A METHOD FOR PLACING AND REMOVING PIPE FROM A FINGER RACK

Abstract

A system for placing and removing pipe from a finger rack of a drilling rig, the system comprising a pipe handling apparatus (140) and a finger rack (139) having at least one finger board (102) having at least two fingers (103 to 106) defining a slot (107 to 109) and a multiplicity of latches (114) arranged therebetween defining a space for a pipe, each latch (114) of the multiplicity of latches selectively movable between an open position and a closed position, the system further comprising at least one camera (101) having said at least one latch (114) of said multiplicity of latches in a field of view, capturing an image of said latch and sending said image to a master control computer (12′), said master computer control computer (12′) programmed with a set of instructions to analyse said image for details indicative of the latch (114) being in an open position or closed position, concluding the latch (114) to be in an open position or closed position and allowing or disallowing a pipe handling apparatus to place or remove a pipe in the finger rack (139) based on said conclusion.

Claims

1. A system for placing and removing pipe from a finger rack of a drilling rig, the system comprising: a pipe handling apparatus; a finger rack having at least one finger board, said at least one finger board having at least two fingers defining a slot and a multiplicity of latches arranged therebetween defining a space for a pipe, each latch of the multiplicity of latches selectively movable between an open position and a closed position; and at least one camera having said at least one latch of said multiplicity of latches in a field of view, wherein the at least one camera is adapted to capture an image of said at least one latch and send said image to a master control computer, said master control computer programmed with a set of instructions to analyse said image for details indicative of the at least one latch being in an open position or closed position, to conclude the at least one latch is in an open position or closed position, and to allow or disallow a pipe handling apparatus to place or remove a pipe in the finger rack based on said conclusion.

2. A system in accordance with claim 1, wherein the at least one camera is a high definition cctv camera which captures the image.

3. A system in accordance with claim 1, wherein the at least one camera is a range imaging camera to capture the image.

4. A system in accordance with claim 1, wherein the at least one camera is arranged on said pipe handling apparatus.

5. A system in accordance with claim 4, wherein the pipe handling apparatus comprises a pipe handling arm with a pipe gripping apparatus for gripping a pipe, and a base fixed to a column, the at least one camera fixed to said base.

6. A system in accordance with claim 1, wherein the at least one finger board is arranged in a derrick and the at least one camera is arranged on a part of said derrick in front of and above said finger board.

7. A system in accordance with claim 1, wherein the at least one camera is arranged at the back and above the finger board.

8. A system in accordance with claim 6, wherein the at least one camera is arranged on a track.

9. A system in accordance with claim 1, wherein said set of instructions to analyse said image for details indicative of the at least one latch being in an open position or closed position comprises analysing a contrast about said latch.

10. A system in accordance with claim 1, wherein said set of instructions further comprises defining a sub-image of an area about one latch, said area being sufficient to cover the one latch in a closed and open position.

11. A system in accordance with claim 1, wherein the pipe handling apparatus is controlled by a pipe handling control computer, programmed with a set of instructions to find a pipe in said finger board, to remove the pipe from the finger board and to convey the pipe to well centre, the master control computer being adapted to instruct said pipe handling computer to allow or disallow the pipe handling apparatus to place or remove a pipe in the finger rack based on said conclusion as to whether the at least one latch is in an open or closed position.

12. A system in accordance with claim 1, wherein the at least one camera is adapted to obtain at least one further image of the at least one latch after obtaining said image, said master control computer being adapted to analyse said at least one further image with said set of instructions to confirm or deny said conclusion.

13. A system as claimed in claim 1, wherein said master control computer comprises an algorithm to look for ellipses on a latch.

14. A system as claimed in claim 1, wherein said at least one latch comprises a marker.

15. A system as claimed in claim 14, wherein said master control computer comprises an algorithm to look for said marker on said at least one latch.

16. A system as claimed in claim 1, wherein said at least one camera is adapted to capture an image of said slot of said finger rack and said master control computer comprises an algorithm to look for a ghost pipe.

17. A system as claimed in claim 1, wherein said at least one camera is adapted to capture an image of said slot of said finger rack and said master control computer comprises an algorithm to look for an unregistered pipe.

