Abstract
An offshore drilling rig configured for lowering and/or raising a string of tubular equipment into a subsea borehole. The drilling rig includes a drill deck; a first hoisting system being adapted for raising or lowering a first load carrier along a vertical first hoisting axis, wherein the first hoisting system is supported by a first support structure extending upwardly relative to the drill deck; a second hoisting system being adapted for raising or lowering a second load carrier along a vertical second hoisting axis located apart from the first hoisting axis, wherein the second hoisting system is supported by a second support structure extending upwardly relative to the drill deck; and a joint operations well center on the drill deck. During joint operations, the first and second hoisting axes are preferably located apart from the joint operations well center.
Claims
1. An offshore drilling rig configured for lowering and/or raising a string of tubular equipment into a subsea borehole, the drilling rig comprising: a drill deck; a first hoisting system being adapted for raising or lowering a first load carrier along a vertical first hoisting axis, wherein the first hoisting system is supported by a first support structure extending upwardly relative to the drill deck and adapted for individual operation at a first work centre in the drill deck at said first hoisting axis; a second hoisting system being adapted for raising or lowering a second load carrier along a vertical second hoisting axis spaced apart from the first hoisting axis, wherein the second hoisting system is supported by a second support structure, that is separate from or common with said first support structure, extending upwardly relative to the drill deck and adapted for individual operation at a second work centre in the drill deck at said second hoisting axis; a joint operations well centre on the drill deck, wherein the first and second hoisting systems are configured for operating in conjunction over the joint operations well centre, wherein the first and second hoisting axes during joint operations are located apart from the joint operations well center and the positions of the first and second hoisting axes are fixed with respect to the drill deck.
2. An offshore drilling rig according to claim 1, wherein the joint operations well centre is the first well centre or the second well centre.
3. An offshore drilling rig according to claim 1, wherein the joint operations well centre is a third well centre different from the first and second well centres.
4. An offshore drilling rig according to claim 3, wherein the positions of the first, second and third well centres are fixed with respect to the drill deck.
5. An offshore drilling rig according claim 1, wherein at least one well centre is movable with respect to the drill deck.
6. An offshore drilling rig according to claim 5, wherein the movable well centre is the joint operations well centre.
7. An offshore drilling rig according to claim 1 wherein the first and second hoisting systems are arranged in a side-by-side configuration.
8. An offshore drilling rig according to claim 1, further comprising a connecting tool comprising a load bearing device adapted for suspending tubular equipment in axial alignment with a vertical tool axis of the connecting tool, wherein the first and second hoisting axes during joint operations are coupled together by means of the connection tool such that the tool axis is located spaced apart from the first and second hoisting axes and in alignment with the joint operations well centre.
9. An offshore drilling rig according to claim 8, wherein the tool axis is located between the first and second hoisting axes.
10. An offshore drilling rig according to claim 8, wherein the connecting tool has coupling points at which it is coupled to the hoisting systems, wherein first coupling points of the connecting tool are coupled to first elements of the drilling rig that are vertically moveable with respect to the drill deck by means of and/or in conjunction with the first hoisting system, wherein said vertically moveable first elements comprise one or more of a first load carrier of the first hoisting system, a first dolly that is vertically moveable attached to the first support structure, and a first top drive suspended by the first hoisting system and attached to the first support structure via the first dolly.
11. An offshore drilling rig according to claim 8, wherein second coupling points of the connecting tool are coupled to second elements of the drilling rig that are vertically moveable with respect to the drill deck by means of and/or in conjunction with the second hoisting system, wherein said vertically moveable second elements comprise one or more of a second load carrier of the second hoisting system, a second dolly that is vertically moveable attached to the second support structure, and a second top drive suspended by the second hoisting system and attached to the second support structure via the second dolly.
12. An offshore drilling rig according to claim 8, wherein the connecting tool further comprises a tubular mud handling device configured for at least filling drilling mud to the inside of the tubular equipment through a sealing attachment, wherein a principal direction of the sealing attachment is arranged in axial alignment with the tool axis.
13. An offshore drilling rig according to claim 12, wherein the sealing attachment is an axial press-fit seal applied in the direction of the tool axis.
14. An offshore drilling rig according to claim 12, wherein the tubular mud handling device is attached to the connecting tool.
15. An offshore drilling rig according to claim 14, wherein the tubular mud handling device is attached to the connecting tool by means of a gimbal mount.
16. An offshore drilling rig according to claim 15, further comprising at least one top drive suspended from one of the load carriers.
17. An offshore drilling rig according to claim 16, wherein a mud handling system of the top drive is operatively coupled to the tubular mud handling device via a flexing/flexible fluid connection.
18. An offshore drilling rig according to claim 8, wherein the connecting tool further comprises a swivel device (or is adapted to receive a swivel device) so the connecting tool allows for rotation around a vertical swivel axis of a load suspended in the load bearing device.
19. An offshore drilling rig according to claim 18, wherein the connecting tool and/or the swivel device comprises a rotary actuator for driving the rotation about the swivel axis.
20. An offshore drilling rig according to item 19, wherein the rotary actuator comprises an electrical or hydraulic motor.
21. An offshore drilling rig according to claim 18, further comprising at least one top drive suspended from one of the load carriers wherein the top drive is operatively coupled to the swivel device so as to drive the swivel rotation and/or wherein the top drive is operatively coupled to the link tilt device so as to drive the link tilt action.
22. An offshore drilling rig according to claim 8, wherein the connecting tool further comprises a link tilt device adapted for tilting the load bearing device at least about a horizontal tilt axis.
23. A method of lowering and/or raising a string of tubular equipment into a subsea borehole through a joint operations well centre in a drill deck of an offshore drilling rig according claim 1, the method comprising providing a first hoisting system for raising or lowering a first load carrier along a vertical first hoisting axis, wherein the first hoisting system is supported by a first support structure and adapted for individual operation at a first work centre in the drill deck at said first hoisting axis; providing a second hoisting system for raising or lowering a second load carrier along a vertical second hoisting axis, wherein the second hoisting system is supported by a second support structure, that is separate from or common with said first support structure, and adapted for individual operation at a second work centre in the drill deck at said second hoisting axis; wherein the first and second hoisting axes are laterally displaced from another by a hoisting axis distance and fixed relative to the drill deck; operatively coupling the first and second hoisting systems by means of a connecting tool, wherein the connecting tool comprises a load bearing device located at a vertical tool axis of the connecting tool, and wherein the tool axis is spaced apart from the first and second hoisting axes; engaging the tubular equipment by the load bearing device, and lowering/raising the tubular equipment when the tool axis is aligned with the joint operations well centre.
24. The method according to claim 23, wherein the tool axis is located between the first and second hoisting axes.
25. The method according to claim 24, wherein providing the first and second hoisting systems include positioning the first and second hoisting axes with respect to the joint operations well centre.
26. The method according to claim 23, wherein the first and second hoisting systems are operated in a side-by-side configuration.
27. The method according to claim 26, wherein the fixed distance is at least partially determined by the connecting tool.
28. The method according to claim 23, wherein the distance between the first and second hoisting axes at least during the step of lowering/raising the tubular equipment is larger than 5 m.
29. The method according to claim 23, wherein the joint operations well centre at least during the step of lowering/raising the tubular equipment is located between the first and second hoisting axes.
30. The method according to claim 29, wherein said drilling through the first well centre is through a drilling riser connected to the first well centre operably to guide return mud from the drilling process back to the drilling rig.
31. The method according to claim 23, further comprising a) drilling a section of a well into the seabed through the first well centre; b) hooking up the connecting tool; c) running a string of casing through the joint operations well centre via the first and second hoisting systems in collaboration.
32. The method according to claim 31, further comprising subsequently drilling a further section through the first or second well centre.
33. The method according to claim 31, comprising building (making up) at least part of the string of casing in the first well centre.
34. The method according to claim 33, comprising hanging off the string of casing and/or landing string in one or more of a blow-out preventer connected to the well, the top section of the riser connected to the first well centre during said drilling of the section of the well or in the rotary table of the movable well centre.
35. The method according to claim 31, comprising running the string of casing at least part of the way to the seabed in the first well centre.
36. The method according to claim 31, further comprising shifting said riser to the joint operations well centre located between the first well centre and the second work centre.
37. The method according to claim 36, wherein said shifting comprises moving the first well centre such as into alignment with the tool axis of the connecting tool whereby said first well centre acts as the joint operation well centre.
