GB2561196A

GB2561196A - Subsea pipeline buoyancy module

Info

Publication number: GB2561196A
Application number: GB1705433.9A
Authority: GB
Inventors: Morand Henri; Daniell Richard
Original assignee: Technip France SAS
Current assignee: Technip Energies France SAS
Priority date: 2017-04-04
Filing date: 2017-04-04
Publication date: 2018-10-10
Anticipated expiration: 2037-04-04
Also published as: GB2561196A8; GB2561196B; GB201705433D0

Abstract

A subsea pipeline buoyancy module 2 comprising monitoring apparatus 4 to monitor a condition or parameter of the buoyancy module. The monitoring apparatus is accessible for e.g. data storage removal by a subsea diver or a ROV via e.g. a pod hole 8 with funnel entry 12 closed by a plug 14 to protect from marine life, and includes a power supply 26 or power generation unit and sensors 20. The monitoring apparatus can monitor a condition or parameter of the buoyancy module on land, during subsea testing, and/or during subsea use, such as depth, temperature, salinity, foam curing, slamming load, motion, pressure, acoustic, optical, visual, stress, strain, tension. The power source may be one of a water activated, induction rechargeable and an LiSi/CoS2 battery, a seawater cell, an open or ducted turbine or a fin generator. The sensors may involve Surface Acoustic Wave array, a time lapse camera, or an attitude sensor. The module may be a two half-shell type joined by a metallic or elastomer clamp which may be monitored for condition.

Description

(71) Applicant(s):

Technip France (Incorporated in France)

6-8 AHee de I'Arche,

Faubourg de L*Arche - Zac Danton,

92400 Courbevoie,

France (including Overseas Departments and Territori es) (72) Inventor(s):

Henri Morand Richard Daniell (74) Agent and/or Address for Service:

Murgitroyd & Company

Scotland House, 165-169 Scotland Street, GLASGOW, G5 8PL, United Kingdom (51) INT CL:

E21B 17/01 (2006.01) F16L 1/24 (2006.01) (56) Documents Cited:

EP 2985502 A WO 2012/156681 A

US 4399601 A KR 20130097257 JPH04322115 (58) Field of Search:

INT CL E21B, F16L

Other: WPI, EPODOC Patent Fulltext (54) Title of the Invention: Subsea pipeline buoyancy module

Abstract Title: Subsea pipeline buoyancy module with monitoring apparatus (57) A subsea pipeline buoyancy module 2 comprising monitoring apparatus 4 to monitor a condition or parameter of the buoyancy module. The monitoring apparatus is accessible for e.g. data storage removal by a subsea diver or a ROV via e.g. a pod hole 8 with funnel entry 12 closed by a plug 14 to protect from marine life, and includes a power supply 26 or power generation unit and sensors 20. The monitoring apparatus can monitor a condition or parameter of the buoyancy module on land, during subsea testing, and/or during subsea use, such as depth, temperature, salinity, foam curing, slamming load, motion, pressure, acoustic, optical, visual, stress, strain, tension. The power source may be one of a water activated, induction rechargeable and an LiSi/CoS2 battery, a seawater cell, an open or ducted turbine or a fin generator. The sensors may involve Surface Acoustic Wave array, a time lapse camera, or an attitude sensor. The module may be a two half-shell type joined by a metallic or elastomer clamp which may be monitored for condition.

FIG. 1

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

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FIG. 2

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CATHODE ANODE

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FIG. 7

SUBSEA PIPELINE BUOYANCY MODULE

Technical Field

The present invention relates to a subsea pipeline buoyancy module which can be attached or fitted to a pipeline, as well as monitoring apparatus therefor.

Background

Traditionally, subsea pipelines are laid between a seabed and a surface or near surface structure or vessel, and one or more buoyancy modules are added thereto to assist achieving intended buoyancy of the pipeline thereinbetween, sometimes to achieve a certain configuration for the pipeline, or to assist its particular position or arrangement with other infrastructure or subsea items.

Subsea buoyancy modules are well known in the art, and typically have a defined amount or element of buoyancy. Some buoyancy modules are based on having one or more air or other gas enclosures. Other buoyancy mediums exist, including polyurethane foam and materials such as syntactic foam, typically within a resin or other packing or containing material, with an outer harder encasement to resist damage to the buoyancy module in use. Reinforcement materials may be useable such as fibreglass, but it is typically intended that the buoyancy modules are relatively simple structures in order to be robust, whilst easily replaceable.

Typically, a buoyancy module is attached to a pipeline either by having a central tubular aperture through which the pipeline passes, or being formed by one or more portions such as half-shells, which can be secured, for example by mean of a clamp, around the pipeline, and typically fastened thereto by one or more bands or straps, in a manner known in the art.

Buoyancy modules undergo the full range of undersea conditions, including shifting sea currents, as well as problems caused for example by marine growth attaching to the pipeline or the buoyancy module, and general wear and tear. Whilst some buoyancy modules may be easily replaceable, generally at shallow depths, buoyancy modules are being used at increasing depths below 500 metres, or 1000 metres, or deeper, where replacement of a buoyancy module involves increased complexity and undesired costs.

It is also now desired for buoyancy modules to remain in condition or ‘operational’ for the same service life as the pipeline.

Summary

According to one aspect of the present invention, there is provided a subsea pipeline buoyancy module comprising monitoring apparatus to monitor a condition or parameter of the buoyancy module.

According to a second aspect of the present invention, there is provided a method of monitoring a condition or parameter of a subsea pipeline buoyancy module. This comprises a step of operating a monitoring apparatus as defined herein being part of a buoyancy module.

According to a third aspect of the present invention, there is provided a monitoring apparatus as defined herein for monitoring a condition or parameter of a subsea pipeline buoyancy module as defined herein.

Description of the drawings

Figure 1 is a perspective view of a subsea pipeline buoyancy module according to one embodiment of the present invention;

Figure 2 is a part cutaway view a subsea pipeline buoyancy module according to another embodiment of the present invention being interrogated by a subsea diver; Figure 3 is a perspective view of one part of a two-part subsea pipeline buoyancy module according to another embodiment of the present invention;

Figure 4 is a perspective view of the application of the buoyancy module part shown in figure 3 and a complementary part on a subsea pipeline;

Figure 5 is a perspective view of a subsea pipeline buoyancy module according to other embodiments of the present invention;

Figure 6 is a schematic view of a subsea pipeline comprising a number of subsea pipeline buoyancy modules according to an embodiment of the present invention: and

Figure 7 is a simple illustration of a seawater battery useable with a subsea pipeline buoyancy module.

