A conduit support system

Abstract

A conduit support system A conduit support system for a subsea conduit, which comprises: a conduit guide for receiving and guiding the conduit, the conduit guide being movable and comprising a first portion, which extends along a longitudinal axis, and a second portion, which extends from an end of the first portion and is arranged at an angle to the longitudinal axis; a bracket for supporting the conduit guide, the bracket engaging the first portion of the conduit guide and guiding movement thereof in a direction of the longitudinal axis; and a locking mechanism for selectively locking the conduit guide against movement along the longitudinal axis.

Description

[0001] A conduit support system

[0002] The present disclosure relates to a conduit support system. In particular, to such a system suitable for supporting a subsea conduit.

[0003] Subsea conduits take a number of different forms, and include, for example, flexible subsea cables, umbilicals and pipes.

[0004] Subsea cables are used for transmitting electrical power underwater. They are used, for example, in offshore energy generation, and in the oil and gas industries. Subsea cables are used for the transmission of electricity generated by the individual wind turbines within an offshore wind farm. They carry electricity from the turbines, typically to an offshore substation, where it is collected, transformed, and then transmitted via further subsea cables to the grid onshore. Offshore oil and gas platforms require substantial electrical power for operations, which is supplied through subsea cables, connecting these platforms to power sources onshore, to nearby oil rigs, or otherwise.

[0005] Subsea umbilicals comprise multi-cored pipe and power assemblies. They may be used in subsea applications to deliver any required combination of power, control signals, hydraulic fluids, and chemicals.

[0006] Pipes may be used, for example, to transport products from the seabed to an above water processing facility and vice versa.

[0007] Given the harsh and dynamic offshore environment, the design, installation, and maintenance of these conduits poses a number of challenges.

[0008] Regardless of the specific application, subsea conduits typically require attachment to a subsea structure. In the case of an offshore wind turbine, the conduit may be attached, for example, to a monopile foundation, a jacket foundation, a gravity-based foundation, a floating platform, or a tripod foundation.It is necessary to attach conduit support arrangements to the subsea structures at a level above the seabed. Among the reasons for this is the fact that conduit support arrangements must be attached in advance of the laying / attachment of conduits. If the conduit support arrangements are on the seabed, they are liable to become clogged with debris prior to the installation of the conduits. Since the conduit supports are attached above the seabed, there is a portion of conduit, that extends unsupported in a region between the attachment point to the subsea structure and the seabed, which is highly vulnerable to damage.

[0009] The prior art solution to the problem has been to provide conduit protection systems, which may include multi-part / multilayered protective sleeves. Whilst these provide a clear improvement over unprotected conduits, the failure rates remain high. Failures are very costly to rectify. Moreover, the installation of the conduit protection systems is awkward and also costly.

[0010] The present invention arose as a result of work looking to provide an improved solution for the attachment of subsea conduits to subsea structures.

[0011] Representative features are set out in the following clauses, which stand alone or may be combined, in any combination, with one or more features disclosed in the text and / or drawings of the specification.

[0012] The term subsea conduit as used herein is intended to cover any flexible cable, pipe, hose or umbilical for delivering any one or more of power, control signals, hydraulic fluids, or chemicals in a subsea environment. The present invention is not to be limited to any particular form of subsea conduit.

[0013] According to the present invention, in a first aspect, there is provided a conduit support system for a subsea conduit, which comprises: a conduit guide for receiving and guiding the conduit, the conduit guide being movable and comprising a first portion, which extends along a longitudinal axis, and a second portion, which extends from an end of the first portion and is arranged at an angle to the longitudinal axis; a bracket for supporting the conduit guide, the bracket engagingthe first portion of the conduit guide and guiding movement thereof in a direction of the longitudinal axis; and a locking mechanism for selectively locking the conduit guide against movement along the longitudinal axis.

