Stabilization systems and assemblies for deepwater offshore use

Abstract

A stabilization assembly for use in deep water is provided, the assembly comprising a telescoping spar for anchoring within a moonpool of a floating support vessel, the anchoring mechanism including a gimbal-type joint secured within the moonpool, the spar being suspended by the gimbal-type joint during use to allow relative movement between the vessel and the spar.

Description

[Technical Field]

[0001] The present invention relates to stabilization systems and assemblies for deep offshore water use, and more particularly to deep offshore water stabilization systems and assemblies for cranes, platforms, wind turbines, and the like. [Background technology]

[0002] With increasing decommissioning of oil and gas facilities to tackle climate change and the offshore wind industry rapidly expanding, heavy lifting operations in deep offshore waters are in higher demand than ever before.

[0003] There is a movement within the wind industry to install larger, more economical equipment offshore in deeper waters to take advantage of higher, more consistent, and cleaner air currents. The next generation of wind turbines could rival significant tall structures in size. For example, 15 MW turbines could approach 265 m in height.

[0004] Lifting heavy loads in deep offshore waters has always been a challenge, requiring specialized machinery that is extremely expensive. Historically, the job has required periods of calm weather to work efficiently, often resulting in project delays and budget overruns due to unreliable weather conditions.

[0005] However, with the recent proliferation of offshore wind power, offshore lifting operations have become a common occurrence that current solutions struggle to cope with.

[0006] Current vertical motion compensation cranes are limited by size. Traditional large cranes are limited by sea and weather conditions. Current jack-up cranes are limited by water depth. Current semi-submersible cranes are limited by cost (typically around $1B per vessel). Summary of the Invention [Problem to be solved by the invention]

[0007] SUMMARY OF THE INVENTION The present invention aims to provide a stabilization system and assembly for deep water offshore crane use that does not have the above-mentioned limitations.

[0008] Specifically, the present invention is directed to utilizing a more versatile spar-type platform suitable for transport to and use in deep water lifting operations.

[0009] Spar-type platforms are recognized for providing high stability in all sea conditions. However, due to their deep draft, spar-type platforms can only be fully deployed in deep water. Therefore, when used, the spar must be floated sideways to the deployment site and then returned to vertical. The considerable length of the spar makes transportability and deployment a challenge.

[0010] SUMMARY OF THE INVENTION The present invention aims to provide an improved telescoping spar assembly for increased versatility and transportability utilizing conventional ships or oceangoing barges.

[0011] A further object of the present invention is to provide a more versatile stabilization mechanism that is not limited by sea conditions and is hardly affected by sea conditions.

[0012] In particular, the present invention aims to provide an improved deep water stabilisation assembly which allows pivoting between the support vessel and the spar during use, so that industrial equipment supported by the spar is less affected by changing sea conditions.

[0013] The industrial equipment may be, for example, but is not limited to, a platform, a crane, or a wind turbine (eg, capable of offshore equipment maintenance). [Means for solving the problem]

[0014] According to one aspect of the present invention, there is provided a stabilisation assembly for use in deep water, the assembly comprising a telescoping spar for anchoring within a moonpool of a floating support vessel, the anchoring mechanism including a gimbaled joint secured within the moonpool, the spar being suspended by the gimbaled joint in use to allow relative movement between the vessel and the spar.

[0015] Preferably the spar supports a crane.

[0016] Alternatively or additionally, the spar supports a wind turbine.

[0017] Alternatively or additionally, the spar supports the platform.

[0018] Preferably, the spar is constructed with at least two tubular sleeve sections, one slidable within the other, thereby allowing the spar to telescopically extend or retract.

[0019] Preferably, the spar is constructed from three tubular sections.

[0020] Preferably, each section includes a helical strake on its outer surface.

[0021] Preferably, the spar includes a collapsible air bladder in the upper section, which allows the buoyancy of the spar to be adjusted.

[0022] Preferably, the lower section includes a ballast secured to the lower section.

[0023] Preferably, the spar includes an internal access ladder and platform that automatically deploys during extension of the spar.

[0024] Preferably, the gimbal joint comprises inner and outer concentric rings having axes of rotation at 90 degrees relative to each other.

