EP0979921B1 - Method for installing an oil production installation - Google Patents

Method for installing an oil production installation Download PDF

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Publication number
EP0979921B1
EP0979921B1 EP99402018A EP99402018A EP0979921B1 EP 0979921 B1 EP0979921 B1 EP 0979921B1 EP 99402018 A EP99402018 A EP 99402018A EP 99402018 A EP99402018 A EP 99402018A EP 0979921 B1 EP0979921 B1 EP 0979921B1
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EP
European Patent Office
Prior art keywords
seabed
riser
point
intervention
free end
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 - Lifetime
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EP99402018A
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German (de)
French (fr)
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EP0979921A1 (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 EP0979921A1 publication Critical patent/EP0979921A1/en
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    • 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
    • E21B7/00—Special methods or apparatus for drilling
    • E21B7/04—Directional drilling
    • E21B7/043—Directional drilling for underwater installations
    • 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
    • E21B33/00—Sealing or packing boreholes or wells
    • E21B33/02—Surface sealing or packing
    • E21B33/03—Well heads; Setting-up thereof
    • E21B33/068—Well heads; Setting-up thereof having provision for introducing objects or fluids into, or removing objects from, wells
    • E21B33/076—Well heads; Setting-up thereof having provision for introducing objects or fluids into, or removing objects from, wells specially adapted for underwater installations
    • 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

  • the present invention relates to an intervention method in a set separate intervention points spread over the seabed from the free end of the same riser from a semi-submersible platform suitable for the exploitation of a deposit.
  • Semi-submersible platforms are intended for exploitation petroleum in deep seas or oceans (see US-A-4,174,011). They include a shell supported by legs, the lower part of which is connected to a base dig. The base and buoyancy boxes arranged in the legs ensure the buoyancy and stability of the platform. The shell attached to the legs is kept above the sea surface when operating installation.
  • the platform In order to collect the extracted hydrocarbons, the platform is connected to the seabed by several rising columns. These are connected to a set of wells drilled to the right of the platform.
  • These wells are generally distributed around the periphery of a central point for example on a circle having a diameter of about 40m.
  • the platform is equipped with a single column rising drilling. It has an outer tube generally having a diameter of 20 inches (50.8cm) in which organs of drilling such as a drill bit.
  • the wells are distributed around the periphery of a planned storage point on the bottom in the center of the deposit.
  • the storage point is generally defined by the English term "parking slot”. It has a connector installed on the bottom which allows the temporary immobilization of the riser.
  • the wells are drilled one after the other around the storage point.
  • the platform is moved from one borehole to another, so that the upper part of the riser is located substantially at the vertical of the drilling in progress.
  • the displacement of the platform for drilling the various wells is a long and delicate operation, since it is suitable after each drilling to undock the platform, move it, and then re-anchor it right of the chosen intervention point.
  • the object of the invention is to propose an intervention method on the seabed thanks to a riser allowing to realize quickly and easily drilling or operating multiple wells from a single platform.
  • an oil platform is schematically represented self-elevating 10 semi-submersible type. It is arranged in a region of great depth, this being for example equal to 1300 meters.
  • the platform essentially comprises an upper shell 12 extending above the surface M of the sea when the platform is in operating phase.
  • the shell 12 is connected, by four legs 14 provided with buoyancy boxes, with a submerged lower base 16.
  • the upper hull includes technical residential buildings not represented as well than a derrick 18.
  • the shell 12 and the base 16 are both square in shape and have in their center, conduits 20, 22 visible in FIGS. 2 and 3.
  • conduits 20, 22 are arranged below the derrick 18 and are adapted for the passage of risers designated by the general reference 24. These risers are adapted as appropriate either for drilling operating wells, ie for the actual exploitation of petroleum.
  • the upper shell 12 includes pinion mechanisms 26 and racks for lowering the legs 14 and hoisting the hull 12 above from the surface of the water.
  • the mechanisms 26 also include locking means legs 14 relative to the shell 12 to ensure a rigid connection of legs on the hull.
  • mooring lines 28 kept under tension are installed between the submerged base 16 and the seabed to immobilize the platform above the deposit.
  • Figure 1 are schematically illustrated successive steps the establishment of an oil well.
  • the installation method of the installation comprises an initial step consisting in mooring the platform 10 in line with the deposit to immobilize it in buoyancy in relation to the seabed noted F.
  • This mooring is carried out as known per se by installation of the mooring lines 28.
  • riser drill 24 While the shell 12 is held above the surface M of the sea, the buoyancy and stability of the platform being ensured by the base 16 and the boxes arranged in the legs, a riser drill 24 is setup.
  • the riser pipe is generally designated by the English term "riser”.
  • This duct is located exactly vertically derrick.
  • the first conduit 30 is drilled and entubed II is equipped with a connector for the free end of the riser pipe 24 in order to establish a storage point thereof.
  • the riser 24 is stored by being connected to the point of storage 30. It is then kept energized by a mechanism adapted installed on the platform.
  • Drill riser 24 in its storage position at point 30 is shown in phantom in Figure 1.
  • the free end of the column 24 is then moved relative to the bottom F, for example in the direction of arrow F1, to be brought to a second point of intervention where a then must be drilled.
  • the floating platform is maintained in place, almost immobile relative to the seabed F.
  • a well noted 32 is installed and drilled.
  • the riser 24 In its second position, where it is used for drilling the well 32, the riser 24 is shown in solid lines in FIG. 1
  • FIG. 2 shows a first method of moving the the free end of the riser 24.
  • three self-propelled submersible vehicles 34,36,38 are deposited on the seabed F, for example via a crane 40 installed on the hull of platform 10. These submersible vehicles 34, 36 and 38 are deposited around the surface occupied by the platform. In Indeed, the shell 10 and the base 16 are devoid of sufficient opening wide to allow the passage of self-propelled vehicles.
  • Vehicles 34, 36 and 38 are for example provided with hydraulically powered track drive.
  • the hydraulic pressure required their movement is provided by an autonomous submersible device 42 remotely controlled and connected to platform 10 by an umbilical cord 44.
  • Au across cord 44 are transported control information and energy power required.
  • each of the vehicles self-propelled 34,36,38 is transported, in turn, from the region where it was deposited on the ground by crane 40 to a selected anchor point located below the surface occupied by platform 10.
  • Vehicles 34,36,38 are shown at their respective anchor points where they are designated respectively by the references 34a, 36a, 38a. These anchor points are located outside the area to be occupied by the operating wells, but immediately on the outskirts thereof.
  • the self-propelled vehicles thus anchored constitute fixed points, or dead bodies immobilized on the seabed. They provide a feedback for the application of traction on the lower end of the column rising 24.
  • traction means 46, 48, 50 are installed between each fixed point thus formed and the free end of the column rising 24.
  • These traction means consist for example of a winch carried by an autonomous submersible machine controlled and powered from the platform through an umbilical cord.
  • the traction means 46, 48, 50 are carried by each of the submersible devices 34, 36, 38.
  • the traction means 46, 48, 50 each comprise on the one hand, means of attachment to one of the fixed points and on the other hand hooking means at the free end of the riser 24. These attachment means are controlled from the surface through the cord umbilical connecting each submersible device.
  • the free end of the riser 24 is moved under the combined actions of the means of traction 46,48,50 applying coplanar traction forces on it and not coaxial. We can see that under the action of these three forces, the free end riser 24 can be routed to one of the sampling points planned, and distributed on a circle noted 52 having for center the point of storage 30.
  • the free end of the riser 24 is moved successively so similar to the other sampling points distributed on the circle 52.
  • the drilling riser 24 can, between each new drilling, be stored temporarily by being connected to storage point 30.
  • FIGS 3 and 4 illustrate another mode of movement of the end free from riser 24.
  • anchors to suction 60 forming anchor points are arranged at the four corners of a square of approximately 50 meters side surrounding the circle noted 62 on which must be distributed the peripheral wells.
  • tensioned links 64 extending over the seabed F. These links 64 are for example formed of chains attached to the anchors 60.
  • mooring strands 66 are distributed at regular intervals, mooring strands 66 one end of which is connected to the links 64 and the other end of which is provided with a floating buoy 68.
  • These mooring strands 66 have by example a length of 3 meters and are formed of a section of chain. They constitute fixed points in relation to the seabed, since they are carried by the links 64, themselves mobilized on the bottom by the anchors 60.
  • the anchors 60 being located at the corners of a square in which is inscribed the circle 62, the fixed points 66 are distributed on the sides of the square outside of the well implantation region.
  • suction anchors are replaced by bodies dead, conventional anchors or stakes.
  • traction means 70 carried by autonomous submersible machines, are connected on the one hand to the free end of the riser 24 and on the other hand, with three mooring strands separate 66.
  • the combined action of the three traction means allows displacement from the free end of the riser 24 in order to move it between the different wells to be drilled.
  • suction anchors 60 and the mooring strands 66 are installed on the deposit before the installation of the platform 10.
  • FIGS 5 and 6 means 78 for recalling the free end of the riser 24.
  • These return means comprise a cable 80 slidably mounted inside a sheath 82 extending along the submerged part of the riser 24.
  • the sheath 82 is retained against the riser 24 by collars 84 distributed at regular intervals over the whole the length of column 24.
  • the lower end of the cable 80 is fixed to the seabed for example in the immediate vicinity of the storage point 30 located in the center of the assembly Wells.
  • the upper end of the cable 80 is connected to the traction means not shown provided on the hull 12 of the platform.
  • On the hull 12 is further provided a winch on which are wound both the sheath 82 and the cable 80 contained therein. This winch makes it possible to unwind the sheath 82 and the cable during installation of column 24.
  • the cable 80 By exerting on the cable 80, traction from the traction means provided on the hull, the cable 80 slides in the sheath 82 and ensures the return from the riser 24 to the storage point 30. The riser is then in line with the storage point 30 as shown in the figure 5.
  • the return means 78 thus arranged along the riser 24, prevent the free end of it does not come out of the region in which the wells are to be distributed
  • FIG. 7 shows another variant of implementation of the method of moving the lower end of the riser 24 from storage point 30 to sampling point 32.
  • the free end of the riser 24 is connected to the end of two moorings 90, 92 in length predetermined.
  • the moorings 90. 92 are fixed respectively at points 94 and 96 on the seabed.
  • the attachment points of the moorings 94, 96 are arranged on the side and on the other side of the segment delimited by storage point 30 and the sampling point 32 towards which the free end of the mooring line 24 must be moved.
  • the anchor points 94, 96 of the moorings are placed substantially on the mediator of this segment.
  • the moorings 80, 82 are very slightly longer at the distance separating their respective anchor points from the points intervention 30 and 32.
  • the free end of the column riser 24 is kept confined in a mooring area 98 in the form of biconvex crescent bounded by the intersection of the two scanned disc sectors by the moorings 90, 92.
  • the axis of the biconvex crescent 98 extends substantially along the segment connecting points 30 and 32 due to the position of the moorings and their lengths.
  • the mooring area 98 is delimited in phantom by arcs of a circle defining the possible limit positions for the end of the riser. These arcs of a circle are centered at anchor points 94 and 96 and have radii denoted R 90 and R 92 respectively .
  • the free end of the riser 24 is linked by a cable 100 to traction means 102 anchored in the seabed.
  • the traction means 102 are arranged upstream of the end of the riser 24 considering the direction of the current symbolized by the arrow F7.
  • FIG. 8 shows a variant implementation of the method described with reference to FIG. 7 in which the anchor points of the moorings 90 and 92 are formed by exploitation wells, noted 94A, 96A, previously installed on circle 62.
  • the direction of the current tends to move the free end of column 24 towards the point intervention intervention 32.
  • the traction means 102 are placed at inside the space delimited by the circle 62. They thus oppose the drive of the riser 24 under the action of the designated sea current by arrow F4. To move the free end of the riser, the traction means 102 are gradually released until the free end of the riser reaches point 32.
  • the moorings 90 and 92 ensure the confinement of the free end of the riser in the biconvex mooring crescent 98, and its guidance to the target intervention point.
  • the method according to the invention can be used for displacement or the installation of operating columns, allowing pumping petrol.

