OA16505A - Flexible submarine line curvature limiter and bottom-to-surface connection installation including. - Google Patents

Abstract

The present invention relates to a curvature limiting device constituted by the fixing, end to end, of tubular sleeves (5), equipped on the upper face at their longitudinal ends with fixing and articulation devices (6) and lower stops (7i, 72 ), diametrically opposed on the lower faces. The present invention also relates to a bottom-to-surface connection installation between a subsea equipment, such as a subsea wellhead or the end of a subsea pipe resting on the seabed (16), and a floating support on the surface (12), comprising a flexible submarine line (2) whose curvature is controlled by a said curvature limiting device (1) according to the invention, said curvature limiting device being disposed at an intermediate depth between the bottom sea (16) and surface (17).

Description

SUBMARINE FLEXIBLE LINE CURVATURE LIMITER AND

BOTTOM-SURFACE CONNECTION INSTALLATION INCLUDING

The present invention relates to a curvature limiting device forming a tubular member capable of adopting a rectilinear position or a variable curvature by preventing a radius of curvature less than a given minimum radius of curvature Ro and thus allowing a controlled variable curvature or the absence of curvature of a flexible line threaded inside said tubular member.

The present invention also relates to a bottom-to-surface connection installation between (a) underwater equipment, such as an underwater wellhead or the end of an underwater pipe resting on the seabed and (b) a surface floating support, comprising a flexible submarine line, the curvature of which is locally controlled by a curvature limiter.

More particularly, the present invention relates to an installation comprising a hybrid tower consisting of a flexible pipe connected to a rigid riser pipe or vertical riser, the lower end of which is connected to the upper end of said equipment or one said end. underwater pipe resting at the bottom of the sea, said tower being coupled to at least one said flexible line passing through a curvature limiter attached to said riser and / or in suspension attached to a float in the subsurface.

The term flexible submarine line is understood here to mean a line that is easy to bend to obtain a minimum radius of curvature of a few meters, in particular from 0.5 to 5 m while remaining in the elastic range, as opposed to a rigid steel pipe whose wall is massive and whose radius of curvature in the elastic range is several tens or even hundreds of meters. Such flexible lines are for example

a) a flexible petroleum fluid transfer pipe such as those manufactured by the company COFLEXIP (France) used in particular in the hybrid towers mentioned above, and conventionally made of an internal tube of flexible polymer material reinforced by wire reinforcements metallic or braided composites, forming spiral sheaths, and where appropriate a plurality of intermediate or outer tubes between said reinforcements,

b) cables or conduits for energy or information transfer such as electric cables, control cables or hydraulic fluid transfer conduits supplying hydraulic equipment such as jacks or conduits containing optical fibers, or again

c) umbilicals, that is to say conduits comprising a plurality of such electric cables, hydraulic conduits, control cables and / or optical fibers.

The technical sector of the invention is more particularly the field of the manufacture and installation of production risers for the underwater extraction of oil, gas or other soluble or fusible material or of water. a suspension of mineral matter from a submerged wellhead to a floating support, for the development of production fields installed in the open sea off the coast. The main and immediate application of the invention being in the field of oil production.

The floating support generally includes anchoring means to remain in position despite the effects of currents, winds and swells. It also generally comprises means for storing and processing the oil as well as means for unloading to stripping tankers, the latter appearing at regular intervals to carry out removal of the production. The common name of these floating media is the Anglo-Saxon term Floating Production Storage Offloading (meaning floating storage medium, decx /

t production and unloading), the abbreviated term FPSO of which is used throughout the following description.

Bottom-to-surface connections are known of an underwater pipe resting on the seabed, a tower-hybrid type connection comprising:

- a substantially vertical steel riser, the lower end of which is anchored to the seabed and connected to a said pipe resting on the seabed, and

a connecting pipe, in general a flexible connecting pipe, in continuity of curvature in a plunging chain, between the upper end of said riser and a support floating on the surface, said flexible connecting pipe possibly comprising, over part of its length, buoyancy elements. The term “plunging chain” is understood here to mean a curvature in geometric shape called a chain with a low point of inflection.

This type of bond is more particularly described in patent WO-2009-138609. In patent WO-OO / 49267 of the applicant, a variant of a hybrid tower is described comprising a plurality of vertical rigid pipes joined together at various levels.

Complementary bottom-surface flexible connections of the electric cable or electro-hydraulic umbilical type are added after installation of the hybrid tower, said complementary bottom-surface connections being generally continuous from the FPSO, to their destination, that is to say for example an underwater wellhead located several kilometers away from said FPSO.

It is recalled in this regard, that the essential function of these portions of plunging chains of flexible lines is to absorb, at least in part, the movements of the rigid pipes to which said line is fixed or hooked and / or the movements of the floating supports to which said flexible line is connected, by mechanically decoupling the respective movements of said rigid pipes and said floating supports. But another function is also to reduce ^

ΐ the tensile forces exerted by the flexible line on the underwater equipment at the bottom of the sea to which it is connected, if applicable.

In FR 09 58096 in the name of the applicant, filed on November 17, 2009, bottom-surface installations are known, in which a plurality of flexible lines comprises line portions in the form of a plunging chain curve, obtained by hanging from a buoy. a portion of said flexible line at an intermediate height between the bottom and the surface. To do this, said intermediate portion of flexible line or pipe is passed through a chute defining a rigid bearing surface of convex curved shape.

Such a chute makes it possible to give the portion of flexible pipe which it supports a controlled curvature to avoid excessive curvature which would irreparably degrade said pipe. However, the installation of these chutes on the one hand and flexible pipes over these chutes on the other hand requires complicated and long and therefore expensive maneuvers.

In FR 2 889 557, it is proposed to implement a curvature limiting device, consisting of a tubular member in which the pipe is threaded, which can be preinstalled around the pipe either in the factory or at aboard a laying vessel. The curvature limiting device is fitted with the pipe threaded into said curvature limiting device, the latter then having a rectilinear shape, the external diameter dimensions of which are compatible with the dimensions of the pipe passage hatches at the level of the laying vessel. , in particular at the base of the laying towers in J, with the help of which one unwinds and deposits the pipes at sea from the laying vessel. Thus, it is then sufficient to suspend or hang the curvature limiter at an intermediate height between the bottom and the surface, then to give it a curved shape with a convex shape facing upwards, so as to create on at least one on its side a portion of flexible pipe or line in the form of chains ^ / plunging. This flexible tubular member constituting said curvature limiter described in FR 2 889 557, comprises a plurality of tubular sleeves arranged end to end in an axial longitudinal direction and loosely connected to each other by annular members. Said sleeves and said annular members have non-cylindrical longitudinal ends which fit into each other without being fixed to each other. More specifically, the sleeves have at each end flanges curved radially outwards forming a shoulder while the annular members have at each of their ends a radial inward curving forming shoulders in the opposite direction capable of cooperating in interlocking with the shoulders at the ends of said sleeves.

The sleeves and annular members thus nested one inside the other successively constitute an articulated assembly allowing movements between the various elements, both in the axial longitudinal directions of the sleeves and in the lateral directions perpendicular to the said axial longitudinal directions. And, this clearance allows a curvature of the tubular member, said curvature being limited by the maximum clearance allowed on an upper face of said sleeves and annular members, when their lower face has minimum clearance.

This type of curvature limiter therefore allows a variable curvature of the flexible line or pipe, including a rectilinear position, by preventing the curvature of said flexible line below a determined minimum radius of curvature.

Such curvature devices of the nested vertebrae type as described in patents FR 2 889 557 and US 2010/0228295 have been known for a long time and were developed and used for the first time at the Chevron-Ninian en Mer site. of the North in 1978.

GB 2 334 048 also describes a curvature restrictor for ^> 7

»Flexible pipe of the type with interlocking and alternating half vertebrae.

This type of curvature limiter has certain drawbacks. First of all, they are delicate and expensive to manufacture, since they require the implementation of an interlocking of parts manufactured on a lathe with relatively high precision, and therefore parts which are relatively expensive to manufacture. Likewise, the assembly of the various sleeves and annular members is relatively delicate and complex to achieve.

On the other hand, this curvature limiting device does not provide a stable and precise curvature, because its stability is only linked to its own weight. In addition, this curvature limiting device can be deformed, in particular if one pulls laterally in a direction perpendicular to the mean plane of curvature due to the fact that the various unit elements fitted into each other are independent of each other and may experience deflections. side by side with respect to each other, which constitutes a drawback, in particular when it is desired to implement a plurality of flexible lines and therefore a plurality of side-by-side curvature limiters nearby, in particular arranged on the two opposite faces of 'a float or a rigid pipe as described in FR 09 58096.

Another drawback of the curvature limiter device described in FR 2 889 557 is that it induces a limitation of the curvature of the flexible line in all directions, which can in certain cases hinder, or even prohibit, winding. of the flexible line equipped with said curvature limiter device around a storage reel on board a laying vessel.

