OA18195A - Deformable coupling device for underwater pipes - Google Patents

Abstract

The invention relates to a deformable coupling device intended for connecting together a seabed underwater pipe (14) for carrying a fluid and a rising underwater pipe (18) extending towards a sea surface (12), in order to be able to push said fluid to said sea surface (12), said coupling device having two opposing ends, while said seabed underwater pipe (14) has a downstream end (32) and said rising underwater pipe (18) has an upstream end (38), said opposing ends being intended for being coupled to the upstream and downstream ends, respectively. The device comprises a sealed sheath and at least one reinforcement wire wound in a helix around said sealed sheath such as to form a flexible pipe (48), and it includes at least one float (50) connected to said flexible pipe (48), such as to be able to shape said flexible pipe according to a bell-shaped curve in relation to said seabed (10).

Description

Deformable coupling device for underwater pipes

This invention relates to a déformable coupling device intended to connect an underwater flow-line pipe and an underwater riser.

One envisaged field of application is that of the transport of fluids such as gas, water or hydrocarbons in an offshore environment.

Known facilities comprise a sea-bed pipe, currently known as a flow line in English, and a rising underwater pipe, also known as a riser through which fluid on leaving the flow line is conducted from the seabed to the surface close to the seabed, or conversely from the surface to the inlet to the flow line.

The riser has a lower extremity anchored on the seabed and is suspended through its upper extremity from a float immersed below the surface of the marine environment so as to avoid being affected by surface currents. Nevertheless hydrocarbons are being extracted from increasingly deeper seabed depths and as a conséquence risers are caused to move and pivot substantially about their lower extremities. In addition to this, pipes are caused to move in rotation about their axes. Furthermore underwater flow line pipes are also caused to move, in particular longitudinally, among other things because of the thermal changes which they undergo. The fluid that underwater pipes carry is in fact to a greater or lesser extent hot in comparison with the température of the bottom. As a resuit pipes tend to elongate substantially when fluid is flowing within them, while they tend to shorten when flow stops.

As a conséquence a déformable coupling device has to be provided between the lower extremity of the underwater riser and the underwater extremity of the flow line pipe to ensure that the two pipes remain joined despite the movements by one and/or the other.

- 2 Reference may be made to document WO 2014/043126, which relates to a U-shaped tubular coupling device allowing relative movement between the riser and the flow line without disturbing the flow of hydrocarbon. The U-shaped pipe coupling comprises a U-shaped métal tube which can deform longitudinally in the médian plane defined by the U-shape, but also outside the plane in order to allow the riser to rotate about its own axis.

However the alternation of stresses acting on the U-shaped coupling cause the said coupling to deteriorate over time. In addition to this, seabed facilities tend to be covered by bottom sédiments, and their burial makes their repair or partial or even total replacement even more difficult.

Also, a problem which arises and which this invention is intended to overcome is that of providing a coupling device which remains intact over time, and which is also less or not at ail subject to burial.

With this object, and in accordance with a first object, the présent invention provides a déformable coupling device intended to connect together an underwater flow line extending along a horizontal component over a seabed to carry a fluid and an underwater riser extending from said seabed, in accordance with a vertical component, towards a sea surface, so as to be able to carry said fluid between said sea bottom and said surface, said coupling device having two opposite extremities, while said underwater flow line has a downstream extremity and said underwater riser has an upstream extremity, said opposite extremities being intended to be connected to said downstream and upstream extremities respectively. The déformable coupling device comprises a leaktight sheath of polymer material and at least one reinforcement wire wound in a hélix around said leaktight sheath to form a flexible pipe, and said device comprises at least one float connected to said

- 3 flexible pipe so as to shape said flexible pipe into a bell-shaped curve with respect to the seabed between said upstream and downstream extremities.

