SEABED CONNECTION HUB

Abstract

The present invention provides a seabed connection hub (SCH) for guiding a drilling assembly to drill a bore hole and subsequently guiding a deep set tensile anchor into the bore hole. The seabed connection hub (SCH) comprising a body member configured to act as a sea bed anchor. The body member comprises a lower surface configured in use to rest upon, and for at least a portion of the lower surface of the body member to penetrate the sea bed. The body member comprises a guide channel extending therethrough to a first opening provided in the lower surface of the body member. The guide channel is configured to receive and guide a drilling assembly to produce a bore hole. The guide channel is configured to receive and guide a deep set tensile anchor therethrough into the opening of the bore hole. The body member further comprises at least one connector for engaging one or more mooring line termination for an offshore installation. The lower surface of the body member is profiled to extend at an angle to a reference plane defined by the sea bed adjacent the bore hole.

Claims

1. A seabed connection hub (SCH) for guiding a drilling assembly to drill a bore hole and subsequently guiding a deep set tensile anchor into the bore hole, the seabed connection hub (SCH) comprising a body member configured to act as a sea bed anchor, in which the body member comprises a lower surface configured in use to rest upon, and for at least a portion of the lower surface of the body member to penetrate, the sea bed, in which the body member comprises: a guide channel extending therethrough to a first opening provided in the lower surface of the body member, in which the guide channel is configured to receive and guide a drilling assembly to produce a bore hole, and in which the guide channel is configured to receive and guide a deep set tensile anchor therethrough into the opening of the bore hole; and at least one connector for engaging one or more mooring line termination for an offshore installation, in which the lower surface of the body member is profiled to extend at an angle to a reference plane defined by the sea bed adjacent the bore hole.

2. A seabed connection hub (SCH) as claimed in claim 1, further comprising a locking and tensioning mechanism located within the guide channel to engage an elongate tensile member attached to an upper end of the deep set anchor.

3. A seabed connection hub (SCH) as claimed in claim 2, in which the locking and tensioning mechanism comprises a slip type lock mechanism.

4. A seabed connection hub (SCH) as claimed in claim 1, in which the lower surface of the body member is profiled to extend at an angle to a reference plane defined relative to the plane defined by the sea bed adjacent the bore hole.

5. A seabed connection hub (SCH) as claimed in claim 1, in which the body member further comprises a hollow tubular portion in communication with the first opening provided on the lower surface thereof and extends outwardly therefrom to define a portion of the guide channel extending through the hollow tubular portion.

6. A seabed connection hub (SCH) as claimed in claim 5, in which the hollow tubular portion defines a portion of the guide channel having a longitudinal axis which is configured to extend, in use, substantially parallel to the longitudinal axis of the bore hole.

7. A seabed connection hub (SCH) as claimed in claim 1, in which the body member is composed of concrete.

8. A seabed connection hub (SCH) as claimed in claim 5, in which the hollow tubular portion is composed of steel.

9. A seabed connection hub (SCH) as claimed in claim 5, in which the hollow tubular portion is releasably engaged to the lower surface of the body member.

10. A seabed connection hub (SCH) as claimed in claim 5, in which the lower surface of the body member comprises a tapered, conical portion.

11. A seabed connection hub (SCH) as claimed in claim 5, in which the hollow tubular portion comprises a tapered, conical portion adjacent the lower surface of the body member.

12. A seabed connection hub (SCH) as claimed in claim 1, in which the body member comprises an upper surface defining a second opening for receiving a deep set tensile anchor therethrough, and in which the guide channel extends between the first and second openings of the body member.

13. A seabed connection hub (SCH) as claimed in claim 12, in which the first and second openings are axially aligned along an axis which in use is configured to extend substantially parallel to the longitudinal axis of the bore hole.

14. A seabed connection hub (SCH) as claimed in claim 12, in which the second opening has greater dimensions than the first opening.

15. A seabed connection hub (SCH) as claimed in claim 1, further comprising at least one connector for engaging one or more mooring line termination for offshore installations.

16. A seabed connection hub (SCH) as claimed in claim 15, in which the at least one connector are configured for releasable engagement to one or more mooring line termination for offshore installations.

17. A seabed connection hub (SCH) as claimed in claim 15, in which the at least one connector is of fixed orientation relative to the base member.

