RIG FLOOR FOR A DRILLING RIG

Abstract

A system for moving items on a rig floor (2), the system comprising a plurality of skids (30-35) and a network of rails (10) for guiding the plurality of skids, each skid of said plurality of skids for supporting an item, and each skid having rail engagement members for engaging at least one rail of said network of rails. The rig floor may form part of a drilling rig such as a drill ship (1) used in the construction of oil and gas wells.

Claims

1. A system for moving items on a rig floor, the system comprising a plurality of skids and a network of rails for guiding the plurality of skids, each skid of said plurality of skids for supporting an item, and each skid having rail engagement members for engaging at least one rail of said network of rails.

2. A system as claimed in claim 1, wherein said skid comprises a propulsion unit for propelling said skid along said network of rails.

3. A system as claimed in claim 2, wherein said propulsion unit comprises two propulsion mechanisms arranged perpendicularly to one another.

4. A system as claimed in claim 2, wherein said propulsion unit comprises a cycling foot for propelling the skid along the network of rails.

5. A system as claimed in claim 4, wherein said cycling foot comprises a grabbing mechanism which selectively grabs and releases a rail of the network of rails.

6. A system as claimed in claim 2, wherein said propulsion unit is powered hydraulically.

7. A system as claimed in claim 6, wherein said skid comprises a trailing hydraulic line for powering the propulsion unit.

8. A system as claimed in claim 7, wherein said skid comprises a reel of hydraulic hose.

9. A system as claimed in claim 6, wherein the rig floor comprises a plurality of hydraulic hook-up supply points.

10. A system as claimed in claim 9, wherein said hydraulic hose has one end provided with a connector, the skid comprising a moving means for pushing the connector into one of said hydraulic hook-up supply points.

11. A system as claimed in claim 2, further comprising a propulsion control computer for controlling the propulsion unit.

12. A system as claimed in claim 1, wherein said network of rails is arranged in a grid, forming a grid of rails.

13. A system as claimed in claim 12, wherein the network of rails comprises a pair of parallel rails on which said plurality of skids are guided.

14. A system as claimed in claim 12, wherein said grid of rails comprises intersecting warp rails and a weft rails and a gap in the warp rail and a gap in the weft rail at an intersection.

15. A system as claimed in claim 14, wherein said at least one rail engagement member comprises a shoe having a skirt portion defining a longitudinal channel and a transverse channel.

16. A system as claimed in claim 1, wherein said network of rails further comprises at least one predetermined parking spot.

17. A system as claimed in claim 16, wherein said predetermined parking spot comprises a physical means actuable upon reaching said parking spot to provide a physical indication that the skid is parked.

18. A system as claimed in claim 16, wherein said predetermined parking spot comprises the rig floor having one of a locating pin and locating hole at a predetermined parking point and at least one of the skids has the other of the locating pin and locating hole, such that in use, one of the locating pin and locating hole is moved to locate the locating pin in the locating hole.

19. A system as claimed in claim 16, further comprising a master computer control system.

20. A system as claimed in claim 19, wherein a parking sensor is provided to obtain parking location information to indicate that the skid is parked at said predetermined parking spot and relaying the parking location information to the master computer control system.

21. A system as claimed in claim 20, further comprising an ID tag in said rig floor and said parking sensor is an ID tag reader for reading said ID tag in said rig floor.

22. A system as claimed in claim 19, further comprising a memory for storing skid identifier information is relaying from said skid to said master computer control system.

23. A system as claimed in claim 19, further comprising an item sensor for identifying if the item is aboard the skid and relaying the item presence information to the master computer control system.

24. A system as claimed in claim 19, further comprising an item information sensor for reading information about the item and relaying the item information to the master computer control system.

25. A system as claimed in claim 24, further comprising an ID tag on said item and said item information sensor is an ID tag reader for reading said ID tag in said rig floor, the ID tag containing information about the item.

26. A system as claimed in claim 19, further comprising skid orientation sensor and relaying skid orientation information to the master computer control system.

27. A system as claimed in claim 19, wherein at least two of said parking location information item presence information, item information, and skid orientation information is collated by an on board information gathering computer, placed in a package and sent as an information package to said master control computer system.

28. A system as claimed in claim 27, wherein the master computer control system receives said information packages for all skids on the network of rails.

29. A system as claimed in claim 27, wherein the master computer control system is programmed with information about the layout of tools and equipment for various standard operations, and optionally displaying a list of standard operations for a driller or tool pusher to choose from.

30. A system as claimed in claim 29, wherein the master computer control system controls all of the skids using the information packages.

