EP0045653B1 - Ancrage d'une structure flottante - Google Patents

Ancrage d'une structure flottante Download PDF

Info

Publication number
EP0045653B1
EP0045653B1 EP19810303541 EP81303541A EP0045653B1 EP 0045653 B1 EP0045653 B1 EP 0045653B1 EP 19810303541 EP19810303541 EP 19810303541 EP 81303541 A EP81303541 A EP 81303541A EP 0045653 B1 EP0045653 B1 EP 0045653B1
Authority
EP
European Patent Office
Prior art keywords
mooring lines
temporary mooring
floating structure
lines
temporary
Prior art date
Legal status (The legal status 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 status listed.)
Expired
Application number
EP19810303541
Other languages
German (de)
English (en)
Other versions
EP0045653A1 (fr
Inventor
Riley Gene Goldsmith
John Allen Mercier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ConocoPhillips Co
Original Assignee
Conoco Inc
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
Priority claimed from US06/175,101 external-priority patent/US4352599A/en
Priority claimed from US06/180,767 external-priority patent/US4354446A/en
Application filed by Conoco Inc filed Critical Conoco Inc
Publication of EP0045653A1 publication Critical patent/EP0045653A1/fr
Application granted granted Critical
Publication of EP0045653B1 publication Critical patent/EP0045653B1/fr
Expired legal-status Critical Current

Links

Images

Classifications

    • 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
    • B63B21/502—Anchoring arrangements or methods for special vessels, e.g. for floating drilling platforms or dredgers by means of tension legs
    • 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
    • E21B41/00—Equipment or details not covered by groups E21B15/00 - E21B40/00
    • E21B41/0007—Equipment or details not covered by groups E21B15/00 - E21B40/00 for underwater installations
    • E21B41/0014—Underwater well locating or reentry systems
    • 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
    • E21B41/00—Equipment or details not covered by groups E21B15/00 - E21B40/00
    • E21B41/10—Guide posts, e.g. releasable; Attaching guide lines to underwater guide bases

