CONDUIT ANCHOR

Abstract

Disclosed is conduit anchor, an offshore system comprising a conduit anchor and a method of deployment. The conduit anchor includes a base section adapted for attachment to a conduit, and a conduit guide extending from the base section. In use a dynamic conduit extends along a dynamic conduit pathway range defined by the anchor, via the conduit guide. The conduit guide comprises a convex bend protecting surface region oriented towards the dynamic conduit pathway range which in use protects against over bending of the dynamic conduit.

Claims

1. A conduit anchor comprising: a base section; and a conduit guide extending from the base section; wherein the base section comprises a conduit attachment for securing a static conduit portion to the base section; wherein the conduit anchor defines a dynamic conduit pathway range, available in use to a dynamic conduit portion extending distally from the conduit attachment via the conduit guide; and wherein the conduit guide comprises a convex bend protecting surface region oriented towards the dynamic conduit pathway range and distally from the conduit attachment; and the convex bend protecting surface region extending at least partially around the dynamic conduit pathway range.

2. The conduit anchor of claim 1, for use with a dynamic conduit portion having a minimum bend radius, wherein the radius of curvature of all parts of the convex bend protecting surface region along the dynamic conduit pathway range is at or above the minimum bend radius of the dynamic conduit portion.

3. The conduit anchor of claim 1, wherein when the conduit anchor rests on the seabed, the dynamic conduit pathway range extends distally from the conduit attachment generally along the seabed.

4. (canceled)

5. The conduit anchor of claim 1, wherein when the conduit anchor rests on the seabed, the dynamic conduit pathway range extends distally from the conduit attachment generally away from the seabed.

6. The conduit anchor of claim 5, wherein when the conduit anchor rests on the seabed, the bend protecting surface region extends completely around the dynamic conduit pathway range and defines an aperture around the dynamic conduit pathway range through which the dynamic conduit portion extends in use.

7. The conduit anchor of claim 1, wherein convex bend protecting surface region provides bend protection to a dynamic conduit portion extending along the dynamic conduit pathway range through at least about 90 degrees, or at least about 180 degrees.

8. The conduit anchor of claim 1, wherein the convex bend protecting surface region comprises more than one convex bend protecting surface section.

9. The conduit anchor of claim 1, wherein the or each convex bend protecting surface section has a substantially part-circular cross section.

10. The conduit anchor of claim 9, wherein the bend protecting surface region comprises two, three, four or more convex bend protecting surface sections having a part-circular cross section constructed from two, three, four or more lengths of a tubular joined end to end around the dynamic conduit pathway range.

11. (canceled)

12. (canceled)

13. The conduit anchor of claim 10, wherein when the conduit anchor rests on the seabed, the dynamic conduit pathway range extends distally from the conduit attachment generally away from the seabed, and wherein the bend protecting surface region comprises four part-cylindrical surface sections, defining an aperture having generally square or rectangular symmetry around the dynamic conduit pathway range.

14. (canceled)

15. (canceled)

16. The conduit anchor of claim 1, wherein the conduit attachment includes means to join separate dynamic and static conduits.

17. The conduit anchor of claim 16, wherein the conduit attachment comprises a proximal end for attachment to a static conduit, and a distal end for attachment to a dynamic conduit.

18. (canceled)

19. The conduit anchor of claim 16, wherein the conduit attachment further comprises strain relief apparatus.

20. (canceled)

21. The conduit anchor of claim 1, wherein the conduit attachment comprises a bend stiffener extending from the distal end thereof.

22. (canceled)

23. (canceled)

24. An offshore system comprising: an installation on the surface of a body of water; a conduit anchor comprising: a base section; and a conduit guide extending from the base section; wherein the base section comprises a conduit attachment for securing a static conduit portion to the base section; wherein the conduit anchor defines a dynamic conduit pathway range, available in use to a dynamic conduit portion extending distally from the conduit attachment via the conduit guide; and wherein the conduit guide comprises a convex bend protecting surface region oriented towards the dynamic conduit pathway range and distally from the conduit attachment; and the convex bend protecting surface region extending at least partially around the dynamic conduit pathway range; and a conduit; the conduit comprising a dynamic conduit portion and a static conduit portion; wherein the conduit is attached to the conduit attachment of the conduit anchor, wherein the static conduit portion extends from proximal of the conduit attachment to the conduit attachment and the dynamic conduit portion extends distally from the conduit attachment along the dynamic conduit pathway range, via the conduit guide, and through the water column to the surface installation.

