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Title:
DEEP WATER HOISTING DEVICE, AND A METHOD TO LOWER A LOAD TO A DEEP SEA LEVEL
Document Type and Number:
WIPO Patent Application WO/2018/111097
Kind Code:
A1
Abstract:
A deep water hoisting device (1), comprising a reel (3), a flexible hoisting element (6) supported at least partly on the reel, and a hoisting unit, wherein, during use, the flexible hoisting element is suspended from the hoisting unit into the sea (30). The flexible hoisting element is a composite pipe comprising a polymer material and reinforcement fibers. A method is provided to lower a load to a deep sea level using such deep water hoisting device wherein the method comprises the steps of coupling a load to one end of the composite pipe, and lowering the one end of the composite pipe to the deep sea level.

Inventors:
VAN HATTEM ERIK (NL)
FRIJNS TOM LAURENT HUBERT (NL)
Application Number:
PCT/NL2017/050827
Publication Date:
June 21, 2018
Filing Date:
December 11, 2017
Export Citation:
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Assignee:
HEEREMA MARINE CONTRACTORS NL (NL)
International Classes:
B63B27/08; B66C23/52; F16L1/20
Domestic Patent References:
WO2004011837A12004-02-05
Foreign References:
GB2460671A2009-12-09
GB2466983A2010-07-21
EP2662524A12013-11-13
Other References:
None
Attorney, Agent or Firm:
VERMEULEN, M. (NL)
Download PDF:
Claims:
CLAIMS

1. A deep water hoisting device, comprising:

a reel,

a flexible hoisting element supported at least partly on the reel, and

a hoisting unit,

wherein, during use, the flexible hoisting element is suspended from the hoisting unit into the sea,

characterized in that the flexible hoisting element is a composite pipe comprising a polymer material and reinforcement fibers. 2. The deep water hoisting device of claim 2, wherein the hoisting unit comprises one or more tensioners, wherein the composite pipe is suspended from the one or more tensioners.

3. The deep water hoisting device of claim 1 or 2, wherein the hoisting unit is a pipe lay tower.

4. The deep water hoisting device of any of the claims 1-3, wherein the reinforcement fibers comprise glass and/or carbon fibers.

5. The deep water hoisting device of any of the claims 1-4, wherein the polymer material is selected from the group consisting of polyethylene (PE), polypropylene (PP), polyamide (PA), polyvinylidene fluoride (PVDF), polyether ether ketone (PEEK), Vinylester and/or epoxy.

6. The deep water hoisting device of any of the claims 1-5, wherein a length of the composite pipe is at least 1000 m, preferably at least 3000 m.

7. The deep water hoisting device of any of the claims 1-6, wherein the deep water hoisting device is arranged on a vessel, in particular a deep water construction vessel. 8. The deep water hoisting device of any of the claims 1-7, wherein the reel comprises an axis of rotation, and wherein the axis of rotation is arranged, during use, substantially horizontal.

9. The deep water hoisting device of any of the claims 1-8, wherein the reel is mounted on a deck of a vessel.

10. A method to lower a load to a deep sea level using a deep water hoisting device as claimed in any of the claims 1-9, comprising the steps of:

coupling a load to one end of the composite pipe, and

lowering the one end of the composite pipe to the deep sea level.

5

1 1 The method of claim 10, wherein the deep sea level is at least 1000 m below water surface, preferably at least 3000 m below water surface.

12. The method of claim 10 or 1 1 , wherein the load has a weight of at least 200 t 10 (200,000 kg), preferably at least 500 t (500,000 kg).

13. The method of any of the claims 10-12, wherein the method comprises the step of spooling of the composite pipe on the reel.

15 14. The method of any of the claims 10-13, wherein the hoisting unit is a pipe lay tower and the composite pipe is suspended from the pipe lay tower.

15. The method of claim 14, wherein the pipe lay tower comprises one or more tensioners, an aligner wheel and a straightener, wherein the composite pipe is guided over

20 the aligner wheel and through the straightener and suspended from the one or more

tensioners.

16. The method of any of the claims 10-15, wherein the composite pipe is substantially airtight such that it remains air filled below the water surface.

25

17. The method of any of the claims 10-15, wherein the composite pipe arranged below the water surface is filled with water.

18. The use of a pipe lay tower to lower a load to or lift a load from a deep sea level with 30 a flexible hoisting element supported at least partly on a reel, wherein the flexible hoisting element is a composite pipe comprising a polymer material and reinforcement fibers, and wherein the composite pipe is suspended from the pipe lay tower, in particular from one or more tensioners of the pipe lay tower, into the sea.

35

Description:
Title: Deep water hoisting device, and a method to lower a load to a deep sea level

The present invention relates to a deep water hoisting device. Such deep water hoisting device may be provided on a vessel, for example a deep water construction vessel. The invention further relates to a method to lower a load to a deep sea level using such deep water hoisting device. The deep water hoisting device may also be used in a method to lift an object from a deep sea level to close to the water surface.

