WO1999043921A1 - Procede et dispositif destines au transfert de superstructures de plates-formes marines d'une sous-structure fixee au fond de la mer a un transporteur flottant - Google Patents

Procede et dispositif destines au transfert de superstructures de plates-formes marines d'une sous-structure fixee au fond de la mer a un transporteur flottant Download PDF

Info

Publication number
WO1999043921A1
WO1999043921A1 PCT/NO1999/000064 NO9900064W WO9943921A1 WO 1999043921 A1 WO1999043921 A1 WO 1999043921A1 NO 9900064 W NO9900064 W NO 9900064W WO 9943921 A1 WO9943921 A1 WO 9943921A1
Authority
WO
WIPO (PCT)
Prior art keywords
transporter
topsides
substructure
beams
recess
Prior art date
Application number
PCT/NO1999/000064
Other languages
English (en)
Norwegian (no)
Inventor
Per Bull HAUGSØEN
Gunnar Foss
Original Assignee
Marine Shuttle Operations As
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 Marine Shuttle Operations As filed Critical Marine Shuttle Operations As
Priority to AU31756/99A priority Critical patent/AU3175699A/en
Publication of WO1999043921A1 publication Critical patent/WO1999043921A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
    • B63B35/003—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for for transporting very large loads, e.g. offshore structure modules
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F13/00—Units comprising springs of the non-fluid type as well as vibration-dampers, shock-absorbers, or fluid springs
    • F16F13/04—Units comprising springs of the non-fluid type as well as vibration-dampers, shock-absorbers, or fluid springs comprising both a plastics spring and a damper, e.g. a friction damper
    • F16F13/06—Units comprising springs of the non-fluid type as well as vibration-dampers, shock-absorbers, or fluid springs comprising both a plastics spring and a damper, e.g. a friction damper the damper being a fluid damper, e.g. the plastics spring not forming a part of the wall of the fluid chamber of the damper
    • F16F13/08—Units comprising springs of the non-fluid type as well as vibration-dampers, shock-absorbers, or fluid springs comprising both a plastics spring and a damper, e.g. a friction damper the damper being a fluid damper, e.g. the plastics spring not forming a part of the wall of the fluid chamber of the damper the plastics spring forming at least a part of the wall of the fluid chamber of the damper
    • 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
    • E02B2017/0052—Removal or dismantling of offshore structures from their offshore location

