WO2017051198A2 - Improvements relating to jackup rigs - Google Patents

Improvements relating to jackup rigs Download PDF

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Publication number
WO2017051198A2
WO2017051198A2 PCT/GB2016/052982 GB2016052982W WO2017051198A2 WO 2017051198 A2 WO2017051198 A2 WO 2017051198A2 GB 2016052982 W GB2016052982 W GB 2016052982W WO 2017051198 A2 WO2017051198 A2 WO 2017051198A2
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WO
WIPO (PCT)
Prior art keywords
hull
cantilever beams
platform
skid platform
primary
Prior art date
Application number
PCT/GB2016/052982
Other languages
French (fr)
Other versions
WO2017051198A3 (en
Inventor
Iain Steven
Original Assignee
Cedeco Contractors Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cedeco Contractors Limited filed Critical Cedeco Contractors Limited
Publication of WO2017051198A2 publication Critical patent/WO2017051198A2/en
Publication of WO2017051198A3 publication Critical patent/WO2017051198A3/en

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B17/02—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto
    • E02B17/021—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto with relative movement between supporting construction and platform
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B15/00—Supports for the drilling machine, e.g. derricks or masts
    • E21B15/02—Supports for the drilling machine, e.g. derricks or masts specially adapted for underwater drilling

Definitions

  • This invention relates to jackup rigs or self-elevating units used in underwater engineering.
  • the invention is primarily applicable to rigs used in well drilling and will be described mainly in relation to such use, but is also applicable to other uses.
  • a jackup rig generally consists of a barge-like hull equipped with a number of legs (typically three or four) which can be jacked up and down relative to the hull. The legs are raised for transit to site, and then jacked down to engage the seabed to allow the rig to undertake operations such as drilling.
  • the drilling derrick and associated equipment In the case of a jackup drilling rig, it is usual for the drilling derrick and associated equipment to be mounted on a platform which is positioned inboard of the hull during transit, and is cantilevered outboard of the hull for drilling
  • the platform is moved between these two positions by a hydraulic skidding system.
  • the platform is typically a steel box structure which occupies a substantial proportion of the deck space during transit and is a large and heavy load to skid.
  • a jackup rig comprising:
  • the assembly comprising:
  • a pair of cantilever beams mounted on a deck of the hull, the beams being movable between the retracted position and the extended position, a primary skid platform mounted to the cantilever beams and movable with respect to the beams.
  • the use of an assembly which can located off the side of the hull when required incorporating cantilever beams, which can be manoeuvred to an extended position, and a platform, which can be skidded out along the beams, is much lighter than a conventional box cantilever and makes better use of deck space.
  • the cantilever beams may be slidably movable between the retracted position and the extended position
  • the assembly may further comprise a secondary skid platform mounted on the primary skid platform and movable with respect to the primary skid platform in a direction transverse to the cantilever beams.
  • the secondary skid platform may form a drill floor.
  • the primary platform incorporates well test systems, accommodation blocks, production process modules, diving systems, ROV systems and/or deconstruction and decommissioning systems.
  • the rig includes one or more movable deck modules which can be selectively positioned across the cantilever beams to form a deck between the primary skid platform and the hull when the drill floor assembly is in the extended position.
  • the deck modules may be configured to be stacked on top of each other when not in use.
  • the deck between the cantilever beams may be configured, in use, to receive shipping containers, thus making use of the space freed up by not using a box cantilever.
  • Each of the cantilever beams preferably has a height greater than a shipping container; this allows other loads to be placed across the beams above the containers.
  • the rig includes a first height adjusting mechanism for adjusting the height of the primary platform with respect to the cantilever beams.
  • the rig includes a second height adjusting mechanism for adjusting the height of the secondary platform with respect to the primary platform.
  • the height adjusting mechanism(s) may comprise a pair of opposed wedges, slidable with respect to each other, interposed between the cantilever beams and the primary skid platform or the primary skid platform and the secondary skid platform.
