FIELD OF THE INVENTION

This invention relates to a downhole tool for manipulating a broken element of a downhole safety valve. In particular, this invention relates to a downhole tool for the manipulation of a flapper of a flapper-type safety valve.

BACKGROUND TO THE INVENTION

Subsurface safety devices are often included in both onshore and offshore wells. These safety devices may be used to control fluid flow and isolate part of the well. One such subsurface safety device is a downhole safety valve.

A common type of downhole safety valve is a uni-directional flapper valve. These open in a downwards direction so that pressure from an upward flow of fluid from the well acts to close the valve and thereby isolate the fluid from the surface.

Downhole safety valves, such as flapper valves, may, however, be damaged during downhole operations such as, for example, deployment of a downhole tool through the valve. This may occur, for example, if pressures either side of the valve are not sufficiently equalised or if the speed of the downhole tool is too great. In the case of flapper valves it is known for the hinge pin, about which the flapper rotates, to shear. The flapper then falls to the bottom of the safety valve, below the original operational position of the flapper valve. Often the flapper will seat on a shoulder such that the flapper effectively blocks passage through the valve.

If this occurs it is not possible to retrieve the flapper as the diameter of the flapper is larger than the inner diameter of the top of the safety valve. It is therefore necessary to manipulate the flapper into a non-obstructing position. In particular, the flapper needs to be manipulated back into a flapper window. The flapper window may be disposed at a variety of different distances above the bottom of the safety valve, and may be disposed, for example, between 5 cm and 60 cm above the bottom of the safety valve. Once the flapper is in the flapper window, flow tubes which extend through the valve can be activated to “lock” the flapper in place. A sleeve or a wireline safety valve can then be run in lieu of this now inactive safety valve.

It will be appreciated that it may be difficult to locate the damaged flapper valve, and the internal design and configuration of safety valves varies depending on the manufacturer and model. Known tools exist to try and rotate the flapper and position it back into the flapper window; however, these known tools have significant shortfalls. In particular, there is often no way to tell in which azimuth the tool is facing relative to the flapper window within the safety valve. This results in pure chance being relied upon to eventually manipulate the flapper into the correct position. Due to this, operations can take days or weeks or, in some cases, operators have to abandon the operation before it is completed.

Against this background it is desired to provide an improved downhole tool for the manipulation of an obstructing object such as a flapper.

SUMMARY OF THE INVENTION

A first aspect of the invention provides a manipulation element for a downhole tool, the downhole tool comprising a camera assembly including a lens, and the manipulation element comprising: a root portion connectable to said downhole tool, the root portion including an aperture for receiving a part of the camera assembly therethrough such that, in use, said lens is disposed forward of the root portion; a stem portion extending from the root portion and including a hollow or gap aligned with the aperture for receiving, in use, said lens, the stem portion terminating at a tip; and a manipulation surface extending continuously between the tip and the root portion, at least a part of the manipulation surface extending at a non-zero angle to a longitudinal axis of the manipulation element such that the manipulation surface crosses a plane containing the longitudinal axis.

The manipulation element is preferably of unitary or one-piece construction. The manipulation element is preferably made of a metal material or a composite material.

The root portion may include an attachment portion configured to attach the manipulation element to the downhole tool. The attachment portion may include a threaded portion.

The tip is preferably offset from longitudinal axis. In preferred embodiments the longitudinal axis is unobstructed. It is preferable if no part of the stem portion lies on the longitudinal axis. It is preferable if no part of the stem portion forward of the wide angle lies on the longitudinal axis.

The lens is preferably a wide angle lens. The lens may be a fish-eye lens.

In some embodiments the stem portion is in the form of a hollow cylindrical wedge and the manipulation surface is provided by an edge surface of the hollow cylindrical wedge. The hollow may be at least partially bounded by a curved inner surface of the stem portion.

In other embodiments the tip may be part of a tip portion of the manipulation element and the stem portion may comprise a pair of arms extending between the root portion and the tip portion.

The arms are preferably elongate. The arms preferably extend substantially parallel to the longitudinal axis. In preferred embodiments the arms are tapered. A first surface of each of the arms may extend generally parallel to the longitudinal axis. A second surface of each of the arms may extend at a non-zero angle to the longitudinal axis.

