EP0963906B1 - Method for the installation of a gravity, self-elevating oil production platform at sea - Google Patents

Method for the installation of a gravity, self-elevating oil production platform at sea Download PDF

Info

Publication number
EP0963906B1
EP0963906B1 EP19990401357 EP99401357A EP0963906B1 EP 0963906 B1 EP0963906 B1 EP 0963906B1 EP 19990401357 EP19990401357 EP 19990401357 EP 99401357 A EP99401357 A EP 99401357A EP 0963906 B1 EP0963906 B1 EP 0963906B1
Authority
EP
European Patent Office
Prior art keywords
deck
platform
base
sub
columns
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
Application number
EP19990401357
Other languages
German (de)
French (fr)
Other versions
EP0963906A1 (en
Inventor
Dominique Michel
Philippe André Dumas
Vincent Frédéric Paul Foglia
Stanislas Jean Cyran
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
DORIS ENGINEERING
Original Assignee
DORIS ENGINEERING
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by DORIS ENGINEERING filed Critical DORIS ENGINEERING
Publication of EP0963906A1 publication Critical patent/EP0963906A1/en
Application granted granted Critical
Publication of EP0963906B1 publication Critical patent/EP0963906B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
    • B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING 
    • B63B35/00—Vessels or similar floating structures specially adapted for specific purposes and not otherwise provided for
    • B63B35/44—Floating buildings, stores, drilling platforms, or workshops, e.g. carrying water-oil separating devices
    • B63B35/4413—Floating drilling platforms, e.g. carrying water-oil separating devices
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B17/02—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto
    • E02B17/021—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto with relative movement between supporting construction and platform
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B2017/0052—Removal or dismantling of offshore structures from their offshore location
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B2017/0056—Platforms with supporting legs
    • E02B2017/0069—Gravity structures
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B2017/0056—Platforms with supporting legs
    • E02B2017/0073—Details of sea bottom engaging footing
    • E02B2017/0086—Large footings connecting several legs or serving as a reservoir for the storage of oil or gas