31. A system as claimed in claim 30, wherein the master computer control system controls movement of a predetermined selection of skids to produce and the layout of tools and equipment for carrying out an operation specified by the driller or tool pusher.

32. A system as claimed in claim 29, wherein the standard operation is taken from a list comprising: drilling; tripping; casing; completion; and workover.

33. A system as claimed in claim 1, wherein the network of rails comprises a vertically movable section of rail.

34. A system as claimed in claim 2, wherein the rig floor is located in one of: a drill ship; FPSO; offshore platform, such as SPAR platform, SWATH, sea star platform and tensioned leg platform; and land rig.

35. A method of configuring items on a rig floor, wherein a plurality of skids and a network of rails for guiding the plurality of skids is provided, each skid having rail engagement members for engaging at least one rail of said network of rails, the method comprising the steps of moving an item on a skid of said plurality of skids about at least part of the rig floor.

36. (canceled)

37. A rig floor having a plurality of skids and a network of rails for guiding the plurality of skids, each skid of said plurality of skids for supporting an item, and each skid having rail engagement members for engaging at least one rail of said network of rails.

38. A skid of the rig floor as claimed in claim 37, the skid comprising a base, a propulsion unit and a shoe for engaging a rail.

39. A skid as claimed in claim 38, further comprising a reel of hydraulic hose.

40. A skid as claimed in claim 39, wherein said reel has an automatic rewind system such that the hydraulic hose remains in tension between the reel and the hook-up point.

41. A skid as claimed in claim 40, wherein said hydraulic hose is provided with a connector and the skid is provide with means for plugging said connector into a hook-up point in the rig floor.

42. A skid as claimed in claim 38, further comprising an auxiliary hydraulic line for powering equipment located on the skid.

43. A skid as claimed in claim 38, further comprising a parking system.

44. A skid as claimed in claim 38, further comprising a pin for locating in a hole in the rig floor.

45. A skid as claimed in claim 38, further comprising two propulsion assemblies arranged perpendicularly to one another and individually actuable to selectively propel the skid in a first direction and a perpendicular second direction.

46. A skid as claimed in claim 38, comprising only one of the following: a seat formed for receiving a spider; a seat formed for receiving a BOP test stump; a crane; a pipe tail handler; a riser tail handler; an iron roughneck; a continuous circulation tool; a dog house; a handling arm for handling a diverter and a base plate for supporting a diverter; a turntable and a frame thereon for supporting a rotatable drum for reeling coiled tubing; a seat formed for receiving a rotary table.

47. A drilling rig comprising a rig floor and a dog house, wherein said dog house comprises a moveable means for moving about the rig floor.

48. A drilling rig as claimed in claim 47, wherein the skid is provided with propelling means to propel said dog house around the rig floor.

49. A drilling rig as claimed in claim 47, wherein said rig floor is provided with a network of rails, and said dog house is movable along said network of rails.

50. A drilling rig as claimed in claim 49, wherein the dog house has a parking system.

Description

[0044] For a better understanding of the present invention, reference will now be made, by way of example, to the accompanying drawings, in which:

[0045] FIG. 1 is a perspective view of part of a drill ship having a rig floor in accordance with the present invention;

[0046] FIG. 2 is a perspective view of the rig floor shown in FIG. 1, in a further step of operation;

[0047] FIG. 3 is a perspective view of the rig floor shown in FIG. 1, in a yet further step of operation;

[0048] FIG. 4 is a schematic top plan view of part of the drill ship shown in FIG. 1, showing inter alia a network of rails and plurality of skids in accordance with the present invention;

[0049] FIG. 4A is a schematic top plan enlarged view of part of the rig floor showing inter alia a network of rails shown in FIG. 4;

[0050] FIG. 4B is a cross-sectional view taken along line 4B-4B of a rail shown in FIG. 4A of the network of rails of the rig floor;

[0051] FIG. 4C is a cross-sectional view of a rail of the network of rails for use on the work shop floor;

[0052] FIG. 4D is a top plan enlarged view of a warp rail intersecting a weft rail;

[0053] FIG. 5 is a side schematic view of a spider skid for moving a spider; FIG. 5A is an enlarged view of part of the spider skid shown in FIG. 5;

[0054] FIG. 6 is a top plan view of the spider skid shown in FIG. 5 with a spider thereon;

[0055] FIG. 7 is a side schematic view of the spider skid shown in FIG. 5 with a spider thereon;

[0056] FIG. 7A shows a part of the spider and spider skid shown in FIG. 5 in a first position of use on a rig floor during movement towards a parking point (with rails not shown for clarity);