[0025] Preferably, the inner ring is connected to the spar via two opposing axes of rotation at 180 degrees to each other and to the outer ring via another two opposing axes of rotation at 90 degrees to the spar connections.

[0026] Preferably, the outer ring is split longitudinally into two halves which are pivotally connected at both ends and share a common pinion with the inner ring.

[0027] Preferably, the end of each half ring distal from the pivot connection has a counterweight secured to it.

[0028] Preferably, each counterweight is secured to the outer ring via a vertically oriented shaft that is fixed to the inner wall of the moonpool and forms a fulcrum, and an arm that is supported on a bearing point.

[0029] Preferably, the counterweight is housed in a recess provided in the deck and hull of the ship.

[0030] Preferably, the assembly further comprises means for locking the gimbal ring and counterweight in place.

[0031] According to a second aspect of the present invention there is provided a floating vessel having at least two moonpools, each moonpool including a stabilising assembly according to the first aspect.

[0032] According to a third aspect of the present invention, there is provided a structure for location offshore in deep water, the structure having a telescoping spar secured thereto for providing stability to the structure when extended.

[0033] Structure means an industrial installation located offshore in deep waters, for example a wind turbine or a platform. The platform may be a service platform for maintenance of the wind turbine by authorized personnel.

[0034] According to a fourth aspect of the present invention there is provided a floating vessel for transporting a structure of the fourth aspect to a deep water offshore location, the floating vessel including a gimbaled joint of any of the previous aspects fixed within a vessel framework, the gimbaled joint having means for receiving and suspending the telescoping spar with the spar fully retracted during transport.

[0035] According to a fifth aspect of the present invention, there is provided a method of stabilising a wind turbine in deep offshore waters, the wind turbine having the stabilisation assembly of any of the previous aspects, the method comprising the steps of: retracting the spar in a hull of a floating vessel so that the ballast is flush with the bottom of the vessel, locking the gimbaled joint and counterweight in place in a moonpool of the floating vessel, transporting the wind turbine to a deep offshore location, unlocking the gimbaled joint and counterweight to allow pivoting, and fully extending the spar downwards to stabilise the wind turbine.

[0036] According to a sixth aspect of the present invention, there is provided a method of stabilizing a wind turbine in deep offshore waters, the wind turbine having the stabilization assembly of any of the preceding aspects, the method comprising using the floating vessel of the fifth aspect to stabilise a wind turbine in deep offshore waters, the wind turbine having the stabilisation assembly of any of the preceding aspects, the method comprising the steps of: once the spar is fully retracted, disengaging the gimbaled joint to receive the wind turbine spar, clamping the gimbaled joint around the spar, locking the gimbaled joint and counterweight in place to prevent pivoting, transporting the wind turbine to an offshore location in deep waters, unlocking the gimbaled joint and counterweight to allow pivoting, fully extending the spar downward to stabilize the wind turbine, and disengaging the gimbaled joint to release the wind turbine spar. [Brief explanation of the drawings]

[0037] At least one embodiment of the present invention will now be described with reference to the accompanying drawings. [Figure 1] 1 illustrates a stabilization assembly for a crane constructed in accordance with a first embodiment of the present invention. [Figure 2] 2 shows the assembly of FIG. 1 with the spars deployed. [Figure 3] Shows the deployment of the spar. [Figure 4] FIG. 2 is a plan cross-sectional view of the assembly. [Figure 5] FIG. 2 is a schematic cross-sectional side view of the assembly. [Figure 6] 1 illustrates a crane stabilization assembly constructed in accordance with a second embodiment of the present invention. [Figure 7] 7 shows the assembly of FIG. 6 with the spars deployed. [Figure 8] 10 illustrates a crane stabilization assembly constructed in accordance with a third embodiment of the present invention. [Figure 9] 10 illustrates a crane stabilization assembly constructed in accordance with a fourth embodiment of the present invention. [Figure 10] 10 illustrates a crane stabilization assembly constructed in accordance with a fifth embodiment of the present invention. [Figure 11] FIG. 11 is a plan view of the assembly of FIG. 10. [Figure 12] 1 shows wind turbines deployed offshore.