18. A seabed connection hub (SCH) as claimed in claim 15, in which the at least one connector is a hinged or pivotally connected connector.

19. A seabed connection hub (SCH) as claimed in claim 16, in which the at least one connector is spaced apart from the lower surface of the base member.

20. A seabed connection hub (SCH) as claimed in claim 19, in which the at least one connector is located at or adjacent an upper surface of the base member.

21. A seabed connection hub (SCH) as claimed in claim 1, further comprising at least one resistance member extending outwardly from the body member and configured such that a portion of the at least one resistance member is received within the sea bed.

22. A seabed connection hub (SCH) as claimed in claim 21, in which the body member comprises at least one connector located on a first side thereof for engaging one or more mooring line termination for offshore installations, and in which the body member further comprises at least one resistance member located at or adjacent a second opposed side of the body member.

23. A seabed connection hub (SCH) as claimed in claim 21, in which the at least one resistance member is a plate member.

24. A seabed connection hub (SCH) as claimed in claim 23, in which the resistance member comprises a upper end located adjacent an upper end of the base member, and an opposed lower end which is angular in shape to aid penetration into the sea bed.

25. A method of installing a deep set anchor using a seabed connection hub (SCH) as claimed in claim 1, the method comprising: positioning an seabed connection hub (SCH) as claimed in claim 1 such that the lower surface of the base member rests upon, and at least a portion of the lower surface of the base member penetrates, the sea bed, in which the first opening provided by the lower surface is aligned with an opening for a bore hole; guiding a drilling assembly through the guide channel and first opening of the base member into the opening for a bore hole; operating the drilling assembly to drill the bore hole; inserting deep set tensile anchor on a elongate tensile member through the guide channel and first opening of the body member into the bore hole; and connecting one or more mooring line to the at least one connector, and subsequently tensioning to the one or more mooring line.

26. A method as claimed in claim 25, further comprising inserting the hollow tubular portion into the opening for a bore hole.

27. A method as claimed in claim 25, further comprising embedding at least a portion of at least one resistance member into the sea bed.

28. A method as claimed in claim 25, further comprising operating a locking and tensioning mechanism located within the guide channel to engage the elongate tensile member attached to the deep set tensile anchor.

Description

BRIEF DESCRIPTION OF FIGURES

[0051] FIG. 1 is a schematic illustration of a perspective rear view from above of the seabed connection hub (SCH) according to one embodiment of the present invention;

[0052] FIG. 2 is a schematic illustration from above of the seabed connection hub (SCH) of FIG. 1;

[0053] FIG. 3 is a schematic illustration of a side view of the seabed connection hub (SCH) of FIG. 1;

[0054] FIG. 4 is a schematic illustration of a rear view of the seabed connection hub (SCH) of FIG. 1;

[0055] FIG. 5 is a schematic illustration of a front view of front seabed connection hub (SCH) of FIG. 1; and

[0056] FIG. 6 is a schematic illustration of a perspective view from above of the locking and tensioning mechanism of the seabed connection hub according to one embodiment of the present invention in position on a elongate tensile member of a deep set tensile anchor;

[0057] FIGS. 7A and 7B are schematic illustrations of a side view and a view from above of the seabed connection hub (SCH) according to one embodiment of the present invention;

[0058] FIG. 8 is a schematic illustration of a perspective view from above of the seabed connection hub (SCH) according to a further embodiment of the present invention;

[0059] FIG. 9 is a schematic illustration of a side view of the seabed connection hub (SCH) of FIG. 8;

[0060] FIG. 10 is a schematic illustration of a view from above of the seabed connection hub (SCH) of FIG. 8;

[0061] FIG. 11 is schematic illustration of a perspective rear view of the seabed connection hub (SCH) of FIG. 8;

[0062] FIG. 12 is a schematic illustration of a cross-sectional side view of the seabed connection hub (SCH) of FIG. 8;

[0063] FIG. 13 is a schematic illustration of a cross-sectional side view of a seabed connection hub (SCH) according to a further embodiment of the present invention, in which the hub comprises three connectors;

[0064] FIG. 14 is a schematic illustration of a perspective view from above of the seabed connection hub (SCH) of FIG. 13;

[0065] FIG. 15 is a schematic illustration of a view from above of a of the seabed connection hub (SCH) of FIG. 13;

