GB2539450A

GB2539450A - Offshore pipe deployment method and apparatus

Info

Publication number: GB2539450A
Application number: GB1510562.0A
Authority: GB
Inventors: Alexander Tavner Charles; Peter William Jones Martin
Original assignee: Magma Global Ltd
Current assignee: Magma Global Ltd
Priority date: 2015-06-16
Filing date: 2015-06-16
Publication date: 2016-12-21
Also published as: GB201510562D0

Abstract

A method of manipulating a subsea pipe comprises coupling an autonomous marine drive unit 80, 82, 84 to a pipe 86, which in some aspects of the invention is a composite pipe having a wall comprising a matrix material and a plurality of reinforcing fibres embedded within the matrix material. The autonomous marine drive unit 80, 82, 84 is then operated to manipulate the pipe 86 within a marine environment. The autonomous marine drive unit 80, 82, 84 can be an autonomous surface vessel (ASV) or an autonomous underwater vessel (AUV), operated under the control of an autonomous control system. The unit 80, 82, 84, can have a thrust arrangement with a drive source, and a direction control arrangement. It can also comprise an azimuth drive unit. The unit 80, 82, 84 can be directly mounted to the pipe 86, and more than one unit can be coupled to the pipe. The units 80, 82, 84 can manipulate the pipe 86 on the surface of the water, or below the surface of the water, with the buoyancy of the pipe 86 controlled via sealing, flooding chambers within the pipe 86, or through the use of a pig.

Description

Intellectual Property Office Application No. GII1510562.0 RTM Date:27November 2015 The following terms are registered trade marks and should be read as such wherever they occur in this document: m-pipe (page 9, 13) Intellectual Property Office is an operating name of the Patent Office www.gov.uk /ipo

OFFSHORE PIPE DEPLOYMENT METHOD AND APPARATUS

FIELD

The present invention relates to methods and apparatus for deploying pipes offshore.

BACKGROUND

Many offshore industries require the use of pipe structures, such as to provide conduits for flow and/or equipment. For example, the offshore oil and gas industry utilises pipe structures in the form of marine risers, flowlines, jumpers, intervention lines, production lines, injection lines, control lines and the like, with typical pipe structures varying from a few meters in length to several thousands of meters.

Significant consideration is given to the design of a pipe structure to ensure it can meet its particular service conditions, such as pressures, mechanical loading, fatigue cycles, fluid compositions and the like. However, considerations must also be given to the procedures to deploy the pipe structures. In this respect, many offshore pipe structures are formed from metal, such as steel, and in some instances, such as in extremely long pipe sections, the pipes can be extremely heavy, requiring very specialised vessels and crew for both transportation and subsequent deployment/handling from the vessels. This can significantly affect the deployment and installation costs.

Furthermore, during deployment the pipe structures may be exposed to particular conditions, such as mechanical loading, which might not necessarily be present when in service. Nevertheless, designers must ensure that the pipe structures can survive the deployment process, which may lead to a pipe design which is over-engineered for its service conditions, but without such over-engineering would otherwise be at risk of being compromised during deployment.

SUMMARY

An aspect or embodiment relates to a method, comprising: coupling an autonomous marine drive unit to a composite pipe having a wall comprising a matrix material and a plurality of reinforcing fibres embedded within the matrix material; and operating the autonomous marine drive unit to manipulate the composite pipe within a marine environment.

The method may comprise autonomously operating the autonomous marine drive unit. Such autonomous operation may be achieved without human intervention. The autonomous marine drive unit may thus be un-manned.

The autonomous marine drive unit may comprise an autonomous control system for providing autonomous control of the marine drive unit. The method may comprise operating the autonomous marine drive unit under the control of the autonomous control system. During use, the autonomous control system may permit the marine drive unit to be controlled and operated without human intervention.

The autonomous control system may comprise one or more control algorithms, for example stored on memory, providing the necessary control instructions to provide autonomous control of the autonomous marine drive unit. The method may comprise loading one or more control algorithms on the autonomous control system.

The autonomous control system may comprise a controller for executing control instructions.

The autonomous marine drive unit may comprise a position determining arrangement or system, such as a GPS, radar, sonar, accelerometer, gyroscope or the like. The position determining arrangement or system may communicate with the controller.