  • the height adjusting mechanism(s) may comprise jacks or rams interposed between the cantilever beams and the primary skid platform or the primary skid platform and the secondary skid platform.
  • the jacks or rams may be adjustable independently of each other to accommodate tilt, or both of these.
  • height adjusting mechanism allows settlement of the rig to be adjusted for, without retracting the assembly.
  • roller assemblies are provided to facilitate movement of some or all parts which slide or skid relative to each other.
  • the primary skid platform may be removable from the cantilever beams.
  • the primary skid platform may be slidably removable from the cantilever beams.
  • the primary skid platform may be configured to slide beyond the extent of the cantilever beams when the cantilever beams are in an extended
  • the primary skid platform may be skidded off the vessel on to another vessel or to allow another primary skid platform with the same or an alternative use to be skidded on the vessel.
  • a second aspect of the present invention there is provided a method of deploying a platform outboard of a jackup rig, the method comprising the steps of:
  • the step of the cantilever beams moving between the retracted position and the extended position may comprise the beams moving by sliding.
  • the method may further comprise moving a secondary skid platform mounted on the primary skid platform with respect to the primary skid platform in a direction transverse to the cantilever beams.
  • the secondary skid platform may form a drill floor.
  • the invention provides a jackup rig comprising a hull and a plurality of legs mounted for vertical movement relative to the hull, and including an assembly movable between a retracted position overlying the hull and an extended position cantilevered from the hull;
  • the assembly comprises a supporting structure and a platform movable in horizontal X and Y directions relative to the supporting structure;
  • the platform is also movable in the Z or vertical direction relative to the supporting structure.
  • the supporting structure preferably includes a pair of cantilever beams mounted on a deck of the hull for sliding movement between the retracted position and the extended position, a primary skid platform positioned across the cantilever beams and slidable along the beams after they have been extended.
  • the supporting structure may further include a secondary skid platform mounted on the primary skid platform and slidable along the primary skid platform in a direction transverse to the cantilever beams
  • the secondary skid platform may form a drill floor.
  • a still further aspect of the present invention provides a jackup rig comprising a hull and a plurality of legs mounted for vertical movement relative to the hull, and including a drill floor assembly movable between a retracted position overlying the hull and an extended position cantilevered from the hull; and in which the drill floor assembly comprises a pair of cantilever beams mounted on a deck of the hull for sliding movement between the retracted position and the extended position, a primary skid platform positioned across the cantilever beams and slidable along the beams after they have been extended, and a secondary skid platform mounted on the primary skid platform and slidable along the primary skid platform in a direction transverse to the cantilever beams, the secondary skid platform forming a drill floor.
  • Fig. 1 is a side elevation of a jackup rig forming one embodiment of the invention, with a drill floor in a retracted position;
  • Fig. 2 is a plan view at main deck level corresponding to Fig. 1 ;
  • Fig. 3 is a side elevation showing the drill floor in an extended condition
  • Fig. 4 is a plan view corresponding to Fig. 3;
  • Fig. 5 is a plan view of a modification to part of the foregoing embodiment
  • Fig. 6 is a side elevation of the parts shown in Fig. 5;
  • Fig. 7a is an underneath plan view of an upper wedge member of Figs. 5
  • Fig. 7b is a cross-sectional side view taken on the line A-A of Fig. 7a
  • Fig. 7c is a plan view of a lower wedge member of Figs. 5 and 6
  • Fig. 7d is a cross-sectional side view taken on the line B-B of Fig. 7c.
  • a jackup rig comprises a hull 10 and four legs 12 which can be jacked vertically relative to the hull 10 by rack and pinion
  • the rig is self-powered and has an accommodation block 16, but the invention is equally applicable to towed rigs and rigs without accommodation.
  • the rig has a continuous main deck 18 on which are mounted a pair of cantilever beams 20.
  • the cantilever beams 20 are arranged in spaced parallel relationship in a direction parallel to the fore-and-aft axis of the vessel, and are mounted on retractable roller assemblies 22 on which they can be moved by hydraulic rams (not shown) between a retracted position as seen in Figs. 1 and 2 and an extended position as seen in Figs. 3 and 4.