[0014] The orientation of the longitudinal axis, in use, will be dependent on the orientation of the portion of the subsea structure to which the conduit support system is attached. It may be vertical or may be at an angle to vertical. It will be vertical, for example, when attached to a monopile foundation of a wind turbine. It may be at an angle to the vertical, for example, when attached to the angled leg of a jacket foundation. The angled second portion allows for a smooth transition in the path of the guided conduit between the (upstanding) longitudinal axis and the seabed.

[0015] By virtue of the movable conduit guide, the conduit support system may be attached to a subsea structure such that the conduit guide is initially spaced from seabed, i.e. , such that a lowermost point of the conduit guide is spaced from the seabed. Subsequently, at the time of conduit installation (or very shortly before), the conduit guide may then be lowered until it is brought into contact with the seabed or a landing surface, or is only a short distance therefrom, such that any unsupported length of conduit is minimised. Accordingly, there is no, or only a minimal, unsupported length of conduit between a mouth / exit of the conduit guide and the seabed or landing surface, and installation issues are obviated.

[0016] A drive mechanism is provided for moving the conduit guide in the direction of the longitudinal axis, i.e. downwardly. The drive mechanism, or at least a portion thereof, is supported by the bracket. The drive mechanism preferably comprises a geared drive. The drive mechanism may comprise a rack and pinion. The drive mechanism is preferably operated by a remotely operated vehicle, ROV. The drive mechanism may comprise an ROV torque tool bucket for such purposes.

[0017] The second portion of the conduit guide is preferably curved. The first and second portions are preferably unitarily formed.

[0018] A third portion is preferably provided, wherein the second portion extends between the first portion and third portions. The third portion preferably extendslongitudinally, along a second longitudinal axis which is arranged at an angle to the first longitudinal axis. The second longitudinal axis is preferably substantially horizontal in use. In such a case, the third portion may lie on the seabed. A plate is preferably attached to the third portion. The plate may comprise a ‘mud mat’. The plate is preferably provided with a plurality of through openings. The plate is preferably provided on an underside of the third portion in use. The plate is preferably parallel to the second longitudinal axis, or to the seabed or a landing surface, such that a plane of the plate is substantially horizontal in use.

[0019] The first, second and third portions are preferably unitarily formed. They may otherwise be separately formed and joined together. Regardless, it is preferable that they are fluid tight with one another.

[0020] There is preferably an enlarged mouth provided at an end of the third portion. An enlarged mouth aids in the introduction of conduits up through the conduit guide. The mouth may comprise a half bell mouth.

[0021] The conduit guide preferably comprises a tube. The tube preferably has a round profile; however, it may have a square profile or otherwise. The conduit guide is preferably rigid. The conduit guide is preferably formed from metal.

[0022] The bracket preferably comprises a collar for attachment of the bracket to a subsea structure. It may comprise a split collar.

[0023] The conduit support system preferably comprises a secondary conduit guide, which is positioned above the conduit guide in use. The secondary conduit guide is preferably fixed, such that movement of the conduit guide is relative to the fixed secondary conduit guide. The conduit guide and secondary conduit guide are preferably fluid tight with one another. One or more seals may be provided between the conduit guide and the secondary conduit guide. The secondary conduit guide is preferably co-axial with the first portion of the conduit guide. The conduit guide and the secondary conduit guide are preferably telescopically engaged. In such case the conduit guide is preferably received by the secondary conduit guide. One or moreseals may be provided between the inner surface of the secondary conduit guide and an outer surface of the conduit guide.

[0024] According to the present invention in a further aspect, there is provided a method comprising: installing a conduit support system as defined in any preceding paragraph on a subsea structure by attaching the bracket to the subsea structure, whilst the conduit guide is locked in a first, raised, position above the seabed or a landing surface; unlocking the conduit guide and lowering the conduit guide to a second, lowered, position, in which the conduit guide is closer to or contacts the seabed or the landing surface; and pulling the subsea conduit through the conduit guide. The conduit guide may be locked into its second, lowered, position prior to the conduit being pulled through the conduit guide.