The autonomous marine drive unit may comprise an antenna, such as a GPS antenna. 25 The autonomous marine drive unit may comprise a thrust arrangement for generating thrust. The thrust arrangement may be controlled by an autonomous control system. The thrust arrangement may comprise one or more thrusters. The thrust arrangement may comprise one or more propellers. The thrust arrangement may comprise one or more jet thrusters.

The autonomous marine drive unit may comprise a drive source. The drive source may be operationally connected to a thrust arrangement. The drive source may comprise a motor, such as an electric motor, hydraulic motor or the like. The drive source may comprise a pump, compressor or the like. The drive source may comprise an engine.

The autonomous marine drive unit may comprise a direction control arrangement. The direction control arrangement may comprise a rudder system. The direction control arrangement may comprise one or more azimuth thrusters. In such an arrangement the method may comprise coupling an autonomous marine azimuth drive unit to the composite pipe.

The autonomous marine drive unit may be provided on a marine vessel, wherein the method comprises coupling the composite pipe to the marine vessel. The marine vessel may thus be defined as an autonomous marine vessel. In such an arrangement the autonomous marine drive unit may manipulate the composite pipe via the marine vessel.

The method may comprise rigidly securing the composite pipe to the marine vessel. For example, the composite pipe may directly engage a structure, such as a deck structure of the marine vessel.

The method may comprise tethering the composite pipe to the marine vessel, for example via one or more towing members, such as ropes, cables, chains or the like. Such an arrangement may permit relative movement between the marine vessel and the composite pipe.

The marine vessel may comprise a floating vessel. In such an arrangement the marine vessel may be operable on a water surface. The marine vessel may comprise an autonomous ship, barge or the like. The marine vessel may comprise an Autonomous Surface Vessel (ASV) or an Unmanned Surface Vessel (USV).

The marine vessel may comprise a submersible vessel. In such an arrangement the marine vessel may be operable below a water surface. The marine vessel may comprise an Autonomous Underwater Vehicle (AUV).

The method may comprise directly mounting the autonomous marine drive unit to the composite pipe. In such an arrangement the composite pipe may define a marine vessel or vessel structure. This arrangement may minimise complexities, costs etc. associated with using separate marine vessels. Any suitable coupling arrangement may be used to couple the marine drive unit to the composite pipe. In some embodiments the method may comprise clamping the autonomous marine drive unit to the composite pipe.

The method may comprise coupling a single autonomous marine drive unit to the composite pipe. The method may comprise coupling multiple autonomous marine drive units to the composite pipe. In one embodiment the method may comprise coupling at least two autonomous marine drive units to the composite pipe, for example at least one drive unit at each end of the pipe.

The method may comprise providing communication between at least two, for example all autonomous drive units coupled to the composite pipe. Such communication may facilitate collective autonomous control of at least two, for example all autonomous drive units.

The method may comprise manipulating the composite pipe on the surface of a body of water. For example, the method may comprise operating the autonomous marine drive unit to drive the composite pipe along the surface of the body of water, for example towards a target location. The method may comprise operating the autonomous marine drive unit to maintain the composite pipe at a location, for example a target location on the surface of the body of water.

Manipulating the composite pipe on the surface of a body of water may expose the composite pipe to cyclical loading, for example due to wave motion, vortex shedding and the like. Such cyclical loading may be accommodated by the nature of the composite material of the pipe, for example by virtue of its higher strain capabilities and resistance to fatigue compared to an equivalent metallic pipe.

The method may comprise arranging the composite pipe to float on the surface of a body of water, to permit manipulation of the composite pipe on the surface of the body of water. The composite pipe may be floated by virtue of its inherent or natural buoyancy.

The method may comprise manipulating the composite pipe below the surface of a body of water. For example, the method may comprise operating the autonomous marine drive unit to drive the composite pipe through the body of water, for example towards a target location. The method may comprise operating the autonomous marine drive unit to maintain the composite pipe at a submerged location, for example a target submerged location. This arrangement may minimise loading on the composite pipe, for example cyclical loading from wave motion, although as noted above the nature of the composite material, in particular its higher strain capability and fatigue resistance may permit such cyclical loading to be readily accommodated.

