20. The towers 18 and 20 are each provided integrally with the platform 16, so that the entire walkway section 12 can be transported and moved into position as a unit.

The tubing support section 14 comprises a tubing support platform 28 for receiving tubular members laid down on their sides, three such tubular members 31 being shown in the plan view of Fig. 3, stacked in a bundle. It will be understood that the tubular members may be any one of the various different types of tubular members which are employed in the oil and gas exploration and production industry, including but not restricted to: lengths of wellbore casing or liner; drill tubing including drill collars;

production tubing; and tubing which is to form part of a tool string to be run downhole.

The tubing support section 14 is positionable to one side 30 of the walkway section 12, and is releasably securable to the walkway section 12, to thereby form the tubing rack assembly 10. The tubing support platform 28 has a length which is at least equal to a spacing 32 (Fig. 2) between the support towers 18 and 20 of the walkway section 12, in particular between adjacent parts 33 and 35 of the towers 18 and 20, respectively. As can clearly be seen from the drawings, the tubing support section 14 is arranged so that the platform 28 spans from the first support tower 18 to the second support tower 20, when the tubing support section 14 is secured to the walkway section 12. In this way, the platform 28 bridges the spacing (or gap) 32 between the first and second towers 18 and 20. The support towers 18 and 20 are each arranged to support tubular members 31 positioned laterally of the towers 18 and 20, on the tubing support section platform 28. In this way, the tubular members 31 are prevented from encroaching into the walkway 26 defined by the walkway section 12 (thus providing protection for an operator on the walkway from coming to harm). To this end, the support towers 18 and 20 comprise at least one upright support 34 and 36, respectively, which support the tubular members 31 .

The modular tubing rack assembly 10 will now be described in more detail, with reference also to Fig. 6, which is a perspective view showing it during assembly on a deck 38 of a vessel 40; Fig. 7 which is a view similar to Fig. 6 but taken from a different angle; and Fig. 8 which is a further enlarged view illustrating a securing arrangement 42 of the assembly. Optionally, the tubing rack assembly 10 can comprise further tubing support sections 14, to form an assembly of a desired width. Variation of a width of the assembly 10 may be desirable in order to accommodate a larger number of tubular members 30 to 34, and/or to account for variations in the dimensions (particularly width) of different vessel decks 38.

In the illustrated embodiment, the tubing rack assembly 10 comprises the tubing support section 14, which forms a first such section, and a further tubing support section 14'. The further tubing support section 14' forms a second such section, and is of like construction to the first tubing support section 14 (like components sharing the same reference numerals with the addition of the suffix ' ). The second tubing support section 14' is releasably securable to at least one of the walkway section 12 and the first tubing support section 14. The second tubing support section 14' is, however, shown secured to the first tubing support section 14, in particular to a side 44 of the first section. In a variation, the second tubing support section 14' may be positionable to a side 46 of the walkway section 12, which is opposite the side 30 where the first tubing support section 14 is positioned. Equally, a further tubing support section (not shown) may be provided and secured to the walkway section 12, optionally with yet further such tubing support sections secured to it (in a similar way to the sections 14 and 14').

Returning to the walkway section 12, the first and second support towers 18 and 20 are each defined by a support tower structure in the form of frames 48 and 50, respectively. The frames 48 and 50 define perimeters of the respective working areas 22 and 24, and extend to a height above a surface of the walkway platform 16, the height being selected so that it is greater than an average height of an operator. Typically the height will be at least 2 metres, optionally up to around 2.5 metres, and in particular may be around 2.2 to 2.3 metres. This provides protection for the operator, for example, during the lowering of bundles of tubular members 31 into position on the tubing section platforms 28, 28'. It will be understood that the support towers 18 and 20 are generally tower-like structures in that a height dimension of the towers is greater than at least one of a width and a length of the towers (typically both), and that they define structures within which the operator can stand, within the working areas 22 and 24.