Definitions

  • This invention relates generally to the mooring of floating structures, and more particularly, but not by way of limitation, to the mooring of a floating structure utilized as an offshore oil and gas drilling and production platform.
  • tension leg platform One particular problem which must be overcome with any design of tension leg platform is the manner in which the floating platform is attached to the subsea anchor, i.e. the manner of mooring. Particularly, when locating the platform in deep waters where severe environmental conditions are often present, such as for example in the North Sea, it is desirable that the actual mooring of the platform be accomplished in a relatively short time, e.g. a matter of hours, and that it be accomplished without the need for the use of divers.
  • Both of the openings 82 and 41 of Blenkarn et al. include upwardly opening funnel shaped portions.
  • the platform of Blenkarn et al. is moved into place with tug boats. After the risers are connected, the temporary mooring cables are released.
  • UK Patent No. 2035935 discloses a temporary mooring arrangement wherein temporary lines extend in a catenary between the floating structure and anchors set by tugs at positions spaced around the structure.
  • the structure is not restricted from vertical movement and may therefore roll or sway with the wind and waves which is undesirable.
  • the invention provides a method of temporarily mooring a floating structure, said method including the step of providing a plurality of temporary mooring lines which extend between said floating structure and anchor means positioned on a floor of a body of water, said temporary mooring lines having first ends thereof connected to said anchor means.
  • a method is known from GB-A-2035935.
  • the invention provides a temporary mooring apparatus for a floating structure, comprising anchor means positioned on a floor of a body of water, and a plurality of temporary mooring lines having first ends attached to said anchor means adapted to extend between the structure and the anchor means, (GB-A-2035935) characterised by a plurality of pendant lines connected to second ends of said temporary mooring lines, retrieval means attached to said floating structure for retrieving said plurality of pendant lines and a portion of each of said temporary mooring lines onto said floating structure until said floating structure is located approximately at a position directly above said anchor means, and tension means for tensioning said plurality of temporary mooring lines so that a tension load on each of said temporary mooring lines is greater than a magnitude of cyclic forces exerted on each of said temporary mooring lines.
  • mooring of the structure may be achieved relatively quickly and moreover the arrangement is such that the structure is restrained from moving vertically.
  • a plurality of temporary mooring lines are connected to a corresponding plurality of anchor assemblies.
  • a plurality of pendant lines including marker buoys are connected to the temporary mooring lines and are laid on the ocean floor and arranged in a spread pattern.
  • the tension leg platform is provided with a plurality of retrieving winches which are connected to the pendant lines to retrieve the pendant lines and a portion of each of the temporary mooring lines onto the floating structure until the tension leg platform is located approximately at a position directly above the anchors. Then the temporary mooring lines are tensioned to temporarily moor the tension leg platform. While the tension leg platform is temporarily moored, the permanent vertical tethering elements are connected between the tension leg platform and the anchor means by lowering those permanent tethering elements into engagement with connector means attached to the anchors. Guide funnels are attached to the anchors above the connector means for guiding the lower ends of the permanent tethering elements into engagement with the connector means.
  • Other preferred embodiments and methods of the invention are set out in the dependent claims.
  • a tension leg platform which may be referred to as a floating structure, is generally designated by the numeral 10.
  • the tension leg platform 10 is shown floating on a surface 12 of a body of water 14, and is temporarily moored to a floor 16 of the body of water 14 by a plurality of temporary mooring lines 18 connected to a plurality of separate anchor assemblies 20.
  • the tension leg platform 10 includes a work deck 22 supported by a buoyant structure including vertical column members 24 and horizontal pontoon members 26.
  • auxiliary derrick 28 Located above each of the four corner columns 24 is an auxiliary derrick 28 which provides a means for lowering permanent tethering elements, such as the one designated by the numeral 30 in Fig. 1, through the corner columns 24. It will be understood that Fig. 1 is schematic only and that there are four auxiliary derricks 28, one located above each of the corner columns 24.
  • main derrick 32 Also located upon work deck 22 is main derrick 32 which provides a means for performing drilling and production operations.
  • FIG. 2 a plan view is thereshown of four anchor assemblies 20 located upon the ocean floor 16 in a predetermined pattern relative to a drilling template 34.
  • the drilling template 34 and anchor assemblies 20 are positioned upon the ocean floor 16 prior to the use of the apparatus and method of the present invention for temporarily mooring the tension leg platform 10 to those anchors 20.