  • a primary skid platform 24 extends across the tops of the cantilever beams 20 and can be skidded longitudinally of them on retractable roller assemblies 26.
  • a secondary skid platform 28 is mounted on the primary skid platform 24 for skidding in the transverse direction.
  • the two skid platforms provide X-Y motion in a plane parallel to the man deck 18.
  • the secondary skid platform 28 acts as a work platform or drill floor on which a drilling rig may be mounted.
  • the hull 10 is formed with a moon pool 30 which passes through the main deck 18. As shown in Fig. 2, the drill floor may conveniently be positioned over the moon pool 30 when in the retracted position.
  • the configuration shown in Figs. 1 and 2 is used when the vessel is non- operational or is in transit.
  • the cantilever beams 20 are retracted and the skid platforms 24 and 28 are located well inboard of the vessel, giving good weight distribution.
  • the legs 12 are jacked down to engage the seabed and raise the hull 10 clear of the sea.
  • the cantilever beams 20 are then extended, and the primary skid platform 24 is moved outboard on the beams 20, as seen in Figs. 3 and 4.
  • the precise position of the drill floor can then be adjusted by X-Y skidding of the two skid platforms.
  • the beams 20 will be approximately 5m in height, and the cantilever when in use will extend up to 30m or more from the hull by a beam spacing of up to 18.5m.
  • a number (in this example, three) of deck modules 32 are provided. In Figs. 1 and 2, these are shown stacked on the inboard ends of the cantilever beams 20. In the working condition of Figs. 3 and 4, the deck modules 32 can be placed across the cantilever beams 20 outboard of the main deck 18 to provide a deck surface between the hull 10 and the primary skid platform 24.
  • the deck modules 32 may be of a similar construction to pontoon type hatch covers, and may be moved by skidding or by an on board crane, for example.
  • a pair of cantilever beams rather than a box structure
  • materials are stored in containers 34.
  • the containers 34 may be ISO containers, which will typically include offshore containers.
  • a modification of the above embodiment will now be described with reference to Figs. 5 to 7. This modification allows the height of the drill floor to be adjusted.
  • the X direction is defined as the longitudinal direction of the vessel and the Y direction as transverse thereto.
  • the Z direction is defined as the vertical.
  • the secondary skid platform 28 is movable in the Y direction on beams/rails 36 incorporated in the structure of the primary skid platform 24.
  • the primary skid platform 24 is carried by top flanges 20a of the cantilever beams 20 via a wedge assembly comprising upper and lower wedge members 38 and 40.
  • a hydraulic ram 42 acting in the X direction can be used to slide the wedge members relative to each other, and thus increase or decrease the vertical spacing between the cantilever beams 20 and the primary skid platform 24 to produce movement indicated at Z1.
  • the secondary skid platform 28 is mounted on the beams/rails 36 via four screw jacks 44, which can be operated to cause vertical movement indicated at Z2.
  • the screw jacks 44 can be operated independently to provide fine adjustment to provide a tilt/level function of the drill floor to accommodate small out of level conditions.
  • the screw jacks 44 may have a travel of ⁇ 250mm. This will allow for vertical and perpendicular adjustment of any mast or derrick mounted on the floor which, after commencing operation and there is settlement of the legs, ensures that vertical lift/pull at well centre can be achieved and maintained.
  • the sliding action between the wedge members 38 and 40 is facilitated by retractable roller assemblies 46, which may be for example Hillman rollers.
  • the upper and lower wedge members 38 and 40 are formed with pockets 48 and 50 for receiving the hydraulic ram 42.
  • the upper wedge member 38 is formed with a projecting key 52 which engages in a slot 54 in the lower wedge member 40
  • the lower wedge member 40 is formed with a projecting key 56 which engages in a slot 58 in the upper wedge member, thus ensuring alignment.
  • a locking arrangement (not shown) is provided between the wedge members to secure when in a desired relative position. This may be for example a ratchet arrangement with a mechanical release.
  • Removable deck sections such as shown at 60 (Fig. 5) may be added at either side of the secondary skid platform 28 to cover gaps.
  • the cantilever beams may be driven by means other than hydraulic rams, such as rack and pinion mechanisms.
  • the screw jacks in Figs. 5 and 6 could be replaced by other lift/lower means such as hydraulic rams.
  • Adjustment in the Z direction can be achieved by means other than opposed wedges; for example the primary skid platform could be mounted on screw jacks or hydraulic rams.
  • the primary skid platform may be skidded off the rig on to another vessel or on to shore.

