EP2646725B1 - Marine mounting provided with a device for storing and guiding hoses - Google Patents

Description

The present invention relates to a support installed at sea open, fixed or floating, that is to say resting or respectively anchored at the bottom of the sea, said support being equipped on the surface with a storage device and guide flexible pipes capable of storing and guiding a plurality, preferably at least 3 said flexible pipes useful for the offshore transfer of petroleum products.

The device for storing and guiding flexible pipes disposed on board a support according to the invention allows the handling of said flexible pipes for their storage in the wound state between two fluid transfers within said flexible pipes between the floating support and a removal vessel, and for the conduct of said pipes in order to implement a said transfer of fluid between a said floating support and a said vessel preferably of the LNG type.

A particular technical field of use of a support according to the invention is the field of offshore discharge of petroleum products including both liquid crude oil and diesel or liquefied gases, in particular natural gas LNG, or gas in the gaseous state, from a said support, for example at a petroleum field, to a removal vessel disposed in pairs or in tandem as explained below.

The technical field of the invention is more particularly the field of the transfer at sea of liquefied natural gas (LNG) at -165 ° C, between a floating support comprising at least one LNG storage tank, and a vessel preferably of LNG type arranged in tandem or in pairs, that is to say at a distance from the floating support in the same longitudinal direction as said floating support, or parallel thereto.

On offshore oilfields, located a great distance from the coast, petroleum products such as oil or gas are general recovered, processed and stored aboard a said floating support including the type called FPSO ("Floating-Production-Storage-Offloading"), ie floating support production, storage and unloading. Petroleum products such as oil and / or gas are then exported by removing vessels that come regularly, for example every week, to recover the production of the field. Three techniques are commonly used for this purpose.

A first technique consists in installing, at a distance of about 1000-1500m from the FPSO, a so-called loading buoy connected to the FPSO by an underwater pipe, the oil or gas being transferred into said unloading buoy via said sub-pipe. Marine. An abducting tanker then berths at said loading buoy, then the load is recovered via flexible connecting pipes connected to said buoy floating on the surface of the sea, the oil or gas being then pushed by a pump on board. FPSO to perform the loading of the oil tanker.

A second technique is to bring the removal vessel FPSO couple, that is to say bordered against the plating. In this case, the transfer is carried out either by articulated type loading arms, as is usual during transfers to the port, or by flexible pipes of reduced lengths.

A third technique consists in arranging the collecting vessel in tandem with the FPSO, that is to say that the collecting vessel is positioned in the axis of the FPSO at a safety distance of at least 50 to 150 m, then mooring at the latter, and recovering the end of the flexible pipes extending from the floating support where they are connected to a tank at their other end and floating on the sea, to connect them on board the said removing vessel, the oil or the gas is then pushed by a pump from the FPSO to perform the loading of the oil tanker.

On the oilfields, it is generally preferred to implement a loading buoy, but it is generally associated with a redundancy device that can be either a torque device that is to say with a removal vessel arranged at FPSO torque, ie a tandem device that is to say with a removal vessel arranged in tandem of the FPSO, sometimes even both devices.

In the case of crude oil, in all configurations, the connecting lines, either to an unloading buoy or to a removing vessel, remain full, either of said crude oil or of a petroleum product, generally diesel, used to replace crude oil when the latter presents risks of freezing (paraffinic crudes).

On the other hand, when it is a question of transfer of liquefied gas of the LNG type at -165 ° C, the transfer devices comprise at least one forward link line for the liquefied gas, and a return link line, in general of smaller diameter, to evacuate the gas from the vessels of the removal vessel as and when filled by LNG, especially methane gas, so reliquefier aboard the FPSO. In addition, the flexible connection lines must be almost completely emptied after unloading, so as to prevent the formation and accumulation of ice on said pipes and more particularly at the mechanical connections of said pipes. In addition, the latter must be extremely insulated in order to limit the regasification of liquid methane (LNG) during its transfer. This is why, for this purpose, unloading methods are preferred with torque and tandem devices in which the connecting lines are not submarine pipes but pipes floating on the surface, on the one hand, and on the other hand. on the other hand, said pipes being relatively shorter in length.

The unloading torque is however very delicate because the approach of a removing vessel to come to position parallel to the FPSO within 5m of distance, is possible only in very lenient sea conditions. Indeed, in case of bad seas, the transfer becomes impossible and this may lead, if the FPSO is full, to have to stop production, which is a serious handicap for the profitability of the operating facilities of the oil field in question. In this case, the transfer means consist of loading arms conventional devices, or devices with flexible pipes, installed on board said FPSO. The patent EP-2,239,190 describes such a device for unloading torque.

Tandem unloading is much safer, but the unloading lines are longer and therefore more complicated to maneuver and store onboard the FPSO. To this end, numerous devices for storing and guiding flexible pipes onboard the FPSO have been developed. Some use a considerable articulated type supporting structure supporting a plurality of rigid pipes having rotary joints as a hinge, as detailed in the patent. US 4393906

Other solutions include the use of articulated rigid pipes with rotating joints, or hoses arranged in a daisy chain between the FPSO and the removing vessel, as explained in the patent. WO / 01-04041 .

Another technical area is the offshore storage of LNG near a site of use, for example to ship the gas on the continent after regasification, or to transform it on the spot into electrical energy to send back the electricity in the local network. In this case, the ship unloads its cargo of LNG and the floating support is called "FSRU" (Floating Storage Regase Unit), ie floating storage unit and regasification.

A known example is disclosed in the patent JP2009236286A .

The object of the present invention is to provide a device for unloading in torque or in tandem between a support and an improved removal vessel.

More particularly, the object of the present invention is to provide a support at sea equipped with a device for supporting and guiding flexible pipes facilitating the handling of said pipes to implement a transfer of fluid between the floating support and a removing vessel and for storing said flexible pipes on board the floating support between two transfers.

A problem to be solved according to the present invention is to provide a device for storing and guiding said flexible pipes which make it possible to regulate in a controlled manner the tension and the length between said floating support and said stripping vessel so as in particular to prevent the interfering a plurality of connecting lines extending between said floating support and said stripping vessel from the storage and guidance device.

• une première structure porteuse supportant une pluralité de plateaux tournants disposés les uns au dessus des autres,
• des conduites flexibles enroulées ou aptes à être enroulées en spirales juxtaposées concentriques de diamètres croissants reposant sur les faces supérieures desdits plateaux,
• un raccord à joint tournant permettant le raccordement entre d'une part une première extrémité la plus proche du centre du plateau d'une conduite flexible enroulée sur ledit plateau, apte à être entrainée en rotation avec ledit plateau, et d'autre part une extrémité d'une conduite de transfert qui reste fixe lorsque ledit plateau est entrainé en rotation, de préférence en communication avec au moins une première cuve au sein dudit support, et
• une pluralité de moyens de guidage, aptes à guider les portions de dites conduites flexibles à l'extérieur desdits plateaux tournants en continuité des portions restantes de conduites reposant sur lesdits plateaux, de telle sorte que lesdites portions de conduites en sortie desdits plateaux soient disposées rectilignement, à des positions différentes dans une direction Y₁Y'₁ horizontale parallèle au dit bordé, à des hauteurs différentes et pouvant adopter des inclinaisons différentes α1, α2, α3 de leurs plans axiaux verticaux P1, P2, P3 par rapport à ladite direction Y₁Y₁' horizontale parallèle au dit bordé.

To do this, the present invention essentially consists of a support installed at sea equipped with a device for storing and guiding flexible pipes, comprising:

• a first supporting structure supporting a plurality of rotating plates arranged one above the other,
• flexible pipes wound or capable of being wound in concentric juxtaposed spirals of increasing diameter resting on the upper faces of said plates,
• a rotary joint connection allowing the connection between firstly a first end closest to the center of the plate of a flexible pipe wound on said plate, adapted to be rotated with said plate, and secondly an end a transfer line which remains fixed when said plate is rotated, preferably in communication with at least a first tank within said support, and
• a plurality of guide means, able to guide the portions of said flexible pipes outside said rotating plates in continuity with the remaining portions of pipes resting on said plates, so that said portions of pipes at the outlet of said plates are arranged rectilinearly at different positions in a direction Y ₁ Y ' ₁ horizontal parallel to said plating, at different heights and able to adopt different inclinations α1, α2, α3 of their vertical axial planes P1, P2, P3 with respect to said direction Y ₁ Y ₁ 'horizontal parallel to said plating.

• une première structure porteuse reposant sur ou solidaire du pont dudit support à proximité d'un bordé dudit support, de préférence une paroi d'une extrémité longitudinale dudit support, ladite première structure porteuse supportant une pluralité de plateaux circulaires tournants disposés les uns au dessus des autres,
• chaque dit plateau tournant étant apte à être entrainé en rotation de façon motorisée par un premier moteur selon un axe central vertical ZZ' indépendamment les uns des autres, de préférence selon un même axe central vertical ZZ', chaque plateau tournant comportant un orifice central surmonté par un fût central contre et autour duquel une dite conduite flexible peut être enroulée en spirales juxtaposées concentriques de diamètres croissants reposant sur la face supérieure dudit plateau, ledit orifice central dudit plateau tournant étant équipé d'un raccord à joint tournant apte à permettre le raccordement entre d'une part une première extrémité la plus proche dudit fût central d'une conduite flexible enroulée autour dudit fût central, la dite première extrémité de conduite étant apte à être entrainée en rotation avec ledit plateau tournant, et d'autre part une extrémité d'une conduite de transfert fixe dont l'autre extrémité est en communication avec au moins une première cuve au sein dudit support, et
• une pluralité de moyens de guidage, chaque dit moyen de guidage étant apte à guider la portion de dite conduite en sortie de respectivement chaque dit plateau tournant en continuité de la portion de conduite enroulée sur ledit plateau, de telle sorte que les différentes dites portions de conduites en sortie des différents plateaux tournants soient disposées rectilignement, décalées à des positions différentes dans une direction Y1Y'1 horizontale parallèle au dit bordé, à des hauteurs différentes et pouvant adopter une inclinaison de leurs plans axiaux verticaux différentes par rapport à ladite direction Y₁Y₁' horizontale parallèle au dit bordé.