Another drawback of the curvature limiter device described in FR 2 889 557 is that the pipe is clamped inside the sleeves to maintain a fixed relative position of the curvature limiter with respect to the pipe, which requires installing said pipe. device for limiting the curvature around a single pipe element only after having scrolled and laid a portion of pipe of /// "

corresponding length as a function of the height at which said curvature limiting device must be hung or suspended between the bottom and the surface.

The aim of the present invention is therefore to provide a new type of curvature limiter device that is simpler to produce, more reliable in terms of precision and stability of the desired curved shape, in particular without lateral movement allowed between the various components of the device. when implemented in a controlled curvature configuration.

Another object of the present invention is to provide a novel curvature limiter device which further offers the possibility of being implemented in a configuration providing control of the curvature by limiting the curvature, but also a configuration in which the device has no curvature limiting effect, said flexible line fitted with said curvature limiter then being able to be bent beyond the maximum curvature limit authorized in the previous configuration.

More generally, the aim of the present invention is to provide an improved curvature limiting device that is simpler to produce but also simpler to implement, in particular as regards its attachment to an intermediate position between the bottom and the surface.

To do this, the present invention provides a curvature limiting device forming a tubular member capable of adopting a rectilinear position or a variable curvature by prohibiting a radius of curvature less than a given minimum radius of curvature and thus allowing a controlled variable curvature or l 'absence of curvature of a flexible line threaded inside said tubular member, said tubular member comprising a plurality of tubular sleeves arranged end to end at their longitudinal ends, preferably at least 3 sleeves, more preferably from 3 to 9 sleeves, characterized in that said sleeves are fixed to each other by fixing devices and (flJ *

rotating articulation arranged on the upper face of each of said sleeves, at their longitudinal ends, said fixing devices and rotating articulation allowing rotation of the longitudinal axis XX ', XjXi' of a first sleeve with respect to the 'longitudinal axis XX', X2X2 'of a second sleeve fixed to said first sleeve by means of said fixing and articulation device, said rotation being around an axis of rotation YY', YjYi ', Y2Y2' perpendicular to the two said longitudinal axes XX ', ΧιΧ /, X2X2' of said first and second sleeves, preferably the two axes of rotation YjYi ', Y2Y2' of the two fixing and articulation devices arranged at the two opposite longitudinal ends of each sleeve being arranged at a same distance L ₂ from the longitudinal axis XX ', X1X1', X ₂ X2 'of said sleeve, said sleeves further comprising at their two longitudinal ends respectively two stops of complementary shape silent, arranged against the lower faces of said sleeves in positions substantially diametrically opposed relative to said fixing and articulation devices, the two end end faces of the two stops at the longitudinal ends facing said first and second sleeves being spaced one from the other when said tubular member is in a rectilinear position, and having a common contact surface when the two said stops are in contact with each other by the maximum authorized rotation of the two lower faces of the two said sleeves towards each other by virtue of said fixing and articulation devices.

We understand that:

- Said fixing and articulation device is such that the downward pivoting of the two sleeves by bringing their lower faces together is limited by the contact between their two stops, while, on the other hand, the pivoting towards the top of the two sleeves by bringing their upper faces together would be limited, if necessary, only by the contact of the longitudinal ends of their upper faces, if the latter were not themselves fixed to another juxtaposed sleeve; etpj

- Said stops have the function of stabilizing and making more reliable in terms of mechanical strength over time and under stress the curved position of the curvature limiter device in said maximum authorized rotation;

- the maximum authorized inclination a between the two longitudinal axes ΧιΧ /, X2X2 'of the two successive sleeves by bringing their lower faces together depends on the distance L ₃ between said respective stops facing each other when said tubular member is in position rectilinear; and

- the fixing to each other of the sleeves arranged end to end by said fixing and articulation devices does not allow any longitudinal or lateral movement of the various sleeves with respect to each other, except for the natural play of the mechanical parts fixed to each other as will be explained below.

It is understood that said sleeves comprise at each of their two longitudinal ends a said fixing and articulation device, except as regards the longitudinal ends of the two terminal sleeves corresponding to the two longitudinal ends of said tubular member.

The curvature-limiting device thus defined is advantageous in that it enables a said curvature to be produced more precisely and stably.

Another advantage of the curvature-limiting device according to the present invention lies in that it can be curved, with a curvature limitation, by bringing the lower faces of the sleeve together, as described above, but also allow a reverse curvature by approximation. of the upper faces of the sleeves and without limitation of curvature or with a smaller radius of curvature. This possibility of reverse curvature is more particularly advantageous in that it allows, on the one hand, the implementation of a flexible line equipped with said curvature limiter wound on a storage reel, /// in particular on board. a laying vessel, and, on the other hand, facilitates the laying at sea of a said flexible line equipped with said curvature limiter and the attachment of said curvature limiter to a buoy or rigid vertical submarine pipe, to an intermediate height between the bottom and the surface, as will be explained below.

Another advantage of the device according to the invention lies in that it can be manufactured more simply, in particular by mechanical welding of said fixing and articulation devices and of said stops against the upper and lower faces of said sleeves, respectively.

It is understood that when the axes of rotation YY ', ΥιΥ /, Y2Y2' of the two fixing and articulation devices arranged on the upper faces of the two opposite longitudinal ends of each sleeve are spaced from each other by the same length L] for all sleeves of which the axes of rotation YY ', YiY /, Y ₂ Y ₂ ' of said fixing and articulation devices are at the same distance L _{2 from} said longitudinal axes XX *, X1X1 ', X ₂ X ₂ ' of the respective sleeves, said maximum rotation angles a resulting from the contact of the two said abutments of the lower faces two by two, are all identical, and said curvature limiting device allows a minimum circular radius of curvature R _o of said flexible line inside of the curvature limiter, such as:

"O = x dimension (f) -t ₂

More preferably, the different sleeves are all of the same shape, the same length and the same internal and external diameters.

In practice, said maximum authorized angle of rotation a by bringing the lower faces of the two sleeves attached to each other together by means of said fixing device and articulation is from 5 to 45 °, preferably η xa being at least 60 °, preferably from 60 to 150 ° when said tubular member comprises n said fixing and articulation devices with n preferably being an integer from 3 to 21 of ίλ / more preferably from 5 to 15 and L1 = 15cm to 1m, L2 = 5cm to 50cm and R _o = 0.5m to 5m.

For reasons of ease of manufacture and machining, in a particular embodiment, said contact surface of said stops comprises at least one plane.

In a preferred embodiment, said front faces of two abutments comprise three-dimensional surfaces of complementary shapes, concave and convex respectively, so that said contact surface has a three-dimensional shape preventing any lateral movement of the two said first and second sleeves, the 'one relative to the other, in a direction perpendicular to one of said longitudinal axes ΧιΧι', X2X2 'of said first and second sleeves, and having an effect of centering the longitudinal axes XiX', X ₂ X 'of said first and second sleeves substantially along the same axial radial longitudinal plan P _o when the two said stops come into contact with each other.

This embodiment is particularly advantageous because it makes it possible to implement fixing and articulation devices, allowing a certain play in a lateral direction, in the direction of said axis of rotation YY '. This therefore makes it possible to avoid the use of precision mechanics to achieve the cooperation in rotation of the different parts at the level of the fixing and articulation device. This recentering also makes it possible to avoid deformations and / or wear of said fixing and articulation devices. Finally, this recentering makes it possible to guarantee greater stability of the shape of the curvature limiting device, in particular with regard to any lateral deflections. The flexible pipe is then in safety, in the same way as on a chute in mechanically-welded structure of the prior art.

In a first embodiment, the lower stop at one end of the first sleeve has a convex or concave C / J shape complementary to the concave or respectively convex shape of the stop opposite at the end of the second sleeve, each sleeve therefore having two stops of different shapes convex and concave respectively at its two longitudinal ends.

In a second embodiment, a first sleeve comprises two stops of the same convex or concave shape at each of its two longitudinal ends, said first sleeve being fixed at each end to a second sleeve, having stops of the same concave or respectively convex shape. .

More particularly, said contact surface is formed of two planes arranged in a dihedral, having a common edge, said edge being preferably arranged in alignment with a straight line D _o in intersection with said axis of rotation YY ', YiYf, Y2Y2' of said fixing device and corresponding articulation. It is understood that said edges of the two stops are thus found substantially in the same said longitudinal axial plane P _o , when said stops come into contact with one another, and all of the elements of the device are locked substantially in one. same longitudinal axial plane P _o .

Again advantageously, the two said stops at said longitudinal ends facing two said first and second sleeves fixed to one another, comprise locking elements, capable of retaining said stops locked against one another. 'other as soon as they come into contact with each other at a said contact surface in the event of said maximum rotation a.