[0025] The subsea conduit may comprise a flexible cable, umbilical or pipe.

[0026] Further, preferable, features will be apparent from the dependent claims and the description.

[0027] Non-limiting embodiments of the invention will now be discussed with reference to the following drawings:

[0028] Figure 1 shows a perspective view of a conduit support system for a subsea conduit;

[0029] Figure 2 shows a side view of the conduit support system of Figure 1 in a first, raised, position;

[0030] Figure 3 shows a side view of the conduit support system of Figure 1 in a second, lowered, position, and includes a detail view of a sealing arrangement;

[0031] Figure 4 shows a partial front view of a bracket of the conduit support system of Figure 1, including a drive mechanism; and

[0032] Figure 5 shows a partial plan view of a lower end of a conduit guide of the conduit support system of Figure 1.

[0033] With reference to Figures 1 to 3, there is shown a conduit support system for a subsea conduit. The conduit support system comprises a conduit guide 1 forreceiving and guiding the conduit (not shown). The conduit guide 1 is movable and comprises a first portion 1a, which extends along a longitudinal axis LA1 , and a second portion 1b, which extends from an end of the first portion at an angle to the longitudinal axis LA1. A bracket 2 is provided for supporting the conduit guide 1. The bracket 2 engages the first portion 1a of the conduit guide 1 and guides movement of the conduit guide 1 in a direction of the longitudinal axis LA1 (i.e. vertically in the depicted arrangement in which the conduit support system is attached to a monopile foundation 3 of a wind turbine). A locking mechanism 4 is provided for selectively locking the conduit guide against movement along the longitudinal axis LA1.

[0034] As discussed, the conduit support system may be attached to a subsea structure 3, of any appropriate form, such that the conduit guide 1 is initially spaced from seabed, i.e., such that a lowermost point of the conduit guide 1 is spaced from / raised up off the seabed. Figure 2 shows the conduit guide in a raised position. Subsequently, at the time of conduit installation (or very shortly before), the conduit guide may then be lowered until it is brought into contact with the seabed 5, as seen in Figure 3. Accordingly, in the installed stated there is no unsupported length of conduit between a mouth / exit 6 of the conduit guide and the seabed 5.

[0035] The subsea conduit to be received and guided by the conduit support system may, for example, comprise a flexible subsea cable, umbilical or pipe.

[0036] As noted, the orientation of the longitudinal axis LA1, in use, will be dependent on the orientation of the portion of the subsea structure 3 to which the conduit support system is attached. Whilst it is vertical in the depicted arrangement, in alternative arrangements it may be at an angle to vertical. The angled second portion 1b allows for a smooth transition in the path of the guided conduit between the (upstanding) longitudinal axis LA1 and the seabed 5. The second portion 1b of the conduit guide is preferably curved, as shown. The first and second portions 1a, 1 b are preferably unitarily formed.

[0037] A drive mechanism 7 is provided for moving the conduit guide 1 in the direction of the longitudinal axis LA1, i.e. downwardly, from the position in Figure 2 tothe position in Figure 3. The drive mechanism 7, or at least a portion thereof, is supported by the bracket 2, as shown. The drive mechanism 7 preferably comprises a geared drive. The drive mechanism 7 may comprise a rack 8 and pinion 9. In alternative arrangements, the drive mechanism may be other than a geared drive, as will be appreciated by those skilled in the art. In the depicted exemplary arrangement, the drive mechanism comprises a pair of racks 8 attached to the first portion 1a and a corresponding pair of pinions 9 attached to the bracket 2. The drive mechanism 7 is preferably operated by a remotely operated vehicle, ROV. The drive mechanism 7 may comprise an ROV torque tool bucket 10 for such purposes. It is preferable in an arrangement as shown, that there is suitable gearing provided such that both racks 8 and pinions 9 are synchronously driven through a single torque tool bucket 10. The locking mechanism 4 may comprise part of the drive mechanism, and may comprise any suitable locking arrangement, as will be readily appreciated by those skilled in the art. It may, for example comprise a ratchet mechanism, one or more locking pins, which may be spring-loaded, a friction clutch mechanism, a cam lock mechanism, a detent mechanism, or a pinion with dual engagement teeth.