More precisely, the present invention provides a support installed at sea, in a fixed or floating manner, said support being equipped on the surface with a device for storing and guiding flexible pipes capable of storing and guiding a plurality, preferably at least 3 said flexible pipes, characterized in that said storage and guiding device comprises:

• a first support structure resting on or integral with the bridge of said support near an edge of said support, preferably a wall of a longitudinal end of said support, said first support structure supporting a plurality of rotating circular plates arranged above one of other,
• each said turntable being adapted to be driven in rotation mechanically by a first motor along a vertical central axis ZZ 'independently of one another, preferably along the same vertical central axis ZZ', each turntable having a central orifice surmounted by a central shaft against and around which a said flexible pipe can be wound in concentric juxtaposed spirals of increasing diameters resting on the upper face of said plate, said central orifice of said turntable being equipped with a rotary joint connection adapted to allow the connection between on the one hand a first end closest to said central shaft of a flexible pipe wound around said central shaft, said first pipe end being adapted to be rotated with said turntable, and secondly one end a fixed transfer line whose other end is in communication with with at least a first tank within said support, and
• a plurality of guide means, each said guide means being adapted to guide the portion of said pipe output respectively of said said turntable in continuity with the pipe portion wound on said plate, so that the different said portions of the output ducts of the different rotating plates are arranged rectilinearly, shifted at different positions in a horizontal direction Y1Y'1 horizontal parallel to said plating, at different heights and able to adopt an inclination of their vertical vertical planes different from said direction Y ₁ Y ₁ 'horizontal parallel to said plating.

It will be understood that the pipe portion at the outlet of the plate corresponds to the non-wound pipe portion in continuity with the last turn of the wound pipe, in particular during winding or unwinding.

The device according to the invention is particularly advantageous for arranging relative to each other and for independently adjusting the length and / or the voltage of the different pipes extending at the outlet of trays between said plates and the second ends of flexible pipes opening in particular to a second vessel, in particular an eradicating vessel, so that they do not risk interfering with each other, or even colliding with each other, especially during unwinding or winding of the pipe before or after deployment of said pipes between said floating support and said removing vessel.

This independent adjustment of the rotation of the various rotating plates is particularly useful and advantageous when the various flexible pipes wound on the various rotating plates are of different diameters and therefore requires a different winding or unwinding speed to maintain a length or a voltage substantially identical output of said turntables during their winding and unwinding.

This is particularly the case when LNG-type liquefied gas is transferred from a floating support according to the invention to a removal vessel while in another flexible pipe, generally of smaller diameter, gas is transferred to the vessel. gaseous state corresponding to the gas sky tanks from said removing vessel to said floating support back as explained below.

By "bordered" is meant here any external wall of the hull of the ship, namely the lateral longitudinal walls of the ship. shell that the transverse walls at the longitudinal ends, namely the front and rear walls of said support.

Here, the term "flexible pipe" refers to the pipes known under the name "flexible", which are well known to those skilled in the art and which have been described in the normative documents published by the American Petroleum Institute (API), more particularly under the API 17J and API RP 17 B references. Such hoses are in particular manufactured and marketed by COFLEXIP France. These flexible pipes generally comprise internal sealing layers of thermoplastic materials associated with layers resistant to the pressure internal to the pipe, generally made of steel or composite materials made in the form of spiral strips, contiguous inside the thermoplastic pipe to withstand the internal burst pressure and supplemented by external reinforcements above the thermoplastic tubular layer also in the form of contiguous spiral strips, but with a longer pitch, that is to say an angle of inclination of the lower helix, in particular from 15 ° to 55 °.

More particularly, at least one said flexible pipe is wound against and around a said central shaft in concentric juxtaposed spirals of increasing diameter resting on said turntable, said central shaft having a radius greater than the minimum radius of curvature of said flexible pipe, preferably at least 3 flexible pipes are wound on respectively at least 3 said rotating plates, including at least one flexible pipe of smaller diameter than the others.

The assembly of said storage and guiding device, said flexible ducts being guided by means of a said storage and guiding device, and if necessary of said first and second connection device and valves, constitute a device fluid transfer from a said support installed at sea, preferably to a said vessel.

The present invention also provides a method for transferring a liquid or gaseous petroleum product in which a said petroleum product is transferred into at least two flexible pipes, preferably at least three flexible pipes extending between a said support according to the invention and a vessel preferably of the LNG type arranged in pairs or tandem next to said floating support opposite said plating, said flexible pipes being guided by means of a said storage and guiding device.

In a first embodiment, said transfer consists of an unloading of the liquefied gas from said support to a said vessel, called the removing vessel.

In a second embodiment, said transfer consists of a liquefied gas charge from a said ship, referred to as a supply vessel, to said support. In general, it is a loading of liquefied gas that is regasified within said support, to be transferred to land in gaseous form or for use in generating electricity. In this case, said floating support may also contain a unit for generating electricity from said gas and a transformer station for sending electrical power to the earth. In this case, said support is advantageously a support resting at the bottom of the sea.

Advantageously in a transfer process according to the invention, said flexible pipes are floating pipes, floating on the surface over a portion of the distance between said support and said vessel preferably of the LNG type.

More particularly still, in a transfer process according to the invention, at least one first flexible pipe, preferably at least two first and second flexible pipes, in which liquefied gas is transferred between said support, is used. and at least a second tank of said vessel preferably of LNG type, and a third flexible pipe, preferably of smaller diameter than said first and second flexible pipes in which gas corresponding to the gas sky of the second tank is transferred between a said second tank to a first tank within said floating support or a liquefaction unit on a said support before transfer to a said first tank.

In particular, in the case where said LNG tanker is a scavenger vessel and where the liquefied gas is discharged from said floating support to said scavenging vessel, the return of gas from said scavenger vessel to said floating support is as follows. and as the filling of said second tank within said removing vessel.

More particularly in a floating support according to the invention, each said guide means is disposed at a different height vis-à-vis each said turntable respectively, so as to be able to support a curved intermediate portion of pipe between a downstream portion of said pipe in a substantially vertical position along said plating and a said upstream portion of the pipe at the outlet of the plate in continuity with the wound pipe portion resting on a said turntable, said upstream portion of the pipe at the outlet of the plate; extending on a virtual plane P substantially tangent to the surface of the upper face of said plate on which said wound pipe portion is wound, the different downstream pipe portions in a substantially vertical position along said strip being disposed in offset position relative to each other; to others in a said direction Y ₂ Y ₂ 'parallel to the said bordered at the output of the said oulies.

More particularly still, each said guide means comprises a pulley of horizontal axis Y ₁ Y ₁ 'of first rotation on itself, said pulley being further able to move, preferably freely, in second rotation with respect to a vertical axis passing through a diameter of the pulley, said first rotation on itself of each said pulley being preferably controlled by a second motor, preferably synchronized with said first motor of each said plate.

Thus, because of said second free rotation of said pulley about its vertical axis Z ₁ Z ₁ 'and said first motorized synchronized rotation of said pulley about its horizontal axis Y ₁ Y ₁ ', said intermediate portion of supported curved line by said pulley can remain permanently in the same substantially vertical plane P1, P2, P3 that a said upstream portion of the pipe at the outlet of the plateau, the different planes P1, P2, P3 being inclined at a different angle α1, α2, α3 with respect to said direction Y ₁ Y ' ₁ , to arrive at said turntable in continuity and tangential alignment of the end of the last turn of wound pipe allowing the optimal trenching of the pipe as winding or unwinding of said pipe around said central shaft.

It is understood that it is the vertical axial plane P1, P2, P3 of said upstream and intermediate pipe portions which are located in a same substantially vertical plane and that in contrast the axial plane of the downstream pipe portion in position substantially vertical will not necessarily be located in this same vertical plane.

In an alternative embodiment of a floating support according to the invention, said guide means are constituted simply by chutes.

More particularly, the different pulleys are disposed offset from each other in said horizontal direction Y ₁ Y ' ₁ horizontal parallel to said plating, at different heights, the high point of each pulley preferably being positioned substantially at the level of a tangent plane P to the upper face of a said turntable.

It will be understood that the different downstream pipe portions in a substantially vertical position along said plating are thus arranged side by side in a said direction Y ₁ Y ₁ ', preferably parallel to the said ply at the outlet of the said pulleys, preferably each pulley being adjustable in height with respect to said portion of said second bearing structure attached to said plating.

More particularly, each pulley is supported by a second bearing structure disposed outside said floating support and fixed to the same plating at a different position in a said horizontal direction Y ₁ Y ₁ 'parallel to said ply, each pulley being hinged in said second rotation of vertical axis Z ₁ Z ₁ 'with respect to a part of its said second supporting structure fixed to said plating.

More particularly, each said plate comprises or cooperates in the underside with rollers adapted to cooperate with or respectively supported by elements of said carrier structure and each said turntable comprises at said central orifice a bearing integral with said first bearing structure adapted to allow the rotation of said plate in relative rotation with respect to said first bearing structure.

• au moins un dit plateau tournant présente une face supérieure plane horizontale ;
• au moins un dit plateau tournant présente une face supérieure de forme tronconique concave, de préférence d'angle au sommet γ de 160 à 178°;
• au moins un dit plateau tournant présente une face supérieure de forme tronconique convexe de préférence d'angle au sommet γ de 160 à 178.

According to different embodiments, said rotating plates may be such that:

• at least one said turntable has a flat horizontal top face;
• at least one said turntable has an upper face of concave frustoconical shape, preferably with an apex angle γ of 160 to 178 °;
• at least one said turntable has an upper face of convex frustoconical shape preferably with an apex angle γ of 160 to 178.

Concave or convex frustoconical shape is understood here to mean that the virtual vertex of said cone is below or respectively above said frustoconical surface. It is understood that the angle α of conicity relative to the horizontal will be 1 to 10 °.

• à une première extrémité à un premier élément de raccordement de conduite, de préférence une partie mâle ou femelle d'un connecteur automatique, et
• à sa deuxième extrémité un deuxième élément de raccordement, de préférence une bride, assemblée à la deuxième extrémité d'une dite conduite flexible, et
• chaque dite première portion de conduite comprenant entre ses deux extrémités (n-1) dérivations permettant la communication avec respectivement une des (n-1) autres dites premières portions de conduites rigides, chaque dite dérivation comprenant une première vanne de communication, et
• une première vanne de connexion située entre ledit premier élément de raccordement et ladite dérivation,
• lesdites premières portions de conduites étant de préférence maintenues parallèles par un premier support rigide auquel elles sont solidarisées,
• lesdites premières vannes de communication étant de préférence des vannes papillons et lesdites premières vannes de connexion étant de préférence des vannes à boisseau sphérique.