The method may comprise submerging the composite pipe within a body of water, to permit manipulation of the composite pipe below the surface of the body of water.

The method may comprise controlling the buoyancy of the composite pipe. The method may comprise controlling the buoyancy of the composite pipe to permit said composite pipe to float on a body of water. The method may comprise controlling the buoyancy of the composite pipe to permit said composite pipe to sink into a body of water. The method may comprise controlling the buoyancy of the composite pipe to permit said composite pipe to be submerged to a desired depth.

The method may comprise controlling the buoyancy of the composite pipe by sealing one or more regions along the length of the composite pipe, such that said one or more sealed regions may be gas filled, for example air filled. In some embodiments the method may comprise sealing the entire length of the composite pipe. For example, the method may comprise setting sealing plugs at opposing ends of the composite pipe.

The method may comprise controlling the buoyancy of the composite pipe by flooding, for example partially or fully flooding, at least one region of the composite pipe, for example flooding with seawater. The method may comprise controlling the flooding of the composite pipe by selectively pumping fluid, for example seawater, to and from the composite pipe. Such an arrangement may permit the buoyancy of the composite pipe to be dynamically adjusted.

The method may comprise defining one or more chambers within the composite pipe and selectively flooding said one or more chambers. The method may comprise dynamically modifying the one or more chambers. For example, the method may comprise varying the position of one or more chambers along the length of the pipe.

The method may comprise varying the volume of one or more chambers. Such an arrangement may permit any free surface effects to be minimised, for example by modifying the volume of one or more chambers to eliminate any internal free surfaces. The method may comprise providing at least one pig device or tool within the composite pipe and moving said pig axially along said pipe to dynamically alter the internal chamber.

The composite pipe may comprise multiple chambers, and the method may comprise selectively flooding one or more of said chambers. The method may comprise displacing fluid from one chamber to another chamber.

The method may comprise coupling one or more hydrodynamic surfaces or structures to the composite pipe. A single hydrodynamic control surface may be provided. Alternatively, multiple hydrodynamic control surfaces may be provided.

The hydrodynamic control surface or structure may comprise streamlining surfaces, for example to minimise drag forces on the composite pipe during movement through a body of water.

The hydrodynamic control surface or structure may comprise a directional control surface, such as a rudder assembly, stabiliser assembly or the like.

The hydrodynamic control surface or structure may comprise at least one hydrodynamic lift structure. Such a hydrodynamic lift structure may permit hydrodynamic lift to be generated during movement of the composite pipe through a body of water. The hydrodynamic lift structure may be arranged to generate upward lift on the composite pipe. The hydrodynamic lift structure may be arranged to generate downward lift on the composite pipe.

The hydrodynamic control surface or structure may comprise one or more hydrofoils.

The hydrodynamic control surface or structure may comprise one or more fins. The hydrodynamic control surface or structure may comprise one or more chains suspended form the composite pipe.

The method may comprise manipulating the composite pipe to transport said pipe to a desired marine location. The desired marine location may define an end use location of the composite pipe, for example a service location. Alternatively, the desired marine location may be an intermediate location. For example, the intermediate location may define a loading or pick-up location, at which the composite pipe may be assigned or transferred to another handling system, such as a conventional marine vessel, ship, rig structure or the like. The method may comprise assigning or transferring the composite pipe to another handling system.

The method may comprise transporting the composite pipe from a manufacturing location to a desired marine location.

Once at the desired marine location the autonomous marine drive unit may be decoupled from the composite pipe. Alternatively, in some embodiments the autonomous marine drive unit may remain coupled to the composite pipe when said pipe is at its desired marine location. For example, the marine drive unit may be disposable. Alternatively, the marine drive unit may function during service of the composite pipe, for example to assist with station keeping of the composite pipe. In some embodiments the autonomous marine drive unit may function to assist to maintain a desired configuration, for example shape or geometry, of the composite pipe when in service. For example, the autonomous marine drive unit may assist to define and/or maintain a riser form, such as a catenary riser form, wave catenary form, or the like.