More particularly, a first stopper at the end of a first sleeve comprises a hook, articulated in rotation on said first stopper and a second stopper at the end of the second sleeve opposite the first stopper, comprises a shape, capable of being hooked by said hook when the two stops come into contact with one another at the level of a said contact surface, an elastic return element cooperating with said hook maintaining the two stops in said contact in preventing the separation of the two stops from one another once they have come into said contact.

More particularly still, said device for fixing and articulation of two first and second sleeves comprises:

- a first fixing and articulation element comprising at least a first part defining at least a first planar face disposed along a said radial plane P _o on the upper face of said first sleeve at its longitudinal end facing said second sleeve, said first part comprising a circular orifice at said first flat face, said orifice passing transversely through at least said first part in a direction of said axis of rotation YY ', YiYf, Y2Y2' perpendicular to said axial longitudinal directions XX ', ΧιΧ /, X2X2 'of the two first and second sleeves, and

- a second fixing and articulation element comprising at least a second part defining at least a second flat face disposed along a said radial plane P _o on the upper face of said second sleeve at its longitudinal end facing said first sleeve, said second part comprising a circular orifice at said second plane face, said orifice passing transversely through at least said second part in the direction of said axis of rotation YY ', YjY /, Y2Y2' perpendicular to said axial longitudinal directions XX ', ΧιΧ /, X ₂ X ₂ 'of the two first and second sleeves, and

- A pin crossing transversely at least said first and second parts at their said orifices.

We understand that:

- Said first and second faces are arranged facing each other, where appropriate, substantially against each other and said fixing and articulation elements are articulated in rotation by £ K / relative to said pin, that -ci thus forming a part of axis of rotation, and

- The curvature limiting device according to the present invention is therefore constituted by the end-to-end fixing of common unit elements each comprising a said tubular sleeve equipped at its two longitudinal ends, with:

~ on its upper face, a said first fixing and articulation element at one end and a said second fixing and articulation element at the other end, and

- Against its lower face, said stops positioned substantially diametrically opposed to said first and second fixing and articulation elements, and

- The fixing between said first fixing and articulation element of a first sleeve with said second fixing and articulation element of a second sleeve is effected by means of said pin arranged through said openings of said first and second fixing and articulation elements.

The expression “upper face” and “lower face” of said sleeve is understood here to mean the upper outer and lower outer surfaces, in particular cylindrical of said sleeve.

Indeed, more particularly, said sleeve comprises a cylindrical outer surface, in particular with a circular cross section, defining an external diameter, as well as a cylindrical central passage, also with a circular section, defining an internal diameter.

It is also understood that said tubular member comprises two terminal unit elements each comprising a said sleeve equipped with a said single first and respectively second fixing and articulation elements at a single longitudinal end of said terminal element. ^

Again advantageously, in the fixing and articulation device according to the invention:

- Said first fixing and articulation element comprises at least one said first perforated part respectively defining two plane faces, parallel, facing each other, including a said first face, said two flat faces delimiting an empty space and being arranged at one distance from each other, and

- Said second fixing and articulation element comprises at least one second flat part comprising two parallel opposite flat faces including at least one said second face, said second flat part of a first sleeve being fixed to and interposed between the two said flat faces in vis-à-vis said first fixing and articulation element of a second sleeve, such that the orifices of the two opposite flat faces of said second flat part are arranged opposite the orifices respectively of the two flat faces of said first attachment and articulation element.

It will be understood that the two opposite flat faces of said second flat part are arranged at a distance from one another defining the thickness of said second flat part, this thickness being less than the distance d between the two flat faces of said first fixing and articulation element so that said second part can be inserted between the two said parallel flat faces of said first fixing and articulation element.

This embodiment is particularly advantageous in that the insertion of a said second flat part between the two said flat faces of a said first part provides lateral guidance, preventing any lateral movement of said first and second sleeves one by one. with respect to the other, in particular, by considerably limiting the play of movement of said second part relative to said first part in said direction of the axis of rotation YY '. £> 7

In a preferred embodiment, said fixing and articulation device comprises:

a said first fixing and articulation element at the end of a said first sleeve comprising two said first perforated flat pieces each comprising two opposite parallel flat faces, the two first flat pieces being arranged parallel side by side at a said distance d each other, and

a said second element for fixing and articulation at the longitudinal end of a said second sleeve comprising two said second perforated flat parts each comprising two parallel opposite flat faces, the two second flat parts being arranged parallel side by side at a said distance from each other,

a said first flat part of said first sleeve being interposed between the two said second flat parts of the second sleeve, and a said second flat part of the second sleeve being interposed between the two said first flat parts of the first sleeve, and

a same said pin being arranged through the orifices of the two said first flat pieces of the first sleeve and two said second flat pieces of the second sleeve thus interposed.

This embodiment is particularly advantageous, because the shear stresses in the axial direction XX 'at said pin are taken up at a greater number of shear planes, namely in this case three shear planes p ' _lf p * ₂ , p' ₃ (cf. FIG. 12B), between three flat faces of the two said first parts facing three flat faces of the two said second parts.

In addition, the insertion of a said first flat piece between two said second flat pieces on the one hand, and on the other hand of a said second flat piece between two said first flat pieces, improves the lateral guidance preventing any lateral movement of said first and second sleeves, with respect to one another, in particular by reducing the play of movements of said first parts with respect to said second parts in the direction of the rotation rate YY '.

According to another preferred characteristic of the present invention, the curvature limiting device comprises a locking device making it possible to block a said flexible line inside said curvature limiting device, thus preventing their relative lateral and / or longitudinal movement, the diameter internal of said sleeve being greater than the external diameter of said flexible line.

By lateral relative movement is meant here a movement in a direction perpendicular to said axial longitudinal direction of said sleeve.

More particularly, said locking device comprises at least one strap, preferably at least two straps, each strap passing through two orifices at the periphery of a sleeve, preferably a central sleeve of said tubular member, the two orifices being arranged at proximity to each other and positioned at the same level in the axial longitudinal direction XX 'of said sleeve, each strap encircling, partially at least, said flexible line inside said sleeve and exiting at its two ends by respectively the two orifices.

It is understood that, where appropriate, the second strap and a second pair of orifices are arranged at a different position, in the axial longitudinal direction XX 'of said sleeve, relative to the first strap and the first pair of orifices of the sleeve. .

Advantageously, each said tubular sleeve is composed of two half-sleeves with semicircular sections fixed to one another. It is understood that in this case said tubular sleeve obtained comprises a central longitudinal cylindrical orifice with a circular cross section C.sub.X / and that each half-sleeve has in cross section a semi-circular internal contour.

This feature is advantageous because it allows (installation of the curvature limiter on the flexible pipe completely completed, that is to say already having its end connectors. Indeed, the end connectors would be too bulky to pass. inside the tubular sleeves of the bend limiter.

According to another advantageous characteristic, the curvature limiting device according to the invention comprises at one longitudinal end on its underside a winch and a cable wound at one end around said winch, the other end of the cable being attached to an element of hooking arranged at the other longitudinal end of said tubular member on its underside, making it possible to tension said cable by actuating said winch and winding said cable around said winch and, thus, thus bringing the two longitudinal ends of said tubular member together to create a said curvature.

This characteristic is particularly advantageous, in particular when the pipe is insufficiently flexible for the curvature limiter to be able to adopt its position of maximum curvature by virtue of the simple self-weight of the flexible pipe in chain configuration, as explained below.

The present invention also provides a bottom-to-surface connection installation between a subsea equipment, such as a subsea wellhead or the end of a subsea pipe resting on the seabed, and a support. floating on the surface, comprising a flexible submarine line whose curvature is controlled by a said curvature limiting device according to the invention, said flexible line being threaded inside said tubular member and said curvature limiting device being arranged at a intermediate depth between the seabed and the surface.

Λ

More particularly, said bottom-surface connection comprises a hybrid tower consisting of a flexible pipe extending from a said floating support to the upper end of a rigid riser pipe or vertical riser, the lower end of which is connected to an item of equipment or one end of an underwater pipe resting on the seabed, said installation further comprising at least one curvature limiting device attached to said riser, preferably comprising at least two curvature limiting devices attached to a same height against two diametrically opposed faces of said riser.