The tip portion of the manipulation element preferably connects distal ends of the arms. The tip portion may comprise curved inner and outer surfaces. A centre of a radius of curvature of each of the inner and outer surfaces may lie on or proximate the longitudinal axis. The tip portion may have the shape of a hollow cylindrical wedge. The tip portion may include a U-shaped forward-facing surface, facing generally in a direction away from the root portion. Preferably the U-shaped forwardfacing surface is continuous with the second surfaces of each of the arms.

The manipulation surface preferably includes the forward-facing surface of the tip portion and the second surfaces of each of the arms. The manipulation surface may be planar. The manipulation surface may be partially or continuously curved.

A second aspect of the invention provides a downhole tool comprising: a camera assembly including a camera and a lens; and a manipulation element according to the first aspect of the invention, wherein, the lens is disposed in the hollow or gap of the stem portion.

The camera is preferably a video camera. The video camera may be a high definition video camera. The camera may capture colour images. The lens may be part of a group of lenses. The lens or group of lenses preferably have a wide angle field of view. The lens may be a wide angle lens.

Preferably a centreline of a field of view of the camera is parallel to and coincident with the longitudinal axis of the manipulation element. In some embodiments at least a part of the arms and a part of the tip portion of the manipulation element is within the field of view of the camera.

The manipulation surface preferably extends from a first end forward of the lens to a second end rearward of the lens.

The camera assembly preferably includes one or more light sources for illuminating the field of view of the camera. The light source or light sources may be disposed between the lens and the root portion of the manipulation element. The downhole tool preferably includes a transmitter for transmitting images captured by the camera in real time. The downhole tool is preferably deployed on a wireline or fibre optic line but may be deployed on drillpipe, coiled tubing or e-coil or a derivative of such.

The downhole tool preferably includes a motor, such as an electric motor, and a mechanism for rotating the manipulation element about the longitudinal axis. The mechanism may be configured to permit rotation of the manipulation element through 360° about the longitudinal axis.

A third aspect of the invention provides a method of locating and manipulating an obstructing object in a downhole environment using a downhole tool according to the second aspect of the invention, the method comprising: viewing, in real time, a region forward of the manipulation element while moving the downhole tool through the downhole environment to locate said obstructing object; contacting the tip of the manipulation tool on said obstructing object; moving the downhole tool so as to cause the obstructing object to slide along the manipulation surface in a direction towards the root portion.

The method preferably further comprises rotating the manipulation element about the longitudinal axis.

The method may comprise moving the downhole tool so as to bring the lens alongside the obstructing object. The method may comprise moving the downhole tool so that a surface of the root portion contacts the obstructing object.

Preferred and/or optional features of each aspect and embodiment described above may also be used, alone or in appropriate combination, in the other aspects and embodiments also. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further described by way of example only and with reference to the accompanying drawings, in which like reference signs are used for like features, and in which:

Figures 1 and 2 are perspective views of a manipulation element in accordance with a first preferred embodiment of the invention;

Figure 3 is a side view of the manipulation element of Figure 1 ;

Figure 4 is a cross-sectional view of the manipulation element along the line IV-IV of Figure 3;

Figure 5 is a perspective view of a manipulation tool, including the manipulation element of Figure 1 , in accordance with a second preferred embodiment of the invention;

Figure 6 is a side view of the manipulation tool of Figure 5;

Figures 7 and 8 are further perspective views of the manipulation tool of Figure 5;

Figure 9 is a plan view of the manipulation tool of Figure 5 showing a viewing window of the manipulation tool;

Figure 10 is a plan view of the manipulation tool of Figure 5 showing a manipulation surface;

Figure 11 is a cross-sectional view of the manipulation tool along the line XI-XI of Figure 6;

Figure 12 is an end view from a forward end of the manipulation tool of Figure 5; Figures 13 and 14 are perspective views of a manipulation tool, including a manipulation element, in accordance with a third preferred embodiment of the invention;