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  • Geology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • Physics & Mathematics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Earth Drilling (AREA)
  • Underground Or Underwater Handling Of Building Materials (AREA)
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  • Connection Of Plates (AREA)

Description

La présente invention concerne un procédé d'intervention en un ensemble de points d'intervention distincts répartis sur le fond marin depuis l'extrémité libre d'une même colonne montante issue d'une plate-forme semi-submersible adaptée pour l'exploitation d'un gisement.The present invention relates to an intervention method in a set separate intervention points spread over the seabed from the free end of the same riser from a semi-submersible platform suitable for the exploitation of a deposit.

Les plates-formes semi-submersibles sont destinées à l'exploitation pétrolière dans des mers ou océans de grande profondeur (voir US-A- 4 174 011). Elles comportent une coque supportée par des jambes dont la partie inférieure est reliée à une embase creuse. L'embase et des caissons de flottabilité disposés dans les jambes assurent la flottabilité 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 petroleum in deep seas or oceans (see US-A-4,174,011). They include a shell supported by legs, the lower part of which is connected to a base dig. The base and buoyancy boxes arranged in the legs ensure the buoyancy and stability of the platform. The shell attached to the legs is kept above the sea surface when operating installation.

Afin de recueillir les hydrocarbures extraits, la plate-forme est reliée au fond marin par plusieurs colonnes montantes. Celles-ci sont connectées à un ensemble de puits forés au droit de la plate-forme.In order to collect the extracted hydrocarbons, the platform is connected to the seabed by several rising columns. These are connected to a set of wells drilled to the right of the platform.

Ces puits sont généralement répartis en périphérie d'un point central par exemple sur un cercle ayant un diamètre d'environ 40m.These wells are generally distributed around the periphery of a central point for example on a circle having a diameter of about 40m.

Avant l'implantation des colonnes montantes assurant l'exploitation du gisement, il convient de forer les différents puits auxquels seront connectées les colonnes montantes d'exploitation.Before the installation of risers ensuring the operation of the deposit, the various wells to which the operating risers.

Pour ce forage, la plate-forme est équipée d'une unique colonne montante de forage. Elle comporte un tube extérieur ayant généralement un diamètre de 20 pouces (50,8cm) dans lequel sont acheminés des organes de forage tels qu'un trépan.For this drilling, the platform is equipped with a single column rising drilling. It has an outer tube generally having a diameter of 20 inches (50.8cm) in which organs of drilling such as a drill bit.