The present invention also provides a method of laying a submarine line between a support floating on the surface and the seabed of a bottom-to-surface connection installation according to the invention, from a surface laying vessel, the curvature of said flexible submarine line being controlled by a said curvature limiting device according to the invention, arranged at an intermediate depth between the seabed and the surface, comprising the following successive steps in which:

- 1 / said curvature limiting device is arranged in a rectilinear position on the deck of a laying vessel, and said flexible line is unwound from a spool on the ship's deck by passing the flexible line through said curvature limiting device in a fixed position on the ship's deck, and

- 2 / the end of said flexible line is hooked to a said support floating on the surface, and

- 3 / one continues to unwind said flexible line through said curvature limiter, while moving the laying vessel away from said floating support, so that said flexible line adopts the form of a plunging chain, and

- 4 / when a given length L _o of flexible pipe has been unwound by passing through said curvature limiting device in C ^ / "" rectilinear position, said curvature limiting device is locked on said flexible line using a locking device, and said curvature limiting device is then being driven with said flexible line being removed, the curvature limiting device being in an inverted curvature configuration with a low curvature with concavity facing upwards, and

- 5 / the curvature limiter device is approached to a vertical rigid pipe or it is suspended from a float in the subsurface and the unwinding of said flexible line is continued so that the curvature limiter adopts a said maximum curvature R _o with its concavity turned downwards, said curvature limiter thus delimiting two portions of flexible line in the form of a plunging chain between on the one hand said floating support and said curvature limiting device and, on the other hand, said curvature limiting device and said vessel laying, and

- 6 / the removal of said flexible line is continued until the low point of horizontal tangency i of the plunging chain of the second portion of flexible line between said curvature limiting device and the surface laying vessel reaches the bottom from the sea and the laying of said flexible line on the seabed is then continued, always moving the laying vessel further away from the floating support while unwinding said flexible line from the spool onto the deck of the laying vessel.

This deposition method is made possible by the property of the curvature limiting device according to the invention of adopting an inverted curvature, as explained previously.

Other characteristics and advantages of the present invention will emerge better in the light of the detailed description which follows, given in an illustrative and non-limiting manner, with reference to the drawings in which:

- Figures IA and IB are side view sections of a * I curvature limiter according to the invention in a rectilinear configuration, respectively without flexible pipe (Figure IA) and with flexible pipe (Figure IB),

- Figure IC is a sectional side view of a curvature limiter in maximum curvature configuration,

- Figure 2 is a sectional side view of a common element of the curvature limiter of Figure 1, having reported lower stops,

- Figure 3A is a section along the plane AA of Figure 2,

- Figure 3B is a variant of Figure 3A, in which the current element is made of two half-shells assembled together,

- Figure 4A is a front view in direction B of Figure 2 of the lower stop of a current element,

- Figure 4B is a top view in the direction C of Figure 2 of the approach of the lower stop of a current element N comprising a first sleeve towards the corresponding stop of the current element N + 1 comprising a second sleeve connected end to end to the first sleeve by an upper fixing and articulation device 6, the two stops being initially offset laterally by a value "e" corresponding to the play in the lateral direction of the axis of rotation YY 'between a first fixing and articulation element 6i of the first sleeve relative to the second fixing and articulation element 6 ₂ of the second sleeve,

- Figure 4C illustrates the final approach phase following the preliminary phase of Figure 4B, the two stops of the elements N and N + 1 being in contact and having an effect of recentering in the same longitudinal direction XX 'of the two elements N and N + 1 due to the dihedral shape of the contact surfaces of the stops. C / \ l 't

- Figure 5 is a side view of a curvature limiter equipped with a winch and a cable to impose by traction on said cable, a maximum curvature to said curvature limiter,

- Figures 6A-6B detail in sectional side view a locking device at the lower stops of two adjacent current elements N and N + 1, respectively in a rectilinear configuration (Figure 6A) and in a locked maximum curvature configuration (Figure 6B),

- Figures 7A, 7B and 7C illustrate in side view the start of the installation of a flexible pipe equipped with a curvature limiter according to the invention respectively at the start of unwinding of the flexible (Figure 7A), in installation ( figure 7B) the flexible sliding freely in the curvature limiter up to the dimension L _o , where said curvature limiter is locked on said hose, then in running installation after said curvature limiter has passed the aft chute of the laying vessel (figure 7C),

- Figure 8 illustrates the following phases, in which the curvature limiter is positioned near an attachment point, then suspended from the latter, said attachment point being integral with a riser consisting of a pipe rigid steel,

- Figure 9A is a horizontal section in top view of the riser of Figure 8 at the level of a support having a double attachment point allowing the attachment of two curvature limiting devices on respectively the two diametrically opposed faces rigid driving,

- Figure 9B is a side view relating to Figure 9A detailing the two attachment points of said support and a buoyancy element integral with the riser,

- Figure 9C is a variant of Figure 9B of a support (/ J. · * · comprising three attachment points with a curvature limiting device and a flexible pipe suspended from one of the three points of hanging,

- Figure 10A shows a side view of a central current element 4b equipped with a lifting ring 4bj and a single locking device 3, comprising a strap 3a passing through the two holes 3b of the sleeve 5 of the central element 4b,

- Figure 10B shows in cross section, the curvature limiter at the level of the strap 3a in the blocking position of the pipe 2 inside the device 1,

- Figure 10C shows in cross section, the curvature limiter at the level of the strap 3a in the released position allowing free longitudinal, lateral or rotational displacement along the axis XX 'of the pipe 2 relative to the curvature limiter device 1,

- Figures 11A and 11B show an embodiment in which the sleeve 5 of a current element 4 of the curvature limiting device 1 comprises a first fixing and articulation element 6i at one end comprising a single first flat part and a second element fixing and articulation 6 ₂ at its other longitudinal end comprising two second flat pieces of the same shape as said first flat piece, the two second flat pieces therefore forming two flat pieces spaced from each other by a distance slightly greater than the thickness of the single flat part of the first fixing and articulation device 6], in top view (FIG. 11A) and in cross section showing the intercalation of the single flat part of the first fixing and articulation element 6i d 'a first sleeve between the two flat pieces of the second fixing and articulation element 6 ₂ at the longitudinal end of a second sleeve which is fixed to it,

- Figures 12A and 12B show an embodiment t

preferred in which each of the two first and second fixing and articulation elements 6i and 6 ₂ respectively at the two longitudinal ends of the sleeve 5 of a current element 4 of the curvature limiting device 1 comprises two same flat parts spaced apart from one of the other and offset with respect to a radial axial plane P _o such that a flat part of each of said first and second fixing and articulation elements 6i and 6 ₂ is interposed between the two flat parts of the second and respectively first fixing elements and articulation 6i and 6 ₂ of respectively two sleeves which are attached to them end to end to the two longitudinal ends of the current element 4 shown in top view in FIG. 12A and in cross section in FIG. 12B at the level of two said first and second fixing and articulation elements 6! and 6 ₂ interspersed,

- Figures 13A and 13B show a side view in longitudinal section two common elements 4 of a curvature limiting device, fixed to each other at a fixing device and upper articulation 6 and in the position of maximum curvature, their lower stops and 7 ₂ being in contact with one another, the first and second articulation and fixing elements 6 _t and 6 ₂ and the two lower stops 7 _t and 7 ₂ of the two first and second sleeves 5 of the two current elements 4, (N and N + l) fixed to each other being of the same shape, but arranged symmetrically (figure 13A) or being of different shapes and in non-symmetrical arrangements (figure 13B ).

In Figure IA, there is shown in section in side view a curvature limiter 1 according to the invention in a rectilinear configuration. In Figure IB it is installed around a flexible pipe 2 and secured to the latter at the level of two locking devices 3 shown in the released position 3a in Figures 10A and 10C, and in the locked position 3b in Figures 10A and 10B .

In FIG. IC, said curvature limiter 1 is shown in the configuration of maximum curvature (radius R _o ), said curvature being (a /.

less than the limit curvature (R> Ro) that the said flexible pipe 2 can withstand without damage.

The curvature limiter consists of the assembly of elements hinged together, namely a plurality of common elements 4, two end elements 4a, preferably identical, and a central element 4b comprising a device for locking 3 on the flexible pipe 2 as well as a lifting ring 4bj allowing the hooking of the curvature limiter device on a support which will be described later in the description of the invention,

Figure 2 shows a sectional side view of a common element consisting of a sleeve or tube with a circular section, the inside diameter of which is machined, at each of its ends, in the shape of a cone 5a flared outwards, c 'That is to say of increasing diameter from the running part 5b towards the end 5a, so as to avoid angular contact with the flexible pipe 2, and therefore dangerous for the integrity of the latter.

The curvature limiter 1 consists of a plurality of current elements 4 fixed to each other successively end to end by upper fixing and rotational articulation devices 6 at their two longitudinal ends, with further two terminal elements 4a comprising a single fixing and articulation device 6 at one of their longitudinal ends, fixed to the single current element 4 which is fixed to them.

Each current element 4 or terminal element 4a of the curvature limiter 1 consists of a tubular sleeve 5 of circular section, the internal diameter of which is greater than the external diameter of the flexible pipe 2, the latter thus being able to be threaded freely within it. , when the locking devices 3 are in the released configuration.