[0066] FIG. 16 is a schematic illustration of a perspective view from above of the body member portion of the seabed connection hub (SCH) of FIG. 13;

[0067] FIGS. 17A to 17D are schematic illustrations of the locking and tensioning mechanism of the seabed connection hub (SCH) according to one embodiment of the present invention;

[0068] FIG. 18 is a schematic illustration of the locking and tensioning mechanism of the seabed connection hub (SCH) according to a further embodiment of the present invention;

[0069] FIG. 19 is a schematic illustration of the seabed connection hub secured to the seabed and connected to a mooring line termination; and

[0070] FIG. 20 is a schematic illustration of the seabed connection hub (SCH) according to one embodiment of the present invention in communication with a deep set tensile anchor.

DETAILED DESCRIPTION

[0071] With reference to the Figures, the seabed connection hub (SCH) 1, 1, 101, 101 comprises a body member 2, 2, 102, 102 composed of concrete, or other suitably dense material, configured to act as a sea bed anchor. The body member 2, 2, 102, 102 comprises a lower surface 3, 3, 103, 103 configured in use to rest upon, and for at least a portion of the lower surface 3, 103, 103 of the body member 2, 2, 102, 102 to penetrate, the sea bed. The lower surface 3, 3, 103, 103 of the body member 2, 2, 102, 102 provides a first opening (not shown). The body member 2, 2, 102, 102 further comprises an opposed upper surface 4, 4, 104, 104 defining a second opening 5, 5, 105, 105. The second opening 5, 5, 105, 105 has greater dimensions than the first opening (not shown). It is however to be understood that the first (not shown) and second openings 5, 5, 105, 105 may have the same dimensions. A guide channel 6, 6, 106, 106 for receiving a deep set anchor therethrough, extends between the first (not shown) and second openings 5, 5, 105, 105 of the body member 2, 2, 102, 102. The guide channel 6, 6, 106, 106 may taper inwardly between the first (not shown) and second openings 5, 5, 105, 105 of the body member 2, 2, 102, 102.

[0072] It is to be appreciated that although the guide channel 6, 6, 106, 106 in the illustrated embodiments extends between the upper and lower surfaces 3, 3, 103, 103, 4, 4, 104, 104 of the body member 2, 2, 102, 102 that the guide channel 6, 6, 106, 106 may extend between any suitable surface and the lower surface 3, 3, 103, 103 of the body member 2, 2, 102, 102.

[0073] In the illustrated embodiment, the first (not shown) and second openings 5, 5, 105, 105 are axially aligned such that the guide channel 6, 6, 106, 106 extending therebetween is substantially linear in shape. It is however to be understood that the guide channel 6, 6, 106, 10 may have any suitable configuration depending on the requirements for the seabed connection hub (SCH), for example the guide channel 6, 6, 106, 106 may comprise one or more curved portions and/or one or more diverging portions.

[0074] The lower surface 3, 3, 103, 103 of the body member 2, 2, 102, 102 once embedded into the sea bed, may provide resistance to the lateral vector force from the one or more mooring line terminations. In the illustrated embodiment, the lower surface 3, 3, 103, 103 of the base member 2, 2, 102, 102 is substantially conical in shape. The conical lower surface 3, 3, 103, 103 tapers inwardly in a direction extending away from the base member 2, 2, 102, 102 and towards the bore hole. It is however to be understood that the lower surface 3, 3, 103, 103 may have any suitable profile for providing resistance to the lateral vector force. For example, the lower surface 3, 3, 103, 103 may be substantially planar and/or may extend at an angle to a reference plane defined relative to the plane defined by the sea bed adjacent the bore hole.

[0075] The seabed connection hub serves in use as a resistance point accommodating the change in direction of the tensile loading from vertical to lateral. The shape and/or dimensions of the body member 2, 2, 102, 102 may be varied with a view to optimising the bending stresses and the transfer of the lateral component of mooring lines loads into the soil adjacent the body member 2, 2 102, 102 and bore hole.