Detailed description of the drawings

In one aspect, the present invention relates to a subsea pipeline buoyancy module comprising monitoring apparatus to monitor a condition or parameter of the buoyancy module.

Subsea buoyancy modules are used in increasingly stringent conditions, such as deeper water depths and higher temperatures, and are desired to have a longer service life, optionally the service life of the pipeline itself. As such, monitoring of the buoyancy module assists to reduce the risks associated with any deterioration, malfunction or non-function of the buoyancy module.

The invention also allows monitoring of a condition or parameter of a subsea buoyancy module on land or on shore prior to its deployment subsea, in particular during its testing such as qualification testing, or during its manufacturing process.

A subsea pipeline buoyancy module can have any size, colour, shape and design, and typically the most important parameter is buoyancy. A buoyancy module can be formed of one or more compartments. Typically, the buoyancy module has a central aperture for the location of a pipeline therethrough. Typically, a buoyancy module is wholly or substantially cylindrical, and wholly or substantially symmetrical.

The subsea buoyancy module can be formed of a singular material or a plurality of materials, and may comprise one or more layers, in particular an outer layer or shell intended to be robust or protective.

Buoyancy for a subsea pipeline buoyancy module can be provided by a gas, typically air but not limited thereto, optionally within or part of a foam or foam material or multiple foams or foam materials, forming the majority of the subsea pipeline buoyancy material.

Various foam or foam materials are known in the art to provide buoyancy, an example of which is a syntactic foam. Syntactic foam is a term used to refer to a range of foam materials comprising a polymer resin loaded with hollow microspheres. The micro-spheres serve to reduce the overall density of the polymer resin and provide the necessary buoyancy of the foam material. The properties of the syntactic foam may be modified by varying the composition of the polymer resin and by varying the size and number of the micro-spheres incorporated into the resin material. Typically, a buoyancy module comprising syntactic foam has an outer layer capable of resisting damage and providing strength. The outer layer may comprise a reinforcing material, such as fibreglass or other glass reinforced polyesters or elastomers.

Optionally, the monitoring apparatus is integral with the buoyancy module. That is, the monitoring apparatus can be formed in, around, or as a part of the buoyancy module during its manufacture, and optionally permanently attached with an adhesive to the buoyancy module. In one example, one or more materials such as a foam material used to form the buoyancy module are at least partly formed around the monitoring apparatus whilst providing the necessary access thereto.

Optionally, the monitoring apparatus is attachable to the buoyancy module. That is, the monitoring apparatus can be fitted, optionally retro-fitted, to the already formed buoyancy module. The attachment can be by way of locating the monitoring apparatus internally, externally or a combination of internally and externally to the buoyancy module, and in a manner to achieve permanent attachment or temporary attachment of the monitoring apparatus to the buoyancy module.

In one embodiment, one or more apertures, spaces or holes can be formed in the buoyancy module after manufacture, for the location of a monitoring apparatus wholly or partly therein. Optionally after testing the monitoring apparatus, such monitoring apparatus can be attached by the use of one or more fixing means including bolts, screws, adhesives, resins, straps or other fixing means, to maintain the monitoring apparatus within the or each relevant aperture, space, etc. Such fixing means can include glue or polyurethane.

Optionally, the monitoring apparatus is accessible by a user for inspection, and optionally interrogation. The user may be any suitable person or device, and includes a subsea diver or a Remotely Operated Vehicle (ROV) when the buoyancy module is underwater.

Optionally, one or more apertures are formed in the buoyancy module to access the monitoring apparatus. In particular, where the monitoring apparatus is wholly or substantially located within the outer surface of the buoyancy module, and direct access is required thereto either to assist the monitoring apparatus or to interrogate the monitoring apparatus for collected data, reasonably easy access thereto (within the parameters of any subsea operation) is preferred, unless remote interrogation of the monitoring apparatus is possible as discussed hereinafter.

Optionally, the or one aperture formed in the buoyancy module to access the monitoring apparatus is a pod hole. The pod hole can be formed in the module itself, and can be designed and manufactured in such a way that the monitoring apparatus can be inserted and locked in place by the subsea diver or ROV. A locking mechanism, for example a spring loaded or a subsea latching mechanism, can be provided in the module itself or it can be incorporated onto the monitoring apparatus.

Optionally, the or one aperture formed in the buoyancy module has a funnel entry. A funnel entry allows easier access for docking with the aperture, for a pod or the like or for access by a subsea diver or a ROV.

Optionally, the or one aperture formed in the buoyancy module can be closed, and preferably sealed. Preferably, the or one aperture has a sealing, preferably a reversible sealing, such that the or one aperture can be moved between at least open and closed positions. An open position can be to allow access to or through the or one aperture. A closing position can be where such access is not required, and in order to create a barrier between the access point or monitoring apparatus and the sea.

Optionally, the sealing of the aperture can be by a flap or plug or stop, able to form a seal on, in or within the or one aperture, either by its removal or by its movement in relation to the aperture. In one example, a subsea diver or ROV can remove a plug in order to gain access into an aperture formed in the buoyancy module, to access the monitoring apparatus, either for retrieving data, interrogating the monitoring apparatus and/or removal of the monitoring apparatus.

Optionally, the subsea pipeline buoyancy module comprises a power supply. The power supply powers the monitoring apparatus.

In one arrangement, the power supply is provided along the subsea pipeline or from within the subsea pipeline. In one embodiment, a powerline can be provided from a floating vessel e.g. from a power generator or generation unit on the floating vessel, so that there is security of the power line taking the path of the subsea pipeline and directly meeting the buoyancy module. In such an arrangement, data concerning one or more conditions or parameters of the buoyancy module could be transmitted and/or supplied to a remote unit or collector along such power supply path.

In an alternative embodiment, the subsea pipeline includes a power line for another purpose, such as being a service umbilical providing power to one or more subsea units in a manner known in the art, and a power supply can be extended from the power line in the pipeline at or near the buoyancy module by an extension or branch thereof. By way of example only, at any junction or conjunction of a section of the pipeline either to another section (to create a longer pipeline in a manner known in the art), or to an intermediate apparatus, device or unit, such as an in-line structure (ILS), where a suitable port or path for a branch power line from an internal power line in the pipeline can be easily provided, which branch line can then be rooted to the buoyancy module, possible partly along the outside of the subsea pipeline between such join and the buoyancy modules.