A deep water hoisting device is configured to lower loads to a deep sea level, for example at least 1000 m, preferably at least 3000 m below the water surface.

A deep water hoisting device known in the art for instance comprises a storage winch, a traction winch, and a hoisting device, which is routed from the storage winch to the traction winch, and from the traction winch to an overboard location. Routing of the hoisting device over the vessel is typically done via one or a number of sheaves.

In a known embodiment of a deep water hoisting device steel wire ropes are used as hoisting element. A drawback of the use of steel wire ropes is that these steel wire ropes have a high specific weight, also under water. With an increasing water depth, an increasing part of the total hoisting capacity will be used to carry the weight of the steel wire hoisting element, for example resulting in a loss of hook load capacity of around 15% per 1000m water depth. As a consequence, a hoisting device having a working load limit of around 500 metric tonnes (in this application indicated with SI approved unit t; in practice also indicated as mT ) (500,000 kg ) at the water surface, will only have left a payload lifting capacity of around 170 1 (170,000 kg) at 4500m depth.

As an alternative to steel wire ropes as hoisting elements, there are also fibre rope wires. These are much lighter, and can be around neutral buoyant under water. These wires are not yet proven technology for high capacity, deep water hoisting wires and can have issues with generation of heat when bend around sheaves multiple times.

A fibre rope hoisting device as well as a steel wire rope hoisting device suitable for lowering a large load to ultra-deep water depths require very large storage and traction winches to store and deploy the wires. These are expensive and space consuming on a vessel.

It is an object of the invention to provide an improved deep water hoisting device, or at least to provide an alternative.

The invention provides a deep water hoisting device, comprising:

a reel,

a flexible hoisting element supported at least partly on the reel, and a hoisting unit,

wherein, during use, the flexible hoisting element is suspended from the hoisting unit into the sea,

characterized in that the flexible hoisting element is a composite pipe comprising a polymer material and reinforcement fibers.

An advantage of a composite pipe is that it is much lighter than conventional hoisting elements, such as steel wire ropes. As a result, the depth to which a load can be lowered is less limited by the weight of the steel ropes.

Depending on the materials used, as well as the amount of fibers within the composite pipe, the material of the composite pipe may have a specific weight of for example 1200 kg/m3 - 2500 kg/m3.

In an embodiment, the composite pipe is substantially airtight such that it will be air filled during use, and may have an approximately neutral weight under water, such that the full capacity of the hoisting unit remains available down to the seabed. The specific weight of the composite pipe, including the air in the composite pipe, under water is preferably in the range of 900 kg/m3 - 1 100 kg/m3, more preferably in the range of 950 kg/m3 - 1050 kg/m3.

The depth that can be reached with the system is then almost only limited by the length of the composite pipe, which is at least 1000 m, preferably at least 3000 m. The diameter of the composite pipe may for example be in the range of 100 mm to 600 mm, for example depending on the required lifting capacity. Any other suitable diameter may also be used.

In another embodiment, the composite pipe may be filled with water during lowering into the sea. This has the advantage that the composite pipe does not have to be designed for the very high compression forces at large water depths. On the other hand, this will mean that the specific weight of the composite pipe under water will be higher than in the case an air filled composite pipe will be used. Depending on the materials used, as well as the amount of fibers within the composite material, the composite pipe may for example have a specific weight of 1200 kg/m3 - 2500 kg/m3. Compared to a system with steel wire ropes, still a significant weight benefit can be achieved.

In an embodiment, the hoisting unit comprises one or more tensioners, wherein the composite pipe is suspended from the one or more tensioners. Tensioners are well known equipment for holding and lowering loads. The tensioners may be configured to hold the composite pipe and to lower, when desired, the composite pipe and a load coupled to the composite pipe into the sea. The tensioners may in combination have a load capacity of at least 500 t (500,000 kg). For example, the hoisting unit comprises two tensioners each having a load capacity of at least 300 t (300,000 kg), for instance about 400 t (400,000 kg). In an embodiment, the hoisting unit is a pipe lay tower. Some embodiments of known deep sea construction vessels are equipped with a pipe lay tower fitted for reel-lay of pipelines. Such pipe lay tower may comprise one or more tensioners that for example can deploy a 100 to 600 mm diameter pipeline from a reel and lower it to the seabed. According to this embodiment, the composite pipe may be spooled on the reel, and the reel may be rotatably arranged on a vessel. One end of the composite pipe may be led over the pipe lay tower.

An advantage of the system according to the invention is that, on board of a pipelay vessel, the pipelay equipment can also be utilized for deep water lowering activities, not requiring large additional storage or traction winches.