[0038] A third portion 1c is preferably provided, wherein the second portion 1b extends between the first portion 1a and third portions 1c. The third portion 1c preferably extends longitudinally from an end of the second portion along a second longitudinal axis LA2, which is arranged at an angle to the first longitudinal axis LA1. In the depicted arrangement the axes LA1 , LA2 are perpendicular to one another. A portion of the conduit, having been redirected by the second potion 1b will be guided (and protected) by the third portion 1c in a straight line for a distance before exiting the conduit guide 1. Regardless of the orientation of the first longitudinal axis LA1 , the second longitudinal axis LA2 is preferably substantially horizontal in use, as shown. The third portion 1c preferably lies on the seabed 5. A plate 14 is preferably attached to the third portion 1c. The plate 14 may comprise a ‘mud mat’. The plate 14 is preferably provided with a plurality of through openings 15. The plate 14 is preferably provided on an underside of the third portion 1c in use. The plate 14 preferably has a greater width than the third portion 1c. The plate 14 is preferably parallel to the second longitudinal axis LA2, such that a plane of the plate is substantially horizontal in use.The first, second and third portions 1a, 1b, 1c are preferably unitarily formed. They may otherwise be separately formed and joined together. Regardless, it is preferable that they are fluid tight with one another.

[0039] There is preferably an enlarged mouth 6 provided at an end of the third portion. An enlarged mouth aids in the introduction of conduits up through the conduit guide and limits rubbing / wear with the conduit should it be moved by the sea following installation. The mouth 6 may comprise a half bell mouth 13.

[0040] The conduit guide 1 preferably comprises a tube, as shown. The tube preferably has a round profile, as again seen. However, it may take other forms and may, for example, have a square profile or otherwise. The conduit guide 1 is preferably rigid. It may be formed from metal.

[0041] The bracket 2 preferably comprises a collar 16 for attachment of the bracket to a subsea structure 3. It may comprise a split collar, clamped around the subsea structure with bolts. It may take alternative forms to suit installation requirements and / or the form of the subsea structure 3 to which it is attached.

[0042] The conduit support system preferably comprises a secondary conduit guide 11 , which is positioned above the conduit guide 1 in use, as seen. The secondary conduit guide 11 is preferably fixed to the subsea structure 3, such that movement of the conduit guide 1 is relative to the fixed secondary conduit guide 11. The conduit guide 1 and secondary conduit guide 11 are preferably fluid tight with one another. One or more seals 12 may be provided between the conduit guide 1 and the secondary conduit guide 11 , as shown in the detail view of Figure 3. The secondary conduit guide 11 is preferably co-axial with the first portion 1a of the conduit guide, as shown. The conduit guide 1 and the secondary conduit guide 11 are preferably telescopically engaged. In such case the conduit guide 1 is preferably received by the secondary conduit guide 11 , as shown. The one or more seals 12 may be provided between an inner surface of the secondary conduit guide 11 and an outer surface of the first portion 1a of the conduit guide 1 in such case.As noted, the conduit guide, as exemplarily discussed above, allows for installation as follows: the bracket 2 is attached to the subsea structure 3, whilst the conduit guide is locked in the first, raised, position (as seen in Figure 2) above the seabed. Subsequently, at an appropriate time, the conduit guide 1 is unlocked and lowered to the second position, in which the conduit guide contacts the seabed (as seen in Figure 3). The conduit guide 1 may then be locked in the lowered position. However, the locking step may not be required. Following installation, a subsea conduit to be guided by the conduit support system, may be inserted through the mouth 6 and pulled up through the guide for suitable connection.

[0043] Numerous alternative arrangements and modifications to the embodiments as described herein will be readily appreciated by those skilled in the art within the scope of the appended claims. In particular, features of the described embodiments may be readily combined.