In another arrangement, the power supply is provided on the buoyancy module, or additionally or alternatively in the buoyancy module. In one embodiment, the power supply is a battery or at least one battery, and optionally the subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring device is powered by one or more of the group comprising; a wateractivated battery, a rechargeable battery such as an induction rechargeable battery, and a LiSi/CoS2 battery.

Battery technology is well known in the art, and in the present invention, one or more batteries can be located on or in the buoyancy module.

One example of a suitable battery for use in the present invention uses seawater as the electrolyte, based on having a cathode and anode wherein seawater is accessible therein between, and the anode and cathode are sized to last for the service life of the buoyancy module. One or more cut outs could be provided on the buoyancy module for suitable location of the cathode and anode, and wateractivated batteries can also act as reserve batteries.

In a further embodiment of the present invention the buoyancy module could comprise a subsea pipeline buoyancy module comprising one or more of the group comprising: a module motion power generation unit, a subsea temperature differential power generation unit, a flexible fin power generation unit and a hydro turbine power generation unit.

For example, a buoyancy module could be fitted with a flexible fin system comprising one or more fins extending from the buoyancy module outwardly, typically transversely from a side of the buoyancy module, such that each time the fin is displaced by the surrounding water, motion creates power for powering the buoyancy module.

In alternative arrangement, the buoyancy module comprises a hydro turbine, wherein turbine is able to work on a side of the buoyancy module, or even by use of a through hole in the buoyancy module through which water can flow and create movement of a turbine to generate power. Other devices are known in the art for translating motion and/or movement of a subsea device into power, including the use of a blade or blades, or propeller or the like, attachable to a suitable power generation unit which can be located within the buoyancy module.

Optionally, any power generation unit or part thereof to be part of the buoyancy module can be suitably located or housed in or next to the buoyancy module prior to use, and in particular prior to launch of the buoyancy module, prior to an active disposition position once the buoyancy module is wholly or substantially in its intended location, such that the launch and positioning of the buoyancy module does not affect any such power generation unit or part thereof.

For example, any external fins or blades or parts can be folded to be flush with the outer surface of the buoyancy module for transportation and launch, followed by their release and active positioning by a diver or ROV once the buoyancy module is in place. In the present invention, the condition or parameter to be monitored may be such as only requiring a low or indeed very low power supply or source, and on an intermittent basis, such that the power supply or source can be of low power with low current drain.

Another suitable module motion power generation unit relies on movement of the buoyancy module relative to the sea, causing movement of a device or unit, which movement or motion can then be translated into electrical power. This can include having an internal turbine in a suitable location within the buoyancy module, including in an elongate tube or aperture through the buoyancy module, as well as the location of an external turbine or propeller or similar, again able to be driven by the motion of the sea relative to the buoyancy module.

A suitable subsea temperature differential power generation unit can rely on various thermo-electric generators known in the art, including those using the Seebeck effect wherein a heat differential between one part of the buoyancy module and another part of the buoyancy module, such as inner and outer surfaces, can be used to produce a current (based on electrons flowing towards the cooler one of two conductors or semi-conductors through an electrical circuit).

The present invention may involve the use of one or more of the above power sources or generating units to power the monitoring apparatus.

Optionally, any such power source or power supply can also supply power to any docking apparatus or equipment, such as an ROV. Such a power supply could recharge an ROV during its connection with the buoyancy module to inspect and/or interrogate its monitoring apparatus.

Optionally, the monitoring apparatus monitors a condition or parameter of the buoyancy module on land, during installation, during subsea testing, and/or during subsea use.

In one arrangement, the monitoring apparatus monitors a condition or parameter of the buoyancy module on land, in particular during one or more of manufacture or testing of the buoyancy module, such as during qualification testing of a new supplier to determine the worthiness of a new supply of buoyancy modules. Access to a power source to supply to the buoyancy module may be easier on land, such that monitoring may be easier to carry out on land. For example, monitoring on a clamp could be in relation to clamp stress or strain, when the assembly (of the module and the clamp) is tested on a steel mandrel. Such testing on land can also be carried out with the buoyancy module placed in a hyperbaric chamber, and can include monitoring bolt tensions or bolt stresses used to secure the buoyancy module to a subsea pipeline, or a mandrel I sample of a subsea pipeline

In another arrangement, the monitoring apparatus monitors a condition or parameter of the buoyancy module during subsea testing, and/or during subsea use. Subsea testing is typically carried out once the buoyancy module is located in place on a subsea pipeline, and can include monitoring bolt tensions or bolt stresses used to secure the buoyancy module to the subsea pipeline.

Monitoring a condition or parameter during subsea use can include a continuing analysis of bolt tension or bolt stresses used to secure the buoyancy module to the subsea pipeline, as well as for example weight variation versus time, height, depth, temperature, seawater conditions including salinity, etc.

The monitoring apparatus could also monitor a condition or parameter of the buoyancy module during launch of the buoyancy module from a floating vessel and into the sea. It is known that the launch of a buoyancy module leads to a “slamming load” on the buoyancy module as it hits the surface of the sea, which can reduce or damage the buoyancy module. Monitoring of a condition or parameter during launch of the buoyancy module can inform the user of any damage caused to the buoyancy module during launch, which may require remediating action or replacement of the buoyancy module prior to use, and avoid a subsequent issue where a damaged buoyancy module had not been noticed or recognised.

The monitoring apparatus could also be a pressure pad located on the lowermost portion or side of the buoyancy module, to register the map of pressure as that portion or side hit the sea during water entry during launch.

Optionally, the monitoring apparatus actively monitors a subsea condition or parameter of the buoyancy module. Such active monitoring may be continuous or periodic, and may be related to a passage of time.

In an alternative, the monitoring apparatus optionally passively monitors a condition or parameter of the buoyancy module. Such monitoring may be only at the request of a third party such as a ROV or subsea diver, or only when a predetermined level of a condition or parameter is reached or approached, such as a certain pressure or buoyancy value.

Optionally, the monitoring apparatus monitors a condition or parameter of the buoyancy module in real time. The monitoring apparatus may include an internal clock or clocks.