Thus one characteristic of the invention lies in making use of a déformable coupling device, which is no longer rigid, but flexible, made from a leaktight sheath and at least one reinforcing wire wound in a hélix around that sheath. Also the flexible coupling so formed is provided with at least one float to keep it away from the seabed. In this way, despite relative movements between the riser and the flow line at their upstream and downstream extremities respectively, the flexible pipe is capable of deforming while remaining intact, that is to say without experiencing any wear and/or détérioration likely to cause a malfunction. This is because the polymer material of the sheath and the at least one reinforcing wire deform respectively within their ranges of elastic deformation and do so unlike U-shaped pipe couplings where the métal material can also be deformed within its range of plastic deformation. In this case détérioration of the material occurs very much more quickly.

It will be noted that fluid can also be transported from the seabed to the surface, in the case where it is for example a hydrocarbon, or from the surface to the said seabed when it is for example pressurized water.

In addition to this, because of the float which holds the flexible pipe in a bell-shaped curve above the seabed, and as a conséquence in a position away from it, burial is very much less likely and takes very much more time, and as a resuit it is easier to act in order to replace it if necessary.

In accordance with one particularly advantageous embodiment of the invention the coupling device comprises a plurality of annular floats located close together around said flexible pipe. In this way the flexible pipe expériences tensile forces towards the

- 4 surface at different points regularly spaced apart, allowing the said flexible pipe to deform in a regular way, the radius of curvature adopted by the said flexible pipe in the context of this deformation being strictly greater than a minimum radius of curvature at any point along said flexible pipe. In fact the flexible pipe may be curved to a minimum radius of curvature below which deformation is irréversible. Also, the use of annular floats, formed of sleeves within which the leaktight sheath and said at least one reinforcing wire wound around it extend, make it possible to obtain a relatively compact and unencumbering ballasting effect. This characteristic offers an advantage, because the area located around the lower extremity of the riser on the sea bottom is generally very cluttered.

In addition to this, said underwater riser has guide members around said upstream extremity, a first extremity of the said opposite extremities of said flexible pipe is equipped with a connector intended to be guided towards said upstream extremity by said guide means. In fact the connection operation proper requires the use of an underwater robot, which then draws said first extremity of the flexible pipe to the upstream extremity of the riser. In order to facilitate this connection, and to facilitate control of the underwater robot, the guide means converge towards the upstream extremity and the connector can make a sliding fit with these in order to reach the upstream extremity.

Also said upstream extremity of said underwater riser advantageously comprises, according to a first variant, a connection coupling intended to be orientated substantially horizontally. In this way the first extremity of the flexible pipe can easily be offered up and connected using a latéral approach in relation to the riser, using an underwater robot.

According to a second variant embodiment said upstream extremity of said underwater riser comprises a

- 5 connection coupling which is intended to be orientated substantially vertically. Also the connecting coupling is either orientated towards the surface, in which case it is U-shaped, or orientated towards the seabed and extends longitudinally as an extension of the upstream extremity.

Furthermore the said first extremity of said opposite extremities of said flexible pipe preferably comprises a coupling incorporâting an elbow. The connector thus has two arms which are inclined towards each other at an angle of between for example 110° and 130°.

In this way the first extremity of the flexible pipe may be held in a manner in which it is inclined in relation to the horizontal, as well as in the first or second aforesaid embodiment in which the connection coupling is U-shaped, provided that the connector is adjusted as a conséquence.

According to the second variant, in which the coupling is orientated towards the seabed, the connector is itself substantially U-shaped. The two arms of the connector are however inclined with respect to each other in such a way that the first extremity of the flexible pipe makes an angle of less than 90° with respect to the horizontal.

In accordance with a variant embodiment the coupling device also comprises curvature-limiting sleeves mounted around said flexible pipe in the vicinity of said opposing extremities. The curvaturelimiting sleeves comprise métal and/or polymer rings that are imbricated one within another in the manner of a vertébral column or connected in pairs by means of rods. As a resuit deformations of the flexible pipe in the vicinity of its extremities, which are held in a fixed position, at the upstream extremity of the riser and the extremity of the flow line respectively, are limited to a given radius of curvature that is greater than the minimum radius of curvature.

said length L minimum radius which is at a

According minimum radius embodiment of

to	one f
the	invention
of	curvature
is	between 2

icularly advantageous said flexible pipe has a

MBR and a length L, and π and 5/2 π times said of curvature MBR. Thus a coupling device sufficient distance from the seabed and can overcome the deformations due to relative movements of the riser and flow line without détérioration is obtained.

