A WELLBORE DRILLING TOP DRIVE SYSTEM AND OPERATIONAL METHODS

Abstract

A top drive system for wellbore related activities involving a drilling tubulars string. The system includes a frame structure and a top drive device with one or more top drive motors, a transmission housing, a floating quill system with a hollow vertical floating quill shaft. The top drive device has a thrust bearing housing arranged below the transmission housing and suspended via said first and second vertical frame members from the top frame member. A hollow vertical outer main shaft is suspended from the thrust bearing housing and a hollow vertical inner main shaft is arranged vertically mobile within the outer main shaft. The inner main shaft is connected to the floating quill shaft and has a lower connector end that is configured to be connected to a drilling tubulars string via a threaded connection, so as to allow for transmission of the rotary torque from the one or more top drive motors via the transmission, the floating quill shaft, the inner main shaft, to the threadedly connected drilling tubular string.

Claims

1.-28. (canceled)

29. A top drive system for drilling a wellbore and other wellbore related activities involving a drilling tubulars string, said top drive system comprising: a frame structure adapted to support a load formed by a drilling tubulars string that passes along a firing line to or into a wellbore, a top drive device comprising: one or more top drive motors adapted to impart a rotary torque to the drilling tubulars string, a transmission housing accommodating a transmission to which said one or more top drive motors are connected, a floating quill system comprising a hollow vertical floating quill shaft that is vertically mobile relative to the transmission housing whilst in engagement with the transmission allowing the floating quill shaft to be driven by said one or more top drive motors, said floating quill system further comprising one or more floating quill shaft vertical displacement actuators configured to cause controlled vertical motion of the floating quill shaft, at least during a make up and/or a breaking of a threaded connection to the drill tubulars string, a thrust bearing housing arranged below the transmission housing and suspended from the frame structure, said thrust bearing housing being provided with a thrust bearing configured to support the load of the drilling tubulars string, a hollow vertical outer main shaft which is suspended from the thrust bearing housing via said thrust bearing so as to be rotational relative to said thrust bearing housing, said outer main shaft having a portion that extends below said thrust bearing housing, a hollow vertical inner main shaft which is arranged vertically mobile within the outer main shaft, wherein the inner main shaft is connected to the floating quill shaft so as to move vertically along with the floating quill shaft and so as to rotate along with the floating quill shaft when driven by the one or more top drive motors, wherein the inner main shaft has a lower connector end that is configured to be connected to the drilling tubulars string via a threaded connection so as to allow for transmission of the rotary torque from the one or more top drive motors via the transmission, the floating quill shaft, the inner main shaft, and the threaded connection to the drilling tubular string, wherein the inner main shaft, on the one hand, and the outer main shaft, on the other hand, are provided with cooperating axial load support faces, said axial load support faces being engaged in a lowered position of the assembly of the floating quill shaft and the inner main shaft relative to the outer main shaft and said axial load support faces being disengaged in a raised position of said assembly of the floating quill shaft and the inner main shaft relative to the outer main shaft, wherein the outer main shaft is provided with an elevator bails carrier that is configured to carry elevator bails.

30. The top drive system according to claim 29, wherein the elevator bails carrier is rotationally mounted relative to the outer main shaft, and wherein a coupling mechanism is provided that allows to selective engage and disengage the elevator bails carrier from rotating together with the outer main shaft.

31. The top drive system according to claim 29, wherein the elevator bails carrier is rotationally mounted on the outer main shaft, and wherein said axial load support faces are present on the elevator bails carrier and the outer main shaft respectively, and wherein a coupling mechanism that is effective between the elevator bails carrier and the main outer shaft comprises a lifting arrangement acting on the elevator bails carrier, which lifting arrangement is configured to selective lift and lower the elevator bails carrier relative to the outer main shaft.

32. The top drive system according to claim 29, wherein the top drive system further comprises a slewable leg structure having a head and one or more vertical legs depending from said head, which leg structure extends from the thrust bearing housing downwards, and wherein between the head of the leg structure on the one hand and the thrust bearing housing on the other hand a slew bearing is arranged that allows for the leg structure to be slewable about the vertical axis of the inner main shaft of the top drive device.

