Abstract
An offshore drilling rig including a drill floor deck having one or more holes, each defining a well center; one or more masts upwardly extending relative to the drill floor deck, and one or more hoisting systems, each supported by at least one of the one or more masts and configured for hoisting and lowering tubular equipment through at least one of the one or more well centers; a storage area for accommodating marine riser joints in upright orientation side by side in respective upright storage positions; a riser handling apparatus, different from the hoisting systems, adapted to move at least one of said marine riser joints along a movement path between its upright storage position and a prostrate maintenance/transfer position on a maintenance/transfer area, which movement path does not intersect any of the well centers.
Claims
1. A riser maintenance station for a drilling rig comprising: a riser manipulation device including mounting elements configured to secure opposite ends of a riser, wherein the riser has a plurality of buoyancy elements secured thereto; said mounting elements being configured such that the riser can be elevated to allow a 360 degree inspection along a length of the riser such that one or more of the buoyancy elements can be removed or attached from/to the riser while the riser is in a horizontal position at the riser maintenance station.
2. The riser maintenance station of claim 1, wherein the riser manipulation device is operable to elevate one or both ends of the riser while the riser is located in a horizontal position at the riser maintenance station.
3. The riser maintenance station of claim 1, wherein the riser manipulation device is operable to rotate the riser around its longitudinal axis while the riser is located in a horizontal position at the riser maintenance station.
4. The riser maintenance station of claim 1, wherein the riser maintenance station further comprises one or more riser maintenance machines operable to perform one or more maintenance operations on the riser.
5. The riser maintenance station of claim 1, wherein the riser maintenance station further comprises sandblasting equipment or riser inspection equipment insertable into the riser.
6. The riser maintenance station of claim 1, further comprising a protective enclosure shaped and sized to accommodate one or more risers in a prostrate position separated from each other so as to allow service personnel to access each of the one or more risers from both lateral sides of the riser.
7. The riser maintenance station of claim 6, wherein the enclosure is a housing completely enclosing the riser.
8. The riser maintenance station of claim 6, wherein the enclosure is a structure that encloses the circumference of the riser but that has one or two open ends, or ends covered by doors.
9. The riser maintenance station of claim 6, wherein the enclosure comprises an access opening roof or wall to allow risers to be moved into and out of the enclosure.
10. The riser maintenance station of claim 7, wherein the enclosure comprises an access opening roof or wall to allow risers to be moved into and out of the enclosure.
11. The riser maintenance station of claim 8, wherein the enclosure comprises an access opening roof or wall to allow risers to be moved into and out of the enclosure.
12. The riser maintenance station of claim 8, further comprising a riser bay.
13. The riser maintenance station of claim 1, wherein said mounting elements and bed being configured such that the riser can be rotated to allow a 360 degree inspection of the riser.
14. A riser maintenance station for a drilling rig comprising: a riser manipulation device including mounting elements configured to secure opposite ends of a riser, wherein the riser has a plurality of buoyancy elements secured thereto; the riser manipulation device further including a bed for supporting the riser in a horizontal position; wherein the riser manipulation device is operable to move the riser longitudinally while the riser joint is located in a horizontal position at the riser maintenance station.
15. The riser maintenance station of claim 14, wherein the riser manipulation device is operable to move the riser longitudinally and laterally while the riser is located in the horizontal position at the riser maintenance station.
16. The riser maintenance station of claim 14, wherein the riser manipulation device further includes a bed for supporting the riser in a horizontal position.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) FIG. 1 shows a semi-submersible drilling rig.
(2) FIG. 2 shows an example of a riser tilting apparatus where the riser joint is pivoted around a pivot axis.
(3) FIG. 3 shows an example of a riser tilting apparatus where the riser joint is put on the floor of a riser bay.
(4) FIGS. 4a-f show an example of a riser tilting apparatus.
(5) FIG. 5 illustrates an example of a riser enclosure placed on a deck of a drilling rig.
(6) FIG. 6 illustrates an example of a riser enclosure placed inside the hull of a drilling rig.
(7) FIG. 7 illustrates an example of walkways providing access to a riser.