[0057] FIG. 7B shows a part of the spider and spider skid shown in FIG. 5 in a parked position (with rails not shown for clarity);

[0058] FIG. 7C shows a flow diagram of a control system in accordance with the invention;

[0059] FIG. 8 is an end view of a BOP test stump skid with a BOP test stump thereon;

[0060] FIG. 9 is a top plan view of the BOP test stump skid show in FIG. 8 with the test stump thereon;

[0061] FIG. 10 is a side view of the BOP test stump skid shown in FIG. 8 with the BOP test stump thereon;

[0062] FIG. 11 is a side view of a crane skid with a crane thereon in a first step of operation;

[0063] FIG. 12 is a top plan view of the crane skid shown in FIG. 11 with the crane in the first step of operation;

[0064] FIG. 13 is a side view of the crane skid with the crane in a second step of operation;

[0065] FIG. 14 is a front view of a diverter skid with a diverter supported thereon showing a first and second step of operation;

[0066] FIG. 15 is a top plan view of the diverter skid with the diverter supported thereon;

[0067] FIG. 16 is a side view of a skid elevator of the network of rails shown in FIG. 4, with a skid elevator platform in a raised position at rig floor level;

[0068] FIG. 17 is a side view of the skid elevator of the network of rails shown in FIG. 16, with the skid elevator platform in a lowered position at workshop floor level;

[0069] FIG. 18 is a top plan view of the skid elevator platform shown in FIG. 16;

[0070] FIG. 18A shows a detail of part of the skid elevator and workshop floor;

[0071] FIG. 19 is a front view of the skid elevator shown in FIG. 16, with the skid elevator platform in a lowered position at workshop floor level;

[0072] FIG. 20 shows a schematic side view in cross-section of the drill ship shown in FIG. 4 taken along line XX-XX; and

[0073] FIG. 21 shows a schematic side view in cross-section of the drill ship shown in FIG. 4 taken along line XXI-XXI.

[0074] Referring to FIGS. 1 to 4, there is shown part of the drill ship, generally identified by reference numeral 1 having a rig floor 2 in accordance with the present invention. The perspective view is taken from aft the drill ship 1 of amidships looking towards the bow 3. The drill ship 1 has two derricks 4 and 5 arranged on a starboard side of the drill ship 1, each with a corresponding well-centre 6 and 7 located substantially along a centreline 8 of the drill ship 1. A pipe handling and make-up structure 9 is arranged on a port side of the drill ship 1. The rig floor 2 is arranged between and about the two derricks 4 and 5. The rig floor 2 surrounds the two derricks 4 and 5. A network of rails 10 is arranged in the rig floor 2. The network of rails 10 comprise a plurality of straight tracks 11 to 19. Each of tracks 11 to 19 comprises a plurality of pairs of rails, such as pairs of rails 20, 21.

[0075] A plurality of specific item skids of the invention are shown in FIGS. 1 to 3 on the network of rails 10. A pipe tail handler skid 30, a dog house skid 31, a riser handling arm skid 32, a rotary table skid 33, a coiled tubing skid 34 and a well intervention coiled tubing injector skid 35.

[0076] The network of rails 10 comprises track 11 to 19 in a layout which will be suitable for a rig floor on a drill ship 1. All tracks 11 to 19 may be used to route particular skids between destinations. However, each track 11 to 19 has a main use.

[0077] Tracks 11 and 12 lead around the back of the derricks 4 and 5 and past a downhole tool storage area 22 are used to move particular skids from a bow storage area 23 of the drill ship 1 to the main rig floor 2.

[0078] Track 13 is used mainly as a storage area 40 for item skids which may be used in an upcoming operation.

[0079] Track 14 is used mainly as an access route to guide skids from the storage area 40 to or close to well-centres 6 and 7. Track 14 also leads to a Christmas Tree elevator 44 located on the port side of the rig floor 2. Christmas Trees 45 are located in an area below the rig floor 2 on a Christmas Tree skid 46.

[0080] Track 15 is used mainly as an access route to guide skids from the bow storage area 23 to or close to the well-centres 6 and 7. Tracks 14 and 15 are also used for locating a dog house skid 31, which provide the driller and tool pusher good views of the well-centres 6 and 7.

[0081] Track 16 is used mainly as an access route to guide skids from the storage area 40 and the bow storage area 23 to and over the well-centres 6 and 7. Well-centres 6 and 7 are located within a pair of rails 24 and 25 which make up Track 16. Such item skids which will be required at well-centre comprise: spider skid 37, diverter skid 38, BOP test stump skid 39, a Continuous Circulation System skid (not shown) and a rotary table skid 33.