  • Fig. 2 shows four temporary mooring lines 18, each of which has its first end 36 connected to one of the anchor assemblies 20.
  • the temporary mooring lines are laid in a spread pattern upon the ocean floor 16.
  • spread pattern it is meant that each of the temporary mooring lines 18 extends outward from its anchor assembly 20 so that second ends 38 of the temporary mooring lines 18 are spaced from each other.
  • a plurality of pendant lines 40 are connected to the second ends 38 of the temporary mooring lines 18.
  • Fig. 3 illustrates one of the temporary mooring lines 18, with a pendant line 40 attached thereto, being laid upon the ocean floor 16 by second floating structure 44 which is preferably a conventional drilling ship or the like.
  • the temporary mooring lines 18' may be attached to the pendant lines 40 prior to the lowering of the temporary mooring lines 18 from the drilling ship 44 and prior to the attachment of the lower ends 36 of temporary mooring lines 18 to the anchor means 20.
  • the temporary mooring lines 18 are preferably constructed from four or five-inch link chain having a conventional hydraulic actuated well head connector 46 attached to a lower end thereof.
  • the well head connector 46 is actuated by a hydraulic signal transmitted by means of hydraulic lines 48.
  • the anchor assembly 20 includes a standard well head type connection 50 for attachment to the well head connector 46.
  • the temporary mooring line 18 is lowered by means of a drill string 52 from the drilling ship 44.
  • the drill string 52 has a cage 54 attached to a lower end thereof, which cage includes a bracket means 56 for supporting the lower end 36 of temporary mooring line 18.
  • Cage 54 has an underwater television camera 58 disposed therein for observing the connection of temporary mooring line 18 to the anchor assembly 20.
  • Fig. 10 illustrates the temporary mooring line 18 attached to the anchor assembly 20.
  • the tension leg platform 10 is moved to a position sufficiently close to a position directly above anchor means 20 so that the pendant lines 40 may be connected to the tension leg platform 10. Then the pendant lines 40 are attached to a plurality of retrieval means 60 which are located upon the tension leg platform 10.
  • the retrieval means 60 preferably includes four separate winches 60.
  • Each of the winches 60 includes a conventional drum portion for winding one of pendant lines 40 thereon, and a conventional windlass portion for retrieving one of the mooring lines 18.
  • a chain locker is located below the windlass for receiving the mooring line 18 which is a link chain.
  • corner column members 24 Of the vertical column members 24 of tension leg platform 10, there are four of the vertical column members located at the corners of work deck 22 which may be referred to as corner column members 24. Each of those corner column members includes three hause pipes 62 which extend vertically therethrough so that a permanent tethering element 30 may be lowered through each of the hause pipes 62.
  • the pendant lines 40 are placed through one of the hause pipes 62 of each of the corner columns 24 and the pendant lines 40 are then attached to the winches 60.
  • FIG. 4 may be considered to show either the pendant lines 40 or the temporary mooring lines 18 attached to each of the winches 60, and this is indicated by the use of double designations 40, 18 on each of the lines attached to the winches 60.
  • the winches 60 are actuated to retrieve the pendant lines, 40 and a portion of each of the temporary mooring lines 18 onto the winches 60 of the tension leg platform 10 until the tension leg platform 10 is located approximately at a position directly above the anchor means 20, such as is shown in Fig. 1.
  • the temporary mooring lines 18 are tensioned so that a tension load on each of said temporary mooring lines 18 is greater than a magnitude of cyclic forces exerted on each of said temporary mooring lines 18, thereby preventing any snap loads on the temporary mooring lines 18 which would otherwise occur upon the temporary mooring lines 18 becoming slack.
  • the connecting of the temporary mooring lines 18 to anchor means 20, connecting of pendant lines 40 to temporary mooring lines 18, and connecting of pendant lines 40 to retrieval means 60 may be accomplished without the second vessel 44, although the method described above using second vessel 44 is preferred.
  • a temporary mooring line 18 could be lowered from the main derrick 32 of platform 10 into engagement with anchor means 20. Then, while the temporary mooring line 18 is supported from main derrick 32, one of the pendant lines 40 could be lowered from one of the auxiliary derricks 28 through one of the hause pipes 62, and its lower end could be attached to the mooring line 18 at connection 38. Then the temporary mooring line 18 is released from main derrick 32, and the pendant line 40 and temporary mooring line 18 are retrieved through the hause pipe 62 on one of the winch means 60.
  • the tensioning of the temporary mooring lines 18 may be accomplished in several different ways.
  • a heave compensator 64 engaged with each of the temporary mooring lines 18.
  • Such a heave compensator 64 is shown schematically in Fig. 5 and the position of the heave compensator 64 is also illustrated in Fig. 1.