18. A system in accordance with claim 1, wherein the pipe is one of: a joint of drill pipe; a stand of drill pipe; a section of casing; stand of drill pipe having a downhole tool therein or connected thereto, and a Bottom Hole Assembly or part thereof.

19. A method for placing and removing pipe from a finger rack of a drilling rig comprising a rig floor, a derrick, a pipe handling apparatus and a finger rack having at least one finger board, said at least one finger board having at least two fingers defining a slot and a multiplicity of latches arranged therebetween defining a space for a pipe, each latch of the multiplicity of latches selectively movable between an open position and a closed position, the drilling rig further comprising at least one camera having at least one latch of said multiplicity of latches in a field of view, the method comprising the steps of: capturing an image of said at least one latch with said at least one camera; sending said image to a master control computer programmed with a set of instructions to analyse said image for details indicative of the at least one latch being in an open position or closed position; analysing said image with said master control computer; concluding the at least one latch to be in an open position or closed position; and allowing or disallowing a pipe handling apparatus to place or remove a pipe in the finger rack based on said conclusion.

20. A drilling rig, comprising: a rig floor; a derrick; a pipe handling apparatus; at least one finger board having at least two fingers defining a slot and a multiplicity of latches arranged therebetween defining a space for a pipe, each latch of the multiplicity of latches selectively movable between an open position and a closed position; and at least one camera having at least one latch of said multiplicity of latches in a field of view, wherein said at least one camera is adapted to capture an image of said at least one latch and send said image to a master control computer, said master control computer programmed with a set of instructions to analyse said image for details indicative of the at least one latch being in an open position or closed position, to conclude the at least one latch is in an open position or closed position, and to allow or disallow said pipe handling apparatus to place or remove a pipe in the finger board based on said conclusion.

21. A system for monitoring the health of a multiplicity of latches in a finger board of a drilling rig, the system comprising: a drilling rig having a pipe handling apparatus and at least one finger board having at least two fingers defining a slot and a multiplicity of latches arranged therebetween defining a space for a pipe, each latch of the multiplicity of latches selectively movable between an open position and a closed position and a latch controller for controlling said latches between the open position and the closed position; and at least one camera having at least one latch of said multiplicity of latches in a field of view, wherein said at least one camera is adapted to capture an image of said at least one latch and send said image to a master control computer, said master control computer programmed with a set of instructions to analyse said image for details indicative of the at least one latch being in an open position or closed position, to conclude the latch is in an open position or closed position, the master control computer being adapted to receive a control information in a data packet from the latch controller, the control information data packet comprising information as whether said latch has bas been controlled to be in an open position or closed position, the master control computer being further adapted to perform a comparison of the said control information with the conclusion obtained from the image captured by the at least one camera and assessing the health of the at least one latch based on said comparison.

22. A system in accordance with claim 21, wherein the latch controller is incorporated into a pipe handling computer.

23. A system in accordance with claim 21, wherein if the assessment of the health of the at least one latch is unhealthy, the master control computer is adapted to send a message to a display indicating that the at least one latch is unhealthy.

24. A system in accordance with claim 21, wherein if the assessment of the health of the at least one latch is unhealthy, the master control computer is adapted to send a message to a repair operative.

25. A system in accordance with claim 24, wherein said master control computer has a pre-loaded memory comprising information about at least one of: said at least one latch; said finger board; and said pipe handling apparatus.

26. A system in accordance with claim 25, wherein said message includes at least one of said information, a copy of said image, or a copy of a further image captured by said at least one camera.

27. A system as claimed in claim 21, wherein the health of a multiplicity of latches is monitored during a commissioning procedure.

28. A system as claimed in claim 21, wherein the health of a multiplicity of latches is monitored during operation of the drilling rig.