A convex or concave frustoconical turntable is particularly useful for purging the residual charge of a flexible pipe filled with liquid, in particular liquefied gas, stored and wound on its turntable, as explained hereinafter. the invention, it is equipped with a plurality of n flexible pipes each cooperating with a said turntable at their said first ends, said flexible pipes being joined together at their second ends by a first connection device and valves comprising n first portions of pipes, preferably rigid, maintained in fixed relative position relative to each other, preferably parallel, n being an integer at least equal to 3, each said first pipe portion comprising:

• at a first end to a first pipe connection member, preferably a male or female portion of an automatic connector, and
• at its second end a second connecting element, preferably a flange, assembled at the second end of a said flexible pipe, and
• each said first pipe portion comprising between its two ends (n-1) branches allowing the communication with respectively one of (n-1) other said first portions of rigid pipes, each said branch comprising a first communication valve, and
• a first connection valve located between said first connection element and said branch,
• said first pipe portions being preferably held parallel by a first rigid support to which they are secured,
• said first communication valves preferably being butterfly valves and said first connecting valves preferably being ball valves.

It will be understood that each said first connection valve situated between said first connection element and said branch is able to allow or prevent fluid circulation in said first pipe portion to or from said first connection element when it is open or respectively closed.

• n deuxièmes portions de conduites, de préférence rigides,
• chaque dite deuxième portion de conduite communicant à une de ses extrémités avec une dite deuxième cuve et comprenant à son autre extrémité un premier élément de raccordement complémentaire de conduite, ledit premier élément de raccordement complémentaire étant apte à coopérer en raccordement réversible avec un dit premier élément de raccordement, ledit premier élément de raccordement complémentaire étant de préférence une partie femelle ou respectivement mâle de connecteur automatique,
• lesdites deuxièmes portions de conduite étant maintenues en position relative fixe les unes par rapport aux autres de préférence parallèlement de façon à permettre le raccordement desdits premiers éléments de raccordement complémentaires avec lesdits premiers éléments de raccordements,
• chaque dite deuxième portion de conduite comprenant une deuxième vanne de connexion apte à autoriser ou empêcher la circulation de fluide dans ladite deuxième portion de conduite vers ou provenant dudit premier élément de raccordement complémentaire lorsqu'elle est ouverte ou respectivement fermée,
• lesdites deuxièmes portions de conduite étant de préférence maintenues parallèles entre elles par un deuxième support rigide auquel elles sont solidarisées,
• lesdites deuxièmes vannes de connexion étant de préférence des vannes à boisseau sphérique.

According to another preferred feature of the support according to the invention, said flexible pipes extend or are able to extend between said support and a vessel preferably of the LNG type arranged in pairs or tandem beside said support opposite said plating. , and said first connecting device and valves is connected to a second connecting device and valves disposed or adapted to be disposed on board said vessel preferably of LNG type, said second connecting device and valves comprising:

• n second portions of pipes, preferably rigid,
• each said second pipe portion communicating at one of its ends with a said second tank and comprising at its other end a first complementary pipe connection element, said first complementary connecting element being able to cooperate in reversible connection with a said first element connection, said first complementary connecting element being preferably a female or male part of automatic connector,
• said second pipe portions being held in fixed relative position with respect to each other preferably parallel so as to allow the connection of said first complementary connecting elements with said first connecting elements,
• each said second pipe portion comprising a second connecting valve adapted to allow or prevent the flow of fluid in said second pipe portion to or from said first complementary connecting element when it is open or respectively closed,
• said second pipe portions being preferably held parallel to each other by a second rigid support to which they are secured,
• said second connecting valves being preferably ball valves.

A support as defined above is particularly useful and advantageous for carrying out the almost complete purging of the flexible pipes before re-winding them on their turntable, this to avoid any damage to said flexible pipes on the one hand and the other part of facilitating this re-winding on their said turntable.

1. a. On ferme lesdites premières et deuxièmes vannes de connexion, et l'on déconnecte l'un de l'autre lesdits premier et deuxième dispositifs de connexion et de vannes, et
2. b. On injecte du gaz à la première extrémité d'une première conduite flexible depuis ledit support et on ouvre au moins une dite première vanne de communication entre ladite première conduite flexible et une deuxième conduite flexible assemblée au même dit premier dispositif de connexion et de vannes, les autres dites premières vannes de communication étant fermées, puis
3. c. On ferme ladite première vanne de communication entre lesdites première et deuxième conduites flexibles quand ladite première conduite est suffisamment vidée, de préférence sensiblement complètement vidée.

Thus the present invention also provides a method according to the invention wherein said flexible pipes are equipped with a said first connecting device and valves, as defined above, connected to a said second connection device and valves, as defined above, preferably said flexible pipes being floating flexible pipes, and after the transfer of said petroleum liquid product between said support and said vessel preferably LNG carrier, purging of said flexible pipes used for the transfer of liquid product , preferably LNG liquefied gas from said support to a said removal vessel, performing the following successive steps in which:

1. at. Said first and second connection valves are closed, and said first and second connection devices and valves are disconnected from one another, and
2. b. Gas is injected at the first end of a first flexible pipe from said support and at least one said first communication valve is opened between said first flexible pipe and a second flexible pipe assembled to the same said first connection device and valves, the other so-called first communication valves being closed, then
3. vs. Said first communication valve is closed between said first and second flexible pipes when said first pipe is sufficiently emptied, preferably substantially completely emptied.

"Sufficiently emptied" is understood to mean that the internal volume of said duct filled with residual fluid does not represent more than 10% of the total internal volume of said duct, preferably not more than 5%, i.e., an empty internal volume of at least 90%, preferably at least 95%, more preferably at least 98% of its total internal volume.

The method thus makes it possible to evacuate the contents of said first flexible pipe via said second flexible pipe and thus makes it possible, after step c), to have substantially emptied or completely emptied said first flexible pipe. On the other hand, it may still remain in general at least 10% or even up to 15% of internal volume of said second pipe not emptied, even when the internal volume of said first pipe has been completely emptied.

It is particularly difficult to completely empty the second flexible pipe after step c) because the end portion of second flexible pipe corresponding to the substantially vertical portion between the sea level and its access level turntable with which it cooperates remains in general, at least in part, filled with liquid after step c) because the two-phase fluid is moving upwards, but the gravity tends to bring it back naturally to the sea level.

• d. On injecte du gaz depuis le support dans ladite première extrémité de ladite deuxième conduite et on ouvre ladite première vanne de communication entre ladite deuxième conduite et une troisième conduite flexible de plus petit diamètre que ladite deuxième conduite de telle sorte que le débit de gaz de purge soit tel que la vitesse dudit gaz soit supérieure à 1,5m/s de préférence supérieur à 3m/s , de préférence encore supérieur à 5m/s, les autres dites premières vannes de communication étant fermées, et
• e. On ferme ladite première vanne de communication entre lesdites deuxième et troisième conduites quand ladite deuxième conduite est suffisamment vidée, de préférence sensiblement complètement vidée.

Preferably in the transfer process according to the invention, after step c), the said second pipe is completely purged by carrying out the following additional steps:

• d. Gas is injected from the support into said first end of said second conduit and said first communication valve is opened between said second conduit and a third flexible conduit of smaller diameter than said second conduit such that the purge gas flow rate such that the speed of said gas is greater than 1.5 m / s, preferably greater than 3 m / s, more preferably greater than 5 m / s, the other said first communication valves being closed, and
• e. The first communication valve is closed between said second and third conduits when said second conduit is sufficiently emptied, preferably substantially completely emptied.

It is understood that in this embodiment, the internal volume of liquid product contained in said second pipe is entirely evacuated by said third pipe. The fact that said third pipe is of smaller diameter makes it possible to promote complete emptying of said third pipe, in particular at its substantially vertical terminal portion between the sea level and the inlet of its corresponding turntable, after the step e) when said second pipe has been substantially completely emptied. It is particularly advantageous to implement the combination of steps a) to e) to empty all three said first, second and third pipes.

More particularly still, when all of said flexible pipes have been sufficiently purged, said flexible pipes are rewound on their so-called turntables, until the second ends of all of said flexible pipes are out of water, preferably with said first connecting device and valves arriving just below the lowest turntable cooperating with a said flexible pipe.

It is understood that said first valve and connection device remains permanently fixed to said second ends of all of said flexible pipes with which it cooperates, when rewinding said flexible pipes, and said first Connection and valves remain out of water, preferably near the level of the lowest turntable.

Advantageously, said first pipe is wound on a said convex turntable as defined above.

More particularly, at least one of the two said second and third pipes used for the transport of liquid, preferably the two said second and third pipes used for the transport of liquid, is (or are) wound on a said frustoconical tray of concave shape as defined above.

It is understood that any residual liquid in said second and third pipes can thus flow to the tank through said first end of said pipes below by residual natural gravity if necessary when the pipe is wound.

