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Title:
SUBSEA MONITORING APPARATUS
Document Type and Number:
WIPO Patent Application WO/2022/157485
Kind Code:
A1
Abstract:
There is provided a subsea instrumentation unit (20) comprising a housing having an internal volume and a control system located within the internal volume. The control system comprises a controller, a memory in communication with the controller, a power supply, and a transmitter and receiver adapted to transmit and receive data. The instrumentation unit further comprises at least one environmental sensor adapted to sense environmental conditions in the vicinity of the unit (20) and communicate environmental data to the controller and/or memory. Also provided are a subsea foundation (2) and a subsea monitoring apparatus comprising a subsea foundation and a subsea instrumentation unit (20) selectively attached to the foundation by mechanical fixings.

Inventors:
WILSON ROSS (GB)
Application Number:
PCT/GB2022/050129
Publication Date:
July 28, 2022
Filing Date:
January 18, 2022
Export Citation:
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Assignee:
REAMAN ENGINEERING LTD (GB)
International Classes:
B63B22/20; B63B21/29; G01C13/00
Attorney, Agent or Firm:
MURGITROYD & COMPANY (GB)
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Claims:
CLAIMS:

1. A subsea instrumentation unit comprising: a housing having an internal volume; a control system located within the internal volume and comprising: a controller; a memory in communication with the controller; a power supply; and a transmitter and receiver adapted to transmit and receive data; and at least one environmental sensor adapted to sense environmental conditions in the vicinity of the unit and communicate environmental data to the controller and/or memory.

2. The subsea instrumentation unit of claim 1 , wherein the power supply comprises a generator powered by tidal flow or current.

3. The subsea instrumentation unit of claim 2, wherein the power supply comprises one or more rechargeable batteries which are charged by the generator.

4. The subsea instrumentation unit of any preceding claim, wherein the one or more environmental sensors is selected from the group comprising a water speed sensor, a water direction sensor, and an external heat sensor.

5. The subsea instrumentation unit of any preceding claim, wherein the control system further comprises an internal heat sensor located in the internal volume and in communication with the controller.

6. The subsea instrumentation unit of any preceding claim, further comprising an external camera adapted to relay pictures to the controller.

7. The subsea instrumentation unit of any preceding claim, further comprising a compass in communication with the controller;

8. The subsea instrumentation unit of any preceding claim, further comprising a distance measuring device adapted to measure the distance between the unit and a subsea asset in the vicinity of the unit.

9. The subsea instrumentation unit of claim 8, wherein the distance measuring device uses sonar or LIDAR to measure the distance.

10. The subsea instrumentation unit of any preceding claim, further comprising a height measuring device adapted to measure the height between the unit and surface waves above the unit.

11. The subsea instrumentation unit of claim 10, wherein the height measuring device uses sonar or LIDAR to measure the height.

12. The subsea instrumentation unit of any preceding claim, further comprising a locator beacon.

13. The subsea instrumentation unit of any preceding claim, further comprising an elastomeric skirt which extends around the circumference of an underside of the housing.

14. The subsea instrumentation unit of any preceding claim, wherein one or more walls of the housing is adapted to transfer heat from the internal volume to the exterior of the unit.

15. The subsea instrumentation unit of any preceding claim, further comprising a winch attached to the housing, the winch carrying a tether line having a first end attached to the winch and a second end attachable to a surface buoy for retrieval of the unit to the surface.

16. A subsea monitoring apparatus comprising: a subsea foundation; and a subsea instrumentation unit according to any preceding claim; wherein the instrumentation unit is selectively attached to the foundation by a plurality of mechanical fixings. The subsea monitoring apparatus of claim 16, wherein the foundation is formed from concrete containing metal reinforcing members, wherein the mechanical fixings are attachable to the reinforcing members. The subsea monitoring apparatus of claim 16 or claim 17, wherein the foundation includes a ballast chamber adapted to receive ballast in order that the weight of the foundation can be varied. The subsea monitoring apparatus of claim 18, wherein the ballast chamber is covered by an access panel. The subsea monitoring apparatus of claim 18 or claim 19, wherein the foundation further comprises ballast adapted to be received in the chamber, and wherein the chamber comprises a plurality of recesses and the ballast comprises metal bars adapted to be fixed within the recesses. The subsea monitoring apparatus of any of claims 16 to 20, wherein the foundation is circular and has a lower foundation portion having a larger diameter than an upper foundation portion. The subsea monitoring apparatus of claim 21, wherein a retrieval member is attached to the foundation, the member including one or more attachment points connectable to a retrieval means. The subsea monitoring apparatus of claim 22, wherein the retrieval member is a metal ring which surrounds the upper foundation portion. The subsea monitoring apparatus of any of claims 16 to 23, wherein the foundation further comprises spikes adapted to anchor the foundation to the seabed. The subsea monitoring apparatus of claim 24, wherein the spikes are integrally formed with the foundation.