Description

[0034] For a better understanding of the present invention, reference will now be made, by way of example, to the accompanying drawings, in which:

[0035] FIG. 1 is a side view of part of a drilling rig in accordance with the present invention having a rig floor;

[0036] FIG. 2 is a top plan schematic view of the rig floor shown in FIG. 1, in a first step of operation with parts removed for clarity;

[0037] FIG. 3 is a side view of the drilling rig shown in FIG. 1, in a further step of operation;

[0038] FIG. 4 is a perspective view of a second embodiment of the invention, showing a part of a finger board and camera arrangement of the invention, in a first stage of operation with a multiplicity of stands of drill pipe;

[0039] FIG. 5 is a perspective view of the finger board shown in FIG. 4 taken from the point of view of the camera in a second stage of operation with a multiplicity of stands of drill pipe;

[0040] FIG. 5A is an enlarged view of part of the finger board as shown in FIG. 5, with sub-images represented by dot-dash lines;

[0041] FIG. 6 is a side view of a latch in a finger of the finger board taken along line VI-VI of FIG. 4 in an open position with dotted lines showing a closed position;

[0042] FIGS. 7A, 7B and 7C show a side view of the finger board shown in FIG. 4 in a derrick with a pipe handling apparatus in accordance with the present invention for use on an offshore drilling rig, without stands of drill pipe therein;

[0043] FIG. 8 is a top plan schematic view of a third embodiment of an apparatus in accordance with the present invention;

[0044] FIG. 9 is a side schematic view of the apparatus shown in FIG. 8;

[0045] FIG. 10 is an enlarged front schematic view of part of the apparatus shown in FIG. 8; and

[0046] FIG. 11 is a side schematic view of the part of the apparatus shown in FIG. 10, partly in section.

[0047] Referring to FIGS. 1 to 3, there is shown part of a drilling rig, generally identified by reference numeral 1 having a rig floor 2 and a derrick 3. The rig floor 2 is supported on legs 4 on ground 5. The rig floor 2 has a well centre 6 and mouse holes 7 and 8. An iron roughneck 9 and drill pipe handler 10 are arranged adjacent the mouse holes 7 and 8. A catwalk 11 is arranged between the ground 5 and rig floor 2 adjacent the drill pipe handler 10.

[0048] A dog house 12 is arranged on one corner of the rig floor 2, which is typically a control room for the driller and/or tool pusher.

[0049] Two finger boards 13 and 14 are fixed in the derrick 3 approximately twenty-five metres above the rig floor 2. Finger board 13 has eleven fingers 15 to 25. Each finger 15 to 25 has six latches 13′ (only shown in finger 2) are arranged between adjacent fingers to provide storage for sixty stands of drill pipe 26. Similarly finger board 14 is able to store sixty stands of drill pipe 26. A camera 27 and 28 are each fixed on a carriage 29 and 30. The dolly 29 and 30 is movably arranged along horizontal track 31 and 32 along a path in front of the respective finger board 13 and 14.

[0050] A pipe handling arm is arranged in a gap 53 between fronts 51 and 52 of the finger boards 13 and 14. The pipe handling arm 50 has a pipe gripper 54, a first arm 55 pivot ally connected to the pipe gripper 54, a second arm 56 pivotally connected to the first arm 55, and a base 57 having a turntable with the second arm 56 pivotally connected thereto to allow a further degree of freedom.

[0051] In use, a first joint of drill pipe 33 is moved from a pipe supply rack or pile arranged on the ground 5 on to the catwalk 11. An pipe elevator 34 of pipe handler 10 depends from a line 35 and is placed about a box end 36 of the drill pipe 34. The line 35 is drawn in on a winch (not shown) to pull the first joint 33 up the catwalk 11 until it reaches a carriage 37 on a column 38 of the pipe handler 10. The winch (not shown) carries on drawing in the line 35, moving the carriage 37 up the column 38 until the lower pin end 39 of the first joint 33 is clear above the rig floor 2. The carriage 37 is rotated about column 38 into vertical alignment with mouse hole 8. The winch (not shown) is reversed to lower carriage 37, lowering the joint 33 into mouse hole 8. A spider (not shown) at mousehole 8 may be used to prevent the joint from falling through the rig floor 2 or a shoe (not shown) in the ground 5 could be used. The pipe elevator 34 is disconnected from the first joint 33 and returned to the position shown in FIG. 1. A second joint is moved from the pipe supply rack or pile in the same way and swung about column 38 into alignment with mouse hole 6. The iron roughneck 9 is swung about an iron roughneck column 40 and extended on an arm 41 to engage the first joint 33 and second joint 43. The iron roughneck 9 spins a pin end 44 of second joint 43 into box end 36 of the first joint 33 and then torques the connection. A third joint 45 is placed in mouse hole 7, and the connected joints 33 and 43 are lifted by elevator 34 and swung into alignment with mouse hole 7 and the pin end 39 of the first joint 33 lowered into a box end 46 of the third joint and a connection made there between with the iron roughneck 9 to form a stand 26 of three joints of drill pipe 33, 43 and 45.