[0076] The body member 2, 2, 102, 102 further comprises a hollow tubular portion 7, 7, 107, 107 composed of steel, positioned adjacent and in communication with the first opening (not shown) provided on the lower surface 3, 3 #, 103, 103 thereof. The hollow tubular portion 7, 7, 107, 107 extends outwardly from the lower surface 3, 3, 103, 103 of the body portion 2, 2, 102, 102 and a portion of the guide channel 6, 6, 106, 106 extends through the hollow tubular portion 7, 7, 107, 107.

[0077] In the illustrated embodiments, the hollow tubular portion 7, 7, 107, 107 defines a portion of the guide channel 6, 6, 106, 106 having a longitudinal axis which extends substantially perpendicular to a reference plane defined by the sea bed. The hollow tubular portion 7, 7, 107, 107 defines a portion of the guide channel 6, 6, 106, 106 having a longitudinal axis which is configured to extend, in use, substantially parallel to the longitudinal axis of the bore hole.

[0078] In the illustrated embodiments, the hollow tubular portion 7, 7, 107, 107 forms an integral component of the seabed connection hub (SCH) 1, 1, 101, 101. It is however to be understood that the hollow tubular portion 7, 7, 107, 107 may be releasably engaged to the lower surface 3, 3, 103, 103 of the body member 2, 2, 102, 102. The hub 1, 1, 101, 101 may comprise a plurality of hollow tubular portions 7, 7, 107, 107 having different shapes and/or dimensions which may be selected depending on the requirements for installation into a bore hole.

[0079] The hollow tubular portion 7, 7, 107, 107 comprises a first end 8, 108, 108 located adjacent the lower surface 3, 103, 103 of the body member 2, 102, 102 and an opposed, tapered second end 9, 109, 109. The hollow tubular portion 7, 107, 107 is substantially cylindrical in shape with a tapered second end 9, 109, 109.

[0080] The hollow tubular portion 7, 107, 107 is configured to be driven into the sea bed to be located within an upper section of the bore hole. The hollow tubular portion 7, 7, 107, 107 is configured to provide support to the upper section of the bore hole, i.e. to prevent collapse of the surrounding soil into the bore hole, prior to and during subsequent drilling of the bore hole. The hollow tubular portion 7, 7, 107, 107 therefore helps to stabilise the soil, for example soft soil structures, adjacent the upper section of the bore hole.

[0081] The body member 2, 2, 102, 102 comprises a first side 10, 10, 110, 110 configured in use to be positioned facing the corresponding mooring line(s), and offshore installation, and an opposed second side 11, 11, 111, 111. The first side 10, 10, 110, 110 of the body member 2, 2, 102, 102 comprises a connector 12, 12, 112, 112 for engaging, preferably releasably engaging, a termination of a mooring line termination for an offshore installation. It is to be understood that the body member 2, 102 may comprise any suitable number of connectors 12, 12, 112, 112 in any suitable location depending on the requirements for the base 1, 1, 101, 101. By providing releasable engagement with the connector 12, 12, 112, 112 the base 1, 1, 101, 101 may be reused for connection to further mooring line terminations.

[0082] In the illustrated embodiment of FIGS. 1 to 5 and FIGS. 7A-B, the connector 12, 12 is of fixed orientation relative to the base member 2, 2 at a predetermined angle to align with an axis defined by the mooring line. The connector 12, 12 extends an at angle to the longitudinal axis of the guide channel 6, 6 and to the longitudinal axis of the bore hole. It is however to be understood, as shown in FIGS. 8 to 16, that the orientation of the one or more connectors 112, 112 may be independently adjustable, for example hinged or pivotally connected to the body member 102, 102, to align with an axis defined by the mooring line, depending on the requirements for the installation.

[0083] The connector 12, 12, 112, 112 is located adjacent the upper surface 4, 4, 104, 104 of the body member 2, 102, 102 such that the connector 12, 12, 112, 112 is located, in use, at a height about the sea bed to prevent the engaged mooring line from interacting with the seabed soils.

[0084] The seabed connection hub (SCH) 1, 1, 101 in the illustrated embodiments of FIGS. 1 to 5, 7A, 7B and FIGS. 8 to 13, further comprises one or more resistance members 13, 13, 113. As shown in the illustrated embodiments, the resistance members 13, 13, 113 are in the form of a plate located adjacent the second side 11, 11, 111 and extending outwardly from the body member 2, 2, 102. The resistance member 13, 13, 113 is configured to be received within the soil to increase resistance once embedded in the soil.

