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
• • 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
• • 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
  • E02B2017/0039—Methods for placing the offshore structure
• • 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
  • E02B2017/0056—Platforms with supporting legs
  • E02B2017/006—Platforms with supporting legs with lattice style supporting legs

Definitions

• the invention relates to an offshore system comprising a rig having a deck, and a cantilever, which is mounted on the deck and which is at least moveable in a longitudinal direction of the cantilever between a retracted position and an extended position, said cantilever having an operational end which extends beyond the deck in an extended position of the cantilever, said cantilever having an inner end opposite the operational end, said cantilever having one or more cantilever support rails in the longitudinal direction of the cantilever, the system further comprising support means comprising rail engagement members which allow longitudinal movement of the cantilever.
• a prior art offshore system having a movable cantilever is disclosed in US 6,171,027.
• This cantilever is movable both in longitudinal direction (X-direction) and in transverse direction (Y-direction) , basically along the side of the deck.
• An advantage of such a system is that the loads on the cantilever apply in the centre. Because the cantilever can be loaded efficiently its weight can be reduced and the capacity can be enhanced.
• Another advantage is that at the operational end a tower, and hence the drilling line, can be located in the middle of the cantilever giving the possibility to create an enclosed area with a moonpool in the centre.
• a drawback of the known offshore systems having a cantilever with (borehole) equipment at the operational end is the limited size of the Mrilling envelope', i.e. the area that can be reached with (borehole) equipment by moving the cantilever in the longitudinal direction, and possibly also in a second (non-longitudinal) direction.
• the cantilever projects partly beyond the deck of the rig.
• the cantilever In the retracted position the cantilever is mainly situated on the deck of the rig.
• the size of the cantilever that can be used is determined by the space available on deck. In some cases, the available space for movement and storage of the cantilever is limited, e.g. when the rig is a jack-up platform. Then one or more the legs of the jack-up from an obstacle. The same goes for any other "obstacle" on deck, such as accommodation for crew, machinery, cranes, etc.
• the aim of the invention is to enlarge the ⁇ envelope' of a cantilever type offshore system.
• the system further comprises a support rail extension part for each cantilever support rail, that allows to extend the cantilever support rail at the inner end of the cantilever by being positioned in line with the cantilever support rail, for the purpose of increasing the length of the cantilever support rail and thereby the longitudinal reach of the cantilever.
• the inventive system allows that the cantilever can be further extended in length by the support rail extension parts, thereby allowing a further movement in the longitudinal direction and enlarging the envelope in this dimension.
• support rail extension parts are removed or moved to a storage position.
• the support rail extension parts can be stored in the cantilever and move out of the cantilever telescopically when required, or the support rail extension parts can be slided in line with the cantilever support rail.
• the support rail extension parts can for example be stored on the deck of the rig, in the cantilever or on another rig.
• the support rail extension parts can also be positioned in line with the cantilever support rail by the aid of a crane.
• the cantilever is a box structure.
• Various equipment can be installed inside the cantilever. This facilitates the interface between the deck and the cantilever.
• the support rail extension part is a separate part that is mountable on the cantilever.
• the support rail extension part can e.g. be stored on deck, in the cantilever, suspended or hung on a side of the cantilever or stored on another ship.
• the support rail extension part is hingedly mounted on the cantilever or otherwise movably arranged on the cantilever, e.g. movable between a storage position and an active position.
• the support rail extension part could be arranged telescopically .
• the support rail extension part is designed as a flap, preferably a flap that is connected hingedly to the cantilever, e.g. about a vertical hinge axis, preferably near the inner end of the cantilever .
• bearing means are provided between the rail engagement members on the support means and the cantilever support rails on the cantilever.
• the cantilever support rails comprise or form a longitudinal bearing surface or sliding surface or a rail surface- forming head.
• the support means are mounted moveable on the deck, so that the cantilever is also moveable in a second (non- longitudinal) direction, while the cantilever is supported by the support means for movement in the longitudinal direction.
• the cantilever is also moveable in a translational direction perpendicular to the first longitudinal movement, in this case, a rectangular drilling envelope can be obtained.
• the second direction in which the cantilever can move is a rotational movement.
• the support means is connectable or connected to the rig so that the cantilever is rotatable about a rotating axis, e.g. by a rotation pin.
• the rotating axis could be made positionable at multiple positions with respect to the rig, e.g. displaceable along a guide member. It is also possible to provide rails on the deck which allow for a movement of the support means, which rails could be made of an annular or circular shape which allows for a rotational movement of the support means.
• the cantilever is mounted so that it can be rotated at least between 0 and 90 degrees or is at least moveable in two directions or both.
• the cantilever with the tower can be arranged movable in two directions by extending the cantilever in its longitudinal direction and rotating the support means about a rotation axis on the rig.
• the shape of a thus- obtained drilling envelope is a segment of a ring.
• friction reducing bearing means are provided at suitable locations. For instance at least two bearing members that are movable over the deck or a rail located closest to the edge of the rig are provided, which bearing members are operative in the longitudinal direction as well as in the transverse direction, to take up at least a part of the frictional forces between the support means and the relevant deck area and between the bottom plate area of the cantilever and the support means.
• the friction-reducing bearing means are formed by hydrostatic bearings. It is contemplated that one or more mud pumps present on the rigs can be used to feed pressurized fluid, such as (sea) water to the hydrostatic bearings avoiding the need for separate power packs for this purpose. Alternatively, and even more practical, is the use of roller assemblies as bearing means.
• the support means comprise a frame arranged between the deck and the cantilever, e.g. an essentially rectangular frame.
• the bearing means between one or more rails mounted on the deck and the frame of the support means are disposed at multiple positions, e.g. at all corners of said frame .
• borehole equipment is provided at the operational end of the cantilever.
• the borehole equipment may comprise any suitable equipment for effecting activities related to a borehole or associated operations in the oil and gas industry. These include for instance drilling tools, maintenance tools or well intervention tools, lifting equipment for lowering or retrieving subsea equipment, such as wellhead equipment, etc.
• a tower or derrick and/ or crane is provided at the operational end of the cantilever.
• a multi-purpose tower is mounted on the cantilever.
• the multi-purpose tower e.g. can comprise drilling equipment, lifting equipment, etc.
• a drill floor can be provided on a top deck of the cantilever.
• the length of the cantilever is between 30- 60 metres, wherein the rails can be extended with at least 5 metres, preferably at least 10m possibly up to 60m by the support rail extension parts.
• a particular preferred surface area of the drill floor on the cantilever is ⁇ 200m 2 .
• the rig can be a member of the group: a Compliant Tower, a Deep Draft Caisson vessel, a SPAR, a Tension Leg Platform, Temporary Tension Leg Platform, a Semi Submersible rig, Jack-Up platform and Mono Hull Ship.
• figs. 1-5 indicate subsequent stages of a method of installing drilling equipment on a sub-sea well using a preferred embodiment of a offshore system according to the invention; figs. 6-10 show details of the flaps of the offshore system shown in figs. 1-5.
• a rig 1 having a deck 2.
• the rig 1 in this embodiment is a Jack-up platform comprising jack houses 3a, in which the legs 3b of the jack-up are moveable.
• a cantilever 4 is mounted on the deck of the rig 2.
• a borehole equipment 5 in this embodiment a tower 5, is fixedly attached to the cantilever 4.
• a piperacker 8a is placed beside the tower 5, as well as a pipehandler 8b and pipe storage 8c.
• a gantry crane 9 is placed on the cantilever 4.
• Cantilever 4 is mounted on deck 2 via support means 7.
• the cantilever 4 comprises cantilever support rails 10 in longitudinal direction L of the cantilever 4.
• Support rails 10 comprise a longitudinal bearing surface (not shown) .
• Support means 7 comprise rail engagement members 7a, which allow longitudinal movement of the cantilever 4.
• Bearing means can be positioned between the longitudinal bearing surface of the support rails 10 and the rail engagement members 7a.
• a circular shaped rail 11 is mounted on deck 2 which allows for a rotational movement of the support means 7, so that the cantilever 4 is rotatable.
• Friction reducing bearing means are provided between the rails 11 mounted on the deck 2 and the support means 7.
• the cantilever 4 In the rest position shown in fig. 1, the cantilever 4 is in its retracted position, situated on the deck 2 of the drilling rig 1.
• cantilever 4 has partly moved in its longitudinal direction to an extended position. In this position, the tower 5 comprising borehole equipment extends beyond the deck 2 of the jack up platform 1, capable of performing operations in this area.
• two hinges 6a are provided to which support rail extension parts 6b' are connected.
• the support rail extension parts 6b' comprise two foldable flaps 6b.
• the hinges 6a extend perpendicular to the longitudinal direction 4a of the cantilever 4.
• a beam 6c is provided between flaps 6b for reasons of stability.
• the flaps 6b were folded in to the end of the cantilever 4 remote from the tower 5, perpendicular to the longitudinal direction L of the cantilever 4.
• the cantilever 4 has moved further in the longitudinal direction to a further extended position than shown in fig. 2.
• the position of the cantilever is extended even further than the furthest position possible solely with the cantilever 4, by the aid of the support rail extension parts 6b.
• the cantilever 4 is also shown in its furthest extended position, in which the cantilever 4 has also rotated with respect to deck 2.
• a detail of deck 2 and cantilever 4 is shown, which cantilever 4 has moved into a longitudinal direction of the cantilever, indicated with the character ⁇ L' , to an almost fully extended position of the cantilever 4 itself.
• the operational end of the cantilever is not shown in this figure.
• Cantilever 4 is mounted on deck 2 via support means 7.
• the cantilever 4 comprises cantilever support rails 10 in the longitudinal direction L of the cantilever 4.
• Support rails 10 comprise a longitudinal bearing surface (not shown) .
• Support means 7 comprise rail engagement members 7a, which allow longitudinal movement of the cantilever 4.
• Support rail extension parts 6b' are connected to the inner end 4b of the cantilever 4 by hinges 6a.
• Support rail extension parts 6b' comprise flaps 6b.
• Rail engagement members 7a on support means 7 allow longitudinal movement of the cantilever 4, but also of the extension parts 6b' .
• a circular shaped rail 11 is mounted on deck 2 which allows for a rotational movement of the support means 7, so that the cantilever 4 is rotatable .
• Friction reducing bearing means (not shown) are provided between the rails 11 mounted on the deck 2 and the support means 7. In figs. 6-10, the support rail extension parts 6b' are shown in subsequent positions, between the positions shown in fig. 2 and 3.
• the flaps 6b are partly folded out, being hinged about hinges 6a. In fig. 8, the flaps 6b are fully folded out, such that the rail extension parts 6b' are positioned in line with the cantilever support rail 10.
• the rail extension parts 6b' can move across rail engagement members 7a of support means 7, allowing for a longitudinal movement of the rail extension parts 6b' .
• the length of the cantilever support rail 10 has increased by the length of the support rail extension parts 6b' , thereby increasing the longitudinal reach to the cantilever 4. Therefore, it is possible for the cantilever 4 to move to a position extended further than the fully extended position of the cantilever solely.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Structural Engineering (AREA)
• Civil Engineering (AREA)
• Geology (AREA)
• Mining & Mineral Resources (AREA)
• Physics & Mathematics (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Earth Drilling (AREA)

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• 2005
  • 2005-10-11 WO PCT/NL2005/000733 patent/WO2007043856A1/en active Application Filing
  • 2005-10-11 CN CN200580051819XA patent/CN101316966B/zh not_active Expired - Fee Related
  • 2005-10-11 US US12/083,291 patent/US20080298898A1/en not_active Abandoned
  • 2005-10-11 EP EP05791858A patent/EP1934403A1/en not_active Withdrawn

Non-Patent Citations (1)

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