38. The method according to claim 36, wherein said shifting comprises disconnecting the riser from the first well centre, skidding the riser below the drill floor and connecting the riser to the joint well centre.
39. The method according to claim 23, wherein the distance between the first and second hoisting axes at least during the step of lowering/raising the tubular equipment is larger than 12 m.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Preferred embodiments of the invention will be described in more detail in connection with the appended drawings, which show schematically in
(2) FIG. 1 according to a first embodiment, a connecting tool with a tubular mud handling device attached thereto,
(3) FIG. 2 according to a second embodiment, an assembly comprising a connecting tool and a tubular mud handling device,
(4) FIG. 3 according to a third embodiment, a connecting tool with a tubular mud handling device directly attached to the heavy duty load bearing device,
(5) FIG. 4 according to a fourth embodiment, a connecting tool with a tubular mud handling device attached thereto by means of a gimbal,
(6) FIG. 5, 5a according to a fifth embodiment, a connecting tool with a swivel device and mud handling operatively connected to respective top drives,
(7) FIG. 6 according to a sixth embodiment, a connecting tool with a swivel device with an internal drive and mud handling operatively connected to one of the top drives,
(8) FIG. 7 according to a seventh embodiment, a connecting tool with a swivel device and a tubular mud handling device directly attached thereto
(9) FIG. 8 a perspective elevation of the connecting tool according to the seventh embodiment, and in
(10) FIG. 9 a detail of an offshore drilling rig with two hoisting systems connected for combined operation using the connecting tool according to the seventh embodiment.
(11) FIGS. 10-18 illustrate another embodiment of an offshore drilling rig, wherein FIG. 10 shows a side view of the drilling rig, FIGS. 11-14 show 3D views of parts of the drilling rig from different viewpoints, FIGS. 15-16 show horizontal cross-sectional views of the drilling rig, and FIGS. 17-18 show lateral cross sections of the drilling rig.
(12) Furthermore, the drawings show schematically in
(13) FIG. 19 a detail of an offshore drilling rig according to the embodiments shown in FIGS. 35 and/or 36 where the rig is configured in a side-by-side configuration with two hoisting systems connected for combined operation using the connecting tool according to an eighth embodiment,
(14) FIG. 20-22 shows various embodiments of a connecting tool which are particularly suitable for a long reach, such as being connected to two hoisting systems aligned with the two well centers of a dual activity rig. Here the well spacing is typically in the order of 8 meters or larger, such as 10 meters or larger, such as 12 meters or larger,
(15) FIG. 21 according to a tenth embodiment, a connecting tool with coupling points attached to the pipe handlers of first and second top drives,
(16) FIG. 22 according to a ninth embodiment, a connecting tool with coupling points attached directly to the load carriers of first and second hoisting systems and further coupling points attached to the pipe handlers of first and second top drives.
(17) FIG. 23 shows a support structure carrying two parallel vertical rails on which a dolly may travel in a vertical direction.
(18) FIG. 24 shows a support structure carrying a single vertical rail on which a dolly may travel in a vertical direction.
(19) FIG. 25 shows a support structure with two parts, each carrying a vertical rail.
(20) FIGS. 26-32 show different layouts for the angular orientation of two dolly systems a/b in a dual activity rig with respect to each other are now described with reference to their respective locations O(a), O(b) and forward directions Dx(a), Dx(b), as well as the corresponding transverse directions Dy(a), Dy(b).
(21) FIG. 33 shows schematically a layout of a dual activity rig having a first hoisting system and a dolly system with top drive associated therewith.
(22) FIG. 34 shows schematically an advantageous layout according to one embodiment of a dual activity drilling rig configured for individual operation at separate well centres.
(23) FIG. 35 illustrates another embodiment of an offshore drilling rig according to the invention showing a schematic representation of the drill deck of a side-by-side configured offshore drilling rig e.g. a drillship, semi-submersible or jack-up. The rig has two well centres (where one can optionally be another work hole) and a joint operations well centre.
(24) FIGS. 36-42 illustrate another embodiment of an offshore drilling rig, wherein FIGS. 36-37 show 3D views of parts of the drilling rig from different viewpoints, FIGS. 38-39 show horizontal cross-sectional views of the drilling rig, FIGS. 40-41 show lateral cross sections of the drilling rig, and FIG. 42 shows another 3D view of the drill floor seen from the starboard side of the drillship.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
(25) FIG. 1 shows a detail of a system for performing a heavy duty operation of lowering and/or raising a string of tubular equipment 99 into a subsea borehole, wherein the operation is to be performed through a well centre in a drill deck of an offshore drilling rig. The system uses a connecting tool 100 to connect two hoisting systems 140 with respective top drives 130 and associated pipe handling equipment 120 to perform the operation with combined lifting capacity that may exceed the safe working load rating (SWL) of the individual components 120, 130, 140. A mud handling device 110 is attached to the connecting tool 100. The mud handling device is adapted to supply drilling mud from a mud system of the drilling rig to the inside of the tubular equipment 99 through a sealing attachment 111.
(26) The connecting tool comprises a heavy duty load bearing device 101, by which the string of tubular equipment is suspended in axial alignment with a tool axis T defined by the load bearing device 101. The connecting tool further comprises, first and second bail sections 102a/b, each having a lower end 103a/b attached to the load bearing device on opposite sides of the tool axis T, and an upper end 104a/b defining respective first and second coupling points 105a/b of the connecting tool 101.
(27) The connecting tool further comprises a bracket 106 attached to both bail sections 102a/b at a location between the lower and upper ends 103a/b, 104a/b.
(28) The bracket 106 holds the mud handling device 110, which is configured for at least filling drilling mud to the inside of the tubular equipment 99 through the sealing attachment 111. A principal direction of the sealing attachment 111 is arranged in axial alignment with the tool axis T.
(29) In a preferred embodiment, the bail sections 102a/b have a first end 103a/b, a second end 104a/b, and a shaft portion connecting the first end 103a/b and the second end 104a/b, wherein the first end 103a/b has a bail eye or hook, and wherein the second end 104a/b is shaped and dimensioned as a drill pipe joint. The first end 103a/b is thereby configured for engaging e.g. a load bearing device 101, such as a heavy duty rated elevator, by means of a bail coupling in a conventional manner, whereas the second end is specially adapted for coupling to drill pipe lifting equipment, such as a conventional drill pipe elevator 121a/b. Such drill pipe elevators may be used as or be attached to a load carrier of a hoisting system, and are typically also found on pipe handling equipment of commonly used top drives as the top drives 130a/b shown in FIG. 1. Thereby, the bail sections 102a/b are specially adapted to allow for a simple attachment of the connecting tool 100 to conventional drill pipe lifting equipment. Using these modified bail sections 102a/b some embodiments of a connecting tool can thus be assembled using lifting components that are already known and have been proven to work under the severe requirements of subsea drilling.
(30) At one end, the connecting tool 100 is suspended from a first coupling point by a first hoisting system 140a operating along a vertical first hoisting axis A. At the other end, the connecting tool 100 is suspended from a second coupling point by a second hoisting system 140b operating along a vertical second hoisting axis B, wherein the tool axis T is located between the first and second hoisting axes A, B. During an operation of lowering/raising tubular equipment through a well centre, the tool axis is furthermore in vertical axial alignment with the well centre.
(31) The system is further equipped with top drives 130a/b suspended by load carriers 141a/b (here shown as yokes) of the hoisting systems 140a/b (here indicated as travelling blocks 142a/b). Associated pipe handling equipment 120a/b is arranged below the top drives 130a/b. The pipe handling equipment 120a/b associated with each of the top drives 130a/b comprises, respectively, a swivel device 125a/b that can be actuated by a swivel drive 126a/b, a link-tilt device 124a/b, and a pair of bails 122a/b, 123a/b carrying a drill pipe elevator 121a/b engaging a respective coupling point 105a/b of the connecting tool 100 in the form of the second (i.e. upper) end 104a/b of a bail section 102a/b. A first bail pair 122a, 123a defines a first bail plane comprising the first hoisting axis A, and a second bail pair 122b, 123b defines a second bail plane comprising the second hoisting axis B. In the embodiment of FIG. 1 the bail planes coincide, i.e. the first and second bail pairs 122a/b, 123a/b are all arranged in the same plane. This allows providing a combined link-tilt function by operating the link-tilt devices 124a/b in a synchronous mode—though without the possibility of swiveling the direction of the combined link-tilt function. Under heavy lifting load during a lowering/raising operation, the bail planes are vertical and coincide with the hoisting plane defined by the vertical hoisting axes A, B.