(8) FIG. 8 (a, b, c) shows examples of handling a riser in a horizontal position.
(9) FIG. 9 shows an example of a riser support mechanism.
(10) FIG. 10 illustrates a side view of an example of a riser handling apparatus.
(11) FIG. 11 schematically illustrates different examples of a deck layout of a drilling rig.
(12) FIG. 12 shows another example of a riser tilting apparatus.
(13) FIG. 13 shows another example of a riser tilting apparatus and a riser maintenance station.
(14) FIGS. 14A-B show an example of a drillship comprising a riser tilting apparatus and a riser maintenance station.
(15) FIG. 1 shows a semi-submersible drilling rig 100 and how the riser joints 105 are loaded from a supply vessel 107 onto the rig, horizontally placed on the maintenance/transfer bay 106 at an edge of a riser bay 104, and then tilted into upright position by the riser handling apparatus 108, and stored in upright position in the riser bay 104. The riser joints may be moved between the vessel 107 and the maintenance/transfer bay 106 by a crane (not shown in FIG. 1) such as a knuckleboom crane, of the drilling rig.
(16) In this example the drilling rig 100 is a semisubmersible drilling rig but other rig types using vertical storage of riser joints are also feasible. The rig 100 comprises pontoons (not shown) from which support columns 123 extend upwardly, and a topside platform 124 supported by the columns 123. During operation, the drilling rig floats at the ocean surface with the pontoons under the water and the support columns extending out of the water such that the topside platform is elevated above the water. To this end, the pontoons may be filled with ballast water so as to cause the rig to be submersed to the desired level.
(17) The topside platform comprises a main deck 125 and a drill floor deck 126 arranged elevated from the main deck. In other embodiments, the drill floor deck may be on the same level as the main deck.
(18) FIG. 1 further shows the mast 103 including the main hoisting system for raising/lowering tubular equipment through the well centre, a pipe setback area 102 for drill pipes and catwalk machines 101 for advancing drill pipes to the mast 103. As can be seen, the loading/offloading of the riser joints from/to a supply vessel 107 does not involve the mast 103 or the catwalk machines 101, i.e. does not interfere with the drilling operation because the machines handling drill pipe and/or casing are not substantially affected. The drilling rig of FIG. 1 further comprises an accommodation structure 127 for the drill crew and other personnel. The accommodation structure is positioned right next to the riser bay 104, i.e. the riser bay 104 is sandwiched between the mast 103 and the accommodation structure 127. It will be appreciated that, the deck layout may be different from the example of FIG. 1. However, it is generally desirable to provide an efficient utilisation of the limited space on a drilling rig and often the riser storage area is positioned in close proximity to other structures. It is therefore desirable to facilitate riser handling that does not require unnecessary space and that interferes only little, if at all, with other operations, in particular the drilling operation. While other positions of the riser storage are possible as well, when the riser storage area is located directly next to the mast as in the example of FIG. 1, riser joints may be fed efficiently to the well centre, e.g. using a chute. When tubulars other than riser joints, such as drill pipes, are stored on another side of the mast 103, e.g. a side opposite from the riser joints as in FIG. 1, a particularly efficient handling of tubulars is provided and concurrent handling of drill pipes and riser joints is further facilitated.
(19) FIG. 2 shows an example of a riser tilting apparatus where a riser joint is pivoted around a pivot axis 212 and placed on the main deck while supported by a pivotable, elongated support member 213. The elongated support member 213 has mounting elements 215 at its respective ends that laterally extend from the support element. The mounting elements may be operable to elevate the riser joint in its vertical position and/or to rotate the riser joint around its axis.