• la figure 1A est une vue de côté d'un support flottant de type FPSO 1, 1-1 de production et de stockage de GNL en phase de déchargement vers un navire, dénommé ici navire enleveur 2 de type méthanier, en configuration dite en tandem, le FPSO étant équipé d'un dispositif de stockage et de guidage de conduite flexible 4 selon l'invention,
• la figure 1B est une vue de côté d'un support 1,1-2 de type FSRU, reposant sur le fond de la mer 21, comportant une unité 1d de regazéification et de production d'électricité et un poste de transformation pour expédition du courant électrique vers la terre, en phase de déchargement depuis un navire de type méthanier, dénommé navire d'approvisionnement, en configuration dite en tandem, ledit support flottant étant équipé d'un dispositif de stockage et de guidage de conduite flexible 4 selon l'invention,
• la figure 1C est une vue de côté d'un support flottant de type FPSO 1-1 de production et de stockage de GNL en phase de déchargement vers un navire enleveur 2 de type méthanier, en configuration dite à couple, le FPSO étant équipé d'un dispositif de stockage et de guidage de conduite flexible 4 selon l'invention,
• la figure 1D est une vue de côté d'un support flottant dans lequel lesdites conduites flexibles sont ré-enroulées sur un dispositif de stockage et de guidage 4 avec un dit premier dispositif de connexion 13-1 hors d'eau.
• la figure 2 est une vue de côté, en coupe partielle du dispositif de stockage et de guidage 4 selon l'invention comportant trois plateaux tournants 4-1 superposés et sur laquelle figure 2 n'est représenté qu'un seul moyen de guidage 10 de conduites flexibles avec poulie en vis-à-vis du plateau tournant central afin que les différents éléments constitutifs dudit moyen de guidage soient mieux visibles,
• la figure 3 est une vue de dessus du dispositif de stockage et de guidage de la figure 2 équipé de trois moyens de guidage 10-1a, 10-1b, 10-1c décalés les uns à côté des autres dans la direction horizontale Y₁Y'₁ parallèle au bordé 1d sur lequel ils sont fixés. Ledit plateau supérieur 4-1a étant représenté sans la partie de conduite qui est normalement enroulée en spirale en continuation de la portion de conduite 3-2 en sortie du plateau afin de mieux représenter les différentes inclinaisons possible des portions de conduite 3-2 en sortie de plateaux,
• la figure 3A représente en vue de dessus un plateau tournant du dispositif de la figure 3 sur lequel on a représenté une conduite flexible 3 enroulée en spirale, la poulie 10-1 étant représentée en coupe selon AA' de la figure 2,
• les figures 4A, 4B et 4C sont des vues de côté d'un plateau tournant présentant une face supérieure de forme tronconique concave (figure 4A), de forme tronconique convexe (figure 4B) ou de forme plane (figure 4C), sur lequel est enroulée en spirale une conduite flexible tournée autour d'un moyen de guidage 10 en sortie dudit plateau stockage,
• les figures 5A et 5B sont des vues de dessus d'un dispositif de connexion et de vannes 13-1 d'un ensemble de trois conduites flexibles comprenant un premier dispositif de connexion et de vannes 13-1 à l'extrémité des trois conduites flexibles connecté à un deuxième dispositif 13-2 de connexion disposé à bord du navire enleveur 2 (figure 5A). Lesdits premier dispositif de connexion et de vannes 13-1 et deuxième dispositif de connexion et de vannes 13-2 étant déconnecté pour réaliser la purge desdites conduites (figure 5B),
• la figure 6 est une vue de face en coupe BB de la figure 5A dudit premier dispositif de connexions et de vannes.
• les figures 7A, 7B, 7C et 7D sont des vues schématisant différentes possibilités de circulation de fluide entre les différentes conduites flexibles lorsque les différentes vannes du premier dispositif de connexion et de vannes 13-1 sont fermées, afin de réaliser la purge desdites conduites flexibles.
• Les figures 8A et 8B représentent une conduite flexible 3b, 3c de transfert de GNL depuis un plateau tournant de forme convexe vers le navire enleveur 2 lors de la purge de ladite conduite (figure 8A) et une conduite flexible de retour de gaz 3a coopérant avec un plateau tournant de forme concave lors de sa purge (figure 8B).

Other features and advantages of the present invention will become more apparent in the light of the detailed description which follows, given in an illustrative and nonlimiting manner, with reference to the drawings in which:

• the Figure 1A is a side view of a floating support type FPSO 1, 1-1 production and storage of LNG unloading phase to a ship, here called vessel 2 remover type LNG, in so-called tandem configuration, the FPSO being equipped with a flexible pipe storage and guidance device 4 according to the invention,
• the Figure 1B is a side view of a FSRU type 1.1-2 support, resting on the bottom of the sea 21, comprising a regasification and power generation unit 1d and a transformer station for sending electric current to the land, in the unloading phase from a vessel of the LNG type, referred to as a supply vessel, in a so-called tandem configuration, said floating support being equipped with a flexible pipe storage and guidance device 4 according to the invention,
• the figure 1C is a side view of a floating support type FPSO 1-1 for the production and storage of LNG in the unloading phase to a vessel 2 remover of LNG type, in the so-called torque configuration, the FPSO being equipped with a device storage and guide of flexible pipe 4 according to the invention,
• the figure 1D is a side view of a floating support in which said flexible conduits are re-wound on a storage and guiding device 4 with a said first device 13-1 connection out of water.
• the figure 2 is a side view, in partial section of the storage and guiding device 4 according to the invention comprising three rotating plates 4-1 superimposed and on which figure 2 only one means for guiding flexible pipes with a pulley opposite the central turntable is shown so that the various elements constituting said guide means are more clearly visible,
• the figure 3 is a top view of the device for storing and guiding the figure 2 equipped with three guide means 10-1a, 10-1b, 10-1c offset next to each other in the horizontal direction Y ₁ Y ' ₁ parallel to the plating 1d on which they are fixed. Said top plate 4-1a being shown without the portion of pipe which is normally spirally wound in continuation of the pipe portion 3-2 at the outlet of the plate to better represent the different inclinations possible of the pipe portions 3-2 output trays,
• the figure 3A represents in top view a turntable of the device of the figure 3 on which there is shown a flexible pipe 3 wound in a spiral, the pulley 10-1 being shown in section along AA 'of the figure 2 ,
• the Figures 4A, 4B and 4C are side views of a turntable having a concave frustoconical upper face ( Figure 4A ), of convex frustoconical shape ( Figure 4B ) or of a flat shape ( figure 4C ), on which is wound in a spiral a flexible pipe turned around a guide means 10 at the output of said storage tray,
• the Figures 5A and 5B are top views of a connection device and valves 13-1 of a set of three flexible pipes comprising a first connection device and valves 13-1 at the end of the three flexible pipes connected to a second connecting device 13-2 disposed on board the removing vessel 2 ( Figure 5A ). Said first connection device and valves 13-1 and second connection device and valves 13-2 being disconnected to purge said conduits ( Figure 5B )
• the figure 6 is a front view in section BB of the Figure 5A said first connecting device and valves.
• the FIGS. 7A, 7B, 7C and 7D are views schematizing different possibilities of fluid circulation between the various flexible pipes when the different valves of the first connection device and valves 13-1 are closed, in order to purge said flexible pipes.
• The Figures 8A and 8B represent a flexible pipe 3b, 3c of LNG transfer from a convex turntable to the removal vessel 2 during the purge of said pipe ( figure 8A ) and a flexible gas return pipe 3a cooperating with a concave rotating plate during its purge ( Figure 8B ).

On the Figure 1A , there is shown in side view a floating support according to the invention 1 FPSO type 1-1 anchored 1a on an open sea gas production field.

Said FPSO has gas treatment and liquefaction equipment 1b and first LNG storage tanks 11 integrated into the hull.

An LNG-type 2 removal vessel is positioned in tandem, substantially in the axis of said FPSO and is connected thereto by a set of three hose lines 3A, 3B and 3C handled by means of a storage device 4 and flexible pipe guidance 3 according to the invention which will be detailed further in the description.

Said flexible pipes 3 are floating flexible pipes of the type manufactured and marketed by Trelleborg (France) consisting essentially of metal or composite armor and vulcanized or thermoplastic elastomers.

Such pipes for the transfer of liquefied gas discharge traditionally has internal diameters of 250 to 600 mm and external diameters of 400 to 1000 mm. They are generally manufactured in lengths of 12m and are assembled together at their ends equipped with flanges to obtain lengths of 120 to 250m. In the same manner, gas gas transfer pipes in the gaseous state between the removing vessel 2 and the floating support 1 as will be explained below, the pipes are of the same total length but advantageously of reduced diameter, 150 to 400mm inside diameter.

In some cases, it is preferred to have in return gas identical lines to the LNG transfer lines, which has an advantage in terms of spare parts stock, because all the elements are then identical.

On the figure 2 , there is shown in side view and in partial section the storage and guiding device 4 of the flexible pipes 3. The storage device consists of a plurality of 3 rotating plates 4-1, 4a, 4b, 4c arranged one above the other, preferably coaxially along the same vertical axis of rotation ZZ '.

The 3 trays 4-1 are supported by a first support structure 5 resting on the bridge 1c of the floating support 1 near a plating 1d at one of its longitudinal ends.

As shown on the figure 3 , the first support structure 5 here comprises 8 vertical posts 5b interconnected by first horizontal beams 5c at different heights and second horizontal beams 5a arranged radially and diametrically between vertical poles 5b diametrically opposed. Said horizontal beams 5a form horizontal bearing structures at three heights different able to support each one of the 3 turntables 4-1.

Each of said rotating plates have in its center an orifice 4-2 and a bearing 4-4, for example a roller bearing, said bearing being partly integral with a said horizontal bearing structure 5a and allowing said plate to be rotated. rotating about its central axis of rotation ZZ 'with a first motor 6 and rollers 4-5 described below.

Each turntable 4-1 is in fact supported at its periphery and in the underside of said trays by a series of rollers 4-5, preferably evenly distributed around the periphery, the supports 4-5a of said rollers 4-5 being integral. of a said horizontal carrier structure 5a.

Each turntable 4-1 is rotated about its vertical axis ZZ 'by means of a first motor 6, preferably hydraulic, driving in rotation an output shaft comprising a gear cooperating with a toothed wheel 6-1 integral with said turntable 4-1 thereby rotating said turntable when said output shaft is rotated.

A central shaft 4-3 is disposed above said port 4-2 of each of said rotating plates. The outer radius of said central shaft 4-3 is greater than the minimum radius of curvature of said flexible pipe to be wound contiguous concentric spiral resting side by side on said turntable. Said central shaft 4-3 is integral with said turntable 4-1.

As shown on the figure 4 a rotary joint 7, of the type known to those skilled in the art, is installed at the axis ZZ 'of each said turntable 4-1.

It consists of a rotary joint itself 7-1 whose upper part is equipped with an upper elbow 7-2 whose end comes against the wall of said central shaft 4-3. The end of the upper elbow 7-2 being sealingly connected at 7a to a first end 3-1 of flexible pipe 3 intended to be wound in a spiral against and around said central drum 4-3 when said turntable 4-1 is rotated. In the lower part of the rotary joint 7-1, it comprises a lower bend 7-3 which remains fixed when said upper bend 7-2 is rotated by rotation of said turntable 4-1. The lower bend 7-3 is itself sealingly connected to an end 8-1 of a transfer pipe 8, the other end of which is connected to a first tank 11 of the FPSO 1, thus making it possible to bring LNG from said first tank 11 of the FPSO 1, is connected to a reliquefaction unit on board the FPSO thus returning gas from said removing vessel 2 to said reliquefaction unit.