(32) Shaft portions of the first and second bail sections 102a/b are arranged to extend essentially vertically along the respective first and second hoisting axes A, B. In the embodiment shown in FIG. 1, the bracket 106 bridges the bail sections 102a/b and is on both ends fixed to a respective bail section 102a/b. Thereby, the mud handling device 110 is clamped to the bail sections in a fixed relation, wherein a principal direction of the sealing attachment 111 is aligned with the tool axis T.
(33) The top drives 130a/b may furthermore receive drilling mud from drilling mud supply lines 131a/b and supply the drilling mud to the mud handling device 110 through mud connection lines 112a/b. The mud connection lines may be of any suitable kind, e.g. flexible hoses, adapted to withstand any of the previously mentioned pressure ratings required for mud-filling during a lowering/raising operation.
(34) Referring to FIGS. 2-9 in the following, further embodiments of systems for performing a heavy duty operation of lowering and/or raising a string of tubular equipment 99 into a subsea borehole are disclosed, wherein like numbers refer to like parts. The embodiments shown illustrate that a large number of combinations of the different constructional elements and functionalities can be conceived. However, the embodiments shown are not to be construed exhaustive for this large variety of combinations.
(35) Like the system of FIG. 1, the systems shown in FIGS. 2-9 all have: a first hoisting system 140a being adapted for raising or lowering a first load carrier 141a along a vertical first hoisting a1 is A; a second hoisting system 140b being adapted for raising or lowering a second load carrier 141(b) along a vertical second hoisting axis B horizontally spaced apart from the first hoisting axis A, wherein the first and the second hoisting systems 140a/b are supported by a drilling support structure 150 (not shown in FIGS. 1-8) extending upwardly relative to a drill deck 160 (not shown in FIGS. 1-8); a connecting tool 100 comprising a load bearing device 101 adapted for suspending tubular equipment 99 in axial alignment with a tool axis T, wherein the connecting tool 100 is suspended from a first coupling point 105a by the first hoisting system 140a, and from a second coupling point 105b by the second hoisting system 140b such that the tool axis T is located between the first and second hoisting axes A, B and in vertical axial alignment with the well centre 161 (not shown in FIGS. 1-8); and a tubular mud handling device 110 configured for at least filling drilling mud to the inside of the tubular equipment 99 through a sealing attachment 111, wherein a principal direction of the sealing attachment 111 is arranged in axial alignment with the tool axis T. Note that each of the coupling points 105a/b may be suspended directly or indirectly from load carriers 141a/b of the respective hoisting systems 140a/b. In this respect, the coupling points 105a/b may be linked directly to the respective hoisting systems 140a/b or via further elements, such as intermittent top drives 130 and/or associated intermittent pipe handling equipment 120. The systems shown in FIGS. 1-9, are all equipped with top drives 130a/b.
(36) In the following, only differences in the configurations relating to functionality of the shown systems are highlighted.
(37) The system shown in FIG. 2 comprises an assembly with a connecting tool 200 connecting two hoisting systems 240a/b to operate in combination for performing an operation of lowering/raising a long string of tubular equipment 99 into/out of a deep borehole, wherein the tubular equipment 99 is suspended by a heavy duty load bearing device 201. The heavy load bearing device 201 is suspended by the first and second hoisting systems 240a/b by means of respective first and second bail sections 202a/b, which are shortened as compared to the embodiment of FIG. 1. The assembly further comprises a tubular mud handling device 210 mounted in a mounting bracket 206 between the first and second hoisting axes A/B, and suspended by the top drives 230a/b through pivoting joints 207 ensuring alignment with the tool axis T. Preferably, tensioners 208, are provided to strap the mounting bracket 206, and thus the mud handling tool 210, to the load bearing device 201. The tensioners 208 are adapted to counter or at least partially take up forces arising due to internal pressure inside the mud filling system 213, thereby reducing an axial load that may tend to separate the sealing attachment 211 between the mud handling device 210 and the tubular equipment 99. A mud supply line 213 connects the mud handling device 210 to a mud system of the drilling rig. The pivoting bracket-mount 206, 207, 208 suspending the mud handling device 210 at a location between the two top drives 230a/b allows for a compensation of accidental vertical misalignment between the first and second hoisting systems 240a/b, and provides a shortened design as compared to e.g. the embodiment of FIG. 1.
(38) FIG. 3 shows a system with a similarly shortened design where a connecting tool 300 has a heavy duty load bearing device 301, which is suspended in drill pipe elevators 321a/b in first and second hoisting systems 340a/b by means of shortened first and second bail sections 302a/b. The load bearing device 301 may engage the string of tubular equipment 99 by gripping means 309, e.g. remotely controllable power slips. In the design of this embodiment, a mud handling device 310 is attached directly to the load bearing device 301 and held in place by gripping means 306.
(39) FIG. 4 shows another system where a mud handling device 410 is attached directly to the connecting tool 400. The connecting tool 400 has again a heavy duty load bearing device 401 for suspending a string of tubular equipment in axial alignment with a tool axis T, which is located between the first and second hoisting axes A/B. The connecting tool 400 has an upper gimbal frame portion 471 in the form of bars having first and second coupling points 405a/b on either end, from which the connecting tool 400 is suspended by first and second bails 422a/b and corresponding further first and second bails 423a/b (not shown; hidden behind the bails 422a/b) of the first and second pipe handlers 420a/b in the first and second hoisting systems 440a/b. The bails 422a, 423a and the bails 422b, 423b form respective first and second bail pairs, each defining a vertical bail pair plane, which is perpendicular to the hoisting plane defined by the vertical first and second hoisting axes A/B, wherein the upper gimbal frame portion 471 of the connecting tool 400 is free to pivot about first and second pivot axes, which are defined by the first and second coupling points 405a/b in directions perpendicular to the hoisting plane. The connecting tool 400 has furthermore a lower gimbal frame portion 472 suspended from a gimbal axis 473, wherein the gimbal axis 473 is likewise perpendicular to the hoisting plane, and intersects the tool axis T. A mud handling device 410 is mounted coaxially in the lower gimbal frame portion 472, i.e. in axial alignment with the tool axis T. The mud handling device 410 can engage the tubular device in an axial direction via sealing attachment 411 operating along the tool axis T. The connecting tool 400 is furthermore equipped with a pipe handling section between the lower gimbal frame portion 472 and the heavy duty load bearing device 401. The pipe handling equipment comprises a link tilt device 474 for tilting a lower section of the connecting tool 400 comprising the heavy duty load bearing device 401, e.g. for picking up or dropping off tubular equipment 99 from an off-axis location. When the link tilt 474 is activated, the tool axis T is bent about a horizontal axis. The tubular mud handling device 410 is therefore equipped with a flexing portion at the location of the link tilt axis (not shown). The pipe handling equipment of the connecting tool 400 further comprises a swivel device 475 for rotation about a vertical swivel axis, which is coaxial with the tool axis T at the location of the swivel device 475, i.e. at a location above the link tilt axis. Note that the pipe handling equipment of the connecting tool 400 has to be SWL-rated for the heavy duty load capacity required for the combined lifting task. The load bearing device 401 may engage the string of tubular equipment 99 by gripping means 478, e.g. remotely controllable power slips, so as to engage the tubular equipment 99 for applying axial torque and to perform an axial rotation around the tool axis. The embodiment of FIG. 4 has an increased complexity, but has the advantage of comprising a high degree of integrated functionality for performing a large number of functions. The embodiment also provides compensation for accidental vertical misalignment of the first and second hoisting systems 440a/b.
(40) The system is further equipped with top drives 430a/b suspended by load carriers 441a/b (here shown as yokes) of the hoisting systems 440a/b (here indicated as travelling blocks 442a/b), Associated pipe handling equipment 420a/b is arranged below the top drives 430a/b. The pipe handling equipment 420a/b associated with each of the top drives 430a/b comprises, respectively, a swivel device 425a/b that can be actuated by a swivel drive 426a/b, and a link-tilt device 424a/b. The top drives 430a/b may furthermore receive drilling mud from drilling mud supply lines 431a/b and supply the drilling mud to a mud handling device through mud connection lines 412a/b. The mud connection lines may be of any suitable kind, e.g. flexible hoses, adapted to withstand any of the previously mentioned pressure ratings required for mud-filling during a lowering/raising operation.