An object to be lowered into the sea may be attached to the end of the composite pipe and lowered into the sea to a deep sea level of at least 2500 m below the water surface, for example to the seabed. The one or more tensioners are used to hold and lower the composite pipe and the object coupled to the composite pipe.

In an embodiment, the hoisting unit, in particular the pipe lay tower, comprises an aligner wheel and/or a straightener, wherein the composite pipe, during use, is guided over the aligner wheel and/or through the straightener, respectively.

In an embodiment, the reinforcement fibers comprise glass and/or carbon fibers and/or the polymer material may be selected from the group consisting of polyethylene (PE), polypropylene (PP), polyamide (PA), polyvinylidene fluoride (PVDF), polyether ether ketone (PEEK), Vinylester and/or epoxy.

In an embodiment, the deep water hoisting device is arranged on a vessel, in particular a deep water construction vessel. The hoisting unit and the reel may for instance be arranged on a deck of the vessel. The reel may be held by a bracket configured to rotatably support such reel.

In an embodiment, the reel comprises an axis of rotation, and wherein the axis of rotation is arranged, during use, substantially horizontally. In such embodiment a bracket may be provided for the wheel to hold the wheel in an orientation wherein the reel may be rotated about an horizontal axis of rotation. It is remarked that the horizontal axis of the reel is defined with respect to a vessel being in a neutral position with respect to roll of the vessel.

The invention further provides a method to lower a load to a deep sea level using a deep water hoisting device as claimed in any of the claims 1-9, comprising the steps of: coupling a load to one end of the composite pipe, and

lowering the one end of the composite pipe to the deep sea level

The deep sea level is typically at least 1000 m below the water surface, preferably at least 3000 m below the water surface. The method may for instance be used to lower objects to the sea bottom wherein the sea bottom is at least 1000 m below the water surface.

The method of the invention is in particular useful to lower objects with a relatively large weight to the bottom of the sea. The load may for example have a weight of at least 200 t (200,000 kg), preferably at least 500 t (500,000 kg).

In an embodiment, the method may further comprise the step of spooling of the composite pipe on the reel and/or placing the reel loaded with composite pipe on a deck of a vessel.

In an embodiment, wherein the hoisting unit is a pipe lay tower and the composite pipe is suspended from the pipe lay tower.

In an embodiment, wherein the pipe lay tower comprises one or more tensioners, an aligner wheel and a straightener, wherein the composite pipe is guided over the aligner wheel and through the straightener and suspended from the one or more tensioners.

In an embodiment, the composite pipe is substantially airtight such that it remains air filled below the water surface.

In another embodiment, the composite pipe arranged below the water surface is filled with water.

The invention also provides the use of a pipe lay tower to lower a load to or lift a load from a deep sea level with a flexible hoisting element supported at least partly on a reel, wherein the flexible hoisting element is a composite pipe comprising a polymer material and reinforcement fibers, and wherein the composite pipe is suspended from the pipe lay tower, in particular from one or more tensioners of the pipe lay tower, into the sea.

The invention further provides a method to lift a load from a deep sea level using a deep water hoisting device as claimed in any of the claims 1 -9. Figure 1 shows an embodiment of a deep water hoisting device according to the invention.

Figure 1 shows a deep water hoisting device, generally indicated by reference numeral 1. The deep water hoisting device 1 is arranged on a deep water construction vessel 2, which is only partly shown. The deep water hoisting device 1 is configured to lower an object 20 to a deep sea level, at least 2500 m below the water surface 30, for example to place the object 20 on the bottom of the sea.

The deep water hoisting device 1 comprises a reel 3 which is arranged in a bracket 4 mounted on a deck 5 of the vessel 2. The bracket 4 is configured to rotatably hold the reel 3 in a position such that the reel 3 may be rotated about a substantially horizontal axis, when the vessel 2 is in a neutral roll position. A composite pipe 6 is spooled on the reel 3. The composite pipe 6 may have a length of at least 4000 m and a diameter of, for example, 100 mm - 600 mm. The reel 3 may have a cylindrical support surface to support the composite pipe 6 spooled on the reel 3, having a diameter of at least 10 m, for example about 16 m.

The composite pipe 6 is used as a flexible hoisting element to hold an object 20 that is to be lowered to a deep sea level.

The composite pipe 6 comprises a polymer material and reinforcement fibers. The polymer material may be any suitable material and may for example be polyethylene (PE), polypropylene (PP), polyamide (PA), polyvinylidene fluoride (PVDF), polyether ether ketone (PEEK), Vinylester and/or epoxy.

The reinforcement fibers of the composite pipe 6 may comprise glass and/or carbon fibers, or any other suitable fiber.

Depending on the materials used, as well as the amount of fibers within the composite pipe, the material of the composite pipe may have a specific weight of for example 1200 kg/m3 - 2500 kg/m3.