In an alternative, the monitoring apparatus optionally periodically monitors a condition or parameter of the buoyancy module. The period may be regular or irregular, typically regularly for a predetermined time period, such can be different for different conditions or parameters. This can extend form e.g. every hour to every day to every week/month/year etc.

The skilled man is aware that different conditions or parameters may make monitoring of the same event in real time and/or periodically different, and the present invention allows the user to select different times and types of monitoring according the nature of the condition or parameter to be monitored.

Optionally, the monitoring apparatus monitors one or more of the group comprising: depth, temperature, salinity, foam curing, slamming load, motion, pressure, acoustic, opticals, visuals, stress, strain, tension.

The monitoring may be carried out using one or more sensors, monitors, cameras, gyroscopes, etc, generally known in the art, including pressure gauges, thermocouples, etc. Typically, the sensing point or head of each such sensor or camera is connected to a central recording and/or recording unit using one or more leads etc.

Optionally, the monitoring apparatus comprises a sensor, linking cable and a gathering unit.

Optionally, the monitoring apparatus comprises one or more thermocouples and/ or optical fibre cables. Optionally, the monitoring apparatus is a monitoring module.

Optionally, the monitoring apparatus comprises or is attached to one or more timelapse cameras, able to take visuals of a part of the buoyancy module, such as to look at marine growth on the buoyancy module over time.

One or more of the conditions and parameters listed herein can help determine such issues as correct buoyancy module deployment, location, positioning, buoyancy, sea conditions and the like, any one of which can change, and any one of which can effect the intended or expected performance of the buoyancy module.

In particular, the condition or parameter can include monitoring stresses in any clamp, strap and/or other fixing means or device used to attach, secure and/or locate the buoyancy module in relation to a subsea pipeline. A typical attachment and securement uses one or more elastomer straps or clamps, and the stress in a rubber segment of the buoyancy module where rubber material is present could be monitored. The stresses in any bolts used for the same or similar purpose could also be monitored, as well as temperature at various interfaces.

Other parameters can include external pressure.

The present invention includes monitoring either an absolute value of a condition or parameter, or variations in a condition or parameters over time, or both.

Optionally, the monitoring apparatus includes an integral data storage means. The data storage means could be any suitable device or unit, including a memory chip or drive unit or similar, whose data can be extracted for analysis by suitable interrogation of the monitoring apparatus.

Interrogation of the monitoring apparatus may be carried out directly or indirectly, and regularly or irregularly, and any combination thereof. Interrogation of the monitoring apparatus may be carried out by a suitable user such as a subsea diver when the buoyancy module is underwater) or unit such as a ROV, having the required complementary unit, device etc to interrogate of the monitoring apparatus.

Additionally, and/or alternatively, the buoyancy module may have one or more separate or separable data storage means, whose removal from the buoyancy module can allow the user to separately interrogate the date on a data storage means in a more convenient location. Removal of a data chip or memory stick or similar device can allow a condition or parameter of the buoyancy module to be later analysed, whilst a replacement device or unit can be inserted into the buoyancy module for continuing monitoring. As such, interrogation of the monitoring apparatus in situ may not be required; only a visit by a suitable user such as a subsea diver when the buoyancy module is underwater) or unit such as a ROV.

Optionally, the pipeline is any suitable pipeline to which one or more buoyancy modules can be added. The present invention is not limited by the nature, size or design of the pipeline, or the known or future deployment of buoyancy modules.

One example of a suitable pipeline is a flexible pipeline, intended to achieve a particular position and/or location or configuration in relation to a surface vessel, a seabed, or a sea surface, or a combination of same. This can include pipelines intended to achieve a particular known configuration, including the wave configuration, as well as location of pipelines to be located in particular relationship to a subsea feature, such as avoiding certain features on a seabed, buckling mitigation., and/or reducing installation loads or the like.

Typically, a subsea pipeline includes one or more layers, optionally with a hydrocarbon transport line or lines therethrough, and typically with one or more outer protective layers. Examples include flowlines, risers, umbilicals and the like, which may be dedicated to run between a particular subsea location or unit and a surface vessel, or may be intended to be part of a subsea system involving a number of subsea pipelines intended to be collected or branched or otherwise interact with one or more other pipelines, in particular in relation to subsea buoyancy stations or meeting hubs.

The present invention is not limited by the nature, size or design of the buoyancy module, and many natures, sizes and designs of buoyancy modules are known in the art. Typically, the buoyancy module is cylindrical or wholly or substantially circular in cross section, and comprises at least an annulus of buoyancy material, with a wholly or substantially open core or central portion therethrough once formed, through which a subsea pipeline can pass. The buoyancy module may be formed as a unitary body, or in portions for subsequent forming. One known arrangement of a buoyancy module comprises two half shells and a clamp, which clamp serves to locate and secure the two half shells of the buoyancy module around a subsea pipeline in a manner known in the art.

The present invention includes monitoring a condition or parameter of the buoyancy module during its manufacture, for example the integrity of a buoyancy module or portion thereof, or the integrity of a clamp, strap etc.

Optionally, the buoyancy module can be defined as including one or more securing straps, clamps or other attachment and securement means to secure the buoyancy module onto the subsea pipeline, and the monitoring apparatus monitors a condition or parameter of the strap or clamp etc.

In particular, a securing clamp may comprise one or more elastomeric elements, having one or more metallic inserts. The use of an elastomeric element in the clamp helps make the clamp more compliant in relation to its use, but the long term behaviour of elastomeric materials such as compressed rubber, in the harsh service conditions that occur subsea, means that monitoring of the condition of the clamp can be an important factor prior to any significant deterioration or indeed breakage of the clamp.

In an example, sensors can be included in an elastomeric element of a securing clamp or strap. The elastomeric element can comprise one or more metallic elements inside rubber one or more blocks used for forming the clamp. The sensors can be of the Surface Acoustic Wave (SAW) type, or be or comprise one or more fibre optical cables, which can be inserted during the manufacturing of the rubber or rubber blocks, or following insertion of a thin metallic tube into the elastomeric elements or clamp once formed, for the insertion of a fibre optic thereinto. After connection ofthe clamp to the buoyancy module, data can be read concerning one or more conditions or parameters of the clamp by a monitoring unit on, in or otherwise attached to the module, which could record the stress/strain and temperature in the rubber, potentially at several locations through its surface and cross section, to determine its condition, and in particular any significant deviation of a parameter to determine a significant changing condition.