Definitions

  • the present invention relates to a method installation of a self-elevating gravity platform, designed in particular for the exploitation of a field tanker at sea and, more particularly, to such method of installing a platform of the type which includes a buoyant substructure consisting of a base and at least two columns projecting upwards of said base, and a buoyant bridge mounted on said columns.
  • the installation process of the platform described in the aforementioned patent is to tow a set floating consisting of the substructure and a hull deck buoyable mounted on it to the installation site final, to ballast the substructure to bring down this one towards the bottom while the hull deck floats at the water surface, to stop the ballasting of the substructure when the base reaches a depth predetermined and then block the hull deck on the base columns, then unpack the substructure until the hull deck is raised to a predetermined height above the water surface, and, finally, to connect the substructure to the seabed by anchor lines.
  • This installation process is particularly attractive in that it makes it possible to deploy the platform by the only deck buoyancy game and ballasting / deballasting of the substructure, which makes an implementation process particularly economical, especially since, moreover, the platform can be built entirely alongside or in dry dock.
  • the object of the present invention is precisely to provide a method of installing such a platform gravity on a medium depth oil field, which retains the economic advantages mentioned above of method of installing a semi-submersible platform "self-elevating" on a very deep field described in the aforementioned patent.
  • the present invention also aims to provide a platform designed for the implementation of this process, said platform comprising in particular, advantageously, storage means for products extracted from the field oil.
  • step c) the predetermined depth reached by the base is close to the sum of its air draft on the final installation site and the depth of the seabed on this site.
  • the platform shown essentially comprises a substructure 1 and a bridge 2.
  • the substructure 1 comprises a base 3 of rectangular plane and at least two, and in the example shown four, columns 4 i (i from 1 to 4) projecting upwards from the base 3, the bridge 2 being fixed to the upper end of these columns as shown in FIG. 1.
  • the substructure 1 represented is given only by way of illustrative and nonlimiting example. This is how that its base could just as well have a shape square, triangular, circular or other.
  • the base is intended to rest on the seabed 9. It takes the form of a parallelepipedic box advantageously comprising storage compartments for products extracted from the oil field and compartments ballasting / deballasting. These are used during the installation of the platform, as we will see further.
  • the base forms in operation a foundation of the platform ensuring the stability of this one by the simple effect weight as it is known in art.
  • Columns 4 i can be made from the same material as the base or from a different material. Their function is to support the bridge. They also delimit flotation compartments and can accommodate various so-called “utility” materials, such as pipes, pumps, various fluid reservoirs, etc.
  • the columns shown by way of example have a parallelepiped shape. They could also be of frustoconical or cylindrical shape for example. They each have a vertical face which faces the bridge 2 as shown in Figure 2 where it appears that a rectangular base 5 of the bridge 2 tangent to the four columns 4 i , inside a space delimited by them . This arrangement allows lateral guidance of the bridge by these columns, during the ballasting of the substructure, as will be seen below.
  • the bridge preferably has a structure metallic whose base 5 takes the form of a box, or hull, ensuring the buoyancy of the deck, hence the name deck-hull given to this type of deck. He wears classic equipment: derrick 6, crane 7, quarters 8, etc ... necessary for the execution of drilling of underwater wells, then upwelling products extracted from wells.
  • the bridge 2 is movable vertically with respect to the columns 4 i of the substructure 1, just like that of the jack-up platform described in the aforementioned patent, and therefore comprises means for lateral guidance at the interfaces between the base 5 of the bridge and the columns 4 i and of the means for locking the bridge on the columns.
  • locking means 10 1 , 10 2 there is shown very diagrammatically in FIG. 1 locking means 10 1 , 10 2 , the two other columns receiving identical locking means.
  • FIGS. 4A to 4H describe the installation process according to the invention of the platform of Figures 1 and 2.
  • FIG. 4A the substructure 1 is shown at the end of its construction in a dry dock 11, with a draft of the order of about fifteen meters for example.
  • FIG. 4B illustrates the impoundment of this dry dock, the substructure 1 then being placed in floatation.
  • a tugboat 12 pulls the substructure 1 out of the hold 11 to a site (FIG. 4C) where the deck 2 is placed on the base 3 of the substructure 1.
  • the deck 2, floating on its hull 5, is engaged between the columns 4 i of the substructure 1, suitably ballasted to allow the hull 5 to pass over the upper face of the base 3 of this substructure .
  • the base 3 is then deballasted (FIG. 4D) from so that the hull deck rests on the base and the sub-structure / deck-hull assembly can be towed to an intermediate sheltered site ( Figure 4E) of which, according to the invention, the seabed is deep higher than the bottom of the final installation site of the platform, for a reason that will appear in the after.
  • the ballasting of the base 3 is resumed, ensuring the descent of the substructure 1 and the floating hull deck 2.
  • the hydrostatic stability of the assembly is ensured by the buoyancy of the hull deck 2 on the water surface, the substructure 1 alone may not be stable in all the immersion phases.
  • the columns 4 i laterally guide the hull deck 2 during this descent, as described in the aforementioned patent.
  • the ballasting of the base 3 is stopped (FIG. 4F), the latter then having reached a predetermined depth substantially equal to the sum of the depth of the seabed of the final installation site of the platform (approximately 40 meters for example) and of the draft of the hull deck above the water, on this same final site (approximately 20 meters by example). This is why the depth of the bottom of the intermediate platform deployment site, at least 60 meters in the example given, must be greater than the depth of the final platform installation site.
  • the locking means 10 i are then actuated to prevent any further relative movement of the substructure 1 relative to the hull deck 2 (FIG. 4F).
  • the substructure is then deballasted to make raise the underside of the base 3 to a depth lower than that of the final installation site (Figure 4G) so as to allow towing of the platform to this site.
  • Figure 4H we ballast again the substructure until this one come to rest on the seabed 9, so as to ensure the stability of the platform on this background. In this position, deck 2 emerges over the water with the suitable air draft, set as explained above in link with FIG. 4F.
  • the platform could take the form from that shown in Figure 3 which does not differ from that Figures 1 and 2 that in that the bridge does not include hull and is therefore not independently buoyant.
  • the installation of this platform takes place substantially as described in connection with Figures 4A to 4H, at this except that Figure 4C 'should be substituted for Figure 4C.
  • the present invention achieves the goals set, namely to achieve a gravity platform designed to be installed in shallow water and retaining the economic benefits of self-elevating platforms for which on-site installation is achieved by the only game of the gravity and the buoyancy exerted on its constituents, without the use of lifting mechanisms expensive.
  • the installation of the fully equipped bridge on the structure also saves money heavy and expensive lifting means that are required in the case of installation of the bridge and the equipment in sea after the installation of the substructure on its final site operating.

Landscapes

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

Description

La présente invention est relative à un procédé d'installation d'une plate-forme gravitaire auto-élévatrice, conçue notamment pour l'exploitation d'un champ pétrolier en mer et, plus particulièrement, à un tel procédé d'installation d'une plate-forme du type qui comprend une sous-structure flottable constituée d'une embase et d'au moins deux colonnes débordant vers le haut de ladite embase, et un pont flottable monté sur lesdites colonnes.The present invention relates to a method installation of a self-elevating gravity platform, designed in particular for the exploitation of a field tanker at sea and, more particularly, to such method of installing a platform of the type which includes a buoyant substructure consisting of a base and at least two columns projecting upwards of said base, and a buoyant bridge mounted on said columns.