The upright supports 34 and 36 of the towers 18 and 20 each take the form of a column of the support tower frame 48, 50, four such columns being provided in a generally rectangular pattern. The upright support columns 34 and 36 are substantially vertically oriented, and in particular are substantially perpendicular to the deck 38 of the vessel 40 and/or the walkway section platform 16. This provides maximum stability for tubular members 31 located on the tubing section platforms 28 and 28'. It will be understood however that the columns 34 and 36 need not necessarily be substantially vertically oriented, and in particular may be inclined from the vertical, optionally inclining outwardly and so effectively towards tubing support sections positioned to the side or sides 30, 46 of the walkway section 12. The support towers 18 and 20 also comprise upper cross- members in the form of snagging rails 52 and 54, which provide additional protection for an operator located within the safe working areas 22 and 24. In particular, the snagging rails 52 and 54 prevent tubular members 31 from being lowered into the safe working areas 22 and 24.

The support towers 18 and 20 also comprise sling retainers 56 and 58, respectively, and typically have one such sling retainer associated with each of the upright support columns 34 and 36. In the illustrated embodiment, the sling retainers 56 and 58 take the form of elongate rods, which extend up from a base 60 of the walkway section 12, and which have free ends 62 and 64, respectively over which slings for the tubular members (not shown) can be located. This is of particular use where a large number of bundles of tubular members 31 are positioned on the tubing support sections, 14 and 14'. In particular, they enable an operator to access the slings from the safe working areas 22 and 24, and to safely couple the slings to lifting equipment such as a crane hook (not shown), for raising a selected bundle of tubular members 31 .

Returning to the securing arrangement 42, the tubing rack assembly 10 includes a plurality of such securing arrangements for releasably securing the tubing support section 14 to the walkway section 12, and the second tubing support section 14' to the first tubing support section (or walkway section). Each securing arrangement 42 comprises a first securing component 66 and a second securing component 68, the first securing component 66 mating with the second securing component 68. In the case of the first tubing support section 14, this comprises a pair of first securing components 66, which mate with a respective pair of second securing components 68 on the walkway section 12. However, the first tubing support section 14 also comprises a pair of second securing components 68, first securing components 66 on the second tubing support section 14' mating with the second components 68 on the first tubing section 14.

The first securing components 66 each take the form of male components, in particular shaped prongs, whilst the second securing components 68 each take the form of female securing components, in particular pockets 68 which can receive not only the prongs 66, but also the forks of a fork-lift truck (not shown), which can be used to move the walkway section 12 and tubing support sections 14, 14' into position. The prongs 66 each include inclined side surfaces 70, which serve for centralising the prongs 66 within the pockets 68, and so for guiding the prongs 66 into mating engagement with the fork pockets 68. Following mating of the prongs 66 within the respective fork pockets 68, a locking element in the form of a locking pin 72 is used to lock the prongs 66 within the fork pockets 68. The locking pins 72 are inserted through apertures 74 in the prongs 66, and apertures 76 in the fork pockets 68, which align when the prongs 66 are fully mated with the pockets 68.

The walkway section 12 and the tubing support sections 14 and 14' each have a length, width and height which facilitates transportation of the sections on a standard flatbed vehicle trailer (not shown). Typical trailer lengths and widths, and the maximum height of loads which can be carried on such trailers, vary from country to country. However, the walkway section 12 and tubing support sections 14, 14' will typically have a length which is no greater than 12 metres, a width which is no greater than 2.55 metres, and a height which is no greater than 2.896 metres. The maximum height dimension is the maximum typical height of standard ISO containers. Typically, the sections 12, 14 and 14' are transportable in a stacked arrangement, with the walkway section 12 stacked on top of the tubing support sections 14, 14'. Typically the maximum stacked height will be no greater than that mentioned above.

A length of the tubing support section platforms 28 and 28' is selected so that it provides support for tubular members 31 along all of, substantially all, or a majority of their length. Typically, the tubular members 31 will have a length of around 30 feet (circa 9.14 metres) to around 40 feet (circa 12.19 metres), and the platforms 28 and 28' will be dimensioned

accordingly. The method of assembling the tubing rack assembly 10 will now be described, with reference also to Fig. 9, which shows a modular tubing rack system comprising two such modular tubing rack assemblies 10 and 10a, positioned on the deck 38 of the vessel 40. Like components of the modular tubing rack assembly 10a with the assembly 10 of Figs. 1 to 8 share the same reference numerals, with the addition of the suffix 'a'.