Figure 15 shows the manipulation tool in accordance with the embodiment shown in Figures 5 to 11 in a first step in a method of manipulating a position of a flapper in a safety valve;

Figure 16 shows the manipulation tool in accordance with the embodiment shown in Figures 5 to 11 in a second step in the method of manipulating a position of a flapper in a safety valve; and

Figure 17 shows the manipulation tool in accordance with the embodiment shown in Figures 5 to 11 in a third step in the method of manipulating a position of a flapper in a safety valve.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A manipulation element in accordance with the present invention is configured to be attached to or form part of a downhole toolstring or downhole camera assembly. The manipulation element may be used to push or manipulate an obstructing object to clear a passage through a downhole environment, such as in a well casing for example. It is envisaged that the manipulation element of the present invention will find particular utility in manipulating a damaged flapper within a downhole or subsurface safety valve.

Figures 1 to 4 show a first preferred embodiment of a manipulation element 10 in accordance with the present invention. This manipulation element 10 is preferably of unitary or one-piece construction and is preferably made from a suitable metal material.

The manipulation element 10 includes a root portion or collar portion 12 that is configured to attach the manipulation element 10 to a downhole camera assembly or toolstring. In this embodiment the root portion 12 comprises a tubular attachment portion 14 including an external thread 16 for engagement with and attachment to an internal threaded component of the camera assembly or toolstring. The root portion 12 further comprises an annular collar 18. The annular collar 18 extends radially outwardly from the attachment portion 14 and includes a rear surface 20 and an external, circumferential surface 22. In use, the tubular attachment portion 14 is engaged with a part of a camera assembly or toolstring proximate or at a front distal nose portion of the camera assembly or toolstring. The rear surface 20 of the collar 18 preferably abuts a forward-facing surface of the camera assembly or toolstring. The external surface 22 of the collar 18 is preferably continuous or contiguous with an external surface of the camera assembly or toolstring.

In this embodiment a diameter of the collar 18 defined by the external surface 22, defines a maximum external diameter of the manipulation element 10. In this way the manipulation element 10 does not protrude radially beyond an external circumferential surface of the camera assembly or toolstring.

The tubular attachment portion 14 and annular collar 18 together surround and define an aperture 24. In this embodiment the aperture is circular. A body section 26 of the root portion 12 extends from the collar 18 in an opposite direction to the tubular attachment portion 14. A forward-facing surface 28 of the body section 26 includes an aperture 30. In this embodiment the aperture 30 is circular. A bore 32 extends from the aperture 30 through the body section 26 and opens into the aperture 24. A centreline of the bore 32 extending through the body section 26 defines a longitudinal axis 34 of the manipulation element 10.

A stem portion 36 of the manipulation element 10 extends from the root portion 12. In particular, the stem portion 36 extends from the body section 26 of the root portion 12 in a direction away from the collar 18 and attachment portion 14. In this way, in use, when the root portion 12 is attached to the camera assembly or toolstring, the stem portion 36 extends forward of the nose portion of the camera assembly or toolstring. ln this embodiment the stem portion 36 comprises a pair of elongate arms or struts 38. The arms 38 extend generally or substantially parallel to each other. Furthermore, in this embodiment, each of the arms 38 extends generally parallel to the longitudinal axis 34. The arms 38 are spaced apart so as to define a gap 40 between them. The aperture 30 in the body section 26 opens into the gap 40 and is disposed between proximal ends of the arms 38.

Each of the arms 38 includes an inner surface 42 and an opposite outer surface 44. The inner surfaces 42 of the arms 38 face in a direction generally towards each other across the gap 40. Each of the arms 38 further includes a first edge surface 46 and a second edge surface 48.

In this example each of the arms 38 is tapered such that a distance between the first and second edge surfaces 46, 48 at the proximal end of the arms 38 is greater than a distance between the first and second edge surfaces 46, 48 at a distal end of the arms 38. In particular, and as shown most clearly in Figure 3, in this example the first edge surface 46 of each arm 38 extends generally parallel to the longitudinal axis 34 and the second edge surface 48 of each arm 38 extends at a non-zero angle to the longitudinal axis 34.