On a décrit dans la demande de brevet français N° 9715774 déposée le 12 décembre 1997 par la demanderesse, ci-après appelée brevet précité, une plate-forme présentant une structure de ce type, conçue pour être installée sur des champs pétroliers en mer de grande profondeur, de plusieurs centaines de mètres à 1500 m ou plus par exemple. La plate-forme est alors semi-submersible, flotte à la surface de l'eau et est mouillée par des lignes ancrées sur le fond marin.We have described in French patent application N ° 9715774 filed on December 12, 1997 by the plaintiff, hereinafter called the aforementioned patent, a platform presenting a structure of this type, designed to be installed on very deep offshore oil fields, several hundred meters to 1500 m or more for example. The platform is then semi-submersible, floats at the surface of the water and is wetted by lines anchored on the seabed.

Le procédé d'installation de la plate-forme décrit dans le brevet précité consiste à remorquer un ensemble flottant constitué par la sous-structure et un pont-coque flottable monté sur celle-ci jusqu'au site d'installation final, à ballaster la sous-structure pour faire descendre celle-ci vers le fond alors que le pont-coque flotte à la surface de l'eau, à arrêter le ballastage de la sous-structure quand l'embase atteint une profondeur prédéterminée et à bloquer alors le pont-coque sur les colonnes de l'embase, à déballaster ensuite la sous-structure jusqu'à ce que le pont-coque soit remonté à une hauteur prédéterminée au-dessus de la surface de l'eau, et, finalement, à raccorder la sous-structure au fond marin par des lignes d'ancrage. The installation process of the platform described in the aforementioned patent is to tow a set floating consisting of the substructure and a hull deck buoyable mounted on it to the installation site final, to ballast the substructure to bring down this one towards the bottom while the hull deck floats at the water surface, to stop the ballasting of the substructure when the base reaches a depth predetermined and then block the hull deck on the base columns, then unpack the substructure until the hull deck is raised to a predetermined height above the water surface, and, finally, to connect the substructure to the seabed by anchor lines.

Ce procédé d'installation est particulièrement attrayant en ce qu'il permet de déployer la plate-forme par le seul jeu de la flottabilité du pont et du ballastage/déballastage de la sous-structure, ce qui en fait un procédé de mise en oeuvre particulièrement économique, d'autant plus que, par ailleurs, la plate-forme peut être entièrement construite à quai ou en cale sèche.This installation process is particularly attractive in that it makes it possible to deploy the platform by the only deck buoyancy game and ballasting / deballasting of the substructure, which makes an implementation process particularly economical, especially since, moreover, the platform can be built entirely alongside or in dry dock.

On connaít aussi de la demande de brevet français n° 2.400.086 un procédé d'installation d'un pont sur les colonnes d'une structure gravitaire, suivant lequel on immerge la structure par ballastage et treuillage, de manière à placer le pont au-dessus des colonnes. Un déballastage de la structure met le pont hors d'eau. L'ensemble est remorqué ensuite vers son site final d'installation.We also know from French patent application n ° 2.400.086 a method of installing a bridge on the columns of a gravity structure, according to which the structure is immersed by ballasting and winching, so as to place the bridge over the columns. Deballasting the structure puts the bridge out of water. The assembly is then towed to its final installation site.

Sur les champs pétroliers de profondeur moyenne, de 40 à 120 m environ par exemple, tels qu'on en rencontre notamment en Mer du Nord, la mise en place de plates-formes semi-submersibles ou de navires du type "FPSO" s'avère particulièrement délicate du fait de la violence des charges d'environnement (vent, houle, courant, etc...), ce qui pénalise le dimensionnement des ancrages et par conséquent leur coût. Pour cette raison on préfère installer sur de tels sites des plates-formes fixes du type gravitaire.On medium depth oil fields, 40 to 120 m approximately for example, such as one meets some particularly in the North Sea, the establishment of platforms semi-submersible or "FPSO" type ships particularly delicate due to the violence of environmental loads (wind, swell, current, etc.), this which penalizes the dimensioning of anchors and by therefore their cost. For this reason we prefer install on such sites fixed platforms of the type gravity.

La présente invention a justement pour but de fournir un procédé d'installation d'une telle plate-forme gravitaire sur un champ pétrolier de profondeur moyenne, qui retient les avantages économiques évoqués ci-dessus du procédé d'installation d'une plate-forme semi-submersible "auto-élévatrice" sur un champ de grande profondeur décrit dans le brevet précité.The object of the present invention is precisely to provide a method of installing such a platform gravity on a medium depth oil field, which retains the economic advantages mentioned above of method of installing a semi-submersible platform "self-elevating" on a very deep field described in the aforementioned patent.

La présente invention a aussi pour but de fournir une plate-forme conçue pour la mise en oeuvre de ce procédé, ladite plate-forme comprenant en particulier, avantageusement, des moyens de stockage pour les produits extraits du champ pétrolier.The present invention also aims to provide a platform designed for the implementation of this process, said platform comprising in particular, advantageously, storage means for products extracted from the field oil.