26. A subsea foundation comprising: a support surface adapted to receive a subsea asset, the support surface having a plurality of attachment apertures for attaching the asset to the foundation; and a ballast chamber adapted to receive ballast in order that the weight of the foundation can be varied.

27. The subsea foundation of claim 26, wherein the ballast chamber is covered by an access panel.

28. The subsea foundation of claim 26 or claim 27, wherein the foundation further comprises ballast adapted to be received in the chamber, and wherein the chamber comprises a plurality of recesses and the ballast comprises metal bars adapted to be fixed within the recesses.

29. The subsea foundation of any of claims 26 to 28, wherein the foundation is circular and has a lower foundation portion having a larger diameter than an upper foundation portion.

30. The subsea foundation of claim 29, wherein a retrieval member is attached to the foundation, the member including one or more attachment points connectable to a retrieval means.

31. The subsea foundation of claim 30, wherein the retrieval member is a metal ring which surrounds the upper foundation portion.

32. The subsea foundation of any of claims 26 to 31, wherein the foundation further comprises spikes adapted to anchor the foundation to the seabed.

33. The subsea foundation of claim 32, wherein the spikes are integrally formed with the foundation.

34. A method of monitoring environmental conditions and events at a subsea location, the method comprising: removably attaching a subsea instrumentation unit to a subsea foundation to form a subsea monitoring apparatus, the instrumentation unit comprising at least one environmental sensor; activating the instrumentation unit so as to record data from the at least one environmental sensor; deploying the subsea apparatus at the subsea location; and selectively transmitting the recorded data to a remote location.

35. The method of claim 34, wherein the subsea foundation is a subsea foundation according to any of claims 26 to 33.

36. The method of claim 34 or claim 35, wherein the instrumentation unit is an instrumentation unit according to any of claims 1 to 15. 37. The method of any of claims 34 to 36, wherein the remote location is a support vessel, and the selective transmission occurs when the vessel comes within a predetermined distance of the instrumentation unit.

Description:
SUBSEA MONITORING APPARATUS

Field of the Invention

The present invention relates to the monitoring and investigation of offshore environments and assets. More specifically, the present invention is a subsea monitoring apparatus for monitoring subsea environments in which subsea assets such as power cables are located.

Background of the Invention

Offshore power generation continues to grow in importance, whether that be wind, tidal or wave power. During the planning and subsequent operation of offshore power installations it is important to obtain reliable environmental data from the location of the offshore installation and related service lines, but this can be a challenge. Due to demand, an ever increasing number of installations and service lines are being installed by inexperienced parties. This has had a detrimental impact on, or even caused the failure of, Cable Protection Systems (CPS) and/or foundations in recent years.

There is therefore a need to accurately investigate and monitor subsea environments where such offshore installations are planned or already located. Apparatus presently used in the investigation and monitoring of subsea assets has a number of disadvantages. For example, one conventional means of establishing meteorological data at an offshore location is to employ a fixed meteorological tower or mast. These fixed installations, commonly known as “met masts”, are mounted upon a foundation laid upon the seabed and extend upwards such that the monitoring equipment carried on the tower/mast is located above the surface of the water. The main disadvantages of such met masts is that they are extremely expensive to build and install, and are also vulnerable to damage should anything inadvertently run into the mast.

A lower cost alternative to met masts is to house the required monitoring instruments in a “wave rider” buoy. These buoys are deployed on the surface of the water and held in position by one or more subsea anchors. Their lower cost allows multiple monitoring buoys to be deployed in an area for the same cost as one met mast. However, these buoys are even more vulnerable to damage from passing vessels due to their low profile in the water. Indeed, there have also been allegations that such buoys are deliberately targeting by passing sea traffic.