[0082] Track 17 is used mainly as an access route to get specific item skids close to the well-centres 6 and 7, wherein the specific item skids will generally remain on the skids on Track 17 while the item is operated, such as: a pipe tail handler skid 30; an iron roughneck skid (not shown); a casing tong skid (not shown); a crane skid 36 (shown in FIGS. 11 to 13).

[0083] Track 18 and 19 are used to route the item skids to a skid elevator 41. The skid elevator 41 lifts and lowers item skids between the rig floor 2 and a workshop floor 42. Items and item skids to be repaired and maintained will be moved along the tracks 18 and 19 to the skid elevator 41 and lowered to the workshop level which has its own network of rails 43 to move the item skids to an area of the workshop floor 42 suitable for repairing and maintaining that particular item skid.

[0084] A detail 50 of the network of rails 10 is shown in FIG. 4A. There is shown a warp track 51 intersecting a weft track 52. The warp and weft track 51 and 52 each comprise a pair of parallel rails 53, 54 and 55, 56. A cross-section of the rail 53 is shown in FIG. 4B. The rail 52 to 56 has a weight bearing body 57, curved shoulders 58 and a top 59 extending over the shoulders 58. The pairs of parallel rails 53, 54 and 55, 56 are spaced optionally 3.2 m apart between centre lines of the rails. Where the pair of parallel rails 53, 54 and 55, 56 intersect, the tops 59 of the rails stop short of touching one another, leaving a gap of approximately 75 mm therebetween which is sufficient to allow a shoe 60 (see FIG. 5) to slide between the warp and weft tracks 51 and 52. An island rail top 61 is provided to give support to the shoe 60 when a skid is crossing the intersection. Width rail tops 62, 65 and 63, 64 are provided between the parallel rails of the warp and weft track 51, 52 respectively.

[0085] FIG. 4C shows a cross-section of a rail used on the workshop floor 42, which has a slightly lower profile.

[0086] FIG. 5 shows one type of item skid, a spider skid 37. The spider skid 37 comprises a square base plate 66 having sides approximately 3.4 m in length, with a circular opening 67 therein and a depression 68 about the circular opening 67 sized to fit a spider 69. The square base plate 66 has a shoe 60 at each corner, such that the distance between shoe centres is 3.2 m. A stub leg 70 is arranged between each corner of the square base plate 66 and the shoe 60. The shoe comprises a slider 71 having a top plate 72 sized to sit on top of the rail top 59, a skirt portion 73 to fit over sides of the rail top 59 and a hook portions 74 for fitting under the rail top 59 and above the shoulders 58. The top plate 72, the skirt portion 73 and the hook portion 74 define a channel 75. A corresponding perpendicular channel (not shown) is also provided in each shoe, such that the spider skid 37 can ride along track 51, rails 53, 54 run through the pair of channels 75 and when the spider skid 39 takes track 52, the rails 55, 56 run through the corresponding perpendicular channels.

[0087] The spider skid 37 is propelled along the network of rails 10 by a propulsion system 76. The propulsion system 76 comprises a first foot 77 arranged in line with one channel 75 and arranged at a first corner 79 and a second foot 78 in line with one of the corresponding perpendicular channels (not shown) at a second corner 80. The first and second feet 77, 78 have a sole plate 81 and four selectively actuatable side grippers 82. The first and second feet 77, 78 are each provided with a movement arm 83 which each has a rigid member 84 and a hydraulic ram 85. The hydraulic ram 85 is of the double acting type. The first rigid member 84 at a proximal end is welded or otherwise fixed to the respective top plates 72 of first and second foot 77, 78 and at a distal end pinned to a cylinder end 86 of hydraulic ram 85 and a piston end 87 of the hydraulic ram is pinned to the sole plate 81. An on-board control system 88 controls flow of hydraulic fluid to the propulsion system 76.