Each sleeve 5 of current element 4 comprises at its two longitudinal ends, respectively two first and second

A 'fixing and articulation elements 6 _{1 #} 6 ₂ arranged on the upper face of the sleeve and each comprising an orifice 6a of axis YY', ΥιΥ /, Y2Y2 'perpendicular to the direction XX', XjXf, X ₂ X ₂ ' axial longitudinal axis of said sleeve.

Each said fixing and articulation device 6 of two first and second sleeves consists of a first fixing and articulation element 61 of the first sleeve, and a second fixing and articulation element 62 of the second sleeve, arranged so that their orifices 6a are arranged opposite each other, said orifices 6a being traversed by a pin 63 forming a part having an axis of rotation of said fixing and articulation device 6 ensuring the connection between the two first and second sleeves.

Preferably, said first fixing and articulation element 61 at a first end of said sleeve consists of two first perforated flat pieces hereinafter referred to as fixing lugs 6ja, 6jb each comprising two opposite flat faces all extending in parallel planes in said axial longitudinal direction XX 'of said sleeve.

A single flat face called “first face” of one of the two first flat parts or fixing lugs 61a, 6] b is included in a longitudinal axial plane or radial plane P _{o of} said sleeve, said first flat face being opposite. -vis, substantially in the same substantially radial plane P _{o as} a second flat face of a flat part of said second fixing and articulation element, at the longitudinal end of a second sleeve which is fixed to it as described below.

Likewise, preferably, a second fixing and articulation element 6 ₂ at the other longitudinal end of said sleeve consists of two second perforated flat parts or fixing lugs 6 ₂ a, 6 ₂ b each also comprising two opposite parallel flat faces. extending in the axial longitudinal direction Ca / t

of said sleeve, a single flat face called “second flat face” of one of the two flat parts of the second fixing and articulation element 6 ₂ , being included in a said substantially radial plane P _{o of} said sleeve.

The two flat pieces 6a, 6ib of said first fixing and articulation element 6j are spaced from each other by a distance d slightly greater than the thickness of one of the two flat pieces 62a, 62b of the second fixing element and articulation 62, namely a flat part of the second fixing and articulation element 62 comprising a said second flat face. This distance d is slightly greater than the distance between the two opposite flat faces of said flat part of the second fixing and articulation element 6 ₂ .

Likewise, the two flat pieces of the second fixing and articulation element 62 are spaced from one another by a distance d slightly greater than the thickness of the flat piece of said first fixing and articulation element 61 comprising a said first flat face, that is to say slightly greater than the distance between the two opposite flat faces of the said flat part of the said first fixing and articulation element 6 _} .

For example, the distance d between two flat parts or fixing lugs of the first or second fixing element and articulation

61.62 is greater by a value equal to 1 mm compared to the thickness of the flat parts of the second or respectively the first fixing and articulation element. This value corresponds to a clearance e of 1 mm in said direction of said axis of rotation YY ', ΥιΥ /, Y2Y2' of each flat part of said first or second fixing and articulation element 61, 62 of a first sleeve interposed between the two flat parts of the second or respectively the first fixing and articulation element.

*

The two pieces 6IA plates, 6 _2b of a first securing member and hinge 6, a first sleeve 6 and the two flat ₂ pieces a, 6 _2b of the second fastener and joint 6 ₂ d ' a second sleeve, are arranged offset relative to each other and relative to said radial plane P _o such that a flat part of each said first or second fixing and articulation element 6 _n 6 ₂ of a first sleeve is inserted between the two flat pieces of a second fixing and articulation element 6 ₂ of the second or respectively the first sleeve to which it is attached with the four holes 63 of the four flat pieces 6ja-6ib, 6 ₂ a-6 ₂ b traversed by the same pin 63 disposed transversely in a said direction of axis of rotation YY ', YiYf, Y ₂ Y ₂ ', the set of four flat pieces 6ia-6ib, 6 ₂ a-6 ₂ b and said pin 63 thus forming a said fixing and articulation device 6 between two first and second sleeves ons.

It will be understood that two first and second fixing and articulation elements 6 ₂ located respectively at the two longitudinal ends of the same sleeve do not form part of the same fixing and articulation device 6, but that their flat parts are nevertheless arranged in offset. with respect to each other and with respect to said radial plane P _o in the same way as the two first and second fixing and articulation elements 61 and 6 ₂ at the longitudinal ends facing two first and second fixed sleeves to one another.

The embodiment shown in FIGS. 12A and 12B in which each said first and second fixing and articulation elements 6p 6 ₂ comprises two flat parts is advantageous compared to the embodiment described in FIGS. 11A and 11B, in which one of the two first and second articulation and fixing elements 6j-6 ₂ have only one flat part.

Indeed, in Figures 11A and 11B, the axis of rotation YY 'and the pin 63 are constrained at the level of two shear planes p, and p ₂ , while in Figures 12A and 12B, the shear stresses oJ .

in the axial direction XX 'are taken at the level of three shear planes p _n p ₂ and p ₃ , which correspondingly reduces the stresses in said axis YY' and said pin 63. When each of said first and second fixing elements and articulation 61, 62 comprises two flat parts, with a flat part of each of said first and second fixing and articulation elements 61, 6 ₂ interposed between the two flat parts of the other second and respectively first fixing element and articulation 62, 61, there are three shear planes Pu P2 and p ₃ corresponding to the three flat faces of the two flat pieces of the first fixing and articulation element 61 arranged opposite or vis-à-vis the three flat faces of the two flat pieces of the second fixing and articulation element 62 resulting from this intercalation.

In addition, as shown in Figures 11B and 12B, the lateral guidance in the YY 'direction at the joint is improved in the case of said first and second fixing and joint elements 6 _lf 6 ₂ having two flat parts. , as shown in Figures 12A and 12B with respect to the case in which one of the first and second fixing and articulation elements 61, 62 comprises a single flat part, as shown in Figures 11A and 11B.

Indeed, although in both cases, the intercalation of the first and second fixing and articulation elements 6 _lf 6 ₂ at the level of a flat part at least of each of them between two flat parts of the other, confers a lateral guide preventing any lateral movement other than a reduced play e _n e2 in the direction of the axis of rotation YY ', that is to say at the level of the pin 63 passing through the perforations 6a, the maximum play e ₂ in figure 12B is less than the maximum clearance ei of figure 118. This results from the fact that in the embodiment of figures 11A and 11B, only the single flat part 6j of the first fixing and articulation element 61 is interposed between the two flat pieces of the second fixing and articulation element 6 ₂ , the two flat pieces of the second fixing and articulation element 6 ₂ coming buteroJ <I laterally only on one of their faces against the single flat piece of the first fixing element and articulation 6i.

At the two longitudinal ends of each sleeve 5, in the lower part thereof, substantially at the level of said radial plane P _o , that is to say substantially diametrically opposed to said first and second fixing and articulation elements 6j and 62 are are respectively disposed two stops 7d ₂ and 7 referred to as "lower stops". Said flat pieces 6ia-6ib, 6 ₂ a-62b and said stops 7i-7 ₂ are attached to the upper face and lower face respectively of the longitudinal ends of the sleeves 5 by bolting or preferably by welding. The faces are referred to as "upper" and "lower" because in general the curvature limiter 1 is positioned to support a flexible submarine line by creating a curvature with concavity facing the seabed 16, that is, i.e. downwards, in which case the stops 7i and 7 ₂ must be positioned on said lower faces, while the convex face of the curvature of the curvature limiter and of the flexible line are facing upwards, therefore requiring that the fixing and articulation devices 6 are reported on the upper faces upwards, that is to say towards the surface 17.

The lower stops 7j and 7 ₂ are not necessarily of the same shape, but, in all cases, they have a front face 7ja, 7 ₂ a of planar or three-dimensional shape such as when said stops ?! and 7 ₂ at the two opposite ends of two sleeves fixed to one another come into contact in the event of maximum rotation a of the fixing and articulation device 6 of the two sleeves, said end faces 7 a and 7 _t b of the two stops 7i and 7 ₂ have a common contact surface 7a which is preferably planar or three-dimensional.

Two adjacent common elements 4, articulated to each other by a fixing and articulation device 6, can either be in a rectilinear configuration R ">, as shown in FIGS. IA and IB, or have a curvature of radius R, up to the radius of minimum curvature R _o , <

corresponding to the contact between the front face 7ja of the current element N and the front face 7 ₂ b of the current element N + 1.

It should be noted that the curvature, shown downward in Figure 1C, can equally well be effected upward, in the opposite direction, i.e. in reverse curvature. In this case, there is no curvature limiting effect. This is advantageous because the curvature in this direction makes it possible to position the curvature limiter device 1 around a flexible pipe 2 during the storage and transport of the flexible pipe wound on coils, in particular on board laying vessels. 20 with a radius of curvature less than R _o , as will be explained further in the description with reference to FIG. 7A. On the other hand, this possibility of reverse curvature is advantageous when laying the curvature limiting device at sea, as will also be explained below in conjunction with FIG. 8.

