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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
  • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
  • B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
  • B63B21/50—Anchoring arrangements or methods for special vessels, e.g. for floating drilling platforms or dredgers
• • 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
  • E02B17/04—Equipment specially adapted for raising, lowering, or immobilising the working platform relative to the supporting construction
  • E02B17/08—Equipment specially adapted for raising, lowering, or immobilising the working platform relative to the supporting construction for raising or lowering
  • E02B17/0818—Equipment specially adapted for raising, lowering, or immobilising the working platform relative to the supporting construction for raising or lowering with racks actuated by pinions
• • 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
• • 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
  • E02B2017/0073—Details of sea bottom engaging footing
  • E02B2017/0078—Suction piles, suction cans

Definitions

• Offshore operating platform and installation processes at an offshore operation site of such a platform are possible.
• the present invention relates to an offshore operating platform, as well as methods of installation on a site of operation of such a platform.
• Offshore platforms of the self-elevating type such as oil rigs, generally include legs, including three in number, resting on the seabed, and a movable bridge mounted and adjustable in height along the legs and including operating equipment and living quarters.
• each leg is equipped with a foot or a base to bear on the seabed when the platform is installed on a site of exploitation.
• This foot or base of each leg has a contact surface with the seabed which is limited to support the weight of the platform that under calm sea conditions and for a relatively short time.
• the legs of the platform must be firmly anchored in the seabed.
• this arrangement poses problems when assembling the boxes on the lower end of the legs of the platform. Indeed, the lower end of each leg is submerged in most cases so that the handling of these boxes requires a heavy infrastructure and complex because of the volumes to manage because these boxes have a diameter of about 17 to 20 meters and a height that can reach several meters.
• the invention aims to remedy these drawbacks by proposing an offshore operating platform whose installation cost on a marine site is reduced.
• the invention therefore relates to an offshore operating platform, of the type comprising a movably mounted bridge on legs each having, at its lower part, a support base on the seabed and a box open at its base and intended to penetrate into the seabed to anchor the platform, characterized in that each box is disposed inside a leg and is movable in the axis of this leg between a retracted high position and a position low protruding from the base of the leg and anchored in the seabed and in that the box has locking means on the leg in the lower position of said box.
• the distance separating the abutments and the base of the leg is less than the height of the casing of this leg
• each box comprise: at least two opposite arms, mounted on the lower end of the box and extending above said box,
• the arms are inclined towards the outside of the box and movable between this inclined position and a substantially vertical position during the translation of the box.
• the subject of the invention is also a method of installation on an offshore exploitation site of a platform, characterized in that it consists of the following steps: - to bring the platform by flotation or on a barge on the site, the caisson of each leg being in the high retracted position,
• the invention also relates to another method of installation on an offshore exploitation site of a petroleum platform, characterized in that it consists of the following steps: - to bring the platform by flotation or on a barge on the site, the caisson of each leg being in high retracted position,
• FIG. 1 is a diagrammatic elevational view of an offshore operating platform, in accordance with the invention, and in a floating position,
• FIG. 2 is a schematic cross-sectional view of a leg of the platform and taken along line 2-2 of FIG. 1,
• FIG. 3 is a schematic view in elevation and on a larger scale of the lower part of a leg of the platform, according to the invention
• FIG. 4 is a schematic perspective view of an anchoring box of a leg of the platform, according to the invention.
• FIG. 5 is a schematic perspective view of the lower part of a chord of a leg of the platform, according to the invention.
• the bridge 1 is movably mounted on vertical legs 2 which each have a triangular section, as shown in FIG. 2. These legs 2 may also have a square or circular section and they may be three or four, evenly distributed on the bridge 1.
• the displacement of the bridge 1 on the legs 2 is effected by means of drive mechanisms, not shown, housed for each leg, in a supporting frame 5 also called by the "jack-house” specialists.
• Each supporting frame 5 is supported by the bridge 1 and the drive mechanisms are formed, in a conventional manner by geared motor assemblies each driving an output pinion cooperating with racks 6 disposed on the frames 3 of each leg 2, and as shown in FIG. 2.
• These legs 2 are intended to bear on the seabed 7 (FIGS.6 and 7) when the platform is in the drilling or operating position and, for this purpose, each leg 2 ends, at its lower part, by a base 8.
• each leg 2 comprises, at its lower part, a box 10 open at its base and which is intended to penetrate into the seabed 7 to a desired depth so as to anchor the corresponding leg 2 in this seabed, as we will see later.
• each leg 2 is disposed inside the corresponding leg 2 and is movable in the axis of this leg 2 between a raised retracted position (Figs 1 and 3) in which only the lower end 10a of this box 10 protrudes below the base 8 of the leg 2 and a low protruding position ( Figure 7) in which only the upper end 10b of this box 10 is disposed in the leg 2.
• each leg 2 comprise at least one support member on the corresponding box 10 in the upper position of this box 10 so as to prevent the rise of said box during the application of the lower end of this leg 2 on the seabed 7 and each box 10 has locking means on the corresponding leg 2 in its lower position so as to block the box 10 in the lower anchoring position of the corresponding leg 2 on the seabed 7.
• each support member on the casing 10 in each leg 2 is constituted by a horizontal abutment stop 20 and fixed on a chord 3 inside the leg 2 above the upper end 10b of the box 10 in its retracted high position (FIG 3).
• the distance between the bearing stops 20 and the base 8 of the leg 2 is less than the height of the box 10 of the leg 2 so as to maintain the lower part 10a of the box 10 below the base 8 in the up position. retracted from this box 10.
• the box 10 has a cross section conjugate to the cross section of the leg 2 and, in this case, a triangular cross section.
• the locking means of the box 10 comprise an arm 25 for each frame 3 of the leg 2 and mounted on the upper end 10b of the box 10, as shown in FIG. 4.
• the arms 25 extend above the box 10 and are inclined towards the outside of this box 10.
• each arm 25 has a first end 25a hingedly mounted on the box 10 and a second end 25b said free end which is provided with two opposite pins 26 extending transversely to the longitudinal axis of the arm 25.
• Each arm 25 is movable between this inclined position in which the end 25b is held pressed against a frame 3 of the leg 2 and a substantially vertical position during the translation of the box 10 between the retracted high position and the low protruding position, as will be described later.
• each arm 25 is provided for example by a jack 27, such as for example a hydraulic cylinder, pneumatic or electric, disposed on the upper face of the box 10.
• the movement of each arm 25 can be provided by any other body appropriate and of known type, such as for example an elastic member holding the corresponding arm 25 in its inclined position towards the outside of the box 10.
• each arm 25 may have a shape suitable for this arm is inclined outwards the box in its normal position and an elastic portion holding the arm in this position.
• the locking means of the box 10 in the low projecting position also comprise a bottom stop 30 (FIGS 3 and 5) fixed on each frame 3, disposed inside and at the lower end of each frame 3 of a leg. 2.
• These stops 30 are intended to cooperate each with a stop 31 disposed at the upper end of the box 10 in the lower position of the box 10.
• each upper lateral edge of the stops 30 is equipped with a flange 30a forming with the opposite flange 30a a space 32 extending upwards and in the shape of a V (FIG.5) for guiding the stop 31 corresponding.
• each box 10 comprises an intermediate stop 35 fixed on each frame 3, disposed inside the leg 2 above the lower stops 30.
• Each stop 35 is constituted, as shown in FIG. 5, two parallel elements 35a and forming between them a V-shaped space 36 for guiding and the passage of a stop 31 during the descent of the box 10.
• each box 10 comprise at least two opposite arms 25, at least two opposite lower stops 30 and at least two intermediate stops 35 also opposed.
• these elements 25, 30 and 35 are preferably three in number each and in the case of a leg 2 with a square section, said elements 25, 30 and 35 are preferably in number of four each.
• the installation of the platform on an operating site is carried out as follows.
• the platform is brought to the site by floatation or on a barge.
• the legs 2 of the platform are in the raised position and the box 10 of each leg 2 is in the raised position retracted into the corresponding leg 2.
• Each box 10 is held in this position for example by applying the ends 25b of the arms 25 to the ribs 3 of the legs 2 by means of the cylinders 27 or by any other appropriate means, such as for example a chain connecting the box 10 to the bridge 1 of the platform.
• the legs 2 When the platform is on the operating site, the legs 2 are gradually lowered by means of the drive mechanisms carried by the bridge 1 and which act on the racks 6 of the chords 3 of said legs 2. These legs 2 are progressively down to the application of the bases 8 on the seabed 7, as shown in FIG. 6. During the descent of each leg 2, the bearing stops 20 of the leg 2 are in contact with the box 10 so as to penetrate the lower portion 10a of the box 10 in the seabed 7.
• the next step is to anchor the legs 2 in the seabed 7 by means of the boxes 10.
• the anchoring of a box 10 we will describe the anchoring of a box 10, the anchoring of the other boxes 10 being identical.
• the pressure inside the box 10 is reduced by means of the pumping unit associated with the box 10 so as to cause a progressive descent of the box 10 which enters the seabed 7.
• the arms 25 are tilted by the cylinders 27 substantially in vertical position so as to allow these arms 25 to pass between the bearing abutments 20 and between the intermediate stops 35.
• deck 1 of the platform can be raised before the caissons 10 are driven into the seabed 7.
• the stops 30 and 31 which are in contact in the anchoring position of the legs 2 by the box 10 allow, in the case where the legs 2 are raised, these boxes 10 to follow the movement.
• the platform according to the invention has the advantage, thanks to the retractable anchoring boxes in the legs, to have a reduced draft during its transport on a site of exploitation compared to the platforms of this type used so far.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Combustion & Propulsion (AREA)
• Chemical & Material Sciences (AREA)
• Ocean & Marine Engineering (AREA)
• Earth Drilling (AREA)
• Revetment (AREA)
• Bridges Or Land Bridges (AREA)
• Foundations (AREA)
• Filling Or Discharging Of Gas Storage Vessels (AREA)