33. The top drive system according to claim 32, wherein a slew drive is provided between the slewable leg structure and the thrust bearing housing, wherein one or more slew drive motors are mounted on the thrust bearing housing and the head of the slewable leg structure is provided with a slew gear member extending about the vertical axis of the inner main shaft.

34. The top drive system according to claim 31, wherein the slewable leg structure is provided with said lifting arrangement, wherein the lifting arrangement comprises a lifting frame member that extends underneath the elevator bails carrier, which lifting frame member is vertically mobile secured to the one or more vertical legs of the slewable leg structure.

35. The top drive system according to claim 34, wherein the lifting frame member is secured to the slewable leg structure by means of a spring arrangement that normally urges the lifting frame member, and thereby the elevator bails carrier, into a lifted position thereof.

36. The top drive system according to claim 29, wherein a slew drive mechanism is provided between the thrust bearing housing and the elevator bails carrier, which slew drive mechanism is configured to cause a controlled slew motion of the elevator bails carrier relative to the thrust bearing housing about the vertical axis of the inner main shaft.

37. The top drive system according to claim 29, wherein a valve arrangement is secured to the lower connector end of the inner main shaft, said valve arrangement comprising one or more valves that are configured to control a fluid flow through the drilling tubular string.

38. The top drive system according to claim 32, wherein a backup clamp is mounted on the slewable leg structure.

39. The top drive system according to claim 29, wherein the transmission housing and the one or more top drive motors are placed on top of the thrust bearing housing.

40. The top drive system according to claim 29, wherein the connection between the inner main shaft and the floating quill shaft is a releasable threaded connection and wherein the transmission housing is releasably mounted on top of the thrust bearing housing allowing for removal of the transmission housing once the releasable connection between the floating quill shaft and the inner main shaft has been undone.

41. The top drive system according to claim 29, wherein the transmission comprises a main gear member having a vertical central splined bore through which the quill shaft extends, wherein a section of the quill shaft is splined, the splines of the gear member and the quill shaft meshing, and wherein the one or more top drive motors drive the main gear member.

42. The top drive system according to claim 29, wherein the one or more top drive motors are electric motors having a stator housing and a rotor, and wherein each top drive motor is provided with an operable clutch device configured to selectively connect and disconnect upon command the rotor of the motor relative to the transmission.

43. A method for drilling a wellbore, wherein use is made of a top drive system of claim 29, and wherein a drilling tubulars string is connected to the assembly of the floating quill shaft and the inner main shaft so that the one or more top drive motors impart rotary torque to the string, and wherein the assembly of the floating quill shaft and the inner main shaft is in a lowered position, whereby the cooperating axial load support faces are engaged, so that a drilling operation load path is established, wherein a load of the drilling tubular string passes via the inner main shaft, the cooperating axial load support faces, the outer main shaft, and the thrust bearing into the thrust bearing housing, and then to the frame structure.

44. A method for tripping a drilling tubulars string, wherein use is made of a top drive system of claim 29, and wherein during tripping of a drilling tubulars string use is made of an elevator that is suspended via elevator bails from the elevator bails carrier of the top drive system, and wherein an uppermost section of the drilling tubulars string is suspended from the elevator, so that a tripping operation load path is established, wherein a load of the drilling tubular string passes via the elevator, the elevator bails, the elevator bails carrier, the outer main shaft, and the thrust bearing into the thrust bearing housing, and then to the frame structure.

45. The top drive system according to claim 30, wherein the elevator bails carrier is rotationally mounted on the outer main shaft, and wherein said axial load support faces are present on the elevator bails carrier and the outer main shaft respectively, and wherein a coupling mechanism that is effective between the elevator bails carrier and the main outer shaft comprises a lifting arrangement acting on the elevator bails carrier, which lifting arrangement is configured to selective lift and lower the elevator bails carrier relative to the outer main shaft.