The various transfer lines 8 all pass inside the respective central orifices 4-2 of the various plates 4-1.

Each flexible pipe 3, 3a-3b-3c is guided by a guide means 10 of which only one is shown on the figure 2 , each guide means 10 comprising a pulley 10-1 disposed in a substantially vertical axial plane and adapted to rotate on itself in first rotation of horizontal axis Y ₁ Y ₁ '.

The pulley 10-1 has a radius greater than the minimum radius of curvature of said flexible pipe 3 intended to be turned around said pulley.

Said pulleys 10-1, 10-1a, 10-1b, 10-1c are arranged close to and opposite each of said rotating plates 4-1 so that the groove of said pulley at its point the highest reaches substantially at a virtual plane P tangent to the upper face 4-1a, virtual plane P on which rests the pipe portion 3-2 at the output of said turntable.

In other words, the generatrix of the surface of the upper face 4-1a of revolution of said circular rotating plate 4-1 is tangent to the groove of said pulley at its highest point.

In this way, the portion of flexible pipe 3-2 at the outlet of said plate 4-1, that is to say in continuity with the last turn wound on said plateau 4-1 will be more perfectly guided during the winding operations and unwinding of said pipe during the rotation of said plate 4-1 and said pulley 10-1 about its horizontal axis X ₁ X ' ₁ .

Each pulley 10-1 is secured to a second support structure 10-2 comprising a vertical support 10-3 ending at its apex by a stirrup supporting the horizontal hub disposed along the axis of first rotation on itself Y ₁ Y ' ₁ for pulley 10-1 of the figure 3 , said vertical support 10-3 being articulated in second rotation along its vertical axis Z ₁ Z ' ₁ at the top of a fixed pylon 10-4 resting on a structure 10-5 itself secured to the hull of the FPSO 1 at the level of said plating 1d. Because said vertical support 10-3 can be articulated freely in rotation along its vertical axis Z ₁ Z ' ₁ , said pulley 10-1 is able to be articulated in second rotation along said vertical axis Z ₁ Z' ₁ .

On the other hand, the vertical support 10-3 supporting the pulley 10-1 is able to be moved in height to properly adjust the position of the top of the pulley with respect to the plane tangent to the upper face of the plate 4-1 screwed to which she is disposed.

Such a second rotation along the axis Z ₁ Z ' ₁ of said pulley 10-1 will occur as shown in FIG. figure 3 as distance from the center of the plate of the last point of contact of the last turn of the pipe wound on said plate, between two limit points O and M, O being the closest point of the barrel 4 -3 (completely unrolled pipe) and M being the closest point to the periphery of the plate (fully wound pipe) as shown in FIG. figure 3 .

• une première position limite dans laquelle la portion de conduite 3-2 en sortie dudit plateau 4-1 rejoignant l'entrée de ladite poulie 10-1, arrive au niveau d'une dernière spire enroulée en périphérie dudit plateau 4-1 en M,
• une deuxième position limite de dite deuxième rotation de chacune des poulies 10-1 dans laquelle la portion de conduite 3-2 en sortie de plateau arrive au niveau du point O correspondant à la position de ladite première extrémité 3-1 de conduite flexible à proximité du fût central 4-3.

On the same figure 3 , the 3 pulleys 10-1: 10-1a, 10-1b and 10-1c are shifted next to each other in the direction Y ₁ Y ' ₁ horizontal parallel to the plating 1d. On the other hand, the substantially vertical axial planes P1, P2, P3 of the 3 pulleys 10-1a, 10-1b and 10-1c respectively can have a variable inclination α1, α2, α3 respectively with respect to said direction Y ₁ Y ' ₁ . Indeed, said substantially vertical planes axial P1, P2 and P3 of the 3 pulleys can rotate according to a said second rotation of an angle β ₁ , β ₂ or respectively β ₃ between:

• a first limit position in which the portion of pipe 3-2 at the output of said plate 4-1 joining the inlet of said pulley 10-1, arrives at a last turn wound around the periphery of said plate 4-1 in M,
• a second limit position of said second rotation of each of the pulleys 10-1 in which the pipe portion 3-2 at the plateau exit arrives at the point O corresponding to the position of said first end 3-1 of flexible pipe close central shaft 4-3.

The said axial planes P1, P2, P3 of the three pulleys also correspond to the substantially vertical axial planes of the three upstream pipe portions extending between each of said plates and respectively each of said pulleys.

Each pulley 10-1 is preferably motorized by a second motor 10-6, preferably hydraulic, cooperating with a ring gear, not shown, integral with said pulley and allowing to drive in said first rotation on itself around its said horizontal axis Y ₁ Y ' ₁ each of said pulleys 10-1.

Because the different pulleys 10-1 are arranged at a different altitude corresponding to that of said tray 4-1 it serves on the one hand and on the other hand said pulleys 10-1 are arranged next to each other offset in the direction Y ₁ Y ' ₁ , despite the second rotation angles α ₁ , α ₂ , α ₃ of each of the 3 pulleys 10-1a, 10-1b, 10-1c, said pulleys are not in danger of interfere with each other.

As shown on the figure 2 , the curved intermediate portions 3-3 of flexible pipe 3 turned around the pulley 10-1 are continued by a downstream driving portion 3-4 in a substantially vertical position joining the surface 20 of the sea where it floats on a portion 3- 5 of their length towards the ship 2.

As shown on the figure 3 , the vertical downstream portions 3-4 of the various lines 3, 3a, 3b, 3c are offset in a direction Y ₁ Y ' ₁ but remain in substantially vertical and substantially parallel axial planes despite said second rotation along their axis Z ₁ Z _{1 of} said pulleys 10-1a, 10-1b, 10-1c.

On the figure 1C , there is shown an alternative embodiment in which the LNG 2 is arranged in torque of the floating support 1, in this embodiment the floating support 1-1 and the vessel 2 are arranged parallel side by side along their longitudinal edges in their longitudinal directions XX 'and the flexible pipes 3 connecting the device 4 on board the support 1-2 to the ship 2 are arranged above the sea level 20. More particularly, the flexible pipes 3 adopt a configuration in the form of a chain above sea level 20 from the pulley outlets 10-1 at the storage and guidance devices 4 of the floating support 1 to the common valve device 13 on the LNG carrier 2.

As an illustration, a plate 4-1 has a diameter of about 20 m. The height of the storage device 4, that is to say the height of the various posts 5b is about 15 to 20 m for 3 trays 4-1 spaced in height from 4 to 5 m from each other. A central shaft 4-3 will typically have a diameter of 5 to 8 m.

Such a device 4 is particularly suitable for receiving flexible pipes with a diameter of 120 to 600 mm and a length of 120 to 250 m.

Each of said rotating plates 4-1 can be rotated about its axis ZZ 'independently of one another. It is the same for the motorization in said first rotation of said pulleys 10-1. Thus, it is possible to adjust the voltage and the length of each of said flexible pipes 3a, 3b and 3c independently of one another so that said flexible pipes extending between the vertical portions 3-4 at the outlet of the pulleys 10-1 and a common valve device 13 also called connection and purge device, disposed on board the ship 2, to which are connected the different second ends of the various flexible pipes 3a, 3b, 3c remain substantially equal during all the winding operations and unwinding of said flexible pipes. Indeed, the respective diameters of each of said flexible pipes being in general different, it takes a number of different turntable turns to each of said flexible pipes 3a, 3b and 3c to store the same length of flexible pipe.

Once the pipes re-wound on their turntable 4-1, the implementation of an upper face rotating plate 4-1a of concave frustoconical shape 4-1b or of convex frustoconical shape 4-1c as shown in FIGS. Figures 4A and respectively 4B is advantageous to completely purge the residual LNG within said wound pipe which has allowed the transfer of LNG from the floating support 1 to the LNG carrier 2 as a function of the conditions of use of said pipes during their purging as described herein. -after.

The flexible pipes 3b, 3c carrying the liquefied gas LNG stored in a first tank 11 of the support 1 to the vessel 2 have a very large diameter so as to optimize the transfer rate of LNG, while the return gas can be conveyed in a single pipe, generally of smaller diameter, because the pressure losses are considerably lower for gas than for LNG.

It is recalled that LNG liquefied natural gas consists essentially of liquid methane at -165 ° C, and that the removal vessels are made up of LNG tankers that is to say ships carrying LNG gas and whose vessels when they are The voids are in fact filled with gaseous methane, and possibly with nitrogen, from the regasification of LNG. The implementation of these gas return pipes is intended on the one hand to evacuate the gas sky of the second tanks as and when they are filled by LNG from the first tanks on the one hand and the other hand LNG gas regasified during its transfer due to its relative warming. Once returned to the support 1, the gas is reliquefied in LNG.

The connection device and valves 13 and the method of purging the flexible pipes before these are re-wound on their turntable are described below. This purge is necessary firstly to lighten the flexible pipes and facilitate their re-winding but also to prevent damage to said flexible pipes during their re-winding on said turntables, damage that could occur due to their excessive weight in the liquid-filled state, and the presence of seawater ice on their surface or at the connection elements.