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Abstract

A jackup rig is described. The jackup rig comprises a hull, a plurality of legs mounted for vertical movement relative to the hull, and an assembly movable between a retracted position overlying the hull and an extended position cantilevered from the hull. The assembly comprises a pair of cantilever beams mounted on a deck of the hull, the beams being movable between the retracted position and the extended position, and a primary skid platform mounted to the cantilever beams and movable with respect to the beams.

Description

IMPROVEMENTS RELATING TO JACKUP RIGS
Field
This invention relates to jackup rigs or self-elevating units used in underwater engineering. The invention is primarily applicable to rigs used in well drilling and will be described mainly in relation to such use, but is also applicable to other uses.
Background
A jackup rig generally consists of a barge-like hull equipped with a number of legs (typically three or four) which can be jacked up and down relative to the hull. The legs are raised for transit to site, and then jacked down to engage the seabed to allow the rig to undertake operations such as drilling.
In the case of a jackup drilling rig, it is usual for the drilling derrick and associated equipment to be mounted on a platform which is positioned inboard of the hull during transit, and is cantilevered outboard of the hull for drilling
operations. The platform is moved between these two positions by a hydraulic skidding system. In known rigs, the platform is typically a steel box structure which occupies a substantial proportion of the deck space during transit and is a large and heavy load to skid.
When a rig is in position and operational, it can happen that the height of the working deck above the sea requires to be adjusted, for example because of the jackup legs settling into the seabed. At present, this requires the platform to be retracted, the jackup legs adjusted, and the platform extended outboard again. Summary
Accordingly, one aspect of the present invention provides a jackup rig comprising:
a hull;
a plurality of legs mounted for vertical movement relative to the hull, and an assembly movable between a retracted position overlying the hull and an extended position cantilevered from the hull; the assembly comprising:
a pair of cantilever beams mounted on a deck of the hull, the beams being movable between the retracted position and the extended position, a primary skid platform mounted to the cantilever beams and movable with respect to the beams.
In at least one embodiment of the present invention, the use of an assembly which can located off the side of the hull when required incorporating cantilever beams, which can be manoeuvred to an extended position, and a platform, which can be skidded out along the beams, is much lighter than a conventional box cantilever and makes better use of deck space.
The cantilever beams may be slidably movable between the retracted position and the extended position
Where the terms "slide, "sliding", "slidably" and "skid" are used in this application, these are to be understood as including not only face-to-face contact but also the use of rollers or the like to reduce friction.
The assembly may further comprise a secondary skid platform mounted on the primary skid platform and movable with respect to the primary skid platform in a direction transverse to the cantilever beams.
The secondary skid platform may form a drill floor. In some embodiments the primary platform incorporates well test systems, accommodation blocks, production process modules, diving systems, ROV systems and/or deconstruction and decommissioning systems.
In some embodiments, the rig includes one or more movable deck modules which can be selectively positioned across the cantilever beams to form a deck between the primary skid platform and the hull when the drill floor assembly is in the extended position. The deck modules may be configured to be stacked on top of each other when not in use.
The deck between the cantilever beams may be configured, in use, to receive shipping containers, thus making use of the space freed up by not using a box cantilever. Each of the cantilever beams preferably has a height greater than a shipping container; this allows other loads to be placed across the beams above the containers.
In preferred forms of the invention, the rig includes a first height adjusting mechanism for adjusting the height of the primary platform with respect to the cantilever beams. In these and other embodiments, the rig includes a second height adjusting mechanism for adjusting the height of the secondary platform with respect to the primary platform.
The height adjusting mechanism(s) may comprise a pair of opposed wedges, slidable with respect to each other, interposed between the cantilever beams and the primary skid platform or the primary skid platform and the secondary skid platform.
Alternatively or additionally, the height adjusting mechanism(s) may comprise jacks or rams interposed between the cantilever beams and the primary skid platform or the primary skid platform and the secondary skid platform. The jacks or rams may be adjustable independently of each other to accommodate tilt, or both of these.
The provision of height adjusting mechanism allows settlement of the rig to be adjusted for, without retracting the assembly.