Les puits sont répartis à la périphérie d'un point de stockage prévu sur le fond au centre du gisement. Le point de stockage est généralement défini par le terme anglais «parking slot». Il comporte un connecteur installé sur le fond qui permet l'immobilisation temporaire de la colonne montante. Les puits sont forés les uns après les autres autour du point de stockage.The wells are distributed around the periphery of a planned storage point on the bottom in the center of the deposit. The storage point is generally defined by the English term "parking slot". It has a connector installed on the bottom which allows the temporary immobilization of the riser. The wells are drilled one after the other around the storage point.

A cet effet, la plate-forme est déplacée d'un forage à l'autre, afin que la partie supérieure de la colonne montante de forage soit située sensiblement à la verticale du forage en cours de réalisation.For this purpose, the platform is moved from one borehole to another, so that the upper part of the riser is located substantially at the vertical of the drilling in progress.

Le déplacement de la plate-forme pour le forage des différents puits, constitue une opération longue et délicate, puisqu'il convient après chaque forage de désamarrer la plate-forme, de déplacer celle-ci, puis de la réamarrer au droit du point d'intervention choisi.The displacement of the platform for drilling the various wells, is a long and delicate operation, since it is suitable after each drilling to undock the platform, move it, and then re-anchor it right of the chosen intervention point.

L'invention a pour but de proposer un procédé d'intervention sur le fond marin grâce à une colonne montante permettant de réaliser rapidement et facilement le forage ou l'exploitation de plusieurs puits depuis une même plate-forme.The object of the invention is to propose an intervention method on the seabed thanks to a riser allowing to realize quickly and easily drilling or operating multiple wells from a single platform.

A cet effet, l'invention a pour objet un procédé d'intervention en un ensemble de points d'intervention distincts répartis sur le fond marin depuis l'extrémité libre d'une même colonne montante issue d'une plate-forme semi-submersible adaptée pour l'exploitation d'un gisement, caractérisé en ce qu'il comporte des étapes successives suivantes :

  • a) amarrer la plate-forme pour l'immobiliser en flottaison au droit du gisement ;
  • b) mettre en place la colonne montante reliant la plate-forme en flottaison au fond marin pour l'intervention en un premier point d'intervention ;
  • c) intervenir au premier point d'intervention ;
  • d) dégager l'extrémité libre de la colonne montante du premier point d'intervention, en maintenant celle-ci immergée;
  • e) déplacer l'extrémité libre de ladite colonne montante par rapport au fond marin vers un second point d'intervention, en maintenant en place la plate-forme en flottaison; et
  • f) intervenir au second point d'intervention.
    • To this end, the subject of the invention is a method of intervention at a set of separate intervention points distributed over the seabed from the free end of the same riser coming from a semi-submersible platform suitable for the exploitation of a deposit, characterized in that it comprises the following successive stages:
  • a) moor the platform to immobilize it in waterline at the level of the deposit;
  • b) set up the riser connecting the floating platform to the seabed for intervention at a first intervention point;
  • c) intervene at the first point of intervention;
  • d) clear the free end of the riser from the first point of intervention, keeping it submerged;
  • e) move the free end of said riser relative to the seabed to a second point of intervention, keeping the platform in place; and
  • f) intervene at the second intervention point.

    • Suivant des modes particuliers de mise en oeuvre, le procédé comporte une ou plusieurs des caractéristiques suivantes :

    • l'étape e) de déplacement de l'extrémité libre de la colonne montante comporte les étapes :
    • e1) d'installation préalable d'au moins un point fixe sur le fond marin
    • e2) de mise en place de moyens de traction entre l'extrémité libre de la colonne montante et le ou chaque point fixe ; et
    • e3) de traction de l'extrémité libre de ladite colonne montante à l'aide des moyens de traction reliés au ou à chaque point fixe associé, pour provoquer le déplacement par rapport au fond marin de ladite extrémité libre vers le second point d'intervention ;
    • il est prévu trois points fixes distincts non alignés, à chacun desquels sont reliés les moyens de traction assurant le déplacement de l'extrémité libre de la colonne montante sous l'action de trois forces non coaxiales ;
    • pour la mise en oeuvre de l'étape e), il comporte en outre l'étape consistant à lier l'extrémité libre de la colonne montante à au moins une amarre dont l'autre extrémité est fixée au fond marin en des emplacements tels que les premier et second points d'intervention sont situés dans le ou chaque secteur de disque balayé par la ou chaque amarre ;
    • l'extrémité libre de la colonne montante est liée à deux amarres qui sont fixées au fond marin de part et d'autre du segment délimité par les premier et second points d'intervention, la longueur des amarres étant choisie pour que ledit segment s'étende essentiellement suivant l'axe du croissant biconvexe défini par l'intersection des deux secteurs de disque balayés par les amarres ;
    • lesdits moyens de traction sont acheminés au fond par un engin submersible, et une fois au fond, ils sont reliés d'une part au ou à chaque point fixe associé et d'autre part, à l'extrémité libre de la colonne montante ;
    • le ou chaque point fixe est porté par un véhicule déplaçable sur le fond marin, lequel véhicule comporte des moyens d'ancrage sur le fond marin, et pour l'implantation du ou de chaque point fixe :
    • a) ledit véhicule est amené sur le fond à distance du point d'implantation retenu pour le point fixe ;
    • b) le véhicule est déplacé sur le fond jusqu'au point d'implantation retenu ; et
    • c) le véhicule est ancré au point d'implantation retenu.
    • le ou chaque point fixe est installé sur le fond avant l'amarrage de la plate-forme au droit du gisement, le ou chaque point fixe étant installé au-dessous de la surface occupée par la plate-forme ;
    • il est mis en place plusieurs points fixes reliés ensemble par des liens s'étendant sur le fond marin entre deux ancrages, lesquels liens sont disposés autour de la région du fond marin où se trouve l'ensemble des points d'intervention ;
    • des moyens de rappel de l'extrémité libre de la colonne montante sont installés entre celle-ci et le fond marin ;
    • les moyens de rappel sont adaptés pour assurer un rappel de l'extrémité libre de la colonne montante vers le centre de l'ensemble des points d'intervention ; et
    • les moyens de rappel comportent un câble coulissant dans une gaine s'étendant le long de la colonne montante, à laquelle elle est solidarisée, lequel câble relie le fond marin à la plate-forme, et le rappel de l'extrémité libre de la colonne montante vers le point de liaison du câble au fond marin est assuré par traction depuis la plate-forme du câble dans la gaine.
    According to particular modes of implementation, the method includes one or more of the following characteristics:
    • step e) of moving the free end of the riser comprises the steps:
    • e1) prior installation of at least one fixed point on the seabed
    • e2) setting up traction means between the free end of the riser and the or each fixed point; and
    • e3) of pulling the free end of said riser using the traction means connected to or to each associated fixed point, to cause the displacement with respect to the seabed of said free end towards the second point of intervention ;
    • three distinct non-aligned fixed points are provided, to each of which are connected the traction means ensuring the displacement of the free end of the riser under the action of three non-coaxial forces;
    • for the implementation of step e), it further comprises the step consisting in connecting the free end of the riser to at least one mooring line, the other end of which is fixed to the seabed in locations such as the first and second intervention points are located in the or each disc sector swept by the or each mooring;
    • the free end of the riser is linked to two moorings which are fixed to the seabed on either side of the segment delimited by the first and second intervention points, the length of the moorings being chosen so that said segment s' essentially extends along the axis of the biconvex crescent defined by the intersection of the two disc sectors swept by the moorings;
    • said traction means are conveyed to the bottom by a submersible device, and once at the bottom, they are connected on the one hand to or to each associated fixed point and on the other hand, to the free end of the riser;
    • the or each fixed point is carried by a vehicle movable on the seabed, which vehicle comprises anchoring means on the seabed, and for the implantation of the or each fixed point:
    • a) said vehicle is brought to the bottom at a distance from the location point chosen for the fixed point;
    • b) the vehicle is moved on the bottom to the chosen location point; and
    • c) the vehicle is anchored at the chosen installation point.
    • the or each fixed point is installed on the bottom before the mooring of the platform in line with the deposit, the or each fixed point being installed below the surface occupied by the platform;
    • it is set up several fixed points connected together by links extending on the seabed between two anchors, which links are arranged around the region of the seabed where all the intervention points are located;
    • means for returning the free end of the riser are installed between the latter and the seabed;
    • the return means are adapted to ensure a return from the free end of the riser towards the center of all the intervention points; and
    • the return means comprise a cable sliding in a sheath extending along the riser, to which it is secured, which cable connects the seabed to the platform, and the return of the free end of the column rising towards the point of connection of the cable to the seabed is ensured by traction from the cable platform in the sheath.