[0044] When used in this specification and claims, the terms "comprises" and "comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.

[0045] The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

[0046] Although certain example embodiments of the invention have been described, the scope of the appended claims is not intended to be limited solely to these embodiments. The claims are to be construed literally, purposively, and / or to encompass equivalents.

Claims

Claims1. A conduit support system for a subsea conduit, which comprises:a conduit guide for receiving and guiding the conduit, the conduit guide being movable and comprising a first portion, which extends along a longitudinal axis, and a second portion, which extends from an end of the first portion and is arranged at an angle to the longitudinal axis;a bracket for supporting the conduit guide, the bracket engaging the first portion of the conduit guide and guiding movement thereof in a direction of the longitudinal axis;a locking mechanism for selectively locking the conduit guide against movement along the longitudinal axis; anda drive mechanism for moving the conduit guide in the direction of the longitudinal axis, wherein the drive mechanism is supported by the bracket.

2. A conduit support system as claimed in Claim 1 , wherein the drive mechanism comprises a geared drive.

3. A conduit support system as claimed in Claim 1 or 2, wherein the drive mechanism comprises a rack and pinion.

4. A conduit support system as claimed in any of Claims 1 to 3, wherein the drive mechanism comprises a remotely operated vehicle, ROV, torque tool bucket.

5. A conduit support system as claimed in any preceding claim, wherein the second portion of the conduit guide is curved.

6. A conduit support system as claimed in any preceding claim, wherein the first and second portions are unitarily formed.

7. A conduit support system as claimed in any preceding claim, wherein the second portion extends between the first portion and a third portion, wherein the third portion extends along a second longitudinal axis, which is arranged at an angle to the first longitudinal axis.

8. A conduit support system as claimed in Claim 7, wherein the second longitudinal axis is substantially horizontal in use.

9. A conduit support system as claimed in Claim 7 or 8, wherein the first, second and third portions are unitarily formed.

10. A conduit support system as claimed in any of Claims 7 to 9, wherein a plate is attached to the third portion.

11. A conduit support system as claimed in Claim 10, wherein the plate is provided with a plurality of through openings.

12. A conduit support system as claimed in any of Claims 7 to 11 , wherein an enlarged mouth is provided at an end of the third portion.

13. A conduit support system as claimed in any preceding claim, wherein the conduit guide comprises a tube.

14. A conduit support system as claimed in any preceding claim, wherein the conduit guide is rigid.

15. A conduit support system as claimed in any preceding claim, wherein the conduit guide is formed from metal.

16. A conduit support system as claimed in any preceding claim, wherein the bracket comprises a collar for attachment of the bracket to a subsea structure.

17. A conduit support system as claimed in any preceding claim, wherein a secondary conduit guide is provided, the secondary conduit guide being positioned above the conduit guide in use.

18. A conduit support system as claimed in Claim 17, wherein the secondary conduit guide is fixed, such that movement of the conduit guide is relative to the fixed secondary conduit guide.

19. A conduit support system as claimed in Claim 17 or 18, wherein the secondary conduit guide is co-axial with the first portion of the conduit guide.

20. A conduit support system as claimed in Claim 19, wherein the conduit guide and the secondary conduit guide are telescopically engaged.

21. A conduit support system as claimed in Claim 20, wherein one or more seals are provided between the conduit guide and the secondary conduit guide.

22. A method of attaching a subsea conduit to a subsea structure, the method comprising:installing a conduit support system as claimed in any preceding claim on a subsea structure by attaching the bracket to the subsea structure, whilst the conduit guide is locked in a first, raised, position above the seabed or a landing surface; unlocking the conduit guide and lowering the conduit guide to a second, lowered, position, in which the conduit guide is closer to or contacts the seabed or landing surface; andpulling the subsea conduit through the conduit guide.

23. A method as claimed in Claim 22, wherein the subsea conduit comprises a flexible cable, umbilical or pipe.

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