Stabilization system and assembly for offshore deepwater

Abstract

A stabilization assembly for deep water. The assembly includes a telescopic mast for securing within a moon pool of a floating support vessel. The securing mechanism includes a gimbal secured within the moon pool by which the mast is suspended to allow movement of the hull relative to the mast during use.

Description

Technical Field

[0001] The present invention relates to a stabilization system and assembly for offshore deepwater applications. More particularly, the present invention relates to a stabilization system and assembly for offshore deepwater cranes, platforms, wind turbines, or similar applications. Background Art

[0002] With more and more oil and gas facilities being decommissioned and the offshore wind industry rapidly expanding in response to climate change, the demand for heavy lift operations in deepwater has never been greater.

[0003] The wind power industry is driving the development of larger, more economical offshore deepwater turbines to capitalize on higher, more stable, and cleaner air currents. Future generations of wind turbines are expected to rival the size of famous high-rise landmarks. For example, a 15-megawatt wind turbine would be nearly 265 meters tall.

[0004] Heavy lifting in deep offshore waters has always been a challenge, requiring specialized machinery at significant expense. Historically, operations have required calm weather windows to operate efficiently, often leading to project delays and overruns due to unstable weather conditions.

[0005] However, the rise of offshore wind energy in recent years has made offshore lifting operations the norm, and current solutions are struggling to cope.

[0006] Current heave-compensated cranes are limited in size. Traditional large cranes are limited in sea and weather conditions. Current self-elevating cranes are limited by water depth. Current semi-submersible cranes are limited by cost (typically around $1 billion per vessel).

[0007] The present invention is directed to a crane stabilization system and assembly for offshore deepwater use that does not have the aforementioned limitations.

[0008] Specifically, the present invention is directed to utilizing a more versatile mast platform that is suitable for transport to and use in deepwater lifting operations.

[0009] Mast platforms offer high stability in all sea conditions. However, due to their large draft, they can only be fully deployed in deepwater. Therefore, when using a mast, it must be floated sideways to the deployment site before being erected vertically, and its considerable length makes transportation and deployment challenging.

[0010] The present invention is directed to an improved mast assembly that is telescopic to increase versatility and transportability via conventional vessels or offshore barges.

[0011] Furthermore, the present invention aims to provide a more universal stabilizing mechanism which is not limited by and is not substantially affected by sea conditions.

[0012] In particular, the present invention aims to provide an improved deep sea stabilisation assembly which allows pivotal movement between the support vessel and the mast during use, such that industrial equipment supported by the mast is substantially unaffected by changes in sea conditions.

[0013] The industrial equipment may be, for example but not limited to, a platform (to allow maintenance of eg offshore equipment), a crane or a wind turbine. Summary of the Invention

[0014] According to one aspect of the present invention, a stabilization assembly for deep water is provided, the assembly comprising a telescopic mast for fixing in a moonpool of a floating support vessel, the fixing mechanism comprising a universal joint fixed in the moonpool, the mast being suspended by the universal joint to allow the hull to move relative to the mast during use.

[0015] Preferably, the mast supports a crane.

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

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

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

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

[0020] Preferably, each segment comprises a spiral strake on the outer surface.

[0021] Preferably, the mast includes a collapsible bladder in the top section for adjusting the buoyancy of the mast.

[0022] Preferably, the bottom section includes ballast secured thereto.

[0023] Preferably, the mast includes an internal access ladder and platform which self-deploys during extension of the mast.

[0024] Preferably, the universal joint comprises an inner concentric ring and an outer concentric ring having pivot points at 90 degrees to each other.

[0025] Preferably, the inner ring is connected to the mast by two opposing pivot points at 180 degrees to each other and to the outer ring by two further opposing pivot points at 90 degrees to the mast connection.

[0026] Preferably, the outer ring is divided longitudinally into two halves, the two halves being pivotally connected at each end and sharing a common pinion with the inner ring.

[0027] Preferably, each half-ring has a counterweight fixed thereto at the end remote from the pivot connection.

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

[0029] Preferably, the counterweight is housed in recesses provided in the deck and hull of the vessel.

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

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

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

[0033] A structure is an industrial facility located in deep water offshore, such as a wind turbine or a platform. The platform may be a service platform for authorized personnel to maintain the wind turbine.