In accordance invention, said at with a preferred embodiment of the least one reinforcing wire is wound in a hélix so as to leaktight sheath.

As polymer material is form touching turns around said a resuit the leaktight sheath of perfectly protected within the turns of said at least one reinforcing wire. And in addition to this the turns may be caused to move with respect to each other while remaining within the range of elastic deformation of said at least one reinforcing wire.

It will be noted that the flexible pipe of the coupling device is essentially exposed to very little to axial stresses.

radial stresses, and

As a resuit there is no need to provide a layer of reinforcernent circumstances traction against traction. However, in some where the flexible pipe may undergo such forces, at least one additional layer of traction reinforcernent turns of said at least is applied around the touching one reinforcing wire wound in a closely wound hélix.

The additional layer then comprises a plurality of reinforcing wires wound in open turns. In addition to this, under other operating circumstances a flexible complementary reinforcing pipe wires having wound at in least two a closely wound hélix is used.

device

Advantageously the coupling an external protective sheath extending least one reinforcing wire wound into a way the leaktight sheath of polymer material is wholly also comprises around said at hélix. In this

- 7 protected from hydrostatic pressure. In fact this pressure is taken up by the turns of said at least one reinforcing wire onto which the outer protective sheath is applied. The latter is itself advantageously constructed of polymer material.

In addition to this, the coupling device comprises an automatic connection coupling intended to be mounted on said upstream extremity and an automatic connecting end fitting mounted on said first extremity of said opposing extremities, said automatic connecting end being intended to engage in said automatic connection coupling. Thus when the coupling device is put into use, the underwater robot will engage the connecting end fitting within the automatic connection coupling to make a leaktight connection and also to hold them together in a fixed position.

Furthermore said downstream extremity of said underwater flow line has in accordance with one embodiment a downstream end which is orientated substantially vertically. As a resuit the flexible pipe is better protected from deformations when the downstream extremity of the underwater flow line is caused to move with great amplitude.

According to another object the présent invention provides a method for connecting an underwater flow line extending over a seabed along a horizontal component to carry a fluid and an underwater riser extending from said seabed, along a vertical component, towards a sea surface, to be able to carry said fluid between said sea bottom and said sea surface, said underwater flow line having a downstream extremity and said underwater riser having an upstream extremity, the method being of the type comprising the following stages: 1) a extremities is are connected respect downstream extremities;

the to in two opposite extremities device comprising a leaktight sheath of polymer having opposing said upstream and stage 1) , a coupling

- 8 material and at least one reinforcing wire wound around said leaktight sheath in a hélix is provided to form a flexible pipe and secondly at least one float connected to said flexible pipe, whereas in stage 2), said opposite extremities are connected respectively to said upstream and downstream extremities so that said flexible pipe can be shaped according to a bell-shaped curve in relation to said seabed between said upstream and downstream extremities.

Thus one other advantageous characteristic of the invention lies in the method of connecting the underwater flow line and riser by means of a coupling device comprising said flexible pipe. In fact connection is made easier thanks to the flexibility of the coupling device.

According to one particularly advantageous embodiment, in stage 2) one of said opposite extremities is connected to said downstream extremity of said underwater flow line and the other of said opposing extremities and said upstream extremity are connected by means of an upstream pulling cable so as to draw said other opposite extremities towards said upstream extremity. Thus connection is facilitated by pulling on upstream pulling cable, using a winch installed at said upstream extremity. Upstream pulling cable is shortened in this way, and thus said other extremity approaches the upstream extremity.

Furthermore, according to another particularly advantageous embodiment of the invention, said one of said opposite extremities is connected to said downstream extremity by means of a downstream pulling cable to be able to draw said one of said opposite extremities towards said downstream extremity. In the same way as for the other extremity, said one of said opposite extremities is here easily drawn towards the downstream extremity as a resuit of the downstream pulling cable so that they can be then connected.