[0088] In use, flow of hydraulic fluid to the propulsion system 76 is controlled by the on-board control system 88. The propulsion system 76 can operate in a pull or push mode and in a first direction or a perpendicular second direction. In push mode in a first direction, the hydraulic ram 85 is initially contracted and the sole plate 81 lies on a rail, such as rail 53 with the selectively actuatable side grippers 82 in an open position in which they do not touch the sides of the rails 53 and lie in a plane above the rail 53. The on-board control system 88 sends a flow of hydraulic fluid to the selectively actuatable side grippers 82 to move to a closed position in which they move downwardly and inwardly to grip the rail 53. The on-board control system sends a further flow of hydraulic fluid to the hydraulic ram 85 to extend. The spider skid 37 is pushed along rail 53 and evenly along the track 51. The selectively actuatable side grippers 82 are then released by flow of hydraulic fluid controlled by the on-board control system 88, the hydraulic ram 85 is contracted by flow of hydraulic fluid controlled by the on-board control system 88, whereupon the sole plate 81 of the first foot 77 slides along the top of the rail 53 toward the square base plate 66. These steps are repeated to cycle the foot 77 to push the spider skid in a first direction. It should be noted that the second foot 78 is not operated in this mode of operation. When the spider skid 37 reaches an intersection, t-junction or corner, the second foot in operated to push or pull the spider skid 37 therealong. For pull mode the cycle is reversed. The spider skid can travel at a speed of between 0.3 and 3 m/min.

[0089] The spider skid 37 has a parking system 90. When the spider skid is close to a predetermined parking spot, a locating pin 89 of a locating pin mechanism 90 on an underside of the square base plate 66 is activated by master control system 105, which lowers a pin on a pin ram 89′, as shown in FIGS. 7A and 7B. The parking system 90 is located centrally along one end of the square base plate 66. The locating pin 89 is now resiliently biased downwardly against the rig floor 2 by a resilient means, such as a spring 89″. The spider skid 37 continues under its self-propulsion until the locating pin 88 passes over a locating hole 91, at which point the spring biases the locating pin 88 into the locating hole 91. The control system 88 ceases the flow of hydraulic fluid to the propulsion system 76, which stops the spider skid 37 from further movement. The four selectively actuatable side grippers 82 are actuated to grip the rail 53 to act as a hand brake. Alternatively or additionally, the parking system 90 may also act as a hand brake to inhibit the spider skid 37 from moving.

[0090] A combined hydraulic fluid supply hose and communication lines 100 are provided between the rig floor 2 and the spider skid 37. Hydraulic hook-up points 92 and communication line hook-up points 93 are provided in the rig floor 2 between the rails and approximately 2.8 metres behind each locating hole 91. The hydraulic hook-up point 92 is connected to a pressurized hydraulic fluid supply (not shown), which is a common feature of all drilling rigs and drill ships. The communication line hook-up point 93 is connected to the master control computer system 105 of the drilling rig. The spider skid 37 is also provided with an automatic hook-up system. A corresponding hook-up connector mechanism 94 is provided on an opposing end of the square base plate 66 to the parking mechanism 90, approximately 2.8 m apart. The corresponding hook-up connector mechanism 94 has connector block 99 comprising a hydraulic connector 95 and a communication line connector 96 which is arranged beneath a small self-powered ram 97. The combined hydraulic fluid supply hose and communication lines 100 are fixedly connected to a top of the connector block 99. The combined hydraulic fluid supply hose and communication lines 100 is wound around a self-powered reel 101 which has a rewind mechanism (not shown), which may simply by a spring, such that when the combined hydraulic fluid supply hose and communication lines 100 is uncoiled, the spring is energised. The reel 101 is mounted on a mounting structure 102. The combined hydraulic fluid supply hose and communication lines 100 is between five and thirty metres long and most optionally between ten and twenty metres long.

[0091] In use, when the spider skid 37 is parked, the self-powered rewind reel 101 is activated to reel in the combined hydraulic fluid supply hose and communication lines 100 until the connector block 99 returns to the position shown in FIGS. 5 and 7. The small self-powered ram 97 is then activated to extend. An optional cover 103 over hook-up points 92 and 93 may be provided, which automatically opens upon the locating pin 89 inserting into locating hole 91. The small self-powered ram 97 pushes the connector block 99 on to hook-up points 92 and 93, providing the spider skid with a pressurized flow of hydraulic fluid and communication channels between the spider skid 37 and a master control computer system 105 on the drill ship 1.

[0092] The pin ram 89″ is retracted to retract pin 89 from engagement with the locating hole 91 and from contact with the rig floor 2, when the spider skid 37 begins to move.

[0093] A manual control interface 115 is provided on an arm 116 movably pinned to the square base plate 66. The manual control interface 115 may be used in place of being controlled from the master control computer system 105.

[0094] Before the spider is needed a command is sent to operatives in the workshop to prepare the spider skid 37. The spider 69 is placed on the spider skid 37 in the workshop 42. The spider skid 37 will travel up on the skid elevator 41 along tracks 13 and parked in the buffer storage area 40.