As regards inspection of subsea assets the conventional procedure is to employ a Remote Operating Vehicle (ROV), which is sent down to inspect the asset. Again, the cost of these ROV inspections is significant and they are therefore only carried out on an irregular basis due to budgetary constraints.

It is an aim of the present invention to obviate or mitigate one or more of the aforementioned disadvantages.

Summary of the Invention

According to a first aspect of the invention there is provided a subsea instrumentation unit comprising: a housing having an internal volume; a control system located within the internal volume and comprising: a controller; a memory in communication with the controller; a power supply; and a transmitter and receiver adapted to transmit and receive data; and at least one environmental sensor adapted to sense environmental conditions in the vicinity of the unit and communicate environmental data to the controller and/or memory.

The power supply may comprise a generator powered by tidal flow or current. The power supply may comprise one or more rechargeable batteries which are charged by the generator.

The one or more environmental sensors may be selected from the group comprising a water speed sensor, a water direction sensor, and an external heat sensor.

The control system may further comprise an internal heat sensor located in the internal volume and in communication with the controller. The unit may further comprise an external camera adapted to relay pictures to the controller.

The unit may further comprise a compass in communication with the controller;

The unit may further comprise a distance measuring device adapted to measure the distance between the unit and a subsea asset in the vicinity of the unit. The distance measuring device may use sonar or LIDAR to measure the distance.

The unit may further comprise a height measuring device adapted to measure the height between the unit and surface waves above the unit. The height measuring device may use sonar or LIDAR to measure the height.

The unit may further comprise a locator beacon.

The unit may further comprise an elastomeric skirt which extends around the circumference of an underside of the housing.

One or more walls of the housing may be adapted to transfer heat from the internal volume to the exterior of the unit.

The unit may further comprise a winch attached to the housing, the winch carrying a tether line having a first end attached to the winch and a second end attachable to a surface buoy for retrieval of the unit to the surface.

According to a second aspect of the invention there is provided a subsea monitoring apparatus comprising: a subsea foundation; and a subsea instrumentation unit according to the first aspect of the invention; wherein the instrumentation unit is selectively attached to the foundation by a plurality of mechanical fixings.

The foundation may be formed from concrete containing metal reinforcing members, wherein the mechanical fixings are attachable to the reinforcing members. The foundation may include a ballast chamber adapted to receive ballast in order that the weight of the foundation can be varied. The ballast chamber may be covered by an access panel. The foundation may further comprise ballast adapted to be received in the chamber, wherein the chamber comprises a plurality of recesses and the ballast comprises metal bars adapted to be fixed within the recesses.

The foundation may be circular and have a lower portion having a larger diameter than an upper portion. A retrieval member may be attached to the foundation, the member including one or more attachment points connectable to a retrieval means. The retrieval member may be a metal ring which surrounds the upper foundation portion.

The foundation may further comprise spikes adapted to anchor the foundation to the seabed. The spikes may be integrally formed with the foundation.

According to a third aspect of the invention there is provided a subsea foundation comprising: a support surface adapted to receive a subsea asset, the support surface having a plurality of attachment apertures for attaching the asset to the foundation; and a ballast chamber adapted to receive ballast in order that the weight of the foundation can be varied.

The chamber may be covered by an access panel. The foundation may further comprise ballast adapted to be received in the chamber, wherein the chamber comprises a plurality of recesses and the ballast comprises ballast bars adapted to be fixed within the recesses.

The foundation may be formed from concrete containing metal reinforcing members, wherein an end of a reinforcing member is located at the bottom of each attachment aperture.

The foundation may be circular and have a lower portion having a larger diameter than an upper portion. A retrieval member may be attached to the foundation, the member including one or more attachment points connectable to a retrieval means. The retrieval member may be a metal ring which surrounds the upper foundation portion.

The foundation may further comprise spikes adapted to anchor the foundation to the seabed. The spikes may be integrally formed with the foundation.

According to a fourth aspect of the present invention there is provided a method of monitoring environmental conditions and events at a subsea location, the method comprising: removably attaching a subsea instrumentation unit to the subsea foundation to form a subsea monitoring apparatus, the instrumentation unit comprising at least one environmental sensor; activating the instrumentation unit so as to record data from the at least one environmental sensor; deploying the subsea apparatus at the subsea location; and selectively transmitting the recorded data to a remote location.