The walkway section 12 and tubing support sections 14, 14' of the modular tubing rack assembly 10 are transported to the vessel 40, typically on a vehicle trailer, where the vessel is docked in a port. The sections 12, 14 and 14' are each hoisted onto the vessel deck 38 using a crane and suitable slings 76, 78 and 80. The tubing support section 14' is positioned on the deck 38 adjacent a side wall 82 which extends around the deck 38, and which restrains the tubular members 31 on the side spaced from the walkway section 12.

The first tubing support section 14 is then positioned on the deck 38 adjacent to the second tubing support section 14', and the two are secured together by mating the prongs 66 on the second tubing support section 14' within the fork pockets 68 on the first tubing support section 14 (the sections being locked together using the pins 72). The walkway section 12 is then positioned on the vessel deck 38, and secured to the first tubing support section 14 in a similar fashion. Each of the walkway section 12, first tubing support section 14 and second tubing support section 14' are secured to the vessel deck 38. This is achieved by securing the sections 12, 14 and 14' to tie-down points on the vessel 40 (not shown), using chain binders (also not shown) which engage tie-down points 84, 86 and 86', respectively, on the sections 12, 14, 14'. Once assembled and secured to the vessel deck 38 in this way, bundles of tubular members 31 can be positioned on the tubing support section platforms 28 and 28'.

The walkway section 12 thus defines a safe walkway 26 along which an operator can pass, particularly to gain access to the slings which are used to raise and lower the bundles of tubular members 31 . Specifically, when a bundle of tubular members 31 is lowered onto one of the platforms 28 or 28' (or indeed on top of previously stacked bundles), an operator can guide a slack sling on to one of the sling retainer rods 56, 58. The slings are carefully ordered, depending on the order that the bundles of tubular members 31 are to be subsequently lifted off the platforms 28 and 28', during performance of a particular operation employing the tubulars 31 . Since the platforms 28 and 28' span the spacing 32 between the support towers 18 and 20, the operative is quite safe during this time. This is because the upright columns 34 and 36 of the towers 18 and 20 prevent the tubular members 31 from sliding off the platforms 28 or 28' and encroaching onto the walkway 26, whilst the snagging rails 52 and 54 prevent the tubulars from being lowered vertically into the walkway.

Folding ramps 88 are also provided on the walkway section 12, giving access to the walkway 26 whilst reducing trip hazards, whilst storage boxes 90 and 92, respectively are provided for storing slings, chain binders and other necessary equipment.

From the above, it will be understood that the bundles of tubular members 31 stacked on the platforms 28 and 28' are supported along a majority of their length, and restrained from movement under external loading in that they are held between the vessel side wall 82 and the support columns 34 and 36 of the support towers 18 and 20.

Fig. 9 shows a modular tubing rack system comprising two such modular tubing rack assemblies 10 and 10a, spaced out along a length of the vessel deck 38. Optionally however the tubing rack assemblies 10 and 10a can cooperate so that additional tubular members 31 can be stored in a space between the tubing rack assemblies 10, 10a. This is shown in Fig. 10. First tubing storage areas 94 and 94a are defined between side walls 82, 82' of the vessel 40 and the respective support towers 18, 20 and 18a, 20a. A second, common storage area 96 is defined between the support towers 18, 20 of the first tubing rack assembly 10 and the support towers 18a, 20a of the second tubing rack assembly 10a. Optionally and on a larger width vessel deck, a further tubing rack assembly may be provided and positioned between the first and second tubing rack assemblies 10, 10a to define further tubing storage areas. Various modifications may be made to the foregoing without departing from the spirit or scope of the present invention.

For example, reference is made herein to a tubing rack assembly comprising a walkway section having a first and at least one further support tower. Whilst reference is made to a tower, it will be understood that other structures, defining a safe working area and (optionally) at least one upright support, may be employed. At least one tubing support section of the modular tubing rack assembly may have a width which is different from a width of at least one other tubing support section. This may provide a greater ability to adjust a width of the assembly, for example to provide an assembly of a desired width and/or to suit a particular vessel deck.

