EP0979923A1 - Installation for the exploitation of an offshore oil deposit and method for mounting a riser - Google Patents

Installation for the exploitation of an offshore oil deposit and method for mounting a riser Download PDF

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Publication number
EP0979923A1
EP0979923A1 EP99402019A EP99402019A EP0979923A1 EP 0979923 A1 EP0979923 A1 EP 0979923A1 EP 99402019 A EP99402019 A EP 99402019A EP 99402019 A EP99402019 A EP 99402019A EP 0979923 A1 EP0979923 A1 EP 0979923A1
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EP
European Patent Office
Prior art keywords
float
riser
platform
column
traction
Prior art date
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Granted
Application number
EP99402019A
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German (de)
French (fr)
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EP0979923B1 (en
Inventor
Pierre-Armand Thomas
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Technip Energies France SAS
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Technip France SAS
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Publication of EP0979923A1 publication Critical patent/EP0979923A1/en
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B19/00—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables
    • E21B19/002—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables specially adapted for underwater drilling
    • E21B19/004—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables specially adapted for underwater drilling supporting a riser from a drilling or production platform
    • E21B19/006—Handling rods, casings, tubes or the like outside the borehole, e.g. in the derrick; Apparatus for feeding the rods or cables specially adapted for underwater drilling supporting a riser from a drilling or production platform including heave compensators
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
    • E21B17/01—Risers
    • E21B17/012—Risers with buoyancy elements

Definitions

  • the present invention relates to an installation for operating a offshore deposit, of the type comprising a semi-submersible platform, at least one riser connecting the platform to the seabed F, and means for energizing said riser.
  • Semi-submersible platforms are intended for exploitation oil in deep seas or oceans. They include a shell supported by legs whose lower part is connected to a hollow base. The legs are fitted with buoyancy boxes. The base and the boxes ensure the buoyancy and the stability of the platform. The shell, attached to the legs, is held above the surface of the sea during operation of the installation.
  • risers generally designated by the English term “riser” connects the platform to the seabed. These columns risers are made of metal tubes.
  • the means of energizing risers have hydropneumatic actuators arranged between the head of the riser and the platform. These cylinders must have sufficient travel to compensate for displacement relative between the head of the riser and the platform. Of more, these must be strong enough to support the traction tensioning of the riser.
  • the object of the invention is to propose an operating installation in which the energization of the or each riser does not not require the implementation of complex and bulky means on the hull of the platform.
  • the invention relates to an operating installation a deposit at sea, of the aforementioned type, characterized in that the means for tensioning include, for the or each riser, at least one submerged float, connected at a point in the current part of the riser for its traction towards the surface, and a mechanism for traction of the riser, which mechanism is installed on the platform and applied at the top of the riser.
  • FIG 1 is schematically shown a platform semi-submersible self-elevating oil tanker 10. She is willing in a region of great depth, this being for example equal to 1300 m.
  • the platform essentially comprises an upper shell 12 extending above the surface M of the sea, when the platform is in the operating phase.
  • the shell 12 is connected, by four legs 14 provided buoyancy boxes 15, to a submerged lower base 16.
  • the upper shell contains technical residential buildings not represented as well as a derrick 18.
  • the shell 12 and the base 16 are all two square in shape and have through ducts in their center 20, 22 intended for the passage of a riser 24.
  • the column 24 is connected at its lower end to an operating well.
  • FIG 1 only a riser 24 is shown. In practical, several risers are arranged between the platform 10 and the seabed. Vertical conduits analogous to conduits 20 and 22 are provided for each riser.
  • the total weight of each riser 24 is, for example, 100 tons. Its diameter is 10 inches or about 25 cm.
  • Mooring lines 26, kept under tension, are installed between the submerged base 16 and the seabed to immobilize the platform above the deposit.
  • Each riser 24 is associated with setting means under pressure.
  • these tensioning means comprise, for each riser, at least one submerged float 28, connected at a point in the current part of the riser for its traction towards the surface, and a mechanism 30 for traction of the column rising, which mechanism is installed on platform 10 and is applied at the head of the riser 24.
  • the submerged float 28 is disposed at the depth of the base 16. It is thus mounted vertically displaceable in passage 22.
  • the float 28 has the shape of a sleeve.
  • the height of the float is for example 13 m and its diameter outside is for example 4.5 meters.
  • a passage 32 is defined along the axis of the float. The riser 24 is engaged through of it.
  • the diameter of the passage 32 is for example 1.7 m. It is advantageously greater than three times the current diameter of the column rising 24.
  • the float 28 consists of a toroidal box 34 delimited by metal walls.
  • the interior of the box is filled with synthetic foam 36 low density.
  • Box 34 is separated into three compartments separated by radial partitions 38 extending over the entire height of the float. These partitions arise along the wall delimiting the passage 32 and project radially out of the box 34.
  • Means 40 for guiding the float in the vertical direction are provided between the float 28 and the base 16 of the platform.
  • These guide means 40 for example include sliding pads 42 carried by the end of the radial partitions 38 projecting out of the box. These sliding pads are free to slide in slides guide 44 arranged longitudinally along passage 22.
  • the guide rails 44 are for example delimited by angles in U extending along the entire thickness of the base 16 is approximately 10 m.
  • the pads 42 are continuous and extend over a length equal to that of the guide rails 44. As a variant, these are constituted separate elements distributed over the height of the radial partitions 38.
  • the positions slides and pads are reversed.
  • the skates, which are then carried by the base, are integral with an attached guide jacket and fixed in the through conduit 22.
  • the guide sleeve is removed and replaced with a sleeve bearing new skates.
  • means 46 for axial connection of the float 28 and the riser 24 are provided in passage 32. These means of link are formed by a ball joint arrangement, allowing free travel angle of the riser 24 relative to the float 28.
  • This ball joint arrangement advantageously comprises an annular seat concave 48 integral with float 28 and a flange with a convex surface 50 carried by the riser 24.
  • the annular seat 48 is advantageously arranged in half bottom of passage 32. It defines a frustoconical concave surface 52 facing up. This is intended to form a bowl surface intended to support the flange 50.
  • the seat 48 is crossed by a conduit 54 suitable for the passage of the riser 24.
  • the conduit 54 for example has a diameter of 1 m.
  • the flange 50 facing the bearing surface 52 a convex surface 56, formed for example by a spherical crown.
  • the largest diameter of the flange 50 is less than the diameter from passage 32.
  • the riser 24 In its zone of connection to the collar 50, the riser 24 has an extra thickness, in order to reinforce its structure.
  • the thickness of the riser is gradually decreasing along two sections denoted 57, 58 oriented up and down respectively.
  • sections for example, each have a length of 3 m. They constitute sections of variable inertia ensuring a regular distribution constraints over their entire length.
  • the latches 60 each comprise for example a hydraulic actuator controllable from hull 12 or from an intervention vehicle remote controlled underwater. They allow the establishment of a pin 64 at the upper end of the slides 44.
  • the pins 64 can be moved between a retracted position in which they allow free sliding of the pads 42 in the slides 44 and an active stop position as shown in the Figures 2 and 3, in which they prohibit the upward movement of skates 42.
  • the float is sized to apply to the riser a tensile force between 1 and 3 times the weight of the column.
  • the force of traction exerted by the float is for example between 1000 kN and 2000 kN.
  • this tensile force is substantially equal at 1500 kN.
  • the force applied by the head tension 30 is substantially equal to 500 kN.
  • the float 28 is dimensioned to apply on the riser a tensile force greater than the force of traction applied by the head traction mechanism 30.
  • the pulling force of the float is between 1 and 10 times the traction force applied by the traction mechanism of head.
  • the float applies to the riser a traction force substantially equal to 3 times the applied traction force by the head traction mechanism 30.
  • the float is sized so that the capacity of the head traction mechanism is a maximum of 500 kN.
  • the head pull mechanism 30, shown in Figure 4 comprises two hydropneumatic cylinders 70 mounted in parallel.
  • a cable 76 for tensioning the column riser 24 is engaged around the pulleys. Cable 76 is passed over a return pulley 78 and directed towards the head of the riser at which it is fixed.
  • the jacks 70 are supplied with a hydraulic fluid by an assembly of hydraulic pressure regulations noted 80.
  • the variation hydraulic pressure in the jacks 70 allows the control of their travel.
  • the engagement of the cable 76 between the pulleys 72 and 74 ensures a reduction in the travel of the cylinders, so that for ensure at the head of the riser 24 a clearance axial of 15.2 m, the stroke of the cylinders is only 3.8 m.
  • the head traction mechanisms 30 are integrated into the thickness of the shell 12 as shown in Figure 1. Thus, they do not clutter not the upper hull deck 12.
  • the head traction means 30 are offset on the side walls of the hull, the cables 76 then circulating from the rail up to the column head through the shell 12.
  • the diameter of the conduit 32 through which the column passes rising 24 being much greater than the diameter thereof, and the connection between the float and the riser being provided by a ball joint, the column rising is free to move angularly relative to the float, this which reduces the stresses applied on the riser 24.
  • FIGS. 5A to 5E a first embodiment is illustrated. place of a riser 24.
  • the riser 24 is first submerged with its lower end kept away from the bottom F.
  • the float 28 is held in abutment against the pins 64, preventing thus the rise of the float.
  • the flange 50 is substantially to the depth of the seat 48.
  • the bottom of the float 28 is flush substantially bottom of the base 16.
  • the platform 10 is ballasted, for example by partially filling the base 16.
  • the platform 10 sinks to a depth l as shown in Figure 5B.
  • the depth l is for example equal to 1.5m.
  • the derrick 18 the column rising 24 is recalled upwards when lowering from the platform, so that the lower end of the riser stays away from the seabed F by an interval J and is for example one meter from the background.
  • the flange 50 is disposed above the seat 48 and is spaced therefrom by an interval K substantially equal to 1.5 m.
  • the next phase of the process first involves linking the mechanism head pull 30 to the riser 24, then gradually unpack the platform, until the flange 50 comes to bear on the seat 48, as shown in Figure 5D.
  • the platform 10 is thus raised by the interval K '.
  • the derrick 18 is gradually released to allow relative movement between the riser and the platform.
  • the float 28 exerts a restoring force towards the surface of the lower part of the riser.
  • the head traction means 30 are actuated so as to ensure the traction of the upper section of the riser 24 included between the derrick 18 and the float 28.
  • FIGS. 6A to 6D Another method of placing a riser in a installation according to the invention is illustrated in FIGS. 6A to 6D.
  • the hull 12 of the platform is equipped with 90 winches for hanging an annular ballast 92 above the float 28.
  • the annular ballast 92 is formed by two half-rings assembled around the riser 24. The length of the winch is sufficient to deposit ballast 92 on the upper annular surface of the float 28.
  • the weight of the ballast 92 is adapted to ensure the insertion of the float 28 towards the bottom.
  • the riser 24 is submerged with its lower end held at a distance of the bottom F.
  • the float 28 is in abutment against the pins 64.
  • ballast 92 is then conveyed as far as the float. So the float 28 is caused to sink as shown in Figure 6B ,.
  • the riser After sufficient insertion of the float 28, the riser is lowered and its lower end is connected to an operating well of oil as shown in Figure 6C. Because of the depression of float 28, the collar 50 of the riser is away from the seat 48. Under these conditions, the riser 24 is relaxed, allowing its connection to the operating well.
  • the ballast 92 is raised, as shown in FIG. 6D.
  • the float 28 tends to rise to the surface, so that it exerts on the riser 24 a force of upward traction applied on the flange 50.