25. The offshore system of claim 24, wherein the dynamic conduit portion comprises a minimum bend radius and the radius of curvature of all parts of the convex bend protecting surface region along the dynamic conduit pathway range is at or above the minimum bend radius of the dynamic conduit portion.

26. (canceled)

27. The offshore system of claim 24, wherein the installation on the surface of the body of water comprises a floating water power current generator.

28. A method for deploying a conduit anchor from an installation on the surface of a body of water, wherein the conduit anchor comprises: a base section; and a conduit guide extending from the base section; wherein the base section comprises a conduit attachment for securing a static conduit portion to the base section; wherein the conduit anchor defines a dynamic conduit pathway range, available in use to a dynamic conduit portion extending distally from the conduit attachment via the conduit guide; and wherein the conduit guide comprises a convex bend protecting surface region oriented towards the dynamic conduit pathway range and distally from the conduit attachment; and the convex bend protecting surface region extending at least partially around the dynamic conduit pathway range; and the method comprising; attaching a conduit to the conduit attachment; and lowering the conduit anchor to the seabed, whereby when the conduit anchor is resting on the seabed a static conduit portion of the conduit extends from proximal of the conduit attachment to the conduit attachment and the dynamic conduit portion extends distally from the conduit attachment along the dynamic conduit pathway range, via the conduit guide, and through the water column to the surface installation.

29. The method of claim 28, comprising connecting a dynamic conduit to the conduit attachment by passing an end of the dynamic conduit, via the conduit guide, to the conduit attachment.

30. (canceled)

31. The method of claim 29, comprising connecting the dynamic conduit and a static conduit on the surface of the body of water; and then lowering the conduit anchor to the seabed.

32. (canceled)

33. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0119] Example embodiments now be described with reference to the following Figures in which:

[0120] FIG. 1 is a perspective view of an embodiment of a conduit anchor.

[0121] FIG. 2 is a side view of the conduit anchor in FIG. 1.

[0122] FIG. 3 is a cross sectional side view of the conduit anchor in FIGS. 2 and 3 showing a static conduit portion and a dynamic conduit portion extending along the dynamic conduit pathway range defined by the conduit anchor.

[0123] FIG. 4 is a perspective view of another embodiment of a conduit anchor with ballast weights attached.

[0124] FIG. 5 is a cross sectional side view of the conduit anchor of FIG. 4.

[0125] FIGS. 6a and 6b show an offshore system comprising a conduit anchor.

[0126] FIGS. 7a to 7c show a strain relief apparatus.

DETAILED DESCRIPTION

[0127] FIGS. 1, 2 and 3 show a conduit anchor 100. The conduit anchor 100 has a base section 102 and a conduit guide 104 extending from the base section. The base section 102 comprises a conduit attachment 106 for securing a conduit 108 to the base section 102. The conduit 108 includes a static conduit portion 108a and a dynamic conduit portion 108b.

[0128] In the example shown the dynamic and static portions are separate dynamic and static conduits attached to respective ends of the conduit attachment (discussed in further detail below), but in alternative embodiments the conduit 108 is contiguous.

[0129] The dynamic conduit portion 108b extends in use distally from the conduit attachment 106 through the water column to a vessel on the water surface, while the static conduit portion 108a extends proximally along the seabed, typically to an export pipeline, or power distribution network or the like. The proximal and distal orientations in relation to the conduit attachment 106 are illustrated by the arrows marked P and D, respectively in the Figures.

[0130] The cable anchor 100 defines a dynamic conduit pathway range which extends distally from the conduit attachment 106 via the conduit guide 104, which incorporates all of the pathways along which the dynamic conduit 108b can follow, as illustrated by dotted pathways 110a-d in FIG. 3. It will be understood that the dynamic conduit pathway range diverges also laterally, in the embodiment shown.

[0131] Also illustrated in FIG. 3 is the notional dynamic conduit axis A, extending linearly from the distal end of the conduit attachment 106, generally along the seabed in normal use. The dynamic conduit pathway range extends and diverges symmetrically around the axis A laterally.

[0132] The conduit guide includes a convex bend protecting surface region 112 oriented towards the dynamic conduit pathway range and which is also oriented distally in relation to the conduit attachment 106. The proximal face 105 of the conduit guide 104 does not for example form part of the bend protecting surface region 112, since it is oriented proximally in relation to the conduit attachment.