In a non-preferred embodiment, shown in Figures 2, 6A, 6B and 13A, each said stop 7i-7 ₂ has a front face 7ia, 7 ₂ b planar in planes P ₂ , P ₂ comprising the axis of rotation YY 'of the fixing and articulation device 6. In this non-preferred version of the invention, the lower stop 7 _{1 (} 7 ₂ can be produced by simply milling the lower part of the longitudinal end of the tubular sleeve 5 according to the plane P _u P ₂ passing through the axis of rotation YY '. In this embodiment, the planes P ₂ and P ₂ are inclined by the same angle α / 2 with respect to the plane of transverse section perpendicular to the axis longitudinal X> Xi 'and respectively X ₂ X ₂ ' of the tubular sleeve 5, and the maximum angle of rotation of the longitudinal axis XiX / of the first sleeve of the element N with respect to the longitudinal axis X2X2 'of the second sleeve of the current element N + l being

at.

It is understood that the two planes Pj, P ₂ meet in a bisecting plane P3 when the two end faces 7ia and 7 ₂ a are in contact, the plane P ₃ being a bisector plane passing a bisector of the two longitudinal axes XiXi 'and X ₂ X ₂ '.

In a preferred version of the invention shown in FIGS. 4A-4B-4C, the stop 7i of the current element N has a face 7ia which is not flat, but in the form of a convex dihedron, comprising a plane Po of symmetry comprising the longitudinal axis ΧιΧ'ι, ΧςΧ'ϊ, as shown in Figure 4B, and the corresponding stop 7 ₂ of the adjacent element N + 1 has a front face 7 ₂ a of complementary shape of a concave dihedron. In this case, it is the edge 7b of the dihedron which is aligned with a straight line D _o passing through the axis of rotation YY '. Since there may be a lateral play e in the direction of the axis of rotation YY ', Y1Y1', Y2Y2 'at the fixing and articulation device 6, when the device 1 approaches the maximum curvature Ro , the two stops 7i, 7 ₂ can be offset in the direction YY ', YiYf, Y ₂ Y ₂ ' by a value “e” as shown in FIG. 4B. But, as soon as the 15 stops 7 _lz 7 ₂ come into contact, they are automatically refocused with the edges 7b of the dihedrons of the end faces 7ia, 7xb (and the sleeves N and N + l) aligned substantially in the same axial longitudinal plane at the radial plane P _o . And, thus, all the current elements 4 of the curvature limiter 1 are located with their longitudinal axes 20 XX ', X1X1', X2X2 'substantially in the same radial plane Po (ZOX). However, if the end faces _2a 7JA and 7 are planar, there is no refocusing this effect, but on the contrary, a combination of a plurality of decentering "e" at each of the fixing devices and articulation 6, and the device is then not stable laterally along the axis YY '. This may then result, under the effect of the currents, in lateral instabilities, therefore in alternating movements at the level of the contacting plane stops 7ia, 7ib, which may lead to wear, and therefore to an undesirable reduction in the radius of curvature R _o . Thus, the dihedral shape is very advantageous, because all the elements of the device are locked in the same radial plane P _o , and the flexible pipe is then safe, in the same way as on a trough in structure. mechanically welded from the prior art. CaJ

Shapes other than complementary concave-convex dihedrons as described above, can provide a recentering of common elements with respect to each other, such as complementary curved shapes, in particular complementary concave-convex circular shapes or concave parabolic shapes. - complementary convex. Nevertheless, the dihedral remains a simple shape to machine and as such constitutes the preferred version of the invention.

In all cases, the maximum angle of rotation a between the longitudinal axes XjXi 'and X ₂ X _a ' fixed to each other by means of a said fixing device and articulation 6 is about 20 ° as shown. in the figures, so that, when - as shown in figure IC - the curvature limiting device 1 comprises five common elements 4 and two terminal elements 4a fixed to each other end to end, by respectively six fixing and articulation devices 6 spaced apart from each other by the same distance Li and positioned with the axes of rotation YY ', YjYi', Y ₂ Y ₂ 'at the same distance L ₂ from the longitudinal axes XX', XjXi ', X2X2' of the sleeves, both longitudinal axes of the two terminal elements 4a form an angle of 6 x 20 = 120 °, corresponding to a radius of curvature R _o = 1.68m, when L] = 0.7m and L ₂ = 0.3m.

In FIG. 3B, a cross-sectional front view is shown of an alternative embodiment of the common elements in which the tubular sleeve 5 is produced in two half-shells 5i and 5 ₂ . Each of the half-shells has on either side fixing lugs, respectively 81 and 82, secured for example by welding to said half-shells, and assembled together by bolts 8a, not shown. This arrangement is advantageous, because it allows the installation of a curvature limiter 1 on a flexible pipe 2 completely finished, that is to say including its end connectors. Indeed, the curvature limiter 1 of FIG. 3A requires passing said flexible pipe 2 through all of the Ca / “J elements 4 of the curvature limiter 1 before being able to mount the end connectors which are generally bulky. and therefore cannot pass through said curvature limiter 1.

The end elements 4a of the curvature limiter 1 have a hinge 6 and a stop 7i, 7 ₂ only on one side. At the second end, devoid of articulation 6 and of stops 7i, 7 ₂ , a curvature transition element 4a _n known to those skilled in the art, of cylindrical-conical shape made of elastomer or thermoplastic material, is advantageously installed. , such as polyurethane, and secured to said end of said element 4a. All the other parts of the curvature limiting device, namely the sleeves 5, stops 7i, 7 ₂ and flat parts 6ia-6ib, 6 ₂ a-6 ₂ b and pin 63 constituting the fixing and articulation devices 6 are advantageously produced by steel.

As shown in FIG. 10A, the sleeve 5 of the central element 4b of the curvature limiter 1 is surrounded by an annular peripheral central reinforcement 4b ₂ on which is installed on the upper face of the sleeve 5 a suspension ring 4bi which is connected a small length of chain 11, not shown in this figure, but shown in Figure 9C. A locking device 3 comprising a strap 3a and two openings 3b arranged symmetrically with respect to a radial plane PO on the upper part of the sleeve 5 such that the strap 3a passes through the two openings is advantageously placed on the same central element 4b. 3b and above the upper face of the flexible pipe 2 inside the sleeve 5 and below the underside of the sleeve 5 outside the openings 3b. Thus, when the strap 3a is stretched, the flexible pipe 2 is pressed against the internal wall of the sleeve 5 on the side of its lower face, so as to prevent said flexible pipe from being able to slide freely along the axis XX 'or in a lateral direction perpendicular to the axis XX ', or even turn on itself around the axis XX'. Said locking device 3 is shown in the released position in Figures IA, IC and 10C, and in Ca /

locked position in Figures IB, 10A and 10B.

In Figures 7A-7B-7C and 8, there is shown in side view the main phases of installation of a flexible pipe 2 equipped with a curvature limiter 1 according to the invention, from a ship of installation 20. In FIG. 7A, the hose 2 previously stored wound on the reel 19 is unwound and the end of the hose 2 (not coiled) equipped with the curvature limiter 1 rests horizontally on a support 20b placed on the bridge 20a of the laying vessel 20, such that the flexible pipe 2 is substantially tangent to the curved surface of a laying chute 20c generally located at the rear of the vessel 20. When storing the hose 2 on the spool 19, the curvature limiter 1 is in reverse curvature, therefore has no curvature limiting effect, which does not present a problem, since there is no tension in said flexible pipe 2 at this stage. Then, the curvature limiter 1 is secured to its support 20b and the laying of the pipe 2 running inside the fixed curvature limiter device 1 as shown in FIG. 7B begins. When a certain length L _o of flexible pipe 2 has been unwound (the length L _{o being} understood as the length of flexible pipe 2 from its submarine end), the laying is stopped, that is to say stops unwinding the flexible pipe 2 and the curvature limiter 1 is disconnected from its support 20b and the curvature limiter 1 is locked on the flexible pipe 2, then the installation is resumed as shown in FIG. 7C.

FIG. 8 shows a side view of an FPSO 12 anchored on site at 12a and comprising a bottom-surface connection as described in the applicant's patent WO-2009-138609, and comprising a steel riser 14 integral with a base or underwater equipment 15 anchored to the seabed 16. It is connected at the top to a flexible pipe 2 connected to the FPSO, said flexible pipe 13 comprising over part of its length to from the pipe 14 a plurality of floating elements 13b and, on the part of the side of the floating support 12, a plunging chain shape 13a. A hooking support 10 shown in FIG. 9A in section along a substantially horizontal plane and in FIGS. 9B-9C in side view, intended to receive the device, has previously been installed at approximately 2/3 of the height of the water. hooking device 9 for curvature limiter 1.