[0095] Referring to FIG. 7C, an information package is collated by an on-board information gathering computer 206. A parking RFID tag reader 200 arranged on the underside of base plate 66 adjacent the parking mechanism 90. The RFID tag reader is activated by the on-board information gathering computer 206 to read parking spot information from RFID tag 201 in the rig floor 2. The RFID tag 201 reader sends a parking spot information package, such as location and a reference number to the on-board information gathering computer 206. A spider RFID tag reader 204 is activated by the on-board information gathering computer 206 to read spider information from RFID tag 205. If there is no RFID tag 205 to read, then an on-board information package is sent to the on-board information gathering computer 206 indicating that no spider 69 is aboard the spider skid 37. A further weight sensor arranged on the base plate 66 and linked to the on-board information gathering computer 206 may be used to check this is the case. If the RFID tag reader 204 is able to read the RFID tag 205, the information relating to the spider 69 is sent to the on-board information gathering computer 206 as a spider information package. Such spider information package may include data about the type of pipe it is suitable for use with, size, and any faults it may have or have had and subsequent rectifications. An orientation information package such as orientation of the skid may also be obtained by the on-board information gathering computer 206 from an orientation sensor (not shown). A storage memory, such as RAM or EPROM (not shown) is also arranged on the spider skid containing a spider skid information package, which contains information such as a reference number and a description stating that it is a spider skid. The spider skid information package, orientation information package, spider information package, on-board information package, and parking spot information are collated into a skid information package the on-board information gathering computer 206 and sent to the master control computer system 105.

[0096] The master control system 105 is provided with a pre-programmed arrangement for setting a spider at well-centre. The master control system 105 also has skid information packages from every skid on the network of rails. The master control system 105 automatically sends the spider skid to its destination when required. For instance, the driller can press an “install drill pipe spider in first well-centre” button at a visual interface (not shown) of the master control system from the dog house skid 31. The destination will be on track 16 at one of the well-centres 6 or 7. The master control computer system 105 controls the spider skid 37 to withdraw locating pin 89 from locating hole 91 and then activate the on-board control system 88 to control the propulsion system 76, so that the spider skid 37 can move to its destination. From the storage area 40, the spider skid propels itself to track 16 to a predetermined parking spot next to well-centre. Simultaneously, a crane skid 36 (shown in FIGS. 11 to 13) is sent from buffer storage area 40 to a predetermined parking spot of track close to well-centre. The crane skid has the same self-propelling system, parking system, automatic hook-up system and automatic control system as described with reference to the spider skid 37. It should be noted that the reel of the automatic hook-up system are not shown in FIGS. 11 to 13 for clarity. The crane skid 36 is parked on track 17 at the predetermined parking spot using a parking mechanism (not shown), which is identical to the parking mechanism 90 shown and described with reference to the spider skid 37. A crane 112 on crane skid 36 is then operated from a remote location, such as from the dog house skid 31, using fly-by-wire control system (not shown) to activate hydraulic valves in the crane 112, or can be operated in automatic mode by the master control computer system 105. The computer system 105 knows the absolute location of the crane skid 36 and the spider skid 37. In automatic mode, a jib 116 is raised using ram 118 and extended using ram 119 over the spider 69 in the spider skid 37. A hook 117 is lowered on line 120 over the spider 69 and under a hook receiver of the spider (not shown). The hook 117 raised on line 120. The crane is rotated on rotating table 121 and lowered into well-centre. Alternatively, the master control system 105 controls the spider skid 37 to travel over the required well-centre 6 or 7. The spider 69 can be lifted from the spider skid 37 using a hook (not shown) depending from a top drive 106, 107 (see FIG. 20) in the derrick 4 or 5. The spider skid 37 is then moved along track 16 and then the top drive 106, 107 is lowered by a drawworks 111 via a line 108, (not shown) which passes over a crown block 109, 110 at the top of the derrick 4, 5. The spider 69 is thus lowered into the rig floor 2 at well-centre 6, 7. Hydraulic power and communication lines for the crane 112 is provided through an auxiliary line (not shown) on the crane skid 36, which branches from the combined hydraulic fluid supply hose and communication lines 100. Thus an additional hook-up is not required. The dog house skid 31 shown in FIGS. 1 to 3 comprises a cabin 47, arranged on a skid 48 incorporating the same self-propelling system, parking system, automatic hook-up system and automatic control system as herein described with reference to spider skid 37. Although, a manual hook-up system may be used, as with reference to the BOP test stump skid 39 described below. A rotating base 49 is arranged between the skid and the cabin 47 to allow the cabin 47 to rotate relative to the skid 48 to facilitate the driller and tool pusher to obtain the best view of the rig floor 2, including the well-centres 6 and 7. The dog house 31 has transparent glass sides and a transparent glass roof to facilitate the driller and tool pusher to obtain the best view of the rig floor 2.