[0038] DETAILED DESCRIPTION OF THE INVENTION

[0039] 1 shows a schematic diagram of a crane stabilization assembly for use offshore in deep waters, the assembly comprising a floating industrial support vessel 2, such as an ocean-going vessel.

[0040] Vessel 2 is configured with a moonpool 4. Moonpools are a common feature of industrial deep-sea vessels such as offshore drilling platforms, diving support vessels, and the like, and are typically openings in the floor or base of the vessel that provide access to water to allow technicians to lower tools or equipment into the sea.

[0041] Vessel 2 carries spar 6. Spars are large diameter, vertical, buoyant cylinders with deep draft and stabilized ballast that are commonly used to provide stable foundations for offshore equipment, making the structure less responsive to wind, waves, and currents.

[0042] The spar 6 is suspended and held within the confines of the ship in and through the moonpool 4. A structure of industrial work equipment, for example a crane 8, is fixed to or near the top of the spar 6. As will be described below, the industrial equipment may be, for example, a platform or a wind turbine.

[0043] The spar 6 is telescopic and can be deployed into a downwardly extended position, thereby increasing the draft of the spar 6 and providing a stable platform independent of the vessel 2 when the vessel 2 reaches a location in deep water.

[0044] FIG. 2 shows the spar 6 in an extended and deployed state.

[0045] Because spar 6 is telescoping, vessel 2 can navigate shallow waters carrying spar 6 in a stowed state until the vessel reaches deeper waters where spar 6 can be deployed.

[0046] FIG. 3 shows the telescoping mechanism of the spar 6. For simplicity, the crane is not shown. The spar 6 is constructed from three tubular sleeve sections 10 of decreasing diameter, with a third end section 10C slidable within a second middle section 10B, and a second section slidable within a first upper section 10A. Any number of sections 10 may be used to vary the possible draft of the spar 6.

[0047] Section 10 may include helical strakes to improve hydrodynamic stability.

[0048] Alternatively, the spar may be constructed from at least one tubular section and one truss section and include a heave plate.

[0049] By inflating a collapsible air bladder located in the upper section of spar 6, the ballast / buoyancy can be adjusted to compensate for the crane's lifting load.

[0050] A permanent ballast 12 is secured to the distal end of the third sleeve 10C to stabilize the tip of the spar 6, which is the deepest point below the water surface.

[0051] As shown most clearly in FIG. 3B, the interior access ladder 14 and platform 16 may be pre-installed to self-deploy as the spar 6 extends.

[0052] Figure 4 is a plan cross-sectional view of the securing mechanism that suspends spar 6 within moonpool 4 of vessel 2. The mechanism secures spar 6 so that vessel 2 can pivot about spar 6 when weather conditions change and the mechanism is deployed.

[0053] The suspension mechanism consists of a double axis gimbal type joint / universal joint arrangement consisting of inner and outer concentric rings 18, 20 with their axes of rotation at 90° angles to each other.

[0054] The inner ring 18 is connected to the spar 6 via two opposing axes of rotation at 180° to each other and to the outer ring 20 via another two opposing axes of rotation at 90° to the spar connections.

[0055] As can be seen in FIG. 5, the outer ring 20 is split longitudinally into two halves 22 which are pivotally connected at both ends and share a common pinion 24 with the inner ring 18 .

[0056] The end of each half ring 22 distal from the pivot link 26 carries a counterweight 28 which is fixed to the end of each half ring 22 via an arm 30 supported on a vertically oriented shaft and bearing point 32 fixed to the inner wall of the moonpool 4 and forming a fulcrum.

[0057] The counterweight 28 extends to be received within a recess 34 provided in the deck and hull of the vessel 2 .

[0058] The gimbal mechanism and counterweight compensate for the heave, pitch and roll experienced by the vessel 2 when the spar 6 is deployed offshore in deep waters.

[0059] The gimbal rings 18, 20 and counterweight 28 are locked in place during transport, at which time the gimbal joint and counterweight 28 are locked by locking pins and the spar 6 is telescopically retracted into the crane tower to the point where the top of the ballast 12 is flush with the bottom of the ship 2.