1. a) un premier dispositif 13-1 de vannes et de connexions disposées à l'extrémité desdites conduites flexibles 3a, 3b, 3c, comprenant :
   1. i. trois premières portions de conduite rigide 21a, 21b, 21c maintenues en position relative fixe les unes par rapport aux autres parallèlement,
   2. ii. chaque dite première portion de conduite rigide 21a, 21b, 21c comprenant :
      • ▪ à une première extrémité un premier élément de raccordement de conduite 23-1a, 23-1b, 23-1c, constitué d'une partie mâle ou femelle d'un connecteur automatique,
      • ▪ à leur deuxième extrémité 3-6 une bride d'assemblage 31 assemblée à ladite deuxième extrémité 3-6 de chaque dite conduite flexible 3a, 3b, 3c,
      • ▪ entre les deux extrémités de chaque dite première portion de conduite rigide, chacune desdites premières portions de conduite rigide comprend deux dérivations 30 de communication comprenant chacune une première vanne de communication 30ab, 30ac, 30bc, ladite dérivation 30 permettant la communication de chaque dite première portion de conduite rigide avec une des deux autres premières portions de conduites rigides dudit premier dispositif 13-1,
      • ▪ une première vanne de connexion 22a, 22b, 22c située entre ledit premier élément de raccordement 23-1a, 23-1b, 23-1c et ladite dérivation 30 la plus proche de ladite première extrémité dudit premier dispositif 13-1, et
2. b) un deuxième dispositif de connexion et de vannes 13-2 disposé à bord dudit navire enleveur 2 comprenant :
   • ▪ trois deuxièmes portions de conduites rigides 26a, 26b, 26c maintenues en position relative fixe les unes par rapport aux autres parallèlement,
   • ▪ chaque dite deuxième portion de conduite rigide 26a, 26b, 26c communiquant à une de ses extrémités avec une dite deuxième cuve 12 du navire 2 et comprenant à son autre extrémité un premier élément de raccordement complémentaire de conduite 23-2a, 23-2b, 23-2c, lesdits premiers éléments de raccordement complémentaires étant constitués de partie femelle et/ou respectivement mâle de connecteurs automatiques, c'est-à-dire complémentaires d'un dit premier élément de raccordement pour permettre précisément le raccordement 23 entre lesdits premier dispositif 13-1 et deuxième dispositif 13-2,
   • ▪ chaque dite deuxième portion de conduite rigide comprenant en outre une deuxième vanne de connexion 27a, 27b, 27c. L'ensemble desdites premières portions de conduites rigides sont maintenues parallèlement entre elles par un premier support rigide 24 auquel elles sont solidarisées 24a, 24b, 24c. De même l'ensemble desdites deuxièmes portions de conduites rigides 26a, 26b, 26c sont maintenues parallèlement entre elles par un deuxième support rigide 25 auquel elles sont solidarisées en 25a, 25b, 25c.

The connection device and valves 13 shown on the Figures 5A, 5B and 6 includes:

1. a) a first device 13-1 of valves and connections disposed at the end of said flexible conduits 3a, 3b, 3c, comprising:
   1. i. first three rigid pipe portions 21a, 21b, 21c held in relative fixed position relative to each other in parallel,
   2. ii. each said first rigid pipe portion 21a, 21b, 21c comprising:
      • At a first end a first pipe connection element 23-1a, 23-1b, 23-1c, consisting of a male or female part of an automatic connector,
      • At their second end 3-6 an assembly flange 31 assembled to said second end 3-6 of each said flexible pipe 3a, 3b, 3c,
      • Between the two ends of each said first rigid pipe portion, each of said first rigid pipe portions comprises two communication branches 30 each comprising a first communication valve 30ab, 30ac, 30bc, said bypass 30 allowing the communication of each said first rigid pipe portion with one of the other two first rigid pipe portions of said first device 13-1,
      • A first connection valve 22a, 22b, 22c located between said first connecting element 23-1a, 23-1b, 23-1c and said bypass 30 closest to said first end of said first device 13-1, and
2. b) a second connecting device and valves 13-2 disposed on board said removing vessel 2 comprising:
   • ▪ three second portions of rigid pipes 26a, 26b, 26c held in relative position fixed relative to each other in parallel,
   • Each said second rigid pipe portion 26a, 26b, 26c communicating at one of its ends with a said second vessel 12 of the vessel 2 and comprising at its other end a first complementary pipe connecting element 23-2a, 23-2b, 23-2c, said first complementary connecting elements consisting of female and / or male part of automatic connectors, that is to say complementary to a said first connecting element to allow precisely the connection 23 between said first device 13-1 and second device 13-2,
   • ▪ each said second rigid pipe portion further comprising a second connection valve 27a, 27b, 27c. All of said first portions of rigid pipes are held parallel to each other by a first rigid support 24 to which they are secured 24a, 24b, 24c. Similarly all of said second rigid pipe portions 26a, 26b, 26c are held parallel to each other by a second rigid support 25 to which they are secured at 25a, 25b, 25c.

Advantageously, the various valves are ball valves or butterfly valves.

Because all of said first connecting elements are held fixed at a constant distance from each other by said first support 24 to which they are secured at 24a, 24b, 24c and that said first complementary connecting elements are also fixed to constant distance from each other and identical to the distance separating said first connecting elements from each other. The connection between said first device 13-1 and second device 13-2 can be done automatically by actuators not shown remote controlled, and in a single sequence.

On the Figure 5B is shown in plan view, the connectors in the approach phase, before connection, all the valves 22a, 22b, 22c devices 13-1 and 13-2 are closed.

On the Figure 5A , the automatic connectors 23-1 / 23-2 are sealed and the valves 22a-22b-22c and the valves 27a-27b-27c are in the open position, thus allowing the passage from the left to the right of the LNG in the two lines 3b and 3c from the support 1 to the removing vessel 2, and the passage of the methane gas back, from right to left, in the central pipe 3a from the removing vessel 2 to the FPSO1.

For clarity of explanation with reference to Figures 5A-5B , 7A-7B-7C-7D and 8A-8B , LNG transfers are represented by a double-headed arrow, and gas transfers are represented by a single-line arrow, the length of said arrow being proportional to the flow in the respective pipe.

• une vanne 30ac relie les premières portions de conduites 21a et 21c ;
• une vanne 30ab relie les premières portions de conduites 21a et 21b ;
• une vanne 30bc relie les premières portions de conduites 21b et 21c.

The first valve device 13-1 is provided with a third series of communication valves between said first pipe portions 21a-21b-21c arranged as follows:

• a valve 30ac connects the first portions of conduits 21a and 21c;
• a valve 30ab connects the first portions of conduits 21a and 21b;
• a valve 30bc connects the first portions of pipes 21b and 21c.

During LNG transfer operations to the removing vessel 2, the three said valves 30ab, 30ac and 30bc are in the closed position as shown in FIG. Figure 5A .

• on ferme les vannes 22a-22b-22c du premier dispositif de vannes commun 13-1, ainsi que les vannes 27a, 27b, 27c du second dispositif de vannes commun 13-2 à bord du navire enleveur 2, puis
• on déconnecte les dits éléments de raccordement 23 des premier et deuxième dispositifs de vannes 13-1 et 13-2, puis
• on largue les conduites flexibles 3a, 3b, 3c équipées de leur premier dispositif de connexion 13-1, lesquelles conduites flexibles flottent alors à la surface de l'eau 20, puis
• on ouvre une vanne de communication 30bc entre les deux portions de premières conduites rigides 21b, 21c communicant avec les conduites flexibles 3b, respectivement 3c comme représenté sur la figure 7A, puis
• on pressurise depuis le FPSO 1 une première conduite, par exemple la conduite 3b à l'aide de gaz, en général du méthane ou un mélange azote-méthane de manière à pousser le GNL, à une pression P,
• la pression du gaz pousse le GNL dans ladite conduite 3b et le plan de séparation des phases liquide-gaz descend progressivement dans ladite conduite 3d alors que le GNL remonte vers le FPSO par la seconde conduite 3c. Lorsque ledit plan de séparation atteint la partie 3-5 de conduite au niveau de la mer, la conduite flexible 3b est alors sensiblement horizontale et le gaz continue à pousser, mais il se forme alors un mélange diphasique sous pression qui se dirige vers le premier dispositif de vannes 13-1, puis franchit ladite vanne 30bc' et s'en retourne vers le FPSO à travers la conduite flexible 3c. Le mélange diphasique comporte des bulles de petit diamètre au niveau de la surface de la mer, mais dès qu'elles atteignent la portion verticale 3-4 de ladite conduite 3c, du fait que la pression hydrostatique diminue au fur et à mesure de la remontée vers le pont du FPSO, les bulles grossissent et la densité apparente du mélange diminue, ce qui accélère d'autant la vitesse de la colonne montante diphasique, améliorant de ce fait l'entraînement de la phase liquide, puis
• lorsque les parties horizontales 3-5 des deux conduites flexibles 3b et 3c sont sensiblement vidées, c'est à dire sont sensiblement remplies de gaz, on accélère le débit de gaz depuis le FPSO dans la conduite 3b de manière à augmenter radicalement la perturbation de l'écoulement diphasique dans la portion sensiblement verticale 3-4 de la deuxième conduite 3c, ce qui a pour effet d'entraîner de manière optimale les particules de GNL, permettant de vider au moins 85%, en pratique de 85 à 95%, du volume interne des deux conduites 3b-3c.

In order not to let the flexible pipes 3a, 3b, 3c float on the sea between two transfers of LNG, which may represent a duration of several weeks, the flexible pipes are rewound on their turntables 4-1 after the have, preferably, purged as follows:

• the valves 22a-22b-22c of the first common valve device 13-1 are closed, as are the valves 27a, 27b, 27c of the second common valve device 13-2 on board the removing vessel 2, and then
• said connection elements 23 are disconnected from the first and second valve devices 13-1 and 13-2, and then
• the flexible pipes 3a, 3b, 3c with their first connecting device 13-1 are dropped, which flexible pipes then float on the surface of the water 20, then
• a communication valve 30bc is opened between the two portions of first rigid pipes 21b, 21c communicating with the flexible pipes 3b, respectively 3c as shown in FIG. Figure 7A then
• a first pipe is pressurized from the FPSO 1, for example the pipe 3b using gas, generally methane or a nitrogen-methane mixture so as to push the LNG to a pressure P,
• the pressure of the gas pushes the LNG in said pipe 3b and the plane separation of the liquid-gas phase progressively descends in said 3d pipe while the LNG goes back to the FPSO by the second pipe 3c. When said separation plane reaches the portion 3-5 of pipe at sea level, the flexible pipe 3b is then substantially horizontal and the gas continues to push, but it then forms a two-phase pressure mixture which goes to the first valve device 13-1, then crosses said valve 30bc 'and returns to the FPSO through the flexible pipe 3c. The diphasic mixture comprises small diameter bubbles at the sea surface, but as soon as they reach the vertical portion 3-4 of said pipe 3c, because the hydrostatic pressure decreases as the lift towards the FPSO bridge, the bubbles increase and the bulk density of the mixture decreases, which accelerates the speed of the two-phase riser, thus improving the entrainment of the liquid phase, then
• when the horizontal portions 3-5 of the two flexible pipes 3b and 3c are substantially emptied, that is to say they are substantially filled with gas, the gas flow rate is accelerated from the FPSO in the pipe 3b so as to radically increase the disturbance of the two-phase flow in the substantially vertical portion 3-4 of the second pipe 3c, which has the effect of optimally driving the LNG particles, making it possible to empty at least 85%, in practice from 85 to 95%, the internal volume of the two lines 3b-3c.

