GB2533113A

GB2533113A - Floatable spool apparatus

Info

Publication number: GB2533113A
Application number: GB1421893.7A
Authority: GB
Inventors: Hatton Stephen
Original assignee: Magma Global Ltd
Current assignee: Magma Global Ltd
Priority date: 2014-12-09
Filing date: 2014-12-09
Publication date: 2016-06-15
Also published as: GB201421893D0

Abstract

A floatable spool apparatus 10 comprising a rotor assembly having a floatable base 14 and a spool mounted on the floatable base for spooling a spoolable medium 18 thereon. When in use, the floatable base is floatable and rotatable within or on a fluid. The floatable base may comprise an annular air filled tank or may be a solid structure. The apparatus may further comprise a fluid receptacle 20 adapted to receive the rotor assembly and hold the fluid on which the floatable base is floatable. A method of spooling a spoolable medium on a floatable spool is also disclosed.

Description

Floatable Spool Apparatus

SUMMARY OF THE INVENTION

The present invention relates to a floatable spool apparatus, system and method of spooling a spoolable medium.

BACKGROUND OF THE INVENTION

Spoolable flowlines and risers employed in the subsea industry may be typically stored on large diameter vertical spools or reels, which are used to deploy them offshore. Typically such spoolable media are made of steel and are therefore very heavy especially when spooled in long lengths. Existing spools used to store and install such spoolable media are designed to accommodate this high weight however they are generally large structures and require complex and expensive bearing systems.

Existing spools also employ complex bearing systems with fight fabrication tolerances making them more expensive and also subject to failure because of structural deflections which may result in uneven loading and bearing failures.

The subsea industry is increasingly considering lightweight composite pipes in place of steel based pipes. Despite their lower weight composite pipes present significant challenges. For example, composite pipes generally have a larger minimum bend radius than steel based pipes and hence even larger diameter spools are required.

Thus, despite the lower weight of the composite pipes the overall weight of the spool and the composite pipe still presents significant design problems relating to structural and bearing design issues. Moreover, there is a challenge in spooling a composite pipe onto or off a spool as it fleets up and down the spool drum efficiently and without overstressing or damaging the pipe.

SUMMARY OF THE INVENTION

A first aspect of the present invention is directed to a floatable spool apparatus comprising a rotor assembly comprising a floatable base and a spool mounted on the floatable base for spooling a spoolable medium thereon, wherein, in use, the floatable base is floatable and rotatable within or on a fluid.

In use, the floatable spool apparatus may be transferred to a desired location and positioned so that the rotor assembly, for example the floatable base of the rotor assembly lies within or on a fluid. The floatable base may be floatable at or on a fluid surface The rotor assembly, for example the floatable base of the rotor assembly may include sufficient buoyancy to float within or on a fluid while supporting the weight of the floatable base, the spool and any spoolable medium loaded onto the spool.

The rotor assembly may freely rotate within or on a fluid. The spool may rotate together with the floatable base to deploy or reel in the spoolable medium.

The floatable spool apparatus may allow support and rotation of heavy spools while minimizing the requirement for complex bearings.

The floatable base may comprise a wall structure that is sealed to prevent fluid ingress into the interior of the floatable base.

The wall structure of the floatable base may be made of or comprise any suitable material provided that the floatable base as a whole may float once positioned within or on a fluid supporting its own weight, the weight of the spool and the spoolable medium.

The wall structure of the floatable base may be made of metal or metal alloys such as steel or steel alloys. However, it should be understood that other materials such as metallic or composite materials may be used.

The wall structure of the floatable base may be made of aluminium.

The wall structure of the floatable base may be made of a high strength plastic composite material.

The floatable base may comprise one or more hollow structures.

The floatable base may include, for example be at least partially filled with a suitable light material.

The floatable base may include a material that has a lower density than the density of the fluid in order to provide the floatable base with sufficient buoyancy to float while supporting the weight of the spool and the spoolable medium.

The floatable base may be at least partially filled with a gas.

The floatable base may be at least partially filled with a fluid.

The floatable base may be at least partially filled with air.

The floatable base may comprise a gas tank.

The floatable base may comprise an air tank.