The method may comprise using the autonomous marine drive unit to manipulate the composite pipe into a desired deployment orientation. For example, the method may comprise manipulating the composite pipe to be moved from a generally horizontal orientation to a generally vertical orientation, for example to be used as a marine riser. In one embodiment a first autonomous marine drive unit may be located at one end region of the composite pipe and a second autonomous marine drive unit may be located at an opposite end region of the composite pipe. In such an arrangement one of the first and second autonomous drive units may be used to drive the associated end region of the composite pipe downwardly, and the other of the first and second autonomous drive units may be used to maintain the associated opposite end region either at a fixed height within the body of water, or alternatively drive said associated opposite end upwardly.

The method may comprise manipulating the composite pipe via the autonomous marine drive unit to position said composite pipe in a storage configuration, for example a parked configuration. Such an arrangement may permit the composite pipe to be stored for later handling, for example subsequent installation, for example by a manned vessel. In one embodiment the method may comprise manipulating the composite pipe via the autonomous marine drive unit to position the composite pipe on the seabed.

The method may comprise transporting material within or on the composite pipe. For example, the pipe may be loaded, for example internally and/or externally, with a material which is to be delivered to an offshore location. Such a material may comprise, for example, tooling, equipment, fluids, such as drilling mud, completion fluid, fracturing fluid, proppant or the like.

The method may comprise manually operating the autonomous marine drive unit, for example directly manually controlling remotely controlling or the like. The method may comprise overriding an autonomous operation such that manual operation is permitted. In one embodiment the method may comprise manually operating the marine drive unit during a desired period. The desired period may comprise an initial launch period of the composite pipe. The desired period may comprise a period during which the composite pipe nears or reaches a target location. The desired period may comprise a period during which the composite pipe is installed at a target location.

In one embodiment the method may comprise autonomously controlling the marine drive unit to drive the composite pipe towards a target location, and subsequently manually operating the marine drive unit, for example to manually control final stages of approach to a target location, manually control some aspects of installation of the composite pipe or the like.

The matrix material of the pipe may comprise a polymer. The matrix material may comprise a thermoplastic component. The matrix material may comprise a thermoset component. The matrix material may comprise a polyaryl ether ketone, a polyaryl ketone, a polyether ketone, a polyether ether ketone, a polycarbonate or the like, or any suitable combination thereof. The matrix material may comprise a resin, such as an epoxy resin or the like.

The reinforcing fibres may comprise continuous or elongate fibres. The reinforcing fibres may comprise any one or combination of carbon, glass, polymer, basalt, aramid fibres or the like.

The composite material construction may permit the pipe to be lighter, for example significantly lighter, than a metallic pipe equivalent. In some embodiments the composite pipe may be around 1/10th of the weight of an equivalent steel pipe structure. This may facilitate the use of an autonomous marine drive unit to manipulate the composite pipe. This may avoid or minimise the requirement for use of specialised vessels and associated crew which might otherwise be necessary for metallic pipe structures.

The composite pipe may have a high temperature capability, for example up to 200 degrees C (and possibly higher). The composite pipe may have corrosion resistance to various chemicals and compositions, such as seawater, hydrogen sulphide, carbon dioxide and the like. The composite pipe may define a high pressure capability, for example up to 1380 bar (and possibly higher). The composite pipe may have a high fatigue capability, high strain capability, high tension capability or the like.

The composite pipe may comprise pipe sold by the present applicant under the name m-pipe (trade mark).

The composite pipe may be a subsea pipe, for example intended to be deployed and operated in a subsea environment. The composite pipe may be a subterranean pipe, for example intended to be deployed and operate in a subterranean environment, for example within a wellbore.

The composite pipe may be for use in offshore oil and gas exploration and/or production operations. The composite pipe may be an oilfield tubular. The composite pipe may define an internal bore for communication of fluid and/or apparatus therethrough. The composite pipe may comprise a connector at one or both ends thereof to permit connection with another structure, such as a flow system.

The composite pipe may comprise or be intended to define a marine riser. In such an arrangement the method may comprise deploying a marine riser.

The composite pipe may comprise a flowline, jumper, spool, injection conduit, production conduit, hydraulic control conduit, intervention conduit or the like.

In some embodiments the composite pipe may be extended and manipulated when generally longitudinally extended. In some embodiments at least a portion of the composite pipe may be spooled.