[0034] According to a fourth aspect of the present invention, there is provided a floating vessel for transporting the structure of the fourth aspect to a location in deep water offshore, the floating vessel comprising a universal joint as described in any of the preceding aspects fixed within the hull frame, the universal joint having means for receiving and suspending the telescopic mast when the telescopic mast is fully retracted during transport.

[0035] According to a fifth aspect of the present invention, there is provided a method for stabilizing a wind turbine in an offshore deepwater location, the wind turbine having a stabilization assembly as described in any of the preceding aspects, the method comprising the steps of: retracting the mast so that the ballast is flush with the bottom of the hull of the floating vessel; locking the universal joint and the counterweight in appropriate positions within the moonpool of the floating vessel; transporting the wind turbine to the offshore deepwater location; unlocking the universal joint and the counterweight to allow pivoting movement; and fully extending the mast downward to stabilize the wind turbine.

[0036] According to a sixth aspect of the present invention, there is provided a method for stabilizing a wind turbine in an offshore deepwater location, the wind turbine having a stabilizing assembly as described in any of the preceding aspects, and a method for stabilizing a wind turbine in an offshore deepwater location using a floating vessel as described in the fifth aspect, the wind turbine having a stabilizing assembly as described in any of the preceding aspects, the method comprising the following steps: when the mast is fully retracted, separating the universal joint to receive the wind turbine telescopic mast; clamping the universal joint around the mast; locking the universal joint and the counterweight in place to prevent any pivoting movement; transporting the wind turbine to an offshore deepwater location; unlocking the universal joint and the counterweight to allow pivoting movement; fully extending the mast downward to stabilize the wind turbine; and separating the universal joint to release the mast of the wind turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] At least one embodiment of the present invention will now be described with reference to the accompanying drawings, in which:

[0038] Figure 1 A crane stabilizing assembly constructed in accordance with a first embodiment of the present invention is shown;

[0039] Figure 2 Shown Figure 1 an assembly in which the mast is deployed;

[0040] Figure 3 shows the deployment of the mast;

[0041] Figure 4 is a planar cross-sectional view of the component;

[0042] Figure 5 is a schematic side sectional view of the assembly;

[0043] Figure 6 A crane stabilizing assembly constructed in accordance with a second embodiment of the present invention is shown;

[0044] Figure 7 Shown Figure 6 an assembly in which the mast is deployed;

[0045] Figure 8 A crane stabilizing assembly constructed in accordance with a third embodiment of the present invention is shown;

[0046] Figure 9 A crane stabilizing assembly constructed in accordance with a fourth embodiment of the present invention is shown;

[0047] Figure 10 A crane stabilizing assembly constructed in accordance with a fifth embodiment of the present invention is shown;

[0048] Figure 11 yes Figure 10a floor plan of the components; and

[0049] Figure 12 A wind turbine is shown deployed offshore. DETAILED DESCRIPTION

[0050] Figure 1 A crane stabilization assembly for offshore deepwater use is shown in general schematic form. The assembly comprises a floating industrial support vessel 2, such as an offshore barge.

[0051] The hull 2 ​​is constructed with a moonpool 4. A moonpool is a common feature of industrial deepwater vessels (such as offshore drilling platforms, diving support vessels, etc.) and is an opening in the bottom or base of the hull, typically used to provide access to the water surface, allowing technicians to lower tools or instruments into the sea.

[0052] The hull 2 ​​carries a mast 6. A mast is commonly used to provide a stable foundation for offshore equipment and is a large diameter vertical buoyant cylinder with a deep draft ballast that makes the structure less responsive to wind, waves and currents.

[0053] The mast 6 is suspended and fixed within the hull of the vessel and passes through the moon pool 4. Industrial equipment, such as a crane 8, is fixed to or near the top of the mast 6. As will be described below, the industrial equipment may be a platform or a wind turbine.

[0054] The mast 6 is telescopic to allow it to be deployed to a downwardly extended position to increase its draft, thereby providing a stable platform independent of the hull 2 ​​once the hull 2 ​​is in a deep water position.

[0055] Figure 2 The mast 6 is shown in an extended, deployed state.

[0056] Since the mast 6 is telescopic, the hull 2 ​​can sail in shallow waters carrying the telescopic mast 6 in a retracted state until the hull reaches deep waters, at which time the mast 6 can be deployed.

[0057] FIG3 illustrates the telescoping mechanism of mast 6. For ease of illustration, the crane is not shown. Mast 6 is constructed from three tubular sleeve segments 10, each with a gradually decreasing diameter to allow a third end segment 10C to slide within a second middle segment 10B, and the second segment to slide within a first top segment 10A. Any number of segments 10 can be used to vary the possible draft of mast 6.