In some embodiments of the invention, roller assemblies are provided to facilitate movement of some or all parts which slide or skid relative to each other.
The primary skid platform may be removable from the cantilever beams.
The primary skid platform may be slidably removable from the cantilever beams.
The primary skid platform may be configured to slide beyond the extent of the cantilever beams when the cantilever beams are in an extended
configuration. In some embodiments the primary skid platform may be skidded off the vessel on to another vessel or to allow another primary skid platform with the same or an alternative use to be skidded on the vessel.
According to a second aspect of the present invention there is provided a method of deploying a platform outboard of a jackup rig, the method comprising the steps of:
lowering the jackup rigs legs into engagement with a seabed;
raising a jackup rig hull out of the sea;
moving a pair of cantilever beams mounted on a deck of the hull, from a retracted position overlying the hull to an extended position cantilevered from the hull,
moving a primary skid platform, mounted to the cantilever beams, along the cantilever beams to a position outboard of the rig. The step of the cantilever beams moving between the retracted position and the extended position may comprise the beams moving by sliding.
The method may further comprise moving a secondary skid platform mounted on the primary skid platform with respect to the primary skid platform in a direction transverse to the cantilever beams. In some embodiments the secondary skid platform may form a drill floor.
From another aspect, the invention provides a jackup rig comprising a hull and a plurality of legs mounted for vertical movement relative to the hull, and including an assembly movable between a retracted position overlying the hull and an extended position cantilevered from the hull;
and in which the assembly comprises a supporting structure and a platform movable in horizontal X and Y directions relative to the supporting structure;
and in which the platform is also movable in the Z or vertical direction relative to the supporting structure.
The supporting structure preferably includes a pair of cantilever beams mounted on a deck of the hull for sliding movement between the retracted position and the extended position, a primary skid platform positioned across the cantilever beams and slidable along the beams after they have been extended.
The supporting structure may further include a secondary skid platform mounted on the primary skid platform and slidable along the primary skid platform in a direction transverse to the cantilever beams
The secondary skid platform may form a drill floor.
A still further aspect of the present invention provides a jackup rig comprising a hull and a plurality of legs mounted for vertical movement relative to the hull, and including a drill floor assembly movable between a retracted position overlying the hull and an extended position cantilevered from the hull; and in which the drill floor assembly comprises a pair of cantilever beams mounted on a deck of the hull for sliding movement between the retracted position and the extended position, a primary skid platform positioned across the cantilever beams and slidable along the beams after they have been extended, and a secondary skid platform mounted on the primary skid platform and slidable along the primary skid platform in a direction transverse to the cantilever beams, the secondary skid platform forming a drill floor.
It will be understood that features listed as non-essential with respect to one aspect may be equally applicable to another aspect but have not been repeated for brevity.
Brief Description of the Drawings
Embodiments of the invention will now be described, by way of example, with reference to the drawings, in which:
Fig. 1 is a side elevation of a jackup rig forming one embodiment of the invention, with a drill floor in a retracted position;
Fig. 2 is a plan view at main deck level corresponding to Fig. 1 ;
Fig. 3 is a side elevation showing the drill floor in an extended condition;
Fig. 4 is a plan view corresponding to Fig. 3;
Fig. 5 is a plan view of a modification to part of the foregoing embodiment;
Fig. 6 is a side elevation of the parts shown in Fig. 5;
Fig. 7a is an underneath plan view of an upper wedge member of Figs. 5 Fig. 7b is a cross-sectional side view taken on the line A-A of Fig. 7a; Fig. 7c is a plan view of a lower wedge member of Figs. 5 and 6; and Fig. 7d is a cross-sectional side view taken on the line B-B of Fig. 7c. Detailed Description of the Drawings
Referring to Figs. 1 to 4, a jackup rig comprises a hull 10 and four legs 12 which can be jacked vertically relative to the hull 10 by rack and pinion
mechanisms 14. In this embodiment, the rig is self-powered and has an accommodation block 16, but the invention is equally applicable to towed rigs and rigs without accommodation.
The rig has a continuous main deck 18 on which are mounted a pair of cantilever beams 20. The cantilever beams 20 are arranged in spaced parallel relationship in a direction parallel to the fore-and-aft axis of the vessel, and are mounted on retractable roller assemblies 22 on which they can be moved by hydraulic rams (not shown) between a retracted position as seen in Figs. 1 and 2 and an extended position as seen in Figs. 3 and 4. A primary skid platform 24 extends across the tops of the cantilever beams 20 and can be skidded longitudinally of them on retractable roller assemblies 26. A secondary skid platform 28 is mounted on the primary skid platform 24 for skidding in the transverse direction. Thus, the two skid platforms provide X-Y motion in a plane parallel to the man deck 18.