More particularly, in general the pipe 3b is empty but there is still liquid in the pipe 3c at a rate of 10 to 20% of the internal volume of the pipe 3c, especially in its substantially vertical portion 3-4 as shown Figure 8B .

The purge process described above in connection with the Figure 7A is relatively fast so for pipes from 100 to 150 m the purge can be operated for a duration of 1/2 to 1 hour whereas it would be necessary more than 24 hours for the LNG contained in the pipes to heat up and gasify.

In the Figures 7B and 7C , there is shown a more complete purge mode of the flexible pipes 3b and 3c in which a first flexible pipe 3c is purged, by injecting the gas through the gas return pipe 3a. For this purpose, the valve 30ac is opened, the valves 30ab and 30bc being closed, as shown in FIG. Figure 7B . The purge is stopped when most of the LNG, ie at least 85% of the LNG of the 3C line has been recovered on board the FPSO. Then the valve 30ac is closed and the valve 30ab is opened, which has the effect of purging the second flexible pipe 3b in the same way, ie up to at least 85% of the LNG of the pipe 3b has been recovered on board the FPSO. Finally, as represented on the Figure 7C the injection direction of the gas is reversed which is injected directly into the two flexible pipes 3b and 3c, the LNG then rising through the pipe 3a. This arrangement has a great advantage in the case where said gas return pipe 3a is of smaller diameter. Indeed, to raise the two-phase mixture in the vertical portion 3-4 of pipe 3a, the gas flow in the pipes 3b and 3c required is considerably lower than in the case described above with reference to the Figure 5A where the two flexible pipes 3b and 3c are generally of the same diameter so as to optimize the LNG transfer rate.

To ensure optimum emptying of the upward vertical duct portion, it is necessary to create a purge gas velocity greater than 1.5 m / s, preferably greater than 3 m / s, more preferably greater than 5 m / s. Thus, considering a pipe of reduced diameter, the flow rate of gas necessary to obtain this speed decreases as the square of the ratio of the diameters, which illustrates the advantageous nature of having a gas return line of smaller diameter.

To further improve this purge phase of the lines 3b and 3c, it will be advantageously carried out sequentially as shown. Figure 7D with regard to the complete bleeding of line 3c in closing the valve 30ab to finalize the purge of the flexible pipe 3c, then opening the same valve 30ab and closing the valve 30ac to finalize the purge of the flexible pipe 3c by injecting gas into the pipe 3c to evacuate the residual LNG by driving 3a.

On the figure 8A the flexible pipe 3b is shown in side view from its storage tray to sea level. The convex storage tray 4-1b has a convex frustoconical upper face with a negative angle α, which is advantageous for the purge phase of the flexible pipes, because in the description of the invention with reference to the Figure 7A it is by this conduct that the purge gas is injected and the conicity of the storage tray, the pipe empties naturally down.

On the Figure 8B , the flexible pipe 3b is shown in side view from its storage tray to sea level. The concave storage tray 4-1c has a concave frustoconical upper face with a positive angle α, which is advantageous for the purge phase of the flexible pipes, because in the description of the invention with reference to Figures 7A and 7B it is by this conduct that the two-phase mixture rises towards the FPSO, and from the conicity of the storage tray, the spirally stored pipe on said conical plate empties naturally to the rotary joint 7 located at the axis ZZ ' of the plateau. On this same Figure 8B , said pipe is shown almost empty in its horizontal part 3-5, the two-phase mixture in the substantially vertical portion 3-4 having small diameter bubbles at the bottom and increasing diameters as the ascension to the storage tray, the mixture in the pipe.

For a 3-4 section pipe height of 30 to 35 m corresponding to a pressure differential of 1.5 to 2 bars, in the lower part will be a diameter of 5 to 10 mm and in the upper part, because of the pressure differential, a much larger diameter of several centimeters or decimetres, which has the effect of reducing the density of the two-phase mixture throughout the fluid column and therefore favors its training and evacuation at the turntable: - this phenomenon is known as the Anglo-Saxon "gas-lift".

In the purge mode described with reference to Figures 7C and 7D , the storage tray of the gas return line ( Figure 7C ) 3a ( Figure 7D ) is advantageously concave conical type with a positive angle α.

• première étape de purge d'une conduite 3b par injection de gaz dans la conduite 3b conduisant à une purge complète de la conduite 3b mais une purge partielle seulement de la conduite 3c compte tenu du gaz GNL résiduel notamment dans la partie 3-4 de la conduite 3c dans un mode de mise en oeuvre des différentes vannes tel que décrit dans la figure 7A. Au terme de cette première étape, la conduite 3c retient encore environ 15% de son volume interne rempli de GNL.
• puis on ferme la vanne 30bc et on ouvre la vanne 30ac,
• la deuxième étape de purge est réalisée par injection de gaz dans la conduite 3c et évacuation par la conduite de retour de gaz 3a de plus petit diamètre en mettant en oeuvre les différentes vannes comme décrit sur la figure 7C. Du fait que l'évacuation se fait par une conduite 3a de plus petit diamètre, le débit de gaz nécessaire dans la conduite 3c est considérablement réduit pour obtenir la vitesse optimale du fluide diphasique correspondant à une vitesse du gaz supérieure à 1.5m/s, de préférence supérieure à 3m/s, de préférence encore supérieure à 5m/s. Du fait que la section de la conduite 3a soit plus faible, le transfert de liquide se fait plus lentement mais la purge s'en trouve radicalement améliorée en termes de pourcentage ultime de purge de liquide diphasique et de durée globale.

In the case where the gas return pipe has a smaller internal diameter than that of the LNG pipes, the preferred purge method will comprise the following two purge steps:

• first step of purging a pipe 3b by gas injection in the pipe 3b leading to a complete purge of the pipe 3b but a partial purge only of the pipe 3c taking into account the residual LNG gas in particular in part 3-4 of the 3c in one embodiment of the various valves as described in the Figure 7A . At the end of this first step, the pipe 3c still retains about 15% of its internal volume filled with LNG.
• then the valve 30bc is closed and the valve 30ac is opened,
• the second purge step is carried out by injecting gas into the pipe 3c and discharging through the gas return pipe 3a of smaller diameter by implementing the various valves as described in the description. Figure 7C . Since the evacuation is via a pipe 3a of smaller diameter, the necessary gas flow in the pipe 3c is considerably reduced to obtain the optimum speed of the two-phase fluid corresponding to a gas velocity greater than 1.5 m / s, preferably greater than 3m / s, more preferably greater than 5m / s. Because the section of the pipe 3a is smaller, the transfer of liquid is slower but the purge is radically improved in terms of the ultimate percentage of two-phase liquid purge and overall duration.

After purging the three lines 3a, 3b, 3c, they are rewound on their respective turntables until said first connecting device 13-1 reaches above the level of the water particularly substantially below the turntable lower than that of the flexible pipes joined by the device 13-1 as shown in FIG. figure 1D , the first connecting device 13-1 can thus remain permanently at said second end 3-6 of said pipes 3a, 3b, 3c joined by said first device 13-1.

• deux conduites flexibles de GNL de diamètre interne 500mm et de diamètre externe 900mm, chacune des conduites mesure 216m et est constituée de 18 longueurs identiques de 12m chacune, assemblée par brides, pesant 300kg/m à l'état vide,
• une conduite flexible de retour de gaz de diamètre interne 250mm et de diamètre externe 400mm, chacune des conduites mesure 216m et est constituée de 18 longueurs identiques de 12m chacune, assemblée par brides, pesant 125kg/m à l'état vide,
• un dispositif de connexion et de vannes 13 équipé de vannes 22 à boisseaux sphériques de diamètre interne 500mm pour le GNL et de 250mm pour le retour de gaz, les vannes 30ab-30ac-30bc étant des vannes papillon de diamètre de passage 250mm, pesant environ 20 tonnes,
• de trois plateaux de stockage 4 motorisés de 23m de diamètre externe et de diamètre de fût 5m, de trois poulies motorisées de diamètre de gorge 5m et de leur structures de supportage, l'ensemble pesant environ 1000 tonnes.

By way of example, a transfer device according to the invention comprises:

• two flexible LNG pipes of 500mm internal diameter and 900mm external diameter, each pipe measures 216m and consists of 18 identical lengths of 12m each, assembled by flanges, weighing 300kg / m in the empty state,
• a flexible gas return pipe with an internal diameter of 250mm and an external diameter of 400mm, each pipe measures 216m and consists of 18 identical lengths of 12m each, assembled by flanges, weighing 125kg / m in the empty state,
• a connection and valve device 13 equipped with ball valve valves 22 of internal diameter 500mm for LNG and 250mm for gas return, the valves 30ab-30ac-30bc being butterfly valves with a passage diameter of 250mm, weighing about 20 tons,
• three motorized storage trays 4 motorized 23m external diameter and drum diameter 5m, three motorized pulleys 5m throat diameter and their supporting structures, the whole weighing about 1000 tons.

The pipe purge procedure performed with a gas velocity of 4m / s under these conditions represents an overall duration of 30 to 45 minutes to reach an overall LNG balance less than 1% of the volume. This represents approximately 425 liters of residual LNG which will then produce 250m ³ of gaseous methane, which will subsequently be reliqued onboard the FPSO.