Thus, in this same figure 8, the different installation steps are:

- step 1 /: the flexible pipe is unwound from the laying vessel 20, the end of the flexible pipe having been hooked to the floating support 12, so that the underwater part of the flexible pipe takes the form of a chain plunging 2a, the curvature limiter then being in a slightly inverted curvature configuration.

- step 2 /: the curvature limiter 1 is approached towards the vertical riser 15 14 at the level of a hooking support 10, the curvature limiter still being in the reverse curvature configuration, using the underwater ROV 21 piloted from the laying vessel 20. Then, the suspension chain 11 of the curvature limiter 1 is hooked onto the hooking support 10a, the flexible submarine pipe 2 still being in the form of a plunging chain 2b with its point of lower horizontal tangency i located in the part of the chain 2b located between the floating support 12 and the hooking support 10, the laying vessel 20 continuing to move away from the floating support 12 on the other side of the pipe 14 relative to the floating support 12.

- step 3 /: the removal of the vessel 20 and the laying of the pipe 2 are continued, the curvature of the curvature limiter 1 changing direction and then having a concavity turned downwards, the radius of curvature decreasing to a minimum limit radius of curvature R _o which is reached when the stops 7j and 7 ₂ of the various sleeves 5 of the curvature limiter 1 are in intimate contact. At this stage, the flexible pipe 2 comprises two portions in the form of a plunging chain, on either side of the curvature limiter 1, namely a first chain CnJ

* plunging 2c between the floating support 12 and the curvature limiter 1, and a second plunging chain 2c 'between the curvature limiter 1 and the laying vessel 20.

- step 4 /: as soon as the flexible pipe 2 rests on the seabed 16, it adopts a simple chain curvature 2d, and the removal of the flexible pipe 2 on the bottom 16 continues by moving away from the vessel 20 towards the wellhead of destination.

The attachment support 10 described in FIGS. 9A-9B-9C is secured to the rigid riser 14, for example by welding and extends laterally in the form of a bracket in the direction Y ₃ Y ₃ ', so that that the attachment point, consisting of a single notch 10a is offset from the outer wall of the rigid pipe, by a distance greater than the maximum outer radius "r" of the curvature limiter, preferably greater than twice said said radius "r". As illustrated in Figures 9A-9B. Advantageously, the support bracket 10 extends on either side of the rigid pipe 14 in the direction Y3Y3 'perpendicular to the axis Z ₃ Z ₃ ' of the pipe 14, preferably symmetrically, which allows the installation of two flexible pipes 2 equipped with a curvature limiter according to the invention 1 on the two diametrically opposed faces of the rigid pipe 14.

In the case of umbilicals or electric cables of small diameter, for example from 40 to 75 mm, therefore of low linear weight, there is advantageously a plurality of attachment points 10a on each of the brackets, so as to install, preferably in a substantially symmetrical manner in terms of vertical load, a plurality of flexible pipes 2 at the same hooking height on the rigid pipe 14, as shown in FIG. 9C. A heavy flexible pipe 2 equipped with a curvature limiter 1 is suspended from the notch 10a of the bracket 10 closest to the pipe 14 to the left of the rigid pipe 14, a second notch 10a located on the opposite side, therefore to the right of the rigid pipe being intended to receive a second flexible pipe, therefore to the right of the rigid pipe, is ready to receive a second flexible pipe of similar characteristics, a third notch 10a furthest from the pipe to the left of said pipe rigid 14 being intended to receive a third lightweight flexible pipe. Thus, in the case of multiple attachment points 10a, to limit the bending forces in the brackets 10 and in the rigid pipe 14, the heaviest flexible pipes will preferably be installed as close as possible to the rigid pipe, the pipes light hoses being advantageously installed outwards.

Advantageously, as shown in FIG. 8, there is a plurality of hooking supports 10 at different heights, so as to avoid interference between the different flexible pipes installed on the same hanging support 10.

The own weight of the flexible pipe or pipes 2 suspended between the seabed 16 and the FPSO 12, as well as the own weight of the curvature limiter (s) 1, being taken up mainly at the level of the hooking support 10, advantageously available at said hooking support 10 a buoyancy element 10i which then compensates either partially or totally, if necessary in excess, said dead weight of all the elements, namely brackets 10, flexible pipes 2 and curvature limiters 1 , suspended on the pipe 14.

Certain flexible or umbilical conduits have a relatively great stiffness and under their own weight the desired maximum curvature R _o corresponding to the contacting of the adjacent stops 7j (element N) and 7 ₂ (element N + 1), cannot be reached. . To prevent the curvature limiter 1 from permanently deforming during movements of the FPSO 12 and the riser 14 under the effects of swell, wind and sea currents, the curvature limiter 1 is advantageously constrained by so that all the adjacent stops 7i ~ 7 ₂ remain permanently in intimate contact, thus ensuring a maximum stable radius of curvature equal to R _o . A6i /

For this purpose, as shown in sectional side view in FIG. 5, a longitudinal end of the curvature limiter device 1 is advantageously installed, on the lower face of the last element 4a of the curvature limiter 1, a traction means, such as a winch 9a connected to a cable 9b, the second end of the cable being connected to an attachment point 9c integral with the left end of the other terminal element 4a of said curvature limiter on the lower face. Thus, during all the phases of the installation of the flexible pipe 2 described with reference to Figures 7A-7B-7C and 8, the cable 9b is kept loose. When the curvature limiter 1 is in the final position, hooked on the notch 10a, as described in figure 9C, the ROV 21 actuates the winch 9a so as to tension the cable 9b and thus to force the curvature limiter 1 to bend until the stops 7i-7 ₂ of two adjacent elements 4, 4a are in intimate contact. The winch 9a has a locking device, not shown, which then maintains the cable 9b in permanent tension, which thus guarantees a constant minimum radius of curvature Ro throughout the life of the installation.

In a preferred version of the invention shown in FIGS. 6A-6B, is advantageously installed on the adjacent stops 7! -7 ₂ of the respective elements 4,4a N and N + 1, a device for blocking the stops 7c consisting of a hook 7iC articulated at 7 _t d on the stop 7i of the element N, a thrust spring 7je maintains said hook 7jC in the engaged position 7jf. The stop 7 ₂ integral with the element N + 1 has a cusp 7 ₂ c intended to cooperate with the end of the hook 7iC. Thus, when the stops 7r7 ₂ of the elements N and N + l approach each other, the hook 7tC in contact with the stop 7 ₂ , moves away taking the position 7 _t g, then once the stops 7 _r 7 _{2 are} in contact intimate, said hook having crossed the cusp 7 ₂ c resumes its locked position 7if, as illustrated in Figure 6B. When all the hooks 7îC are locked, the curvature limiter 1 is then locked in the final position and the radius of curvature R _o is then ensured permanently.

JUNE 2013

CABINET CAZENAVE »rl

Industrial property

ΙΓΒ.Ρ. 500 YAOUNDE, Cameroon

Phone. 22 21 32 89 - Fax: 22 20 64 14

E-mail: cab1netcazenave@iccnet.cm

Claims (6)