  • the heave compensator 64 includes a hydraulic cylinder 66 having a piston 68 reciprocably disposed therein.
  • a rod 70 is attached to piston 68 and has a guide sheave 72 rotatingly attached thereto.
  • the temporary mooring line 18 engages guide sheave 72.
  • a constant hydraulic pressure is applied to a lower surface 74 of piston 66 from a pressure chamber 76 defined within cylinder 66 below piston 68. Constant pressure hydraulic fluid is supplied to the chamber 76 through a conduit 78 from a pressure transfer cylinder 80.
  • pressure transfer cylinder 80 Disposed within pressure transfer cylinder 80 is a floating piston 82 which divides pressure transfer cylinder 80 into a hydraulic fluid chamber 84 and a primary pressure chamber 86.
  • the primary pressure chamber 86 is connected to a pressure source 88 by conduit 90 which has a pressure regulator 92 disposed therein.
  • the pressure source 88 is preferably a source of gas under pressure
  • the pressure regulator 92 provides a means for regulating the pressure of the gas within the primary pressure chamber 86 of pressure transfer cylinder 80.
  • the pressure of the gas within primary pressure chamber 86 is transmitted to the hydraulic fluid in hydraulic pressure chamber 84 by the floating piston 82.
  • This provides a means for applying a constant hydraulic pressure to the piston 68 of cylinder 66 of heave compensator 64, and for varying that constant hydraulic pressure to increase or decrease the same to correspondingly increase or decrease the tension applied to the temporary mooring line 18 by the heave compensator 64.
  • Another method of tensioning the temporary mooring lines 18 is to lock each of the temporary mooring lines 18 to the tension leg platform 10 with a conventional chainstopper (not shown) to fix the length thereof, and then to deballast the tension leg platform 10 in a manner well known to those skilled in the art, to increase the buoyancy thereof and thereby increase the tension applied to the temporary mooring lines 18.
  • Yet another manner of tensioning the temporary mooring lines 18 is to construct the winches 60 of sufficient capacity so that they may apply the desired tension to the temporary mooring lines 18.
  • a solution to this problem is provided by applying a horizontal force to the tension leg platform 10 to move it horizontally away from the position directly above the anchor means 20 by a distance sufficient to apply a temporary tension load to each of the temporary mooring lines 18 great enough to-.prevent snap loads from being imposed upon the temporary mooring lines 18 due to the cyclical forces of the waves acting upon the tension leg platform 10.
  • This horizontal force is preferably applied to the tension leg platform 10 by the use of a conventional tug boat.
  • the temporary mooring lines 18 may be permanently tensioned in one of the three manners described above, or in a similar manner, while the horizontal force is maintained upon the tension leg platform 10 by the tug boat. In that manner the permanent tensioning can be accomplished without allowing any snap loads to be applied to the temporary mooring lines 18 during the permanent tensioning.
  • Fig. 6 illustrates schematically the forces acting upon tension leg platform 10 when a horizontal force H is applied thereto.
  • a tugboat 93 is schematically illustrated as applying the force H.
  • Horizontal forces may also be present due to tides, wide currents and the like.
  • the non-displaced position of the tension leg platform 10 is shown in phantom lines, and the displaced position of tension leg platform 10 is shown in solid lines, with the platform 10 displaced through a distance X due to the horizontal force H represented by the vector 94.
  • Table 1 was prepared from the following analysis of the forces illustrated in Fig. 6. By summing the horizontal and vertical forces acting upon the tension leg platform 10, the following equations 1 and 2, respectively, are obtained.
  • the angle by which the temporary mooring lines 18 are displaced from a vertical position is represented by the symbol a.
  • the excess buoyancy To is the weight of water displaced by the tension leg platform 10 in excess of the weight of the tension leg platform 10.
  • the water plane area, Awp is the horizontal area of the tension leg platform 10 at an imaginary horizontal section therethrough at the surface 12 of the body of water 14.
  • the specific weight of sea water is represented by the symbol y.
  • the forces listed in Tables 1 and 2 are in metric tonnes.
  • Fig. 7 schematically represents the forces acting upon tension leg platform 10 when the temporary mooring lines 18 are ten feet longer than the desired length. This illustrates the horizontal forces required to pre-tension the temporary mooring lines 18 when the tension leg platform 10 is initially located approximately above the anchor means 20, but not exactly directly above the anchor means 20. It will be understood that the analysis and discussion with regard to Fig. 7 is merely by way of example to illustrate the forces required to pre-tension the temporary mooring lines 18 with a less than perfect initial positioning of the platform 10. These figures are given because it is very possible that the initial positioning of the tension leg platform 10 prior to the permanent tension of the temporary mooring lines 18 will be such that there will be some slight initial offset.