The arms 38 are joined together at their distal ends to form a tip 50 of the manipulation element 10. As shown most clearly in Figures 1 and 2, a tip portion 52 extends from the distal ends of the arms 38 and bridges the gap 40 between the arms 38. The tip portion 52 comprises an inner surface 54 and an opposite outer surface 56. The inner and outer surfaces 54, 56 of the tip portion 52 extend generally crosswise or substantially perpendicular to the inner and outer surfaces 42, 44 of the arms 38. The tip portion 52 further comprises a rearward-facing surface 58 and a generally forward-facing surface 60. The rearward-facing surface 58 faces generally in a direction towards the root portion 12.

The first edge surfaces 46 of the arms 38, the rearward-facing surface 58 of the tip portion and a forward-facing surface 28 of the body section 26 define a frame around an aperture 64 in the stem portion 36 of the manipulation element 10. In this embodiment the tip portion 52 is in the form of a hollow cylindrical wedge. As such, both of the inner and outer surfaces 54, 56 of the tip portion 52 are curved. In particular, the inner surface 54 has a concave curvature and the outer surface 56 has a convex curvature. Preferably a centre of a radius of curvature of both the inner surface 54 and the outer surface 56 is at the same point and lies on the longitudinal axis 34. The rearward-facing surface 58 has an arc shape or semi-annular shape. The rearward-facing surface 58 forms an arched connection between distal ends of the first edge surfaces 46 of the arms 38. The outer surface 56 is preferably continuous with the outer surfaces 44 of each of the arms 38. The inner surface 54 is preferably continuous with the inner surfaces 42 of each of the arms 38.

The generally forward-facing surface 60 is in the form of a generally U-shaped tongue surface as shown most clearly in Figures 1 and 4. In this embodiment the tip 50 is formed by a part of an edge between the U-shaped tongue surface 60 and the outer surface 56. The tip 50 of the manipulation element 10 is at a point furthest from the root portion 12 in a direction parallel to the longitudinal axis 34.

A manipulation surface 62 of the manipulation element 10 extends from the tip 50 towards the root portion 12. The manipulation surface 62 comprises the generally forward-facing surface 60 of the tip portion 52 and the second edge surfaces 48 of each of the arms 38. Preferably the generally forward-facing surface 60 of the tip portion 52 is continuous with the second edge surfaces 48 of the arms 38. The manipulation surface 62 may also include a surface of the root portion 12. In embodiments in which the manipulation surface 62 includes a surface of the root portion 12 the surface of the root portion 12 is preferably continuous with the second edge surfaces 48 of the arms 38.

The manipulation surface 62 may be planar or may be curved or partially curved. Preferably the manipulation surface 62 does not include any steps or shoulders or other abrupt changes in the surface profile. This allows an object to move or slide along the manipulation surface smoothly, as described further below. A line connecting the tip 52 to a proximal end of the manipulation surface 62 extends at a non-zero angle to the longitudinal axis 34 of the manipulation element 10. It will be appreciated that the entirety of the manipulation surface 62 may extend at a nonzero angle to the longitudinal axis 34 of the manipulation element 10 (for example in the case of a planar manipulation surface 62) or, alternatively, at least a substantial part of the manipulation surface 62 extends at a non-zero angle to the longitudinal axis 34 of the manipulation element 10 (for example in cases where the manipulation surface 62 is completely or partially curved).

The manipulation surface 62 crosses a plane containing the longitudinal axis 34. In this way the tip 52 of the manipulation element 10 is on a first side of a plane containing the longitudinal axis 34 and the proximal end of the manipulation surface 62 is on an opposite second side of the plane. In use, the manipulation surface 62 is brought into contact with an obstructing object, such as an unseated flapper in a downhole safety valve. By applying a force to the obstructing object, the obstructing object may be pushed along the manipulation surface 62 in a direction towards the root portion 12 of the manipulation element 10. The angle of the manipulation surface 62 means that, in doing so, the obstructing object may be moved to one side of a downhole passage thereby removing the obstruction.

In use the manipulation element 10 is secured to a forward end or nose portion of a downhole camera assembly. The manipulation element 10 is preferably secured to the downhole camera assembly such that a front view or forward-facing camera is disposed between the arms 38 of the manipulation element 10. As such, a part of the forward end or nose portion of the camera assembly preferably extends through the aperture 24 of the tubular attachment portion 14 and annular collar 18 and through the bore 32 of the body section 26. The forward end or nose portion of the camera assembly preferably protrudes from the aperture 30 of the body section 26 such that a front view camera or at least a lens of the front view camera is disposed in the gap 40 between the arms 38. In preferred embodiments a field of view of the front view camera does not extend rearward of the root portion 12 of the manipulation element 10. This will now be described further with reference to an embodiment of a manipulation tool 70 shown in Figures 5 to 12.

In this preferred embodiment, the manipulation tool 70 comprises a manipulation element 10 as described above. A longitudinal axis 68 of the manipulation tool 70 is parallel and coincident with the longitudinal axis 34 of the manipulation element 10.

In this embodiment the aperture 64 of the manipulation element 10 is covered by a transparent window element or cover element 86. The window element 86 is preferably semi-cylindrical or part-cylindrical in shape, having a concave internal surface and a convex external surface.

The attachment portion 14 of the manipulation element 10 is secured to a sleeve 72 of the tool 70. The external threads 16 of the attachment portion 14 are engaged with internal threads 74 at a forward end of the sleeve 72. The sleeve 72 is mounted to a connector body 76 that is configured to connect to a forward end of a tool string or other downhole assembly. A camera assembly 78 is connected to the connector body 76 and extends forward of the connector body 76 and through the root portion 12 of the manipulation element 10.

In this embodiment the camera assembly 78 comprises a camera including a wide angle lens 80, light sources 82 for illuminating a field of view of the camera, and suitable electronics 84 for controlling the camera and light sources 82 as well as, preferably, receiving and transmitting signals and data. Preferably the camera is a video camera. Preferably the camera assembly 78 is configured to transmit images captured by the camera in real-time so as to allow an operator of the manipulation tool 70 to position the tool 70 as required based on the captured images.

The arrangement of the camera assembly 78 is known in the art and will not be described in detail. The wide angle lens 80 may be an ultra wide angle lens. The wide angle lens may be fisheye lens. The lens may have an angle of view of between 60° and 118°. In other embodiments the camera assembly may not include a wide angle lens, but may include any form of lens providing the required field of view. The lens of the camera assembly may form part of a group of lenses. The lens or group of lenses preferably has a wide angle field of view.

The wide angle lens 80 is disposed in the gap 40 between the arms 38 of the manipulation element 10. In this embodiment the light sources 82 are also disposed in the gap 40. In particular, the light sources 82 are preferably disposed between the lens 80 and the forward facing surface 28 of the body section 26.

With the lens 80 disposed in the gap 40 between the arms 38 the forward facing camera has a field of view that has a centreline parallel to the longitudinal axis 68 of the manipulation tool 70. Preferably the camera and its associated lens 80 is positioned and oriented such that the centreline of the field of view is along the longitudinal axis 68 of the manipulation tool 70. The use of a wide angle or ultra wide angle lens 80 means that the field of view encompasses regions alongside the manipulation tool 70. This allows the field of view to include, for example, regions of a well casing sidewall or other objects or features that are alongside the manipulation tool 70 as the manipulation tool 70 passes through a downhole passage such as a casing or safety valve.

It will be appreciated that at least part of the arms 38 and the tip portion 52 of the manipulation element 10 are within the field of view of the camera. However, the shape and configuration of the stem portion 36 and the tip portion 52 of the manipulation element 10 are such that the centreline of the field of view of the camera is unobstructed. In this embodiment this is achieved due to the angle of the second edge surfaces 48 of the arms 38 and the curved inner surface 54 of the tip portion 52 being offset from the longitudinal axis 68.

A first part of the field of view includes a region ahead of the manipulation element 10 and beyond the tip portion 52. This first part of the field of view is bounded along one edge by the inner surface of the tip portion 52. A second part of the field of view includes a region alongside the manipulation element 10 and is bounded on opposite sides by the second edge surfaces 48 of the arms 38. It will be appreciated that the first and second parts of the field of view are continuous with each other. The first and second parts of the field of view may be bounded by an edge of the manipulation surface 62. A third part of the field of view is defined by the aperture 64 and bounded by the first edge surfaces 46 of the arms 38, the rearward-facing surface 58 of the tip portion and the forward-facing surface 28 of the body section 26. This third part of the field of view includes a region alongside the manipulation element 10 generally opposite to the region of the second part of the field of view.

This camera arrangement allows an operator of the manipulation tool 70 to view a region ahead of the tool 70 as the tool 70 is moved through a downhole passage to initially locate an obstructing object. The ability to view regions alongside the manipulation tool 70 allows an operator to accurately locate a destination location for the obstructing object after manipulation. For example, in the case of a flapper in a safety valve, an operator may locate the flapper which may be seated at a bottom of the safety valve and the operator may also locate a flapper window into which the broken flapper should be manipulated.

The flapper window, or other destination location, may be at any point around the 360° circumference of the downhole passage. Accordingly, in some embodiments it is desirable if the manipulation element 10 can be rotated about its longitudinal axis 34. The manipulation tool 70 may therefore include a motor and a suitable mechanism to enable such a rotation of the manipulation element 10 relative to the camera. Alternatively, the manipulation tool 70 may comprise a motor and a suitable mechanism to enable rotation of both a part of the camera assembly 78 and the manipulation element 10 together. For example the mechanism may enable coordinated rotation of the camera lens 80, light sources 82 and manipulation element 10. In further embodiments the manipulation tool 70 may be connectable to a tool string or other downhole assembly in such a way as to enable rotation of the complete manipulation tool 70 about its longitudinal axis 68. For simplicity it is preferable if only the manipulation element 10 rotates.

It will be understood that rotation of the manipulation of element 10 is required to align the manipulation surface 62 with the destination location. As described further below, during use of the manipulation tool 70, the obstructing object moves over the manipulation surface 62 to the destination location. Accordingly it is important that the manipulation surface 62 is suitably aligned with the destination location to allow this operation. The position of the camera’s wide angle lens 80 in the stem portion 36 of the manipulation element 10 means that an operator has a visual indication of when the manipulation surface 62 is in the correct position. This means that the operator can be confident that the manipulation element 10 has been rotated to the desired angle about the longitudinal axis 68 before the manipulation tool 70 is brought into contact with the obstructing object.

Figures 13 and 14 illustrate a further embodiment of a manipulation tool 170 including a manipulation element 110. Many of the features of the manipulation element 110 are identical to or very similar to features of the manipulation element 10 of the first embodiment and will not be described in detail in relation to this embodiment.

The manipulation element 110 includes a root portion 112 and a stem portion 136. In this embodiment the stem portion 136 is in the form of a hollow cylindrical wedge and includes a curved inner surface 188 and a curved outer surface 190. The inner surface 188 has a concave curvature and the outer surface 190 has a convex curvature.

The stem portion 136 further comprises an edge surface 192 that extends between the inner and outer surfaces 188, 190. This edge surface 192 is in the form of a generally U-shaped tongue surface 160. In this embodiment the edge surface 192 or tongue surface 160 forms a manipulation surface 162 of the manipulation element 110. A tip 150 of the stem portion 136 is formed by a part of an edge between the tongue surface 160 and the outer surface 190 at a distal end of the stem portion 136.

The curved inner surface 188 of the stem portion 136 defines a hollow 140 of the stem portion 136. The hollow 140 extends along a longitudinal axis 134 of the manipulation element 110. The manipulation tool 170 further comprises a camera assembly 178. The camera assembly 178 protrudes from an aperture 130 of the root portion 1 12 and extends into the hollow 140 of the stem portion 136. In particular, a lens 180 of the camera assembly 178 is disposed in the hollow 140 forward of the root portion 112.

The camera assembly 178 preferably includes a camera having a field of view that has a centreline parallel to a longitudinal axis 168 of the manipulation tool 170. The longitudinal axis 168 of the manipulation tool 170 is preferably parallel and coincident with the longitudinal axis 134 of the manipulation element 110. Preferably a first part of the field of view includes a region ahead of the manipulation element 110 and beyond the tip 150. This first part of the field of view is bounded along one edge by the inner surface 188 of the stem portion 136, and it will be appreciated that the curvature of the inner surface 188 and the hollow 140 provide an unobstructed view along the longitudinal axis 168. A second part of the field of view includes a region alongside the manipulation element 110 and is bounded by regions of the inner surface 188 adjacent the edge surface 192. The first and second parts of the field of view are preferably continuous with each other. The first and second parts of the field of view may be bounded by an edge of the manipulation surface 162.

It will be understood that this embodiment of the manipulation element 110 does not include an aperture 64 as described above and, as such, does not include a third part of the field of view, again as described above.

The manipulation tool 170 preferably includes a motor and a suitable mechanism to enable rotation of the manipulation element 110 about its longitudinal axis 134, as described above. This may be of particular desirability in relation to this embodiment of the manipulation element 110, as the solid form of the stem portion 136 (without the aperture 64) limits the field of view of the camera alongside the manipulation tool 170.

Referring now to Figures 15 to 17 the use of the manipulation tool 70 to manoeuvre an obstructing object in the form of a flapper into a flapper window (destination location) within a subsurface safety device will now be described. The manipulation tool 70, attached to a front end of a suitable toolstring or downhole assembly (not shown), is moved along a casing 200. An operator views images of a field of view ahead of the manipulation tool 70 in real time to locate the position of a safety valve 202 along the casing 200. It will be appreciated that the images from the camera are transmitted to the operator in real time by a suitable transmitter in the manipulation tool 70 or in the toolstring.

Once the safety valve 202 has been located the operator is able to visually confirm the presence of a broken flapper 204 or other obstructing object within the safety valve 202. The operator then locates the flapper window 206, or other destination location, into which the flapper 204 is to be manoeuvred. This may involve rotating the manipulation element 10 such that the flapper window 206 is visible in the second part of the field of view of the camera, between the arms 38 of the manipulation element 10.

Once the manipulation tool 10 has been rotated into the correct position the tip 50 of the manipulation tool 10 is then brought into contract with the flapper 204. Because the tip 50 of the manipulation tool 10 is offset from the longitudinal axis 34, applying a force to the flapper 204 in a direction substantially parallel to the longitudinal axis 34 causes the flapper 204 to rotate into contact with the forwardfacing surface 60 of the tip portion 52. Continued movement of the manipulation tool 70 in a longitudinal direction causes the flapper 204 to slide along the manipulation surface 62. In particular, the flapper 204 slides along the forward-facing surface 60 of the tip portion 52 and then along the second edge surfaces 48 of the arms 38. The profile of the manipulation surface preferably causes the flapper 204 to rotate through about 90° about an axis transverse or perpendicular to the longitudinal axis 68. As shown in Figure 17, this rotation of the flapper 204 causes the flapper 204 to locate in the flapper window 206 as the manipulation surface 62 is aligned with the flapper window 206.

The operator may then move the manipulation tool 70 so as to visually confirm that the flapper 204 is correctly housed in the flapper window 206. This may be achieved by moving the manipulation tool 70 further through the safety valve 202 and bringing the stem portion 36 or root portion 12 alongside the flapper window 204.

Although in the above embodiment the connector body 76 was configured to connect to a forward end of a tool string or other downhole assembly, in other embodiments the connector body 76, and possibly the sleeve 72, may be integral with or permanently connected to the tool string or downhole assembly.

In the above embodiment the camera assembly 78 included a plurality of light sources 82. In other embodiments the camera assembly 78 may include a single light source. Importantly, the light source is or light sources are arranged to illuminate the complete field of view of the camera so that an operator can clearly see features of interest within the field of view.

In the above embodiments the camera assembly included a single camera having a wide angle of view such that regions ahead of and alongside the manipulation element could be viewed by the same camera. In other embodiments the camera assembly may include an end view camera having a field of view including a region ahead of the manipulation element and a side view camera having a field of view including a region alongside the manipulation element.

Other modifications and variations not explicitly disclosed above may also be contemplated without departing from the scope of the invention as defined in the appended claims.