The walkway section of the modular tubing rack assembly may comprise the first support tower, and the at least one further support tower may be a second support tower. The first support tower may be provided at, near or adjacent a first end of the walkway section platform. The second support tower may be provided at, near or adjacent a second end of the walkway section platform which is opposite to the first end. The walkway section may comprise at least one intermediate support tower disposed between the first and second support towers and defining a safe working area. The intermediate support tower may be positioned so that the walkway which is defined extends along the walkway platform from the working area defined by the first support tower, through the working area defined by the at least one intermediate support tower and to the working area defined by the second support tower. The sling retainer may be a post, rod, column, hook, clip or the like coupled to or forming part of the support tower.

Claims

1 . A modular tubing rack assembly for supporting and restraining a plurality of elongate tubular members on a deck of a vessel, the assembly comprising:

2. The modular tubing rack assembly of claim 1 , wherein the first and at least one further support tower of the walkway section are spaced apart by a distance which is less than a length of a tubular member which is to be positioned on the platform of the tubing support section.

3. The modular tubing rack assembly of claim 1 or claim 2, wherein the at least one tubing support platform is configured to receive a plurality of bundles of tubular members.

4. The modular tubing rack assembly of claim 3, wherein the plurality of bundles of tubular members are grouped together using a sling or slings.

5. The modular tubing rack assembly of any preceding claim, wherein the walkway section is releasably securable to the deck of the vessel and the tubing support section is releasably secured to the walkway section.

6. The modular tubing rack assembly of any preceding claim, wherein the length of the tubing support section platform is configured so that the tubular members which are to be stored on the platform are supported over a substantial part of their length, a majority of their length, or their entire length.

7. The modular tubing rack assembly of any preceding claim, wherein the assembly comprises at least one further tubing support section, the at least one further tubing support section being releasably securable to at least one of the walkway section, and to another tubing support section.

8. The modular tubing rack assembly of claim 7, wherein the further tubing support section is positionable to a side of the walkway section which is opposite to the side of the walkway section where the other tubing support section is positioned.

9. The modular tubing rack assembly of claim 7 or claim 8, wherein the assembly comprises a plurality of tubing support sections, each tubing support section being eatable on one or both sides of the walkway section.

10. The modular tubing rack assembly of any preceding claim, wherein the at least one tubing support section has a width, defining a width of the platform.

1 1 . The modular tubing rack assembly of any of claims 7 to 10, wherein at least one tubing support section has a width which is different from a width of at least one other tubing support section.

12. The modular tubing rack assembly of any preceding claim, wherein the support towers of the walkway section are positioned on the walkway platform or may extend from the walkway platform.

13. The modular tubing rack assembly of any preceding claim, wherein the support towers are provided integrally with the walkway section platform.

14. The modular tubing rack assembly of any preceding claim, wherein the walkway section comprises the first support tower, and the at least one further support tower is a second support tower.

15. The modular tubing rack assembly of claim 14, wherein the first support tower is provided at, near or adjacent a first end of the walkway section platform.

16. The modular tubing rack assembly of claim 14 or claim 15, wherein the second support tower is provided at, near or adjacent a second end of the walkway section platform which is opposite to the first end.

17. The modular tubing rack assembly of any of claims 14 to 16, wherein the walkway section comprises at least one intermediate support tower disposed between the first and second support towers and defining a safe working area.

18. The modular tubing rack assembly of claim 17, wherein the intermediate support tower is positioned so that the walkway which is defined extends along the walkway platform from the working area defined by the first support tower, through the working area defined by the at least one intermediate support tower and to the working area defined by the second support tower.

19. The modular tubing rack assembly of any of claims 14 to 18, wherein the spacing between the first support tower and the at least one further support tower may be defined between adjacent or facing parts of the towers.

20. The modular tubing rack assembly of any of claims 14 to 19, wherein the at least one tubing support section spans from the first support tower to the at least one further support tower, such that it bridges the spacing between the towers.

21 . The modular tubing rack assembly of any preceding claim, wherein the support towers are each be defined by a support tower structure.

22. The modular tubing rack assembly of claim 21 , wherein the support tower structure defines a perimeter of the working area.

23. The modular tubing rack assembly of claim 21 or claim 22, wherein the structure extends to a height above a surface of the walkway platform, the height being selected to be greater than the average height of an operator (typically at least 2m, and optionally up to around 2.5m), to provide protection for the operator.