Abstract

In an installation for extracting oil from seabed deposits, the rising column (24) of a semi-submersible platform (10) is kept under tension by one or more submerged float (28) and a pulling mechanism (30) mounted on the platform. An abutment holds the float against the platform. The float(s) are sized to apply a traction force on the rising column which is greater than that applied by the mechanism, preferably 1-3 times the weight of the column. The platform includes an immersed base (16) and a floating hull (12) connected by legs (14). The float(s) are placed at the depth of the base, which has vertical guides for each float. The base contains a vertical passage (22) for each float, in which the float can move axially. Each float contains a conduit through which the associated rising column extends. A universal joint links the float and the rising column, having a concave annular seat fixed to the float in the axial conduit and a convex collar carried on the column. The collar presses on the seat to apply the traction. The conduit has a diameter greater than three times that of the column. The traction mechanism at the top of the column has at least one hydro-pneumatic jack with a pulley assembly at each end on which at least one sling applies traction to the column. An Independent claim is also included for the installation of a rising column comprising ensuring the abutment holds the float vertically against the platform, submersing the column with its lower end held at a distance from the seabed, ballasting the platform, lowering the column and connecting it to the seabed, disengaging the abutment between the float and the platform, and deballasting the platform.

Description

La présente invention concerne une installation d'exploitation d'un gisement en mer, du type comportant une plate-forme semi-submersible, au moins une colonne montante reliant la plate-forme au fond marin F, et des moyens de mise sous tension de ladite colonne montante.The present invention relates to an installation for operating a offshore deposit, of the type comprising a semi-submersible platform, at least one riser connecting the platform to the seabed F, and means for energizing said riser.

Les plates-formes semi-submersibles sont destinées à l'exploitation pétrolière dans des mers ou océans de grande profondeur. Elles comportent une coque supportée par des jambes dont la partie inférieure est reliée à une embase creuse. Les jambes sont munies de caissons de flottabilité. L'embase et les caissons assurent la flottaison et la stabilité de la plate-forme. La coque, fixée sur les jambes, est maintenue au-dessus de la surface de la mer lors de l'exploitation de l'installation.Semi-submersible platforms are intended for exploitation oil in deep seas or oceans. They include a shell supported by legs whose lower part is connected to a hollow base. The legs are fitted with buoyancy boxes. The base and the boxes ensure the buoyancy and the stability of the platform. The shell, attached to the legs, is held above the surface of the sea during operation of the installation.

Une ou plusieurs colonnes montantes, généralement désignée par le terme anglais "riser" relie la plate-forme au fond marin. Ces colonnes montantes sont constituées de tubes métalliques.One or more risers, generally designated by the English term "riser" connects the platform to the seabed. These columns risers are made of metal tubes.

Leur longueur, qui correspond essentiellement à la profondeur du lieu d'exploitation est couramment de 1200 m et leur poids est de l'ordre de 100 tonnes.Their length, which essentially corresponds to the depth of the operating place is usually 1200 m and their weight is around 100 tonnes.