The composite pipe may be of any length. For example, the composite pipe may between 10 and 10,000 meters long, for example between 10 and 5,000 meters long, for example around 10 meters in length, around 100 meters in length, around 500 meters in length, around 1,000 meters in length, around 5,000 meters in length, or the like.

The composite pipe may comprise a single length of pipe. Alternatively, the composite pipe may comprise multiple pipe sections connected together, for example in end to end relation.

The method may comprise coupling the autonomous marine drive unit to a single composite pipe. Alternatively, the method may comprise coupling the autonomous marine drive unit to multiple composite pipes, for example arranged in a pipe bundle, such as arranged side-by-side in a pipe bundle.

The marine environment may comprise any body of water, such as an ocean, sea, river, lake or the like.

An aspect or embodiment relates to a pipe deployment apparatus, comprising an autonomous marine drive unit configured to be coupled to a composite pipe having a wall comprising a matrix material and a plurality of reinforcing fibres embedded within the matrix material.

An aspect or embodiment related to an autonomous marine drive unit configured to be coupled to a composite pipe having a wall comprising a matrix material and a plurality of reinforcing fibres embedded within the matrix material.

An aspect or embodiment relates to a pipe system, comprising: a composite pipe having a wall comprising a matrix material and a plurality of reinforcing fibres embedded within the matrix material; and an autonomous marine drive unit coupled to the composite pipe.

Other aspects or embodiments may relate to autonomous pipe deployment systems and apparatus and autonomous pipe deployment methods.

An aspect or embodiment relates to a method, comprising: coupling an autonomous marine drive unit to a pipe; and operating the autonomous marine drive unit to manipulate the pipe within a marine environment.

The pipe may comprise a metallic pipe. Alternatively, the pipe may comprise a composite pipe.

An aspect or embodiment relates to a pipe deployment apparatus, comprising an autonomous marine drive unit configured to be coupled to a pipe.

An aspect or embodiment relates to an autonomous marine drive unit configured to be coupled to a pipe.

An aspect or embodiment relates to a pipe system, comprising: a pipe; and an autonomous marine drive unit coupled to the pipe.

An aspect or embodiment relates to a pipe buoyancy control system, comprising a pig apparatus mountable within a pipe and being moveable therein to vary the volume of a fluid chamber.

The pipe buoyancy control system may be utilised during manipulation, for example transportation, of the pipe.

The pig apparatus may be moveable within the pipe to control free surface effects of fluids within the pipe. For example, the pig apparatus may be moveable within the pipe to modify a fluid chamber to be substantially completely filled by fluid, thus eliminating any free surface within the pipe.

The pig apparatus may be removable from the pipe, for example when the pipe has been transported to its required location.

It should be understood that features defined in relation to one aspect may be provided in combination with any other aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic illustration of an embodiment of an autonomous pipe deployment method and apparatus; Figure 2 is a diagrammatic illustration of an alternative embodiment of an autonomous pipe deployment method and apparatus; Figure 3 is a diagrammatic illustration of an alternative embodiment of an autonomous pipe deployment method and apparatus; Figure 4 is a diagrammatic illustration of an alternative embodiment of an autonomous pipe deployment method and apparatus; Figure 5 is a diagrammatic illustration of an alternative embodiment of an autonomous pipe deployment method and apparatus; Figure 6 is a diagrammatic illustration of an alternative embodiment of an autonomous pipe deployment method and apparatus; Figures 7A-7C are diagrammatic illustrations sequential stages of deploying a composite pipe in accordance with one embodiment; and Figures 8A-8C are diagrammatic illustrations sequential stages of deploying a composite pipe in accordance with an alternative embodiment.

DETAILED DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention provide apparatus and methods for the autonomous deployment of pipes, such as composite pipes offshore. Numerous arrangements are possible, some of which will be described below, for exemplary purposes only. In each of the example embodiments described the pipe being deployed is a composite pipe having a pipe wall which comprises a composite material, in particular a composite material formed from a matrix and a plurality of reinforcing fibres embedded with the matrix. The pipe may be m-pipe (trade mark) sold by the present applicant.