(41) Referring to FIGS. 5 and 5a, a system with a comparable high level of functionality is shown. However, the system of FIGS. 5, 5a exploits the functionality of the first and second top drives 530a/b present in the system. Connecting tool 500 has a frame portion 580, a swivel device 575 with a swivel drive 576 for rotating a heavy duty load bearing device 501 around a swivel axis that is in axial alignment with the tool axis T. Frame portion 580 is directly suspended by first and second bails 522a/b, 523a/b of the pipe handlers 520a/b in the first and second hoisting systems 540a/b, As best seen in FIG. 5a, the tubular equipment 99 is held by the load bearing device 501 in axial alignment with the tool axis T. The sealing attachment 511, e.g. in the form of a press-fit seal, allows for rotation about the tool axis T. The mud handling device 510 is connected to the mud handling system of the drilling rig via the first top drive 530a, and the mechanical power input of the swivel drive 576 is via a transmission gear connected to a rotary drive of the second top drive 540b. Gripping means 578 allow for engaging the tubular equipment 99 for applying axial torque and to perform an axial rotation around the tool axis T.
(42) The system of FIG. 6 largely resembles the system of FIG. 5, but with rotated bail planes as defined by the bails 622a/b and 623a/b, and with an internal swivel motor for the swivel drive, which is supplied with power through input 677, e.g. in the form of hydraulic lines or electric lines. Gripping means 678 allow for engaging the tubular equipment 99 for applying axial torque and to perform an axial rotation around the tool axis T.
(43) FIG. 7 shows yet a further variation of a system with a connecting tool 700 having a frame portion 780, which is suspended by bails 722a/b, 723a/b, all arranged in the hoisting plane. A mud handling tool 710 is attached directly to the frame portion 780 of the connecting tool 700 in axial alignment with the tool axis T. The system also has a swivel function driven by the second top drive, and gripping means 778 allow for engaging the tubular equipment 99 for applying axial torque and to perform an axial rotation around the tool axis T.
(44) FIG. 8 shows a perspective elevation of a system corresponding to that shown in FIG. 7, only with vertical bail planes that are perpendicular to the hoisting plane.
(45) FIG. 9 shows an overview of a set-up with a system as described above. The set-up is for use on a drilling rig. A drill deck 960 has a well centre 961 with a diverter system 962 arranged below the drill deck 960. A support structure 950 extends upwardly relative to the drill deck 960. The support structure supports first and second hoisting systems 940a/b, each being adapted for lifting a respective load carrier 941a/b along a vertical hoisting axis A/B. The system further comprises top drives 930a/b suspended by the load carriers 941a/b and held by retractable vertical travelling dollies 932a/b. The top drives 930a/b are equipped with pipe handlers 920a/b. The two hoisting systems 940a/b with the installed top drives 930a/b and associated pipe handlers 920a/b are connected by connecting tool 900 so as to cooperate in a synchronous manner for lowering/raising tubular equipment 99 along a tool axis T into/out of a deep borehole as discussed above.
(46) While the embodiments of FIGS. 5-9 do not comprise a function for the compensation of accidental vertical misalignment between the first and second hoisting systems x40a/b, the systems may be modified to provide such misalignment compensation. For example, the connecting tool 600 of FIG. 6 may be modified to comprise an upper frame portion in the form of bars with coupling points arranged at either end and connected to a lower frame portion via an axis that is perpendicular to the hoisting plane in a similar manner as in FIG. 4, where the upper frame portion 471 suspends the lower frame portion 472 via axis 473.
(47) FIGS. 10-18 show an embodiment of a drilling rig, in this example a drillship having a hull 1501. In particular, FIG. 10 shows a side view of the drilling rig, FIGS. 11 and 12 show views of the drill floor seen from the starboard side of the drillship, FIGS. 13 and 14 show views of the drill floor seen from the port side of the drillship (a part of the hull of the ship is cut away in FIG. 14); FIGS. 15 and 16 show horizontal cross sections in a plane above the drill deck and a plane below the drill deck, respectively; finally, FIGS. 17 and 18 show lateral cross sections of the drill ship.
(48) The drilling rig of the present embodiment comprises a drill deck 2 formed on top of a substructure 1597. The substructure comprises a platform supported by legs. The platform defines the drill deck and spans across a moon pool 2122 formed in the hull of the drillship. The drill deck 2 comprises two holes defining well centres 3a,b. The drilling rig comprises a drilling support structure in the form of a mast 1. In the present example, the well centres are located within the footprint of the mast 1. The mast includes two mast portions, each associated with, and adjacent to, one of the well centres. The dual activity mast 1 is supported by the substructure 1597 and extends upwardly from the drill deck 2. The mast comprises two mast portions arranged in a face-to-face configuration, i.e. the respective mast portions are located along the axis connecting the well centres such that both well centres are located between the mast portions. Each mast portion supports a hoisting system, each for lowering a drill string through a respective one of the well centres 3a,b towards the seabed.
(49) Each of the two hoisting systems may be operable to lower tubulars selectively through a work centre at each of at least two horizontal positions, such as the central position (where the well centre 3a is located in the example of FIG. 12) and one of the peripheral positions (3b, 1003c). To this end, the mast 1 carries two cable crowns 5a,b, e.g. in the form of a crown sheave cluster or in the form of a crown block, being skidably arranged on the top of the mast on separate tracks. From each of the cable crowns lifting cables 7a,b are running down and connect to a corresponding top drive 9a,b which is suspended from a hook or other load carrier connected to the lifting cables. Each of the top drives is connected via a retractable dolly 10a,b to a vertical track arranged at the mast 1. The retractable dollies are each adapted so that they can position and keep the top drives in different positions above the well centres.
(50) Each hoisting system has one or more linear actuators in the form of a hydraulic cylinder 28a,b having its lowermost end fixed with respect to the drill deck and an upper travelling end with a cable sheave. At least one lifting cable has one end extending from another hydraulic cylinder arranged for compensating heave during e.g. drilling operation, and over the travelling cable sheave and further below a second cable sheave being fixed with respect to the mast, and thereafter over the cable crown. The hydraulic cylinders are displaced from the well centres along the direction connecting the well centres and positioned such that both well centres are located between the cylinders of the respective hoisting systems. As can be most easily seen on FIG. 15, the cylinders of each hoisting system are further (optionally) arranged in two groups of cylinders positioned on either side of an axis connecting the well centres so as to form a gap through which a catwalk machine 1508 or other pipe handling equipment can travel and feed tubulars to one or both of the well centres. Each cable crown 5a,b defines an axis that is parallel to the direction connecting the two groups of cylinders of one of the hoisting systems.
(51) As is most easily seen in FIG. 12, both hoisting systems may cooperate so as together to lower or raise tubulars through the same well centre, e.g. the well centre 3a, when located at a central position as illustrated in FIG. 12. To this end, a connecting tool 12 may be arranged to connect the top drives 9a,b. In this example, the connecting tool is in the form of an elevator and bail sections connected to said elevator in one end and suitable for being lifted by second elevators, each being connect to a respective top drive 9a,b via bails in the conventional manner. a stabbing and circulation device (e.g. in the form a casing fill-up and circulating system tools or flow back & circulation tools for drill pipe (CFT)) is mounted between the bail sections and further connected to a mud connection, preferably of one or both (as illustrated here) of the top drives. Thereby it is possible to connect a load to the connecting tool 12, so that it is possible to provide a lifting force by combining the lifting force of both hoisting systems lifting the connecting tool. To better support increased loads, the mast comprises diagonal beams 1578 forming an inverted V.
(52) The drilling rig further comprises a pipe storage area 1509 for storing pipes in horizontal orientation and catwalk machines 1508 or other horizontal pipe handling equipment for transporting pipes between the storage area 1509 and the well centres 3a,b. To this end, the catwalk machines are aligned with the axis defined by the two well centres.
(53) The drilling rig comprises a setback structure 1812 or similar pipe storage structure for storing stands of tubulars below the substructure 1597 and partly covered by the drill deck 2. The setback structure comprises a support framework 1890 supporting fingerboards having horizontally extending fingers between which tubulars may be stored. The setback structure is arranged so as to allow stands to be moved to/from both well centres from/to the setback. To this end, one or more column rackers 1891 or similar vertical pipe handling equipment may be arranged to move stands into and out of the setback structure 1812. The setback structure 1812 further comprises stand building equipment 1877 configured to build stands from individual pieces of pipe. The setback structure 1812 is located adjacent the moon pool 2122 laterally displaced from the axis defined by the well centres.