Afin d'éviter que les colonnes montantes ne se rompent, sous l'action des courants transversaux, il est connu de prévoir des moyens de mise sous tension de celles-ci. Ces moyens de mise sous tension exercent une force correspondant environ à une à deux fois le poids de la colonne montante.To prevent risers from breaking, under the action transverse currents, it is known to provide means for energizing them. These tensioning means exercise a force approximately one to two times the weight of the column rising.

Du fait du maintien en flottaison de la plate-forme, celle-ci est soumise d'une part aux variations du niveau de l'eau dues à la marée, et d'autre part aux mouvements de la houle. En conséquence, les moyens de mise sous tension des colonnes montantes doivent permettre de compenser le débattement vertical de la plate-forme au cours du temps. Le débattement vertical maximal est couramment de 4 à 12 m.Due to the floating buoyancy of the platform, it is subject on the one hand to variations in the water level due to the tide, and on the other hand to the swell movements. Consequently, the means of tensioning the risers must make it possible to compensate the vertical movement of the platform over time. The maximum vertical travel is commonly 4 to 12 m.

Dans les installations actuelles, les moyens de mise sous tension des colonnes montantes comportent des vérins à commande hydropneumatique disposés entre la tête de la colonne montante et la plate-forme. Ces vérins doivent avoir une course suffisante pour compenser le déplacement relatif entre la tête de la colonne montante et la plate-forme. De plus, ceux-ci doivent être suffisamment puissants pour supporter la traction de mise en tension de la colonne montante.In current installations, the means of energizing risers have hydropneumatic actuators arranged between the head of the riser and the platform. These cylinders must have sufficient travel to compensate for displacement relative between the head of the riser and the platform. Of more, these must be strong enough to support the traction tensioning of the riser.

Ainsi, on comprend que les vérins utilisés actuellement sont très encombrants et d'une technologie complexe.Thus, we understand that the cylinders currently used are very bulky and complex technology.

L'invention a pour but de proposer une installation d'exploitation dans laquelle, la mise sous tension de la ou chaque colonne montante ne nécessite pas la mise en oeuvre de moyens complexes et encombrants sur la coque de la plate-forme.The object of the invention is to propose an operating installation in which the energization of the or each riser does not not require the implementation of complex and bulky means on the hull of the platform.

A cet effet, l'invention a pour objet une installation d'exploitation d'un gisement en mer, du type précité, caractérisée en ce que les moyens de mise sous tension comportent, pour la ou chaque colonne montante, au moins un flotteur immergé, relié en un point de la partie courante de la colonne montante pour sa traction vers la surface, et un mécanisme de traction de la colonne montante, lequel mécanisme est installé sur la plate-forme et appliqué en tête de la colonne montante.To this end, the invention relates to an operating installation a deposit at sea, of the aforementioned type, characterized in that the means for tensioning include, for the or each riser, at least one submerged float, connected at a point in the current part of the riser for its traction towards the surface, and a mechanism for traction of the riser, which mechanism is installed on the platform and applied at the top of the riser.

Selon des modes particuliers de réalisation, l'installation comporte l'une ou plusieurs des caractéristiques suivantes:

  • le ou chaque flotteur est dimensionné pour appliquer sur la colonne montante, une force de traction supérieure à la force de traction appliquée par le mécanisme de traction de tête ;
  • le flotteur est dimensionné pour appliquer sur la colonne montante une force de traction comprise entre 1 et 3 fois le poids de la colonne montante ;
  • la plate-forme comporte une embase immergée et une coque émergée reliée par des jambes, le ou chaque flotteur étant disposé à la profondeur de ladite embase, laquelle embase comporte des moyens de guidage vertical du ou de chaque flotteur ;
  • l'embase comporte, pour chaque flotteur, un passage vertical au travers duquel le flotteur est mobile axialement ;
  • elle comporte des moyens de mise en butée du flotteur contre la plate-forme, suivant le sens ascendant ;
  • le ou chaque flotteur présente un conduit traversant dans lequel s'étend la colonne montante associée ;
  • les moyens assurant la liaison entre le ou chaque flotteur et la colonne montante associée comportent une rotule;
  • la rotule comporte un siège annulaire concave solidarisé audit flotteur dans le conduit axial et une collerette à surface convexe portée par la colonne montante, la collerette étant appliquée contre le siège concave pour l'application de la traction sur la colonne montante ;
  • le conduit traversant a un diamètre supérieur à trois fois le diamètre de la colonne montante ; et
  • le mécanisme de traction de tête comporte au moins un vérin hydropneumatique comportant à chaque extrémité un ensemble de poulies mouflées sur lesquelles est engagé au moins un brin de traction appliqué à ladite colonne montante.
According to particular embodiments, the installation includes one or more of the following characteristics:
  • the or each float is dimensioned to apply to the riser, a traction force greater than the traction force applied by the head traction mechanism;
  • the float is dimensioned to apply a tensile force of between 1 and 3 times the weight of the riser to the riser;
  • the platform comprises a submerged base and an emerged hull connected by legs, the or each float being disposed at the depth of said base, which base comprises means for vertically guiding the or each float;
  • the base comprises, for each float, a vertical passage through which the float is axially movable;
  • it comprises means for abutting the float against the platform, in the upward direction;
  • the or each float has a through duct in which the associated riser extends;
  • the means ensuring the connection between the or each float and the associated riser comprise a ball joint;
  • the ball joint comprises a concave annular seat secured to said float in the axial duct and a flange with a convex surface carried by the riser, the flange being applied against the concave seat for the application of traction on the riser;
  • the through conduit has a diameter greater than three times the diameter of the riser; and
  • the head traction mechanism comprises at least one hydropneumatic cylinder comprising at each end a set of reeled pulleys on which is engaged at least one traction strand applied to said riser.

L'invention a également pour objet des procédés d'implantation d'une colonne montante d'une installation du type précité, caractérisé en ce qu'il comporte les étapes successives consistant à:

  • a - assurer la mise en butée verticale du flotteur contre la plate-forme;
  • b - immerger la colonne montante avec son extrémité inférieure maintenue à distance du fond marin ;
  • c- ballaster la plate-forme ;
  • d- descendre la colonne montante et relier celle-ci au fond marin F;
  • e - dégager la butée entre le flotteur et la plate-forme ; et
  • f- déballaster la plate-forme.
    • The invention also relates to methods of implanting a riser of an installation of the aforementioned type, characterized in that it comprises the successive stages consisting in:
  • a - ensure the vertical abutment of the float against the platform;
  • b - immerse the riser with its lower end kept away from the seabed;
  • c- ballaster the platform;
  • d- lower the riser and connect it to the seabed F;
  • e - clear the stop between the float and the platform; and
  • f- unpack the platform.

    • Suivant un mode particulier de mise en oeuvre le procédé comporte les étapes consistant à :

  • a - assurer la mise en butée du flotteur contre la plate-forme ;
  • b - immerger la colonne montante avec son extrémité inférieure maintenue à distance du fond marin ;
  • c - enfoncer vers le bas le flotteur par mise en place d'un lest sur le flotteur ;
  • d - descendre la colonne montante et relier celle-ci au fond marin ,
  • e - dégager la butée entre le flotteur et la plate-forme ; et
  • f - retirer le lest pesant sur le flotteur.
    • According to a particular mode of implementation, the method comprises the steps consisting in:
  • a - ensuring the abutment of the float against the platform;
  • b - immerse the riser with its lower end kept away from the seabed;
  • c - push the float down by placing a ballast on the float;
  • d - lower the riser and connect it to the seabed,
  • e - clear the stop between the float and the platform; and
  • f - remove the ballast weighing on the float.

    • L'invention sera mieux comprise à la lecture de la description qui va suivre, donnée uniquement à titre d'exemple et faite en se référant aux dessins sur lesquels :

    • la figure 1 est une vue en élévation d'une installation d'exploitation pétrolière selon l'invention;
    • les figures 2 et 3 sont des vues en coupe respectivement longitudinales et transversales d'un flotteur de traction de la colonne montante de l'installation de la figure 1;
    • la figure 4 est une vue en perspective de moyens de traction de tête d'une colonne montante;
    • les figures 5A, 5B, 5C, 5D et 5E sont des vues schématiques montrant l'installation pétrolière de la figure 1 à des stades successifs d'implantation d'une colonne montante; et
    • les figures 6A, 6B, 6C, 6D sont des vues analogues aux figures 5A à 5E, illustrant un second procédé de mise en place d'une colonne montante.
    The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the drawings in which:
    • Figure 1 is an elevational view of an oil exploitation installation according to the invention;
    • Figures 2 and 3 are sectional views respectively longitudinal and transverse of a traction float of the riser of the installation of Figure 1;
    • Figure 4 is a perspective view of head traction means of a riser;
    • FIGS. 5A, 5B, 5C, 5D and 5E are schematic views showing the petroleum installation of FIG. 1 at successive stages of implantation of a riser; and
    • Figures 6A, 6B, 6C, 6D are views similar to Figures 5A to 5E, illustrating a second method of placing a riser.

    Sur la figure 1, est représentée schématiquement une plate-forme pétrolière auto-élévatrice 10 de type semi-submersible. Elle est disposée dans une région de grande profondeur, celle-ci étant par exemple égale à 1300 m.In Figure 1, is schematically shown a platform semi-submersible self-elevating oil tanker 10. She is willing in a region of great depth, this being for example equal to 1300 m.

    La plate-forme comporte essentiellement une coque supérieure 12 s'étendant au-dessus de la surface M de la mer, lorsque la plate-forme est en phase d'exploitation. La coque 12 est reliée, par quatre jambes 14 munies de caissons de flottabilité 15, à une embase inférieure immergée 16. La coque supérieure comporte des bâtiments techniques d'habitation non représentés ainsi qu'un derrick 18. La coque 12 et l'embase 16 sont toutes deux de forme carrée et comportent en leur centre des conduits traversants 20, 22 destinés au passage d'une colonne montante 24. La colonne 24 est connectée à son extrémité inférieure à un puits d'exploitation.The platform essentially comprises an upper shell 12 extending above the surface M of the sea, when the platform is in the operating phase. The shell 12 is connected, by four legs 14 provided buoyancy boxes 15, to a submerged lower base 16. The upper shell contains technical residential buildings not represented as well as a derrick 18. The shell 12 and the base 16 are all two square in shape and have through ducts in their center 20, 22 intended for the passage of a riser 24. The column 24 is connected at its lower end to an operating well.

    Sur la figure 1, seule une colonne montante 24 est représentée. En pratique, plusieurs colonnes montantes sont disposées entre la plate-forme 10 et le fond marin. Des conduits verticaux analogues aux conduits 20 et 22 sont prévus pour chaque colonne montante. In Figure 1, only a riser 24 is shown. In practical, several risers are arranged between the platform 10 and the seabed. Vertical conduits analogous to conduits 20 and 22 are provided for each riser.

    Le poids total de chaque colonne montante 24 est par exemple de 100 tonnes. Son diamètre est de 10 pouces soit environ 25 cm.The total weight of each riser 24 is, for example, 100 tons. Its diameter is 10 inches or about 25 cm.

    Des lignes d'amarrage 26, maintenues sous tension, sont installées entre l'embase immergée 16 et le fond marin pour immobiliser la plate-forme au-dessus du gisement.Mooring lines 26, kept under tension, are installed between the submerged base 16 and the seabed to immobilize the platform above the deposit.

    Chaque colonne montante 24 est associée à des moyens de mise sous tension. Selon l'invention, ces moyens de mise sous tension comportent, pour chaque colonne montante, au moins un flotteur immergé 28, relié en un point de la partie courante de la colonne montante pour sa traction vers la surface, et un mécanisme 30 de traction de la colonne montante, lequel mécanisme est installé sur la plate-forme 10 et est appliqué en tête de la colonne montante 24.Each riser 24 is associated with setting means under pressure. According to the invention, these tensioning means comprise, for each riser, at least one submerged float 28, connected at a point in the current part of the riser for its traction towards the surface, and a mechanism 30 for traction of the column rising, which mechanism is installed on platform 10 and is applied at the head of the riser 24.

    Le flotteur immergé 28 est disposé à la profondeur de l'embase 16. Il est ainsi monté déplaçable verticalement dans le passage 22.The submerged float 28 is disposed at the depth of the base 16. It is thus mounted vertically displaceable in passage 22.

    Sur les figures 2 et 3 est représenté en coupe à plus grande échelle le flotteur 28 traversant le passage 22.In Figures 2 and 3 is shown in section on a larger scale the float 28 crossing the passage 22.

    Comme représenté sur ces figures, le flotteur 28 présente la forme d'un manchon. La hauteur du flotteur est par exemple de 13 m et son diamètre extérieur est par exemple de 4,5 mètres. Un passage 32 est défini suivant l'axe du flotteur. La colonne montante 24 est engagée au travers de celui-ci.As shown in these figures, the float 28 has the shape of a sleeve. The height of the float is for example 13 m and its diameter outside is for example 4.5 meters. A passage 32 is defined along the axis of the float. The riser 24 is engaged through of it.

    Le diamètre du passage 32 est par exemple de 1,7 m. Il est avantageusement supérieur à trois fois le diamètre courant de la colonne montante 24.The diameter of the passage 32 is for example 1.7 m. It is advantageously greater than three times the current diameter of the column rising 24.

    Le flotteur 28 est constitué d'un caisson toroïdal 34 délimité par des parois métalliques. L'intérieur du caisson est empli d'une mousse synthétique 36 de faible densité. Le caisson 34 est séparé en trois compartiments distincts par des cloisons radiales 38 s'étendant sur toute la hauteur du flotteur. Ces cloisons prennent naissance le long de la paroi délimitant le passage 32 et font saillie radialement hors du caisson 34.The float 28 consists of a toroidal box 34 delimited by metal walls. The interior of the box is filled with synthetic foam 36 low density. Box 34 is separated into three compartments separated by radial partitions 38 extending over the entire height of the float. These partitions arise along the wall delimiting the passage 32 and project radially out of the box 34.

    Des moyens 40 de guidage du flotteur suivant la direction verticale sont prévus entre le flotteur 28 et l'embase 16 de la plate-forme. Ces moyens de guidage 40 comportent par exemple des patins de glissement 42 portés par l'extrémité des cloisons radiales 38 faisant saillie hors du caisson. Ces patins de glissement sont libres de coulisser dans des glissières de guidage 44 disposées longitudinalement suivant le passage 22. Les glissières de guidage 44 sont par exemple délimitées par des cornières en U s'étendant suivant toute l'épaisseur de l'embase 16 soit environ 10 m.Means 40 for guiding the float in the vertical direction are provided between the float 28 and the base 16 of the platform. These guide means 40 for example include sliding pads 42 carried by the end of the radial partitions 38 projecting out of the box. These sliding pads are free to slide in slides guide 44 arranged longitudinally along passage 22. The guide rails 44 are for example delimited by angles in U extending along the entire thickness of the base 16 is approximately 10 m.

    Les patins 42 sont continus et s'étendent sur une longueur égale à celle des glissières de guidage 44. En variante, ceux-ci sont constitués d'éléments distincts répartis sur la hauteur des cloisons radiales 38.The pads 42 are continuous and extend over a length equal to that of the guide rails 44. As a variant, these are constituted separate elements distributed over the height of the radial partitions 38.

    Suivant une autre variante de réalisation non représentée, les positions des glissières et des patins sont inversées. Les patins, qui sont alors portés par l'embase, sont solidaires d'une chemise de guidage rapportée et fixée dans le conduit traversant 22. Lorsque les patins sont usés, la chemise de guidage est retirée et remplacée par une chemise portant des patins neufs.According to another alternative embodiment not shown, the positions slides and pads are reversed. The skates, which are then carried by the base, are integral with an attached guide jacket and fixed in the through conduit 22. When the pads are worn, the guide sleeve is removed and replaced with a sleeve bearing new skates.

    Par ailleurs, des moyens 46 de liaison axiale du flotteur 28 et de la colonne montante 24 sont prévus dans le passage 32. Ces moyens de liaison sont formés par un agencement à rotule, permettant un libre débattement angulaire de la colonne montante 24 par rapport au flotteur 28.Furthermore, means 46 for axial connection of the float 28 and the riser 24 are provided in passage 32. These means of link are formed by a ball joint arrangement, allowing free travel angle of the riser 24 relative to the float 28.

    Cet agencement à rotule comporte avantageusement un siège annulaire concave 48 solidaire du flotteur 28 et une collerette à surface convexe 50 portée par la colonne montante 24.This ball joint arrangement advantageously comprises an annular seat concave 48 integral with float 28 and a flange with a convex surface 50 carried by the riser 24.

    Le siège annulaire 48 est disposé avantageusement dans la moitié inférieure du passage 32. Il définit une surface concave tronconique 52 orientée vers le haut. Celle-ci est destinée à former une surface en cuvette destinée à l'appui de la collerette 50. Le siège 48 est traversé par un conduit 54 adapté pour le passage de la colonne montante 24. Le conduit 54 a par exemple un diamètre de 1 m.The annular seat 48 is advantageously arranged in half bottom of passage 32. It defines a frustoconical concave surface 52 facing up. This is intended to form a bowl surface intended to support the flange 50. The seat 48 is crossed by a conduit 54 suitable for the passage of the riser 24. The conduit 54 for example has a diameter of 1 m.

    La collerette 50, présente en regard de la surface d'appui 52 une surface convexe 56, formée par exemple par une couronne sphérique.The flange 50, facing the bearing surface 52 a convex surface 56, formed for example by a spherical crown.

    Le plus grand diamètre de la collerette 50 est inférieur au diamètre du passage 32. The largest diameter of the flange 50 is less than the diameter from passage 32.

    Dans sa zone de liaison à la collerette 50, la colonne montante 24 présente une surépaisseur, afin de renforcer sa structure.In its zone of connection to the collar 50, the riser 24 has an extra thickness, in order to reinforce its structure.

    Depuis la collerette 50, l'épaisseur de la colonne montante est progressivement décroissante suivant deux tronçons notés 57, 58 orientés respectivement vers le haut et vers le bas.From the collar 50, the thickness of the riser is gradually decreasing along two sections denoted 57, 58 oriented up and down respectively.

    Ces tronçons ont par exemple chacun une longueur de 3 m. Ils constituent des tronçons d'inertie variable assurant une répartition régulière des contraintes sur toute leur longueur.These sections, for example, each have a length of 3 m. They constitute sections of variable inertia ensuring a regular distribution constraints over their entire length.

    Par ailleurs, à la périphérie du passage 22 sont prévues sur la face supérieure de l'embase 16 trois verrous 60 constituant des butées escamotables adaptées pour retenir sélectivement le flotteur 28 et éviter la remontée de celui-ci.Furthermore, at the periphery of passage 22 are provided on the face upper of base 16 three locks 60 constituting retractable stops adapted to selectively hold the float 28 and prevent the ascent of it.

    Les verrous 60, comportent chacun par exemple un actionneur hydraulique commandable depuis la coque 12 ou depuis un engin d'intervention sous-marine télécommandé. Ils permettent la mise en place d'un penne 64 à l'extrémité supérieure des glissières 44.The latches 60 each comprise for example a hydraulic actuator controllable from hull 12 or from an intervention vehicle remote controlled underwater. They allow the establishment of a pin 64 at the upper end of the slides 44.

    Les pennes 64 sont déplaçables entre une position escamotée dans laquelle ils autorisent un libre coulissement des patins 42 dans les glissières 44 et une position active de butée telle que représentée sur les figures 2 et 3, dans laquelle ils interdisent le déplacement vers le haut des patins 42.The pins 64 can be moved between a retracted position in which they allow free sliding of the pads 42 in the slides 44 and an active stop position as shown in the Figures 2 and 3, in which they prohibit the upward movement of skates 42.

    Le flotteur est dimensionné pour appliquer sur la colonne montante une force de traction comprise entre 1 et 3 fois le poids de la colonne. Pour une colonne montante 24 ayant un poids de 100 tonnes, la force de traction exercée par le flotteur est par exemple comprise entre 1000 kN et 2000 kN. Avantageusement, cette force de traction est sensiblement égale à 1500 kN. Dans ces conditions, la force appliquée par le mécanisme de traction de tête 30 est sensiblement égale à 500 kN.The float is sized to apply to the riser a tensile force between 1 and 3 times the weight of the column. For a riser 24 having a weight of 100 tonnes, the force of traction exerted by the float is for example between 1000 kN and 2000 kN. Advantageously, this tensile force is substantially equal at 1500 kN. Under these conditions, the force applied by the head tension 30 is substantially equal to 500 kN.

    De manière générale, le flotteur 28 est dimensionné pour appliquer sur la colonne montante une force de traction supérieure à la force de traction appliquée par le mécanisme de traction de tête 30. Generally, the float 28 is dimensioned to apply on the riser a tensile force greater than the force of traction applied by the head traction mechanism 30.

    Avantageusement, la force de traction du flotteur est comprise entre 1 et 10 fois la force de traction appliquée par le mécanisme de traction de tête.Advantageously, the pulling force of the float is between 1 and 10 times the traction force applied by the traction mechanism of head.

    Dans la pratique, le flotteur applique sur la colonne montante une force de traction sensiblement égale à 3 fois la force de traction appliquée par le mécanisme de traction de tête 30.In practice, the float applies to the riser a traction force substantially equal to 3 times the applied traction force by the head traction mechanism 30.

    Le dimensionnement du flotteur est effectué pour que la capacité du mécanisme de traction de tête soit au maximum de 500 kN.The float is sized so that the capacity of the head traction mechanism is a maximum of 500 kN.

    Le mécanisme de traction de tête 30, représenté sur la figure 4 comporte deux vérins hydropneumatiques 70 montés en parallèle.The head pull mechanism 30, shown in Figure 4 comprises two hydropneumatic cylinders 70 mounted in parallel.

    A chaque extrémité des vérins sont montées quatre poulies mouflées notées 72 et 74. Un câble 76 de mise sous tension de la colonne montante 24 est engagé autour des poulies. Le câble 76 est passé sur une poulie de renvoi 78 et dirigé vers la tête de la colonne montante à laquelle elle est fixée.At each end of the cylinders are mounted four reeved pulleys noted 72 and 74. A cable 76 for tensioning the column riser 24 is engaged around the pulleys. Cable 76 is passed over a return pulley 78 and directed towards the head of the riser at which it is fixed.

    Les vérins 70 sont alimentés en un fluide hydraulique par un ensemble de régulations de la pression hydraulique notées 80. La variation de la pression hydraulique dans les vérins 70 permet la commande de leur débattement.The jacks 70 are supplied with a hydraulic fluid by an assembly of hydraulic pressure regulations noted 80. The variation hydraulic pressure in the jacks 70 allows the control of their travel.

    L'engagement du câble 76 entre les poulies mouflées 72 et 74 assure une démultiplication du débattement des vérins, de sorte que pour assurer au niveau de la tête de la colonne montante 24 un débattement axial de 15,2 m, la course des vérins n'est que de 3,8 m.The engagement of the cable 76 between the pulleys 72 and 74 ensures a reduction in the travel of the cylinders, so that for ensure at the head of the riser 24 a clearance axial of 15.2 m, the stroke of the cylinders is only 3.8 m.

    Les mécanismes de traction de tête 30 sont intégrés dans l'épaisseur de la coque 12 comme représenté sur la figure 1. Ainsi, ils n'encombrent pas le pont supérieur de la coque 12.The head traction mechanisms 30 are integrated into the thickness of the shell 12 as shown in Figure 1. Thus, they do not clutter not the upper hull deck 12.

    En variante, les moyens 30 de traction de tête sont déportés sur les parois latérales de la coque, les câbles 76 circulant alors depuis le bastingage jusqu'à la tête de colonne au travers de la coque 12.As a variant, the head traction means 30 are offset on the side walls of the hull, the cables 76 then circulating from the rail up to the column head through the shell 12.

    On conçoit qu'avec une telle installation, la colonne montante 24 est sollicitée vers le haut à la fois par le flotteur 28 et par les moyens de traction de tête 30. It is understood that with such an installation, the riser 24 is urged upward both by the float 28 and by the traction means head 30.

    Ainsi, du fait de la traction exercée par le flotteur 28, la capacité de traction des moyens 30 peut être réduite. Ainsi, il n'est pas nécessaire d'utiliser des vérins encombrants ayant une course longue correspondant au déplacement maximal rencontré entre la tête de la colonne montante et la plate-forme.Thus, due to the traction exerted by the float 28, the ability to traction of the means 30 can be reduced. So there is no need to use bulky cylinders with a corresponding long stroke at the maximum displacement encountered between the head of the riser and the platform.

    De plus, le diamètre du conduit 32 dans lequel passe la colonne montante 24 étant très supérieur au diamètre de celle-ci, et la liaison entre le flotteur et la colonne montante étant assurée par une rotule, la colonne montante est libre de se déplacer angulairement par rapport au flotteur, ce qui réduit les contraintes appliquées sur la colonne montante 24.In addition, the diameter of the conduit 32 through which the column passes rising 24 being much greater than the diameter thereof, and the connection between the float and the riser being provided by a ball joint, the column rising is free to move angularly relative to the float, this which reduces the stresses applied on the riser 24.

    Sur les figures 5A à 5E est illustré un premier mode de mise en place d'une colonne montante 24.In FIGS. 5A to 5E, a first embodiment is illustrated. place of a riser 24.

    Comme représenté sur la figure 5A, la colonne montante 24 est d'abord immergée avec son extrémité inférieure maintenue à distance du fond F. Le flotteur 28 est maintenu en butée contre les pennes 64, interdisant ainsi la remontée du flotteur. Dans cette position, la collerette 50 est sensiblement à la profondeur du siège 48. Le fond du flotteur 28 affleure sensiblement de fond de l'embase 16.As shown in FIG. 5A, the riser 24 is first submerged with its lower end kept away from the bottom F. The float 28 is held in abutment against the pins 64, preventing thus the rise of the float. In this position, the flange 50 is substantially to the depth of the seat 48. The bottom of the float 28 is flush substantially bottom of the base 16.

    Lors de l'étape suivante du procédé, la plate-forme 10 est ballastée, par exemple par remplissage partiel de l'embase 16. Ainsi, la plate-forme 10 s'enfonce d'une profondeur l comme indiqué sur la figure 5B. La profondeur l est par exemple égale à 1,5m. Grâce au derrick 18, la colonne montante 24 est rappelée vers le haut lors de la descente de la plate-forme, afin que l'extrémité inférieure de la colonne montante reste écartée du fond marin F d'un intervalle J et se trouve par exemple à un mètre du fond. Dans cette position, la collerette 50 est disposée au-dessus du siège 48 et est écartée de celui-ci d'un intervalle K sensiblement égal à 1,5 m.During the next step of the process, the platform 10 is ballasted, for example by partially filling the base 16. Thus, the platform 10 sinks to a depth l as shown in Figure 5B. The depth l is for example equal to 1.5m. Thanks to the derrick 18, the column rising 24 is recalled upwards when lowering from the platform, so that the lower end of the riser stays away from the seabed F by an interval J and is for example one meter from the background. In this position, the flange 50 is disposed above the seat 48 and is spaced therefrom by an interval K substantially equal to 1.5 m.

    Après cette étape, et comme représenté sur la figure 5C, la colonne montante 24 est descendue jusqu'au fond et est connectée sur un puits d'exploitation préalablement forée et entubée. Lors de cette descente, la profondeur d'immersion de la plate-forme est maintenue constante. After this step, and as shown in Figure 5C, the column riser 24 has descended to the bottom and is connected to a well previously drilled and clouded. During this descent, the platform immersion depth is kept constant.

    Dans cette position, la collerette 50 est écartée du siège 48 d'un intervalle K' sensiblement égal à 0,5m. Le tronçon de la colonne montante compris entre son extrémité inférieure et le flotteur est détendu.In this position, the flange 50 is spaced from the seat 48 by a interval K 'substantially equal to 0.5 m. The riser section between its lower end and the float is relaxed.

    La phase suivante du procédé consiste d'abord à lier le mécanisme de traction de tête 30 à la colonne montante 24, puis à déballaster progressivement la plate-forme, jusqu'à ce que la collerette 50 vienne en appui sur le siège 48, ainsi que représenté sur la figure 5D. La plate-forme 10 est ainsi remontée de l'intervalle K'. Lors du déballastage, le derrick 18 est progressivement relâché pour permettre un déplacement relatif entre la colonne montante et la plate-forme.The next phase of the process first involves linking the mechanism head pull 30 to the riser 24, then gradually unpack the platform, until the flange 50 comes to bear on the seat 48, as shown in Figure 5D. The platform 10 is thus raised by the interval K '. During deballasting, the derrick 18 is gradually released to allow relative movement between the riser and the platform.

    Lors du déballastage ultérieur de la plate-forme, le flotteur se dégage des butées 60 puisque celui-ci est retenu par la colonne montante 24. Ainsi, comme représenté sur la figure 5E, la plate-forme poursuit sa remontée jusqu'à sa position d'exploitation alors que le flotteur 28 reste à une profondeur constante. Cette seconde phase de remontée correspond à un intervalle l-K' de hauteur égale à environ 1 m.During the subsequent deballasting of the platform, the float is released stops 60 since this is retained by the riser 24. Thus, as shown in FIG. 5E, the platform continues its raised to its operating position while the float 28 remains at constant depth. This second ascent phase corresponds at an interval l-K 'of height equal to approximately 1 m.

    Dans cette position, le flotteur 28 exerce une force de rappel vers la surface de la partie basse de la colonne montante.In this position, the float 28 exerts a restoring force towards the surface of the lower part of the riser.

    Après décollement du flotteur 28 des butées 60, ces dernières sont escamotées pour permettre un débattement vertical maximal du flotteur par rapport à l'embase 16.After detachment of the float 28 from the stops 60, the latter are retracted to allow maximum vertical float travel relative to the base 16.

    De même, les moyens de traction de tête 30 sont actionnés afin d'assurer la traction du tronçon supérieur de la colonne montante 24 compris entre le derrick 18 et le flotteur 28.Likewise, the head traction means 30 are actuated so as to ensure the traction of the upper section of the riser 24 included between the derrick 18 and the float 28.

    On comprend que du fait de la hauteur du flotteur, celui-ci est susceptible d'effectuer des débattements de grande amplitude par rapport à l'embase 16 de la plate-forme, tout en étant convenablement guidé par les moyens de guidage latéraux 40.We understand that because of the height of the float, it is likely perform large amplitude deflections compared to the base 16 of the platform, while being suitably guided by the lateral guide means 40.

    Un autre procédé de mise en place d'une colonne montante d'une installation selon l'invention est illustré aux figures 6A à 6D.Another method of placing a riser in a installation according to the invention is illustrated in FIGS. 6A to 6D.

    Pour la mise en oeuvre de ce procédé, la coque 12 de la plate-forme est équipée de treuils 90 permettant de suspendre un lest annulaire 92 au-dessus du flotteur 28. Le lest annulaire 92 est formé de deux demi-anneaux assemblés autour de la colonne montante 24. La longueur du treuil est suffisante pour déposer le lest 92 sur la surface annulaire supérieure du flotteur 28. De plus, le poids du lest 92 est adapté pour assurer l'enfoncement du flotteur 28 vers le fond.For the implementation of this process, the hull 12 of the platform is equipped with 90 winches for hanging an annular ballast 92 above the float 28. The annular ballast 92 is formed by two half-rings assembled around the riser 24. The length of the winch is sufficient to deposit ballast 92 on the upper annular surface of the float 28. In addition, the weight of the ballast 92 is adapted to ensure the insertion of the float 28 towards the bottom.

    Comme dans le mode de réalisation précédent, la colonne montante 24 est immergée avec son extrémité inférieure maintenue à distance du fond F. Lors de cette mise en place de la colonne montante, le flotteur 28 est en butée contre les pennes 64.As in the previous embodiment, the riser 24 is submerged with its lower end held at a distance of the bottom F. During this installation of the riser, the float 28 is in abutment against the pins 64.

    Le lest 92 est ensuite acheminé jusque sur le flotteur. Ainsi, le flotteur 28 est amené à s'enfoncer comme représenté sur la figure 6B,.The ballast 92 is then conveyed as far as the float. So the float 28 is caused to sink as shown in Figure 6B ,.

    Après un enfoncement suffisant du flotteur 28, la colonne montante est descendue et son extrémité inférieure est connectée sur un puits d'exploitation de pétrole ainsi que représenté sur la figure 6C. Du fait de l'enfoncement du flotteur 28, la collerette 50 de la colonne montante est écartée du siège 48. Dans ces conditions, la colonne montante 24 est détendue, ce qui permet sa connexion au puits d'exploitation.After sufficient insertion of the float 28, the riser is lowered and its lower end is connected to an operating well of oil as shown in Figure 6C. Because of the depression of float 28, the collar 50 of the riser is away from the seat 48. Under these conditions, the riser 24 is relaxed, allowing its connection to the operating well.

    Après connexion de l'extrémité inférieure de la colonne montante, le lest 92 est remonté, comme représenté sur la figure 6D. La butée assurée par le verrou 60 ayant été dégagée, le flotteur 28 tend à remonter à la surface, de sorte qu'il exerce sur la colonne montante 24 une force de traction ascendante appliquée sur la collerette 50.After connecting the lower end of the riser, the ballast 92 is raised, as shown in FIG. 6D. The guaranteed stop by the latch 60 having been released, the float 28 tends to rise to the surface, so that it exerts on the riser 24 a force of upward traction applied on the flange 50.

    Suivant ce procédé d'implantation d'une colonne montante mettant en oeuvre un lest, il n'est pas nécessaire de lester la plate-forme ou le flotteur, évitant ainsi les transferts d'eau de mer.According to this method of implantation of a riser putting using a ballast, it is not necessary to ballast the platform or the float, thus avoiding sea water transfers.

    Claims (12)

    Installation d'exploitation d'un gisement en mer, du type comportant une plate-forme semi-submersible (10), au moins une colonne montante (24) reliant la plate-forme (10) au fond marin F, et des moyens (28,30) de mise sous tension de ladite colonne montante (24), caractérisée en ce que les moyens de mise sous tension comportent, pour la ou chaque colonne montante (24), au moins un flotteur (28) immergé, relié en un point de la partie courante de la colonne montante (24) pour sa traction vers la surface, et un mécanisme (30) de traction de la colonne montante (24), lequel mécanisme (30) est installé sur la plate-forme (10) et appliqué en tête de la colonne montante (24), et en ce qu'elle comporte des moyens (60) de mise en butée du flotteur (28) contre la plate-forme (10), suivant le sens ascendant.Installation for exploiting a deposit at sea, of the type comprising a semi-submersible platform (10), at least one column riser (24) connecting the platform (10) to the seabed F, and means (28,30) for tensioning said riser (24), characterized in that the tensioning means include, for the or each riser (24), at least one submerged float (28), connected at a point in the current part of the riser (24) for its traction towards the surface, and a mechanism (30) for pulling the riser (24), which mechanism (30) is installed on the platform (10) and applied at the head of the riser (24), and in that it comprises means (60) for abutting the float (28) against the platform (10), following the ascending direction. Installation selon la revendication 1, caractérisée en ce que le ou chaque flotteur (28) est dimensionné pour appliquer sur la colonne montante (24), une force de traction supérieure à la force de traction appliquée par le mécanisme (30) de traction de tête.Installation according to claim 1, characterized in that the or each float (28) is sized to apply to the column rising (24), a traction force greater than the applied traction force by the head traction mechanism (30). Installation selon la revendication 1 ou 2, caractérisée en ce que le flotteur (28) est dimensionné pour appliquer sur la colonne montante (24) une force de traction comprise entre 1 et 3 fois le poids de la colonne montante (24).Installation according to claim 1 or 2, characterized in that the float (28) is sized to apply to the riser (24) a tensile force between 1 and 3 times the weight of the column rising (24). Installation selon l'une quelconque des revendications précédentes, caractérisée en ce que la plate-forme (10) comporte une embase immergée (16) et une coque émergée (12) reliée par des jambes (14), le ou chaque flotteur (28) étant disposé à la profondeur de ladite embase (16), laquelle embase comporte des moyens (40) de guidage vertical du ou de chaque flotteur (28).Installation according to any one of the preceding claims, characterized in that the platform (10) has a base submerged (16) and an emerged shell (12) connected by legs (14), the or each float (28) being disposed at the depth of said base (16), which base includes means (40) for vertical guidance of the or of each float (28). Installation selon la revendication 4, caractérisée en ce que l'embase (16) comporte, pour chaque flotteur (28), un passage vertical (22) au travers duquel le flotteur (28) est mobile axialement.Installation according to claim 4, characterized in that the base (16) comprises, for each float (28), a vertical passage (22) through which the float (28) is axially movable. Installation selon l'une quelconque des revendications précédentes, caractérisée en ce que le ou chaque flotteur (28) présente un conduit traversant (32) dans lequel s'étend la colonne montante associée (24).Installation according to any one of the preceding claims, characterized in that the or each float (28) has a through duct (32) in which the associated riser extends (24). Installation selon l'une quelconque des revendications précédentes, caractérisée en ce que les moyens assurant la liaison entre le ou chaque flotteur (28) et la colonne montante (24) associée comporte une rotule (46).Installation according to any one of the preceding claims, characterized in that the means ensuring the connection between the or each float (28) and the associated riser (24) has a ball joint (46). Installation selon les revendications 6 et 7 prises ensemble, caractérisée en ce que la rotule comporte un siège annulaire concave (48) solidarisé audit flotteur (28) dans le conduit axial (32) et une collerette (50) à surface convexe (56) portée par la colonne montante (24), la collerette (50) étant appliquée contre le siège concave (48) pour l'application de la traction sur la colonne montante (24).Installation according to claims 6 and 7 taken together, characterized in that the ball joint has a concave annular seat (48) secured to said float (28) in the axial duct (32) and a flange (50) with a convex surface (56) carried by the riser (24), the flange (50) being applied against the concave seat (48) for the application of the traction on the riser (24). Installation selon la revendication 6, caractérisée en ce que le conduit traversant (32) a un diamètre supérieur à trois fois le diamètre de la colonne montante (24).Installation according to claim 6, characterized in that the through conduit (32) has a diameter greater than three times the diameter of the riser (24). Installation selon l'une quelconque des revendications précédente, caractérisée en ce que le mécanisme de traction de tête (30) comporte au moins un vérin hydropneumatique (70) comportant à chaque extrémité un ensemble de poulies mouflées (72, 74) sur lesquelles est engagé au moins un brin (76) de traction appliqué à ladite colonne montante (24).Installation according to any one of the preceding claims, characterized in that the head traction mechanism (30) has at least one hydropneumatic cylinder (70) comprising at each end a set of reeved pulleys (72, 74) on which is engaged at least one traction strand (76) applied to said riser (24). Procédé d'implantation d'une colonne montante (24) d'une installation selon la revendication 1, caractérisé en ce qu'il comporte les étapes successives consistant à: a - assurer la mise en butée verticale du flotteur (28) contre la plate-forme (10); b - immerger la colonne montante (24) avec son extrémité inférieure maintenue à distance du fond marin F; c- ballaster la plate-forme (10); d- descendre la colonne montante (24) et relier celle-ci au fond marin F; e - dégager la butée entre le flotteur (28) et la plate-forme (10); et f- déballaster la plate-forme (10). Method for installing a riser (24) of an installation according to claim 1, characterized in that it comprises the successive steps consisting in: a - ensuring the vertical abutment of the float (28) against the platform (10); b - immerse the riser (24) with its lower end kept away from the seabed F; c- ballaster the platform (10); d- lower the riser (24) and connect it to the seabed F; e - clear the stop between the float (28) and the platform (10); and f- unpack the platform (10). Procédé d'implantation d'une colonne montante (24) d'une installation selon la revendication 1, caractérisé en ce qu'il comporte les étapes consistant à: a - assurer la mise en butée du flotteur (28) contre la plate-forme (10); b - immerger la colonne montante (24) avec son extrémité inférieure maintenue à distance du fond marin F; c - enfoncer vers le bas le flotteur (28) par mise en place d'un lest (92) sur le flotteur (28); d - descendre la colonne montante (24) et relier celle-ci au fond marin (F), e - dégager la butée entre le flotteur (28) et la plate-forme (10); et f - retirer le lest (92) pesant sur le flotteur (28). Method for installing a riser (24) of an installation according to claim 1, characterized in that it comprises the steps consisting in: a - ensuring the abutment of the float (28) against the platform (10); b - immerse the riser (24) with its lower end kept away from the seabed F; c - press down the float (28) by placing a ballast (92) on the float (28); d - lower the riser (24) and connect it to the seabed (F), e - clear the stop between the float (28) and the platform (10); and f - remove the ballast (92) weighing on the float (28).
    EP99402019A 1998-08-11 1999-08-09 Installation for the exploitation of an offshore oil deposit and method for mounting a riser Expired - Lifetime EP0979923B1 (en)

    Applications Claiming Priority (2)

    Application Number Priority Date Filing Date Title
    FR9810301A FR2782341B1 (en) 1998-08-11 1998-08-11 INSTALLATION FOR OPERATING A DEPOSIT AT SEA AND METHOD FOR ESTABLISHING A COLUMN
    FR9810301 1998-08-11

    Publications (2)

    Publication Number Publication Date
    EP0979923A1 true EP0979923A1 (en) 2000-02-16
    EP0979923B1 EP0979923B1 (en) 2005-01-12

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    EP99402019A Expired - Lifetime EP0979923B1 (en) 1998-08-11 1999-08-09 Installation for the exploitation of an offshore oil deposit and method for mounting a riser

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    EP (1) EP0979923B1 (en)
    AU (1) AU754800C (en)
    BR (1) BR9904472A (en)
    CA (1) CA2280399C (en)
    EA (1) EA001520B1 (en)
    FR (1) FR2782341B1 (en)
    ID (1) ID25956A (en)
    NO (1) NO315529B1 (en)

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    Also Published As

    Publication number Publication date
    AU754800B2 (en) 2002-11-28
    CA2280399A1 (en) 2000-02-11
    CA2280399C (en) 2007-10-02
    AU754800C (en) 2003-06-12
    FR2782341A1 (en) 2000-02-18
    NO993852L (en) 2000-02-14
    US6406223B1 (en) 2002-06-18
    ID25956A (en) 2000-11-16
    EP0979923B1 (en) 2005-01-12
    NO993852D0 (en) 1999-08-10
    US20020048492A1 (en) 2002-04-25
    EA001520B1 (en) 2001-04-23
    AU4347799A (en) 2000-03-02
    US6347912B1 (en) 2002-02-19
    NO315529B1 (en) 2003-09-15
    FR2782341B1 (en) 2000-11-03
    BR9904472A (en) 2000-08-29
    EA199900640A3 (en) 2000-04-24
    EA199900640A2 (en) 2000-02-28

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