Optionally, the buoyancy module has a defined portion such as a flat outer surface portion, to mount the monitoring apparatus. A flat portion on the outer surface of the buoyancy module could be formed either during manufacture of the buoyancy module, or thereafter, such as by machining, to create a flat face for ease of location and attachment of a monitoring apparatus having a flat side. Optionally, the buoyancy module could be altered, such as machined, to include one or more other portions, faces, surfaces or specific shapes adapted to assist either the location or attachment of a monitoring apparatus, or interaction with another device or unit such as a ROV, for ease of access.

Optionally, the buoyancy module is manufactured with a specific location, aperture or space for the location of a monitoring apparatus.

Optionally, the buoyancy module could include one or more handles, to assist a diver or ROV to hold or latch onto the buoyancy module during any inspection or interrogation, or other operation in relation to the present invention. For example, one or more handles could be embedded in the material forming the buoyancy module, such as the foam, which extend beyond the outer surface ofthe buoyancy module once formed, such that the buoyancy material provides sufficient rigidity to maintain the handle in use.

Optionally, material forming the buoyancy material may be such as to allow the formation of one or more further spaces, apertures or locations for one or more sensors, etc. to assist monitoring of a particular parameter or condition.

Optionally, the monitoring apparatus is locked to the buoyancy module. The locking may be by any physical or magnetic means, intended to ensure non-separation of the monitoring apparatus from the buoyancy module irrespective of the conditions the buoyancy module experiences or undergoes.

Optionally, the monitoring apparatus is a self-sufficient and/or a replaceable unit. The replaceable unitwill ensure that once the monitoring operations have taken place, the subsea diver or ROV can retrieve said unit and either insert a new unit (or not any unit). A replaceable unit could allow the use smaller batteries, or monitoring during certain phase of the life of the module, such as for example during the deployment/installation phase.

Optionally, the monitoring unit is for monitoring slamming load during launch of the buoyancy module into the sea from a vessel.

Optionally, the monitoring apparatus is floatable and self releasable from the buoyancy module. Thus, retrieval of the monitoring apparatus may be achievable on a sea surface, rather than requiring a subsea diver or ROV to retrieve the monitoring apparatus or its data from the buoyancy module.

Optionally, the monitoring apparatus comprises a Surface Acoustic Wave (SAW) sensor array. Such sensor array may comprise layered surface acoustic wave sensors, operating at the ‘love’ mode. Layered SAW sensors ensure that the sensor can be operated in a water environment that is the natural environment of a buoyancy module. Passive, remote measuring systems can be created using orthogonal frequency code (OFC) multiplexing techniques. This can achieve cost effective sensing for temperature, pressure and movement monitorings, especially using piezoelectric materials, which may require no batteries, and rely on reflecting measurement signals.

There are typically two primary components used in passive measurement systems, such as a multiple passive SAW sensors, and an active management station, commonly termed an interrogator. During operation, the interrogation station can generate a set of OFC codes, overlaid onto a spread spectrum, wide and radio frequency signal. A SAW device can receive this coded signal via a localised antenna, and the radio signal can then propagate across the device as a surface acoustical wave, which generates a unique, reflective wave that contains the encoded desired, local variable measurement. This reflective wave emanates from the local antenna and is received back by the interrogator. The interrogator identifies which SAW sensor generated the signal and decodes the measurement.

Optionally, the monitoring apparatus includes a SAW antenna.

Optionally, the monitoring apparatus provides qualification testing during manufacture of the buoyancy module.

Optionally, the monitoring apparatus can be remotely activated. Optionally, the monitoring apparatus can be remotely activated by an acoustic wave.

In another aspect, the present invention provides a method of monitoring a condition or parameter of as subsea pipeline buoyancy module, comprising the step of operating a monitoring apparatus as defined herein and being part of the buoyancy module as also defined herein.

According to another aspect, the present invention relates to a monitoring apparatus as defined herein for monitoring a condition or parameter of a subsea pipeline buoyancy module as defined herein.

According to another embodiment of the present invention, the monitoring apparatus as defined herein, being in or on a subsea pipeline buoyancy module as defined herein, is for monitoring a condition or parameter of the subsea pipeline.

Generally, the present invention provides options to the skilled man to efficiently monitor a parameter or condition of a buoyancy module that can be installed on a flexible pipe, an umbilical or a rigid pipeline, and which can be retro-fitted to a buoyancy module as well as formed with, in or on the buoyancy module, partly or fully.

One simply way of monitoring a buoyancy module is to record its depth against time. Variation in depth could be measured by a pressure sensor that could take a measurement every regular period, such as every day, as pressure variations are expected to be slow and a long term trend is of more interest.

The present invention is able to work at any monitoring speed, whether it is in a short period, such as slamming load, or over time such as slow pressure variations in use. The ability to have low power sensing and monitoring devices and units means that the monitoring apparatus can be located on, in or otherwise attached to the buoyancy module itself, optionally as part of the manufacturing and/or curing of the buoyancy module manufacturing process. Temperature monitoring during curing of the material forming the buoyancy module, such as syntactic foam, could be used to determine correct curing of the material.

The low power required by the monitoring apparatus allows the use of simple battery technology, and/or simple power generation units known in the art and able to achieve low current, optionally intermittent power supply.

In one embodiment of the present invention, the buoyancy module could be inspected and/or interrogated daily or weekly or similar, and include one or more memory or data stores, which could be removed or interrogated either remotely or directly by a subsea diver or ROV. As buoyancy modules are typically large items, location of a higher powered or higher current battery is achievable if required, and recharge of a suitable battery by induction is also possible using the known power generation techniques.

Optionally, the buoyancy module is formed with one or more locations, apertures or spaces for the supply of one or more operating apparatus’, for monitoring either directly or regularly, optionally via an aperture coverable with a suitable cap to ensure that marine growth is not effecting the docking mechanism. Interrogating the monitoring apparatus shortly after installation should not be an additional cost to the user, as typically a configuration survey is performed where the subsea diver or ROV will come in close contact with the buoyancy modules anyway.

Where the buoyancy module of the present invention includes a data recording mechanism, optionally this is retrievable.