Applications Claiming Priority (2)

Publications (2)

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ID=34949456

Family Applications (1)

Country Status (11)

Families Citing this family (2)

Family Cites Families (7)

• 2004
  • 2004-10-06 FR FR0410545A patent/FR2876124B1/fr not_active Expired - Fee Related
• 2005
  • 2005-09-26 KR KR1020077006413A patent/KR101338570B1/ko not_active IP Right Cessation
  • 2005-09-26 WO PCT/FR2005/002379 patent/WO2006037871A1/fr active Application Filing
  • 2005-09-26 MX MX2007003811A patent/MX2007003811A/es active IP Right Grant
  • 2005-09-26 DK DK05804232.6T patent/DK1797245T3/en active
  • 2005-09-26 EA EA200700812A patent/EA009612B1/ru not_active IP Right Cessation
  • 2005-09-26 AU AU2005291133A patent/AU2005291133B2/en not_active Ceased
  • 2005-09-26 ES ES05804232.6T patent/ES2530276T3/es active Active
  • 2005-09-26 EP EP05804232.6A patent/EP1797245B1/de not_active Not-in-force
  • 2005-09-26 US US11/576,630 patent/US7690866B2/en active Active
• 2007
  • 2007-03-27 NO NO20071588A patent/NO20071588L/no not_active Application Discontinuation

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