The buoyancy of the rotor assembly, for example of the floatable base of the rotor assembly, may be variable. The ability to adjust the buoyancy of the rotor assembly may permit the rotor assembly to accommodate different weights of spoolable medium, and/or permit the rotor assembly to sit at different heights within or on a fluid. This arrangement may provide benefits in permitting appropriate fleeting of the spoolable medium while being paid out and in.

The floatable base may permit a varying level of fluid, for example a liquid and/or a gas, to be accommodated therein. Such an arrangement may permit the effective buoyancy of the floatable base, and thus of the rotor assembly, to be adjusted.

The floatable base may be a solid structure made of a material that has lower density than the density of the fluid in order to provide the floatable base with sufficient buoyancy to float while supporting the weight of the spool and the spoolable medium.

The floatable base may comprise a foam material.

The floatable base may be of any suitable shape and construction provided that it can float and rotate when placed within or on a fluid.

The buoyancy of the floatable base may be modified, amongst other things, by the shape, dimensions and material of construction of the floatable base. For example, generally a larger floatable base may be needed for a heavier spoolable medium than for a lighter one.

The shape and dimensions of the floatable base may be selected to accommodate a minimum bend radius requirement of the spoolable medium.

The floatable base may have a generally cylindrical shape defining a side surface.

The floatable base may have a cylindrical shape defining a side cylindrical surface The floatable base may have a generally convex or concave side surface.

The floatable base may have any suitable bottom and top surfaces. Generally, the shape of the top surface of the floatable base may be selected to accommodate the spool and/or spoolable medium.

The floatable base may have a bottom surface of any suitable shape.

The floatable base may have a flat bottom surface so that it may rest in a stable manner on top of a flat surface of a base or container when not positioned within or on a fluid, for example during transportation.

The floatable base may comprise a convex, concave or conical bottom surface that may cooperate with a corresponding concave, convex or conical surface of a base or container when not positioned within or on a fluid, for example during transportation.

The floatable base may have an annular or ring shape. An annular shape may allow accommodating spoolable media having a large minimum bend radius requirement.

The floatable base may comprise an annular tank.

The floatable base may be a modular structure comprising two or more parts. Selection of the buoyancy characteristics of each part may allow modifying the overall buoyancy of the apparatus to fit a particular application.

The floatable base may be made of two or more interconnecting modular parts.

The spool may be of any suitable shape. For example, the spool may be a cylinder defining a substantially cylindrical side surface (also referred to hereinafter as the drum surface) for winding the spoolable medium thereon.

The spool may be a cylinder having a continuous side surface for spooling the spoolable medium thereon.

The spool may be a cylinder having a discontinuous side surface for spooling the spoolable medium thereon.

The spool may comprise a plurality of beam elements arranged in a cylindrical configuration to form a support arrangement for the spoolable medium.

The spool may comprise a top ring. The beam elements may extend between the top ring and the floatable base.

The beam elements may contribute to the buoyancy of the apparatus. For example, the beam elements may be hollow pipe elements such as hollow rods or elongated hollow rectangular beams.

The spool and the floatable base may be manufactured as an integral part.

The spool and the floatable base may be manufactured as separate modular pieces that can be assembled together.

The spool and the floatable base may be made of same or similar materials.

The spool and the floatable base may be made of different materials.

The floatable spool apparatus may comprise a rotational drive unit for controlling the rotation of the rotor assembly.

The rotational drive unit may comprise a motor.

The rotational drive unit may be operatively connected to the spool.

The rotational drive unit may be operatively connected to the floatable base.

The rotational drive unit may comprise any suitable drive unit.

According to one embodiment, the rotational drive unit may comprise a central drive having a throughbore, with a spindle positioned through the throughbore. The spindle may be operatively connected to the spool via a connector so that upon operation of the central drive the spindle rotates and imparts rotational movement to the rotor assembly via the connector.

The apparatus may be used with any spoolable medium. For example the apparatus may be used with wireline, slickline, coiled tubing, compliant guide pipes, steel pipes, flexible pipes and the like.