[0060] If desired, further compensation can be added to the crane by adding a telescoping counterweight to counter the bow delta, a winch to compensate for heave, or a spring-loaded heave compensator on top of the sling.

[0061] Once in position, the pin locking the gimbal joint is removed and the spar 6 is deployed before the crane's bow sail is raised. Once the spar 6 is fully extended, the ship 2 can be moved independently of the spar 6. The counterweight 28 is typically selected to have a weight equal to the entire crane structure, excluding the crane's lifting load.

[0062] The pitch, sway and yaw movements are controlled by actuating the thrusters of the vessel 2.

[0063] 6 and 7 show a further embodiment of the present invention, providing a vessel 36 with an extensive deck area and two moonpools 38. The deck area is divided into two platform sections 40, each equipped with a motion compensation mechanism as described above.

[0064] Figure 6 shows the ship 36 adjacent to a port in shallow water. In this example, the spars supporting each platform 40 can be seen fully retracted. The gimbaled joints 42 and counterweights 44 are locked in place. The ship 36 is now ready to go out to sea.

[0065] 7 shows the vessel 36 in its deployed position in deep water, with both platform spars 46 deployed to stabilize the platform decks independently of vessel 36 motion.

[0066] Figure 8 shows a further embodiment of the invention, providing a vessel 36 including a crane spar 6 as described above on one part of the deck area and a platform 40 on the other. In the figure, the crane spar 6 and the platform spar 46 are deployed for stabilising the crane 8 and the platform 40 respectively.

[0067] FIG. 9 shows a further embodiment of the invention, providing a vessel 2 with a single moonpool 4 and a crane spar 6 which also supports a platform 40 .

[0068] 10 and 11 show a vessel 48 capable of carrying a wind turbine 50 for transport to a deep water offshore location. The wind turbine has a telescoping spar 6 as previously described to provide stabilization of the wind turbine 50 at the deep water location. When the vessel 48 is loaded in port, the spar 6 is retracted.

[0069] In this case, the gimbal mechanism supporting the spar 6 is fixed to the side of the ship 48 and mounted within a framework 52 extending from the side of the ship 48. By providing a further gimbal mechanism and framework 52 on another side of the ship 48, two wind turbines 50 can be loaded and transported simultaneously. Depending on the size of the ship 48, any number of wind turbines 50 may be loaded and transported on the ship 48 at the same time.

[0070] The spar 6 of each wind turbine is raised and lowered into a gimbal arrangement using a crane 54 adjacent to the port.

[0071] As can be seen in Figure 11, each gimbaled joint is separable at one point to accommodate the retracted spars 6. Once in position, the gimbaled joint is closed and secured with a gimbal clamp, locking the gimbal mechanism and counterweight in place for transport.

[0072] Upon arrival at the deep water location, each gimbaled joint is unlocked in turn and the spars 6 are deployed. Weight shifts are simultaneously compensated for using the ballast tanks of the vessel 48. Once the spars 6 are fully deployed, each wind turbine 50 is supported and the anchors are secured, the gimbal clamps are released and the vessel 48 can move away using its side boosters.

[0073] FIG. 12 shows a fully supported wind turbine 50 with the spars 6 of the wind turbine 50 deployed. [Explanation of symbols]

[0074] 2 ships 4. Moon Pool 6 Spar 8 Crane 10 Sections 10A Upper Section 10B Mid Section 10C End Section 12 Bottom load 14 Interior Access Ladder 16 Platform 18 Inner Ring 20 outer ring 22 half 24 Pinion 26 Pivot connection 28 Counterweight 30 Arm 32 bearing points 34 Recess 36 ship 38 Moon Pool 40 Platform 42 Gimbal type joint 44 Counterweight 46 Platform Spar 48 Ship 50 wind turbines 52 Frame 54 Crane

Claims

1. 1. A stabilization assembly for use in deep water, comprising: the assembly comprising a telescoping spar for anchoring within a moonpool of a floating support vessel; a fixing mechanism including a gimbal-type joint fixed within the moonpool, the spar being suspended by the gimbal-type joint in use to allow relative movement between the vessel and the spar.