(54) Moreover the drilling rig comprises one or more further catwalk machines 1876 configured to feed tubulars from the pipe storage area 1509 or from other storage areas on the opposite side of the mast (towards the aft of the ship) to the stand building equipment 1877. The stand building equipment 1877 may thus receive the pipes from the catwalk machine 1876, bring them in upright orientation, and connect them to other pieces so as to form stands. To this end the stand building equipment may comprise a mousehole through which the stand may be gradually lowered while it is made up until the lowermost end of the stand is at the lowermost level of the setback area 1812, while the uppermost end of the stand is below the drill floor level. The stands may then be received by pipe rackers 1891 and placed in the setback structure 1812 for future use. To this end the pipe rackers are operable to traverse across the setback area, e.g. in the direction parallel to the direction connecting the well centres.
(55) The drilling rig comprises a number of slanted chutes 1892 each for feeding pipes from the setback area 1812 to one of the well centres. To this end the drilling rig may comprise one chute for each well centre position. Each chute 1892 receives pipes from one of the pipe rackers 1891 and feeds the pipes in a slanted upward direction through a corresponding slit 1785 in the drill floor towards a respective one of the well centres 3a,b, where they are picked up at their uppermost end by the corresponding hoisting system and lifted through the slit 1785 until they are vertically suspended above the corresponding well centre. To this end, the drilling rig further comprises pipe handling equipment 1786 operable to guide the pipes while they are being lifted through the slit 1785. The slits 1785 are elongated and point away from the axis connecting the well centres and towards the side where the setback area 1812 is positioned. To allow for the pipes to be presented in this fashion, the driller's cabin 1534 is positioned at an elevated level above the slits 1785. One or more further pipe handling devices, such as iron roughnecks 1727, may be located between neighbouring slits and underneath the driller's cabin, e.g. such that each iron roughneck may service two well centre positions.
(56) The drilling rig comprises another storage area 1515 below the drill deck 2 and configured for storing risers in a vertical orientation. The riser storage area 1515 is located adjacent the moon pool 2122, e.g. on the side of the moon pool opposite the setback structure 1812. The risers may then be moved, e.g. by means of a gantry crane 2298 and respective chutes 2294 or other suitable pipe feeding equipment through holes 1681 in the drill deck floor. The riser feeding holes 1681 may be covered by removable plates, hatches or similar covers, as illustrated in e.g. FIGS. 13 and 15. The riser feeding holes are displaced from the axis connecting the well centres.
(57) As the stands of tubulars and the risers are stored below the drill deck, and since the cat walk machines 1508 extend towards opposite sides from the well centres, and since the mast structure 1 is located on one side of the well centres, the drill deck provides a large, unobstructed deck area on the side of the well centres opposite the mast. This area provides unobstructed access to both well centres and is free of pipe handling equipment. Consequently, these areas may be used as working area, e.g. for rigging up suspendable auxiliary equipment, and/or for positioning on-deck auxiliary equipment. Moreover, at least parts of the setback structure 1812 may be covered by a platform 1788 so as to provide additional storage or working area.
(58) Turning now to FIGS. 19-22, further embodiments of the connecting tool are described. FIG. 19 shows a detail of an offshore drilling rig with a drill deck 3060. The drill deck 3060 has three work centres 3061a/b/c, aligned on a common axis wherein at least the work centre 3061c located in the middle is a well centre configured for giving access to the sea floor and equipped for drilling related operations at a subsea borehole. Preferably, also one or both of the work centres 3061a/b in the peripheral positions are well centres or are adapted to be operable as well centres, e.g. by moving the necessary equipment for performing drilling related operations in a subsea borehole into operation on tubulars to run through the well center. A support structure 3050 extends upwardly from the drill deck 3060. As laid out in FIG. 35-42 the support structure is preferably a mast behind the well centres but in principle surround the well centres as in a typical derrick. The first hoisting system 3040a operates at a vertical first hoisting axis A, and the second hoisting system 3040b operates at a vertical second hoisting axis B. The first and second hoisting axes A/B are laterally displaced from another and thus define a vertical common hoisting plane. Each of the hoisting systems 3040a/b comprises a respective load carrier 3041a/b travelling along the respective hoisting axes A/B. The load carriers 3041a/b are attached to travelling blocks 3042a/b, which via cables 3043a/b are raised or lowered by suitable means (not shown), such as traditional draw works, or cylinder hoisting systems as described above. The cables 3043a/b run over sheaves 3044a/b (in FIG. 35-42 referred to as Stationary sheaves 1433 or movable sheaves 2533 correspond to 3044a/b because the type of hoisting system in FIG. 19 could be that of FIG. 35 or 36) arranged at the top of the support structure 3050. The sheaves are oriented to rotate about an axis parallel to the vertical hoisting plane defined by the vertical hoisting axes A/B. This has the advantage that the hoisting systems 3040a/b may be operated in a side-by-side configuration, where the hoisting works may be arranged transversely displaced in a direction perpendicular to the common hoisting plane and on the same side thereof, thereby facilitating easy access on the drill deck 3060 to the areas around the work centres 3061a/b/c. Accordingly, such a side-by-side configuration allows also to place the support structure 3050 transversely displaced in a direction perpendicular to the common hoisting plane to improve accessibility of the working space around the work centres 3061a/b/c on the drill deck 3060. The load carriers 3041a/b suspend first and second top drives 3030a/b, which are further held in place (and secured against rotation) by retractable dollies (not shown) that are movable along vertical tracks on the support structure 3050. Each top drive 3030a/b includes a pipe handler 3020a/b.
(59) The hoisting systems are coupled together by means of a connecting tool 3000 to perform operations of lowering and/or raising tubular equipment 99 through the well centre 3061c, which is the joint operations well centre for the combined operations. The first hoisting system 3040a is arranged such that the first hoisting axis A is positioned at a first lateral distance a from the joint operations well centre 3061c, and the second hoisting system 3040b is arranged such that the second hoisting axis B is positioned at a second lateral distance b from the joint operations well centre 3061c. A first coupling point 3005a of the connecting tool 3000 is suspended by the first hoisting system 3040a, and a second coupling point 3005b of the connecting tool 3000 is suspended by the second hoisting system 3040b. The first and second coupling points 3005a/b are arranged on opposite ends of a stiff frame of the connecting tool 3000. The first and second hoisting axes A/B are thus kept at a fixed distance from each other, wherein the fixed distance is determined by the connecting tool 3000. The connecting tool 3000 comprises a load bearing device 3001 arranged at a tool axis T. The tool axis T is arranged between the first and second hoisting axes A/B. The load bearing device 3001 engages the tubular equipment 99, such as a string of casing or a riser string, such that a longitudinal axis of the tubular equipment 99 is aligned with the tool axis T. When the tool axis is furthermore aligned with the joint operations well centre 3061c, lowering and/or raising of the tubular equipment 99 can be performed.
(60) The coupling assembly further comprises a tubular mud handling device 3010 mounted in a mounting bracket 3006 between the first and second hoisting axes A/B, and suspended by the top drives 3030a/b through pivoting joints 3007 ensuring alignment with the tool axis T. The tubular mud handling device 3010 is configured for at least filling drilling mud to the inside of the tubular equipment 99 through a sealing attachment 3011, wherein a principal direction of the sealing attachment 3011 is arranged in axial alignment with the tool centre axis T.
(61) Prior to coupling the hoisting systems 3040a/b together, they may separately be engaged in individual operations at respective work/well centres, e.g. located in alignment with the work/well centres at the peripheral locations 3061a, 3061b, or even aligned with the work/well centre 3061c at the joint operations location. In order to reconfigure the offshore drilling rig from individual operation of the hoisting systems to joint operation, the respective individual operations (if any) are disrupted; the hoisting systems 3040a/b are arranged such that the respective hoisting axes A/B each are spaced apart from other by a hoisting axis distance and in a horizontal direction are spaced apart from the joint operations well centre 3061c by respective distances a/b on either side of the joint operations well centre 3061c, preferably such that the joint operations well centre 3061c is in the hoisting plane; and the hoisting systems are coupled together by using the connecting tool 3000. Depending on the particular set-up of the drilling rig, the reconfiguration from individual to joint operation may or may not require repositioning of the hoisting axes A/B with respect to the joint operations well centre. A set-up that does not require repositioning of the hoisting axes A/B will typically have less moveable components and may therefore be less costly to build, more reliable in operation, and the design may be more easily scaled up for increased load capacity.