[0085] In the illustrated embodiments of FIGS. 1 to 5 and FIGS. 7A and 7B, the seabed connection hub (SCH) 1, 1 comprises three resistance members 13, 13 located adjacent the second side 11. 11 of the body member 2, 2. It is however to be understood that the hub 1,1 may comprise any suitable numbers of resistance members 13, 13 at any suitable location on the body member 2, 2. As shown in the illustrated embodiment of FIGS. 8 to 13, the hub 101 comprises a single resistance member 113 located adjacent the second side 111 of the body member 102. It is to be understood that the hub may comprise a pair of resistance members or more than three resistance members, depending on the particular requirements for the hub.

[0086] The resistance members 13, 13, 113 are steel, plate members each comprising an upper end 14, 14, 114 substantially aligned with an upper end 4, 4, 104 of the body member 2, 2, 102 and an opposed lower end 15, 15, 115 which is angular in shape to aid penetration into the sea bed.

[0087] The lower end 15, 15, 115 of the resistance members 13, 13, 113 extend from the lower surface 3, 3, 103 towards the upper surface 4, 4, 104 of the body member 2, 2, 102. The lower end 15, 15, 115 of the resistance members 13, 13, 113 extend beyond the lower surface 3, 3, 103 of the body member 2, 2, 102 such that the lower end 15, 15, 115 of the resistance members 13,13, 113 are embedded into the sea bed during installation and thus assist in stabilisation and ensuring verticality of the hub 1, 1, 101 when landed on seabed.

[0088] In the illustrated embodiments of FIGS. 1 to 5 and FIGS. 8 to 13, the body 16, 116 of each resistance member 13, 113 defines a plane extending substantially parallel to the longitudinal axis defined by the bore hole. It is however to be understood that the body 16, 116 of each resistance member 13, 113 may define a plane extending at an angle to the longitudinal axis defined by the bore hole. As shown in the illustrated embodiment of FIGS. 7A and 7B, the resistance member 13 may comprise a first portion 13a which defines a plane extending substantially parallel to the longitudinal axis defined by the bore hole and a second portion 13b which defines a plane extending at an angle to the longitudinal axis of the bore hole. The second portion 13b in the illustrated embodiment can be seen to extend substantially perpendicular to the angle defined by the connector 12. The portion 13a of the resistance member 13 which defines a plane extending substantially parallel to the longitudinal axis aids penetration of the resistance member into the seabed. The portion 13b of the resistance member 13 which defines a plane extending substantially perpendicular to the axis of the connector 12 helps to provide resistance to the lateral component of mooring lines loads.

[0089] With reference to FIGS. 1 to 5, each resistance member 13 extends substantially parallel to the other resistance members 13. The resistance members 13 are provided as a parallel array of resistance members 13. The resistance members 13 are spaced apart from each other and adjoined to each other by strengthening struts 17. It is however to be understood that the entire assembly may be constructed of steel plate or other suitable material. As shown in the illustrated embodiment of FIGS. 8 to 13, the resistance member 113 is secured to the body member 102 by struts 117. The struts 117 and resistance member 113 are formed by a continuous steel plate.

[0090] It is to be understood that the seabed connection hub 101 may not include resistance members as shown in FIGS. 14 to 16.

[0091] The seabed connection hub (SCH) 1, 1, 101, 101 further comprises a locking and tensioning mechanism 20, 120 as shown in FIGS. 6 and 17A-17D. The locking and tensioning mechanism 20, 120 is located within the guide channel 6, 6, 106, 106 of the hub 1, 1, 101, 101 to engage a elongate tensile member 21, 121 attached to an upper end of the deep set anchor (not shown) during installation. The locking and tensioning mechanism 20, 120 may be located at any suitable location within the guide channel 6, 106, 106. The locking and tensioning mechanism 20, 120 comprises a plurality of circumferentially spaced apart grip portions 22, 122 mounted at a first end thereof. The locking and tensioning mechanism 20, 120 comprises an attachment feature 23, 123 located at a second end thereof and secured to the hub 1, 1, 101, 101. The locking and tensioning mechanism 20, 120 comprises a hydraulic actuator 24, 124 extending between the grip portions 22, 122 and the attachment feature 23, 123.