2. The stabilizing assembly of claim 1 , wherein the spar supports a crane.

3. The stabilization assembly of claim 1 , wherein the spar supports a wind turbine.

4. The stabilization assembly of claim 1 , wherein the spar supports a platform.

5. 5. A stabilization assembly according to any one of claims 1 to 4, wherein the spar is configured with at least two tubular sleeve sections, one sleeve section being slidable within the other sleeve section, thereby allowing the spar to telescopically extend or retract.

6. 6. The stabilization assembly of claim 5, wherein the spar is constructed from three tubular sections.

7. 7. A stabilising assembly according to claim 5 or 6, characterized in that each section includes a helical strake on its outer surface.

8. 8. A stabilising assembly according to any one of claims 5 to 7, wherein the spar includes a collapsible air bladder in the upper section, which allows the buoyancy of the spar to be adjusted.

9. 9. A stabilising assembly according to any one of claims 5 to 8, characterized in that the lower section includes a bottom ballast secured to said lower section.

10. 10. A stabilising assembly according to any one of claims 5 to 9, wherein the spar includes an internal access ladder and platform which automatically deploys during extension of the spar.

11. 11. A stabilization assembly according to any preceding claim, wherein the gimbal-type joint comprises inner and outer concentric rings having axes of rotation at 90 degrees relative to each other.

12. 12. The stabilization assembly of claim 11, wherein the inner ring is connected to the spars via two opposing axes of rotation at 180 degrees relative to each other and to the outer ring via another two opposing axes of rotation at 90 degrees relative to the spar connections.

13. 13. The stabilized assembly of claim 12, wherein the outer ring is split longitudinally into two halves, the two halves pivotally connected at opposite ends and sharing a common pinion with the inner ring.

14. 14. The stabilization assembly of claim 13, wherein the end of each half-ring distal to the pivot connection has a counterweight secured thereto.

15. 15. A stabilizing assembly according to claim 14, characterized in that each counterweight is fixed to the outer ring via a vertically oriented shaft and an arm supported on a bearing point fixed to the inner wall of the moonpool and forming a fulcrum.

16. 16. A stabilizing assembly according to claim 15, wherein the counterweight is housed in a recess provided in the deck and hull of the vessel.

17. 17. A stabilization assembly according to any one of claims 14 to 16, further comprising means for locking the gimbal ring and counterweight in place.

18. A floating vessel having at least two moonpools, A floating vessel, characterized in that each moonpool comprises a stabilising assembly according to any one of claims 1 to 17.

19. A structure located offshore in deep water, comprising:

1. A structure characterized in that said structure has telescoping spars secured to said structure to provide stability to said structure when extended.

20. 20. A floating vessel for transporting the structure of claim 19 to a deep water offshore location, comprising: The floating vessel includes a gimbal-type joint according to any one of claims 1 to 19 fixed within the vessel's framework; 10. A floating vessel, comprising: a gimbal-type joint having means for receiving and suspending said telescopic spar when said spar is fully retracted during transport.

21. 1. A method of stabilizing a wind turbine in deep offshore waters, comprising: The wind turbine comprises a stabilisation assembly according to any one of claims 14 to 17, The method comprises: contracting the spar so that the ballast is flush with the bottom of the hull of the floating vessel; locking the gimbaled joint and counterweight in place within the moonpool of the floating vessel; transporting the wind turbine to the deep water offshore location; unlocking the gimbal joint and counterweight to allow pivoting; extending the spar fully downward to stabilize the wind turbine; A method comprising:

22. 21. A method of stabilizing a wind turbine in deep offshore waters using the floating vessel of claim 20, comprising: The wind turbine comprises a stabilisation assembly according to any one of claims 14 to 17, The method comprises: once the spar is fully retracted, disengaging the gimbal-type joint to receive the spar of the wind turbine; clamping the gimbal-type joint around the spar; locking the gimbal joint and counterweight in place to prevent any pivoting; transporting the wind turbine to the deep water offshore location; unlocking the gimbal joint and counterweight to allow pivoting; extending the spar fully downward to stabilize the wind turbine; separating the gimbaled joint to release the spar of the wind turbine; A method comprising:

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