46. The top drive system according to claim 32, wherein the slewable leg structure is provided with said lifting arrangement, wherein the lifting arrangement comprises a lifting frame member that extends underneath the elevator bails carrier, which lifting frame member is vertically mobile secured to the one or more vertical legs of the slewable leg structure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0126] In the drawings:

[0127] FIG. 1 shows a perspective view on a section of a drilling tower provided with an embodiment of a top drive system according to the invention.

[0128] FIG. 2 shows in side view an embodiment of a top drive system according to the invention, along with a trolley rails and a crown block of a drilling tower,

[0129] FIG. 3 shows the top drive system of FIG. 2 in front view,

[0130] FIG. 4 shows the view of FIG. 3 with the elevator system removed for clarity,

[0131] FIG. 5 shows a top view of the top drive system of FIG. 2,

[0132] FIG. 6 shows a horizontal section of the top drive system of FIG. 2,

[0133] FIG. 7 shows another horizontal section of the top drive system of FIG. 2,

[0134] FIG. 8 illustrates, partly in vertical cross-section, main components of the top drive system of FIG. 2, wherein the inner main shaft is in its raised position,

[0135] FIG. 9 illustrates the main components of FIG. 8, wherein the inner main shaft is in its lowered position,

[0136] FIG. 10 illustrates the load path through the inner main shaft,

[0137] FIG. 11 illustrates the load path through the outer main shaft,

[0138] FIG. 12 shows partly in vertical cross-section a portion of the top drive system of FIG. 2,

[0139] FIG. 13 shows in a side view the slewable leg structure and the elevator mechanism of the top drive system of FIG. 2,

[0140] FIG. 14 shows schematically only the operation of the lifting arrangement of the elevator bails carrier when the vertical load thereon is below a threshold value,

[0141] FIG. 15 shows schematically only the operation of the lifting arrangement of the elevator bails carrier when the vertical load thereon is above a threshold value,

[0142] FIG. 16 shows the view of FIG. 14, wherein the third load path via the lifting arrangement for the elevator bails carrier, the slewable leg structure, the associated slew bearing, to the thrust bearing housing is illustrated,

[0143] FIG. 17 shows the view of FIG. 15, wherein the load path from the elevator bails carrier, the outer main shaft, the thrust bearing, to the thrust bearing housing is illustrated,

[0144] FIG. 18 illustrates the use of a wired drilling tubulars string during drilling operation,

[0145] FIGS. 19 and 20 illustrate the provision of an inductive coupler at the lower end of a floating quill or floating quill assembly of a top drive device and the mating thereof with the upper end of an uppermost drilling string tubular retained by an elevator.

DETAILED DESCRIPTION OF EMBODIMENTS

[0146] The invention will now be discussed with reference to the figures.

[0147] FIG. 1 illustrates a part of a wellbore drilling installation configured for drilling a wellbore and/or other wellbore related activities.

[0148] FIG. 1 shows a part of the drilling tower 1, e.g. the tower 1 being mounted on an offshore drilling vessel. The wellbore drilling installation may further comprises a drill floor having a well center through which a drilling tubulars string can pass along a firing line into the wellbore.

[0149] The installation further comprises at least one vertical trolley rail 2, here two parallel trolley rails 2 mounted on the tower 1.

[0150] A trolley 10 is provided, which trolley 10 is guided along the at least one vertical trolley rail 2.

[0151] The installation further comprises a main hoisting device, here comprising one or more winch driven cables 30 from which the trolley 10 is suspended.

[0152] In more detail the main hoisting device here comprises one or more winches (not shown here), for example active heave compensated winches, that drive one or more cables 30. The one or more cables 30 extend over a crown block assembly 32, with crown block sheaves 33, and in a multiple fall arrangement between said crown block assembly and a travelling block assembly 35 with travelling block sheaves 36. As known in the art, one or more of the travelling block sheaves 36 may be embodied to be selectively coupled to the trolley or in a non-active position to the crown block assembly.