Claims (20)

1. A support (1) able to be installed at sea, in grounded or floating manner (1-2, 1-1), said support being fitted on its surface with a storage and guide device (4) for storing and guiding flexible pipes (3, 3a-3b-3c) and suitable for storing and guiding a plurality of said flexible pipes, and preferably at least three of them, the support, the storage and guide device comprising:

   • a first carrier structure (5) resting on or secured to the deck (1c) of said support (1) close to a side (1d) of said support (1), said first carrier structure (5) supporting a plurality of circular turntables (4-1) arranged one above another;

   • each of said turntables (4-1, 4a, 4b, 4c) being suitable for being driven in rotation in powered manner by a first motor (6) about a vertical central axis ZZ' independently of one another, preferably about the same vertical central axis ZZ', each turntable having a central orifice (4-2) surmounted by a central cylinder (4-3) against and around which a said flexible pipe (3, 3a, 3b, 3c) can be wound in concentric juxtaposed spiral turns of increasing diameter resting on the top face (4-1a) of said turntable, said central orifice (4-2) of said turntable being fitted with a rotary joint coupling (7) suitable for providing coupling between firstly a first end (3-1) that is closest to said central cylinder of a flexible pipe wound around said flexible cylinder, said first pipe end (3-1) being suitable for being driven in rotation together with said turntable, and secondly an end (8-1) of a stationary transfer pipe (8) having its other end in communication with at least one first tank (11) within said support (1); and

   • a plurality of guide means (10, 10a, 10b, 10c), each said guide means being suitable for guiding the portion (3-2) of said pipe leaving a respective one of each of said turntables in continuity with the portion of pipe wound on said turntable, in such a manner that the various said pipe portions (3-2) leaving the various turntables are arranged in straight lines, being offset in different positions along a horizontal direction Y₁Y'₁ parallel to said side, at different heights, and capable of adopting different orientations (α1, α2, α3) for their vertical axial planes (P1, P2, P3) relative to said horizontal direction Y₁Y₁' parallel to said side (1d).
2. A support (1) according to claim 1, characterized in that at least one said flexible pipe (3) is wound against and around a said central cylinder (4-3) in concentric juxtaposed spiral turns of increasing diameters resting on said turntable (4-1), said central cylinder presenting a radius greater than the minimum radius of curvature of said flexible pipe, there being at least three flexible pipes wound respectively on at least three said turntables, including at least one flexible pipe of diameter smaller than the others.
3. A support (1) according to claim 1 or claim 2, characterized in that each guide means is arranged at a different height facing a respective one of each of said turntables so as to be suitable for supporting an intermediate curved pipe portion (3-3) between a downstream portion (3-4) of said pipe in a substantially vertical position beside said side (1d) and a said upstream pipe portion leaving the turntable (3-2) in continuity with the wound pipe portion resting on a said turntable, said upstream pipe portion (3-2) leaving the turntable extending on a virtual plane P that is substantially tangential to the surface of the top face (4-1a) of said turntable on which said wound pipe portion is wound, the various downstream pipe portions (4-4) in substantially vertical positions beside said side being arranged in positions that are offset relative to one another in a said direction Y₂Y₂' parallel to said side on leaving said sheaves.
4. A support according to claim 3, characterized in that each said guide means (10) comprises a sheave (10-1) mounted to revolve about a horizontal first axis of rotation Y₁Y₁', said sheave also being suitable for swiveling about a vertical second axis of rotation Z₁Z₁' extending along a diameter of the sheave, said first axis of rotation about which each said sheave revolves being controlled by a second motor (10-6), synchronously with said first motor (6) of each said turntable (4-1).
5. A support (1) according to claim 4, characterized in that the various sheaves (10a, 10b, 10c) are arranged offset side by side relative to one another in said horizontal direction Y₁Y'₁ parallel to said side at different heights, the top of each sheave being positioned substantially level with a plane P tangential to the top face (4-1a) of a said turntable (4-1).
6. A support according to claim 5, characterized in that each sheave is supported by a second carrier structure (10-2) arranged outside said support and fastened to a common side (1d) at a different position in a said horizontal direction Y₁Y₁' parallel to said side, each sheave being mounted to swivel about said vertical second axis of rotation Z₁Z₁' relative to a portion (10-4, 10-5) of its said second carrier structure fastened to said side (1d).
7. A support (1) according to any one of claims 1 to 6, characterized in that each said turntable (4-1) includes or co-operates on its under face with wheels (4-5) suitable for co-operating with or respectively supported by elements (5a) of said carrier structure, and each said turntable including a bearing (4-4) at said central orifice, the bearing being secured to said carrier structure (5) and being suitable for enabling said turntable to rotate relative to said first carrier structure (5).
8. A support (1) according to any one of claims 1 to 7, characterized in that at least one said turntable (4-1d) presents a top face (4-1a) that is plane and horizontal.
9. A support (1) according to any one of claims 1 to 7, characterized in that at least one said turntable (4-1c) presents a top face of convex frustoconical shape, with an angle γ at the apex preferably lying in the range 160° to 178°.
10. A support (1) according to any one of claims 1 to 7, characterized in that at least one said turntable (4-1b) presents a top face (4-1a) of concave frustoconical shape, with an angle γ at the apex preferably lying in the range 160° to 178°.
11. A support (1) according to any one of claims 1 to 10, characterized in that it is fitted with a plurality, n, of flexible pipes (3a, 3b, 3c) each co-operating at its said first end (3-1) with a respective said turntable, said flexible pipes being connected together at their second ends (3-6) by a first connection and valve device (13-1) having n preferably rigid first pipe portions (21a, 21b, 21c) held in fixed positions relative to one another, n being an integer not less than 3, each said first pipe portion (21a, 21b, 21c) comprising:

    · at a first end, a first pipe coupling element (23-1a, 23-1b, 23-1c); and

    · at its second end, a second coupling element assembled to the second end (3-6) of a said flexible pipe; and

    · each said first pipe portion (21a, 21b, 21c) including, between its two ends n-1 branch connections (30) enabling it to communicate with respective ones of the n-1 other said first rigid pipe portions, each said branch connection (30) including a first communication valve (30ab, 30bc, 30ac);

    · a first connection valve (22a, 22b, 22c) situated between said first coupling element (23-1a, 23-1b, 23-1c) and said branch connection (30);

    · said first pipe portions being held parallel by a first rigid support (24) to which they are secured.
12. A support (1) according to claim 11, characterized in that said flexible pipes extend or are suitable for extending between said support (1) and a ship (2) arranged alongside said support (1, 1-1, 1-2) or in tandem facing said side (1d), and said first connection and valve device (13-1) is connected to a second connection and valve device (13-2) arranged or suitable for being arranged on board said ship (2), said second connection and valve device (13-2) comprising:

    · n rigid second pipe portions (26a, 26b, 26c);

    · each said second pipe portion (26a, 26b, 26c) communicating at one of its ends with a said second tank (12) and including at its other end a first complementary pipe coupling element (23-2a, 23-2b, 23-2c), said first complementary coupling element being suitable for co-operating in reversible coupling (23) with a said first coupling element (23-1a, 23-1b, 23-1c);

    · said second pipe portions (26a, 26b, 26c) being held in parallel fixed positions relative to one another so as to enable said first complementary coupling element (23-2a, 23-2b, 23-2c) to be coupled with said first coupling element (23-1a, 23-1b, 23-1c);

    · each said second pipe portion (26a, 26b, 26c) having a second connection valve (27a, 27b, 27c) suitable for allowing or preventing fluid from flowing in said second pipe portion towards or from said first complementary coupling element when open or closed, respectively;

    · said second pipe portions preferably being held parallel to one another by a second rigid support (25) to which they are secured.
13. A method of transferring a liquid or gaseous petroleum fluid, wherein a said petroleum fluid is transferred via at least two flexible pipes (3, 3a, 3b, 3c), extending between a said support (1) according to any one of claims 1 to 12 and a ship (2) arranged alongside or in tandem adjacent to said floating support (1) facing said side (1d), said flexible pipes (3) being guided with the help of a said storage and guide device (4).
14. A method according to claim 13, characterized in that said flexible pipes are floating pipes, floating on the surface over a fraction (3-5) of the distance between said support (1) and said ship (2).
15. A method according to claim 13 or claim 14, characterized in that use is made of at least two first and second flexible pipes (3b, 3c), within which liquefied gas is transferred between said floating support and at least one second tank (12) of said ship (2), and of a third flexible pipe (3a), of diameter smaller than the diameter of said first and second flexible pipes, within which gas corresponding to the gas ceiling of the second tank is transferred between a said second tank (12) to a first tank within said floating support or to a liquefaction unit (1b) on a said support prior to being transferred to a said first tank (11).
16. A method according to any one of claims 13 to 15, characterized in that said flexible pipes are fitted with a first connection and valve device (13-1) as defined in claim 11 and connected to a said second connection and valve device (13-2) as defined in claim 12, said flexible pipes being floating flexible pipes, and said floating flexible pipes (3b, 3c) that have been used for transferring liquid natural gas LNG from said support (1) to a said ship (2) are purged by performing the following successive steps:

    a. closing said first and second connection valves (22a-22b-22c, 27a-27b-27c), and disconnecting said first and second connection and valve devices (13-1, 13-2) from each other;

    b. injecting gas into the first end (3-1) of a first flexible pipe (3b) from said support (1) and opening at least one said first communication valve (30bc) between said first flexible pipe (3b) and a second flexible pipe (3c) assembled to the same said first connection and valve device (13-1), the other said first communication valves (30ac, 30ab) being closed; and then

    c. closing said first communication valve (30bc) between said first and second flexible pipes (3b, 3c) when said first pipe (3b) has been emptied sufficiently.
17. A method according to claim 16, characterized in that after step c), said second pipe (3c) is purged completely by performing the following successive steps:

    d. injecting gas from the support (1) into said first end (3-1) of said second pipe (3c) and opening said first communication valve (30ac) between said second pipe (3c) and a third flexible pipe (3a) of smaller diameter than said second pipe so that the flow rate of purge gas is such that the speed of said gas is greater than 1.5 m/s, said other first communication valves (30ab, 30bc) being closed; and

    e. closing said first communication valve (30ac) between said second and third pipes (3c, 3a) when said second pipe (3c) has been emptied sufficiently.
18. A method according to claim 16 or claim 17, characterized in that when all of said flexible pipes have been purged sufficiently, said flexible pipes are rewound onto their said turntables until the second ends (3-6) of all of said flexible pipes are above water.
19. A method according to claim 18, characterized in that said first pipe (3b) is wound on a said convex turntable as defined in claim 9.
20. A method according to claim 18 or claim 19, characterized in that at least one of said second and third flexible pipes (3c, 3a) used for transporting liquid is wound on a said frustoconical turntable of concave shape as defined in claim 10.

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