The composite pipe may be for use in offshore oil and gas exploration and/or production operations. The composite pipe may be an oilfield tubular. For example, the pipe may comprise or be intended to define a marine riser, flowline, jumper, spool, injection conduit, production conduit, hydraulic control conduit, intervention conduit or the like. Furthermore, the composite pipe may be of any length. For example, the composite pipe may between 10 and 10,000 meters long, for example between 10 and 5,000 meters long Figure 1 diagrammatically illustrates a composite pipe 10 which is coupled at a first end 12 thereof to a first unmanned autonomous surface vessel (ASV) 14 via a first tether line 16. The first ASV 14 defines or includes a first autonomous marine drive unit 18 which in the embodiment shown includes a thruster in the form of a propeller. A second, opposite end 20 of the composite pipe 10 is coupled to a second unmanned ASV 22 via a second tether line 24. The second ASV 22 is similar to the first ASV 14 and as such includes or defines a second autonomous marine drive unit 26 which in the embodiment shown also includes a thruster in the form of a propeller.

The first and second ASVs 14, 22 and their associated drive units 18, 26 are autonomously controlled, and as such do not require any human intervention, providing significant advantages in terms of the size of the vessels and the required operational costs. Such autonomous control may comprise use of satellite navigation systems, radar systems, sonar system and the like. In this respect each ASV 14, 22 includes a respective antenna 15, 23 which may be used for receiving and/or transmitting position data, and/or for providing communication between the ASVs 14, 22.

The buoyancy of the pipe 10 is controlled such that it floats on the surface 28 of a body of water 30. Such buoyancy may be controlled by sealing the pipe 10 at the opposing first and second ends 12, 20, such that the pipe 10 is air filled and is prevented from filling with water. Further, the nature of the composite material which forms the wall of the pipe 10 may facilitate or provide a lighter structure, for example perhaps around 1/10th of the in-water weight of an equivalent steel pipe.

The first and second ASVs 14, 22, and their associated drive units 18, 24 may thus be used to autonomously manipulate, for example drive, the pipe 10 across the water surface 28. This may allow the pipe 10 to be autonomously transported across the water surface 28 to a desired offshore location. Alternatively, such an arrangement may allow the pipe 10 to be autonomously transported to an onshore location, for example to a defined port, harbour or the like.

Manipulating the pipe 10 on the water surface 28 may expose the pipe 10 to cyclical loading, for example due to wave motion. Such cyclical loading may be accommodated by the nature of the composite material of the pipe 10, for example by virtue of its higher strain capabilities and resistance to fatigue compared to an equivalent metallic pipe.

In an alternative embodiment, as illustrated in Figure 2, a pipe, in this case identified by reference numeral 40, is also coupled to first and second ASVs 42, 44 which include respective first and second autonomous marine drive units 46, 48. ASVs 42, 44 may be similar to ASVs 14, 22 of Figure 1 and as such no further description will be given.

In the present embodiment the buoyancy of the pipe 40 is controlled such that the pipe 40 is submerged below the surface 28 of the body of water, and thus is isolated, to a large degree, from the effects of surface wave motion. The buoyancy of the pipe 40 may be controlled by selectively flooding one or more chambers within and along the pipe 40.

In some instances fluid located internally within the pipe 40 may move therein in response to changes in the attitude of the pipe. This is known as a free surface effect, and could modify the centre of gravity of the pipe, which may cause undesired movement, for example sinking of one portion and upward movement of another portion. This may apply unwanted strain on the pipe 40, and potentially provide undesired loading on the ASVs 42, 44. To address this the pipe 40 includes an internal control system, in the form of one or more pipe pigs 50, shown in the enlarged view of a section of the pipe 40 in Figure 2. This pig 50, optionally in combination with other pigs (not shown) may move axially along the pipe 40 to vary the volume of any fluid containing internal chamber, for example to permit the chamber to be substantially completely filled, and thus eliminate or minimise any free surface. Alternatively, or additionally, free surfaces may be permitted within the pipe 40, wherein the pig 50 (or pigs) may move to counteract any variations in the centre of gravity caused by any free surface.