(62) For example, the hoisting axes A/B as well as the three work/well centres 3061a/b/c may be fixed with respect to the drill deck 3060, wherein the first hoisting axis A is aligned with the first work/well centre 3061a, the second hoisting axis B is aligned with the second work/well centre 3061b, and wherein a third work/well centre, the joint operations well centre 3061c is located at a fixed position between the first and second work/well centres 3061a/b. However, to ensure safe and efficient individual operation of the hoisting systems at respective work centres or to ensure sufficient working space around the respective work centres, the hoisting axes A/B may be required to be spaced apart from each other at a minimum distance, such as at a hoisting axis distance of more than 5 m, such as more than 7 m, such as more than 10 m, or about 12 m. In a set-up with a minimum hoisting axis distance, the connecting tool connecting the two hoisting systems will therefore have to be dimensioned to sustain a corresponding span. Alternatively, in other set-ups, one or more of the well centres 3061a/b/c may be moveable at least in a direction parallel to the hoisting plane and/or at least one of the first and second hoisting axes A/B may moveable with respect to the well centres 3061a/b/c.
(63) FIGS. 20-22 show different embodiments of the coupling assembly, where the coupling points of the connecting tool are attached at different levels of the hoisting system 3040a/b with top drives 3030a/b and associated pipe handlers 3020a/b. In all embodiments, the coupling assembly includes a tubular mud handling device 3110, 3210, 3310 mounted in a respective mounting bracket 3106, 3206, 3306 between the first and second hoisting axes A/B, and suspended by means of joints 3207, 3307 (not visible in FIG. 20) ensuring alignment with the tool axis T. The tubular mud handling device 3110, 3210, 3310 is configured for at least filling drilling mud to the inside of the tubular equipment 99 through a sealing attachment 3111, 3211, 3311, wherein a principal direction of the sealing attachment 3111, 3211, 3311 is arranged in axial alignment with the tool centre axis T. Drilling mud may be supplied to the tubular mud handling device 3110, 3210, 3310 through a flexible/flexing supply line 3112, 3212, 3312.
(64) FIG. 20 shows an embodiment, where a connecting tool 3100 with first and second coupling points 3105a/b couples directly to the load carriers 3041a/b of the hoisting systems 3040a/b above top drives 3030a/b; FIG. 21 shows an embodiment, where a connecting tool 3200 with first and second coupling points 3205a/b couples to pipe handlers 3020a/b of the top drives 3030a/b; and FIG. 22 shows an embodiment where a connecting tool 3300 with first and second coupling points 3305a/b couples via a spreader beam 3315 to the pipe handlers 3020a/b and via tendons 3314a/b to the load carriers 3041a/b above the top drives 3030a/b.
(65) As mentioned above, in many embodiments, the rig is equipped with a top drive arranged to rotate drill strings and lower them through the first well centre, wherein the top drive is arranged to be lifted by the first hoisting system. To keep the top drive from rotating a guide-dolly is typically arranged to slide along a vertically extending rail or rails while being connected to the top drive. Different constructions of the dolly system may be conceived as illustrated schematically with reference to FIGS. 23-25.
(66) FIG. 23 shows a support structure 4050 carrying two parallel vertical rails 4034 on which a dolly 4032 may travel in a vertical direction. The dolly 4032 carries a top drive 4030. The dolly 4032 comprises a deployment mechanism 4033 that may be extended or retracted in order to bring the top drive 4030 in alignment with a well centre 4061 for performing drilling related operations. A front side of the dolly system may be defined as the side of the dolly 4032 facing towards the well centre 4061; A back side of the dolly system may be defined as the side of the dolly 4032 facing away from the well centre 4061; A position of the dolly system may be defined as the centre point O of the ensemble of vertical rails; A forward direction Dx of the dolly system may be defined as the direction from the centre point O towards the top drive 4030 and the well centre 4061; A transverse direction Dy may be defined as the horizontal direction perpendicular to the forward direction Dx.
(67) FIG. 24 shows a support structure 4150 carrying a single vertical rail 4134 on which a dolly 4132 may travel in a vertical direction. The dolly 4132 carries a top drive 4130. The dolly 4132 comprises a deployment mechanism 4133 that may be extended or retracted in order to bring the top drive 4130 in alignment with a well centre 4161 for performing drilling related operations. A front side of the dolly system may be defined as the side of the dolly 4132 facing towards the well centre 4161; A back side of the dolly system may be defined as the side of the dolly 4132 facing away from the well centre 4161; A position of the dolly system may be defined as the centre point O of the single vertical rail 4134; A forward direction Dx of the dolly system may be defined as the direction from the centre point O towards the top drive 4130 and the well centre 4161. A transverse direction Dy may be defined as the horizontal direction perpendicular to the forward direction Dx.
(68) FIG. 25 shows a support structure 4250 with two parts, each carrying a vertical rail 4234. A dolly 4232 is guided between the two rails 4234 for travel in a vertical direction. The dolly 4232 carries a top drive 4230 in alignment with a well centre 4261 for performing drilling related operations. A position of the dolly system may be defined as the centre point O of the ensemble of vertical rails 4234. In this embodiment, the position O of the dolly system coincides with the position of the top drive 4230 and the well centre 4261. In this embodiment, a transverse direction Dy may be defined as the horizontal direction connecting the two rails 4234, and a forward direction Dx of the dolly system may be defined as the horizontal direction perpendicular to the transverse direction Dy.
(69) Referring now to FIGS. 26-32 different layouts for the angular orientation of two dolly systems a/b in a dual activity rig with respect to each other are now described with reference to their respective locations O(a), O(b) and forward directions Dx(a), Dx(b), as well as the corresponding transverse directions Dy(a), Dy(b). In FIGS. 26-32, the dolly systems are represented by the embodiment of FIG. 23. However, any dolly system embodiment characterised by a position O, as well as forward and transverse directions Dx, Dy are applicable accordingly.
(70) FIG. 26 shows a face-to-face configuration where the forward directions Dx(a) and
(71) Dx(b) are aligned with each other and point towards each other. The forward direction Dx(a) of the first dolly system (a) is anti-parallel with the forward direction Dx(b) of the second dolly system (b). The angle between the forward directions Dx(a), Dx(b) in this configuration may be defined as zero. FIG. 27 shows a configuration where the dolly systems a, b are oriented to face towards each other, and may therefore be described as a face-to-face “orientation”. However, as compared to the face-to-face configuration of FIG. 26, the forward directions Dx(a), Dx(b) of this configuration enclose an acute angle theta. The well centres served by this angled configuration in face-to-face orientation are located between the dolly systems a, b. FIG. 28 shows a back-to-back configuration where the forward directions Dx(a) and Dx(b) are aligned with each other and point away from each other. As in FIG. 26, the forward direction Dx(a) of the first dolly system (a) is anti-parallel with the forward direction Dx(b) of the second dolly system (b), and the angle between the forward directions Dx(a), Dx(b) is zero. However, in contrast to FIG. 26, the dolly systems are arranged between the well centres served by this configuration. FIG. 29-FIG. 31 show different angled configurations, wherein the angle between the forward directions Dx(a), Dx(b) is about 90 degrees. In the configuration of FIG. 29, the dolly systems (a, b) are oriented towards each other, such that the forward directions Dx(a), Dx(b) converge to a point of intersection in front of both the dolly systems (a, b). In the configuration of FIG. 30, the dolly systems (a, b) are oriented away from each other, such that the forward directions Dx(a), Dx(b) diverge from a point of intersection located on the back side of both dolly systems (a, b). In the configuration of FIG. 31, the dolly system (b) is arranged behind dolly system (a), such that a point of intersection between the forward directions Dx(a) and Dx(b) is arranged in front of dolly system (b) and on the back side of dolly system (a). FIG. 32 shows a side-by-side configuration where the forward directions Dx(a) and Dx(b) are parallel to each other pointing in the same direction, and the transverse directions Dy(a), Dy(b) are aligned with each other, wherein the centre points O(a) and O(b) of the dolly systems ((a, b) are spaced apart from each other in a transverse direction.
(72) FIG. 33 shows schematically a layout of a dual activity rig having a first hoisting system and a dolly system with top drive associated therewith. The dolly system may for example be of the kind shown in FIG. 23. The dual activity rig further comprises a second hoisting system (not shown). However, the second hoisting system is not equipped with a dolly system and top drive. Such a configuration may be characterised with reference to the location of the second hoisting axis with respect to the dolly system associated with the first hoisting system: a forward cooperation zone 4062 is located in a forward direction in front of the of the dolly system and top drive 4030, whereas transversely adjacent zones 4063 may be referred to as sideways cooperation zones.