[0153] The trolley 10 has a frame structure comprising: [0154] a top frame member 11 that is configured to be suspended from the main hoisting device, here from the travelling block sheaves 36, [0155] a first vertical frame member 12 and a second vertical frame member 13, each connected at an upper end thereof to the top frame member 11, said first and second vertical frame members 12, 13 depending from the top frame member spaced apart from one another and being adapted to support the load of a drilling tubulars string that passes along a firing line A to or into a wellbore.

[0156] In more detail the trolley has a frame structure formed by one or more rear frame members 14, here one rear frame member acting as a spine of the frame. The structure furthermore has one or more forward cantilevered frame members 15 extending forward from a top end of said one or more rear frame members 14. The top frame member 11 is embodied as a transverse horizontal top frame member supported by said one or more forward cantilevered frame members 15 at a distance forward of said one or more rear frame members 14.

[0157] The first and second frame members 12, 13 are suspended in a transverse plane that encompasses the firing line.

[0158] A thrust bearing housing is connected, preferably releasably, to lower ends of the first and second vertical frame members 12, 13.

[0159] The installation further comprises a top drive device 100.

[0160] The top drive device 100 comprises one or more, here four, top drive motors 120 that are adapted to impart rotary torque to a drilling tubulars string.

[0161] The top drive device 100 comprises a transmission housing 140 accommodating a transmission, here a gear transmission, to which said one or more top drive motors 120 are connected.

[0162] It is illustrated that the one or more top drive motors are electric motors having a stator housing and a rotor. As shown here, each top drive motor 120 has a vertical drive motor shaft connected to the rotor of the motor.

[0163] Preferably, at least one, preferably each, of the top drive motors 120 is provided with an operable clutch device configured to selectively connect and disconnect upon command the rotor of the motor relative to the transmission.

[0164] The top drive system further comprises a floating quill system which comprises a hollow vertical floating quill shaft 150 that is vertically mobile relative to the transmission housing 130 whilst in engagement with the transmission allowing the floating quill shaft 150 to be driven by said one or more top drive motors 120.

[0165] The floating quill system further comprises one or more floating quill shaft vertical displacement actuators, here two actuators 160 at diametrically opposed location relative to a top portion of the shaft 150 and connected to said shaft via a yoke 161. The actuators 160, e.g. hydraulic jacks, spindles, or the like, are configured to cause controlled vertical motion of the floating quill shaft 150, at least during make up and/or breaking of a threaded connection to the drill tubulars string.

[0166] The thrust bearing housing 170 is arranged below the transmission housing 140 and is suspended via the first and second vertical frame members 12, 13 from the top frame member 14 of the trolley 10.

[0167] The thrust bearing housing is provided with a thrust bearing 175 that is configured to support the load of a drilling tubulars string, e.g. a load of at least 500 tonnes.

[0168] The figures illustrate the provision in the top drive system of a hollow vertical outer main shaft 180 that is suspended from the thrust bearing housing 170 via the thrust bearing 175 so as to be rotational relative to the d thrust bearing housing 170. The outer main shaft 180 has a portion that extends below the thrust bearing housing 170.

[0169] The figures illustrate the provision in the top drive system of a hollow vertical inner main shaft 190 that is arranged vertically mobile within the outer main shaft 180.

[0170] The inner main shaft 190 is connected, here releasably connected via a threaded connection, to the floating quill shaft 150 so as to move vertically along with the floating quill shaft 150 and so as to rotate along with the floating quill shaft 150 when driven by the one or more top drive motors 120.

[0171] The inner main shaft has a passageway for drilling fluid that forms an extension of a passageway in the quill shaft 150.

[0172] The inner main shaft 190 has a lower connector end 192 that is configured to be connected to a drilling tubulars string via a threaded connection, so as to allow for transmission of the rotary torque from the one or more top drive motors 120 via the transmission 130, the floating quill shaft 150, the inner main shaft 190, to the threadedly connected drilling tubular string, e.g. for wellbore drilling.

[0173] The inner main shaft 190, preferably, has a vertical load handling capacity of at least 500 tonnes.

[0174] The inner main shaft 190, on the one hand, and the outer main shaft 180, on the other hand, are provided with cooperating axial load support faces 194, 184, e.g. formed by suitably shaped faces of the shafts 190, 180. Preferably, said faces 194, 184 are located in proximity of the thrust bearing 175 when engaged.

[0175] These axial load support faces 194, 184 are engaged with one another in a lowered position of the assembly of the floating quill shaft 150 (see FIG. 9) and the inner main shaft 190 relative to the outer main shaft 180. These axial load support faces 194, 184 are disengaged in a raised position (see FIG. 8), caused by actuators 160, of said assembly of the floating quill shaft 150 and the inner main shaft 190 relative to the outer main shaft 180.

[0176] The outer main shaft 180, here at a lower end thereof, is provided with an elevator bails carrier 200 that is configured to carry a pair of elevator bails 210.

[0177] As common in the art, the elevator bails 210 have their upper ends releasably mated with the carrier 200. At their lower the elevator bails 210 carry an elevator 220.

[0178] For example, as here, the bails 210 have an eye opening at both of their upper and lower ends. The carrier 200 may have opposed ears, wherein each bail 210 is placed with its eye part over an ear, e.g. as described in U.S. Pat. No. 7,735,565.

[0179] The elevator bails carrier 200 is rotationally mounted relative to the outer main shaft 180, preferably to the lower portion thereof below the transmission housing.

[0180] It will be appreciated that the bails 210 may also carry another component than an elevator 220 when desired.

[0181] A coupling mechanism is provided that allows to selective engage and disengage the elevator bails carrier 200 from rotating together with the outer main shaft 180.

[0182] Axial load support faces 202 and 182 are present on the elevator bails carrier 200 and the outer main shaft 180, here at the lower end thereof, respectively. As preferred these as annular faces 202, 182, preferably conical. For example, a ring member 185 having said face 182 is secured to the lower end of the shaft 180 (see e.g. FIG. 12).

[0183] The coupling mechanism effective between elevator bails carrier 200 and the main outer shaft 180 here comprises a lifting arrangement 300 acting on the elevator bails carrier 200, which lifting arrangement is configured to selective lift and lower the elevator bails carrier 200 relative to the outer main shaft 180. This will be discussed in more detail below.

[0184] It is illustrated that the transmission housing 140 and the one or more top drive motors 120 are placed on top of the thrust bearing housing 170.

[0185] The transmission housing 140 is releasably mounted, e.g. by bolts, on top of the thrust bearing housing 170, e.g. allowing for removal of the transmission housing once the releasable connection between the floating quill shaft 150 and the inner main shaft 190 has been undone.

[0186] It is illustrated that the transmission housing 140 is resiliently mounted on top of the thrust bearing housing 170, e.g. the resilient support 145 allowing for the transmission to remain aligned with the assembly of the quill shaft 150 and the inner main shaft 190.

[0187] A reaction torque structure 270 is arranged between the frame structure of the trolley, here rear frame member 14, and the transmission housing 140.

[0188] It is illustrated that the transmission comprises a main gear member 147 having a vertical central splined bore through which the quill shaft 150 extends, wherein a section of the quill shaft is splined, the splines of the gear member and the quill shaft meshing.

[0189] The one or more top drive motors 120 drive the main gear member 147, e.g. each top drive motor having a vertical drive motor shaft with a pinion 126 that meshes with the main gear member.

[0190] The figures further illustrate that the top drive system comprises a slewable leg structure 350 having a head 351 and one or more vertical legs 355, 356 depending from said head.

[0191] The leg structure 350 extends from the thrust bearing housing 170 downwards, here with two legs 355, 356 parallel to the main shaft arrangement, with each leg being laterally spaced from the outer main shaft 180.

[0192] Between the head 351 of the leg structure 350 on the one hand and the thrust bearing housing 170 on the other hand a slew bearing 360 is arranged that allows for the leg structure 350 to be slewable about the vertical axis of the main shaft arrangement of the top drive device.