Definitions

  • the invention relates to a method and a device for transfer of an offshore platform topsides from a substructure fixed to the seabed to a floating transporter.
  • Norwegian patent no. 160 424 describes a devices which is composed of two parallel groups of floats. Each group comprises a horizontal float to which vertical floats are attached at one of their ends, while their other ends are attached to longitudinal beams. The end of one group is connected to the end of the other by two horizontal, longitudinal floats and a box beam. The longitudinal beams bear movable support beams which can be moved in under the cargo which has to be lifted and transported.
  • GB 2 165 188 A describes a vessel for installation and removal of a deck module on to or from a platform substructure.
  • the vessel is U-shaped with an opening where the platform substructure is located, and comprises a system of movable pillars on each side of the opening for support and positioning of the module.
  • Norwegian patent application no. 973562 describes a transporter for removal of an offshore platform topsides from an associated substructure, which transporter consists of an oblong, ballastable structure with a U-shaped cross section and a prismatic enveloping surface, and comprises two long sides, an intermediate underside and an opposing open top. At one end of the underside there is a recess which can accommodate the substructure when the transporter is located with the underside horizontally down in the water, and on the side of the recess the long sides have abutment portions which, when the transporter is deballasted, can be brought into abutment against the platform topsides and lift it, thus transferring it to the transporter.
  • a common problem when transferring objects at sea is impacts due to the movement of the sea.
  • the substructure When transferring an offshore platform topsides from a substructure fixed to the seabed to a floating transporter, the substructure will substantially be at rest, while the transporter will move dependent on the movement of the sea.
  • the transporter When the transporter is located close to the topsides and is in the process of being connected thereto, its movement will be capable of causing jarring impacts to occur between the transporter and the topsides, which, if no allowance is made for them, will be capable of damaging both the transporter and the topsides.
  • a similar problem exists after the topsides has been secured to the transporter and is in the process of being released from the substructure, when, due to movement caused by the transporter, the topsides might collide with the substructure.
  • a further problem which is manifested in all offshore structures is oscillations generated in the structure due to wave action.
  • all offshore structures must be designed on the basis that their natural frequency must be outside the range of the waves' excitation frequency.
  • the transporter After attachment of the transporter to the topsides as described in Norwegian patent application no. 973562, on account of the rigidity of the attachment to the topsides, the transporter will obtain a completely different natural frequency to that which it had before attachment. If this is not taken into account, the transporter may begin to oscillate due to excitation from the waves, which may bring it out of control, resulting in jarring impacts between the transporter and the topsides.
  • the transfer of an offshore platform topsides from a substructure fixed to the seabed to a floating transporter as described in the above-mentioned publications is not without its problems.
  • the object of the invention is to provide methods and devices for transfer of an offshore platform topsides from a substructure fixed to the seabed to a floating transporter, which methods and devices should not be encumbered by the above-mentioned problems.
  • fig. 1 is a perspective view of a transporter which is located in the water beside an offshore installation fixed to the seabed.
  • Fig. 2 is a curve illustrating the problem of oscillations of the transporter due to the wave action.
  • Figs. 3-6 illustrate a transporter provided with beams according to the invention during various stages of transfer of a platform topsides to the transporter according to the invention.
  • Fig. 7 illustrates lifting beams and fenders for use in the transfer of the platform topsides.
  • Fig. 8 illustrates the lifting beams in a position where they can lift the topsides.
  • Fig. 9 illustrates a lifting beam in closer detail.
  • Fig. 10 illustrates a friction clamp for use in the transfer of the platform topsides.
  • Figs. 1 1-13 illustrate the juxtaposition of the lifting beam, the friction clamp and a cut platform leg during the transfer of the platform topsides.
  • Fig. 14 illustrates a pair of lifting beams which together form a uniform lifting beam for lifting the friction clamp.
  • Fig. 15 illustrates the lifting beam and the friction clamp after the platform leg which has been cut below has been released from the friction clamp.
  • Fig. 1 illustrates a floating transporter 1 which is located in the water beside an offshore structure consisting of a platform topsides 3 resting on a substructure 2 which is located on the seabed 6.
  • the transporter consists of an underside 25 and a long side 24 arranged on each side of the underside, the three sides thereby forming an oblong structure with a U-shaped cross section.