On atteint ces buts de l'invention, ainsi que d'autres qui apparaítront à la lecture de la description qui va suivre, avec un procédé d'installation d'une plate-forme gravitaire auto-élévatrice du type décrit en préambule de la présente description, remarquable en ce que a) on remorque un ensemble flottant constitué par la sous-structure et le pont flottable reposant sur l'embase de ladite sous-structure, jusqu'à un site abrité intermédiaire de profondeur supérieure à celle du site d'installation final, b) on ballaste la sous-structure pour faire descendre celle-ci vers le fond alors que le pont flotte à la surface de l'eau, c) on arrête le ballastage de la sous-structure quand l'embase atteint une profondeur prédéterminée et on bloque alors le pont sur les colonnes de ladite embase, d) on déballaste ladite sous-structure jusqu'à ce que le pont soit remonté à une hauteur prédéterminée au-dessus de la surface de l'eau, e) on remorque l'ensemble jusqu'au site d'installation final et, f) on ballaste de nouveau la sous-structure jusqu'à ce qu'elle repose sur le fond marin.These objects of the invention are achieved, as well as others which will appear on reading the description which will follow, with a process for installing a platform self-elevating gravity of the type described in preamble to this description, remarkable in that a) a floating assembly consisting of the substructure is towed and the floating bridge resting on the base of said substructure, to an intermediate sheltered site deeper than the installation site final, b) we ballast the substructure to make descend this towards the bottom while the bridge floats at the surface of the water, c) the ballasting of the substructure is stopped when the base reaches a depth predetermined and then we block the bridge on the columns of said base, d) deballasting said substructure until the bridge is raised to a height predetermined above the water surface, e) on tows the assembly to the final installation site and, f) the substructure is ballasted again until that it rests on the seabed.

A l'étape c), la profondeur prédéterminée atteinte par l'embase est voisine de la somme de son tirant d'air sur le site d'installation final et de la profondeur du fond marin sur ce site.In step c), the predetermined depth reached by the base is close to the sum of its air draft on the final installation site and the depth of the seabed on this site.

D'autres caractéristiques et avantages de la présente invention apparaítront à la lecture de la description qui va suivre, et à l'examen du dessin annexé dans lequel :

  • les figures 1 et 2 sont des vues en élévation et en plan respectivement, d'un premier mode de réalisation d'une plate-forme conçue pour la mise en oeuvre du procédé suivant l'invention, la vue en plan ne faisant pas apparaítre les équipements portés par le pont de la plate-forme, pour la clarté du dessin,
  • la figure 3 est une vue en élévation d'une variante de la plate-forme des figures 1 et 2, et
  • les figures 4A à 4H illustrent le procédé d'installation suivant l'invention, des plates-formes des figures 1 à 3.
Other characteristics and advantages of the present invention will appear on reading the description which follows, and on examining the appended drawing in which:
  • Figures 1 and 2 are views in elevation and in plan respectively, of a first embodiment of a platform designed for the implementation of the method according to the invention, the plan view does not show the equipment carried by the deck of the platform, for the clarity of the drawing,
  • FIG. 3 is an elevation view of a variant of the platform of FIGS. 1 and 2, and
  • FIGS. 4A to 4H illustrate the installation method according to the invention, of the platforms of FIGS. 1 to 3.

On se réfère aux figures 1 et 2 du dessin annexé où il apparaít que la plate-forme représentée comprend essentiellement une sous-structure 1 et un pont 2. La sous-structure 1 comprend une embase 3 de plan rectangulaire et au moins deux, et dans l'exemple représenté quatre, colonnes 4i (i de 1 à 4) débordant vers le haut de l'embase 3, le pont 2 étant fixé à l'extrémité haute de ces colonnes comme représenté à la figure 1.Referring to Figures 1 and 2 of the accompanying drawing where it appears that the platform shown essentially comprises a substructure 1 and a bridge 2. The substructure 1 comprises a base 3 of rectangular plane and at least two, and in the example shown four, columns 4 i (i from 1 to 4) projecting upwards from the base 3, the bridge 2 being fixed to the upper end of these columns as shown in FIG. 1.

La sous-structure 1 représentée est donnée seulement à titre d'exemple illustratif et non limitatif. C'est ainsi que son embase pourrait aussi bien présenter une forme carrée, triangulaire, circulaire ou autre.The substructure 1 represented is given only by way of illustrative and nonlimiting example. This is how that its base could just as well have a shape square, triangular, circular or other.

L'embase est destinée à reposer sur le fond marin 9. Elle prend la forme d'un caisson parallélépipédique comportant avantageusement des compartiments de stockage de produits extraits du champ pétrolier et des compartiments de ballastage/déballastage. Ces derniers sont utilisés pendant l'installation de la plate-forme, comme on le verra plus loin. L'embase forme en phase d'exploitation une fondation de la plate-forme en assurant la stabilité de celle-ci par le simple effet poids comme il est connu dans l'art.The base is intended to rest on the seabed 9. It takes the form of a parallelepipedic box advantageously comprising storage compartments for products extracted from the oil field and compartments ballasting / deballasting. These are used during the installation of the platform, as we will see further. The base forms in operation a foundation of the platform ensuring the stability of this one by the simple effect weight as it is known in art.