The spoolable medium may be made of any suitable material. For example the spoolable medium may be made of steel or steel alloys such as steel pipes used as risers and flowlines in subsea applications The spoolable medium may be made of a composite material. Such a composite material may comprise a matrix material and a plurality of reinforced fibres embedded within the matrix material.

The apparatus may be used for spooling flexible pipes.

The apparatus may be used for spooling flexible risers, flowlines, jumpers and the like in subsea applications.

Flexible pipes, also referred to as flexible composite pipes, may generally exhibit a larger minimum bend radius than steel pipes and hence may require larger diameter spools which may be problematic with existing design spool apparatuses. The present invention apparatus may accommodate more readily larger diameter spools.

The fluid may be any suitable fluid provided that it has a certain density to allow floating of the floatable base.

The fluid may be water such as sea water.

The fluid may be a body of water.

The fluid may be contained within a fluid receptacle.

The fluid receptacle may form part of the floatable spool apparatus.

The fluid receptacle may comprise a recess defined within a support structure.

The fluid receptacle may comprise a container defined within a support structure.

The support structure may form part of the floatable spool apparatus.

The support structure may be a separate part from the apparatus.

The support structure may be a floating structure such as a floating platform or vessel.

In some embodiments the floating structure may comprise a barge.

The support structure may be a non-floating structure.

The fluid receptacle may be part of a dedicated floating structure such as a barge specially designed to also accommodate the other parts of the floatable spool apparatus.

The fluid receptacle may comprise at least one port for adding fluid in the fluid receptacle The fluid receptacle may comprise at least one port for removing fluid from the fluid receptacle.

The fluid receptacle may comprise at least two ports, a first port for adding fluid in the fluid receptacle and a second port for removing fluid from the fluid receptacle.

The fluid receptacle may have any suitable shape and size provided that it can accommodate the floatable base and allow it to freely rotate therein once it is floated.

The fluid receptacle may have a bottom surface adapted to accommodate the bottom surface of the floatable base. So for example the fluid base may have a generally flat bottom surface adapted to allow a floatable base having a flat bottom surface to rest in a stable manner thereon when the fluid receptacle is empty.

However, different shape bottom surfaces for the fluid receptacle may be used. For example the fluid receptacle may have a curved shape or profile, in which case the floatable base may have a corresponding curved profile.

The fluid receptacle may have a substantially cylindrical shape.

The fluid receptacle may have an annular or ring shape adapted to accommodate an annular floatable base. Having an annular shape may facilitate the apparatus to accommodate spoolable media having a large minimum bend radius requirement. The annular shape also may allow better utilization of the available space especially in floating structures where space is at a premium.

According to one embodiment of the present invention, the fluid receptacle may have an annular or ring shape defined by an annular recess formed within a support structure. A central part of the support structure surrounded by the annular recess may be substantially free space that could be used as needed.

The floatable base may have a generally cylindrical shape defining a side surface that cooperates with the side surface of the fluid receptacle to allow free rotation of the floatable base within a fluid medium within the fluid receptacle.

The fluid in the fluid receptacle may be any suitable fluid provided that it has a certain density to allow floating of the floatable base.

The fluid in the fluid receptacle may be water such as sea water.

The level of the fluid in the receptacle may be adjustable. This may be advantageous, for example, for adjusting the fleet angle of the spoolable medium as it is reeled in or out and optimizing the spooling operation.

The level of the fluid within the receptacle may be adjustable via a pump system.

The present invention apparatus may allow performing the spooling operation within an optimum fleet angle range by adjusting the fluid level in the fluid receptacle.

The apparatus may comprise a control system for controlling the fluid level inside the fluid receptacle in order to be able to modify the level of the fluid as may be needed in order to more efficiently and evenly reel in or deploy the spoolable medium. Any suitable control system may be used.

According to one embodiment the control system may include a level measurement device for measuring the fluid level within the fluid receptacle. The apparatus may include a device for measuring the position of the spoolable medium in relation to the spool as it spooled off or onto the spool. The apparatus may include a processor for determining the desired level within the fluid receptacle. A control valve may be provided for controlling fluid flow into or out of the fluid receptacle as may be needed.

A guide arrangement may be provided to assist guidance of the rotor assembly during rotation within the fluid receptacle. The guide arrangement may assist to maintain the rotor assembly in a concentric configuration with the fluid receptacle.