  • the transporter is shown in a deballasted position where its underside is located on the surface of the sea 5, and the figure illustrates how the end of the underside which is facing the platform topsides, hereinafter called the front end, has a recess 26.
  • the outermost part of the recess, which is located at the end of the transporter, is called the recess's opening 27.
  • the transporter On transfer of the topsides 3 from the substructure 2 to the transporter 1, the transporter is lowered by means of ballasting. The front end of the transporter is then introduced under the platform topsides, the substructure thereby entering the recess's opening 27, and subsequently the actual recess 26, while at the same time the long sides 24 remain under/beside the topsides 3. The transporter 1 is then deballasted, thus causing it to be raised and lifting the topsides 3 from the substructure 2, whereupon the transporter with the topsides are removed from the substructure.
  • Fig. 2 shows a curve illustrating the problem mentioned at the beginning of oscillations of the transporter due to excitation from the wave action.
  • the curve shows amplitude x for the transporter's horizontal oscillations after attachment to the topsides as a function of the horizontal rigidity k in the attachment.
  • Fig. 2 gives typical values for a transporter and a large topsides for a platform in the North Sea.
  • Wave action is a highly complicated phenomenon, with different amplitudes, directions and frequencies. Analyses show that the excitation from the waves on the transporter which has the greatest significance has a period of round 8 seconds, designated first order movement. First order movement has relatively little amplitude, but great forces are required to suppress it. The excitation with the second greatest significance has a period of round 100 seconds, and is designated second order movement. Second order movement has large amplitude, but can be suppressed with relatively small forces. Further excitations also have an influence on the transporter, but are of minor significance.
  • the amplitude has a low value at 0 rigidity, i.e. no attachment to the topsides.
  • the transporter's amplitude here corresponds substantially to first order movement.
  • the preferred operational area for attachment is area C.
  • the oscillatory movements may also be counteracted with damping devices which absorb the oscillatory movement by means of friction, as well as reducing their velocity.
  • damping devices can be established by mooring the transporter to the seabed with oscillation-damping moorings in the form of chains or wires. It is also possible to establish a cross between a rigidity and a damping attachment by using such moorings between the transporter and the topsides, or between the transporter and the substructure.
  • a substantial part of the transporter's oscillatory movement has to be established by a rigidity in the actual attachment of the transporter to the topsides, since otherwise the topsides might work loose from the transporter.
  • Fig. 3 illustrates a transporter provided with devices according to the invention, ballasted in such a manner that it is located with the underside 25 down in the water, and the long sides 24 projecting up from the surface 5 of the sea.
  • the transporter At a level above the surface, on the illustrated embodiment near the top of the long sides 24, the transporter comprises a front cross beam 28 which extends between the transporter's long sides 24.
  • the front cross beam 28 is located over the recess's opening 27, but since the underside 25 with the recess 26 are located under water, the recess's opening is not illustrated in fig. 3.
  • fig. 1 shows the position of the recess's opening 27.
  • the transporter further comprises two rear cross beams 33 which extend between the long sides 24 on the opposite side of the recess 26 relative to the recess's opening 27.
  • the front cross beam 28 and the rear cross beams 33 rest on brackets or mountings 35 and 36 respectively attached to the long sides 24.
  • the transporter further comprises longitudinal beams 30, 30' which are supported by the cross beams 28, 33.
  • the longitudinal beams 30, 30' are arranged in pairs at intervals which are slightly larger than the diameter of the substructure's legs, and are bounded between longitudinal openings 29 for insertion of the substructure's legs, which will be described in more detail 7
  • Fig. 3 also illustrates lifting beams 31, 31', which will be described in more detail with reference to fig. 7 and beyond.
  • Fig. 4 illustrates the front cross beam 28 in a position where, before the actual transfer of the topsides, it is not located over the recess's opening, thus providing access to the area over the recess 26.
  • This is achieved by having the front cross beam movably mounted in its longitudinal direction P i in one of the mountings 35 in one of the long sides 24.
  • this lateral movement of the front cross beam 28 is only one of several possible ways of opening access to the area over the recess 26, and this can also be achieved by attaching one end of the front cross beam 28 to the mounting 35 by a rotating joint, or lifting away the front cross beam with a crane, which may, for example, be located on an auxiliary vessel or the platform topsides.
  • the longitudinal beams are supported only by the rear cross beams 33, which due to the weight of the longitudinal beams will be exposed to a moment.