One embodiment of the present invention may be to measure the growth of marine life on the buoyancy module over time, such as using one or several time lapsed low light cameras, for example a camera with an integral LED light ring, installed on the side of the buoyancy module. Such cameras could over the years record the change, including the appearance in growth of marine life, which would also allow oil companies and research institutions to consider marine growth models and optimise inspection/cleaning campaigns.

The monitoring apparatus of the present invention could also be standardised in the way such that it could be installed either during installation or retro-fitted, to a variety of buoyancy modules. The buoyancy module monitoring apparatus could even include an acoustic modem or be adapted to release itself and float to the surface after a defined period of time, to be picked up and interrogate thereafter.

Where the pipeline includes one or more fibre optic cables, it may be possible to divert or include a branch line from the fibre optic cable to allow connection to a sensor or other monitoring apparatus on the buoyancy module, which may further allow real time and/or constant detailed monitoring of a condition or parameter along the fibre optic cable, including marine growth, especially where the use of several fibre optic cables or similar could allow monitoring completely around a buoyancy module.

For interrogation of a monitoring apparatus, one or more apertures in the buoyancy module have been described herein to allow an interrogatory unit to achieve close proximity to a sensor or a sensor array monitoring a condition or parameter, alternatively the SAW antenna could be integrated in the surface of the module to allow its interrogation when the interrogating antenna comes close to it. In a further alternative, a combination of interrogator and interrogation units could be used to link the monitoring apparatus with a suitable subsea acoustic modem.

Most generally, the present invention is able to integrate monitoring apparatus with a buoyancy module, to monitor a condition or parameter of the buoyancy module in a way not possible in the prior art. This includes monitoring parameters such as depth, the buoyancy module motion, slamming load in the splash zone, seawater properties, and marine growth progression on the buoyancy module. In this way, the sensors used for monitoring a condition or parameter of the buoyancy module can include one or more of the group selected from; common pressure, motion, temperature, acoustic and optical sensors including more specific sensors mentioned herein such as Surface Acoustic Wave sensors, fibre optic cables or sensors etc.

In particular, the present invention provides a way such that the monitoring apparatus can be self-powered or self-energised, although otherwise include one or more dedicated batteries.

In the present invention, the location of the sensors can be directly on the external surface of the buoyancy module, or embedded within the buoyancy module surface, structure or other part, such as on or within the clamp or clamping means to secure the buoyancy module to a pipeline. The present invention includes the location of one or more sensors, as well as the monitoring apparatus, as part of the manufacturing of the buoyancy module. Alternatively, one or more of the sensors and/or monitoring apparatus can be installed on the buoyancy module after the manufacturing phase, or even retro-fitted to existing buoyancy modules.

Applying the present invention to the manufacturing phase of a buoyancy module allows sensors to monitor the manufacturing conditions of the buoyancy module, such as the foam injection temperature parameter. In this way, a critical determination of the integrity of a buoyancy module even before its use in the sea can be determined.

The present invention can be self-powered, such as by the induction effect, or powered through an electrical power generated by a specific source or generator, such as a mini-hydro turbine, or the Seebeck effect as described herein.

The present invention allows the combination of any of features, embodiments or aspects discussed, and the skilled man can see the requirements to make such combination. It is clear that the present invention is able to monitor more than one parameter or condition either at the same time, or over the same or an overlapping time period, and/or at different frequencies of time, and/or different directions, actively/ passively, etc.

By way of example only, the monitoring apparatus could actively monitor a pressure parameter, such as depth, whilst also monitoring a strap tension. Optionally, the monitoring device includes a central processing unit, recording means or similar, able to record and store values or more than one type of measurement at the same time.

In an embodiment of the present invention discussed herein, a power supply to the buoyancy module could be extended from a power line in the associated pipeline at or near the buoyancy module by an extension or branch thereof. In a similar manner, one or more transmission cables, able to transmit or otherwise transfer monitored data to or from a buoyancy module, could be extended from the associated pipeline at or near the buoyancy module by an extension or branch thereof. One or more of any such transmission cables could be optical fibres. Such an arrangement could allow more detailed and/or continuous monitoring of the buoyancy module, optionally without any restriction of the service life of a monitor or sensor, and with a larger possible data bandwidth.

This may particularly suit where the pipeline is a riser, and the pre-determined location of any buoyancy module intended to be connected thereto is well defined in advance, so that the pipeline can be adapted during manufacture to match the buoyancy module requirements. The or each line or cable could be coupled or connected during installation, and be designed to monitor a buoyancy module at a predetermined location along the flexible pipe length. Indeed, the pipeline itself could be designed to includes one or more dedicated buoyancy module power lines and/or transmission cables.

Such as arrangement could also allow monitoring of the pipeline location or port providing any such power lines and/or transmission cables from a pipeline. For example, the provision of one or more such power lines and transmission cables from a pipeline may result in flooding of a section or part of its annulus, and any such pipeline annulus condition could also be monitored as part of the present invention.

In this disclosure, whenever a composition, an element or a group of elements is preceded with the transitional phrase comprising, it is understood that we also contemplate the same composition, element or group of elements with transitional phrases consisting essentially of”, consisting, selected from the group of consisting of”, “including”, or is preceding the recitation of the composition, element or group of elements and vice versa. In this disclosure, the words “typically” or “optionally” are to be understood as being intended to indicate optional or nonessential features of the invention which are present in certain examples but which can be omitted in others without departing from the scope of the invention.

References to directional and positional descriptions such as inner and outer, and directions e.g. “up”, “down” etc. are to be interpreted by a skilled reader in the context of the examples described to refer to the orientation of features shown in the drawings, and are not to be interpreted as limiting the invention to the literal interpretation of the term, but instead should be as understood by the skilled addressee.

Referring to figure 1, there is shown a subsea pipeline buoyancy module 2 comprising a monitoring apparatus 4 to monitor a condition or parameter of the buoyancy module 2.

The monitoring apparatus 4 is shown being integral with the buoyancy module 2, and indeed sitting alongside a central general aperture 6 of the buoyancy module 2 being a general cylindrical shape. Optionally, an aperture is formed in the buoyancy module 2 during manufacture to house the monitoring apparatus 4.

Figure 1 also shows a pod hole 8 extending from the monitoring apparatus 4 to an outer surface 10 of the buoyancy module 2. The pod hole 8 has a funnel entry 12, which can be sealed using a suitable plug 14. The plug 14 can prevent marine growth etc. from interfering with the monitoring apparatus 4. The pod hole 8 is accessible by a Remotely Operated Vehicle (ROV) 16 or a subsea diver (see figure 2).

The monitoring apparatus 4 also comprises two sensors 20, having fibre optic cables 22 extending between the monitoring apparatus 4 and the head of each sensor 20, which can also be on or near the outer surface 10 of the buoyancy module 2. Each sensor head 20 can monitor a condition or parameter of the buoyancy module 2, optionally in real in time or optionally periodically. Such conditions or parameters include depth, temperature, salinity, foam curing, slamming load, motion, pressure, acoustics, visual or optical view, stress, strain, tension, or the like. Optionally, the monitoring apparatus 4 includes an integral data storage means (not shown), or a separable data storage means (not shown).

Figure 1 shows a ROV 16 approaching the buoyancy module 2 in order to inspect or interrogate the monitoring apparatus 4, in particular to access data in any data storage means, optionally to separate the data storage means from the remainder of the monitoring apparatus 4, and optionally to replace it with a further data storage means for subsequent monitoring. The ROV 16 may comprise one or more arms, handles, or other manipulating means known in the art, able to open the plug 14, and access the monitoring means 4 via the pod hole 8.

Figure 1 also shows the monitoring means 4 being powered by a power source 26, located in a separate location in the buoyancy module 2, optionally in a defined aperture created in the buoyancy module 2 therefor, and connected to the monitoring apparatus 4 via a power transmission line 28. Optionally, the power source 26 is one or more batteries, including water-activated batteries, induction rechargeable batteries and certain known dedicated batteries including those being LiSi-CoS2 batteries.

The buoyancy module 2 shown in figure 1 is intended to surround a pipeline (not shown) via the central aperture 6.

The sensors 20 could be thermocouples to measure a sea temperature, camera lens or eyes or the like, to view the buoyancy module.

In one embodiment of the present invention, the sensors 20 and their leads 22 comprise part of a Surface Acoustic Wave (SAW) sensor array, and the monitoring apparatus includes SAW antenna (not shown) which an be used to help interrogate the monitoring apparatus 4 for the SAW data.

Figure 2 shows a second subsea pipeline buoyancy module 30 according to another embodiment of the present invention, located on a pipeline 32, and approached by a subsea diver 34. The second buoyancy module 30 has a cylindrical outer shape, and a central aperture being funnelled from each end, towards a central clamp or clasp 36 able to secure the buoyancy module 30 to the pipeline 32 in use. The subsea diver 34 can approach the buoyancy module 30 to inspect or interrogate the monitoring apparatus 38. The subsea diver 34 could remotely interrogate the monitoring apparatus 38, optionally using acoustic waves or the like.

The monitoring apparatus 34 can monitor the status of the clamp 36, in particular either the tension of the clamp 36, in particular any straps or the like extending around the pipeline 32, and optionally stress and/or strain of the clamp where it is formed from a material such as an elastomer, such as rubber, having one or more steel or other metal inserts, in particular certain metallic elements, whose stress and strain can be measured using suitable fibre optic cables inserted through the clamp 36 during its manufacture.

In this way, the subsea diver 34 can use the monitoring apparatus 38 to determine the integrity of the clamp 36 prior to or during use of the buoyancy module on the pipeline 32, in particular for a regular service check or update of the buoyancy module integrity. The subsea diver 34 can interrogate the monitoring apparatus 36 for the recordal of any stress/strain and/or temperature in the rubber data, potentially at several locations through the surface or cross section of the clamp 36.

Figure 3 shows one half of a third subsea pipeline buoyancy module 40, being another embodiment of the present invention. The half shell 40 shows a suitable internal location for a monitoring apparatus 42, and an associated power source 44. The monitoring apparatus 42 and the power source 44 can be located within the half shell 40 during its manufacture, along with an embedded handle 45 having a portion extending beyond the outer surface 46 of the half shell 40, and able to be used as a fixing or attachment point for an interrogator such as an ROV or subsea diver, when working at or near the buoyancy module 40, in particular when seeking to interrogate the monitoring apparatus 42.

Figure 4 shows the use of the half shell 40 shown in figure 3, along with a complimentary other half shell 50, formed around a pipeline 52, and fastened thereto using two straps 54 in a manner known in the art, to secure the half shells 40, 50 to the pipeline 52. Figure 4 also shows two sensors 56 extending to the clamps 54, in order to monitor a condition or parameter of the straps 54, which condition or parameter is an indictor of the integrity of the clamps and the integrity of their function of maintaining the buoyancy module collective formed by the half shells 40, 50 around the pipeline 52. Figure 4 also shows an aperture 58 to allow an interrogator to access an internal monitoring apparatus (not shown), in a manner similar to that described herein above.

Figure 5 shows a fourth subsea pipeline buoyancy module 60 as another embodiment of the present invention, generally having a cylindrical outer shape and a central aperture 62 for the location of a pipeline (not shown).

Figure 5 shows various alternative or combinations of power generation units able to provide power to a monitoring apparatus (not shown) in the fourth buoyancy module 60.

One power generation unit comprises an external propeller 64 able to be turned by motion of the environment or sea surrounding the buoyancy module 60, which mechanical motion can then be translated into electrical power using a suitable generator or generating unit known in the art.

Figure 5 also shows two fins 66 extending transversely from the outer surface of the buoyancy module 60, which fins can be mechanically moved, in particular rotated and/or translated in relation to a suitable pivot point with this outer surface of the buoyancy module 60. Again, the mechanical movement of the fin 66 can be translated into electrical power.

Figure 5 also shows and internal through hole 68 extending longitudinally within the buoyancy module 60, and having a mini-hydro turbine 70 located therein. The through hole 68 uses the flow of water to create movement of a turbine to generate power.

Figures 1-5 show various power supply or power sourcing apparatus and arrangements, so that the buoyancy module could also act as a ‘charging station’ for any apparatus or equipment docking therewith. For example, the pod hole 8 in Figure 1 can be a ‘docking station’ for an ROV 16, and connecting the ROV 16 with the buoyancy module via the pod hole 8 could allow re-charging of the ROV power supply, typically batteries, whilst it is also monitoring or interrogating various sensors (20, 56)..