[0133] The convex bend protecting surface region 112 has a radius of curvature which, in the embodiment shown, slightly exceeds minimum bend radius of the dynamic conduit 108b, and thereby prevents the dynamic conduit 108 from having a curvature below its minimum bend radius.

[0134] The conduit guide 104 is constructed from three tubular bend protecting surface structures 104a, 104b and 104c connected end-to-end orthogonally. The tubular structures each comprise a part-cylindrical surface, having part-circular cross sections, providing bend protection to the dynamic conduit 108b through around 180 degrees of curvature.

[0135] In other embodiments, the bend protecting surface region may include other curvatures, as disclosed herein.

[0136] The conduit guide 104, and more particularly the bend protecting surface region 112 extends in use over and to each side of the dynamic conduit pathway range. The dynamic conduit pathway range is bounded around the remaining part of its circumference in part by the base section 102 and the seabed. The base section 102 and convex bend protecting surface region 112 together define an aperture 120 through which the dynamic conduit 108b extends in use.

[0137] The conduit attachment 106 includes in this embodiment a “splicing box” having at its proximal end a conduit connector 106a for connection to the static conduit 108a, and at its distal end a conduit connector 106b for connection to the dynamic conduit 108b.

[0138] The embodiment shown is for connection of electrical distribution cables and the conduit attachment also provides an intermediate conduit portion extending between the connectors 106a and 106b.

[0139] Extending from the distal end of the conduit attachment 106 is a bend stiffener 114, in the form of an elastomeric sheath. In use the dynamic cable 108 is introduced through the bend stiffener, as shown in FIG. 1. The bend stiffener 114 extends partially into the region of the dynamic cable pathway range defined by the bend protecting surface region 112. Although the bend stiffener 114 is shown extending along the axis A in the figures, in use it will bend together with the dynamic conduit 108 within the bounds of the dynamic conduit pathway range.

[0140] In alternative embodiments, the bend stiffener is applied directly to a dynamic conduit portion prior to connection to the anchor, or may be omitted entirely.

[0141] The base section 102 is constructed from beams 102a, 102b, 102c and 102d and provides a stable platform to rest on a sea bed in use. In addition, the beams around the periphery 102a-c may be weighed down or ballasted after the anchor has been deployed, by ballast weights such as concrete blocks or the like.

[0142] In the embodiment shown the conduit guide 104 is of hollow construction and may also be filled with a ballasting material. In alternative embodiments (not shown) the conduit guide may be cast of machined as a solid block, or formed from an open framework. The construction and ballasting of the conduit anchor can be varied according to the intended means of deployment. In some circumstances for example it may be preferable for the anchor not to be ballasted at the surface, and ballasted or otherwise pinned or bolted to the seabed. In other circumstances, such as in deeper water where post-deployment access is more difficult, it may be preferable for the anchor to be ballasted at the surface.

[0143] To deploy the anchor 100, a static conduit 108a is retrieved (e.g. floated) from the seabed and a dynamic conduit 108b provided on a surface installation such as a vessel. The cables 108a and 108b are connected to the respective ends of the conduit attachment 106. In particular the dynamic cable 108a is introduced through the aperture 120 via the conduit guide 104, in this embodiment into the cable stiffener 114.

[0144] The hollow portion of the conduit guide (not shown) is then filled with a ballasting material such as metallic pellets and the anchor deployed to the seabed.

[0145] The bend protecting surface regions provide a greater degree of tolerance to the final orientation of the anchor than would otherwise be possible.

[0146] FIGS. 4 and 5 show another example of a conduit anchor 200. Features in common with the conduit anchor 100 are provided with like reference numerals, incremented by 100.

[0147] The anchor 200 includes a base section 202 and mounted thereto by a framework 203 is a conduit guide 204.

[0148] The conduit guide is constructed from four tubular bend protecting surface structures 204a, b, c and d connected end-to-end orthogonally to define an aperture 220 through the conduit guide 204. Accordingly, the convex bend protecting surface region 212 extends completely around the dynamic cable pathway range (the axis A of which is marked in the Figure).