The secondary skid platform 28 acts as a work platform or drill floor on which a drilling rig may be mounted.
The hull 10 is formed with a moon pool 30 which passes through the main deck 18. As shown in Fig. 2, the drill floor may conveniently be positioned over the moon pool 30 when in the retracted position.
The configuration shown in Figs. 1 and 2 is used when the vessel is non- operational or is in transit. The cantilever beams 20 are retracted and the skid platforms 24 and 28 are located well inboard of the vessel, giving good weight distribution. On arrival at a work site, the legs 12 are jacked down to engage the seabed and raise the hull 10 clear of the sea. The cantilever beams 20 are then extended, and the primary skid platform 24 is moved outboard on the beams 20, as seen in Figs. 3 and 4. The precise position of the drill floor can then be adjusted by X-Y skidding of the two skid platforms.
In a typical embodiment, the beams 20 will be approximately 5m in height, and the cantilever when in use will extend up to 30m or more from the hull by a beam spacing of up to 18.5m.
A number (in this example, three) of deck modules 32 are provided. In Figs. 1 and 2, these are shown stacked on the inboard ends of the cantilever beams 20. In the working condition of Figs. 3 and 4, the deck modules 32 can be placed across the cantilever beams 20 outboard of the main deck 18 to provide a deck surface between the hull 10 and the primary skid platform 24. The deck modules 32 may be of a similar construction to pontoon type hatch covers, and may be moved by skidding or by an on board crane, for example.
One advantage of the use of a pair of cantilever beams rather than a box structure is that a clear main deck area is maintained. This may be used for the storage of materials; in this embodiment materials are stored in containers 34. The containers 34 may be ISO containers, which will typically include offshore containers. A modification of the above embodiment will now be described with reference to Figs. 5 to 7. This modification allows the height of the drill floor to be adjusted. As before, the X direction is defined as the longitudinal direction of the vessel and the Y direction as transverse thereto. The Z direction is defined as the vertical.
Referring to Figs. 5 and 6, the secondary skid platform 28 is movable in the Y direction on beams/rails 36 incorporated in the structure of the primary skid platform 24. The primary skid platform 24 is carried by top flanges 20a of the cantilever beams 20 via a wedge assembly comprising upper and lower wedge members 38 and 40. A hydraulic ram 42 acting in the X direction can be used to slide the wedge members relative to each other, and thus increase or decrease the vertical spacing between the cantilever beams 20 and the primary skid platform 24 to produce movement indicated at Z1.
The secondary skid platform 28 is mounted on the beams/rails 36 via four screw jacks 44, which can be operated to cause vertical movement indicated at Z2. In addition, the screw jacks 44 can be operated independently to provide fine adjustment to provide a tilt/level function of the drill floor to accommodate small out of level conditions. Typically, the screw jacks 44 may have a travel of ± 250mm. This will allow for vertical and perpendicular adjustment of any mast or derrick mounted on the floor which, after commencing operation and there is settlement of the legs, ensures that vertical lift/pull at well centre can be achieved and maintained.
The wedge assembly will now be described in more detail with reference to Figs. 6 and 7a-d.
The sliding action between the wedge members 38 and 40 is facilitated by retractable roller assemblies 46, which may be for example Hillman rollers. The upper and lower wedge members 38 and 40 are formed with pockets 48 and 50 for receiving the hydraulic ram 42. The upper wedge member 38 is formed with a projecting key 52 which engages in a slot 54 in the lower wedge member 40, and the lower wedge member 40 is formed with a projecting key 56 which engages in a slot 58 in the upper wedge member, thus ensuring alignment.
A locking arrangement (not shown) is provided between the wedge members to secure when in a desired relative position. This may be for example a ratchet arrangement with a mechanical release.
Removable deck sections such as shown at 60 (Fig. 5) may be added at either side of the secondary skid platform 28 to cover gaps.
Modifications may be made to the foregoing embodiments within the scope of the invention. For example, the cantilever beams may be driven by means other than hydraulic rams, such as rack and pinion mechanisms. The screw jacks in Figs. 5 and 6 could be replaced by other lift/lower means such as hydraulic rams.
Adjustment in the Z direction can be achieved by means other than opposed wedges; for example the primary skid platform could be mounted on screw jacks or hydraulic rams.
Various modifications or improvements may be made to the above described embodiment without departing from the scope of the invention. For example, from the extended position, the primary skid platform may be skidded off the rig on to another vessel or on to shore.