(20) FIG. 3 shows an example of a riser tilting apparatus where the riser joint is lowered onto the floor of the riser bay 104, typically using a gantry crane 309 that traverses the riser bay. During the tilt operation, the upper end of the riser joint may be suspended from and supported by the gantry crane 309. To this end, the gantry crane comprises a grapping tool 313 or another suitable attachment tool for attachment to an end of the riser joint allowing the riser joint to be lifted and moved. The riser joint is moved to the tilting apparatus and the lower end of the riser joint is attached to a pivoting mount 310 positioned at or near the floor of the riser bay, e.g. at or near a side wall of the riser bay. During this movement, the riser joint only needs to be elevated from the floor of the riser bay sufficiently high so as to allow free movement of the riser joint in its upright orientation across the floor of the riser bay. After being fastened to the pivoting mount 310, the gantry crane 309 guides the riser joint downwards in a tilting motion as indicated by arrows 311 and 312, such that the riser joint ends up resting on the floor of the riser bay 104. To this end, the grapping tool 313 may comprise a pivotable element, e.g. as illustrated in FIG. 3. In some embodiments, once the riser joint is positioned in the floor of the riser bay, it may be axially moved e.g. through an opening in one of the side walls of the riser bay and into a maintenance station.
(21) In some embodiments, having the riser joint fixed at both ends provides for a controlled flipping motion. It is typical for drilling vessels having vertical riser storage that a gantry crane is used to pick up riser joints from the storage position and to transport them in upright orientation towards the drill floor/well centre. In some embodiments the same gantry crane is used to perform the function of the gantry crane 309. However, compared to a conventional gantry crane for handling risers, the gantry crane 309 has an extended reach to allow the riser grapping tool 313 to be extended further towards the bottom of the riser bay. In some embodiments the grapping tool can be operated in a vertical range of more than 1 meter, such as more than 5 meters, such as more than 10 meters, such as more than 15 meters, such as more than 20 meters, such as more than 25 meters. In some embodiment the gantry crane 309 is arrange so that the riser grapping tool allows tilting of a grapped riser joint by about 90 degrees. In some embodiments a separate grapping tool is mounted for moving risers towards the drill floor with little or no allowance for tilting of the riser and the flipping operation with a larger allowance for tilting such as at least up to 90 degrees. In some embodiments an overhead crane, such as a knuckle-boom crane, performs the function of the gantry crane 309.
(22) FIG. 4 shows another example of a riser tilting apparatus. During the tilt operation, the upper end 410 of the riser joint 105 may be fastened to and be suspended from a gantry crane 309 that transverses the riser bay 104 where it is understood that the gantry crane 309 may share one or more of the features discussed in relation to the gantry crane of FIG. 3. The lower end of the riser joint is supported and lifted by an elevator 411. Hence, as illustrated in FIG. 4a, the riser joint is first moved in upright orientation from its storage position onto a riser elevator 411 that may slide one end of a riser 105 between a position at the floor of the riser bay 104 and up to or above the main deck level 125 or another operational deck of the platform. The elevator is lifted, while the gantry crane 309 lowers the upper end of the riser joint so as to tilt the riser joint into horizontal position, as illustrated in FIGS. 4b-4e. Finally, the riser joint is moved axially onto the maintenance/transfer position as illustrated in FIG. 4f. While FIGS. 4b-e illustrate a process where the elevator 411 is lifted concurrently with the lowering of the gantry crane 309, it will be appreciated that, alternatively, the gantry crane may initially lower the upper end of the riser joint while the elevator remains in its bottom position, e.g. similar to the tilting operation shown in FIG. 3. Once in a horizontal orientation, the gantry crane and the elevator may then be lifted so as to raise the riser joint while in horizontal orientation.
(23) FIG. 5 illustrates an example of a riser enclosure 501 placed on a deck 125 of a drilling rig. When the riser joint 105 has been moved to a horizontal position it can be enclosed to accommodate various tasks being performed on the riser. Such an enclosure may be used to protect people working on the riser from adverse weather but may also be applied to shield operations such as sand blasting and painting. The enclosure can be located on, for example, the main deck 125. In this example the enclosure is shown in conjunction with the riser tilting apparatus of FIG. 2, but it might just as well be used with other embodiments of riser tilting apparatus, for example, but not limited to, the ones shown in FIGS. 3 and 4. The shape, size and exact location may vary accordingly, for instance the enclosure may be expandable, have a telescopic functionality and/or be removable. In some embodiments the enclosure can be opened or removed to allow a riser joint to be moved in or out in the horizontal position. In some embodiments the enclosure is elevated above the main deck 125 along with the riser joint when placed in the horizontal position e.g. to allow, for instance, a forklift to pass underneath.