[0097] A BOP test stump skid 39 is shown in FIGS. 8 to 10 with a BOP test stump 125 thereon. The BOP test stump skid 39 is generally similar to the spider skid 37 described above, save for the following differences. A base plate 126 is formed to support the BOP test stump 125. A reel 127 for a combined hydraulic fluid supply hose and communication lines 129 is provided with a guard 128 to circum a top portion of the reel 127. The reel is provided with an automatic rewind mechanism, as with reel 101. However, a rig hand manually plugs and unplugs the connector block 129 from hook-up point 92, 93 to hook up point as the skid progresses along the network of rails 10. Feet of the propulsion system are not shown.

[0098] A diverter skid 38 is shown in FIGS. 14 and 15 having a diverter 130 thereon. The diverter skid 38 is provided with the same self-propelling system, parking system, automatic hook-up system and automatic control system described with reference to the spider skid 37, although may have the manual hook-up system described with reference to the BOP test stump skid 39. The diverter skid 38 is thus generally similar to the spider skid 37, save for the following differences. The diverter skid has a generally planar base plate 131 and a lifting arm mechanism 132. The lifting arm mechanism 132 comprises a pair of rigid kinked arms 133 and 134 approximately 6 metres long each pivotally attached at a lower end to a lug 134′ and (not shown) welded to adjacent front corners 134′ and 135 of the base plate 131. A ram 136 and 137 is pivotally arranged between lugs 138 and 139 welded to adjacent rear corners 140 and 141 of the base plate 131 and elbows 142 and 143 of the rigid kinked arms 133 and 134. A powered crown block 144 is hung from a top bar 145 linking tops of the rigid kinked arms 133 and 134. A line 146 runs between the powered crown block 144 and a small travelling block 146 having a connector 147.

[0099] In use, the master control system 105 automatically sends the diverter skid 38 to its destination when required. For instance, the driller can press an “install diverter in first well-centre” button at a visual interface (not shown) of the master control system from the dog house skid 31. The destination will be on track 16 at one of the well-centres 6 or 7. The master control computer system 105 controls the diverter skid 38 to activate the parking system to withdraw a locating pin from locating hole 91 and then activate the on-board control system to control the propulsion system, so that the diverter skid 38 can move to its destination. From the storage area 40, the diverter skid 38 propels itself to track 16 to a predetermined parking spot next to well-centre. The lifting arm mechanism 132 is initially arranged in a first position identified in ghost lines in FIG. 14, with rams 136 and 137 in a substantially upright position and with the connector 147 connected to a lifting point (not shown) on the diverter 130. The master control computer system 105: activates the powered crown block 144 to lift the diverter 130 clear of the base 131; extends hydraulic rams 136 and 137 to shift the diverter over well-centre 6; to activate the powered crown block 144 to lower the diverter 130 on to well-centre. Alternatively, the lifting arm mechanism 132 is operated from a remote location, such as from the dog house skid 31, using fly-by-wire control system (not shown) to activate hydraulic valves (not shown) in the lifting arm mechanism 132. Hydraulic power and communication lines for the lifting arm mechanism 132 is provided through an auxiliary line (not shown) on the diverter skid 38, which branches from the combined hydraulic fluid supply hose and communication lines 100. Thus an additional hook-up is not required.

[0100] Bare skids may be provided with a simple square planar base plate to move other items around the rig floor 2. Two or more bare skids can operate in unison one behind the other in order to move long or large items. The skid elevator 41 is shown in FIGS. 16 to 19.

[0101] The skid elevator 41 comprises an elevator floor 150 having a track 151 and a perpendicular track 152 for routing skids on to tracks 13 and 19 on the rig floor 2. A locating hole 165 is provided for facilitating parking a skid on the elevator floor 151. An opening 153 in the rig floor 2 is provided which is substantially the same size as the elevator floor 151, such that when the elevator floor 2 is at the rig floor 2, there is a very small gap of a few millimetres between ends of adjacent rails 154 and 155, as shown in FIG. 18A. Hand rails 156 are provided about the elevator floor 151. Hand rails 156′ are provided about the opening 153 in the rig floor 2. Hand rails 156 on sides 157 and 158 slide downwardly when the elevator floor 151 is in line with either of the rig floor 2 or the workshop floor 42, to allow skids wish to pass. The elevator floor 151 is supported by a structure 159 which is slidably arranged on a pair of vertical 160. A motor 161 drives two pairs of toothed wheels 162 along a vertical track 163. Activation of the skid elevator 41 is controlled by the master computer control system 105.