  • This is an important reason for having two rear cross beams 33, since the moment is thereby absorbed as a force couple, but of course it is also possible to employ other designs of the rear cross beams, such as a torsionally rigid beam which is capable of absorbing the moment.
  • the platform topsides and the platform substructure may be designed in a number of different ways, which are of no importance for the invention.
  • a common design of the substructure involves a substructure which is composed of tubular legs, at least in an upper portion which is connected to the topsides. Before the actual transfer of the topsides according to the invention these tubular legs are cut and a clamp is affixed which temporarily secures the topsides to the substructure and holds together the cut surfaces through the legs.
  • These clamps may be of different types, and may have different types of remote control for release. In one type which may be employed securing is 8
  • the transporter After access has been provided to the area over the recess as described with reference to fig. 4, the transporter is moved in under the platform topsides in a known per se manner.
  • Fig. 5 illustrates the transporter after it has been moved in under the platform topsides.
  • the long sides 24 are located on the outside of the substructure, with the result that the substructure is located in the recess 26 (see fig. 1).
  • the actual topsides is not shown, and the substructure and the recess are located under water, with the result that the only part of the substructure which can be seen is the upper portions of the substructure's legs, indicated by reference numeral 4, with the clamps affixed for temporary securing, indicated by reference numeral 7.
  • the transporter is steered in such a manner that the legs 4 enter the two longitudinal openings 29, as mentioned with reference to fig.
  • the width of the longitudinal openings 29 being slightly larger than the diameter of the legs 4.
  • the front cross beam 28 is then moved back to its original position over the recess's opening 27, which is illustrated in fig. 6. In this position the front cross beam 28 supports the longitudinal beams 30, 30', and since as mentioned the longitudinal beams are also supported by the rear cross beams 33, full support is obtained of the longitudinal beams at both ends.
  • Fig. 7 illustrates fenders 32 which are arranged on sides of the longitudinal beams 30, 30' facing the longitudinal openings 29. These fenders are moved into abutment against the substructure's legs 4, thereby achieving damping of the transporter's 1 horizontal movement in the longitudinal openings' transverse direction P2-
  • the distance between the fenders 32 in the longitudinal openings 29 is less than the diameter of the substructure's legs 4. This results in tight control and immediate damping of the transporter's movement in the transverse direction P2, while at the same time leading to a damping of the transporter's horizontal movement in the longitudinal openings' longitudinal direction P3.
  • the lifting beams 31, 31' are moved to the position illustrated in fig. 8.
  • the design of the lifting beams must be so adapted to the topsides that they are capable of lifting it.
  • the transporter is then raised by means of deballasting, and the lifting beams 31 , 31' are brought into engagement with the topsides 3.
  • the transporter 1 is further deballasted to a buoyancy which exceeds the weight of the topsides 3, and the clamps 7 for temporary securing of the topsides 3 to the substructure 2 are released, thus causing the topsides to be lifted up from the substructure.
  • the clamp 7 will hereinafter be described as a friction clamp.
  • other types of clamps for temporary securing of the topsides to the substructure such as clamps which are screwed directly into the legs on the top and underside of the cuts 9, as illustrated in figs. 10-13.
  • Fig. 9 illustrates an embodiment of a lifting beam 31 which is provided with a vertical recess 34 which corresponds to the shape of the leg 4 to which a clamp 7 is affixed.
  • the lifting beam's attachment to the longitudinal beams which, for example, may be composed of horizontal contact surfaces and vertical borings in the lifting beam with corresponding bolts in the longitudinal beams, in order to provide horizontal rotatability and lateral securing, is not shown.
  • a corresponding pair-forming not shown opposing lifting beam 31' has a corresponding vertical recess, and by moving the two lifting beams 31 , 31' to a position in which they extend over the longitudinal openings 29, simultaneously being located adjacent to the leg 4 with the two recesses facing each other, the object is achieved that the pair of lifting beams 31, 31' forms a uniform double lifting beam which encircles the leg 4.
  • This double lifting beam is illustrated in fig. 14. 10
  • the lifting beam 31 in fig. 9 further comprises horizontally acting spring devices 16 securely attached to the vertical recess 34, and a horizontal sliding surface 17 arranged on the top of the lifting beam, on the side of the vertical recesses 34.
  • the sliding surface 17 is adapted to abut against the topsides 3 to receive the weight of the topsides, while at the same time the topsides is permitted to move in the horizontal direction.
  • the sliding surface 17 may, for example, consist of teflon or an oil film.