- 9 According to a variant embodiment the pulling cables may be pulled from the surface, using a return pulley fitted instead of the winches, as will be explained below.

Other features and advantages of the invention will be apparent from a reading of the description of a particular embodiment of the invention provided below by way of a non-limiting indication with reference to the appended drawings in which:

- Figure 1 is a diagrammatical view illustrating the context of the invention in general according to a first embodiment;

- Figure 2	is	a diagrammatical	detailed	view of
Figure 1 showing	the	object of the invention in	a first
situation;
- Figure 3	is	a diagrammatical	detailed	view of

Figure 1 showing the object of the invention in a second situation;

Figure 4 is a diagrammatical view showing a method of connecting an underwater flow line and an underwater riser during a first stage of approach;

- Figure 5 is a diagrammatical detailed view of Figure 4, illustrating a second stage of approach;

- Figure 6 is a diagrammatical detailed view of Figure 4, illustrating a third stage of approach;

- Figure 7 is a diagrammatical view illustrating the coupling device resulting from use of the method illustrated in Figures 4 to 6; and,

- Figure 8 is a diagrammatical view showing the coupling device resulting from use of the method illustrated in Figures 4 to 6 in a variant embodiment.

Figure 1 diagrammatically illustrâtes a depth of water, for example 1500 m, between a seabed 10 and a surface 12. A seabed underwater pipe 14, or flow line in English, runs over seabed 10. It reaches an anchoring area 16 and may directly départ from an underwater facility which is not shown, or from a well capable of delivering a hydrocarbon. From anchoring

- 10 area 16 and in the direction of surface 12 an underwater riser 18 extends substantially vertically up to a subsurface zone 20 located below surface 12, in which it is held by a float 22. At the opposite end the riser is held on seabed 10 by means of a foundation 25.

Immediately above and on surface 12 there floats a surface vessel 24 connected to underwater riser 18 via a flexible pipe 26. In addition to this, at the level of seabed 10 underwater riser 18 and underwater flow 10 line 14 are connected together by means of a déformable coupling device 28 which will be detailed below. As a resuit of this the fluid flowing within underwater flow line 14 can be delivered to surface vessel 24 through the intermediary of underwater riser 18 and flexible 15 pipe 26. In this case it is a hydrocarbon which is intended to be lifted to the surface. However in some circumstances it is necessary to deliver pressurized gas or water in the opposite direction, from the surface to the seabed.

Underwater riser 18 has an upstream extremity 30, while underwater flow line 14 has a downstream extremity 32.

Reference will now be made to Figure 2, which shows anchoring area 16 in greater detail. Here again 25 there is seabed 10 and underwater flow line 14, the downstream extremity 32 of which is of one piece with a trolley 34 resting on seabed 10. Trolley 34 may be an end terminal of the underwater flow line, or Flow Line End Termination (FLET) in English, a T-pipe connection, 30 or In-Line Tee (ILT) in English, an underwater isolation valve, or Subsea Security Isolation Valve (SSIV) in English, or any other equipment for undersea pipes known to those skilled in the art.

Trolley 34 is then capable of being drawn in 35 translation over. seabed 10 when underwater flow line 14 extends through the effect of the heat transmitted to it by the hot fluid carried, or, in an opposite

- 11 direction, when it retracts as a resuit of stoppage in the flow of said hot fluid.

Downstream extremity 32 is rigid, and W-shaped, so that it can end in a downstream end fitting 36 which is inclined at approximately 25° with respect to the vertical, and substantially above seabed 10 at a height that is for example substantially greater than 4 m.

According to other embodiments which are not shown, the downstream end may be inclined in relation to the horizontal at an angle of between +/- 90°. Also the rigid downstream extremity may be formed simply of an elbow.

In addition to this the downstream end may be raised to a height above the seabed of between 0.5 m and 100 m.

In the case of riser 18, this has an elbow-shaped upstream extremity 38 ending in an automatic connection coupling 40. Riser 18 extends according to a vertical component, while elbow-shaped upstream extremity 38 extends substantially horizontally. In addition to this riser 18 comprises guide means 41 that are substantially tapering and located around elbow-shaped upstream extremity 38. Their functions will be explained below.

According to a variant embodiment of the invention which is not shown, the upstream extremity of underwater riser 18 comprises a connection coupling orientated substantially vertically towards the seabed. According to a variant embodiment illustrated in Figures 4 to 7, which will be described in greater detail further on in the description, the connection coupling is orientated vertically away from the seabed, towards the surface.

Furthermore, riser 18 is extended by a lower anchoring extremity 42 held within a retaining cage 44 of one piece with a foundation 46 anchored into seabed

10. Lower anchoring extremity 42 is mounted so as to pivot in retaining cage 44. In this way riser 18 will pivot not only substantially around its lower anchoring extremity 42 driven by the movement of maritime currents, but will also be capable of being drawn in rotation about its own axis. In the latter case elbowshaped upstream extremity 38 tends to be drawn substantially in rotation in a horizontal plane.

Between automatic connection coupling 40 extending underwater riser 18 and downstream end fitting 36 extending underwater flow line 14 there is a distance of substantially less than for example 40 m, in a horizontal component. In addition to this downstream end fitting 36 is connected to automatic connection coupling 40 through a flexible pipe 48 extending in a bell-shaped curve, which will shortly be described structurally.

According to another embodiment there is a distance of the order of a kilometer between automatic connection coupling 40 and downstream end fitting 36 extending underwater flow line 14.

Flexible pipe 48 comprises a leaktight internai sheath made of polymer material, and a reinforcing wire wound in a spiral, forming touching turns, around the internai sheath. This is also wound in tight turns. The spiral reinforcing wire protects the inner leaktight sheath from the exterior, but above ail holds it when a pressurized hydrocarbon is flowing within it. In this way the reinforcing wire wound in a tight spiral can take up the radial forces exerted on the inner sheath.

In accordance with another embodiment a pair of reinforcing wires imbricated one within the other is wound in a tight spiral around the inner leaktight sheath.

Preferably, the reinforcing wire, or pair of reinforcing wires, wound in a spiral are themselves covered with an outer protective sheath to prevent the leaktight inner sheath from being subjected to hydrostatic pressure. Advantageously, and when flexile pipe 48 is likely to be subjected to longitudinal

- 13 tensile forces, at least one tensile reinforcing layer wound in open turns is mounted between the outer protective sheath and the touching turns of the reinforcing wire. Furthermore, according to one embodiment, and in the case where the leaktight inner sheath is likely to collapse upon itself, a métal carcass made of a métal strip interlocked into a spiral is used within.

Such a pipe 48 may for example hâve a weight of between 100 kg per meter and 2000 kg per meter, and the volume which it represents is between 30 L and 20 L per meter. Preferably, it will hâve a weight of between 350 and 450 kilograms per meter, for an internai volume of between 50 and 70 liters per meter.

Thus, because of its structure, flexible pipe 4 8 is capable of being curved to a minimum radius of curvature R_m, of for example between 5 m and 15 m, more specifically between 8 and 10 meters. According to one embodiment the length of the flexible pipe is between 2 π and 5/2 π times minimum radius of curvature R_m.

In addition to this, flexible pipe 48 is equipped with floats 50 formed from annular rings within which flexible pipe 48 runs. Floats 50 are regularly spaced from one another on flexible pipe 48 at distances of for example between 2 and 10 meters.

In accordance with one embodiment in which the flexible pipe has a length of the order of a kilometer, the floats may be spaced successively one after the other at distances of between 20 m and 100 m, for example.

Also, given the weight of flexible pipe 48, together with that of the fluid which it transports, the number and volume of floats 50 will be adjusted appropriately. To a first approximation a float having a volume of air of a cubic meter will be capable of supporting a weight which is substantially équivalent to 1000 kg.

- 14 As a resuit, and as shown in Figure 2, flexible pipe 48 has a length of close to 50 m.

According to said other variant embodiment flexible pipe 4 8 may hâve a length of between a few tens of meters and several kilometers. Flexible pipe 48 comprises a first extremity and a second extremity located opposite said first extremity. An automatic connection end fitting 52 may be fitted to the first extremity. The second extremity may be crimped in downstream end fitting 36.

Automatic connection end fitting 52 is elbowed to an angle of for example between 115° and 135°. Advantageously the angle of the elbow is close to 120° and as a resuit the first extremity of flexible pipe 48 is inclined at an angle of approximately 30° to the vertical, then automatic connection end fitting 52 is engaged in automatic connection coupling 40 substantially horizontally. It will be noted that automatic connection end fitting 52, or connector, is engaged in automatic connection coupling 40 by means of an underwater robot and during the last stage of the approach automatic connection end fitting 52 is guided laterally by means of guide members 41.

As shown in Figure 2, upstream elbow extremity 38 ending in automatic connection coupling 40 rises to a height of approximately 15 m in relation to seabed 10, flexible pipe 48 supported by floats 50 and shaped in the form of a bell curve having an apex close to 30 m from seabed 10.

The dimensions indicated here are not in any way limiting, and upstream elbow extremity 38 may for example be at a height of approximately 150 m above seabed 10, in which case the length of flexible pipe 48 will be increased as a conséquence, while the apex of the bell-shaped curve will be at a height of more than 150 m.

This being the case it will be understood that the déposition of sédiments on seabed 10, which generally

- 15 results in the burial of structures, cannot in such circumstances cover flexible pipe 48 quickly. It is in fact envisaqed that for an operating period of 20 years the risk of burial is virtually zéro.

Furthermore, thanks to flexible pipe 48 being shaped in the form of a bell, relative movement of underwater riser 18 and underwater flow line 14 can take place without any risk to the conduct of operations. In fact, considering for example that in Figure 2 hot fluid passes through pipes 14, 18 and flexible pipe 48, flow line 14 has an operating length greater than its resting length when fluid is not passing through it. This is simply due to the thermal energy provided by the fluid to underwater flow line

14.

Conversely, as soon as hot fluid ceases to pass through, underwater flow line 14 tends to cool and as a resuit shrink. As a conséquence, and as illustrated in Figure 2, trolley 34 drawn along seabed 10 by underwater flow line 14 moves away from foundation 4 6 and as a resuit flexible pipe 48 extends, while floats 50 approach seabed 10.

If the	amplitude	of	movement	of trolley 34	for
example of	the order	of	tens	of	meters, it will	be
understood	that because	of	its	construction	the
deformation	of flexible	pipe 48	can	be wholly withstood

without giving rise to any damage, in comparison with déformable coupling devices according to the prior art made of rigid U-shaped pipes.

In addition to this, rotational movement of underwater riser 18 about its own axis, which gives rise to substantial rotation of elbow-shaped upstream extremity 38 in a horizontal plane is wholly taken up by the deformation of flexible pipe 48. Advantageously, in order to avoid the latter from becoming excessively curved at its extremities, the latter are fitted with curvature-limiting sleeves, which are not shown here.

- 16 A method of connection according to the invention will now be described with reference to Figures 4 to 7. Eléments eguivalent to éléments illustrated in Figures to 3 will hâve the same reference number marked with an apostrophe: Other éléments will hâve a reference number in the sequence of reference numbers already used.

Thus Figure 4 shows an underwater riser 18' moored to a foundation 25' anchored on a seabed 10' and held vertically by a float 22' . An underwater flow line 14' runs over seabed 10' and ends in a downstream extremity 32' located close to said foundation 25' . As for underwater riser 18' , this has an upstream extremity

30' close to foundation

Furthermore, above seabed 10', a workboat 54 sails on surface 12'. In addition to this a déformable coupling device 28' opposite having two according ends 56, to

58, the is invention, and suspended from cables 60, 62.

of two suspension device 28' comprises a flexible pipe 48' fitted with floats 50' . The two suspension workboat 54

Déformable by means coupling cables 60, 62 are connected to the two opposite extremities 56,

Déformable respectively.