[0102] The pipe tail handler skid 30 shown in FIGS. 1 and 2, is provided with the same self-propelling system, parking system, automatic hook-up system and automatic control system described with reference to the spider skid 37, although may have the manual hook-up system described with reference to the BOP test stump skid 39. The pipe tail handler skid 30 is thus generally similar to the spider skid 37, save for the following differences. The base 167 is substantially planar with a vertical rigid column 168 on which is mounted a pipe handler arm 166 having a pipe gripper 169′. The pipe handler arm 166 and pipe gripper 169′ are hydraulically actuated and controlled from the master control computer system 105. Hydraulic power and communication lines for the pipe handling arm 166 is provided through an auxiliary line (not shown) on the pipe tail handler skid 30, which branches from the combined hydraulic fluid supply hose and communication lines 100. Thus an additional hook-up is not required.

[0103] The riser handling arm skid 32 shown in FIGS. 1 and 3, is provided with the same self-propelling system, parking system, automatic hook-up system and automatic control system described with reference to the spider skid 37, although may have the manual hook-up system described with reference to the BOP test stump skid 39. The riser handling arm skid 32 is thus generally similar to the spider skid 37, save for the following differences. The base 190 is formed in a structural X-shape lying in a horizontal plane with a planar square central portion 191, with a raised platform 192 on which rotatably mounted a horizontal extendible riser handling arm 193 having a riser guide 194. The extendible riser handling arm 193 is hydraulically actuated and controlled from the master control computer system 105. Hydraulic power and communication lines for the extendible riser handling arm 193 is provided through an auxiliary line (not shown) on the riser handling arm skid 32, which branches from the combined hydraulic fluid supply hose and communication lines 100. Thus an additional hook-up is not required.

[0104] The coiled tubing skid 34 shown in FIG. 2, is provided with the same self-propelling system, parking system, automatic hook-up system and automatic control system described with reference to the spider skid 37, although may have the manual hook-up system described with reference to the BOP test stump skid 39. The coiled tubing skid 34 is thus generally similar to the spider skid 37, save for the following differences. The base 195 is generally planar, with a drum frame 196 rotatable mounted thereon. The drum frame has a drum 197 mounted therein, with a drum having a horizontal axis. The drum frame 196 is rotatably mounted on the planar base 195, such that the drum frame 196 can rotate about a vertical axis to allow coiled tubing 198 on the drum 197 to be played out perpendicularly to the axis of the drum, no matter where the coiled tubing skid is located on the network of rails 10. The drum 197 has a drive system (not shown) to help winding and rewinding. The drive system may be hydraulically actuated and controlled from the master control computer system 105. Hydraulic power and communication lines for the drive system is provided through an auxiliary line (not shown) on the coiled tubing skid 34, which branches from the combined hydraulic fluid supply hose and communication lines 100. Thus an additional hook-up is not required.

[0105] FIGS. 20 and 21 shows parts of the drill ship 1. The drill ship 1 has large cranes 170 which are used for loading and off-loading equipment on to a dock side. They are also used for handling equipment around the rig floor 2. There is a forward hold 171 for sections of riser 172. A pipe handling and make-up structure 9 provides an area to make-up joints of drill pipe into stands 173 which are set back in a hold 174. A pipe handling arm 175 facilitates manipulation of the stands of drill pipe from the hold 174 to the well-centre 6 or 7.

[0106] The network of rails 10 comprises track 11 to 19 in a layout which will be suitable for a rig floor on a dual derrick drill ship. A layout for other types of rigs such as a single derrick drill ship will be very similar although will have fewer track. A layout for an FPSO having a double derrick will be the same or very similar. A layout for offshore platform having a double derrick, SPAR platform, SWATH sea star platform and tensioned leg platform will be the same or very similar. Although, a skilled man will be able to draw up suitable modified layout for each type of rig. The network of rails may be simplified for a land rig, which generally has a much smaller rig floor.

[0107] It is envisaged that the hydraulic propulsion system could be replaced by a pneumatic system or a part hydraulic, part pneumatic system. It is also envisaged that the propulsion system could be electrically powered.

[0108] It is envisaged that other items could be conveyed and used whilst remaining on the skids of the invention, such as an iron roughneck and continuous circulation tool.