[0052] The stand 26 is picked by the pipe gripper 54 of the pipe handling arm 50 and placed between adjacent fingers 15 to 25 of finger board 13 or 14, details of which will now be described.

[0053] Each Camera 27 and 28 is arranged in front of and above each finger board 13 and 14 respectively to obtain a good view of the latches in an open position in which a pipe can be inserted and removed and a closed position in which the pipe is restrained form removal from the finger board 13 and 14. Each camera 27 and 28 is arranged on a respective carriage 29 and 30 movably arranged on a track 31 and 32. Each track 31 and 32 lies perpendicular to the fingers 15 to 25 such that each camera 27 and 28 on respective carriage 29 and 30 moves along respective track 29 and 30 to obtain a field of view along each finger 15 to 25.

[0054] In use, the pipe handling arm 50 is controlled by an operator in a control room following a set of steps or by a master control computer 12′ following a set of preprogrammed steps to set-back a stand of drill pipe 26 in the finger board 13. The steps comprise the pipe handling arm 50 activated to move the pipe gripper 54 to engage the stand of drill pipe 26 located in the mouse hole 7. The pipe gripper 54 is activated to grip the stand of drill pipe 26. Rollers (not shown) in the pipe gripper 54 are activated to lift the stand of drill pipe out of the mouse hole 7 clear of the rig floor 2, if required. The pipe gripper 54 is then moved to a predetermined position in front of the finger board 13, for example in front of a slot defined by fingers 20 and 21. The master control computer automatically activates certain of the latch assemblies arranged between fingers 20 and 21 to move to an open position to allow the stand of drill pipe 110 to enter space 176. The master control computer also controls carriage 29 to move camera 27 along track 31 to a position directly in front of the slot defined by fingers 20 and 21. The camera 27 is controlled by the master control computer 12′ to capture at least one image of the latch assemblies along slot 108. A representation of the image captured by camera 27. The master control computer 12′ analyses the at least one image and determines if all of the relevant latches are in the image. This may be carried out by comparing the image with a preloaded known image. The master control computer also assesses which of the latches 13′ should be open and which should be in a closed position. The master control computer compares the images to those of open and closed preloaded images and looks for indications, such as a contrast in colour around features such as around the latch 111 when in a horizontal and vertical positions or for other features of the latch when in open and closed positions such as holes in the latch. The camera 27 may be provided with its own light source directed on the cameras field of view to improve such a contrast. Once the master control computer has established if the latch is in an open position or a closed position, the master control computer 12′ allows or disallows the the pipe handling apparatus 50 to move the stand of drill pipe 26 to enter the space provided in between fingers 20 and 21 on the pipe handling arm 50.

[0055] A second embodiment of the invention is shown in FIGS. 4 and 70 in which a camera 101 is fixed in a part of a pipe handling apparatus 140 shown in FIG. 7A above and in front of a finger board 102. Four fingers 103 to 106 lie parallel to one another defining three slots 107, 108 and 109 to receive stands of drill pipe 110. Each finger 103 is constructed from a box section steel girder having latch assemblies 111 on a ledge 112 on a first side 113 on to which a hinge plate 115 of the latch assembly 111 is fixed. The latch assembly 111 is shown in more detail in FIG. 6. A latch 114 is pinned at a first enlarged proximal end. 117 to the hinge plate 115 with a hinge pin 119 and a narrowed distal end 118 moves in a ninety degree arc about the hinge pin 119. The depth of the latches 114 is substantially constant, such that in side view the latch 114 is a rectangle. The latch 114 has a number of holes 114′ extending through the latch 114 from front to back which form a pattern. When the latch 114 is in a closed position, the distal end 118 of the latch 114 may rest on or lie adjacent to a ledge 116 of a second side 121 of the fingers 103 to 106. A double acting pneumatic ram 123 has a cylinder 124 with lower end rotatably hinged to a lug 125. The lug 125 is welded to finger 106. The ram 125 also has a piston 126 which passes through opening 130 in hinge plate 115. The piston 126 is rotatably pinned between latch lugs 127 and (not shown). The latch lugs 127 and (net shown) are welded or otherwise fixed or formed integrally with an upper face 129 of the enlarged proximal end 117 of the latch 114. Pneumatic supply nipples 133 and 134 are provided to facilitate a pneumatic connection to a supply of pneumatic fluid (not shown) through control valves (not shown). In use, when the piston 126 is extended under a supply of pneumatic fluid under pressure through nipple 134, the latch 114 moves along the arc about hinge pin 119 into the closed position. In use, when the piston 126 is retracted under a supply of pneumatic fluid under pressure through nipple 133, the latch 114 moves along the arc about hinge pin 119 into the open position.

[0056] A pipe handling apparatus 140, known as a column racker and a finger rack 139 are shown in FIGS. 7A to 7C in accordance with the present invention. The finger rack 139 comprises four finger boards 102, 154, 157, 171 in vertical alignment.

[0057] The finger board 102 is fixed to a derrick 150 at a height approximately 25 m?? above the rig floor 151. The finger 103 of finger board 102 is shown with latch assemblies 111 spaced there along at approximately 150 mm intervals. The pipe handling apparatus 140 has a rotatable column 141 rotatable about a vertical axis. A motor 142 is used to rotate the rotatable column 141. The rotatable column 141 is arranged on a track 141′ at the top of the column and a corresponding track 141″ at the bottom of the column in the rig floor 151 to allow the entire column to move along the front of the finger board 103, whilst the column 141 remains vertical. It will be noted that the track 141′ is perpendicular to the column and thus the column moves therealong into and cut of the page as shown in FIG. 7A to C. An upper pipe handling arm 143 is arranged above the finger board 102. The upper pipe handling arm 143 has a base unit 144 fixed to the rotatable column 141. An arm 145 has an upper end pivotally connected to a dolly 146 which is controllably slidable along a vertical track 147 fixed to the rotatable column 141 above the base unit 144. A lower end of arm 145 has a pipe gripper 148 pivotally connected thereto. A supporting arm 149 is pivotally connected at an upper end to a middle of the arm 145 and at the other end pivotally connected to the base 144. Upon activation by a control system (not shown), the doily moves up and down the vertical track to move the pipe gripper 148 towards and away from the rotatable column 141. The camera 101 is arranged on the base unit 144 with a field of vision between dot-dashed lines 152 and 153, looking along the length of the fingers, as shown in FIG. 5.

[0058] A second finger board 154 is fixed to the derrick 150 at a height approximately 25 m?? above rig floor 151. The second finger board is similar to the finger board 102, having fingers 155 and latches 156 which are similar or identical to the fingers 103-106 and latch assemblies 111. A third finger board 157 is fixed to the derrick 150 at a height approximately 18 m?? above rig floor 151. The third finger board 157 is similar to the finger board 102, having fingers 158 and latches 159 which are similar or identical to the fingers 103-106 and latch assemblies 111. A lower pipe handling arm 160 is generally similar to the upper pipe handling arm 143 having a base unit 161 fixed to the rotatable column 141. An arm 162 has an upper end pivotally connected to a dolly 163 which is controllably slidable along a vertical track 164 fixed to the rotatable column 141 above the base unit 161. A lower end of arm 162 has a pipe gripper 165 pivotally connected thereto. A supporting arm 166 is pivotally connected at an upper end to a middle of the arm 162 and at the other end pivotally connected to the base unit 161. Upon activation by a control system (not shown), the dolly 163 moves up and down the vertical track 164 to move the pipe gripper 165 towards and away from the rotatable column 141. Two cameras 167 and 168 are fixed to a bottom of the base unit 163. The second finger board camera 167 has a field of vision between dot-dashed lines 169 and 170. The third finger board camera 168 has a field of vision between dot-dashed lines 171′ and 172.