The advantage of the use of a composite pipe 6 as hoisting element for a deep water hoisting device is that the composite pipe 6 is much lighter than steel wires or other known hoisting elements, while at the same time the composite pipe 6 provides sufficient strength to lower heavy loads of at least 200 t (200,000 kg) to a deep sea level of more than 1000 m, preferably more than 3000 m. As a result of the low weight of the composite pipe 6, the depth to which an object 20 can be lowered into the sea is not limited or substantially less limited by the weight of the hoisting element.

The composite pipe 6 is led through a pipe lay tower 7 arranged on the deck of the vessel 2. The pipe lay tower 7 acts as hoisting unit to hold and lower the composite pipe into the sea. The pipe lay tower 7 comprises for instance two tensioners 8 configured to hold the composite pipe 3 and the object 20 attached to the composite pipe 3. The two tensioners 8 both are configured to hold the load as well as lowering the object, when desired. Each of the tensioners 8 is configured to hold for instance a weight of 400 t (400,000 kg) such that the pipe lay tower has a total load capacity of 800 t (800,000 kg). In an alternative

embodiment, a hoisting unit using friction clamps may be used.

The pipe-lay tower 7 further comprises an aligner wheel 12 and a straightener 9. The composite pipe 6 is guided over the aligner wheel 12 and through the straightener 9. The aligner wheel 12 may have for example a diameter of 18 m. The vessel 2 further may comprise a moon pool 10 through which the composite pipe 6 is guided to enter into the sea. In the moon pool 10, roller boxes 1 1 are provided to provide guidance of the composite pipe 6 into the sea. The use of the composite pipe 6 as hoisting element in the deep water hoisting device 1 may comprise the following steps.

A composite pipe 6 of sufficient length is spooled on the reel 3. This can be carried out while the reel 3 is supported on the bracket 4 and on the vessel 2, but will preferably be performed at another location, for example on another vessel or onshore. The reel 3 may be lifted with a crane into the bracket 4 in a suitable orientation with an axis of rotation substantially horizontal. Alternatively, the reel may be lifted on board with the crane together with the bracket.

Then the composite pipe 6 is led through the pipe laying tower 7, in particular over the aligner-straightener 9, through the tensioners 8 and through the roller boxes 1 1 , until one end of the composite pipe 6 extends through the moon pool 10 into the sea. This operation is similar to the introduction of a pipeline into the pipe laying tower, making optimal use of the same equipment and procedures.

The deep water hoisting device 1 is now ready to lower an object 20 to a deep sea level. The object 20 may be coupled to the end of the composite pipe 6, while for example the object 20 is suspended into the sea from a crane on the same or another vessel. After the weight of object 20 is completely transferred to the deep water hoisting device 1 , the object 20 may be lowered into the sea to a desired level below the water surface 30.

The composite pipe 6 is suspended from the tensioners 8 such that the weight of the object 20 is completely held by the tensioners 8, and wherein during lowering of the object 20 the tensioners will lower the composite pipe 6, while the composite pipe 6 is unreeled from the reel 3.

The composite pipe 6 is substantially airtight such that it will be air filled during use. The specific weight of the composite pipe, including the air in the composite pipe, under water may be in the range of 900 kg/m3 - 1 100 kg/m3.

Since the composite pipe 6 has a low under water weight, the load capacity of the tensioners 8 is hardly used to hold the load of the composite pipe 6 even when hundreds of meters of composite pipe 6 are suspended from the tensioners 8. As a result, the load capacity of the tensioners 8 remains practically fully available for holding the object 20. As a result, the object 20 can be lowered to a very large depth, only limited by the length of the composite pipe, which may be over 4000 m, without the need of extra load capacity for holding the length of composite pipe 6 suspended from the tensioners 8.

In an alternative embodiment of the composite pipe 6, the part of the composite pipe 6 below the water surface may be filled with water. This results in a higher specific weight of the composite pipe 6 below the water surface compared with an embodiment in which the composite pipe 6 is filled with air, but this embodiment has the advantage that the composite pipe 6 does not have to be designed for the very high compression forces at large water depths.

When desired, the deep water hoisting device 1 may also be used to lift objects 20 from a deep sea level to a location near the water surface 30. When the object 20 is lifted to this location, it may be coupled to another hoisting device 1 , such as a crane on the same or another vessel to lift the object 20 above the water surface, for example to arrange the object on the deck of a vessel. If the object 20 has suitable dimensions, the object 20 may also be moved through the moon pool 20 to the deck 5 of the vessel 2.

REFERENCE SIGNS

1 deep water hoisting device

2 vessel

3 reel

4 cradle

5 deck

6 composite pipe

7 pipe lay tower

8 tensioners

9 straightener

10 moon pool

1 1 roller boxes

12 aligner wheel

20 object

30 water surface