coupling device 28' is thus lowered towards seabed

10', above upstream extremity

30' and downstream extremity 32' respectively of underwater riser 18' and flow line 14', by paying out suspension cables 60, 62. In order to facilitate this approach underwater riser 18' is substantially moved away from its vertical position by drawing float 22' to the side

by means of a	tug, which is not illustrated, on surface
12' .
As	soon	as déformable coupling device	28'	is
sufficiently	close to upstream extremity	30'	and

downstream extremity 32' , according to a particularly advantageous embodiment, its two opposite extremities 56, 58 are respectively connected to upstream extremity 30' and downstream extremity 32' by means of a downstream cable 66.

downstream pulling cable 64 and an upstream pulling Downstream pulling cable 64 is engaged in a winch 68 at downstream extremity 32' , while upstream cable 66 is engaged in upstream winch 70 at upstream extremity 30' .

Reference will now be made to Figures 5 and 6, detailing the method of connection. Underwater flow line 14' and underwater riser 18 are shown in detail in

Figure 5, illustrating and their upstream Downstream extremity 32' end fitting 36' orientated away extremity 38', it a connecting coupling away from seabed 10' . pulling cable 64 has been of extremities which from has a their downstream extremity 38' is extended by is substantially seabed 10'. As extremity 32' respectively.

a downstream vertical and for upstream as

U-shaped elbow so also orientated

40'

In winch 68 and one coupling device end fitting 36' therein. It will

28' in be this Figure 5 wound up using of to présent vertically downstream downstream déformable has been order to noted that drawn towards downstream cable 60 has been released

Then upstream winch cable 66 upstream pulling of déformable member 40' as by and be subsequently engaged corresponding suspension the same amount.

coupling illustrated device is operated to wind up thus draw other extremity towards connecting Figure 6. Also is released in

28' in corresponding suspension cable parallel. Flexible pipe device 28' thus tends to form a bell-shaped seabed 10' between upstream extremity downstream extremity 32'.

Automatic connection end

48' of déformable coupling above curve

30' and fitting to each

52' and connection coupling 40' are close are not necessarily orientated in

Thus a heavy weight 72 is provided to disadvantage and assist further said heavy weight 72 is adjusted on said flexible pipe 48' at a particular distance from or even coaxial.

overcome this connection, and other, but the same direction,

- 18 automatic connection end fitting 52' in such a way that said flexible pipe 48' can be arched and automatic connection end fitting 52' can be reorientated. The mass of heavy weight 72 is likewise determined so that this orientation can be achieved perfectly. It may for example vary between 100 kg and 1000 kg.

Heavy weight 72 is for example fitted onto flexible pipe 48' before it is immersed, or directly in situ using an underwater robot, which is not shown.

Thus, through the underwater robot, automatic connection end fitting 52' is connected to connection coupling 40' to make the connection.

Figure 7 thus shows déformable coupling device 28' and flexible pipe 48' in a bell-shaped arrangement above seabed 10' connecting upstream extremity 30' of underwater riser 18' and downstream extremity 32' of underwater flow line 14'.

In another variant embodiment illustrated in Figure 8, where éléments équivalent to the éléments illustrated in Figure 7 hâve the same reference number marked by a double apostrophe, ” , downstream end fitting 36 extends underwater flow line 14 substantially parallel on seabed 10, and not vertically. Flexible pipe 48 of déformable coupling device 28 then forms a double curve, with a first concave part and a second convex part.

Claims (2)

1. A déformable coupling device intended to connect an underwater flow line (14) running on a seabed (10) along a horizontal component to carry a fluid and an underwater riser (18) running from said seabed along a vertical component towards a sea surface (12) to be able to carry said fluid between said seabed and said sea surface (12), said coupling device having two opposite extremities, while said underwater flow line (14) has a downstream extremity (32) and said underwater riser (18) has an upstream extremity (38), the said opposite extremities being intended to be connected to said upstream and downstream extremities respectively;

characterized in that it comprises a leaktight sheath of polymer material and at least one reinforcing wire wound in a hélix around said leaktight sheath to form a flexible pipe (48), and in that it comprises at least one float (50) connected to said flexible pipe (48) so as to shape said flexible pipe into a bellshaped curve with respect to said seabed (10) between said upstream extremity (38) and downstream extremity (32) .