In some embodiments the guide arrangement may comprise one or more roller wheels.

Such roller wheels may be provided on one or both the rotor assembly (for example on the floatable base) and the fluid receptacle.

Another aspect of the present invention is directed to the use of the floatable spool apparatus as described for spooling a spoolable medium.

Yet another aspect of the present invention is directed to a method for spooling a spoolable medium, the method comprising: providing a floatable spool apparatus comprising a rotor assembly which includes a floatable base and a spool mounted on the floatable base, wherein the spool carries a spoolable medium thereon; positioning the floatable spool apparatus on or within a fluid; and rotating the apparatus to spool a spoolable medium onto or off the spool.

Yet another aspect of the present invention is directed to a fluid receptacle adapted to receive a rotor assembly of a floatable spool apparatus. The fluid receptacle may have any of the features as described.

Yet another aspect of the present invention is directed to a floatable spool system comprising: a fluid receptacle formed within a support structure; a rotor assembly mounted within said fluid receptacle, wherein the rotor assembly comprises a floatable base and a spool mounted on said floatable base for spooling a spoolable medium thereon; wherein upon addition of a fluid inside the fluid receptacle the floatable base floats and becomes rotatable within the fluid receptacle.

It should be understood that features described in relation to one aspect may be applied to any other aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further described, by way of non-limiting examples only, and with reference to the accompanying drawings, in which: Figure 1 shows a schematic side cross-sectional view of a floatable spool apparatus, according to an embodiment of the invention; Figure 2 is a top view of the embodiment of Figure 1; Figure 3 shows a side cross-sectional view of a rotor assembly of the apparatus of Figure 1, removed from a support barge; and Figures 4 and 5 illustrate the apparatus of Figure 1 at varying floating levels during spooling.

DETAILED DESCRIPTION

Referring now to Figures 1 to 3, one embodiment of a floatable spool apparatus, generally identified by reference numeral 10, in accordance with the present invention is provided. The apparatus 10 is shown mounted on a floating structure such as a barge 40 which includes an annular fluid receptacle 20. The fluid receptacle is shown in Figure 1 entirely empty. It should be understood, however, that the invention is not limited to offshore applications. Thus the floatable spool apparatus 10 may be mounted on any suitable support structure comprising a suitable fluid receptacle 20 for accommodating the apparatus 10 and may be used in land operations.

The apparatus 10 comprises a rotor assembly or carousel structure, generally identified by numeral 12. The carousel structure 12 comprises a top ring 28 having a substantially horizontal configuration in relation to the barge 40. The carousel structure 12 further comprises a plurality of vertical rods 16 arranged in a generally cylindrical configuration. Each rod 16 is attached at a first upper end 16a to the top ring 28 and at a second lower end 16b to an annular floatable base 14. The vertical rods 16 form a discontinuous cylindrical surface for storing a spoolable medium 18 thereon.

The rods 16 are arranged around a desired circumference selected to accommodate a particular spoolable medium 18, for example to accommodate a minimum required bend radius of the spoolable medium 18.

The apparatus 10 may accommodate any spoolable medium. However, in the present exemplary embodiment the spoolable medium 18 comprises a composite pipe structure. The pipe structure may comprise a wall formed at least partially from a composite material of a matrix material (e.g., PEEK) and a plurality of reinforcing fibres (e.g., carbon fibre) within the matrix material.

The floatable base 14 as shown is an annular continuous tank having top 14a, bottom 14b, and side walls 14c, 14d. The walls of the tank 14 may be made of any suitable material, such as for example metal or metal alloys such as steel or steel alloys. Other light but sturdy composite materials may also be used.

The tank 14 is sealed to prevent the ingress of any fluid from the fluid receptacle 20 into the interior of the tank. The interior of the tank may typically contain air, however, it is envisioned that the interior of the tank may contain other materials depending upon the specific requirements for buoyancy, structural support and/or stability required for a particular application.

The tank 14 provides structural strength. The tank also provides, when immersed in a fluid such as water inside the fluid receptacle 20, sufficient buoyancy to float the carousel structure 12. The dimensions and construction of the annular tank 14 are designed so that the upthrust or buoyancy force can support the carousel 12 self-weight and also that of the spoolable medium 18.

Some or all of the vertical rods 16 may be hollow and may also be sealed to prevent fluid from entering the rods when a portion of the rods is immersed in the fluid. Thus the rods may contribute to the overall buoyancy of the tank 14 and the carousel 12.

The rods 16 may be attached to the top wall 14a of the tank by any suitable means such as by welding, bolting or the like.

Once the spoolable medium 18 has been wound onto the carousel 12 the carousel 12 together with the spoolable medium 18 may be lifted and lowered into the annular fluid receptacle 20 fabricated on barge 40.

In an alternative embodiment, the annular fluid receptacle 20 may be formed within a support structure that may be in turn positioned on a barge or any other structure floating or not floating.

The depth of the fluid receptacle 20 may be selected such that a large proportion of the height of the carousel 12 is contained within the hull of the barge 40, at least when the fluid receptacle 20 is empty, as shown in Figure 1. This may provide protection and stability of the carousel 12 during transportation, for example.

As illustrated in Figure 1, the apparatus 10 may further comprise a rotational drive unit comprising a central drive 24, a spindle 26, a connector 32 (Figure 2) and a motor (not shown). The central drive 24 is positioned at a central position relative to the carousel structure 12 and is attached to a central portion 40c of the support structure 40.

The central drive 24 has a throughbore 24b to operatively receive the spindle 26. The spindle 26 is positioned through the throughbore 24b of the central drive 24 and extends above and below the throughbore 24b. Upon operation of the central drive 24 the spindle 26 rotates and imparts the rotational movement to the carousel 12 via the connector 32.

Rotation of the carousel 12 within the fluid receptacle 20 may be controlled using central drive unit 24 driven by a hydraulic motor (not shown).

Spindle 26 extends below the central drive 24 and is designed to telescope up and down with the rise and fall of the carousel 12 within a corresponding spindle recess 30 defined in a central portion 40c of the support structure 40, while the spindle 26 remains in operative connection with the central drive unit 24.

In operation, the barge 40 may sail to a desired offshore site and may be positioned to deploy the spoolable medium 18 spooled around the carousel 12. During transit the receptacle 20 may be empty so that the carousel 12 may be lowered to sit on top of the lower surface of the receptacle 20.

A fluid, such as sea water may be pumped into the annular fluid receptacle 20 until a desired depth is reached to allow for the carousel 12 to float, as illustrated in Figure 4. Once the carousel 12 floats in this manner, the spooling operation may commence by rotating the carousel 12 within the fluid receptacle 20. Such an arrangement may facilitate spooling without necessarily requiring complex bearings. Also the required force for rotating the carousel 12 may generally be lower than that required if a conventional spool is employed.

To assist guidance of the carousel, rubber roller wheels (not shown) may be provided around the side surface of the annular tank 14 to cooperate with the side surface of the annular receptacle 20 in order to maintain the carousel 12 in a concentric configuration within the receptacle 20.

During installation of the pipe the barge 40 may be moored against a dynamically positioned construction vessel to provide station keeping and to resist pipe back tension and torsional loads.

As the pipe 18 is spooled from/to the carousel 12 the position of the pipe departure advantageously should move or fleet up and down relative to the carousel 12. To accommodate this, the height of the carousel 12 may be adjusted relative to the barge deck by varying the water depth in the annular receptacle 20 so that the carousel 12 may float at a varying elevation.

The fluid receptacle 20 may comprise one or more ports (not shown) for use in varying the fluid volume in the fluid receptacle.

Figure 4 shows the carousel 12 at a minimum elevation with spooling occurring at a higher part of the side surface of the spool indicated by arrow H. Figure 5 shows the carousel 12 at a maximum elevation with spooling occurring at a lower part of the side surface of the spool indicated by arrow L. This way the present invention may adjust the fleet angle of the spoolable medium as it is spooled onto or off the drum of the spool by adjusting the fluid level in the fluid receptacle and in effect may act as a fleet angle compensator. This allows performing the spooling operation within an optimum fleet angle range.