[0058] The segments 10 may include helical strakes to increase hydrodynamic stability.

[0059] Alternatively, the mast may consist of at least one tube section and one truss section with heave plates.

[0060] Air can be pumped into a collapsible bladder located in the top section of the mast 6 to adjust the ballast / buoyancy to compensate for the crane load.

[0061] A permanent ballast 12 is fixed to the distal end of the third sleeve 10C to stabilize the tip of the mast 6 at the deepest point in the water.

[0062] The internal access ladder 14 and platform 16 may be pre-installed to deploy automatically when the mast 6 is extended, e.g. Figure 3B Most clearly shown.

[0063] Figure 4 is a plan cross-sectional view of a securing mechanism that suspends a mast 6 within the moonpool 4 of the hull 2. The mechanism secures the mast 6 in such a way that the hull 2 ​​can pivot about it when weather conditions change and the mechanism is deployed.

[0064] The suspension mechanism consists of a two-axis universal joint arrangement comprising an inner concentric ring 18 and an outer concentric ring 20 having pivot points at 90° to each other.

[0065] The inner ring 18 is connected to the mast 6 by two relative pivot points at 180° to each other and to the outer ring 20 by two further relative pivot points at 90° to the mast connection.

[0066] like Figure 5 As shown, the outer ring 20 is divided longitudinally into two halves 22 which are pivotally connected at each end and share a common pinion 24 with the inner ring 18 .

[0067] The end of each half-ring 22 remote from the pivot connection 26 has a counterweight 28 fixed thereto by an arm 30 supported by a vertically oriented shaft and bearing point 32 fixed to the inner wall of the moonpool 4 to form a fulcrum.

[0068] The counterweight 28 extends and is housed within a recess 34 provided in the deck and hull 2 ​​of the vessel 2 .

[0069] When the mast 6 is deployed in deep water offshore, the gimbal and counterweight compensate for the heave, pitch and roll experienced by the hull 2 ​​.

[0070] During transport, the universal rings 18, 20 and the counterweight 28 are locked in place. At this point, the universal joints and counterweight 28 are locked by locking pins and the mast 6 is telescoped back into the crane tower until the top of the ballast 12 is flush with the bottom of the hull 2.

[0071] If necessary, the crane can be further compensated by adding an extending counterweight opposite the jib, a heave compensating winch, or a spring heave compensator above the hook.

[0072] Once in position, the pins locking the universal joints are removed and the mast 6 deployed before the crane jib is raised. Once the mast 6 is fully extended, the hull 2 ​​can move independently of the mast 6. The counterweight 28 is typically chosen to be equal to the weight of the entire crane structure (excluding the crane load).

[0073] The surge, roll and yaw motions are controlled by driving the thrusters on the hull 2 ​​.

[0074] Figure 6 and Figure 7 Another embodiment of the invention is shown which provides a hull 36 having a large deck area and two moon pools 38. The deck area is divided into two platform sections 40, each having a motion compensation mechanism as described above.

[0075] Figure 6 The hull 36 is shown docked in a shallow harbor. As can be seen, in this example, the masts supporting each platform 40 are fully retracted. The universal joint 42 and the counterweight 44 are locked in place. The hull 36 can now be taken to sea.

[0076] Figure 7 The hull 36 is shown in a deepwater deployment position. In this case, the masts 46 of both platforms have been deployed to be independent of the movement of the hull 36 to stabilize the platform deck.

[0077] Figure 8 Another embodiment of the present invention is shown, which provides a hull 36, which includes a crane mast 6 as described above in one part of the deck area and a platform 40 in another part. In the figure, the crane mast 6 and the platform mast 46 are both deployed to stabilize the crane 8 and the platform 40 respectively.

[0078] Figure 9 Another embodiment of the invention is shown, which provides a hull 2 ​​with a single moonpool 4 , and a mast 6 of a crane simultaneously supporting a platform 40 .

[0079] Figure 10 and Figure 11 A hull 48 is shown that can carry a wind turbine 50 for transport to an offshore deepwater location. The wind turbine has a telescopic mast 6 as previously described, which is used to provide stability to the wind turbine 50 in the deepwater location. When the hull 48 is loaded in port, the mast 6 is in a retracted state.