  • Fig. 10 illustrates a section through a friction clamp 7 for holding the leg temporarily together after it has been cut. Together with the friction clamp there is shown a leg 4, which has been cut through at 9.
  • the friction clamp 7 comprises a friction portion 8 which is adapted to be clamped round the leg 4 and abuts against the leg along a length 1 of the leg.
  • the friction clamp's clamping effect is achieved by the fact that the friction portion 8 comprises one or more longitudinal slots, which are located in the section surface in fig. 10, and horizontal screws 37 placed in a row along the leg, across the slots, which when tightened reduce the slot opening, thereby clamping the friction portion 8 against the leg 4.
  • the screws or other tightening devices may be remotely controlled, for example by means of hydraulics.
  • the clamping of the friction portions 8 round the leg is preferably different, i.e. variably adjustably along the length 1 of the leg 4, thus enabling the friction clamp to be adapted to the desired frictional force on the top 10 and the underside 11 of the cut 9.
  • the friction clamp further comprises a lifting portion 14 adapted to abut against the transporter's lifting beams for lifting the friction clamp with the leg in the vertical direction.
  • the friction clamp also comprises a vertically acting spring device 15, attached on the underside of the lifting portion 14, to receive vertical forces from vertical movement of the transporter during connection thereto.
  • Fig. 11 illustrates a section through an intersected leg 4 with a friction clamp 7, encircled by a lifting beam 31. It should be understood that a corresponding, not shown lifting beam 31' encircles the rest of the leg and the friction clamp, with the result that the lifting beams' horizontal sliding surface 17 is located under the whole underside of the vertically acting spring 11
  • Fig. 12 illustrates the position during the initial stage of deballasting of the transporter, where the lifting beams' horizontal sliding surfaces 17 are raised to such an extent that they have come into abutment against the underside of the vertically acting spring devices 15. Due to vertical oscillatory movement of the transporter, which in turn is due to the wave action, the horizontal sliding surfaces 17 move vertically up and down, colliding against the vertically acting spring devices 15. These shocks are absorbed by the vertically acting spring devices, without causing damage.
  • Fig. 13 illustrates the position during further deballasting of the transporter.
  • the transporter's vertical oscillatory movement here does not give rise to impacts, but instead is absorbed as variations in the compression of the vertically acting spring devices.
  • deballasting of the transporter increases the weight of the topsides is gradually transferred from the substructure to the transporter, and the forces between the friction clamps' lifting portions 14 and the lifting beams 31, 31' gradually become so great that the transporter remains almost at rest in the vertical direction.
  • the problem of impacts between the transporter and the topsides when the transporter is in the process of being brought into abutment against the topsides is thereby solved.
  • Fig. 14 illustrates a pair of lifting beams 31, 31' which together encircle the leg 4 with the friction clamp 14, forming a uniform lifting beam for lifting the friction clamp.
  • the vertically acting spring devices are compressed and fig. 14 thus shows the same relative position between the lifting beam, the friction clamp and the leg as in fig. 13.
  • the transporter's horizontal movement can be absorbed in several ways.
  • the oscillatory movement can be absorbed by means of damping devices which absorb the oscillatory movements with friction, but that in order to prevent the topsides from working loose from the transporter it is necessary to establish a rigidity in the actual securing means.
  • Horizontal damping movement can be achieved by providing a horizontally acting oscillation damper between the topsides 3 and the transporter 1.
  • an oscillation damper of this kind may comprise double-acting hydraulic cylinders where the cylinders' two sides communicate with each other via a choke valve.
  • Horizontal damping movement can also be achieved by giving the horizontal sliding surface 17 a certain amount of preselected friction. This can be done as simply as having two steel surfaces slide against each other, but may also be done by applying to the surfaces a coating intended for this purpose. A part of the oscillatory movement can thereby be absorbed by frictional forces. However, it is necessary to restrict these frictional forces in order to avoid inducing excessive horizontal forces on the vertically acting spring devices, as mentioned above.
  • a horizontal rigidity can be obtained by arranging a horizontally acting spring device between the topsides 3 and the transporter 1. This is achieved by means of the said horizontally acting spring devices 16 arranged in the vertical recesses 34 in the lifting beams 31, 31'.
  • the lifting beams are caused in pairs to encircle the legs 4 with the friction clamps 7, the horizontally acting spring devices are brought into abutment against the friction clamps. Since the friction clamps are securely connected to the legs 4, in reality the horizontally acting spring devices are brought into abutment against the legs, thereby damping the transporter's horizontal movement.