(24) FIG. 6 illustrates another example of storing a riser joint 105 horizontally in an enclosed space 601 with the purpose of performing various tasks on the riser joint. In this example the riser joint 105 is elevated and moved to a horizontal position. It is then moved axially into the hull of the platform 124 through a designated hatch 602 in the side wall of the riser storage bay and into a closed compartment 601 inside the platform. It should be noted that several degrees of enclosure of the riser can be achieved, i.e. by moving the riser joint further or less into the hull 124, so the riser joint is either fully or partly enclosed. In one embodiment the riser joint is placed partly in the compartment in the hull and a removable/collapsible enclosure is use to enclose the entire riser joint. It will further be appreciated that the closed compartment 601 may be provided at different levels relative to the main deck and relative to the floor of the riser bay. For example, the closed compartment may be located on the same level as the floor of the riser bay, thus allowing the riser joint to be axially moved into the compartment, once the riser joint has been lowered on the floor of the riser bay, e.g. as described in connection with FIG. 3 above, without the need for lifting the riser joint to another level. In jet another embodiment the riser joint may be lowered into an enclosed space underneath the floor of the riser bay, e.g. by an elongated elevator; or through an elongated hatch in the floor of the riser bay.
(25) FIG. 7 illustrates an example of walkways providing access to a riser joint 105 placed horizontally on a drilling rig, e.g. drilling rig 100 of FIG. 1. In order to perform various tasks requiring the presence of personnel, a means of access to the whole length of the riser joint is often desirable. In this example the walkway 701 is fixed to the elongated support member 213, e.g. an elongated support member as described in FIG. 2, and located on the main deck 125. In this example the enclosure is shown in conjunction with riser tilting apparatus of FIG. 2, but might just as well be used with other embodiments of riser tilting apparatus, for example, but not limited to, the ones shown in FIGS. 3 and 4. Walkways are relevant in the case where e.g. the riser joint has a full or partial overhang, for example over the riser bay 104, or if the horizontal maintenance/transfer position of the riser is elevated from the deck.
(26) The access ways as shown in FIG. 7 may be fixed rigidly to a support structure as shown, but other solutions may also be applied, e.g. the walkways may be moved into place by means of a skid or rail system, by being lifted in place by a crane or lifting system or it could be foldable (such as fold up along the sides of the elongated support member) to save up space in the support structure's vertical position.
(27) FIGS. 8 a, b, c show examples of handling a riser joint in a horizontal position. When the riser joint is placed in a horizontal position, there are several ways of manipulating it in order to perform the desired tasks. In some embodiments the riser joint is placed in a handling apparatus 803 able to lift and/or rotate the riser joint. In some embodiments the functionality of the handling apparatus is integrated into the maintenance/transfer bay. In some embodiments the functionality of the handling apparatus is integrated into the elevator of FIG. 4 or the elongated support member which, in some embodiments, acts as the maintenance/transfer bay when the riser joint is held in the horizontal orientation/position. In FIG. 8a the riser joint 105 is resting on a bed 801 which is connected to mounting elements 802, 804 mounted at each end of the bed 801 and operable to support respective ends of the riser joint 105. In some embodiments one or more of the mounting elements 802, 804 are removable from the bed 801 for instance to provide a more compact arrangement when the handling apparatus is not in use. In some embodiments the mounting elements 802, 804 comprise riser grapping/stabbing tools arranged for engagement/disengagement with the riser placed on the bed 801, thus allowing the riser joint to be lifted in or out of the bed 801 in a horizontal position.
(28) FIG. 8b shows the riser joint elevated by means of the mounting elements 802, 804. In this position the whole outer geometry of the riser joint is accessible for instance to allow 360 degree inspection of the riser, to allow removal and/or mounting of buoyancy elements, painting and/or sand blasting.