[0080] In this case, the gimbal supporting the mast 6 is mounted within a frame 52 that is fixed to and extends from the side of the hull 48. Another gimbal and frame 52 are provided on the other side of the hull 2 ​​to allow for the simultaneous loading and transport of two wind turbines 50. Depending on the size of the hull 48, any number of wind turbines 50 can be loaded onto the hull 48 at the same time.

[0081] The mast 6 of each wind turbine is raised and lowered into the gimbal using a harbour crane 54 .

[0082] like Figure 11 As shown, each universal joint can be separated at one point to receive the retracted mast 6. Once in position, the universal joint is closed and secured with a universal clamp, and the universal mechanism and counterweight are locked in place for transport.

[0083] Once the deepwater location is reached, each universal joint is unlocked in turn and the mast 6 deployed. Weight transfer is also compensated for by using the ballast tanks on the hull 48. Once the mast 6 is fully deployed and each wind turbine 50 is supported and the anchors are secured, the universal clamps are released and the hull 48 can be moved away using the side thrusters.

[0084] Figure 12 The fully supported wind turbine 50 is shown with the mast 6 deployed.

Claims

1. A stabilization assembly for deep water, the assembly comprising a telescopic mast for fixing in a moon pool of a floating support vessel, the fixing mechanism comprising a universal joint fixed in the moon pool, the mast being suspended by the universal joint to allow the hull to move relative to the mast during use.

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

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

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

5. A stabilising assembly according to any preceding claim, wherein the mast is configured with at least two tubular sleeve sections, one of which is slidable within the other to telescopically extend or retract the mast.

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

7. A stabilising assembly according to claim 5 or 6, wherein each segment comprises a spiral strake on an outer surface.

8. A stabilising assembly according to any one of claims 5 to 7, wherein the mast comprises a collapsible bladder in a top section for adjusting the buoyancy of the mast.

9. A stabilising assembly according to any one of claims 5 to 8, wherein the bottom section includes ballast secured thereto.

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

11. A stabilising assembly according to any preceding claim, wherein the universal joint comprises inner and outer concentric rings having pivot points at 90 degrees to each other.

12. The stabilizing assembly of claim 11 wherein the inner ring is connected to the mast by two opposing pivot points 180 degrees from each other and to the outer ring by two further opposing pivot points 90 degrees from the mast connection.

13. The stabilizing assembly of claim 12, wherein the outer ring is longitudinally divided into two halves, the two halves being pivotally connected at each end and sharing a common pinion with the inner ring.

14. A stabilising assembly according to claim 13, wherein each half-ring has a counterweight secured thereto at an end remote from the pivot connection.

15. A stabilisation assembly according to claim 14, wherein each counterweight is secured to the outer ring by an arm supported by a vertically oriented shaft and bearing point secured to the inner wall of the moonpool to form a fulcrum.

16. A stabilising assembly according to claim 15, wherein the counterweight is housed within recesses provided in the deck and hull of the vessel.

17. A stabilising 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, each moonpool comprising a stabilising assembly according to any preceding claim.

19. A structure for use offshore in deep water, the structure having a telescoping mast secured thereto, the telescoping mast providing stability to the structure when extended.

20. A floating vessel for transporting a structure as claimed in claim 19 to a location in deep water offshore, the floating vessel comprising a universal joint as claimed in any preceding claim secured within the hull frame, the universal joint having means for receiving and suspending the telescopic mast when fully retracted during transport.

21. A method of stabilizing a wind turbine in an offshore deepwater location, the wind turbine having a stabilization assembly according to any one of claims 14 to 17, the method comprising the steps of: retracting the mast so that the ballast is flush with the bottom of the hull of the floating vessel; locking the universal joint and the counterweight in position within the moonpool of the floating vessel; transporting the wind turbine to an offshore deepwater location; unlocking the universal joint and the counterweight to allow pivotal movement; as well as The mast is fully extended downward to stabilize the wind turbine.

22. A method of stabilizing a wind turbine in an offshore deepwater location using a floating vessel according to claim 20, the wind turbine having a stabilization assembly according to any one of claims 14 to 17, the method comprising the steps of: When the mast is fully retracted, separating the universal joint to receive the mast of the wind turbine; clamping the universal joint around the mast; locking the universal joint and the counterweight in position to prevent any pivotal movement; transporting the wind turbine to an offshore deepwater location; unlocking the universal joint and the counterweight to allow pivotal movement; fully extending the mast downward to stabilize the wind turbine; as well as The universal joint is separated to release the mast of the wind turbine.

Images