Les colonnes 4i peuvent être réalisées dans le même matériau que l'embase ou dans un matériau différent. Elles ont pour fonction de supporter le pont. Elles délimitent aussi des compartiments de flottaison et peuvent accueillir différents matériels dits "utilités", tels que tuyauteries, pompes, réservoirs de fluides divers, etc...Columns 4 i can be made from the same material as the base or from a different material. Their function is to support the bridge. They also delimit flotation compartments and can accommodate various so-called "utility" materials, such as pipes, pumps, various fluid reservoirs, etc.

Les colonnes représentées à titre d'exemple ont une forme parallélépipédique. Elles pourraient aussi être de forme tronconique ou cylindrique par exemple. Elles présentent chacune une face verticale qui fait face au pont 2 comme représenté sur la figure 2 où il apparaít qu'une base rectangulaire 5 du pont 2 tangente les quatre colonnes 4i, à l'intérieur d'un espace délimité par celles-ci. Cette disposition permet le guidage latéral du pont par ces colonnes, pendant le ballastage de la sous-structure, comme on le verra plus loin.The columns shown by way of example have a parallelepiped shape. They could also be of frustoconical or cylindrical shape for example. They each have a vertical face which faces the bridge 2 as shown in Figure 2 where it appears that a rectangular base 5 of the bridge 2 tangent to the four columns 4 i , inside a space delimited by them . This arrangement allows lateral guidance of the bridge by these columns, during the ballasting of the substructure, as will be seen below.

Le pont présente de préférence une structure métallique dont la base 5 prend la forme d'un caisson, ou coque, assurant la flottabilité du pont, d'où le nom de pont-coque donné à ce type de pont. Il porte les équipements classiques : derrick 6, grue 7, quartiers d'habitation 8, etc... nécessaires à l'exécution des forages de puits sous-marins, puis à la remontée des produits extraits des puits.The bridge preferably has a structure metallic whose base 5 takes the form of a box, or hull, ensuring the buoyancy of the deck, hence the name deck-hull given to this type of deck. He wears classic equipment: derrick 6, crane 7, quarters 8, etc ... necessary for the execution of drilling of underwater wells, then upwelling products extracted from wells.

Le pont 2 est mobile verticalement par rapport aux colonnes 4i de la sous-structure 1, tout comme celui de la plate-forme auto-élévatrice décrite dans le brevet précité, et comporte donc des moyens de guidage latéral aux interfaces entre la base 5 du pont et les colonnes 4i et des moyens de verrouillage du pont sur les colonnes. On pourra se référer au brevet précité pour plus de détails concernant ces moyens de guidage et de verrouillage. Pour les besoins de la présente description on a représenté très schématiquement sur la figure 1 des moyens de verrouillage 101, 102, les deux autres colonnes recevant des moyens de verrouillage identiques.The bridge 2 is movable vertically with respect to the columns 4 i of the substructure 1, just like that of the jack-up platform described in the aforementioned patent, and therefore comprises means for lateral guidance at the interfaces between the base 5 of the bridge and the columns 4 i and of the means for locking the bridge on the columns. Reference may be made to the aforementioned patent for more details concerning these guiding and locking means. For the purposes of this description, there is shown very diagrammatically in FIG. 1 locking means 10 1 , 10 2 , the two other columns receiving identical locking means.

On se réfère maintenant aux figures 4A à 4H pour décrire le procédé d'installation suivant l'invention de la plate-forme des figures 1 et 2.We now refer to FIGS. 4A to 4H for describe the installation process according to the invention of the platform of Figures 1 and 2.

A la figure 4A, la sous-structure 1 est représentée à la fin de sa construction dans une cale sèche 11, d'un tirant d'eau de l'ordre d'une quinzaine de mètres par exemple. La figure 4B illustre la mise en eau de cette cale sèche, la sous-structure 1 étant alors mise en flottaison. Un remorqueur 12 vient tirer la sous-structure 1 hors de la cale 11 jusqu'à un site (figure 4C) où l'on procède à la mise en place du pont 2 sur l'embase 3 de la sous-structure 1. Le pont 2, flottant sur sa coque 5 , est engagé entre les colonnes 4i de la sous-structure 1, convenablement ballastée pour permettre à la coque 5 de passer au-dessus de la face supérieure de l'embase 3 de cette sous-structure.In FIG. 4A, the substructure 1 is shown at the end of its construction in a dry dock 11, with a draft of the order of about fifteen meters for example. FIG. 4B illustrates the impoundment of this dry dock, the substructure 1 then being placed in floatation. A tugboat 12 pulls the substructure 1 out of the hold 11 to a site (FIG. 4C) where the deck 2 is placed on the base 3 of the substructure 1. The deck 2, floating on its hull 5, is engaged between the columns 4 i of the substructure 1, suitably ballasted to allow the hull 5 to pass over the upper face of the base 3 of this substructure .