24. The modular tubing rack assembly of any of claims 21 to 23, wherein a height dimension of the support towers is greater than at least one of a width and a length of the towers.

25. The modular tubing rack assembly of any preceding claim, wherein the support towers are adapted to support tubular members on both sides of the towers, and thus the walkway section.

26. The modular tubing rack assembly of any preceding claim, wherein each support tower has at least one upright support for supporting tubular members positioned laterally of the tower on the tubing support section platform.

27. The modular tubing rack assembly of claim 26, wherein the at least one upright support of each support tower is a column, post or the like forming part of the tower.

28. The modular tubing rack assembly of claim 26 or 27, wherein the support tower structure is a frame and the upright support is a member of the frame.

29. The modular tubing rack assembly of any of claims 26 to 28, wherein the upright support is substantially vertically oriented so that, in use, the support extends substantially perpendicularly to the deck of the vessel and/or to the walkway section platform.

30. The modular tubing rack assembly of any of claims 26 to 29, wherein the support towers comprises a plurality of upright supports, the support towers comprising at least one upright support on or at a first side of the tower, and at least one further upright support on or at a second side of the tower which is opposite the first side.

31 . The modular tubing rack assembly of any preceding claim, wherein the support towers comprise at least one upper cross-member, which define an upper extent of the safe working area.

32. The modular tubing rack assembly of any preceding claim, wherein each support tower comprises a sling retainer for retaining at least one sling, the sling extending, in use, around at least one tubular member positioned on the tubing support section.

33. The modular tubing rack assembly of claim 32, wherein the sling retainer is a post, rod, column, hook, clip or the like coupled to or forming part of the support tower.

34. The modular tubing rack assembly of any preceding claim, wherein the assembly further comprises at least one securing arrangement for releasably securing the tubing support section to the walkway section.

35. The modular tubing rack assembly of claim 34, wherein the securing arrangement is releasably operable.

36. The modular tubing rack assembly of claim 34 or claim 35, wherein the securing arrangement comprises a first securing component provided on the tubing support section and a second securing component provided on the walkway section, the first securing component mating with the second securing component to secure the tubing support section to the walkway section.

37. The modular tubing rack assembly of claim 36, wherein one of the first and second securing components is a male component and the other one of the first and second securing components is a female component.

38. The modular tubing rack assembly of claim 36 or claim 37, wherein the securing arrangement comprises a locking element such as a pin, bolt or the like for locking the first securing component to the second securing component.

39. The modular tubing rack assembly of any of claims 7 to 38, wherein the at least one further tubing section includes at least one securing arrangement for releasably securing the tubing support section to the walkway section.

40. The modular tubing rack assembly of any preceding claim, wherein the walkway platform and the tubing support platform of the at least one tubing support section are substantially planar and elongate.

41 . A modular tubing rack system comprising:

a first modular tubing rack assembly according to any of claims 1 to 40; and a second modular tubing rack assembly according to any of claims 1 to 40;

in which the first and second modular tubing rack assemblies are each arranged to define first tubing storage areas between the support towers of their walkway sections and a part of the vessel, and second tubing storage areas between the support towers of their walkway sections and the support towers of another modular tubing rack assembly.

42. The modular tubing rack system of claim 41 , wherein the first and second modular tubing rack assemblies are each arranged to define first tubing storage areas between the support towers of their walkway sections and a wall of the vessel.

43. The modular tubing rack system of claim 41 or claim 42, wherein the system further comprises a third modular tubing rack assembly according to any of claims 1 to 40, the third assembly adapted to be positioned between the first and second modular tubing rack assemblies.

44. The modular tubing rack system of claim 43, wherein the third modular tubing rack assembly being arranged to define: a first tubing storage area between the support towers of its walkway section and the support towers of the first modular tubing rack assembly; and a second tubing storage area between the support towers of its walkway section and the support towers of the second modular tubing rack assembly.

45. A method of supporting and restraining a plurality of elongate tubular members on a deck of a vessel, the method comprising the steps of:

arranging a platform of the tubing support section so that it spans from the first support tower to said further support tower;

releasably securing said tubing support section to the walkway section; and