[0059] A fourth finger board 171 is fixed to the derrick 150 at height approximately 8 m?? above rig floor 151. The fourth finger board. 171 is similar to the finger board 102, having fingers 172 and latches 173 which are similar or identical to the fingers 103-106 and latch assemblies 111.

[0060] A fourth finger board camera 174 is fixed to the rotatable column 141. The fourth finger board camera 74 has a field of vision between dot-dashed lines 175 and 176 looking along the length of the fingers 172′.

[0061] The latch 114 is preferably red, the fingers 102 to 105 yellow and the drill pipe 110 gun metal grey such that the colours contrast.

[0062] In use, the pipe handling apparatus 140 is controlled by an operator in a control room following a set of steps or by a master control computer following a set of preprogrammed steps to place a stand of drill pipe 110 in the pipe rack 139 from a mouse hole or well centre (not shown). The steps comprise the pipe handling apparatus 140 moving along tracks 141′,141″ to a predetermined point, near the mousehole or well centre. The pipe handling arms 143 and 160 are activated to move the pipe grippers 148 and 165 away from the rotating column 141 to engage the stand of drill pipe 110 in the mouse hole or well centre. The pipe grippers 148 and 165 are activated to grip the stand of drill pipe. Rollers (not shown) in the pipe grippers 148 and 165 are activated to lift the stand of drill pipe out of the mouse hole clear of the rig floor 151, if required. The pipe grippers 148 and 165 are moved towards the rotating column 141 together with the stand of drill pipe. The pipe handling apparatus 140 is driven along the track 141′, 142″ to a predetermined position in front of the finger rack 139, for example in front of slot 108. The master control computer automatically activates latch assemblies 175 and corresponding latches in finger boards 154, 157 and 171 to move to an open position to allow the stand of drill pipe 110 to enter space 176. In use, the double acting pneumatic ram 123 is activated to move the latch 114 between a closed and open position. The camera 101 is controlled by the master control computer to capture at least one image of the latch assemblies along slot 108. The camera 108 is located on a base unit 144 of the pipe handling apparatus 140 and thus conveniently in line with slot 108. A representation of the image captured by camera 101 is shown in FIG. 5. Simultaneously, cameras 167, 168 and 174 are controlled by the master control computer to capture at least one image of the corresponding latches in finger boards 154, 157 and 171. The master control computer analyses the at least one image from each camera 101, 167, 168 and 174. The master control computer analyses the image and determines if all of the relevant latches are in the image. This may be carried out by comparing the image with a preloaded known image. The master control computer also assesses which of the latches should be open, which is in the present case that all latches should be in the closed position except for latch 114b. The image is broken up into sub images 177 and 178 as shown in FIG. 5A, in which the sub-images 177 and 178 are defined by dot-dash lines. The master control computer analyses the sub images 177 and 178 to look for indications which are indicative of the latch 114 of the latch assembly 175 and latch 114′ of latch assembly 176 being in an open on closed position. The master control computer looks for indications, such as a contrast in colour around features such as around the latch 111 when in a horizontal and vertical positions. A light may be provided in line with the camera 101 to improve such a contrast. Once the master control computer has established the positions of the latches 114a and 114b, the master control computer allows or disallows the pipe handling apparatus 140 to move the stand of drill pipe 110 from slot 108 by moving the pipe grippers 148 and 165 away from the rotatable column 141 on arms 145 and 162 moving the stand of drill pipe into the slot 108. In this case, latch 114b is concluded by the master computer control system to be in a closed position, when it should be in an open position. Thus the master control computer system disallows the pipe handling apparatus 140 from moving the stand of drill pipe to enter space 176.