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

    • la Fig.1 est une vue en élévation d'une installation d'exploitation pétrolière en cours d'implantation ;
    • la Fig.2 est une vue schématique en perspective de trois quarts illustrant une phase d'implantation de l'installation suivant un premier mode de mise en oeuvre ;
    • la Fig.3 est une vue analogue à celle de la figure 2 illustrant une variante du procédé d'implantation de l'installation ;
    • la Fig.4 est une vue à plus grande échelle des moyens de la Fig.3 mis en oeuvre sur le fond ;
    • les Figs.5 et 6 sont des vues schématiques de l'extrémité inférieure de la colonne montante représentée respectivement en position retenue et en position relâchée ; et
    • les Figs.7 et 8 sont des vues de dessus illustrant deux variantes d'un autre procédé de déplacement de l'extrémité inférieure d'une colonne montante.
    The invention will be better understood with the aid of the description which follows, given solely by way of example and made with reference to the drawings, in which:
    • Fig.1 is an elevational view of an oil exploitation installation being implemented;
    • Fig.2 is a schematic perspective view of three quarters illustrating a phase of installation of the installation according to a first mode of implementation;
    • Fig.3 is a view similar to that of Figure 2 illustrating a variant of the installation process of the installation;
    • Fig.4 is a view on a larger scale of the means of Fig.3 implemented on the bottom;
    • Figs.5 and 6 are schematic views of the lower end of the riser shown respectively in the retained position and in the released position; and
    • Figs.7 and 8 are top views illustrating two variants of another method of moving the lower end of 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 égaie à 1300 mètres.In FIG. 1, an oil platform is schematically represented self-elevating 10 semi-submersible type. It is arranged in a region of great depth, this being for example equal to 1300 meters.

    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, 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 20,22 visibles sur les figures 2 et 3.The platform essentially comprises an upper shell 12 extending above the surface M of the sea when the platform is in operating phase. The shell 12 is connected, by four legs 14 provided with buoyancy boxes, with a submerged lower base 16. The upper hull includes technical residential buildings not represented as well than a derrick 18. The shell 12 and the base 16 are both square in shape and have in their center, conduits 20, 22 visible in FIGS. 2 and 3.

    Ces conduits 20,22 sont disposés au-dessous du derrick 18 et sont adaptés pour le passage de colonnes montantes désignées par la référence générale 24. Ces colonnes montantes sont adaptées suivant le cas soit pour le forage de puits d'exploitation, soit pour l'exploitation proprement dite du pétrole.These conduits 20, 22 are arranged below the derrick 18 and are adapted for the passage of risers designated by the general reference 24. These risers are adapted as appropriate either for drilling operating wells, ie for the actual exploitation of petroleum.

    La coque supérieure 12 comporte des mécanismes 26 à pignons et crémaillères permettant de descendre les jambes 14 et de hisser la coque 12 au-dessus de la surface de l'eau.The upper shell 12 includes pinion mechanisms 26 and racks for lowering the legs 14 and hoisting the hull 12 above from the surface of the water.

    Les mécanismes 26 comportent en outre des moyens de verrouillage des jambes 14 par rapport à la coque 12 afin d'assurer une liaison rigide des jambes sur la coque.The mechanisms 26 also include locking means legs 14 relative to the shell 12 to ensure a rigid connection of legs on the hull.

    Par ailleurs, des lignes d'amarrage 28 maintenues sous tension sont installées entre l'embase immergée 16 et le fond marin pour immobiliser la plate-forme au-dessus du gisement.Furthermore, mooring lines 28 kept under tension are installed between the submerged base 16 and the seabed to immobilize the platform above the deposit.

    Sur la figure 1 sont illustrées schématiquement des étapes successives de l'implantation d'un puits d'exploitation de pétrole.In Figure 1 are schematically illustrated successive steps the establishment of an oil well.

    Selon l'invention, le procédé d'implantation de l'installation comporte une étape initiale consistant à amarrer la plate-forme 10 au droit du gisement pour immobiliser celle-ci en flottaison par rapport au fond marin noté F.According to the invention, the installation method of the installation comprises an initial step consisting in mooring the platform 10 in line with the deposit to immobilize it in buoyancy in relation to the seabed noted F.

    Cet amarrage s'effectue comme connu en soi par installation des amarres sous tension 28.This mooring is carried out as known per se by installation of the mooring lines 28.

    Alors que la coque 12 est maintenue au-dessus de la surface M de la mer, la flottabilité et la stabilité de la plate-forme étant assurées par l'embase 16 et les caissons disposés dans les jambes, une colonne montante de forage 24 est mise en place. La colonne montante de forage est généralement désignée par le terme anglais " riser".While the shell 12 is held above the surface M of the sea, the buoyancy and stability of the platform being ensured by the base 16 and the boxes arranged in the legs, a riser drill 24 is setup. The riser pipe is generally designated by the English term "riser".

    La colonne montante de forage est descendue grâce au derrick 18 jusqu'au fond en un premier point d'intervention pour ie forage d'un premier conduit désigné par la référence 30. Ce conduit est situé exactement à la verticale du derrick. De manière connue en soi, le premier conduit 30 est foré et entubé II est équipé d'un connecteur pour l'extrémité libre de la colonne montante de forage 24 afin d'établir un point de stockage de celle-ci. En position de repos, la colonne montante de forage 24 est stockée en étant connectée au point de stockage 30. Elle est alors maintenue sous tension grâce à un mécanisme adapté installé sur la plate-forme.Drill riser lowered with derrick 18 to the bottom at a first point of intervention for the drilling of a first conduit designated by the reference 30. This duct is located exactly vertically derrick. In a manner known per se, the first conduit 30 is drilled and entubed II is equipped with a connector for the free end of the riser pipe 24 in order to establish a storage point thereof. In the rest position, the riser 24 is stored by being connected to the point of storage 30. It is then kept energized by a mechanism adapted installed on the platform.