(73) FIG. 34 shows schematically an advantageous layout according to one embodiment of a dual activity drilling rig configured for individual operation at separate well centres. The dual activity rig has first and second hoisting systems that are equipped with first and second top drives guided by respective first and second dolly systems. This layout has a back-to-back configuration of first and second dollies 4332a/b running on respective vertical tracks 4334a/b attached to respective first and second portions 4350a/b of a common support structure to independently serve operations at the separate first and second well centres 4361a/b, wherein the rig may be supplied from adjacent pipe storage area 4351. In case heavy duty operations require the joint operation of both the first and second hoisting systems, they can be coupled together for joint operation through a joint operation well centre 4361c. To that end, the respective portions of the support structure 4350a/b is split such that a connecting tool according to the above described embodiments may be installed, wherein a tool axis of the connecting tool is aligned with the joint operations well centre 4361c. Operations at the joint operations well centre 4361c may be also be supplied from the adjacent pipe storage area 4351, e.g. through a respective opening/tunnel between the first and second portions of the support structure 4350a/b.
(74) FIG. 35-42 corresponds to FIGS. 14-21 of co-pending PCT application PCT/EP2014/050509 except that the rig further comprises a joint operations well centre, between the two hoisting systems and reachable by hooking up connecting tool according to the invention. The numbering of features follows that of PCT/EP2014/050509 except for the joint operations well centre 3061c. Examples of numberings of FIGS. 35-42 and their corresponding numbers in FIG. 1-34 include: Well centre 1423 and 2423 corresponds to 3061a/b Stationary sheaves 1433 or movable 2533 correspond to 3044a/b because the type of hoisting system in FIG. 19 could be that of FIG. 35 or 36. Top drives 2437 corresponds to 3030a/b Mast 1404 or 2404 corresponds to 3050
Other correspondences will be clear to the skilled person.
(75) FIG. 35 illustrates another embodiment of an offshore drilling rig. The drilling rig of FIG. 35 is a drillship having a hull 1401. The drilling rig comprises a drill floor deck 1407 formed on top of a substructure 1497. The substructure comprises a platform supported by legs. The platform defines the drill floor deck and spans across a moon pool formed in the hull of the drillship. The drill floor deck 1407 comprises two holes defining well centres 1423 (referred to as 3061a/b in FIG. 19) located next to a dual activity mast 1404. The rig also comprises a joint operations well centre 3061c which can be reach by hooking a connecting tool to the two hoisting system (e.g. directly to the hook and/or to either of the top drives). The direction intersecting with both well centres defines a transverse direction which, in this case, is parallel with a longitudinal axis of the drillship. The dual activity mast 1404 is supported by the substructure 1497 and extends upwardly from the drill floor deck 1407. The mast comprises two mast portions arranged side by side in the transverse direction such that they are both located on the same side relative to the well centres. Each mast portion accommodates a hoisting system, each for lowering a drill string through a respective one of the well centres 1423 towards the seabed. In the example of FIG. 35, the hoisting system is a draw-works system where the hoisting line is fed over stationary sheaves 1433 carried by support members. The drawworks motor/drum (not shown) may be positioned at a suitable location on the drilling rig. Alternatively, other hoisting systems such as a hydraulic hoisting system may be used, as will be illustrated below. Each well centre is located next to one of the mast portions and the corresponding hoisting system. The position of each of the well centres relative to the corresponding hoisting system defines a longitudinal direction, in this example the transverse direction of the drill ship.
(76) The side-by-side configuration of the dual activity mast and well centres allows for efficient dual operations, easy access to both well centres, and convenient visual control of both well centres from a single driller's cabin 1434 which may e.g. be positioned symmetrically relatively to the well centres but displaced from the axis connecting the well centres, e.g. within the footprint of the mast. The driller's cabin may be split up into two or more cabins.
(77) The drilling rig comprises a setback structure 1412 or similar pipe storage structure for storing stands of tubulars such that the stored tubulars are located partly or completely below the level defined by the drill floor deck, i.e. below the uppermost platform of the substructure 1497 and partly covered by the drill floor deck 1407. The setback structure comprises a support framework supporting fingerboards having horizontally extending fingers between which tubulars may be stored. The setback structure is positioned and arranged so as to allow stands to be moved to/from both well centres from/to the setback. To this end, on or more column rackers or similar vertical pipe handling equipment may be arranged to move stands into and out of the setback structure 1412. The handling of tubulars to and from the setback area 1412 will be illustrated in more detail in connection with the embodiments described below. In some embodiments, e.g. in case of stands of drill pipe or casings, the tubulars may be taller than the drill floor. Hence, when they are stored in the setback structure in an upright orientation their uppermost ends may extend above the drill floor level. When feeding them to one of the well centres they may be laid into a chute as will be described below. Alternatively, the setback structure may extend from the drill floor deck upwards. The handling of tubulars within the setback area may be performed by vertical pipe rackers or the like. The setback structure 1412 further comprises stand building equipment 1477 configured to build stands from individual pieces of pipe. An example of such stand building equipment is described in WO 02/057593. Alternatively or additionally, stands may be built on the drill floor.
(78) In some embodiments, each mast portion and hoisting system form a respective gap between the two support members that carry the sheaves 1433, through which gap tubular equipment is movable between the setback structure 1412 towards the respective well centres.
(79) Optionally, the drilling rig further comprises a pipe storage area 1409 for storing pipes in horizontal orientation located towards the bow of the drillship, i.e. transversely displaced from the well centres. One or more catwalk machines 1408 or similar horizontal pipe handling equipment are arranged to feed tubulars from the storage area 1409 or from other storage areas to the well centres. To this end, the catwalk machines are aligned with the axis defined by the two well centres. These catwalk machines 1408 and one or more stores for (e.g. 1409) or aft (not shown) may be used in combination or as an alternative to having riser 1415 stored below the drill deck. In the embodiment of FIG. 35 the catwalk machines 1408 may be used to provide additional riser joints, load the riser storage below the drill deck and/or to provide the drill floor with other tubulars. One or each of the catwalk machines may be operable to service both well centres. Moreover the drilling rig comprises one or more further catwalk machines travelling on tracks 1476 and configured to feed tubulars from the pipe storage area 1409 or from other storage areas on the opposite side of the mast (towards the aft of the ship) to the stand building equipment 1477. The catwalk machine(s) travelling on tracks 1476 is/are configured to travel along a direction parallel with the catwalk machines 1408, but on the other side of the mast. In the present embodiment, one or more catwalk machines may be operable to travel along a substantial portion of the length of the drillship. It will be appreciated that, in some embodiments, each catwalk machine may be configured to only travel to/from the stand building equipment 1477 without being configured to pass the stand building equipment. Consequently, the drilling rig may comprise two catwalk machines travelling on tracks 1476 on respective sides of the stand building equipment so as to be able to feed tubulars to the stand building equipment from both sides. The stand building equipment 1477 may thus receive pipes from the catwalk machine on tracks 1476, bring them in upright orientation, and connect them to other pipes as to form stands. The stands may then be placed in the setback structure for future use.
(80) The drilling rig comprises another storage area 1415 below the drill floor deck 1407 and configured for storing risers in a vertical orientation. The risers may then be moved, e.g. by means of a gantry crane and respective chutes or other suitable pipe feeding equipment through holes in the drill floor, as will be described in more detail in connection with the description of the further embodiments below.
(81) As the mast structure 1404 is located on one side of the well centres, and since the setback area is located on the side of the mast opposite the well centres and/or behind the driller's cabin 1434, the drill floor deck provides a large, unobstructed deck area on the side of the well centres opposite the mast. This area provides unobstructed access to both well centres and is free of pipe handling equipment. Consequently, these areas may be used as working area, e.g. for rigging up suspendable auxiliary equipment, and/or for positioning on-deck auxiliary equipment. Generally, riser joints and/or other tubulars may be tilted between an upright and a horizontal orientation by a tilting apparatus as described in co-pending Danish patent application no. PA 2013 00302, the entire contents are hereby included herein by reference.
(82) FIGS. 36-42 show another embodiment of a drilling rig, in this example of drillship having a hull 2501, similar to the drilling rig of FIG. 35 but with a different mast structure and hoisting system. In particular, FIGS. 36 and 37 show 3D views of the drill floor seen from the starboard and port sides of the drillship, respectively (a part of the hull of the ship is cut away in FIG. 37); FIGS. 38 and 39 show horizontal cross sections in a plane above the drill floor and a plane below the drill floor, respectively; FIGS. 40 and 41 show lateral cross sections of the drill ship. Finally, FIG. 42 shows another 3D view of the drill floor seen from the starboard side of the drillship.