  • the initial offset required to straighten the temporary mooring lines 18 is represented by the designation X o and is obtained in the following manner:
  • the initial angle of the temporary mooring lines 18 from the vertical is designated as a o .
  • the numbers from Tables 1 and 2 illustrate the horizontal force H required to achieve a given horizontal displacement X in feet as shown in the left hand column of the tables, for a given excess buoyancy T a listed in the top row of each table.
  • the pre-tension force T in the temporary mooring lines 18 corresponding to the horizontal displacement X may be determined by the relationships given with regard to Figs. 6 and 7.
  • the corresponding offset X may be determined from Equation 2 for Fig. 6 and Equation 4 for Fig. 7, and the known relationship between X and a. That value of X may be used to enter Table 1 or 2, and depending upon the value of To for the specific platform under consideration the value of H is shown in the tables.
  • the tension leg platform 10 may be permanently moored by attaching a plurality of permanent vertical mooring elements, such as 30, between the tension leg platform 10 and the anchors 20 while the tension leg platform 10 is temporarily moored. This is preferably accomplished in the following manner.
  • the following method is particularly useful with a plurality of separate anchor assemblies 20 as disclosed herein, because it provides a means for maneuvering the permanent tethering elements 30 as they are lowered into engagement with the anchor assemblies 20. This is desirable because of inherent inaccuracies in the positioning of the anchor assemblies 20 upon the ocean floor 16.
  • FIG. 8 a plan view is thereshown of one of the anchor assemblies 20.
  • the anchor assembly 20 includes three separate connector means 100, 102 and 104, for connecting three of the permanent tethering elements 30 to the anchor 20.
  • Each of the guide means 106, 108 and 110 are provided with label indicia means 112, 114 and 116, respectively, so that a proper one of said guide funnels to be engaged by a given one of the permanent vertical tethering elements 30 may be determined by visually observing the guide funnels.
  • the indicia means 112 of guide funnel 106 includes the number 1 and a single stripe encircling the connector means 100.
  • indicia means 114 includes the numeral 2 and two stripes.
  • the permanent vertical tethering elements 30 are lowered from the tension leg platform 10, as is shown in Figs. 1 and 10, until a lower end 118 of the tethering element 30 is located a relatively short distance above the anchor means 20.
  • An underwater television camera is then used to observe the location of the lower end 118 of permanent vertical tethering element 30 relative to the appropriate one of the guide funnels above the appropriate connector means to which it is to be attached. For example, referring to Fig. 10, if the tethering element 30 thereshown is desired to be connected to the connector 102, the tethering element 30 should be located above the guide funnel 108.
  • Fig. 1 illustrates a remote controlled vehicle 120 which is connected to the tension leg platform 10 by a command cable 122 and within which is disposed a television camera 124.
  • the location of the remote control vehicle 120 within the body of water 114 is controlled by a plurality of thrusting propellers such as 126 which operate in response to signals conveyed down the cable 122.
  • FIG. 12 An alternative is shown in Fig. 12, where a television camera 128 is disposed in an inner passageway 129 of the permanent vertical tethering element 30 so that the television camera 128 looks downward below the tethering element 30.
  • the camera 128 may be retrieved after the tethering element 30 is installed.
  • the lower end 118 of the tethering element 30 may be moved to a position directly above the guide funnel above the connector to which it is to be attached. This can be accomplished by either maneuvering the tension leg platform 10 by applying a lateral force thereto with one or more tug boats, or by rotating the tethering element 30 until a thrusting means 130 thereof is properly directed for moving the lower end 118 in a direction toward a position directly above the guide funnel to which it is desirably attached.
  • a thrusting means 130 is schematically illustrated in Fig. 11.
  • Fig. 11 illustrates a permanent vertical tethering element 30 with a portion thereof cut away to reveal a plug 132 sealing the inner passageway 129 below the thrusting means 130.
  • the thrust means 130 is actuated by pumping a liquid down the inner passage 129 and out the thrust means 130, which is merely a radially directed orifice, as indicated by the jet of fluid 134.
  • the rotation of the tethering element 30 may be accomplished manually if the tethering element is suspended from derrick 28 on a swivel.
  • the lower end 118 of the permanent vertical tethering element 30 is preferably a standard hydraulically actuated wellhead type connector, and the connector means 110, 102 and 104 are each preferably a standard wellhead.
  • the final connection is made by stabbing the lower end 118 of the permanent vertical tethering element 30 into the guide funnel 108.
  • the guide funnel 108 guides the lower end 118 of the permanent vertical tethering element 30 into engagement with the connector means 102 and the connection therebetween is accomplished by the conventional hydraulic actuator.

Landscapes

  • Engineering & Computer Science (AREA)
  • Geology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • Ocean & Marine Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Earth Drilling (AREA)

Claims (16)

1. Un procédé d'amarrage provisoire d'une structure flottante (10), ce procédé comprenant la phase de préparation d'un certain montage de lignes d'amarrage provisoire (18) qui s'étendent entre la structure flottante et des moyens d'ancrage (20) positionnés sur le fond (16) d'une masse d'eau (14), lesdites lignes d'amarrage provisoire ayant leurs premières extrémités (36) fixées auxdits moyens d'ancrage, caractérisé par (a) le raccordement d'une série de lignes d'ancre (40) aux deuxièmes extrémités (38) des lignes d'amarrage provisoire; (b) le raccordement de ces lignes d'ancre à des moyens de halage (60) fixés à la structure flottante; (c) le relevage desdites lignes d'ancre et d'une partie de chacune des lignes d'amarrage provisoire à bord de ladite structure flottante jusqu'à ce que cette structure flottante soit située à peu près dans une position directement au-dessus des moyens d'ancrage; et (d) la tension de chacune desdites lignes d'amarrage provisoire.
2. Le procédé selon la revendication 1, caractérisé en ce que la phase (d) comporte la tension desdites lignes d'amarrage provisoire (18) de telle manière qu'une contrainte de tension sur chacune de ces lignes d'amarrage provisoire est supérieure à la valeur des forces cycliques exercées sur elle, ce qui évite toutes forces de rupture sur lesdites lignes d'amarrage provisoire, forces qui, autrement, pourraient se développer si lesdites lignes d'amarrage provisoire prenaient du mou.
3. Le procédé selon la revendication 1 ou 2, comprenant en outre la phase consistant à positionner ladite structure flottante (10) suffisamment près de la position située directement au-dessus des moyens d'ancrage (20) pour que la ligne d'ancre (40) puissent être assemblées à ladite structure flottante, lesdites phases (a) et (c) étant éxécutées avant ladite phase de positionnement et ladite phase (b) étant exécutée après ladite phase de positionnement.
4. Le procédé selon l'une des revendications 1 à 3 dans lequel la phase (d) consiste à augmenter la force de tension appliquée à chacune des lignes d'amarrage provisoire (18) en utilisant des compensateurs de houle (64).
5. Le procédé selon la revendication 4, dans lequel lesdites forces de tension appliquées aux lignes d'amarrage provisoire (18) par les compensateurs de houle (64) sont augmentées, pour réaliser la phase (d), par l'accroissement d'une pression hydraulique constante appliquée au piston (68) de chacun desdits compensateurs de houle.
6. Le procédé selon l'une des revendications 1 à 3, dans lequel la phase (d) comprend les phases de verrouillage des lignes d'amarrage provisoire (18) sur ladite structure flottante (10) pour fixer une longueur, et ensuite, de déballastage de ladite structure flottante.
7. Le procédé selon l'une des revendications 1 à 3, dans lequel la phase (d) comporte la tendre des lignes d'amarrage provisoire (18) au moyen d'un treuil à moteur.
8. Le procédé selon l'une des revendications 1 à 7, comprenant en outre une phase consistant, avant la phase (d), à appliquer une force horizontale à ladite structure flottante (10) pour l'éloigner horizontalement de la position située immédiatement au-dessus des moyens d'ancrage (20), d'une distance suffisante pour appliquer à chacune des lignes d'amarrage provisoire (18) une tension temporaire suffisamment grande pour éviter que des forces de rupture ne soient appliquées auxdites lignes d'amarrage provisoire sous l'effet de forces cycliques qui agissent sur elles.
9. Le procédé selon la revendication 8, dans lequel ladite phase d'application d'une force consiste à appliquer au moins une partie de cette force horizontale à la structure flottante (10) au moyen d'un remorqueur (93).
10. Le procédé selon l'une des revendications 1 à 9, dans lequel la phase (a) comprend des phases de descente des premières extrémités (36) des lignes d'amarrage provisoire (18) sur les moyens d'ancrage (20) à partir d'une deuxième structure flottante (44).
11. Le procédé selon la revendication 10, comprenant en outre une phase consistant à déposer lesdites lignes d'amarrage provisoire (18) sur fond (16) après que la première extrémité (36) de ces lignes ait été fixée aux moyens d'ancrage (20), lignes d'amarrage étant disposées selon un schéma déployée sur fond avant la phase (c).
12. Le procédé selon l'une des revendications 1 à 11, en combinaison avec un procédé d'amarrage définitif de la structure, consistant à monter un élément vertical d'amarrage définitif (30) entre la structure flottante (10) et les moyens d'ancrage (20), en descendant cet élément vertical d'amarrage définitif depuis la structure flottante alors que cette structure flottante est amarrée provisoirement, et en reliant une extrémité inférieure (18) dudit élément vertical d'amarrage définitif aux moyens d'ancrage.
13. Le procédé selon la revendication 12, comprenant en outre des phases consistant, avant la phase de descente, à prévoir sur les moyens d'ancrage (20) un entonnoir de guidage (108) ouvert vers le haut, placé au-dessus d'un connecteur (102) et servant à fixer ladite extrémité inférieure (118) de l'élément vertical d'amarrage définitif (30) aux moyens d'amarrage et, avant la phase de fixation de l'extrémité inférieure de l'élément vertical d'amarrage définitif auxdits moyens d'ancrage à, enfoncer cette extrémité inférieure de l'élément vertical d'amarrage définitif dans l'entonnoir de guidage et à guider de cette façon l'extrémité inférieur de l'élément vertical d'amarrage définitif en prise avec le connecteur.
14. Le procédé selon la revendication 12 ou 13, comprenant en outre des phases consistant à monter des éléments verticaux d'amarrage définitif (30) additionnels entre la structure flottante (10) et les moyens d'ancrage (20) et, ensuite à libérer les moyens d'amarrage provisoire (18) de manière que la structure flottante soit amarrée exclusivement par les éléments verticaux d'amarrage définitif.
15. Un dispositif pour amarrer provisoirement une structure flottante, comprenant des moyens d'ancrage (20) positionnés sur le fond (16) d'une nappe d'eau (14), et une série de lignes d'amarrage provisoire (18) ayant des premières extrémités (36) fixées auxdits moyens d'ancrage et adaptées pour s'étendre entre la structure et les moyens d'ancrage, caractérisé par une série de lignes d'ancre (40) reliées aux deuxièmes extrémités (38) des lignes d'amarrage provisoire, des moyens de halage (60) fixés à la structure flottante pour haler la série de lignes d'ancre et une partie de chacune des lignes d'amarrage provisoire à board de la structure flottante jusqu'à ce que cette structure flottante soit placée sensiblement dans une position directement au-dessus des moyens d'ancrage, et des moyens de tension (64) pour tendre la série de lignes d'amarrage provisoire de manière qu'une contrainte de tension exercée sur chacune de ces lignes d'amarrage provisoire soit supérieure à la valeur des forces cycliques exercées sur chacune desdites lignes d'amarrage provisoire.
16. Dispositif selon la revendication 15, dans lequel les moyens de tension comprennent des moyens compensateurs de houle (64) destinés à exercer une tension à peu près constante sur chacune des lignes d'amarrage provisoire (18).
EP19810303541 1980-08-04 1981-08-03 Ancrage d'une structure flottante Expired EP0045653B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US175101 1980-08-04
US06/175,101 US4352599A (en) 1980-08-04 1980-08-04 Permanent mooring of tension leg platforms
US180767 1980-08-22
US06/180,767 US4354446A (en) 1980-08-22 1980-08-22 Temporary mooring of tension leg platforms

Publications (2)

Publication Number Publication Date
EP0045653A1 EP0045653A1 (fr) 1982-02-10
EP0045653B1 true EP0045653B1 (fr) 1985-04-10

Family

ID=26870864

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19810303541 Expired EP0045653B1 (fr) 1980-08-04 1981-08-03 Ancrage d'une structure flottante

Country Status (2)

Country Link
EP (1) EP0045653B1 (fr)
DE (1) DE3169824D1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NO309233B1 (no) * 1995-06-07 2001-01-02 Aker Eng As Fremgangsmåte ved installasjon av strekkstagplattform
CN113212657A (zh) * 2021-05-26 2021-08-06 中国能源建设集团广东省电力设计研究院有限公司 一种自安装式海上平台

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1525882A (fr) * 1966-02-09 1968-05-24 Inst Francais Du Petrole Procédé d'ancrage d'une installation flottante au moyen d'amarres à tension contrôlée
FR2413258A1 (fr) * 1977-12-30 1979-07-27 Metalliques Entrepr Cie Fse Perfectionnements apportes aux ensembles du genre des plates-formes off-shore, ancrees par des cables sous tension, notamment verticaux
US4226555A (en) * 1978-12-08 1980-10-07 Conoco, Inc. Mooring system for tension leg platform

Also Published As

Publication number Publication date
EP0045653A1 (fr) 1982-02-10
DE3169824D1 (en) 1985-05-15

Similar Documents

Publication Publication Date Title
CA1257539A (fr) Colonne souple d'extraction
US4701143A (en) Vessel mooring system and method for its installation
US8083439B2 (en) Riser support system for use with an offshore platform
US3540396A (en) Offshore well apparatus and system
US4468157A (en) Tension-leg off shore platform
US4100752A (en) Subsea riser system
US4354446A (en) Temporary mooring of tension leg platforms
EP1097287B1 (fr) Rondin flottant de support de colonnes montantes de production
US4351258A (en) Method and apparatus for tension mooring a floating platform
US4352599A (en) Permanent mooring of tension leg platforms
CA1155762A (fr) Guides de raccordement
US4083193A (en) Offshore apparatus and method for installing
US4881852A (en) Method and apparatus for tensioning the tethers of a tension leg platform
US5067429A (en) Method for mooring and connecting an end of a flexible line with a conduit of a floating offshore edifice
US4687377A (en) Method and apparatus for subsea flexible conduit installation
US4780026A (en) Tension leg platform and installation method therefor
EP0045653B1 (fr) Ancrage d'une structure flottante
EA001885B1 (ru) Способ проведения буровых работ на морском дне с использованием одного трубопровода
GB2069450A (en) Self-standing production riser
EP1109974B1 (fr) Systeme de blocage lateral de colonne montante et d'installation pour plate-forme de forage en mer
EP0716011A1 (fr) Système de production avec plate-forme à jambes de tension
WO1999014462A1 (fr) Installation de colonne montante et systeme de colonne montante
CA1163552A (fr) Colonne montante autostable pour l'implantation en milieu marin
ZA200402782B (en) Achieving hydrostatic stability of a floating structure.
Bensimon et al. Deepwater Installation of a Large Capacity FPSO with Large Number of Risers in the Marlim Field

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): DE FR GB IT NL

17P Request for examination filed

Effective date: 19820402

ITF It: translation for a ep patent filed
GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Designated state(s): DE FR GB IT NL

REF Corresponds to:

Ref document number: 3169824

Country of ref document: DE

Date of ref document: 19850515

ET Fr: translation filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19900713

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19900822

Year of fee payment: 10

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 19900828

Year of fee payment: 10

ITTA It: last paid annual fee
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19900831

Year of fee payment: 10

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Effective date: 19910803

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19920301

GBPC Gb: european patent ceased through non-payment of renewal fee
NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19920430

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19920501

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST