WO2005069603A1

WO2005069603A1 - A camera system

Info

Publication number: WO2005069603A1
Application number: PCT/GB2005/000083
Authority: WO
Inventors: Jonathan James Renton Thursby; David Daniel Clover
Original assignee: Ev Offshore Limited
Priority date: 2004-01-17
Filing date: 2005-01-17
Publication date: 2005-07-28
Also published as: GB0401044D0

Abstract

A camera system, comprises a camera head incorporating means for capturing images, characterised in that the system comprises an active heat exchanger which when the camera head is submerged in a liquid uses the liquid itself as a coolant.

Description

A CAMERA SYSTEM

Field of the Invention

The invention relates to camera systems and particularly to camera systems which operate in fluid environments under high pressure and temperature conditions.

The invention has particular applications in the field of oil drilling.

Background to the Invention and Prior Art known to the Applicants

Current camera systems used in the oil industry are attached at the end of a co-axial cable. The systems capture images in submersed conditions at relatively high pressures but are capable only of producing top views in black and white with only a few frames per second.

One of the objectives of the present invention is to provide a system which may withstand temperatures in the region of 150°C for a period of 4 hours.

A further objective of the invention is for the camera system to withstand pressure in the region of 12,500 p.s.i. A further objective of the invention is to provide colour video footage in 'real time'.

A further objective of the invention is to provide images at a variety of angles (i.e. not simply plan views).

A further objective of the invention is to illuminate the area being filmed.

A further objective is to incorporate auxiliary modules such as a gas sensor.

A further objective of the invention is to render the camera capable of withstanding corrosive and abrasive environments.

Summary of the Invention

In a first broad independent aspect, the invention provides a camera system, comprising a camera head incorporating means for capturing images, characterised in that the system comprises an active heat exchanger which, when the camera head is submerged in- a liquid, uses the liquid itself as a coolant.

This particular camera system is advantageous because it will achieve advantageous cooling of the camera head and would therefore allow its operation within higher temperature environments than those in which conventional camera heads operate. Since the cooling medium is the liquid itself, the system is also particularly efficient.

In a subsidiary aspect the heat exchanger has a liquid inlet remotely located from the camera head. This configuration would allow a greater degree of cooling to be achieved and would therefore be advantageous.

In a second broad independent aspect, the invention provides a camera system comprising a camera head incorporating means for capturing images and adapted for submersion in a liquid, a remote camera controller and a means for transmitting images from the camera head to the remote controller characterised in that the camera head incorporates light emitting diodes acting as a light source in submerged locations allowing the capturing of images.

This configuration is particularly advantageous because it would allow improved quality images to be captured without greatly increasing the power consumption requirements of the camera system.

In a third broad independent aspect, the invention provides a camera system comprising a camera head incorporating means for capturing images, a remote camera controller and a cable for transmitting images from the camera head to the remote controller, characterised in that the camera head incorporates an optical element which displaces relative to the cable in order to allow it to capture images at a plurality of angles.

This marks a complete departure from the prior art teaching that such camera heads only capture a plan view image. This would allow the capturing of images at angles selected by the operator to capture more relevant images for given purposes.

In a subsidiary aspect in accordance with the invention's third broadest aspect, the optical element is a mirror which displaces under remote control. In this configuration, it would for example not be necessary to have to displace the lens of the camera to capture images at a plurality of angles.

In a further subsidiary aspect in accordance with the invention's fourth broad aspect, the optical element is a prism. This configuration would allow the beneficial control of the capturing of images .

In a fourth broad independent aspect, the invention provides a camera system comprising a camera head incorporating means for capturing images, a remote camera controller and means for transmitting images from the camera head to the remote controller, wherein the system further comprises a gas and/or temperature and/or pressure and/or flow sensor. This combination of features would allow advantageous data to be captured in order to preserve the camera head from excessive damage and wear dependent on the parameters assessed by these sensors.

hi a fifth broad independent aspect, the invention provides a camera system comprising a camera head incorporating means for capturing images and adapted for submersion in a liquid, a remote camera controller and a cable for transmitting images extending from the camera head to the remote controller, wherein the camera head operates alongside means to collect samples.

This unique combination of features will provide the operator of the camera system with improved means to control the operation of the camera itself and improved material to generate analysis data.

hi a sixth broad independent aspect, the invention provides a camera system comprising a camera head incorporating means for digitally capturing images, a remote camera controller and means for transmitting images from the camera head to the remote controller, the camera head incorporating compression means to compress the image and means to modulate the image to be transferred over a co-axial cable to the controller and the controller comprising means to demodulate the image into a digital image, characterised in that the compression means are selected to allow the transmission of colour images.

h this configuration, more accurate images may be captured which would ameliorate the further analysis of images.

Brief Description of the Figures

Figure 1 shows a schematic perspective view in a drilled hole in accordance with a first embodiment of the invention.

Figure 2 shows schematically a part of a camera system in a drilled hole in accordance with a second embodiment of the invention. Figure 3 shows schematically a further part of a camera system in a drilled hole in accordance with a third embodiment of the invention.

Detailed Description of the Figures

Figure 1 shows a submerged part of a camera system generally referenced 1 located in a drilled hole say of approximately 50mm in diameter. The walls of the drilled hole are represented by lines 2 and 3. A fluid at a pressure of 12,500 p.s.i may surround the camera head 4 in use at a temperature of say 150°C. The critical electronic components of the camera may be protected by a housing of non-corrosive material such as stainless steel incorporating a high chromium content. Certain components of the camera head which are exposed to the highest temperatures may be of beryllium copper for extra heat resistance.

Releasable attachment means may be provided between camera head 4 and cable 5 which may be a standard co-axial cable. A fluid conduit 6 may run up alongside the co-axial cable 5 with an inlet located several feet above the camera's head. Means may be provided to circulate fluid via conduit 6 and about heat sensitive elements of the camera head to provide cooling to those elements particularly when the camera head is plunged into high temperature environments.

The invention also envisages the use of other forms of heat exchangers providing the necessary cooling of the camera head, one such example may be a Peltier cooler if appropriate in a particular application as determined by the person skilled in the art.

Figure 2 shows a second embodiment of a submerged part generally referenced 7 of a further camera system in accordance with a second embodiment of the invention. The walls of the drilled hole are similar to those of Figure 1, illustrated by references 2 and 3. A co-axial cable 5 is also shown leading to camera head 8. Means are provided to displace camera head 8 in a variety of angles with reference to the co-axial cable's line. An articulated joint 9 allows the head to change its direction under remote control. A number of EDs may be provided to illuminate the region where the camera is capturing images. The camera will of course incorporate the necessary lens which may operate in conjunction with means to remotely control the position of the lens in order to adjust its focus.

Figure 3 shows a further embodiment of a part of a camera system when submerged in a drilled hole, the part of the camera system being generally referenced 10. Identical components to those described in Figures 1 and 2 have kept identical numerical references. Part 10 incorporates a camera head 11 from which an arm 12 extends and acts as a means to pivot a mirror 13 which can be used to capture images at a variety of angles.

The camera head 11 may also incorporate a sensor such as that referenced 14. The sensor may for example be a piezoelectric pressure sensor for sensing the pressure at the camera's location. The system may also comprise a gas and/or temperature and/or flow sensor, dependent on the particular analysis which the operator would like to conduct with his/her camera system. In this embodiment the optical element allowing the capture of images at a plurality of angles was selected as a pivoting mirror, alternatively an appropriate refractor may be selected such as a prism.

The camera head may also incorporate means to collect samples. This may for example be achieved by constructing a chamber with aspiration means to aspirate a surrounding fluid.

The parts of the camera system illustrated in Figures 1 to 3 would operate in conjunction with a remote camera controller which could include means to display in 'real time' the images as they are captured. The remote camera controller may be itself enshrouded in a waterproof housing to prevent any liquid potentially damaging the control electronics.

The camera head incorporates compression means which could compress the image data using for example so-called 'MPeg' compression technology. A modulator may also be provided to allow the digital information to be carried by an analogue cable. The remote controller would be equipped with an appropriate demodulator to convert the digital infonnation carried by the analogue signal into a digital image. Features of the embodiments described include:

Digital video to 30,000 feet (approximately, say, 10 kilometres).

Digital compression of a component video signal to a rate of around 200 kbit/s. Protected with an advanced error correcting code which ensures that we can approach very closely the theoretical capacity of the cable to carry information.

A rugged digital modulation system which carries the signal in a very low bandwidth.

Automatically lowering the video frame-rate to increase picture resolution. For most inspection-type applications, where there is little rapid movement, it is spatial resolution which is of most importance so we retain this in favour of high-speed motion portrayal (of course, the dropped frames will be interpolated back so no disturbing flicker will result).

At the surface we amplify and adaptively equalise the received signal and then apply the error correction decoder, video decoder and error concealment (should any errors not be correctable). All control data sent up from the camera is demultiplexed out at this point. The video output is then interpolated to a full 720 x 576 signal for display. The video processing takes place within DSP devices.

Having a compressed digital signal, offers opportunities which analogue ones do not. We can store the compressed digital video onto a hard disc rather than current DN recorder.

Claims

1. A camera system, comprising a camera head incorporating means for capturing images, characterised in that the system comprises an active heat exchanger which when the camera head is submerged in a liquid uses the liquid itself as a coolant.

2. A system according to claim 1, wherein the heat exchanger has a liquid inlet remotely located from the camera head.

3. A camera system, comprising a camera head incorporating means for capturing images and adapted for submersion in a liquid, a remote camera controller and means for transmitting images from the camera head to the remote controller, characterised in that the camera head incorporates light emitting diodes acting as the light source in submerged locations allowing the capturing of images.

4. A camera system, comprising a camera head incorporating means for capturing images, a remote camera controller and a cable for transmitting images from the camera head to the remote controller, characterised in that the camera head incorporates an optical element which displaces relative to the cable in order to allow it to capture images at a plurality of angles.

5. A system according to claim 4, wherein the optical element is a mirror which displaces under remote control.

6. A system according to claim 4, wherein the optical element is a prism.

7. A camera system, comprising a camera head incorporating means for capturing images, a remote camera controller and means for transmitting images from the camera head to the remote controller, wherein the system further comprises a gas and/or temperature and/or pressure and/or flow sensor.

8. A camera system, comprising a camera head incorporating means for capturing images and adapted for submersion in a liquid, a remote camera controller and a cable for transmitting images extending from the camera head to the remote controller, wherein the camera head operates along side means to collect samples.

9. A camera system, comprising a camera head mcorporating means for digitally 5 capturing images, a remote camera controller and means for transmitting images from the camera head to the remote controller, the camera head incorporating compression means to compress the image and means to modulate the image to be transferred over a coaxial cable to the controller, and the controller comprising means to demodulate the image into a digital image, characterised in that the compression means are selected to allow the o transmission of colour images.

10. A camera system substantially as hereinbefore described with reference to and/or illustrated in any appropriate combination of the accompanying text and/or figures. 5

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