(83) As in the example of FIG. 35, the drilling rig of the present embodiment comprises a drill floor deck 2407 formed on top of a substructure 2897. The substructure comprises a platform supported by legs. The platform defines the drill floor deck and spans across a moon pool 2722 formed in the hull of the drillship. The drill floor deck 2407 comprises two holes defining well centres 2423 (referred to as 3061a/b in FIG. 19), one or both being equipped with a diverter housing. The rig also comprises a joint operations well centre 3061c which can be reach by hooking a connecting tool to the two hoisting system (e.g. directly to the hook and/or to either of the top drives). The mast includes two mast portions, each associated with, and adjacent to, one of the well centres. In the present example, the well centres are located outside the footprint of the mast 2404 as described in detail in connection with FIG. 14. As in the previous embodiments, the direction between each well centre and the associated hoisting system defines a longitudinal direction. In this example, the direction intersecting with both well centres defines a transverse direction which, in this case, is parallel with a longitudinal axis of the drillship. The dual activity mast 2404 is supported by the substructure 2897 and extends upwardly from the drill floor deck 2407. Each mast portion accommodates a respective hydraulic hoisting system each for lowering a drill string through a respective one of the well centres 2423 towards the seabed. Each hydraulic hoisting system comprises cylinders 2406, respectively, that extend upwardly from the drill floor deck and support the load to be lowered or hoisted. Each well centre is located next to one of the mast portions and the corresponding hoisting system; both well centres are located on the same side relative to the mast, i.e. in a side-by-side configuration.
(84) The cylinders 2406 of each hoisting system are arranged in two groups that are positioned displaced from each other in the transverse direction so as to form a gap between the two groups. Each gap is thus aligned with a respective one of the well centres along the longitudinal direction and is shaped and seized so as to allow tubulars to be moved through the gap towards the respective well centre and even raised into an upright position while being located at least partly in the gap between the cylinders. The exact shape, size and location of the gap may depend on the type of tubular to be fed through the gap, e.g. whether the gap is to be used for feeding drill pipes, casings and/or riser through the gap. The well centre is longitudinally displaced from the gap. The rods of the cylinders support respective sheaves 2533, e.g in the form of a sheave cluster, over which the hoisting wires 2484 are suspended. The cable sheaves 2533 define an axis that is parallel to the direction connecting the two groups of cylinders of one of the hoisting systems. One end of the hoisting wires 2484 is anchored to the drilling rig, while the other end is connected to top drive 2437 or hook of the corresponding hoisting system, via a travelling yoke 2187. The sheaves 2533 are laterally supported and guided by the respective mast portions. Each top drive 2437 is connected via a dolly 2569 to a vertical track arranged at the mast 2404. The fixed ends of the hoisting wires are anchored via a yoke 2482 and respective sets of deadline compensators 2483. The compensators 2483 are also arranged in two groups so as to form a gap over which the yoke 2482 extends. Hence, tubulars can pass through the gap between the compensators 2483 and below the yoke 2482.
(85) The side-by-side configuration of the dual activity mast and well centres allows efficient dual operations, easy access to both well centres, and convenient visual control of both well centres from a single driller's cabin 2433 which may e.g. be positioned transversely between the well centres, e.g. within the footprint of the mast.
(86) The drilling rig further comprises a pipe storage area 2509 for storing pipes in horizontal orientation and catwalk machines 2508 or other horizontal pipe handling equipment for transporting pipes between the storage area 2509 and the well centres 2423, also as described in connection with FIG. 35.
(87) The drilling rig comprises a setback structure 2512 or similar pipe storage structure for storing stands of tubulars below the substructure 2897 and partly covered by the drill floor deck 2407. The setback structure comprises a support framework 2590 supporting fingerboards having horizontally extending fingers between which tubulars may be stored. One or more column rackers 2491 or similar vertical pipe handling equipment may be arranged to move stands into and out of the setback structure 2512. The setback structure 2512 further comprises stand building equipment 2677 configured to build stands from individual pieces of pipe through a foxhole 2592. The setback structure 2512 is located adjacent the moon pool 2722 laterally displaced from the axis defined by the well centres.
(88) Moreover the drilling rig comprises one or more further catwalk machines (not shown) configured to feed tubulars from the pipe storage area 2509 or from other storage areas on the opposite side of the mast (towards the aft of the ship) to the stand building equipment 2677, all as described in connection with FIG. 35. The stand building equipment 2677 may thus receive the pipes from the catwalk machine, bring them in upright orientation, and connect them to other pieces so as to form stands. To this end the stand building equipment may comprise a mousehole 2589 through which the stand may be gradually lowered while it is made up until the lowermost end of the stand is at the lowermost level of the setback area 2512, while the uppermost end of the stand is below the drill floor level. The stands may then be received by pipe rackers 2491 and placed in the setback structure 2512 for future use. To this end the pipe rackers are operable to traverse across the setback area, e.g. in the direction parallel to the direction connecting the well centres.
(89) The drilling rig comprises a number of slanted chutes 2592 each for feeding pipes from the setback area 2512 to one of the well centres. Each chute 2592 receives pipes from one of the pipe rackers 2491 feeds the pipes in a slanted upward direction through a corresponding slit 2485 in the drill floor and through the gap formed by the cylinders 2406 of the corresponding hoisting system towards a respective one of the well centres 2423, where they are picked up at their uppermost end by the corresponding hoisting system and lifted through the slit 2485 until they are vertically suspended above the corresponding well centre. To this end, the drilling rig further comprises pipe handling equipment operable to guide the pipes while they are being lifted through the slit 2485. The slits 2485 are elongated and point away from the axis connecting the well centres and towards the side where the setback area 2512 is positioned.
(90) The drilling rig comprises another storage area 2515 below the drill floor deck 2507 and configured for storing risers in a vertical orientation, as described in connection with FIG. 35. The riser storage area 2515 is located adjacent the moon pool 2722, e.g. on the side of the moon pool opposite the setback structure 2512. The risers may be moved, e.g. by means of a gantry crane and respective chutes 2794 or other suitable pipe feeding equipment through holes 2481 in the drill deck floor. The riser feeding holes 2481 may be covered by plates, hatches or similar covers. In FIG. 36, the holes are shown in the open position with the uppermost end of a riser extending through the open hole. The riser feeding holes are displaced from the axis connecting the well centres.
(91) As in the previous example, in the embodiments of FIGS. 35-42 a main deck is located beneath the drill floor deck and allows heavy subsea equipment, e.g. BOPS and Christmas trees to be moved to the moon pool under the well centres so as to allow such equipment to be lowered toward the seabed. Consequently, the drill floor deck and, in particular, the part of that drill floor deck that is located in close proximity to the well centre may be stationary and does not need to be hoisted or lowered for the subsea equipment to be lowered to the seabed.
(92) As the stands of tubulars and the risers are stored below the drill floor deck, and since the catwalk machines 2508 extend towards opposite sides from the well centres, and since the mast structure 2404 is located on one side of the well centres, the drill floor deck provides a large, unobstructed deck area on the side of the well centres opposite the mast. This area provides unobstructed access to both well centres and is free of pipe handling equipment. Consequently, these areas may be used as working area, e.g. for rigging up suspendable auxiliary equipment, and/or for positioning on-deck auxiliary equipment. In particular, when no riser operations are performed, the holes 2481 may be covered or otherwise secured. Moreover, at least parts of the setback structure 2512 may be covered by a platform so as to provide additional storage or working area.
(93) Even though the embodiments of FIGS. 35-42 have been described in the context of a drillship, it will be appreciated that the described features may also be implemented in the context of a semi-submersible or other type of drilling rig. In particular, storage of risers and/or other tubulars below the drill floor deck may be implemented on other types of drilling rigs as well.
(94) Although some embodiments have been described and shown in detail, the invention is not restricted to them, but may also be embodied in other ways within the scope of the subject matter defined in the following claims. In particular, it is to be understood that other embodiments may be utilized and structural and functional modifications may be made without departing from the scope of the present invention.
(95) The mere fact that certain measures are recited in mutually different dependent claims or described in different embodiments does not indicate that a combination of these measures cannot be used to advantage.
(96) It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.