Alternativement, suivant le mode de réalisation décrit dans le brevet précité, et si les dimensions de la structure le permettent, on peut installer le pont-coque sur l'embase dans la cale sèche, la sous-structure étant ballastée et reposant sur le fond de la cale.Alternatively, depending on the embodiment described in the aforementioned patent, and if the dimensions of the structure allow, we can install the hull deck on the base in the dry dock, the substructure being ballasted and resting on the bottom of the hold.

L'embase 3 est ensuite déballastée (figure 4D) de manière que le pont-coque repose sur l'embase et que l'ensemble sous-structure/pont-coque puisse être remorqué jusqu'à un site abrité intermédiaire (figure 4E) dont, suivant l'invention, le fond marin est de profondeur supérieure à celle du fond du site final d'installation de la plate-forme, pour une raison qui apparaítra dans la suite.The base 3 is then deballasted (FIG. 4D) from so that the hull deck rests on the base and the sub-structure / deck-hull assembly can be towed to an intermediate sheltered site (Figure 4E) of which, according to the invention, the seabed is deep higher than the bottom of the final installation site of the platform, for a reason that will appear in the after.

Une fois arrivé sur ce site abrité, le ballastage de l'embase 3 est repris, assurant la descente de la sous-structure 1 et la mise en flottaison du pont-coque 2. Pendant cette descente, la stabilité hydrostatique de l'ensemble est assurée par la flottaison du pont-coque 2 à la surface de l'eau, la sous-structure 1 seule pouvant ne pas être stable dans toutes les phases d'immersion. Les colonnes 4i guident latéralement le pont-coque 2 pendant cette descente, comme décrit dans le brevet précité.Once on this sheltered site, the ballasting of the base 3 is resumed, ensuring the descent of the substructure 1 and the floating hull deck 2. During this descent, the hydrostatic stability of the assembly is ensured by the buoyancy of the hull deck 2 on the water surface, the substructure 1 alone may not be stable in all the immersion phases. The columns 4 i laterally guide the hull deck 2 during this descent, as described in the aforementioned patent.

Quand les surfaces supérieures des colonnes 4i arrivent au niveau de celle de la coque du pont 2, le ballastage de l'embase 3 est arrêté (figure 4F) celle-ci étant alors arrivée à une profondeur prédéterminée sensiblement égale à la somme de la profondeur du fond marin du site final d'installation de la plate-forme (40 mètres environ par exemple) et du tirant d'air du pont-coque au-dessus de l'eau, sur ce même site final (20 mètres environ par exemple). C'est pourquoi la profondeur du fond du site intermédiaire de déploiement de la plate-forme, d'au moins 60 mètres dans l'exemple donné, doit être supérieure à la profondeur du site final d'installation de la plate-forme.When the upper surfaces of the columns 4 i arrive at that of the hull of the deck 2, the ballasting of the base 3 is stopped (FIG. 4F), the latter then having reached a predetermined depth substantially equal to the sum of the depth of the seabed of the final installation site of the platform (approximately 40 meters for example) and of the draft of the hull deck above the water, on this same final site (approximately 20 meters by example). This is why the depth of the bottom of the intermediate platform deployment site, at least 60 meters in the example given, must be greater than the depth of the final platform installation site.

Les moyens de verrouillage 10i sont alors actionnés pour empêcher tout nouveau déplacement relatif de la sous-structure 1 par rapport au pont-coque 2 (figure 4F).The locking means 10 i are then actuated to prevent any further relative movement of the substructure 1 relative to the hull deck 2 (FIG. 4F).

La sous-structure est ensuite déballastée pour faire remonter la face inférieure de l'embase 3 à une profondeur inférieure à celle du site final d'installation (figure 4G) de manière à permettre le remorquage de la plate-forme jusqu'à ce site. Une fois celui-ci atteint (figure 4H) on ballaste de nouveau la sous-structure jusqu'à ce que celle-ci vienne reposer sur le fond marin 9, de manière à assurer la stabilité de la plate-forme sur ce fond. Dans cette position, le pont 2 émerge au-dessus de l'eau avec le tirant d'air convenable, réglé comme expliqué ci-dessus en liaison avec la figure 4F.The substructure is then deballasted to make raise the underside of the base 3 to a depth lower than that of the final installation site (Figure 4G) so as to allow towing of the platform to this site. Once this is reached (Figure 4H) we ballast again the substructure until this one come to rest on the seabed 9, so as to ensure the stability of the platform on this background. In this position, deck 2 emerges over the water with the suitable air draft, set as explained above in link with FIG. 4F.