The subsea foundation may be a subsea foundation in accordance with the third aspect of the invention.

The instrumentation unit may be an instrumentation unit in accordance with the first aspect of the invention.

The remote location may be a support vessel, and the selective transmission occurs when the vessel comes within a predetermined distance of the instrumentation unit.

Brief Description of the Drawings

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the following drawings:

Figure 1 is a top view of a subsea foundation of a subsea monitoring apparatus;

Figure 2 is a bottom view of the foundation of figure 1 ;

Figure 3 is a top view of an instrumentation unit of the subsea monitoring apparatus; Figure 4 is a vertical section through the instrumentation unit of figure 3 along the line IV-IV;

Figure 5(a) is a horizontal section through the instrumentation unit of figures 3 and 4;

Figure 5(b) is a vertical section through the instrumentation unit of figure 5(a) along the line 5(b)-5(b); and

Figure 6 shows the subsea monitoring apparatus in use.

Detailed Description of the Drawings

Figures 1 and 2 show views of a base unit or foundation 2 which forms part of a subsea monitoring apparatus. As shown in figure 1 , the foundation 2 is substantially circular and is comprised of a lower foundation portion 4 and an upper foundation portion 6, which are preferably integrally formed. The upper and lower foundation portions 4,6 are preferably formed from reinforced concrete, with metal reinforcing members extending substantially vertically through the foundation 2.

The lower foundation portion 4 has a larger diameter than the upper foundation portion 6, such that a step is formed where the two portions meet. The upper foundation portion 6 may be encircled by a steel ring 8, which sits upon the lower foundation portion 4. The steel ring 8 may be a single piece, or alternatively it may be formed from a plurality of segments attached to one another to form a ring. The steel ring 8 may be attached to the lower foundation portion 4 by steel rods which pass through or into the lower foundation portion. The ring 8 has one or more attachment points (not shown) and acts as a retrieval member, where a retrieval means (e.g. a surface-based winch and tether) can be attached to allow retrieval of the foundation.

Attachment apertures 10 are provided in the upper surface 7 of the upper foundation portion 6. The apertures 10 may be positioned so that an end of a reinforcing member in the concrete is located at the bottom of each aperture. These apertures 10 will be used to attach an instrumentation unit to the foundation 2, as will be described in more detail below.

The foundation may be sized according to its intended environment and/or application, but in this preferred embodiment the lower foundation portion 4 is 3m in diameter and the upper foundation portion is 1m in diameter. The steel ring 8 has an outer diameter of 2.5m and an inner diameter of 1m. Each of the foundation portions 4,6 and ring 8 are preferably 300mm in height, giving the foundation 2 a total preferred height of 600mm.

Spikes may be formed on the underside of the foundation to allow the foundation to anchor to, or grip, the seabed. These spikes may be formed from metal embedded in, or attached to, the concrete foundation or alternatively may be cast as part of the concrete foundation itself. Holes or passages may be formed in the foundation, which allow water to enter and reduce the mass of the foundation.

Figure 2 shows the underside of the foundation 2, and the lower foundation portion 4 specifically in this embodiment. An access panel (not shown) can be secured in a ballast chamber 12 in the underside and has been removed in figure 2 for illustrative purposes. Recesses in the preferred form of slots 14 are formed in the chamber 12 and the slots and chamber are usually hidden behind the access panel. Each slot 14 has a number of bolt holes (not shown) which allow ballast in the form of metal or plastic ballast bars 16 to be fitted in the slots 14 by bolts 18 or similar mechanical fixtures. This ballast allows the weight, and hence the stability, of the foundation to be adjusted. The access panel has a single or double seal to prevent water from entering the chamber 12.

In the illustrated embodiment the access panel and chamber 12 are 1.5m by 1.2m. The slots and bars are 1m long, 0.1m thick and 0.1m wide, and there are seven slots/bars in the chamber 12. The dimensions of the chamber 12 and the number of recesses and associated ballast therein can be varied according to environmental and application requirements.

Figure 3 is a top view looking downwards into the interior of an instrumentation unit 20 of the subsea monitoring apparatus. Bolt holes 22 are provided in the unit 20 which match with the apertures 10 in the foundation, allowing the unit 20 to be selectively attached to the foundation by bolts or similar mechanical fixtures.

