GB2472801A

GB2472801A - Illuminating underwater objects with an ultraviolet light source

Info

Publication number: GB2472801A
Application number: GB0914431A
Authority: GB
Inventors: Cameron James Lawson
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-08-18
Filing date: 2009-08-18
Publication date: 2011-02-23
Also published as: GB201013818D0; GB2472915A; GB2472915B; GB0914431D0

Abstract

A method and apparatus for illuminating underwater objects 50 is disclosed, the method comprising: in an underwater environment, directing ultraviolet (UV) light 20 onto the underwater object 50 comprising UV reactive paint, such that the ultraviolet light interacts with the object to produce visible light. The invention may be used in low visibility underwater environments and the reflection of UV light from suspended particles 22 back to the operator does not result in glare because the UV light is invisible. When the UV light reaches the underwater object, such as a wellhead, it produces visible light. In this way the operator may more clearly see the underwater objects they are working with. Can be used on a remotely operated vehicle (ROV) 10 employing camera 16.

Description

Method and Apparatus This invention relates to a method and apparatus for illuminating underwater objects.

When conducting subsea activities it is necessary to light the objects or equipment being worked on to enable the diver or the operator of a remotely operated vehicle (ROV) to see what they are doing. This is normally achieved using high powered standard white light emitters mounted on the diver's helmet or on the ROy. Occasionally it may be handheld or standalone.

When the surrounding water is clear of particles then this works adequately.

However, this becomes unworkable when the surrounding environment has a significant number of suspended particles. The use of white light in this environment produces reflection (or back-scatter) of the light from the particles and so causes the eyes or the camera iris to contract thus producing large amounts of glare. Some of the light will still be penetrating the water and lighting the equipment but due to the immediate glare this cannot be seen.

One known method to tackle this problem is to use a combination of GPS, acoustic positioning devices and sonar. Although these devices, working in parallel, can get an ROV close to the equipment they cannot allow intervention on the equipment due to inaccuracy. Also, to intervene the ROV or diver must be able to see what they are doing as they may need to work on, for example, a single valve actuation. These devices cannot detect the smaller parts of a larger piece of equipment. The combined cost of these items is also significant.

According to a first aspect of the present invention, there is provided a method of illuminating underwater objects, the method comprising:

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in an underwater environment, directing ultraviolet light onto the underwater object, such that the ultraviolet light interacts with the object to produce visible light.

The use of uv light removes (or at least mitigates) the problems with visual glare to a human eye, whether directly or through a camera and monitor system.

Although the ultraviolet (uv) light will still be reflected by suspended particles, the resultant reflected light is beyond the human visual spectrum and as such is invisible.

A further advantage of the present invention is that the system can also be used in environments where there are little or no entrained particles in the water. The object will still be illuminated in the same manner and indeed potentially has more uv light reaching it.

"Underwater environment" typically means underwater, for example, subsea. In preferred embodiments the underwater environment is at least lOm deep (ie measured from the water surface), preferably at least 50m deep, and may be at least I OOm deep. For certain embodiments the depth may be more than 250m, optionally more than 500m and sometimes more than I,000m.

Preferably the underwater environment is within 5m of the seabed, preferably within 20m of the seabed, preferably 50m of the seabed.

Preferably the underwater object is entirely submersed.

The uv directed onto the object may be in the range of 100-500nm, preferably 350-400nm.

Preferably the object comprises a surface which is suitable to interact with the uv light, that is convert the uv light into visible light, hereinafter referred to as being "uv reactive". The surface may comprise a suitable coating or paint. Such a coating may be obtained from Jotun (wwwotun.com) under the brand name Balloxy HB Lumi. Therefore a uv reactive paint may be applied to the surface of the underwater object for it to function with certain embodiments of the invention.

Thus according to a second aspect of the invention there is provided a method of manufacturing an underwater object, the method comprising coating a surface of the underwater object with a uv reactive paint.

The underwater object may comprise at least one of a number of different items of underwater equipment such as wellheads, remotely operated vehicles (ROV5), tubulars, blow-our preventors (BOP5), subsea christmas trees, manifolds, pipelines, protection structures, clump weights, anchors, subsea deployed lifting rigging, flowbases, autonomous underwater vehicles (AUV5), subsea risers, subsea intervention tools, subsea repair clamps, removable or replacement items for any of the above.

In preferred embodiments, the underwater object is a tool used in the exploration or recovery of hydrocarbons from subsea reservoirs.

According to a third aspect of the invention there is provided a method of using an underwater object, the method comprising coating a surface of the underwater object with a uv reactive paint; then deploying the object underwater.

Typically the object is deployed to a depth of at least I Om, preferably at least 20m and may be deployed to any depth as required, such as more than 50m or even more.

The method according to any previous aspect of the invention may include: moving, repairing, altering, joining and/or other work with, to, or involving the underwater object; and so one aspect of the invention is a method of working underwater.

According to a fourth aspect of the present invention, there is provided an illuminating apparatus comprising a uv light in a housing, the apparatus being suitable to be used at a pressure of at least 100 bar.

Preferably the uv light is suitable for use at pressures of above 200 bar, preferably above 400 bar. Thus with such a pressure rating the uv light of the fourth aspect of the present invention may be used in the methods according to the earlier aspects of the invention.

A uv light source may be obtained from a number of suppliers, such as Philips Lighting UK -Guildford, Surrey, UK or Osram Ltd Langley, UK.

Typically the housing has a transparent panel to allow the uv light from the light source to be emitted from the apparatus. Such a transparent panel is uv-trans missive.

Preferably the light source is a high power light source that is capable of emitting uv light at a power of at least 50 watts, preferably at least 400 watts.

The uv light can be used for viewing and overall illumination of underwater objects and equipment.

The light can be powered externally or internally from stored power and can be mounted to a diver or remotely operated vehicle as well as being hand held.

Any feature of any aspect of any invention or embodiment described herein may be combined with any feature of any aspect of any other invention or embodiment described herein mutatis mutandis.

An embodiment of the present invention will now be described, by way of example only, with reference to figure 1 which is a view of one embodiment of the method and apparatus in accordance with the present invention.

A Remotely Operated Vehicle (ROV) 10 comprises thrusters 12, grappling arms 14 and a camera 16. To illuminate the underwater object, in this case a wellhead 50, visible lights 18 and ultraviolet (uv) lights 20 are provided.

The wellhead 50 is coated in uv reactive paint.

In use the visible lights 18 are directed towards the wellhead 50. On the occasion where suspended particles 22 are present, the visible light will be reflected back to the camera 16 causing glare and obscuring the wellhead 50.

Thus the uv light 20 is operated and uv light is directed towards the wellhead 50.

Whilst some uv light is reflected back to the camera 16, this will not cause glare or obscure the wellhead 50 because it is not in the visible range. When the uv light reaches the wellhead 50, the uv reactive paint causes the light to become visible light, to "glow" and so illuminate the wellhead 50.

In this way, the operator can see the wellhead 50 (which would otherwise be obscured) and the work may progress thereon.

Improvements and modifications may be made without departing from the scope of the invention.

Claims

Claims 1. A method of illuminating underwater objects, the method comprising: in an underwater environment, directing ultraviolet light onto the underwater object, such that the ultraviolet light interacts with the object to produce visible light.
2. A method as claimed in claim 1, wherein the uv directed onto the object is in the range of 10-400nm.
3. A method as claimed in either preceding claim, wherein the object comprises a uv reactive surface.
4. A method as claimed in any preceding claim, wherein the underwater environment is at least 20m deep, preferably at least 50m deep.
5. A method as claimed in any preceding claim, wherein the ultraviolet light is directed from a light source held by or connected to a diver.
6. A method as claimed in any of claims I to 4, wherein the ultraviolet light is directed from a light source mounted to a Remotely Operated Vehicle (ROV).
7. A method as claimed in any preceding claim, wherein the underwater environment is within 5m of the seabed.
8. A method as claimed in any preceding claim, wherein the underwater environment is within 20m of the seabed.
9. A method as claimed in any preceding claim, wherein the underwater environment is within 50m of the seabed.
10. A method as claimed in any preceding claim, wherein the underwater object is a tool used in the exploration or recovery of hydrocarbons from subsea reservoirs.
11. A method as claimed in any one of claims I to 9, wherein the underwater object comprises at least one from the list consisting of wellheads, remotely operated vehicles (ROV5), tubulars, blow-our preventors (BOP5), subsea christmas trees, manifolds, pipelines, protection structures, clump weights, anchors, subsea deployed lifting rigging, flowbases, autonomous underwater vehicles (AUV5), subsea risers, subsea intervention tools, subsea repair clamps, and removable and replacement items for said objects.
12. A method of manufacturing an underwater object, the method comprising coating a surface of the underwater object with a uv reactive paint.
13. A method as claimed in claim 12, wherein the underwater object comprises at least one from the list consisting of wellheads, remotely operated vehicles (ROV5), tubulars, blow-our preventors (BOP5), subsea christmas trees, manifolds, pipelines, protection structures, clump weights, anchors, subsea deployed lifting rigging, flowbases, autonomous underwater vehicles (AUV5), subsea risers, subsea intervention tools, subsea repair clamps, and removable and replacement items for said objects.
14. A method of using an underwater object, the method comprising coating a surface of the underwater object with a uv reactive paint; then deploying the object underwater.
15. A method as claimed in claim 14, wherein the object is deployed to a depth of at least lOm, preferably at least 50m.
16. An illuminating apparatus comprising a uv light in a housing, the apparatus being suitable to be used at a pressure of at least 100 bar.
17. Apparatus as claimed in claim 16, wherein the uv light is suitable for use at pressures of above 200 bar, preferably above 400 bar.
18. Apparatus as claimed in claim 16 or claim 17, wherein the housing comprises a uv-transmissive panel.
19. Apparatus as claimed in any one of claims 16 to 18, wherein the light source emits uv light at at least 50 watts.