(29) FIG. 8c illustrates an alternative means of achieving the above described movement options. By means of a gantry crane 309 pinning the riser at one end, and a mounting element 802 pinning it at the other, the riser can be elevated and rotated. A bed (not shown) similar to the bed 801 can also be included to allow the riser joint to be lifted in or out of the bed 801 in horizontal position. When the riser joint is placed in the horizontal position using the gantry crane 309 and without an elongated support member 213, the bed 801 may be removable to allow the riser joint to be positioned vertically in the bay as well as being lifted in or out of the bed 801 in horizontal position. It will be appreciated, though not explicitly shown in FIG. 8, that the handling apparatus may be enclosed or enclosable in an enclosure, e.g. as described in connection with FIG. 5 or 6.
(30) FIG. 9 shows an example of a riser support mechanism 901. A riser joint 105 is shown to be elevated on the way to a maintenance/transfer bay (not shown), for example in a manner similar to that shown in FIG. 4. The riser joint 105 is located at the top of the riser bay 104 and level with the maintenance/transfer bay—in this case also the main deck. In many cases the riser joint will be raised at least a little above the main deck 125 to allow for a bed to be positioned under the riser joint. To allow the riser to be shifted onto the maintenance/transfer bay, a device 901 is provided with an arm structure 903 for moving a support member 902 out over the riser bay and under the riser joint 105 so as to provide support to the riser joint. This allows the riser elevator 411 to remove its support of the riser joint and to slide out of the way to allow the riser joint, now supported by the support member 902, to be slid onto the main deck 125. Alternative embodiments performing the described support function include a sliding skid system embedded in the main deck, a dedicated support device moving parallel to the edge of the riser bay or allowing the support structure of the riser elevator 411 to skid onto the main deck 125 or maintenance/transfer bay 106, or other support devices that allow movement of a riser in prostrate orientation along the axial and/or lateral direction of the riser joint.
(31) FIG. 10 illustrates an embodiment of a riser handling apparatus 1001 similar to the apparatus of FIG. 2 and operable as a maintenance/transfer bay where the riser joint 105 can be elevated and rotated for maintenance as indicated by arrow 1002 and arrow 1003, allowing for removal of buoyancy elements 1004. FIG. 10 further illustrates how a riser joint may be lifted (arrow 1005) onto the apparatus by a crane (e.g. when offloading the riser joint from a supply ship), and how the riser joint can be tilted into upright position for storage in the riser bay (arrows 1006 and 1007).
(32) FIG. 11 schematically illustrates different examples of a deck layout of a drilling rig 100 where the maintenance/transfer position 1101 is positioned at different locations. The deck layout shows the position of the main mast 103 above the well centre, the riser bay 104, storage areas 1102 for drill pipes, deck cranes 1103, and the maintenance/transfer bay 1101. The given positions serve to illustrate examples, other variations may also apply. The deck cranes 1103 may e.g. be used for offloading/loading riser joints between the maintenance/transfer position 1101 and a supply vessel. As can be seen in FIG. 11, the riser joints are stored side by side, e.g. supported by fingerboards or another suitable arrangement. The storage positions are arranged such that they leave passageways 1106, 1105 allowing riser joints to be moved in upright orientation towards the well centre along passageway 1105 and towards the tilting position 1107 along passageway 1106. In particular, when the titling position is located in longitudinal extension of or at a longitudinal end of a straight passageway, the tilting of the riser joint is facilitated without interfering with other, stored riser joints.
(33) FIG. 12 shows an example of a riser tilting apparatus similar to that of FIG. 2. However in this case the elongated support member 213 is extendable in the axial direction as shown by arrow 1202 so that the top mounting element 1201 can raise a riser joint mounted in apparatus. A lower mounting element (similar to the mounting element 215, not shown) is optional but can be arranged to follow the riser joint upwards as the support member extends. Alternatively the elongated support is telescopic and optionally without the lower mounting. This has the effect that the pivoting point is moved downwards relative to and along the riser joint, causing the riser joint to extend further away from the bay when placed in the horizontal position in the maintenance/transfer bay. This may for example provide a clearer path for lifting a riser in and out of the riser/maintenance bay.