2. The coupling device according to claim 1, characterized in that it comprises a plurality of annular floats (50) fitted close to each other around said flexible pipe (48).

3. The coupling device according to claim 1 or 2, characterized in that said underwater riser (18) has guide members (41) around said upstream extremity (38), a first extremity of said opposite extremities of said flexible pipe (48) is fitted with a connector (52) intended to be guided towards said upstream extremity (38) by said guide means (41).

4. The coupling device according to claim 3, characterized in that said upstream extremity (38) of said underwater riser (18) comprises a connection member orientated in a direction between a horizontal direction and a vertical direction away from said seabed (10).

5. The coupling device according to claim 4, characterized in that said upstream extremity (38) of said underwater riser (18) comprises a connection member (40) orientated substantially horizontally.

6. The coupling device according to claim 4, characterized in that said upstream extremity (38) of said underwater riser (18) comprises a connection member orientated substantially vertically.

7. The coupling device according to any one of claims 1 to 6, characterized in that said first extremity of said opposite extremities of said flexible pipe (48) comprises a connector (52) having an elbow.

8. The coupling device according to any one of claims 1 to 7, characterized in that it further comprises curvature-limiting sleeves mounted around said flexible pipe (48) in the vicinity of said opposite extremities.

9. The coupling device according to any one of claims 1 to 8, characterized in that said flexible pipe (48) has a minimum radius of curvature MBR and a length L, and in that said length L is between 2 π and 5/2 π times said minimum radius of curvature MBR.

10. The coupling device according to any one of claims 1 to 9, characterized in that said at least one reinforcing wire is wound in a hélix so as to form touching turns about said leaktight sheath.

11. The coupling device according to any one of claims 1 to 10, characterized in that it further comprises an outer protection sheath extending around said at least one reinforcing wire wound into a hélix.

12. The coupling device according to any one of claims 1 to 11, characterized in that it comprises an automatic connection member (40) intended to be mounted on said upstream extremity (38) and an automatic connection end fitting (52) installed on said first fa extremity of said opposite extremities, said automatic connection end fitting (52) being intended to be engaged in said automatic connection member (40).

13. The coupling device according to any one of claims 1 to 12, characterized in that said downstream extremity (32) of said underwater flow line (14) has a downstream end (36) orientated substantially vertically.

14. A method for connecting an underwater flow line (40) running according to a horizontal component on the seabed (10) to carry a fluid and an underwater riser (18) running from said seabed along a vertical component to a sea surface (12) to be able to carry said fluid between said seabed and said sea surface (12), said underwater flow line (14) having a downstream extremity (32) and said underwater riser (18) having an upstream extremity (38), the method being of the type comprising the following stages:

1) a coupling device having two opposing extremities is provided;

2) the said opposing extremities are connected to said upstream and downstream extremities respectively;

characterized in that in stage 1) a coupling device comprising a leaktight sheath of polymer material and at least one reinforcing wire wound in a hélix around said leaktight sheath to form a flexible pipe (48) and at least one float (50) connected to said flexible pipe (48) is provided, and in that in stage 2) said opposite extremities are connected to said upstream and downstream extremities respectively so as to shape said flexible pipe into a bell-shaped curve in relation to said seabed (10) between said upstream extremity (38) and downstream extremity (32).

15. The method of connection according to claim 14, characterized in that in stage (2) one of said opposite extremities is connected to said downstream extremity (32) of said underwater flow line (14) and in that the opposite extremities and said upstream extremity (38) are connected by means of an upstream pulling cable so that said one of the said opposite extremities can be pulled towards said upstream 5 extremity (38) .

16. The method of connection according to claim

15, characterized in that in stage 2) said one of the said opposite extremities is connected to said downstream extremity (32) by means of a downstream 10 pulling cable in order to be able to pull said one of the said opposite extremities towards said downstream extremity (32).