A modified embodiment is illustrated in Figure 3, in which a submerged pipe 60 is coupled to first and second ASVs 62, 64 which include respective first and second autonomous marine drive units 66, 68. ASVs 62, 64 may be similar to ASVs 14, 22 of Figure 1 and as such no further description will be given. In the present embodiment the pipe 60 includes a number of hydrodynamic structures or fins 70. When the pipe 60 is driven by the ASVs 62, 64 a hydrodynamic lift force is generated on the fins 70.

In the embodiments shown in Figures 1 to 3 the respective pipes are secured to their ASVs via tether lines. However, in other embodiments, as illustrated in Figure 4, a pipe 70 is directly mounted on an secured to first and second ASVs 72, 74.

A further alternative embodiment is illustrated in Figure 5, reference to which is now made. In this embodiment individual autonomous marine drive units 80, 82, 84 are directly mounted, for example by clamping, to a pipe 86 which is arranged to float on the water surface 28. Accordingly, associated ASVs are not required, with the pipe 86 functioning as a vessel. In the embodiment shown the drive units 80, 82, 84 are azimuth thrusters, which provide thrust and directional control.

Figure 6 provides a further alternative embodiment in which a pipe 90 is configured to be submerged below the water surface 28, wherein a first end 92 of the pipe 90 is directly connected to a first autonomous underwater drive vehicle 94 which includes or defines an autonomous marine drive unit. A second opposite end 96 of the pipe 90 is directly connected to a second autonomous underwater drive vehicle 98 which includes or defines an autonomous marine drive unit.

In the embodiment of Figure 6 the pipe 90 may be autonomously manipulated by appropriate control of the first and second autonomous underwater drive vehicles 94, 98.

In the embodiments described above pipes, for example composite pipes, may be autonomously transported to a desired offshore location. When the desired location is reached the use of the various autonomous vehicles may be complete. However, in some instances the autonomous vehicles may be used to provide further manipulation of the pipes.

For example, Figure 7A illustrates the same pipe 90 of Figure 6 reaching a desired location under the control of the first and second autonomous underwater drive vehicles 94, 98. Once at the required location the vehicles 94, 98 drive the pipe 90 downwardly, as illustrated in Figure 7B, to ultimately position the pipe 90 on the seabed 100 as shown in Figure 7C. In this case the pipe 90 may be wet-parked on the seabed 100. The pipe 90 may be stored in this parked position ready for later installation by, for example, a manned vessel.

In an alternative arrangement the same pipe 90 of Figure 6 may again reach the desired location, as illustrated in Figure 8A, under control of the first and second autonomous underwater drive vehicles 94, 98. However in this embodiment, as illustrated in Figure 8B, the first autonomous underwater drive vehicle 94 drives the first end 92 of the pipe 90 downwards, while the second autonomous underwater drive vehicle 98 moves the second end 96 of the pipe 90 to become positioned vertically above the first end 92, as illustrated in Figure 8C, thus manoeuvring the pipe 90 into a vertical orientation. Such an arrangement may be of use where the pipe 90 defines a marine riser, for example.

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. For example, any number of autonomous drive units may be mounted or otherwise connected along the length of a pipe, including a single unit or multiple units. Furthermore, in each of the embodiments shown a single pipe is illustrated. However, in other embodiments multiple pipes may be manipulated simultaneously.

For example multiple pipes in a pipe bundle may be autonomously manipulated.

Also, in some embodiments manual control may be permitted. For example, methods may comprise autonomously controlling the marine drive unit or units to drive the composite pipe towards a target location, and subsequently manually operating the marine drive unit, for example to manually control final stages of approach to a target location, manually control some aspects of installation of the composite pipe or the like.