Claims

Claims
1. A jackup rig comprising:
a hull;
a plurality of legs mounted for vertical movement relative to the hull, and an assembly movable between a retracted position overlying the hull and an extended position cantilevered from the hull; the assembly comprising:
a pair of cantilever beams mounted on a deck of the hull, the beams being movable between the retracted position and the extended position, and
a primary skid platform mounted to the cantilever beams and movable with respect to the beams.
2. A jackup rig according to claim 1 , wherein the cantilever beams are slidably movable between the retracted position and the extended position
3. A jackup rig according to either of claims 1 or 2, wherein the assembly further comprises a secondary skid platform mounted on the primary skid platform and movable with respect to the primary skid platform in a direction transverse to the cantilever beams.
4. A jackup rig according to claim 3, wherein the secondary skid platform forms a drill floor.
5. A jackup rig according to any preceding claim, including one or more movable deck modules which can be selectively positioned across the cantilever beams to form a deck between the primary skid platform and the hull when the drill floor assembly is in the extended position.
6. A jackup rig according to claim 5, in which there is a plurality of deck modules configured to be stacked on top of each other when not in use.
7. A jackup rig according to any preceding claim, in which the deck between the cantilever beams is adapted to receive shipping containers.
8. A jackup rig according to claim 7, in which each of the cantilever beams has a height greater than a shipping container.
9. A jackup rig according to any preceding claim, including a first adjusting mechanism for adjusting the height of the primary platform relative to the cantilever beams.
10. A jackup rig according to any preceding claim, including a second adjusting mechanism for adjusting the height of the secondary platform relative to the primary platform.
11. A jackup rig according to either of claims 9 or 10, in which the height adjusting mechanism(s) comprises a pair of opposed wedges, slidable with respect to each other, interposed between the cantilever beams and the primary skid platform or between the primary skid platform and the secondary skid platform.
12. A jackup rig according to either of claims 9 or 10, in which the height adjusting mechanism(s) comprises jacks or rams interposed between the cantilever beams and the primary skid platform or between the primary skid platform and the secondary skid platform.
13. A jackup rig according to claim 12, wherein the jacks or rams are adjustable independently of each other to accommodate tilt.
14. A jackup rig according to any preceding claim, in which retractable roller assemblies are provided to facilitate movement of some or all parts which slide or skid relative to each other.
15. A jackup rig according to any preceding claim, wherein the primary skid platform is removable from the cantilever beams.
16. A jackup rig according to claim 15, wherein the primary skid platform is slidably removable from the cantilever beams.
17. A jackup rig according to claim 16, wherein the primary skid platform is configured to slide beyond the extent of the cantilever beams when the cantilever beams are in an extended configuration.
18. A method of deploying a platform outboard of a jackup rig, the method comprising the steps of:
lowering the jackup rigs legs into engagement with a seabed;
raising a jackup rig hull out of the sea;
moving a pair of cantilever beams mounted on a deck of the hull, from a retracted position overlying the hull to an extended position cantilevered from the hull,