[0193] A slew drive 370 is provided between the slewable leg structure 350 and the thrust bearing housing 170. As shown here one or more slew drive motors 371 are mounted on the thrust bearing housing 170 and the head of the slewable leg structure is provided with a slew gear member 372 extending about the vertical axis of the main shaft arrangement.

[0194] The slewable leg structure 350 is provided with the mentioned lifting arrangement 300.

[0195] The lifting arrangement comprises a lifting frame member 310 that extends underneath the elevator bails carrier 200. This lifting frame member 310 is vertically mobile secured to the one or more vertical legs of the slewable leg structure 350.

[0196] It is schematically illustrated in FIGS. 14-17 that the lifting frame member 310 is secured to the slewable leg structure 350 by means of a spring arrangement 320 that normally urges the lifting frame member 310, and thereby the elevator bails carrier 200, into a lifted position thereof wherein the faces 204, 184 are disengaged.

[0197] A valve arrangement 400 is secured to the lower connector end of the inner main shaft 190. This valve arrangement comprises one or more valves, e.g. a dual IBOP, that are configured to control fluid flow through the drilling tubular string. As known in the art, the one or more valves may the threaded to each other and to the lower end of the inner shaft, with a saver sub 402 being threaded to the lower end of the valve arrangement 400 for threaded connection to an uppermost section of a drilling tubulars string.

[0198] It is illustrated that a wrench and/or clamp device, e.g. a backup clamp 420, is mounted on the slewable leg structure 350. It is shown that the wrench and/or clamp device 420 is telescopically movable in vertical direction relative the one or more fixed lengths legs of the slewable leg structure 350. An vertical motion actuator 430 may be provided to move the device 420 up and down relative to the leg structure (illustrated in FIG. 13).

[0199] An elevator bails tilt mechanism 240 is provided, which is configured to move the elevator bails 210 between a vertical orientation to align the elevator with the firing and one or more tilted orientations, wherein the elevator is remote from the firing line (illustrated in FIGS. 2, 13).

[0200] A swivel fluid connector 155 is provided at the top end of the floating quill shaft 150, allowing for transfer of fluid, e.g. drilling mud, into the hollow quill shaft 150, which fluid then travels through the hollow inner main shaft 190 into the hollow tubular drilling string B during a wellbore related operation, e.g. during drilling.

[0201] 25. A method for drilling a wellbore, e.g. a subsea wellbore, and/or performing another wellbore related activity involving a drilling tubulars string, wherein use is made of a top drive system of any of claims 1-22 and/or a wellbore drilling installation of claim 23.

[0202] FIG. 10 illustrates a method for drilling a wellbore, e.g. a subsea wellbore, wherein use is made of the top drive system 100. Here a drilling tubulars string B is connected to the assembly of the interconnected floating quill shaft 150 and the inner main shaft 190 so that the one or more top drive motors 120 impart rotary torque to the string B.

[0203] In FIG. 10 the assembly of the floating quill shaft 150 and the inner main shaft 190 is in the lowered position (see e.g. FIG. 9 for more detail), whereby the cooperating axial load support faces 184,194 are engaged. Hereby a drilling operation load path is established, indicated by lines of grey rectangle in the figure, wherein a load, e.g. a weight, of the drilling tubular string B passes via the inner main shaft 190 (here via the intermediate valve arrangement 400), the cooperating axial load support faces 184,194, the upper section of the outer main shaft 180, and the thrust bearing 175 into the thrust bearing housing 170. From this housing 170 the load passes via the first and second vertical frame members 12, 13 to the top frame member 11 of the trolley and thereby via the sheaves 36 to the one or more cables 30 of the main hoisting device. This drilling operation load path avoids the transmission and the motors 120.

[0204] FIG. 11 illustrates a method for tripping a drilling tubulars string B of which an uppermost section is suspended from elevator 220. As is known, tripping is done to move a string B into or out of a wellbore, e.g. in view of maintenance of a bottomhole assembly fixed at the lower end of the string B, etc.

[0205] During tripping use is made of the elevator 220 that engages the uppermost end of the string B. The elevator 220 is suspended via elevator bails 210 from the elevator bails carrier 200 of the top drive system. A tripping operation load path is established, wherein a load, e.g. a weight, of the drilling tubular string B passes via the elevator 220, the elevator bails 210, the elevator bails carrier 200, the outer main shaft 180, and the thrust bearing 175 into the thrust bearing housing 170. The first and second vertical frame members 12, 13 pass the load on to the top frame member 11. Via the sheaves 36 the load is passed to the one or more cables 30 of the main hoisting device. This tripping operation load path avoids the transmission and the motors 120.

[0206] FIGS. 14-17 illustrate the functionality of the lifting arrangement 300. As explained the spring arrangement 320 normally urges the lifting frame member 310, and thereby the elevator bails carrier 200, into a lifted position thereof relative to the outer main shaft 180. Hereby the cooperating axial load support faces of the elevator bails carrier 200 and the outer main shaft 180 are disengaged when the vertical load on the elevator bails carrier is below a threshold value. This is shown in FIGS. 14, 16. For example, the threshold value is a load of 50 tonnes, e.g. within the load rating of the slew bearing 360.

[0207] When said vertical load by string B is above a threshold value the spring arrangement 320 gives way, e.g. springs 320 being compressed or extended, so that then the load support faces 182, 202 become engaged. This is shown in FIGS. 15, 17.

[0208] This arrangement effectively creates a third load path option of the top drive system 100, namely in case the lifting arrangement 300 causes disengagement of these axial load support faces 182, 202 of the elevator bails carrier and the outer main shaft. In this third load path option, as illustrated in FIG. 16, the vertical load acting on the elevator bails carrier 200, caused by the elevator system being in use, passes via the lifted carrier 200, the lifting arrangement 300, the slewable leg structure 350, the slew bearing 360 of said slewable leg structure, into the thrust bearing housing 170. A part of this load part is shown by grey rectangular block and a part in a solid thick black lines. As explained above, the load then passes via frame members 12, 13 to top member 11.

[0209] FIGS. 15, 17 show the situation wherein the load exerted on the carrier 300 is above the threshold value. Now the load passes from the carrier 200, the mating load support faces 182, 202, the outer shaft 180, the thrust bearing 175, into the housing 170. A part of this load part is shown by grey rectangular block and a part in a solid thick black lines. As explained above, the load then passes via frame members 12, 13 to top member 11.

[0210] With reference to FIGS. 18, 19, and 20 the second aspect of the invention will now be elucidated.

[0211] FIG. 18 schematically shows an upper end of an uppermost tubular 500, e.g. drill pipe, during a drilling operation. As known the uppermost tubular 500, as all tubulars in the string, has one or more induction coils 502 at either end thereof and a wire 503 interconnecting the coils at both ends. For example, as here, the coil 503 is located within the lower end of the threaded box portion of the tubular 500.

[0212] FIG. 18 illustrates that a wired drilling operation saver sub 504 is provided, having coils 505, 506 at opposite ends and wire 507 in between the coils. The saver sub 504 is threaded to the box portion of the tubular at the lower end. The upper end of the saver sub 504 is threaded to the lower end of a floating quill, or an inner main shaft 190 extending said floating quill, or any valve arrangement underneath the floating quill shaft 150. This floating structure is provided with yet another coil 510, that inductively communicates with coil 506.

[0213] During tripping the floating quill 150 is not required, mostly, to impart rotary torque to the drilling tubulars string. Therefore, it is envisaged that for tripping the functionality afforded by wired drilling tubulars string can be upheld in another manner.

[0214] FIG. 19 shows that a tripping operation inductive coupler 600 is fitted to the floating structure. This coupler 600 has a lower end that is not threaded, and is operable to be moved into and out of engagement with the coil 502 of tubular 500 without necessitating a screw motion. The coupler 600 has a coil 601 at its lower end that is in close proximity of the coil 502 when the coupler 600 is inserted into the box portion of the tubular due to operation of the actuators 160 associated with the floating structure of the top drive device. This insertion is illustrated in FIG. 20. The coupler 600 has another coil 602 at the upper end, linked by wire 603 to coil 601.