[0092] In use, the seabed connection hub (SCH) 1, 1, 101, 101 as herein described is positioned on the sea bed such that the lower surface 3, 3, 103, 103 of the body member 2, 2, 102, 102 rests upon, and at least a portion of the lower surface 3, 3, 103, 103 of the body member 2, 2, 102, 102 penetrates, the sea bed.

[0093] The hollow tubular portion 7, 7, 107, 107 provides an opening through which a bore hole may be drilled or otherwise established. Once the bore hole is established, the hollow tubular portion 7, 7, 107, 107 supports and stabilises the soft soil structure adjacent the opening of the bore hole, preventing collapse of the surrounding soils. The conical lower surface 3, 3, 103, 103 of the body member 2, 2, 102, 102 and also, in some embodiments, the lower edge 15, 115, 115 of the resistance member(s) 13, 113, 113 are embedded into the sea bed.

[0094] A drilling assembly is inserted through the second opening 5, 5, 105, 105 provided by the upper surface 4, 4, 104, 104 of the base member 2, 2, 102, 102 into the guide channel 6, 6, 106, 106. The drilling assembly is guided through the guide channel 6, 6, 106, 106 and the hollow tubular portion 7, 7, 107, 107 into the opening of the bore hole.

[0095] The drilling assembly is operated to drill the bore hole of required depth and the drilling assembly is subsequently removed from the bore hole and the hub 1, 101, 101.

[0096] A deep set tensile anchor on a elongate tensile member 21, 121 is inserted through the second opening 5, 5, 105, 105 provided by the upper surface 4, 4, 104, 104 of the body member 2, 2, 102, 102 into the guide channel 6, 6, 106, 106. The deep set tensile anchor is guided through the guide channel 6, 6, 106, 106 and the hollow tubular portion 7, 7, 107, 107 into the bore hole.

[0097] The deep set tensile anchor 125 is inserted into the bore hole 126 (as shown in FIG. 20). During insertion the locking and tensioning mechanism 20, 120 (as shown in FIGS. 17A-D and 18) is operated such that the grip portions 22, 122 engage the elongate tensile member 21, 121 attached to the deep set tensile anchor at a predetermined located. The hydraulic actuator 24, 124 acts on the attachment feature 23, 123 which exerts a downward force onto the hub 1, 1, 101, 101 driving the hub 1, 1, 101, 101 into the seabed to provide a more secure seabed anchor for the vertical forces of the mooring line.

[0098] A mooring line for an offshore installation is connected to the connector 12, 12, 112, 112.

[0099] As shown in FIG. 18 the mooring line transmits tensile loading to the subsea connection hub 1 which provides a resistance point accommodating the change in direction of the tensile loading from vertical to lateral.

[0100] The resistance member(s) 13, 113 embedded in the soil, act to resist lateral forces from the mooring line as shown in FIG. 18. Furthermore, the conical lower surface 3, 3, 103, 103 of the body member 2, 2, 102, 102 is also embedded within the soil surrounding the bore hole opening and also transfers the lateral forces of the mooring line into the surrounding soil.

[0101] It is to be understood that the seabed connection hub (SCH) 1, 1, 101, 101 may comprise a lower surface having a different profile to the one illustrated in the attached Figures. For example, the lower surface may be angled or profiled to enable embedding within the soil surrounding the bore hole. The seabed connection hub (SCH) may comprise any suitable number of fixed, or adjustable (for example hinged or pivotable) connectors, at any suitable location on the body member. The seabed connection hub (SCH) 1, 1, 101, 101 may not include an elongate tensile member. The seabed connection hub (SCH) 1, 1, 101, 101 may comprise one or more engagement features for releasably engagement to cooperative engagement features on an elongate tensile member. The elongate tensile member may have any suitable profile and/or dimensions. The seabed connection hub (SCH) may comprise any suitable number of resistance members having any suitable shape and dimensions. The guide channel of the seabed connection hub (SCH) may extend through any suitable surfaces of the body member and is not limited to extending between the upper and lower surfaces thereof.

[0102] It is to be understood that the hub 1, 1, 101, 101 may be designed to be substantially or completely embedded to a depth in the seabed soils when tension is applied to the connected mooring line such that the transition base acts as an anchor or resistance device which is secondary to the deep set mooring pile and thereby reduces the tension applied at the deep set anchor pile.