Figure 4 is a cross section through the unit 20 when it is empty. It can be seen that the unit 20 defines an internal chamber or volume 26. The unit is preferably formed from moulded polyurethane or a similar plastics material. A metal plate 27 is provided inside the bottom of the chamber 26. The chamber 26 is open at the top, and a lid 28 is secured to the top of the unit to enclose the chamber. The lid 28 is also preferably formed from polyurethane or a similar plastics material and may have a single or double seal in order to prevent the ingress of water into the chamber 26. A skirt 24 formed from neoprene or a similar elastomeric material extends around the circumference of the underside of the unit 20 so as to form a seal when the unit 20 is secured to the foundation 2, thereby preventing ingress of water between the unit 20 and the foundation 2 when they are attached to one another.

In the illustrated embodiment the unit 20 is preferably 1m in diameter, with the internal diameter of the chamber 26 preferably 0.95m. The chamber may be 0.55m in height, with the overall height of the unit preferably 0.6m.

Figures 5(a) and 5(b) are section views showing the chamber 26 and interior of the unit 20 when components of a control system are housed therein. The components may vary depending upon application, but in this illustrated embodiment there is provided a controller 30, a power management module 32 for controlling the charging and power supply to the controller 30, a rechargeable battery pack 34, and a generator 36, which is preferably driven by tide or current flow. The control system further comprises a memory and a transmitter/receiver.

One or more sensors are included in the control system, to communicate sensed data to the controller. The one or more sensors may be selected from the group comprising: a water speed sensor; a water direction sensor; one or more heat sensors, internal and/or external.

One or more accessories are included in the unit 20. The one or more accessories may be selected from the group comprising: a directional compass; an upwardly directed Light Detection and Ranging (LIDAR) wave height detector; a camera for continuous and/or still pictures; one or more camera lights; a distance detector (side sonar or LIDAR); a locator beacon; one or more locator lights. The accessories are controlled by the controller and aside from the beacon and lights can provide additional data to the controller, which can be stored. An outer wall of the unit 20 may include a heatsink plate 21 , whose outer face is in contact with the water and is adapted to transfer heat generated by the components inside the unit to the exterior of the unit. The heatsink plate 21 only forms a small part of the outer wall, and is preferably formed in place with the remainder of the outer wall during the moulding of the unit 20. The metal plate 27 in the base of the unit 20 acts as an earth for the components inside the unit.

Industrial Applicability

Figure 6 shows the subsea monitoring apparatus when in use. Firstly, the foundation 2 is prepared, including installing one or more ballast bars 16 in the base thereof if deemed necessary. The monitoring components are installed in the instrumentation unit 20 at an onshore location or else on the support vessel. The unit 20 is attached to the foundation using bolts or similar foundations via the apertures 10,22 in the foundation and unit. With the components installed and switched on, the unit 20 is then sealed via its lid 28.

The apparatus comprising the foundation 2 and unit 20 is then transported by support vessel and deployed on the seabed at a location to be monitored. This location may be adjacent to where subsea equipment 50 is, or will be, located.

Once installed on the seabed the control system will monitor and record environmental data at that location, with the controller in a data collection mode. When the recorded data is to be retrieved a support vessel 60 is sent to the location. The control system has a transmitter which is continuously emitting a locator signal. When the support vessel is not nearby the signal will go unanswered. However, when the vessel does come into the vicinity of the apparatus a corresponding transmitter/receiver on the vessel will send a reply signal back to the unit. This reply signal is received by the system, which switches to a data transmission mode and the stored data is transmitted to a corresponding system storage on the support vessel for later analysis. The support vessel will then move away from the vicinity of the apparatus and the control system will go back into a data collection mode until the next time the vessel is detected in the area. As well as a support vessel the data may be transmitted to another remote location, such as an on-shore site close to the location being monitored. The present invention provides a means of monitoring subsea environmental conditions over a wide area in a cost effective manner, without being vulnerable to damage from surface vessels. The present invention may also be used for intermittent or continuous monitoring and/or inspection of a subsea asset without the need to use expensive ROV equipment for the purpose. The present invention can also communicate its stored data whilst remaining in situ on the seabed.

The instrumentation unit may include an impeller unit adapted to provide power to the batteries through tidal streams or currents in the water.

Modifications and improvements may be incorporated without departing from the scope of the present invention.