[0149] The conduit attachment in this instance includes a 90 degree bend, such that the proximal cable 208a extends to the proximal end 206a along the seabed in use, and the distal cable portion exits the distal end 206b generally vertically through the aperture 220, away from the seabed. Consequently, the dynamic cable pathway range extends initially generally vertically distally from the conduit attachment 206. This orientation, together with the convex bend protecting surface region 212 extending completely around the dynamic conduit pathway range provides for the dynamic cable pathway range to diverge in 360 degrees from the distal end 206b of the attachment 206, as illustrated by the example pathways 210a-d shown in FIG. 5.

[0150] The degree of bend protection also extends for between 90 and 180 degrees (i.e. away from the axis A) to permit the dynamic conduit 108b to bend back on itself and rest on the seabed, if required.

[0151] In alternative embodiments (not shown) the cable guide 104 may be open-sided (e.g. generally U-shaped) and provide bend protection only around a part of the dynamic conduit pathway range. Such an embodiment may provide for more convenient attachment of a conduit in some circumstances, for example when attachment is conducted at the seabed.

[0152] Also visible in FIG. 4 are ballast weights 222 on the base section 202. The ballast weights may be added at the water surface before deployment, or on the seabed.

[0153] FIGS. 6a and 6b schematically illustrate the utility of the conduit anchor in accordance with the invention. FIGS. 6a an 6b show an offshore system including an installation of the surface 301 of a body of water, in the example shown a floating tidal generator (water current power generator) 300, comprising nacelles 302 and rotors 304 for capturing energy from flowing water.

[0154] The generator 300 is anchored via anchor lines 306 in a conventional manner. In order to accommodate tidal variations, weather conditions (rough sea, currents etc) and the nominal pitch and roll experienced due to loads transferred via the rotors 304, the anchor lines must be provided with a degree of slack, in turn permitting some movement of the vessel 300 in relation to the seabed.

[0155] The generator 300 is connected to an electrical distribution system via a static electrical cable 308a on the seabed 303. The static cable 308a is a spur with onward connection to a subsea cable network (not shown). The static cable 308a is connected to the conduit attachment 106 of the anchor 100 as described above.

[0156] A dynamic cable 308b extends from the generator 300 through the water column to the anchor 100. The dynamic cable is connected to the distal end of the conduit attachment 106 as described above, and extends distally therefrom along the dynamic cable pathway range via the conduit guide 104.

[0157] As the generator 300 moves on the surface (for example between the flow conditions to the right as in FIG. 6a and to the left as in FIG. 6b), the angle through which the dynamic cable 308b is prone to bend will vary. The tidal and other environmental conditions experienced by the generator 300 may also be experienced to some degree by the dynamic cable 308b extending through the water column, also giving rise to variations in its pathway.

[0158] Whilst the anchor may be positioned relatively optimally for certain conditions, such as the high flow conditions shown in FIG. 6a (in which the dynamic cable is urged to a pathway in which it extends distally from the anchor 100 at a relatively shallow angle), the position may be less optimised at other times. For example, as shown in FIG. 6b, the generator 300 has moved further over the anchor 100 and the dynamic cable 308b is bent back on itself against the cable guide 104. The convex bend protecting surface region 112 in such circumstances prevents over bending, fatigue and potential breakage which might otherwise occur

[0159] Additional tensile strain relief for the dynamic conduit portion may be provided, such as a stain relief line disclosed herein. FIGS. 7a to 7c illustrate the provision of strain relief via a flange portion of a dynamic conduit.

[0160] A dynamic conduit 408b may take the form of an armoured cable, armoured optical fibre or the like, having an inner core 450 (such as an electrical cable or cable bundle, optical fibre bundle or the like) and an outer armoured layer 452, typically in the form of one or more helically wound braids.

[0161] At the proximal end 454 of the dynamic cable 408b, a proximal portion 452a of the armoured layer can be outwardly splayed to form a flange portion 456.

[0162] The proximal end 454 is then attached to the distal end 406b of a conduit attachment, such that the flange portion 456 of the dynamic conduit 408b is against a flange 407 at the distal end of the conduit attachment. The flange portion may then be clamped between the flange 407 and a collar 458, by bolts 460; as shown in FIG. 7c.

[0163] Tension applied to the dynamic conduit 408b is thereby transmitted to the conduit attachment via the armoured layer 452, and the strain relief apparatus 407, 456, 458, 460. The inner core 450 is, at least to some degree, isolated from such tensile stress.

[0164] Whilst various exemplary embodiments have been disclosed, it shall be understood that variations, modifications and combinations of the valve and methods disclosed herein disclosed herein may be made without departing from the scope of the appended claims.