Claims

CLAIMS: 1. A method, comprising: coupling an autonomous marine drive unit to a composite pipe having a wall comprising a matrix material and a plurality of reinforcing fibres embedded within the matrix material; and operating the autonomous marine drive unit to manipulate the composite pipe within a marine environment.
2. The method according to claim 1, comprising autonomously operating the autonomous marine drive unit.
3. The method according to claim 1 or 2, wherein the autonomous marine drive unit comprises an autonomous control system for providing autonomous control of the marine drive unit, wherein the method comprises operating the autonomous marine drive unit under the control of the autonomous control system.
4. The method according to any preceding claim, wherein the autonomous marine drive unit comprises a thrust arrangement for generating thrust.
5. The method according to claim 4, wherein the autonomous marine drive unit comprises a drive source operationally connected to a thrust arrangement.
6. The method according to any preceding claim, wherein the autonomous marine drive unit comprises a direction control arrangement.
7. The method according to any preceding claim, comprising coupling an autonomous marine azimuth drive unit to the composite pipe.
8. The method according to any preceding claim, comprising coupling the composite pipe to an autonomous marine vessel which includes the autonomous marine drive unit.
9. The method according to claim 8, wherein the marine vessel is at least one of an autonomous surface vessel and an autonomous underwater vehicle.
10. The method according to any preceding claim, comprising directly mounting the autonomous marine drive unit to the composite pipe.
11. The method according to any preceding claim, comprising coupling a single autonomous marine drive unit to the composite pipe.
12. The method according to any one of claims 1 to 10, comprising coupling multiple autonomous marine drive units to the composite pipe.
13. The method according to any preceding claim, comprising manipulating the composite pipe on the surface of a body of water.
14. The method according to any preceding claim, comprising arranging the composite pipe to float on the surface of a body of water, to permit manipulation of the composite pipe on the surface of the body of water.
15. The method according to any preceding claim, comprising manipulating the composite pipe below the surface of a body of water.
16. The method according to any preceding claim, comprising submerging the composite pipe within a body of water, to permit manipulation of the composite pipe below the surface of the body of water.
17. The method according to any preceding claim, comprising controlling the buoyancy of the composite pipe to permit said pipe to at least one of float on a body of water and to be submerged into a body of water.
18. The method according to any preceding claim, comprising controlling the buoyancy of the composite pipe by sealing one or more regions along the length of the composite pipe, such that said one or more sealed regions may be gas filled.
19. The method according to any preceding claim, comprising controlling the buoyancy of the composite pipe by flooding at least one region of the composite pipe.
20. The method according to claim 19, comprising defining one or more chambers within the composite pipe and selectively flooding said one or more chambers.
21. The method according to claim 19 or 20, comprising providing at least one pig device or tool within the composite pipe and moving said pig axially along said pipe to accommodate free surface effects.
22. The method according to any preceding claim, comprising coupling one or more hydrodynamic surfaces or structures to the composite pipe.
23. The method according to any preceding claim, comprising manipulating the composite pipe to transport said pipe to a desired marine location.
24. The method according to claim 23, comprising operating the autonomous marine drive unit to manipulate the composite pipe at the desired marine location.
25. The method according to claim 23 or 24, comprising operating the autonomous marine drive unit to manipulate the composite pipe into a desired deployment orientation.
26. The method according to claim 23, 24 or 25, comprising manipulating the composite pipe to be moved from a generally horizontal orientation to a generally vertical orientation.
27. The method according to any one of claims 23 to 26, comprising manipulating the composite pipe at the desired marine location via the autonomous marine drive unit to position said composite pipe in a storage configuration.
28. The method according to any preceding claim, comprising coupling the autonomous marine drive unit to a single composite pipe.
29. The method according to any one of claims 1 to 27, comprising coupling the autonomous marine drive unit to multiple composite pipes arranged in a pipe bundle.
30. The method according to any preceding claim, comprising manually controlling the autonomous marine drive unit.
31. The method according to any preceding claim, comprising manually overriding autonomous control of the autonomous marine drive unit.
32. A pipe deployment apparatus, comprising an autonomous marine drive unit configured to be coupled to a composite pipe having a wall comprising a matrix material and a plurality of reinforcing fibres embedded within the matrix material.
33. An autonomous marine drive unit configured to be coupled to a composite pipe having a wall comprising a matrix material and a plurality of reinforcing fibres embedded within the matrix material.
34. A pipe system, comprising: a composite pipe having a wall comprising a matrix material and a plurality of reinforcing fibres embedded within the matrix material; and an autonomous marine drive unit coupled to the composite pipe.
35. A method, comprising: coupling an autonomous marine drive unit to a pipe; and operating the autonomous marine drive unit to manipulate the pipe within a marine environment.
36. A pipe deployment apparatus, comprising an autonomous marine drive unit configured to be coupled to a pipe.