[0063] A reverse procedure is carried out for removing a stand of drill pipe from the finger rack 139.

[0064] During the service life of the pipe rack 139, the colour of the latches 114 and the fingers 103 to 106 and the colour of the drill pipe 110 will change and become marked and have indents from collisions. Furthermore dirt and mud will obscure colour and change the outline of the latch. Thus the master control computer is programmed with an algorithm to ignore small differences and to look for dramatic differences in outline, such as the overall outline of a profile of the latch is an open position and closed position.

[0065] It should be noted that the first, second, third and fourth finger boards may have identical arrangement of fingers and latches to accommodate stands of drill pipe. However, the finger boards may have different arrangements of fingers and latches to accommodate casing, liner, downhole tools, production tubulars, risers, and other types of pipes. For example, the third and fourth finger boards may have additional fingers than the first and second finger boards, which additional fingers are spaced a wide spacings to accommodate large diameter casing and conductor pipe.

[0066] Referring to FIGS. 8 to 11, there is shown a third embodiment of the invention, comprising part of a finger board 200. The finger board. 200 comprises fingers 201 to 205 fixed at a back end to a derrick or other rig structure 250 and have open front ends defining slots 201′ to 204′. The fingers 201 to 205 are spaced to define slots 201′ to 205′ to receive casing (not shown). Each finger 201 to 205 is provided with nine latch assemblies 206, with adjacent latch assemblies 206 spaced along the length of the fingers 201 to 205 to define a space for each casing. The latch assemblies 205 are generally similar to the latch assemblies 111, save for the latch 207 which is of a different shape and size to the latch 114. The latch 207 has a different pattern of holes 207′ and the holes 207′ are of triangular shape. The latch is preferably red, the fingers 201 to 205 yellow and the casing gun metal grey such that the Colours contrast.

[0067] A camera 208 is arranged on a camera carriage 209 on a toothed track 210 behind and above the back of the fingers 201 to 205. The toothed track 210 extends the width of the finger board 200 and approximately 1 m?? above a horizontal plane defined by the top of the fingers 201 to 205. The camera is angled downwardly to obtain a field of vision indicated by the dot-dashed lines 211 and 212. The camera carriage 209 has a drive motor 213 having a toothed wheel 21 for engaging toothed track 210 to drive the camera carriage 209 therealong. A connector block 215 provides a connection between communication and power lines (not shown) and the camera 208 and drive motor 213. The drive motor 213 may be an X-proof electric motor or may be a hydraulic motor driven from a hydraulic supply hose (not shown). An image processing unit 216 for the camera 208 is also provided for collecting and storing and sending images to a master control computer (not shown). A chain type cable conveyor 217 is provided to retain cables whilst allowing the camera carriage 209 to traverse along toothed track 210.

[0068] In use, a pipe handling apparatus such as the one shown in FIG. 1 or 7A to 7C is controlled by an operator in a control room following a set of steps or by a master control computer following a set of preprogrammed steps to place a section of casing in the pipe rack from a mouse hole or well centre. When the pipe handling apparatus has the stand of casing in front of a slot such as slot 201′ of finger board 200, the master control computer automatically activates at least one or a plurality of latch assemblies 206 along finger 201 to move latches 207 to an open position to allow the stand of casing to enter. The camera carriage 209 is activated be the master control computer to move along track 210 so that the camera 208 has a field of view along finger 201. The camera 208 is controlled by the master control computer to capture at least one image of the latch assemblies along slot 201. The master control computer analyses the at least one image to determine if all of the relevant latches are in the image. This may be carried out by comparing the image with a preloaded known image. The master control computer also assesses which of the latches should be open. The image is broken up into sub images each defining an the latch assembly 206 and an area about the latch in which the latch moves. The master control computer analyses the sub images to look for indications which are indicative of the latch of the latch assembly 206 being in an open on closed position. The master control computer looks for indications, such, as a contrast in colour around features such as around the latch when in a horizontal and vertical positions. A light may be provided on camera carriage 209 to provide light of a designated frequency range in line with the camera 208 to improve such a contrast. Once the master control computer has established if the latch of latch assembly 206 is in an open position or closed position, the master control computer allows or disallows a casing being moved into the slot 201.