  • the transporter may also be moored to the seabed, or also to the topsides or the substructure. In an actual case a combination of several of these functions may be employed in order to dampen the transporter's oscillatory movement. 13
  • the horizontally acting spring devices are securely connected to the lifting beams in their vertical recesses, and abut loosely against the legs with the friction clamps. From the above, however, it should be evident that in order to provide the horizontal rigidity between the transporter and the legs or the topsides, it is unimportant where the horizontally acting spring devices are attached, and that they therefore might just as well have been attached to the friction clamps and abutted loosely against the lifting beams in their vertical recesses.
  • Both the vertically acting spring devices and the horizontally acting spring devices preferably have a progressive characteristic.
  • An advantageous embodiment is obtained by constructing the spring devices from alternately arranged lamellae of a rigid material, in practice steel, and an elastomer, usually rubber.
  • the steel lamellae are indicated by reference numerals 18 and 20 for the vertically acting and horizontally acting spring devices respectively, while the corresponding elastomer lamellae are indicated by reference numerals 19 and 21.
  • the vertically acting spring devices 15 are designed as rings which are located along the circumference of the friction clamps' lifting portions 14, and are composed of lamellae with the surfaces parallel to the ring's radial direction.
  • the horizontally acting spring devices 16 are designed as rings which encircle the legs 4, and are composed of lamellae which form concentric rings around the legs 4.
  • the horizontally acting spring devices thereby provide a radial spring effect for the leg 4 in all horizontal directions.
  • Both the vertically and horizontally acting spring devices could, however, have been designed in other ways, for example as groups of separate blocks composed of lamellae of steel and an elastomer. 14
  • the springing properties are taken care of by the elastomer lamellae, while the steel lamellae counteract lateral protuberance of the elastomer lamellae.
  • the object is achieved that the attachment of the transporter to the topsides is carried out with a rigidity in the area which with reference to fig. 2 is indicated by C, and the problem of oscillations of the transporter after attachment to the topsides due to excitation from the waves can thereby be solved.
  • the friction clamps' total frictional force below the cuts is arranged to be greater than or equal to the buoyancy required by the transporter 1 in order to lift the topsides 3 to a height where the risk of collision between opposing cut surfaces in the cut 9 due to the vertical movement obtained by the transporter 1 and the topsides 3 after the topsides is released from the substructure and attached to the transporter is not present.
  • the transporter and the topsides will obtain a vertical oscillatory movement which is hydrodynamically dampened by the surrounding water.
  • the frictional force between the friction clamps and the legs below the cuts must be so great that the topsides does not work loose before the transporter's buoyancy is so great that the transporter and the topsides will not move downwards to such an extent that the cut surfaces on the top of the cuts collide with the cut surfaces on the underside of the cuts.
  • This frictional force can be calculated by an analysis of the transporter's buoyancy and dynamic behaviour in the water.
  • the transporter After the transporter has been deballasted to such an extent that it is almost at rest against the friction clamps' lifting portions, as mentioned with reference to figs. 13 and 14, the transporter is further deballasted to a buoyancy which exceeds the weight of the topsides.
  • the transporter's buoyancy is equal to the sum of the weight of the topsides 3 and the frictional force between the friction clamps 7 and the legs 4 on the underside 11 of the cuts 9, the friction clamps on the underside of the cuts are released, thereby causing the topsides to be lifted up from the substructure, which is given by an equation of equilibrium.
  • the cut surfaces on the top of the cuts are prevented from colliding with the cut surfaces on the underside of the cuts after the topsides has been released from the substructure.
  • the problem of collisions between the topsides and the substructure when the topsides is in the process of being released from the substructure is thereby solved.
  • the frictional forces should be provided in rather larger amounts than necessary both above and below the cuts, and that the frictional force between portions of the legs 4 below the cuts 9 and corresponding portions of the friction portions 8 should be reduced after the transporter has been given the buoyancy required for the friction portions to be released.
  • Fig. 15 illustrates the lifting beam 31 and the friction clamp with the lifting portion 14 and the friction portion 8 after the platform leg is released from the friction clamp on the underside 1 1 of the cut.
  • the cut surface on the top 10 of the cut is indicated here by reference numeral 12, while the cut surface on the underside 11 of the cut is indicated by reference numeral 13.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Transportation (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Ocean & Marine Engineering (AREA)
  • Earth Drilling (AREA)