En variante, la plate-forme pourrait prendre la forme de celle représentée à la figure 3 qui ne diffère de celle des figures 1 et 2 qu'en ce que le pont ne comporte pas de coque et n'est donc pas indépendamment flottable. L'installation de cette plate-forme se déroule sensiblement comme décrit en liaison avec les figures 4A à 4H, à ceci près que la figure 4C' doit être substituée à la figure 4C. Sur la figure 4C' il apparaít que le pont 2 arrive chargé sur une barge 13 qui va jouer le rôle de la coque du pont de la plate-forme des figures 1 et 2, jusqu'à l'étape 4F où la barge est dégagée de la plate-forme après le verrouillage du pont. Alternatively, the platform could take the form from that shown in Figure 3 which does not differ from that Figures 1 and 2 that in that the bridge does not include hull and is therefore not independently buoyant. The installation of this platform takes place substantially as described in connection with Figures 4A to 4H, at this except that Figure 4C 'should be substituted for Figure 4C. In Figure 4C 'it appears that the deck 2 arrives loaded on a barge 13 which will play the role of the hull of the bridge from the platform of Figures 1 and 2, up to step 4F where the barge is cleared from the platform after the bridge lock.

Il apparaít maintenant que la présente invention permet bien d'atteindre les buts fixés, à savoir réaliser une plate-forme gravitaire conçue pour être installée en eau peu profonde et retenant les avantages économiques des plates-formes auto-élévatrices pour lesquelles l'installation sur site est obtenue par le seul jeu de la gravité et de la poussée d'Archimède exercées sur ses constituants, sans recours à des mécanismes élévateurs coûteux. En outre il est possible de stocker les produits extraits du champ pétrolier sur la plate-forme elle-même, grâce aux compartiments prévus à cet effet dans son embase.It now appears that the present invention achieves the goals set, namely to achieve a gravity platform designed to be installed in shallow water and retaining the economic benefits of self-elevating platforms for which on-site installation is achieved by the only game of the gravity and the buoyancy exerted on its constituents, without the use of lifting mechanisms expensive. In addition it is possible to store the products extracts from the oil field on the platform itself, thanks to the compartments provided for this purpose in its base.

L'installation du pont complètement équipé sur la structure permet par ailleurs de faire l'économie des lourds et coûteux moyens de levage qui sont nécessaires dans le cas d'installation du pont et des équipements en mer après la pose de la sous-structure sur son site final d'exploitation.The installation of the fully equipped bridge on the structure also saves money heavy and expensive lifting means that are required in the case of installation of the bridge and the equipment in sea after the installation of the substructure on its final site operating.

Claims (1)

  1. A method of installing a self-elevating gravity platform for offshore oil field operation, said platform including a selectively buoyant sub-structure (1) comprising a base (3) and at least two columns (4i) upstanding from said base, and a selectively buoyant deck-hull (2) mounted on said columns (4i),
       said gravity platform being self-elevating in that deck (2) is vertically movable with respect to columns (4i) of the sub-structure (1), said method being characterised in that:
    a) the complete floating combination of the sub-structure (1) and the selectively buoyant deck (2) resting on the base (3) of said sub-structure (1) is towed to an intermediate sheltered site where the water is deeper than at the final installation site of the platform,
    b) the sub-structure (1) is ballasted so that it descends towards the sea floor and the deck (2) floats on the surface of the water,
    c) ballasting of the sub-structure (1) is stopped when the base (3) reaches a predetermined depth at which point the deck (2) is fixed to the columns (4i) of the base (3),
    d) said sub-structure (1) is deballasted until the deck has risen a predetermined height above the surface of the water,
    e) the combination is towed to the final installation site, and
    f) the sub-structure (1) is ballasted again until it rests on the sea floor.
EP19990401357 1998-06-08 1999-06-04 Method for the installation of a gravity, self-elevating oil production platform at sea Expired - Lifetime EP0963906B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9807176 1998-06-08
FR9807176A FR2779408B1 (en) 1998-06-08 1998-06-08 METHOD OF INSTALLING A SELF-LIFTING GRAVITY PLATFORM FOR THE OPERATION OF AN OIL FIELD AT SEA

Publications (2)

Publication Number Publication Date
EP0963906A1 EP0963906A1 (en) 1999-12-15
EP0963906B1 true EP0963906B1 (en) 2002-04-03

Family

ID=9527129

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19990401357 Expired - Lifetime EP0963906B1 (en) 1998-06-08 1999-06-04 Method for the installation of a gravity, self-elevating oil production platform at sea

Country Status (2)

Country Link
EP (1) EP0963906B1 (en)
FR (1) FR2779408B1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL2006667C2 (en) * 2011-04-26 2012-10-29 Ihc Holland Ie Bv Vessel comprising a moon pool and a hoisting arrangement and method of lowering items into the sea.
RU2512783C1 (en) * 2012-10-09 2014-04-10 Федеральное государственное унитарное предприятие "Крыловский государственный научный центр" Sea gravity platform
CN106836164B (en) * 2016-12-15 2019-11-08 大连船舶重工集团有限公司 A kind of rotary Multidirectional-moving cantilever beam