    La colonne montante de forage 24 dans sa position de stockage au point 30 est représentée en trait mixte sur la figure 1.Drill riser 24 in its storage position at point 30 is shown in phantom in Figure 1.

    Après l'installation du point de stockage 30, l'extrémité libre de la colonne montante de forage 24 est dégagée du fond F. Celle-ci, est toutefois maintenue totalement immergée.After the installation of storage point 30, the free end of the column riser 24 is released from the bottom F. This, however, is kept fully submerged.

    L'extrémité libre de la colonne 24 est ensuite déplacée par rapport au fond F, par exemple suivant le sens de la flèche F1, pour être amenée jusqu'à un second point d'intervention où un puis doit être foré. Lors du déplacement de l'extrémité libre de la colonne, la plate-forme en flottaison est maintenue en place, quasi-immobile par rapport au fond marin F.The free end of the column 24 is then moved relative to the bottom F, for example in the direction of arrow F1, to be brought to a second point of intervention where a then must be drilled. When moving the free end of the column, the floating platform is maintained in place, almost immobile relative to the seabed F.

    Après que l'extrémité libre a atteint le second point d'intervention souhaité, un puits noté 32 est installé et foré.After the free end has reached the second desired point of intervention, a well noted 32 is installed and drilled.

    Dans sa seconde position, où elle est utilisée pour le forage du puits 32, la colonne montante 24 est représentée en trait plein sur la figure 1In its second position, where it is used for drilling the well 32, the riser 24 is shown in solid lines in FIG. 1

    Les mêmes étapes de dégagement sur l'extrémité libre de la colonne montante, de déplacement de celle-ci, vers un nouveau point de prélèvement et d'installation d'un nouveau puits de forage sont répétées pour l'ensemble de points de prélèvement. Les différents puits ainsi forés sont répartis sur un cercle centré sur le point de stockage 30.The same release steps on the free end of the column rising, moving it, to a new sampling point and installation of a new wellbore are repeated for the entire sampling points. The different wells drilled are distributed in a circle centered on storage point 30.

    Sur la figure 2, est illustré un premier procédé de déplacement de l'extrémité libre de la colonne montante de forage 24.FIG. 2 shows a first method of moving the the free end of the riser 24.

    Suivant ce procédé, trois véhicules submersibles auto-propulsés 34,36,38 sont déposés sur le fond marin F, par exemple par l'intermédiaire d'une grue 40 installée sur la coque de la plate-forme 10. Ces véhicules submersibles 34,36 et 38 sont déposés autour de la surface occupée par la plate-forme. En effet, la coque 10 et l'embase 16 sont dépourvues d'ouverture suffisamment large pour permettre le passage des véhicules auto-propulsifs.Following this process, three self-propelled submersible vehicles 34,36,38 are deposited on the seabed F, for example via a crane 40 installed on the hull of platform 10. These submersible vehicles 34, 36 and 38 are deposited around the surface occupied by the platform. In Indeed, the shell 10 and the base 16 are devoid of sufficient opening wide to allow the passage of self-propelled vehicles.

    Les véhicules 34,36 et 38 sont par exemple muni de mécanismes de propulsion à chenilles à actionnement hydraulique. La pression hydraulique nécessaire à leur déplacement est fournie par un engin submersible autonome 42 commandé à distance et relié à la plate-forme 10 par un cordon ombilical 44. Au travers du cordon 44 sont transportées des informations de commande et l'énergie d'alimentation nécessaire.Vehicles 34, 36 and 38 are for example provided with hydraulically powered track drive. The hydraulic pressure required their movement is provided by an autonomous submersible device 42 remotely controlled and connected to platform 10 by an umbilical cord 44. Au across cord 44 are transported control information and energy power required.

    Grâce à l'assistance de l'engin submersible 42, chacun des véhicules auto-propulsé 34,36,38 est acheminé, à son tour, de la région où il a été déposé sur le sol par la grue 40 jusqu'à un point d'ancrage retenu situé sous la surface occupée par la plate-forme 10.Thanks to the assistance of the submersible 42, each of the vehicles self-propelled 34,36,38 is transported, in turn, from the region where it was deposited on the ground by crane 40 to a selected anchor point located below the surface occupied by platform 10.

    Les véhicules 34,36,38 sont représentés à leur point d'ancrage respectif où ils sont désignés respectivement par les références 34a,36a,38a. Ces points d'ancrage sont situés à l'extérieur de la région devant être occupée par les puits d'exploitation, mais immédiatement à la périphérie de celle-ci.Vehicles 34,36,38 are shown at their respective anchor points where they are designated respectively by the references 34a, 36a, 38a. These anchor points are located outside the area to be occupied by the operating wells, but immediately on the outskirts thereof.

    Une fois acheminé sur les points d'ancrage retenus pour chaque véhicule auto-propulsé, ceux-ci sont immobilisés sur le fond marin, par exemple par l'intermédiaire de fourches 45 plantées dans le fond marin.Once routed to the anchor points selected for each vehicle self-propelled, these are immobilized on the seabed, for example by 45 forks planted in the seabed.

    Les véhicules auto-propulsés ainsi ancrés constituent des points fixes, ou corps morts immobilisés sur le fond marin. Ils permettent de fournir une contre-réaction pour l'application d'une traction sur l'extrémité inférieure de la colonne montante 24.The self-propelled vehicles thus anchored constitute fixed points, or dead bodies immobilized on the seabed. They provide a feedback for the application of traction on the lower end of the column rising 24.

    Après ancrage des véhicules, des moyens de traction 46,48,50 sont installés entre chaque point fixe ainsi formé et l'extrémité libre de la colonne montante 24. Ces moyens de traction sont constitués par exemple d'un treuil porté par un engin submersible autonome commandé et alimenté depuis la plate-forme au travers d'un cordon ombilical. En variante, les moyens de traction 46, 48, 50 sont portés par chacun des engins submersibles 34, 36, 38.After anchoring the vehicles, traction means 46, 48, 50 are installed between each fixed point thus formed and the free end of the column rising 24. These traction means consist for example of a winch carried by an autonomous submersible machine controlled and powered from the platform through an umbilical cord. Alternatively, the traction means 46, 48, 50 are carried by each of the submersible devices 34, 36, 38.

    Dans le cas présent, les moyens de traction 46,48,50 comportent chacun d'une part des moyens d'accrochage sur l'un des points fixes et d'autre part des moyens d'accrochage à l'extrémité libre de la colonne montante 24. Ces moyens d'accrochage sont commandés depuis la surface au travers du cordon ombilical reliant chaque engin submersible.In the present case, the traction means 46, 48, 50 each comprise on the one hand, means of attachment to one of the fixed points and on the other hand hooking means at the free end of the riser 24. These attachment means are controlled from the surface through the cord umbilical connecting each submersible device.

    Après mise en place des moyens de traction, l'extrémité libre de la colonne montante 24 est déplacée sous les actions combinées des moyens de traction 46,48,50 appliquant sur celle-ci, des forces de traction coplanaires et non coaxiales. On conçoit que sous l'action de ces trois forces, l'extrémité libre de la colonne montante 24 peut être acheminée jusqu'à l'un des points de prélèvement prévus, et répartis sur un cercle noté 52 ayant pour centre le point de stockage 30.After installation of the traction means, the free end of the riser 24 is moved under the combined actions of the means of traction 46,48,50 applying coplanar traction forces on it and not coaxial. We can see that under the action of these three forces, the free end riser 24 can be routed to one of the sampling points planned, and distributed on a circle noted 52 having for center the point of storage 30.