Abstract

L'invention concerne un procédé permettant de transférer des superstructures (3) de plates-formes marines d'une sous-structure (2) fixée au fond marin à un transporteur (1) flottant, procédé dans lequel le transporteur (1) est abaissé par ballastage, puis déplacé sous les superstructures (3) de la plate-forme, le transporteur étant ensuite déballesté, ce qui le fait remonter et soulève ainsi les superstructures à partir de la sous-structure. A cet effet, le transporteur (1) comprend une structure oblongue que l'on peut ballaster, constituée de deux côtés (24) longs et d'un évidement (26) intermédiaire présentant une ouverture (27) dans l'une des extrémités du transporteur et pouvant renfermer la sous-structure (2) lorsque le transporteur (1) se trouve dans une position où l'évidement (26) est horizontalement submergé. On utilise une traverse (28) avant s'étendant entre les côtés (24) longs au-dessus de l'ouverture (27) de l'évidement, des barrots (30, 30') longitudinaux qui sont fixés au transporteur (1) au-dessus de l'évidement (26), et des palonniers (31, 31') de levage des superstructures (3), supportés par les barrots (30, 30') longitudinaux.
PCT/NO1999/000064 1998-02-26 1999-02-25 Procede et dispositif destines au transfert de superstructures de plates-formes marines d'une sous-structure fixee au fond de la mer a un transporteur flottant WO1999043921A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU31756/99A AU3175699A (en) 1998-02-26 1999-02-25 Method and device for transferring of an offshore platform topsides from a seabed fixed substructure to a floating transporter

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO980824A NO307293B1 (no) 1998-02-26 1998-02-26 Bjelker til bruk ved fremgangsmåte og anordning til bruk ved overfoering av et offshore plattformdekk fra et bunnfast understell til en flytende transportoer
NO19980824 1998-02-26

Publications (1)

Publication Number Publication Date
WO1999043921A1 true WO1999043921A1 (fr) 1999-09-02

Family

ID=19901725

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NO1999/000064 WO1999043921A1 (fr) 1998-02-26 1999-02-25 Procede et dispositif destines au transfert de superstructures de plates-formes marines d'une sous-structure fixee au fond de la mer a un transporteur flottant

Country Status (3)

Country Link
AU (1) AU3175699A (fr)
NO (1) NO307293B1 (fr)
WO (1) WO1999043921A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001053609A1 (fr) * 2000-01-17 2001-07-26 Saipem U.K. Limited Demontage des ponts de constructions en mer
US10046405B2 (en) 2014-11-26 2018-08-14 Quanta Associates, L.P. Salvage sawing system and method
US10786855B2 (en) 2012-12-28 2020-09-29 1 Diamond, Llc Sawing system, sawing support structure and a wire replacement unit and method
US11339549B2 (en) 2018-01-30 2022-05-24 Quanta Associates, L.P. Inclined cut GBS leg

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2907172A (en) * 1955-09-19 1959-10-06 Shell Dev Method and apparatus for constructing offshore drilling platforms
US5403124A (en) * 1993-07-26 1995-04-04 Mcdermott International, Inc. Semisubmersible vessel for transporting and installing heavy deck sections offshore using quick drop ballast system
WO1998026979A1 (fr) * 1996-12-18 1998-06-25 Offshore Shuttle As Dispositif de transport d'objets lourds en mer
WO1999006271A1 (fr) * 1997-08-01 1999-02-11 Marine Shuttle Operations As Transporteur permettant d'installer ou d'enlever une plate-forme de forage marine et procede permettant d'enlever une plate-forme de forage marine
WO1999006270A1 (fr) * 1997-08-01 1999-02-11 Marine Shuttle Operations As Procede et transporteur pour l'installation et le retrait d'oeuvres mortes de plates-formes de forage en mer

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2907172A (en) * 1955-09-19 1959-10-06 Shell Dev Method and apparatus for constructing offshore drilling platforms
US5403124A (en) * 1993-07-26 1995-04-04 Mcdermott International, Inc. Semisubmersible vessel for transporting and installing heavy deck sections offshore using quick drop ballast system
WO1998026979A1 (fr) * 1996-12-18 1998-06-25 Offshore Shuttle As Dispositif de transport d'objets lourds en mer
WO1999006271A1 (fr) * 1997-08-01 1999-02-11 Marine Shuttle Operations As Transporteur permettant d'installer ou d'enlever une plate-forme de forage marine et procede permettant d'enlever une plate-forme de forage marine
WO1999006270A1 (fr) * 1997-08-01 1999-02-11 Marine Shuttle Operations As Procede et transporteur pour l'installation et le retrait d'oeuvres mortes de plates-formes de forage en mer

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001053609A1 (fr) * 2000-01-17 2001-07-26 Saipem U.K. Limited Demontage des ponts de constructions en mer
US6736571B2 (en) 2000-01-17 2004-05-18 Saipem U.K. Limited Removal of decks from offshore structures
AU781045B2 (en) * 2000-01-17 2005-05-05 Saipem Limited Removal of decks from offshore structures
US10786855B2 (en) 2012-12-28 2020-09-29 1 Diamond, Llc Sawing system, sawing support structure and a wire replacement unit and method
US10046405B2 (en) 2014-11-26 2018-08-14 Quanta Associates, L.P. Salvage sawing system and method
US11339549B2 (en) 2018-01-30 2022-05-24 Quanta Associates, L.P. Inclined cut GBS leg

Also Published As

Publication number Publication date
AU3175699A (en) 1999-09-15
NO980824L (no) 1999-08-27
NO307293B1 (no) 2000-03-13
NO980824D0 (no) 1998-02-26

Similar Documents

Publication Publication Date Title
US4744697A (en) Installation and removal vessel
US4979453A (en) Floating dock system
KR101341763B1 (ko) 쌍동선 시스템의 상부 구조물과 격자에 관한 부하를 줄이고 강철을 절약하는 재하공법 및 쌍동선 시스템
US4655641A (en) Apparatus for aligning a platform deck and jacket
GB2165188A (en) Installation and removal vessel
US3937170A (en) Bumper guard and arrangement for water covered areas
WO1998026979A1 (fr) Dispositif de transport d'objets lourds en mer
WO1999043921A1 (fr) Procede et dispositif destines au transfert de superstructures de plates-formes marines d'une sous-structure fixee au fond de la mer a un transporteur flottant
WO1999006270A1 (fr) Procede et transporteur pour l'installation et le retrait d'oeuvres mortes de plates-formes de forage en mer
WO1999043543A1 (fr) Surface coulissante destinee au transfert de superstructures de plates-formes marines d'une sous-structure a un transporteur flottant
AU719838B2 (en) Transportation system and installation method
WO1999043542A1 (fr) Collier de friction pour transferer une superstructure de plate-forme de forage d'une infrastructure a un transporteur flottant
KR102309460B1 (ko) 항만 플랜트 및 항만 플랜트에 플로팅 바디를 계류시키기 위한 방법
CA1284919C (fr) Ensemble a plate-forme flottante
US6648553B2 (en) Load transfer unit and method for removing off-shore platform from substructure
JPS61155509A (ja) 大型海洋構造物の据付方法
GB2174743A (en) Module installation and removal system
CA1140401A (fr) Quais lateraux cantilever pour quai flottant
US20020108551A1 (en) Fender assembly and method for locating a substructure or barge in a moonpool of a ballastable transporter
SU1576657A1 (ru) Устройство дл морского монтажа верхнего строени стационарной морской платформы на опорное основание
KR200234681Y1 (ko) 중량물 거치를 위한 압소바시스템
EP0192311A2 (fr) Procédé pour poser une plate-forme sur une structure de support entourée d'eau, spécialement dans les mers houleuses et bateau pour la mise en oeuvre de ce procédé
JP2004276637A (ja) 浮体の係留装置
GB2084228A (en) Mine lifting apparatus
JPS58204333A (ja) 試験水槽

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AL AM AT AU AZ BA BB BG BR BY CA CH CN CU CZ DE DK EE ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT UA UG US UZ VN YU ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH GM KE LS MW SD SL SZ UG ZW AM AZ BY KG KZ MD RU TJ TM AT BE CH CY DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA GN GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
NENP Non-entry into the national phase

Ref country code: KR

REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase