GB2253115A - Remotely controlled television camera inspection system - Google Patents

Abstract

A remotely-controlled camera inspection system suitable for sub-sea use has a tubular main body 10 in which is slid ably mounted a piston 18 having a downwardly-projecting piston rod 20. A pump 15 may lower or raise the piston by pumping ambient fluid into or out of the space above the piston. A marinised CCD camera 22 is mounted on the lower end of the piston rod by a mounting unit 21 which is motorised to permit the camera to be rotated through 360 DEG of arc about the axis of the piston rod 20. The unit 21 has an arm 23 which carries the camera, which arm is mounted for turning movement about a horizontal axis. A light ring 24 is arranged around the camera objective to direct light along the optical axis thereof, and a second light ring 25 is provided around the lower end of the main body, to direct light along the axis thereof. The inspection system may be connected to an umbilical which contains conductors for power and control signals as well as for video signals from the camera, or to a drill string or other equipment for lowering of the camera to the zone of interest. <IMAGE>

Description

REMOTELY-CONTROLLED CAMERA INSPECTION SYSTEM This invention relates to a remotely-controlled camera inspection system particularly but not exclusively suitable for use within a subterranean bore-hole, such as within an oil-well casing in whatever fluid may be encountered within that casing, or for use more generally in an under-water environment. Such a camera inspection system suitable for use in a bore-hole or under-water, for attachment to a tool string, umbilical or other equipment, will hereinafter be referred to as a camera inspection system "of the kind described".

In recent years, there has been a most significant growth in off-shore oil and gas installations, which has led to a substantial requirement for inspection systems for use within a bore-hole, to permit viewing of the casings installed in the bore-hole and also of any other equipment located therein. There is a particular need for an inspection system which can be used to inspect the interior of tubulars, well heads, mud line suspensions, ancillary well equipment and/or a bore-hole created by the use of a tubular.

A known system commonly used for the inspection of a bore-hole comprises a silicon intensified tube (SIT) camera mounted on the end of an elongate substantially cylindrical control pipe, often referred to as an "umbilical tube". Due to the relatively confined space within the bore-hole, the known system can generally only be used in a fixed orientation relative to the control pipe, in which the camera looks axially forwardly of that pipe, or laterally thereof. If a more general inspection of the bore-hole is required, then a mirror can be provided adjacent the camera lens, the mirror being mounted at approximately 45" to the camera axis, to allow lateral viewing. It has also been proposed to mount such a mirror for rotational movement about the camera axis, to allow viewing in any radial direction of the bore-hole.

The above described system is cumbersome and prone to breakdowns. A SIT camera, especially when marinised, is generally speaking too large for use in the relatively confined space of a bore-hole, and this then gives rise to the further difficulty of providing a sufficient light source for the camera. Also, the mirror and its mounting arrangement are succeptable to damage since these items are at the forward end of the control tube.

Another known inspection system for working at relatively great depths (typically 1000 to 3500m) is extremely long and associated with a high degree of complexity. The rigging and running of this system is of necessity time consuming, which makes it commercially unattractive for shallow depth work.

Often the physical dimensions of the camera and running equipment precludes its use, in any event.

It is a principal aim of the present invention to provide an improved remotely controlled camera inspection system of the kind described, and so particularly suitable for use within a bore-hole, such as within an under-sea oil well tubular or casing or for open-water work, and which is compact and relatively easy to use, thus enabling a rapid inspection of the zone of interest, with a minimum of operating down-time for an oil well, or other associated equipment.

According to the present invention, there is provided a remotely controlled camera inspection system of the kind described, comprising: a generally tubular main body adapted to be suspended within a bore-hole to be inspected; mounting means supporting a remote-control camera on the main body; and a lighting arrangement associated with the camera and adapted to direct light at an object which is being viewed by the camera; the mounting means being operable to move the camera between a first position where the optical axis of the camera is directed generally along or parallel to the axis of the main body and a second position where said optical axis is directed generally along or parallel to a radius of the main body.

In the camera system of this invention, the camera is mounted on the main body of the system in such a way that the camera may be moved to view any required object. Operation of the mounting means permits the camera to be pointed downwardly, along a radial direction, or in any intermediate direction. In this way, the problems associated with the known inspection systems described above may be overcome.

Most preferably, the mounting means is operable to move the camera through substantially 3600 of arc about the axis of the main body. The mounting means may include an arm for supporting the camera, which arm is pivoted directly or indirectly on the main body about an axis lying in a substantially radial plane of the main body. Small electric motors may be furnished within the mounting means, to effect the rotational movement of the mounting means and of the arm. The mounting means may include extending means which is operable to withdraw the camera so as to lie wholly within the main body or to deploy the camera so as to be outside the confines of the main body.For example, the extending means may comprise an hydraulic ram together with a pump arranged to pump hydraulic fluid into and out of the ram - and most conveniently, the ram is extended and contracted by pumping the external ambient fluid, which may be for example sea-water or oil.

Illumination for the camera may be provided by a light ring disposed adjacent the camera objective lens and arranged to direct light along the camera optical axis. In addition, there may be a light ring around the lower end of the tubular main body and arranged to direct light along the axis of that body. The camera may take the form of a miniature charge-coupled device (CCD), which, apart from its small dimensions, is adapted to operate in low light intensities. The camera should be marinised, for operation sub-sea, typically down to a depth of 250 m.

The inspection system may be suspended from an umbilical containing the required conductors for electrical power, control of the system, and video signals. An amplifier and distribution unit may be provided within or on the main body, to process the control and video signals; in this way the number of conductors within the umbilical may be reduced and the image quality improved. Alternatively the required amplification may be performed at the surface, where a control console for the camera and mounting means should be provided.

This invention extends to a camera inspection system of this invention as described above, in combination with an umbilical connected at one end to the system for the suspension thereof and the conduction of electrical signals to and from the system, and a control means connected to the other end of the umbilical, for supplying control signals to the inspection system and for processing video signals received from the inspection system.

By way of example only, one specific embodiment of a remote controlled camera inspection system primarily intended for use in a bore-hole and constructed according to the present invention will now be described in detail, reference being made to the accompanying drawings, in which: Figure 1 is a diagrammatic vertical sectional view through said embodiment of this invention; Figure 2 is a partial vertical sectional view on the embodiment of Figure 1 but with the plane of section being at 900 to that of Figure 1 and with the camera viewing downwardly; and Figure 3 is a lower end view on the camera inspection system, with the camera in the position shown in Figure 2.

The embodiment of camera inspection system shown in the drawings is intended for use in a sub-sea oil or gas well, for inspecting equipment already fitted into the bore-hole, such as the casings, associated threads and connectors and so on. The system may also be used for monitoring operations in open water, for instance for the guidance of tools or other equipment, or to inspect any subterranean or sub-sea object which may be encountered in association with an oil or gas well. To this end, the inspection system permits viewing both axially of the drilling equipment, and laterally thereof.

The camera inspection system comprises a main body 10 of a tubular form and fitted with an end plate 11 at is upper end. The lower end of the main body 10 is open, and a number - typically four - of rectangular openings 12 are formed equally spaced around the periphery of the main body, adjacent that lower end.

Fitted centrally to the end plate 11 is an electrical connector part 13 adapted to mate with a complementarily-formed connector part (not shown) to permit the making of a plurality of electrical connections in a fluid-tight manner, having regard to the particularly hostile environment which may be found down a well. The connector part 13 is of a strength sufficient to support the weight of the inspection system, whereby the entire apparatus may be suspended from an electrical cable (not shown) coupled to the connector part 13. Such an electrical suspension cable is commonly referred to in the art as an "umbilical".

Within the main body 10 and spaced from the end plate 11 is a mounting plate 14 which supports an electrically-driven fluid pump 15 together with associated solenoid valves (not shown). The pump 15 has inlet and outlet pipes 16 and 17 respectively, which lead to the external ambient through the end plate 11.

Slidably mounted within the main body 10, below the mounting plate 14, is a piston 18 having an elongate skirt 19 whereby the piston is prevented from becoming misaligned and jamming within the main body 10. Depending axially downwardly from the piston 18 is a piston rod 20, which carries on its lower end a mounting unit 21 for a charge-coupled device (CCD) inspection camera 22. The mounting unit is motorised so that it may turn about the axis of the piston rod 20, as shown by the arrow 'A' in Figure 1. The unit 21 has an arm 23 which carries the camera 22, the unit having a second motor arranged to turn the arm 23 about a horizontal axis, as shown by arrow 'B' in Figure 1.

The camera 22 has a light ring 24 provided around its objective lens and arranged to direct light forwardly along the camera optical axis, so as to illuminate the field of view of the camera. In addition, a significantly larger light ring 25 is provided on the lower end of the main body 10, the individual lighting elements 26 of which ring are individually adjustable or are pre-set to direct the light as required - but this light ring 25 directs light generally downwardly, along the axis of the main body 10.

Electrical power and signal cables for the light rings, camera, pump and solenoid valves all terminate in the connector part 13. A festoon arrangement 27 for those cables coupled to the piston 18 is provided on the underside of the end plate 11, with the cables extending through an aperture 28 in the mounting plate 14. Thus, as the piston is moved downwardly from the position illustrated in Figure 1, the electrical integrity between the connector part 13 and the camera is maintained.

In use, the inspection system described above is connected to an umbilical by means of which the inspection system may be suspended and lowered down a bore-hole. If required, the umbilical may connect to an electronics unit 30 which in turn is connected to the connector part 13, to permit amplification and perhaps also multiplexing of the signals to and from the system, to minimise problems which may be caused by the length of the umbilical. However, for some installations the electronics unit may be provided at the upper end of the umbilical. For some inspection, guidance or locating purposes, the inspection system may instead be attached to or mounted on a tool string or other piece of equipment.

For sub-sea stabbing or object locating operations, the inspection system would normally be lowered with the camera in the downward-viewing position (Figures 2 and 3), protected by the main body 10. The light ring 25 would be energised, to provide illumination for objects at a distance of typically 0.5 to 5 metres from the main body. When the object being searched has been located, the pump 15 may be operated to pump the ambient fluid into the space between the end plate 11 and the piston 18, thereby driving the piston downwardly to deploy the camera 22 beyond the light ring 25. Then, the camera may be precisely positioned to view the object of interest, by operating the mounting unit 21 to move the camera as required, as shown by arrows A and B. A stop ring 31 is disposed within the main body to prevent the piston 18 from moving out of the main body.

On completion of the inspection, the solenoid valves are appropriately operated and the pump 15 powered once more, to withdraw fluid from the space between the end plate 11 and the piston 18, thereby drawing the piston 18 upwardly and locating the camera 23 once more within the main body 10. Thereafter, the inspection system may be retrieved to the surface, by the umbilical, -or by the drill string or other equipment, as appropriate.

For certain objects to be inspected - for example, a joint between two casing parts - the camera may be positioned as shown in Figure 1, so as to view through one of the openings 12. In this case, the light ring 24 would be energised during the lowering of the system, whereby the sides of the casing are illuminated to permit location of the joint. In large-diameter casings, supplementary lighting may be achieved by using the light ring 25, as well. Once located, it may be possible adequately to view the joint with the camera remaining in the main body 10; in the alternative, the camera may be deployed as described above and then accurately positioned in order to inspect the exact part of interest of the joint.

It will be appreciated that all of the inspection operations are witnessed and controlled from the surface, using a surface control unit (not shown) which may incorporate real-time monitoring and a recording unit. The vertical position of the system may be controlled by means of a winch associated with the umbilical and which may be provided, for example, on the drill floor of a well platform.

The described camera inspection system of this invention allows for a rapid inspection of sub-sea objects, tools or other equipment, at relatively shallow depths. The operating costs for a drilling rig are most significant and the use of a bulky or complex inspection system would be precluded either by space constraints or commercial considerations; the inspection system of the present invention mitigates these difficulties.

Claims (13)

1. A remotely-controlled camera inspection system of the kind described, comprising: a generally tubular main body adapted to be suspended within a bore-hole to be inspected; mounting means supporting a remote-control camera on the main body; and a lighting arrangement associated with the camera and adapted to direct light at an object which is being viewed by the camera arrangement; the mounting means being operable to move the camera between a first position where the optical axis of the camera is directed generally along or parallel to the axis of the main body and a second position where said optical axis is directed generally along or parallel to a radius of the main body.

2. A camera inspection system according to Claim 1, wherein the mounting means is operable to move the camera through substantially 3600of arc about the axis of the main body.

3. A camera inspection system according to Claim 1 or Claim 2, wherein the mounting means includes an arm for supporting the camera and which is pivoted directly or indirectly on the main body about an axis lying in a substantially radial plane of the main body.

4. A camera inspection system according to any of the preceding Claims, wherein the mounting means includes extending means which is operable to withdraw the camera so as to lie wholly within the main body or to deploy the camera so as to be outside the confines of the main body.

5. A camera inspection system according to Claim 4, wherein the extending means comprises an hydraulic ram together with a pump arranged to pump hydraulic fluid into and out of the ram.

6. A camera inspection system according to Claim 5, wherein the pump is arranged to draw fluid from the external ambient to expand the ram and to discharge fluid to the external ambient to contract the ram.

7. A camera inspection system according to Claim 5 or Claim 6, wherein the main body defines the cylinder of the hydraulic ram, the ram having a piston rod which extends from the ram piston and the camera being mounted on the free end of said rod remote from the piston.

8. A camera inspection system according to Claim 7, wherein a mounting unit for the camera is provided on the free end of the piston rod. The mounting unit being rotatable about the axis of the piston rod and having an arm rotatable about an axis transverse to the piston rod axis, the camera being mounted on said arm.

9. A camera inspection system according to any of the preceding claims, where in there is provided a light ring disposed adjacent the camera objective lens and arranged to direct light along the camera optical axis.

10. A camera inspection system according to any of the preceding claims, wherein there is provided a light ring around the lower end of the tubular main body and arranged to direct light along the axis of that body.

11. A camera inspection system according to any the preceding claims, where in the main body has at least one opening through the side wall thereof, adjacent the lower end, whereby the camera may be positioned to view laterally of the main body whilst still located therewithin.

12. A remotely-controlled camera inspection system substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

13. A remotely-controlled camera inspection system according to any of claims 1 to 12 in combination with an umbilical connected at one end to the system for the suspension thereof and the conduction of electrical signals to and from the system, and a control means connected to the other end of the umbilical, for supplying control signals to the inspection system and for processing video signals received from the inspection system.