Figure 6 shows a subsea pipeline 70 between a surface vessel 72 and a unit 73 on a seabed 74, having three subsea pipeline buoyancy modules 76 located there. The middle subsea pipeline buoyancy module 78 at least comprises monitoring apparatus as described herein to monitor a condition or parameter of the buoyancy module, such as depth over time. In this way, the positional depth of the subsea pipeline buoyancy module 78 and therefore the pipeline can be determined, to ensure the correct desired position of the pipeline 70. Incorrect or undesired positional depth measurements could illustrate a damaged buoyancy module or other problem to be fixed prior to any catastrophic event or failure of the pipeline 70.

Whilst every buoyancy module along a pipeline could have or include a monitoring apparatus, it is expected that a pipeline has a combination of conventional buoyancy modules and one or more monitoring buoyancy modules.

Figure 7 shows a simple battery cell 80 based in using seawater as the electrolyte 82 between a suitable anode 84 and cathode 86, optionally sized to last for the service lifetime of a buoyancy module. The cell 80 could be a power source for a monitoring apparatus as described herein.

Claims

1. A subsea pipeline buoyancy module comprising monitoring apparatus to monitor a condition or parameter of the buoyancy module.

2. A subsea pipeline buoyancy module as claimed in claim 1 wherein the monitoring apparatus is integral with the buoyancy module.

3. A subsea pipeline buoyancy module as claimed in claim 1 wherein the monitoring apparatus is attachable to the buoyancy module.

4. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus is accessible by a subsea diver or a Remotely Operated Vehicle (ROV).

5. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein one or more apertures are formed in the buoyancy module to house the monitoring apparatus.

6. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein one or more apertures are formed in the buoyancy module to access the monitoring apparatus.

7. A subsea pipeline buoyancy module as claimed in claim 6 wherein one aperture is a pod hole.

8. A subsea pipeline buoyancy module as claimed in claim 6 or claim 7 wherein one aperture has a funnel entry.

9. A subsea pipeline buoyancy module as claimed in any one of claim 6-8 wherein one aperture can be sealed.

10. A subsea pipeline buoyancy module as claimed in any one of claim 6-9 wherein one aperture is accessible by a ROV or a subsea diver.

11. A subsea pipeline buoyancy module as claimed in any one of the preceding claims further comprising a power supply.

12. A subsea pipeline buoyancy module as claimed in claim 11 wherein the power supply is provided along the subsea pipeline or from within the subsea pipeline.

13. A subsea pipeline buoyancy module as claimed in claim 11 wherein the power supply is provided on the buoyancy module.

14. A subsea pipeline buoyancy module as claimed in claim 11 wherein the power supply is provided in the buoyancy module.

15. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring device is powered by one or more of the group comprising; a water-activated battery, an induction rechargeable battery, and a LiSi/CoS2 battery.

16. A subsea pipeline buoyancy module as claimed in any one of the preceding claims comprising one or more of the group comprising: a module motion power generation unit, a subsea temperature differential power generation unit, a flexible fin power generation unit and a hydro turbine power generation unit.

17. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus monitors a condition or parameter of the buoyancy module on land, during installation, during subsea testing, and/or during subsea use.

18. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus actively monitors a subsea condition or parameter of the buoyancy module.

19. A subsea pipeline buoyancy module as claimed in any one of claims 1-17 wherein the monitoring apparatus passively monitors a condition or parameter of the buoyancy module.

20. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus monitors a condition or parameter of the buoyancy module in real time.

21. A subsea pipeline buoyancy module as claimed in any one of claims 1 to 20 wherein the monitoring apparatus periodically monitors a condition or parameter of the buoyancy module.

22. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus monitors one or more of the group comprising: depth, temperature, salinity, foam curing, slamming load, motion, pressure, acoustics, opticals, visuals, stress, strain and tension.

23. A subsea pipeline buoyancy module as claimed in claim 22 wherein the monitoring apparatus periodically monitors depth of the buoyancy module over time.

24. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus includes an integral data storage means.

25. A subsea pipeline buoyancy module as claimed in any one of claims 1-23 wherein the buoyancy module has a separable data storage means.

26. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the pipeline is a flexible pipeline, an umbilical or a rigid pipeline.

27. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the buoyancy module comprises two half shells and a clamp.

28. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the buoyancy module includes a clamp to clamp the buoyancy module onto the subsea pipeline, and the monitoring apparatus monitors a condition or parameter of the clamp.

29 A subsea pipeline buoyancy module as claimed in claim 28 wherein the clamp comprises one or more elastomeric elements having one or more metallic inserts.

30. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the buoyancy module has a flat outer surface portion to mount the monitoring apparatus.

31. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus is locked to the buoyancy module.

32. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus is a self sufficient and replaceable unit.

33. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus includes an attitude sensor

34. A subsea pipeline buoyancy module as claimed in any one of the preceding claims having a monitoring unit for monitoring slamming load during launch of the buoyancy module into the sea from a vessel.

35. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus comprising a sensor, a linking cable, and a gathering unit.

36. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus comprising one or more thermocouples and/or optical fibre cables.

37. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus is a monitoring module.

38. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus comprising a time-lapse camera

39. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus is floatable and self-releasable from the buoyancy module.

40. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus comprises a Surface Acoustic Wave (SAW) sensor array.

41. A subsea pipeline buoyancy module as claimed in claim 40 wherein the monitoring apparatus includes a SWA antenna.

42. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus provide monitoring information during the qualification testing or during the manufacturing process of the buoyancy module.

43. A subsea pipeline buoyancy module as claimed in any one of the preceding claims wherein the monitoring apparatus can be remotely activated.

44. A subsea pipeline buoyancy module as claimed in claim 43 wherein the monitoring apparatus can be remotely activated by acoustic waves

45. A method of monitoring a condition or parameter of a subsea pipeline buoyancy module comprising the step of operating a monitoring apparatus as defined in any one of claims 1-44 being part of the buoyancy module as defined in any one of claims 1-44.

46. A monitoring apparatus as defined in any one of claims 1-44 for monitoring a condition or parameter of a subsea pipeline buoyancy module as defined in any one of claims 1-44.

47. A monitoring apparatus as defined in any one of claims 1-44 on or in a subsea pipeline buoyancy module as defined in any one of claims 1-44 for monitoring a condition or parameter of the subsea pipeline.

Intellectual

Property

Office

Application No: GB1705433.9 Examiner: James Paddock