Furthermore, the ability to vary the height of the carousel may permit adjustments to be made as the weight of the carousel varies during spooling.

Thus by lowering or raising the fluid level in the fluid receptacle the apparatus improves spooling of the spoolable medium in a more efficient and uniform and stable manner onto or off the carousel 12.

The carousel 12 may be loaded with multiple sections of spoolable medium 18 that may be deployed separately (or simultaneously), for example 4 to 6 lengths each of 3000m may be loaded on the carousel and installed as separate risers. In such an instance, each section of riser may be installed in a partition of the carousel to minimise fleeting distances for each riser section.

The fluid receptacle 20 of the embodiment shown in Figures 1-3 is an open recess without a top wall, however, in a different embodiment not shown the fluid receptacle may be a container having a top wall to prevent spilling of the fluid during transportation.

It should be understood that the embodiments described herein are merely exemplary and that various modifications may be made thereto without departing from the scope of the invention as claimed. For example, in some embodiments the buoyancy of the carousel 12 may be variable, for example by varying ballast levels or the like. Such an arrangement may facilitate a variation in the elevation of the carousel within the fluid receptacle. Such an arrangement may also permit adjustments to be made in accordance with a varying weight of the carousel, for example by virtue of the spoolable medium being spooled out or in.

Also it should be understood that features described with any one particular aspect of the invention or embodiment of the invention may be used with any other aspect or embodiment.

Claims

CLAIMS: 1 A floatable spool apparatus comprising a rotor assembly comprising a floatable base and a spool mounted on the floatable base for spooling a spoolable medium thereon, wherein, in use, the floatable base is floatable and rotatable within or on a fluid.
2. The apparatus according to claim 1, wherein the floatable base comprises a sealed wall structure.
3. The apparatus according to any preceding claim, wherein the floatable base comprises an air tank.
4. The apparatus according to any preceding claim, wherein the floatable base comprises an annular tank.
5. The apparatus according to any preceding claim, wherein the floatable base comprises a solid structure.
6. The apparatus according to any preceding claim, wherein the spool is cylindrical.
7. The apparatus according to any preceding claim, wherein the spool comprises a discontinuous support structure for supporting the spoolable medium thereon.
8 The apparatus according to any preceding claim, wherein the spool comprises a plurality of beam elements arranged in a cylindrical configuration to form a support structure of the spool.
9 The apparatus according to claim 8, wherein the spool comprises a top ring, each beam element being attached at an upper end to the top ring and at a lower end to the floatable base.
10. The apparatus according to claim 8 or 9, wherein the beam elements are hollow rods.
11. The apparatus according to any preceding claim, comprising a rotational drive unit for rotating the rotor assembly.
12. The apparatus according to any preceding claim, comprising a fluid receptacle adapted to receive the rotor assembly.
13. The apparatus according to claim 12, wherein the fluid receptacle has a curved shape or profile.
14. The apparatus according to claim 12, wherein the fluid receptacle has a substantially cylindrical shape.
15. The apparatus according to claim 12, wherein the fluid receptacle has an annular or ring shape.
16. The apparatus according to any of the claims 12 to 15, wherein the fluid receptacle comprises a fluid, the level of the fluid in the fluid receptacle being adjustable.
17. A method for spooling a spoolable medium, the method comprising: providing a floatable spool apparatus comprising a rotor assembly which includes a floatable base and a spool mounted on the floatable base, wherein the spool carries a spoolable medium thereon; positioning the floatable spool apparatus on or within a fluid; and rotating the rotor assembly to spool a spoolable medium onto or off the spool.
18. A fluid receptacle adapted to receive the floatable base of the floatable spool apparatus as in any of the preceding claims.
19. The fluid receptacle as in claim 21, the fluid receptacle comprising a recess formed on the deck of a floating structure.
20. A floatable spool system comprising: a fluid receptacle formed within a support structure; a rotor assembly mounted within said fluid receptacle wherein the rotor assembly comprises a floatable base and a spool mounted on said floatable base for spooling a spoolable medium thereon; wherein upon addition of a fluid inside the fluid receptacle the floatable base floats and becomes rotatable within the fluid receptacle.