    Après installation du puits 32, et après un éventuel repositionnement des points fixes formés par les véhicules 34a,36a,38a ancrés sur le fond marin, l'extrémité libre de la colonne montante 24 est déplacée successivement de manière analogue jusqu'aux autres points de prélèvement répartis sur le cercle 52. La colonne montante de forage 24 peut, entre chaque nouveau forage, être entreposée temporairement en étant connectée au point de stockage 30.After installation of well 32, and after any repositioning fixed points formed by vehicles 34a, 36a, 38a anchored on the seabed, the free end of the riser 24 is moved successively so similar to the other sampling points distributed on the circle 52. The drilling riser 24 can, between each new drilling, be stored temporarily by being connected to storage point 30.

    Les figures 3 et 4 illustrent un autre mode déplacement de l'extrémité libre de la colonne montante 24.Figures 3 and 4 illustrate another mode of movement of the end free from riser 24.

    Suivant cette variante de mise en oeuvre du procédé, quatre ancres à succion 60 formant des points d'ancrage sont disposées aux quatre coins d'un carré de 50 mètres de côté environ entourant le cercle noté 62 sur lequel doivent être répartis les puits périphériques. Entre les ancres à succion 60 sont tendus des liens 64 s'étendant sur le fond marin F. Ces liens 64 sont par exemple formés de chaínes fixées aux ancres 60.According to this variant implementation of the method, four anchors to suction 60 forming anchor points are arranged at the four corners of a square of approximately 50 meters side surrounding the circle noted 62 on which must be distributed the peripheral wells. Between the suction anchors 60 are tensioned links 64 extending over the seabed F. These links 64 are for example formed of chains attached to the anchors 60.

    Sur la longueur des liens 64, sont répartis à intervalles réguliers, des brins d'amarrage 66 dont une extrémité est reliée aux liens 64 et dont l'autre extrémité est munie d'une bouée flottante 68. Ces brins d'amarrage 66 ont par exemple une longueur de 3 mètres et sont formés d'un tronçon de chaíne. Ils constituent des points fixes par rapport au fond marin, puisqu'ils sont portés par les liens 64, eux-mêmes mobilisés sur le fond par les ancres 60.Along the length of the links 64, are distributed at regular intervals, mooring strands 66 one end of which is connected to the links 64 and the other end of which is provided with a floating buoy 68. These mooring strands 66 have by example a length of 3 meters and are formed of a section of chain. They constitute fixed points in relation to the seabed, since they are carried by the links 64, themselves mobilized on the bottom by the anchors 60.

    Les ancres 60 étant situées aux coins d'un carré dans lequel est inscrit le cercle 62, les points fixes 66 sont répartis sur les côtés du carré à l'extérieur de la région d'implantation des puits.The anchors 60 being located at the corners of a square in which is inscribed the circle 62, the fixed points 66 are distributed on the sides of the square outside of the well implantation region.

    En variante, les ancres à succion sont remplacées par des corps morts, des ancres conventionnelles ou encore des pieux.Alternatively, the suction anchors are replaced by bodies dead, conventional anchors or stakes.

    Comme dans le mode de réalisation précédent, des moyens de traction 70, portés par des engins submersibles autonomes, sont reliés d'une part à l'extrémité libre de la colonne montante 24 et d'autre part, à trois brins d'amarrage distincts 66. As in the previous embodiment, traction means 70, carried by autonomous submersible machines, are connected on the one hand to the free end of the riser 24 and on the other hand, with three mooring strands separate 66.

    Ainsi, l'action combinée des trois moyens de traction permet le déplacement de l'extrémité libre de la colonne montante 24 afin de déplacer celle-ci entre les différents puits devant être forés.Thus, the combined action of the three traction means allows displacement from the free end of the riser 24 in order to move it between the different wells to be drilled.

    Avantageusement, les ancres à succion 60 et les brins d'amarrage 66 sont installés sur le gisement avant la mise en place de la plate-forme 10.Advantageously, the suction anchors 60 and the mooring strands 66 are installed on the deposit before the installation of the platform 10.

    Sur les figures 5 et 6 sont représentés des moyens 78 de rappel de l'extrémité libre de la colonne montante 24. Ces moyens de rappel comportent un câble 80 monté coulissant à l'intérieur d'une gaine 82 s'étendant le long de la partie immergée de la colonne montante 24. La gaine 82 est retenue contre la colonne montante 24 par des colliers 84 répartis à intervalles réguliers sur toute la longueur de la colonne 24.In Figures 5 and 6 are shown means 78 for recalling the free end of the riser 24. These return means comprise a cable 80 slidably mounted inside a sheath 82 extending along the submerged part of the riser 24. The sheath 82 is retained against the riser 24 by collars 84 distributed at regular intervals over the whole the length of column 24.

    L'extrémité inférieure du câble 80 est fixée au fond marin par exemple au voisinage immédiat du point de stockage 30 disposé au centre de l'ensemble des puits.The lower end of the cable 80 is fixed to the seabed for example in the immediate vicinity of the storage point 30 located in the center of the assembly Wells.

    L'extrémité supérieure du câble 80 est reliée à dés moyens de traction non représentés prévus sur la coque 12 de la plate-forme. Sur la coque 12 est en outre prévu un treuil sur lequel sont bobinés à la fois la gaine 82 et le câble 80 qui y est contenu. Ce treuil permet de dévider la gaine 82 et le câble lors de l'installation de la colonne 24.The upper end of the cable 80 is connected to the traction means not shown provided on the hull 12 of the platform. On the hull 12 is further provided a winch on which are wound both the sheath 82 and the cable 80 contained therein. This winch makes it possible to unwind the sheath 82 and the cable during installation of column 24.

    Avec un tel agencement, on conçoit, que comme représenté sur la figure 6, lorsque le câble 80 est détendu, la colonne montante 24 est entraínée, par exemple dans le sens de la flèche F 6 sous l'action du courant marin.With such an arrangement, it is understood that as shown in the FIG. 6, when the cable 80 is relaxed, the riser 24 is driven, for example in the direction of arrow F 6 under the action of the sea current.

    En exerçant sur le câble 80, une traction depuis les moyens de traction prévus sur la coque, le câble 80 coulisse dans la gaine 82 et assure le rappel de la colonne montante 24 vers le point de stockage 30. La colonne montante est alors au droit du point de stockage 30 comme représenté sur la figure 5.By exerting on the cable 80, traction from the traction means provided on the hull, the cable 80 slides in the sheath 82 and ensures the return from the riser 24 to the storage point 30. The riser is then in line with the storage point 30 as shown in the figure 5.

    Ainsi, en cas de courant violent, les moyens de rappel 78 ainsi disposés le long de la colonne montante 24, permettent d'éviter que l'extrémité libre de celle-ci ne sorte de la région dans laquelle les puits doivent être répartisThus, in the event of a strong current, the return means 78 thus arranged along the riser 24, prevent the free end of it does not come out of the region in which the wells are to be distributed

    Sur la figure 7 est représentée une autre variante de mise en oeuvre du procédé de déplacement de l'extrémité inférieure de la colonne montante 24 du point de stockage 30 au point de prélèvement 32. FIG. 7 shows another variant of implementation of the method of moving the lower end of the riser 24 from storage point 30 to sampling point 32.

    Sur cette figure sont représentés le point de stockage 30 de la colonne montante, le cercle 62 sur lequel sont répartis les points de forage, ainsi que l'extrémité libre de la colonne montante 24.In this figure are represented the storage point 30 of the column rising, the circle 62 on which the drilling points are distributed, as well than the free end of the riser 24.

    Dans cette variante de mise en oeuvre du procédé, l'extrémité libre de la colonne montante 24 est reliée à l'extrémité de deux amarres 90, 92 de longueur prédéterminée. A leur autre extrémité, les amarres 90. 92 sont fixées respectivement aux points 94 et 96 sur le fond marin.In this variant implementation of the method, the free end of the riser 24 is connected to the end of two moorings 90, 92 in length predetermined. At their other end, the moorings 90. 92 are fixed respectively at points 94 and 96 on the seabed.

    Les points de fixation des amarres 94, 96 sont disposés de part et d'autre du segment délimité par le point de stockage 30 et le point de prélèvement 32 vers lequel l'extrémité libre de l'amarre 24 doit être déplacée.The attachment points of the moorings 94, 96 are arranged on the side and on the other side of the segment delimited by storage point 30 and the sampling point 32 towards which the free end of the mooring line 24 must be moved.

    Les points d'ancrage 94, 96 des amarres sont placés sensiblement sur la médiatrice de ce segment.The anchor points 94, 96 of the moorings are placed substantially on the mediator of this segment.

    De plus, les amarres 80, 82 ont une longueur très légèrement supérieure à la distance séparant leurs points d'ancrage respectifs des points d'intervention 30 et 32.In addition, the moorings 80, 82 are very slightly longer at the distance separating their respective anchor points from the points intervention 30 and 32.

    Dans ces conditions, on comprend que l'extrémité libre de la colonne montante 24 est maintenue confinée dans une zone d'amarrage 98 en forme de croissant biconvexe délimité par l'intersection des deux secteurs de disque balayés par les amarres 90, 92. Avantageusement, l'axe du croissant biconvexe 98 s'étend sensiblement suivant le segment liant les points 30 et 32 du fait de la position des amarres et de leurs longueurs.Under these conditions, it is understood that the free end of the column riser 24 is kept confined in a mooring area 98 in the form of biconvex crescent bounded by the intersection of the two scanned disc sectors by the moorings 90, 92. Advantageously, the axis of the biconvex crescent 98 extends substantially along the segment connecting points 30 and 32 due to the position of the moorings and their lengths.

    Sur la figure 7, la zone d'amarrage 98 est délimitée en trait mixte par des arcs de cercle définissant les positions limites possibles pour l'extrémité de la colonne montante. Ces arcs de cercle sont centrés aux points d'ancrage 94 et 96 et ont des rayons notés respectivement R90 et R92.In FIG. 7, the mooring area 98 is delimited in phantom by arcs of a circle defining the possible limit positions for the end of the riser. These arcs of a circle are centered at anchor points 94 and 96 and have radii denoted R 90 and R 92 respectively .

    En outre, l'extrémité libre de la colonne montante 24 est liée par un câble 100 à des moyens de traction 102 ancrés dans le fond marin.In addition, the free end of the riser 24 is linked by a cable 100 to traction means 102 anchored in the seabed.

    Les moyens de traction 102 sont disposés en amont de l'extrémité de la colonne montante 24 en considérant le sens du courant symbolisé par la flèche F7.The traction means 102 are arranged upstream of the end of the riser 24 considering the direction of the current symbolized by the arrow F7.

    Avec une telle installation, lors de son transfert du point de stockage 30 au point d'intervention 32, l'extrémité libre de la colonne montante 24 est seulement soumise à la force des moyens de traction 102. Toutefois, celle-ci est maintenue dans le croissant biconcave 98, lequel présente une largeur progressivement décroissante en se rapprochant du second point d'intervention 32. Dans ces conditions, lors de sa traction, l'extrémité libre de la colonne montante 24 converge progressivement vers le point d'intervention 32, en y étant guidée par les amarres 90 et 92.With such an installation, when it is transferred from the storage point 30 at the intervention point 32, the free end of the riser 24 is only subjected to the force of the traction means 102. However, this is maintained in the biconcave crescent 98, which gradually widens decreasing closer to the second point of intervention 32. Under these conditions, when it is pulled, the free end of the riser 24 gradually converges towards intervention point 32, being guided there by moorings 90 and 92.

    Sur la figure 8 est représentée une variante de mise en oeuvre du procédé décrit en regard de la figure 7 dans lequel les points d'ancrage des amarres 90 et 92 sont formés par des puits d'exploitation, notés 94A, 96A, préalablement installés sur le cercle 62.FIG. 8 shows a variant implementation of the method described with reference to FIG. 7 in which the anchor points of the moorings 90 and 92 are formed by exploitation wells, noted 94A, 96A, previously installed on circle 62.

    Dans ce mode de réalisation, le sens du courant, représenté par la flèche F8, tend à déplacer l'extrémité libre de la colonne 24 vers le point d'intervention cible 32. Dans ce cas, les moyens de traction 102 sont placés à l'intérieur de l'espace délimité par le cercle 62. Ils s'opposent ainsi à l'entraínement de la colonne montante 24 sous l'action du courant marin désigné par la flèche F4. Pour le déplacement de l'extrémité libre de la colonne montante, les moyens de traction 102 sont progressivement relâchés jusqu'à ce que l'extrémité libre de la colonne montante atteigne le point 32.In this embodiment, the direction of the current, represented by the arrow F8, tends to move the free end of column 24 towards the point intervention intervention 32. In this case, the traction means 102 are placed at inside the space delimited by the circle 62. They thus oppose the drive of the riser 24 under the action of the designated sea current by arrow F4. To move the free end of the riser, the traction means 102 are gradually released until the free end of the riser reaches point 32.

    Comme précédemment, lors du relâchement progressif des moyens de traction 102, les amarres 90 et 92 assurent le confinement de l'extrémité libre de la colonne montante dans le croissant d'amarrage biconvexe 98, et son guidage vers le point d'intervention cible.As before, during the gradual relaxation of the means traction 102, the moorings 90 and 92 ensure the confinement of the free end of the riser in the biconvex mooring crescent 98, and its guidance to the target intervention point.

    Bien que la description qui précède porte sur le déplacement d'une colonne montante de forage, le procédé selon l'invention peut utilisé pour ie déplacement ou la mise en place de colonnes d'exploitation, permettant le pompage du pétrole.Although the foregoing description relates to the displacement of a riser for drilling, the method according to the invention can be used for displacement or the installation of operating columns, allowing pumping petrol.

    Claims (12)

    1. A method of intervention at a set of separate intervention points (30, 32) distributed on the seabed (F) from the free end of a single riser (24) leading from a semi-submersible platform (10) adapted for the exploitation of a deposit, characterised in that it comprises the following successive steps:
      a) tethering the platform (10) to immobilise it in a floating position vertically to the deposit;
      b) placing the riser (24) connecting the floating platform (10) to the seabed (F) for the intervention at a first intervention point (30);
      c) carrying out an intervention at the first intervention point (30);
      d) disengaging the free end of the riser (24) from the first intervention point (30), while keeping it submerged;
      e) moving the free end of said riser (24) in relation to the seabed (F) towards a second intervention point (32), while keeping the floating platform (10) in place; and
      f) carrying out an intervention at the second intervention point (32).
    2. The method according to Claim 1, characterised in that step e) for moving the free end of the riser (24) comprises the steps of:
      e1) preinstalling at least one fixed point (34a, 36a, 38a; 66) on the seabed (F);
      e2) placing pulling means (46, 48, 50; 70) between the free end of the riser (24) and the or each fixed point (34a, 36a, 38a; 66); and
      e3) pulling the free end of said riser (24) using the pulling means (46, 48, 50; 70) connected to the or each associated fixed point, so as to cause said free end to move in relation to the seabed (F) towards the second intervention point (32).
    3. The method according to claim 2, characterised in that three non-aligned separate fixed points (34a, 36a, 38a; 66) are provided, to each of which the pulling means (46, 48, 50; 70) providing for the movement of the free end of the riser (24) under the action of three non-coaxial forces are connected.
    4. The method according to claim 2, characterised in that, to implement step e), it further comprises the step of connecting the free end of the riser (24) to at least one tether (90, 92), the other end of which is fixed to the seabed (F) at locations such that the first and second intervention points (30, 32) are located in the or each disc sector swept by the or each tether (90, 92).
    5. The method according to Claim 4, characterised in that the free end of the riser (24) is connected to two tethers (90, 92) which are fixed to the seabed (F) on each side of the segment delimited by the first and second intervention points (30, 32), the length of the tethers (90, 92) being chosen such that said segment extends essentially along the axis of the biconvex crescent defined by the intersection of both disc sectors swept by the tethers (90, 92).
    6. The method according to any one of Claims 2 to 5, characterised in that said pulling means (46, 48, 50, 70) are transported to the seabed by a submersible machine, and once on the seabed, they are connected, on the one hand, to the or each associated fixed point (34a, 36a, 38a; 66) and, on the other, to the free end of the riser (24).
    7. The method according to any one of Claims 2 to 6, characterised in that the or each fixed point is carried by a vehicle moveable on the seabed (F), which vehicle (34) comprises means (45) for anchoring on the seabed, and in that, for the fitting of the or each fixed point:
      a) said vehicle is brought to the seabed (F) at a distance from the fitting point reserved for the fixed point;
      b) the vehicle is moved on the seabed (F) up to the reserved fitting point; and
      c) the vehicle is anchored to the reserved insertion point.
    8. The method according to any one of Claims 2 to 6, characterised in that the or each fixed point (66) is installed on the seabed (F) prior to the platform (10) being tethered vertically to the deposit, the or each fixed point (66) being installed underneath the surface occupied by the platform.
    9. The method according to Claim 8, characterised in that several fixed points (66) connected together by connections (64) extending on the seabed (F) between two anchors (60) are placed, which connections (64) are disposed around the region of the seabed (F) in which the set of intervention points lie.
    10. The method according to any one of the preceding claims, characterised in that return means (78) for the free end of the riser (24) are installed between the latter and the seabed (F).
    11. The method according to Claim 10, characterised in that the return means (78) are adapted to ensure return of the free end of the riser (24) towards the centre of the set of intervention points.
    12. The method according to Claim 10 or 11, characterised in that the return means (78) comprise a cable (80) sliding in a sheath (82) extending along the riser (24), with which it is made integral, which cable (80) connects the seabed (F) to the platform (10), and in that return of the free end of the riser (24) towards the connection point between the cable (80) and the seabed (F) is ensured by pulling from the platform (10) of the cable (80) into the sheath (82).
    EP99402018A 1998-08-11 1999-08-09 Method for installing an oil production installation Expired - Lifetime EP0979921B1 (en)

    Applications Claiming Priority (2)

    Application Number Priority Date Filing Date Title
    FR9810302A FR2782342B1 (en) 1998-08-11 1998-08-11 METHOD OF ESTABLISHING AN OPERATING FACILITY
    FR9810302 1998-08-11

    Publications (2)

    Publication Number Publication Date
    EP0979921A1 EP0979921A1 (en) 2000-02-16
    EP0979921B1 true EP0979921B1 (en) 2004-02-11

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    Family Applications (1)

    Application Number Title Priority Date Filing Date
    EP99402018A Expired - Lifetime EP0979921B1 (en) 1998-08-11 1999-08-09 Method for installing an oil production installation

    Country Status (9)

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    US (1) US6343655B1 (en)
    EP (1) EP0979921B1 (en)
    AU (1) AU754692B2 (en)
    BR (1) BR9903615A (en)
    CA (1) CA2280403C (en)
    EA (1) EA001885B1 (en)
    FR (1) FR2782342B1 (en)
    ID (1) ID23248A (en)
    NO (1) NO313894B1 (en)

    Families Citing this family (8)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    KR100712190B1 (en) 2005-12-29 2007-04-27 한국해양연구원 Apparatus and method for driving pile by hydraulic pressure
    KR100712191B1 (en) 2005-12-29 2007-04-27 한국해양연구원 Apparatus and method for driving pile by pile anchor and winch
    US9080393B2 (en) * 2012-05-31 2015-07-14 Transocean Sedco Forex Ventures Limited Drilling riser retrieval in high current
    US9404347B1 (en) * 2015-05-15 2016-08-02 Baker Hughes Incorporated Apparatus and method for connecting a riser from an offshore rig to a subsea structure
    US9719330B2 (en) * 2015-12-28 2017-08-01 Cameron International Corporation Subsea equipment pendulum arrestor and method for its use
    US9739101B1 (en) * 2016-07-13 2017-08-22 Ensco International Incorporated Riser deflection mitigation
    CN108001637B (en) * 2017-12-07 2019-07-23 吴林 Large-scale multiple groups close deep water and stablize floating platform waterborne
    CN115092352B (en) * 2022-07-11 2024-01-02 中船黄埔文冲船舶有限公司 Box girder hull layout structure and offshore wind power installation platform thereof

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    US4147221A (en) * 1976-10-15 1979-04-03 Exxon Production Research Company Riser set-aside system
    US4174011A (en) * 1977-09-12 1979-11-13 Standard Oil Company (Indiana) Subsea drilling template with carousel guidance system
    US4326595A (en) * 1980-04-25 1982-04-27 Texaco Development Corporation Method for drilling deviated wells into an offshore substrate
    US4754817A (en) * 1982-08-25 1988-07-05 Conoco Inc. Subsea well template for directional drilling
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    US4972907A (en) * 1985-10-24 1990-11-27 Shell Offshore Inc. Method of conducting well operations from a moveable floating platform

    Also Published As

    Publication number Publication date
    BR9903615A (en) 2000-09-05
    FR2782342A1 (en) 2000-02-18
    FR2782342B1 (en) 2000-11-10
    EA001885B1 (en) 2001-10-22
    ID23248A (en) 2000-03-30
    US6343655B1 (en) 2002-02-05
    AU4347899A (en) 2000-03-02
    NO993853L (en) 2000-02-14
    NO993853D0 (en) 1999-08-10
    EA199900639A3 (en) 2000-08-28
    CA2280403A1 (en) 2000-02-11
    AU754692B2 (en) 2002-11-21
    CA2280403C (en) 2007-10-02
    EA199900639A2 (en) 2000-02-28
    NO313894B1 (en) 2002-12-16
    EP0979921A1 (en) 2000-02-16

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