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NO141859C (en) * 1973-10-12 1980-05-21 Doris Dev Richesse Sous Marine FRACTION PLATFORM OF THE Gravity type for installation at Sjöes.
GB1523585A (en) * 1975-10-28 1978-09-06 Brewerton R W Offshore platforms
NO151209C (en) * 1976-05-20 1985-02-27 Doris Dev Richesse Sous Marine FOREIGN BUILDINGS AND PROCEDURE FOR ITS MANUFACTURING
FR2400086A1 (en) * 1977-08-08 1979-03-09 Sea Tank Co Mounting of maritime platform on hollow base with legs - includes submerging base using winches for elevating once platform is floated over
US5609442A (en) * 1995-08-10 1997-03-11 Deep Oil Technology, Inc. Offshore apparatus and method for oil operations
FR2772336B1 (en) 1997-12-12 2000-01-14 Doris Engineering SEMI-SUBMERSIBLE PLATFORM FOR OPERATING AN OIL FIELD AT SEA AND METHOD FOR INSTALLING SUCH A PLATFORM

Also Published As

Publication number Publication date
FR2779408B1 (en) 2000-07-21
FR2779408A1 (en) 1999-12-10
EP0963906A1 (en) 1999-12-15

Similar Documents

Publication Publication Date Title
EP2441893B1 (en) Support device for a wind turbine for producing electric power at sea, corresponding facility for producing electric power at sea.
EP0979923B1 (en) Installation for the exploitation of an offshore oil deposit and method for mounting a riser
FR3051823A1 (en)
FR2559808A1 (en) COMPOSITE PLATFORM FOR OIL OPERATIONS IN POLAR SEAS
FR2772336A1 (en) SEMI-SUBMERSIBLE PLATFORM FOR OPERATING AN OIL FIELD AT SEA AND METHOD FOR INSTALLING SUCH A PLATFORM
EP0307255B1 (en) Catenary anchor line for a floating device, and apparatus and method for operating this anchor line
FR2631355A1 (en) PROTECTION DEVICE FOR SEA WORKS AND METHOD FOR IMPLEMENTING SAID DEVICE
EP1348867B1 (en) Offshore wind-power plant as well as construction and erection method for such a plant
EP3635180B1 (en) Launching method
EP3286069B1 (en) Floating mounting having a depth-variable horizontal cross-section
FR2499935A1 (en) STRUCTURE OF DRILLING AND PRODUCTION AT SEA
EP0963906B1 (en) Method for the installation of a gravity, self-elevating oil production platform at sea
EP0959182B1 (en) Self-rising offshore platform and installation process of same
FR2970748A1 (en) Method for realizing maintenance operations i.e. replacement of heavier parts, of floating wind turbine device of off-shore wind energy production system, involves positioning floating wind turbine device on maintenance device
EP3490882A1 (en) Floating support structure comprising a floater and a damping plate with a row of apertures
FR2525176A1 (en) HALF-IMMEREDE SEA DRILLING STRUCTURE
EP1204806B1 (en) Floating support comprising a central cavity including a plurality of sections
FR2713588A1 (en) Self-elevating floating platform
CA2311256C (en) Wellhead platform for the operation of arctic oil fields
KR101370525B1 (en) Gravity Based Offshore Structure Using Neutral Buoyancy and Construction Method of the Same
FR2581362A1 (en) Semi-submersible platform, in particular for exploration and/or working underwater deposits in cold seas
WO2021094191A1 (en) Installation for supporting a self-raising platform
WO2018189084A1 (en) Floater, in particular for an offshore wind turbine
JP7495802B2 (en) Construction method of floating water structure and temporary mooring float used therefor
FR2720086A1 (en) Procedure for installation of device for protection against swell

Legal Events

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

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DK FR GB IE NL

AX Request for extension of the european patent

Free format text: AL;LT;LV;MK;RO;SI

17P Request for examination filed

Effective date: 20000214

AKX Designation fees paid

Free format text: DK FR GB IE NL

REG Reference to a national code

Ref country code: DE

Ref legal event code: 8566

17Q First examination report despatched

Effective date: 20010409

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DK FR GB IE NL

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

Ref country code: GB

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20020403

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

Free format text: FRENCH

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

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20020703

GBV Gb: ep patent (uk) treated as always having been void in accordance with gb section 77(7)/1977 [no translation filed]

Effective date: 20020403

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

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

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

26N No opposition filed

Effective date: 20030106

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

REG Reference to a national code

Ref country code: FR

Ref legal event code: RN

Ref country code: FR

Ref legal event code: FC

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 17

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

Ref country code: NL

Payment date: 20150521

Year of fee payment: 17

Ref country code: IE

Payment date: 20150519

Year of fee payment: 17

Ref country code: FR

Payment date: 20150416

Year of fee payment: 17

REG Reference to a national code

Ref country code: NL

Ref legal event code: MM

Effective date: 20160701

REG Reference to a national code

Ref country code: IE

Ref legal event code: MM4A

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20170228

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

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20160630

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

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20160604

Ref country code: NL

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20160701