[0069] If a latch assembly is deemed not to be operating correctly by the master control computer, a notification is sent to the driller or to a designated person who can fix the problem when rig conditions are suitable, as set out below in more detail with respect to a negative health check result. In the meantime, the master control computer deems the slot unusable and will not allow casings or stands of drill pipe to be moved into or out of the finger rack.

[0070] The inventors observed that it is beneficial to check the health of the latches of a finger board on a regular basis. The inventors have observed that a finger, such as finger 103 to 106 when having slots 107 to 109 empty of stands of drill pipe 110 and of other pipe, should have the latches 114 health checked. The master computer system sends the pipe handling apparatus 139 to the empty finger 103 to 106 and activates one, some or all of the latches 114 to move to an open position. The camera 101 captures a health check image and sends the health check image to the master control computer. The image is processed in the same way as for the confirmation procedure described above to confirm if the one, some or all of the latches are in the open position. The master control computer commands the one, some or all of the latches 114 to close. The master control computer commands the camera 101 to capture another health check image. The image is processed in the same way as for the confirmation procedure described above to confirm if the one, some or all of the latches are in the closed position. If one or more of the latches 114 is not in the correct position, a negative health check command is sent to the master control computer.

[0071] In another health check embodiment, a 3D realtime model of the latch assemblies along each finger the 3D real time model will be compared to the original 3D model of the latch assemblies along each finger and will be used to check for deviations and abnormalities as the health check.

[0072] A hierarchical computer control system such as the one disclosed in WO 2004/012040 can be used to process the negative health check result to inform the correct person to fix the problem. The problem can then be fixed at the appropriate time when the drilling rig is at a stage of operation when personnel can enter the rig floor safely. In the meantime, the master control computer disallows the slot from being used.

[0073] The camera 27, 28, 101, 167, 168, 174 may be of a high definition cctv grey scale or colour camera. Preferably provided with a distance measuring device, such as a laser so that different parts of an image are provided with a distance measurement from the camera, which facilitates differentiation between latch assemblies.

[0074] The camera 27, 28, 101, 167, 168, 174 may preferably be a range imaging cameras used to create a three dimensional representation of the Latch assemblies along the finger. The camera may use a laser reflection or sonar reflection to determine distance from the camera to obtain relative differences and thus build up a three range image.

[0075] The range imaging cameras may be a stereo triangulation type in which two spaced cameras are pointed to the same spot on the rig for determining the depth to points in the scene. The two spaced cameras may be located on the same camera carriage or pipe handling apparatus or arm.

[0076] The range imaging camera may be a sheet of light triangulation type wherein the zone is illuminated with a sheet of light which creates a reflected line as seen from the light source. From any point out of the plane of the sheet the line will typically appear as a curve, the exact shape of which depends both on the distance between the observer and the light source, and the distance between the light source and the reflected points. By observing the reflected sheet of light using a high resolution camera and knowing the positions and orientations of both camera and light source, it is possible to determine the distances between the reflected points and the light source or camera. By moving either the light source (and normally also the camera) or the scene in front of the camera, a sequence of depth profiles of the scene can be generated. These can be represented as a 2D range image.

[0077] The range imaging camera may be a structured light type, wherein the zone is flooded with a specially designed light pattern, structured light, depth can be determined using only a single image of the reflected light. The structured light can be in the form of horizontal and vertical lines, points or checker board patterns.

[0078] The range imaging camera may be a time-of-flight technique, wherein a light pulse is used to, preferably with the entire zone captured with a single light pulse, although point-by-point rotating laser beam is an option. Time-of-flight cameras capture the whole zone in three dimensions with a dedicated image sensor, and therefore have no need for moving parts. A time-of-flight laser radar with a fast gating intensified CCD camera may achieves millimetre depth resolution. With this technique a short laser pulse illuminates the zone, and the intensified CCD camera opens its high speed shutter only for a few hundred picoseconds. The 3D information is calculated from a 2D image series that was gathered with increasing delay between the laser pulse and the shutter opening.