(34) Generally, the force needed to raise the riser and the support can be supplied by the apparatus e.g. via a lifting cylinders or a pulley system arranged to extend or contract the support member 215. In some embodiments all or a part of the external force may be applied by an overhead crane e.g. coupled to the top mounting element 1201. In this way a mechanically simple device is achieved.
(35) FIG. 13 shows another example of a deck layout of a drilling rig comprising a riser tilting apparatus and a riser maintenance station. The deck layout of FIG. 13 is similar to one of the deck layouts shown in FIG. 11. The drilling rig comprises a main mast 103 above the well centre, a riser bay 104, storage areas 1102 for drill pipes, deck cranes 1103, an accommodation structure 1327, and a riser tilting apparatus 1313. The given positions serve to illustrate examples, other variations may also apply. The deck cranes 1103 may e.g. be used for offloading/loading riser joints between the tilting apparatus 1313 and a supply vessel. The riser bay is recessed below the level of the main deck. The riser joints are stored side by side, e.g. supported by fingerboards or another suitable arrangement. The storage positions are arranged such that they leave passageways 1106, 1105 allowing riser joints to be moved in upright orientation towards the well centre along passageway 1105 and towards the tilting position along passageway 1106.
(36) The riser tilting apparatus may be of the type shown in FIG. 2 or FIG. 12. When the riser tilting apparatus is tilted into its horizontal position, the riser tilting apparatus is positioned alongside the accommodation structure 1327. The accommodation structure may e.g. be a building having two or more floors and be configured to provide accommodation for personnel, work areas and or storage areas, and/or the like. In this embodiment, the accommodation structure 1327 comprises a riser maintenance shop 1328 located on the same level as the main deck. The riser maintenance shop 1328 comprises a lateral opening (which may be closed by gates or the like) allowing a riser joint to be moved between the riser tilting apparatus 1323 and the maintenance shop 1328. To this end, mounting elements 1382 and 1384 and/or a riser bed may be movably arranged, e.g. on skid beams 1385 and 1386, between a position adjacent the riser tilting apparatus and a position inside the maintenance shop 1328.
(37) FIG. 14A shows an example of a drill ship comprising a drill floor 1426 with two well centres 1483 and a dual activity mast 103 for lowering a drill string through one or both of the well centres. The drillship further comprises a riser bay 104 for storing marine riser joints. As in the previous examples, the riser bay may be recessed below the level of the main deck. The riser joints may be stored side by side, e.g. supported by fingerboards or another suitable arrangement. The riser joints may be fed from the riser bay towards the respective well centres, e.g. by means of a gantry crane and respective chutes or other suitable pipe feeding equipment, e.g. through holes in the drill floor.
(38) FIG. 14B schematically illustrates the drillship of FIG. 14A but where a riser tilting apparatus 1413 and a riser station 1427 for maintenance and/or for loading/offloading risers onto/from the drillship have been installed. It will be appreciated that a riser tilting apparatus 1413 and a riser station 1427 for maintenance and/or for loading/offloading risers onto/from the drillship may also be installed on other types of drill ships. The given positions of the riser tilting apparatus and the riser maintenance/loading bay serve to illustrate examples, other variations may also apply. For example, the riser maintenance/loading bay may be oriented along the longitudinal axis of the ship, as illustrated in FIG. 14, or along a transverse axis. Similarly, the maintenance/loading bay may be located fore or aft of the riser maintenance bay/loading and/or towards the port and starboard side of the ship. The riser tilting apparatus and/or the maintenance/loading bay may be oriented relative to the riser bay in a variety of ways, e.g. as described in connection with FIGS. 11 and 13. The riser tilting apparatus may be of the type shown in FIG. 2 or FIG. 12 and/or it may be positioned alongside or integrated into another structure, e.g. as described in connection with FIG. 13.
(39) 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 utilised and structural and functional modifications may be made without departing from the scope of the present invention.
(40) In device claims enumerating several means, several of these means can be embodied by one and the same item of hardware. 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.
(41) 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.