moving a primary skid platform, mounted to the cantilever beams, along the cantilever beams to a position outboard of the rig.
19. A method according to claim 18, wherein the cantilever beams move between the retracted position and the extended position by sliding.
20. A method according to either of claims 18 or 19, further comprising moving a secondary skid platform mounted on the primary skid platform with respect to the primary skid platform in a direction transverse to the cantilever beams.
21. A method according to claim 20, wherein the secondary skid platform forms a drill floor.
22. A jackup rig comprising a hull and a plurality of legs mounted for vertical movement relative to the hull, and including an assembly movable between a retracted position overlying the hull and an extended position cantilevered from the hull;
and in which the assembly comprises a supporting structure and a platform movable in horizontal X and Y directions relative to the supporting structure;
and in which the platform is also movable in the Z or vertical direction relative to the supporting structure.
23. A jackup rig according to claim 22, wherein the supporting structure includes a pair of cantilever beams mounted on a deck of the hull for sliding movement between the retracted position and the extended position, a primary skid platform positioned across the cantilever beams and slidable along the beams after they have been extended.
24. A jackup rig according to claim 23, wherein the supporting structure may further include a secondary skid platform mounted on the primary skid platform and slidable along the primary skid platform in a direction transverse to the cantilever beams
25. A jackup rig according to claim 24, wherein the secondary skid platform forms a drill floor.
26. A jackup rig comprising a hull and a plurality of legs mounted for vertical movement relative to the hull, and including a drill floor assembly movable between a retracted position overlying the hull and an extended position cantilevered from the hull; and in which the drill floor assembly comprises a pair of cantilever beams mounted on a deck of the hull for sliding movement between the retracted position and the extended position, a primary skid platform positioned across the cantilever beams and slidable along the beams after they have been extended, and a secondary skid platform mounted on the primary skid platform and slidable along the primary skid platform in a direction transverse to the cantilever beams, the secondary skid platform forming a drill floor.
PCT/GB2016/052982 2015-09-25 2016-09-26 Improvements relating to jackup rigs WO2017051198A2 (en)

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GBGB1516968.3A GB201516968D0 (en) 2015-09-25 2015-09-25 Improvements relating to jackup rigs

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CN113860192A (en) * 2021-09-27 2021-12-31 广东金风科技有限公司 Hoisting transportation method, transport ship and hoisting transportation equipment

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US8851797B1 (en) * 2013-03-15 2014-10-07 Offshore Technology Development Three rail multi-directional direct cantilever skidding system

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CN113863868A (en) * 2021-09-25 2021-12-31 浙江省浙南综合工程勘察测绘院有限公司 Balancing and reinforcing structure of drilling machine
CN113863868B (en) * 2021-09-25 2024-03-19 浙江省浙南综合工程勘察测绘院有限公司 Balance and reinforcement structure of drilling machine
CN113860192A (en) * 2021-09-27 2021-12-31 广东金风科技有限公司 Hoisting transportation method, transport ship and hoisting transportation equipment

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