- 1 / said curvature limiting device (1) is arranged in a rectilinear position on the deck of a laying vessel (20), and said flexible line (2) is unwound from a spool (19) on the ship's deck ( 20) by passing the flexible line (2) through said curvature limiting device in a fixed position on the ship's deck, and 1. Curvature limiter device (1) forming a tubular member capable of adopting a rectilinear position or a variable curvature by preventing a radius of curvature less than a given minimum radius of curvature (R _o ) and thus allow a controlled variable curvature or the absence of curvature of a flexible line (2) threaded inside said tubular member, said tubular member comprising a plurality of tubular sleeves (5) arranged end to end at their longitudinal ends, preferably at least 3 sleeves, more preferably from 3 to 9 sleeves, characterized in that said sleeves (5) are fixed to each other by fixing and rotating articulation devices (6) arranged on the upper face of each of said sleeves, at the level of their longitudinal ends, said fixing and rotating articulation devices (6) allowing rotation of the longitudinal axis (XX ', XjX /) of a first sleeve (5, N) relative to the longitudinal axis (XX ', X2X2') of a second sleeve (5, N + 1) fixed to said first sleeve by means of said fixing and articulation device (6), said rotation is making around an axis of rotation (YY ', ΥιΥ /, Y2Y2') perpendicular to the two said longitudinal axes (XX ', XjX /, X2X2') of said first and second sleeves, preferably the two axes of rotation (ΥιΥ /, Y2Y2 ') of the two fixing and articulation devices (6) arranged at the two opposite longitudinal ends of each sleeve being arranged at the same distance (L ₂ ) from the longitudinal axis (XX', ΧιΧ /, X ₂ X ₂ ') of the said sleeve 25, said sleeve further comprising at their two longitudinal ends respectively two complementarily shaped stops (7i, _7a), disposed against the undersides of said substantially diametrically opposite sleeves relative to said fasteners and articulation (6), the two end faces 30 (7 ia, 7 ₂ a) of the two stops (7 _lz 7 ₂ ) at the longitudinal ends facing said first and second sleeves (5, NN + l) being spaced from each other when said tubular member is (λ / «· * I in a rectilinear position, and having a common contact surface (7a) when the two said stops are in contact with each other by the maximum authorized rotation (a) of the two lower faces of the two said sleeves towards each other thanks to said fixing and articulation devices (6). - 2 / the end of said flexible line is hooked to a said floating support (12) on the surface, and 2. Device according to claim 1, characterized in that said contact surface (7a) of said stops (7 _If 7 ₂ ) comprises at least one plane. - 3 / one continues to unwind said flexible line through said curvature limiter, while moving the laying vessel (20) away from said floating support (12), so that said flexible line adopts the form of a plunging chain (2a ), and 3. Device according to claim 1 or 2, characterized in that said front faces (7ja, 7 ₂ a) of two stops comprise three-dimensional surfaces of complementary shapes, respectively concave and convex, so that said contact surface (7a) has a three-dimensional shape preventing any lateral movement of the two said first and second sleeves (5, N-N + 1), with respect to each other, in a direction perpendicular to one of said longitudinal axes (XjXi ', XîXî ') of said first and second sleeves, and having an effect of centering the longitudinal axes (XiX', X ₂ X ') of said first and second sleeves substantially along the same longitudinal axial plane P _o when the two said stops (7 _t , 7 ₂ ) come into contact with each other. - 4 / when a given length (L _o ) of flexible pipe has been unwound by passing through said curvature limiting device in the rectilinear position, said curvature limiting device is locked on said flexible line using a device locking device (3), said curvature limiting device then being driven with said flexible line being removed, the curvature limiting device being in reverse curvature configuration with a low curvature with concavity facing upwards, and 4. flexible submarine line (2) being controlled by a said curvature limiting device disposed at an intermediate depth between the seabed (16) and the surface (17), comprising the following successive steps in which: 4. Device according to one of claims 2 and 3, characterized in that said contact surface (7a) is formed of two planes arranged in a dihedral, having a common edge (7b), said edge (7b) being preferably arranged in alignment with a straight line (D _o ) in intersection with said axis of rotation (YY ', YiYf, Y2Y2') of said corresponding fixing and articulation device (6). - 5 / the curvature limiter device is approached to a vertical rigid pipe (14) or it is suspended from a float in the subsurface and the unwinding of said flexible line is continued so that the curvature limiter adopts a said maximum curvature (R _o ) with its concavity facing downwards, said curvature limiter thus delimiting two portions of flexible line in the form of a plunging chain (2c) between, on the one hand, said floating support (12) and said curvature limiting device (1 ) and on the other hand said curvature limiting device (1) and said laying vessel (20), and CaJ é * α 5. Device according to one of claims 1 to 4, characterized in that the two said stops (7 _lf 7 ₂ ) at said longitudinal ends vis-à-vis two said first and second sleeves fixed one to the 'other, comprise blocking elements (7c, 7jc-7 ₂ c), able to retain said stops blocked against one another as soon as they (/ J come into contact with one another at the level of a said contact surface in the event of said maximum rotation (a). 6. Device according to one of claims 1 to 5, characterized in that said fixing and articulation device (6) of two first and second sleeves comprises: a first fixing and articulation element (6i) comprising at least a first part (6ja, 6ib) defining at least a first planar face arranged in a said radial plane (Po) on the upper face of said first sleeve at its longitudinal end opposite -vis said second sleeve, said first part (6ia, 6ib) comprising a circular orifice (6a) at the level of said first flat face, said orifice (6a) transversely crossing at least said first part in a direction of said axis of rotation (YY ', YiY /, Y ₂ Y ₂ ') perpendicular to said axial longitudinal directions (XX ', X1X1', X2X2 ') of the two first and second sleeves, and - a second fixing and articulation element (62) comprising at least a second part (62a, 6 ₂ b) defining at least one second flat face arranged in a longitudinal axial plane (Po) of said second sleeve on the upper face of said second sleeve at its longitudinal end facing said first sleeve, said second part (62a-6 ₂ b) comprising a circular orifice (6a) at said second flat face, said orifice (6a) transversely crossing at least said second part in the direction of said axis of rotation (YY ', YiYf, Y ₂ Y ₂ ') perpendicular to said axial longitudinal directions (XX ', ΧιΧ /, X2X2') of the two first and second sleeves, and - a pin (63) crossing transversely at least said first and second parts (6ia-6ib, 6 ₂ a-62b) at their said orifices (6a) .oJ 7. Device according to the preceding claim, characterized in that: said first fixing and articulation element (6j) comprises at least one said first perforated part (6ja, 6jb) respectively defining two plane faces, parallel, facing each other, including a said first face, said two flat faces delimiting a empty space and being arranged at a distance from each other, and said second fixing and articulation element (6 ₂ ) comprises at least one second flat part (6 ₂ a-6 ₂ b) comprising two opposite flat faces parallel including at least one said second face, - said second flat part (6 ₂ a, 6 ₂ b) of a first sleeve (5, N) being fixed to and interposed between the two said planar faces facing said first fixing and articulation element (6i ) of a second sleeve (5, N + 1), such that the orifices (6a) of the two opposite flat faces of said second flat part are arranged vis-à-vis the orifices respectively of the two flat faces of said first fixing and articulation element (6j). 8. Device according to the preceding claim, characterized in that said fixing and articulation device (6) comprises: a said first fixing and articulation element (6i) at the end of a said first sleeve (5, N) comprising two said first perforated flat pieces (6ia-6jb) each comprising two parallel opposite flat faces, the first two pieces plates being arranged parallel side by side at a said distance from each other, and - a said second fixing and articulation element (6 ₂ ) at the longitudinal end of a said second sleeve (5, N + l) comprising two said second perforated flat pieces (6 ₂ a-6 ₂ b) each comprising two opposite planar faces parallel, the two CVs second flat parts being arranged parallel side by side at a said distance from one another, a said first flat part (6 _t a) of said first sleeve being interposed between the two said second parts of the second sleeve, and a said second flat part (6 ₂ a) of the second sleeve being interposed between the two said first flat parts of the first sleeve, and the same said pin (6 ₃ ) being arranged through the orifices (6a) two said first flat pieces of the first sleeve and two said second flat pieces of the second sleeve thus interposed. 9. Device according to one of claims 1 to 8, characterized in that it comprises a locking device (3) for locking a said flexible line (2) inside said curvature limiting device (1), thus preventing their lateral and / or longitudinal relative movement, the internal diameter of said sleeve being greater than the external diameter of said flexible line. 10. Device according to claim 9, characterized in that said locking device (3) comprises at least one strap (3a), preferably at least two straps (3a), each strap (3a) passing through two orifices (3b ) at the periphery of a sleeve, preferably a central sleeve (5b) of said tubular member, the two orifices (3b) being arranged close to one another and positioned at the same level in the longitudinal axial direction ( XX ') of said sleeve, each strap (3a) encircling, at least partially, said flexible line (2) inside said sleeve and exiting at its two ends through the two orifices (3b) respectively. 11. Device according to one of claims 1 to 10, characterized in that each said tubular sleeve (4) is composed of two half-sleeves with semi-circular sections (5 _t -5 ₂ ) fixed one to the other. CaJ 12. Device according to one of claims 1 to 11, characterized in that it comprises at one longitudinal end on its underside a winch (9a) and a cable (9b) wound at one end around said winch, the other end of the cable being hooked to a hooking element (9c) disposed at the other longitudinal end of said tubular member on its underside, allowing said cable to be tensioned by actuating said winch and winding said cable around said winch and, thus, to thus bring the two longitudinal ends of said tubular member closer together to create a said curvature. 13. Bottom-to-surface connection installation between subsea equipment, such as a subsea wellhead or the end of a subsea pipeline resting on the seabed (16), and a floating support at the surface (12), comprising a flexible submarine line (2), the curvature of which is controlled by a said curvature limiting device (1) according to one of claims 1 to 12, said flexible line being threaded inside of said tubular member and said curvature limiting device being disposed at an intermediate depth between the seabed (16) and the surface (17). 14. Installation according to claim 13, characterized in that said bottom-surface connection comprises a hybrid tower consisting of a flexible pipe (13) extending from a said floating support (12) to the upper end of a rising rigid pipe or vertical riser (14), the lower end of which is connected to equipment (15) or to one end of an underwater pipe (18) resting on the seabed (16), said installation comprising in besides at least one curvature limiting device (1) hooked (10) to said riser, preferably comprising at least two curvature limiting devices (1) hooked at the same height against two diametrically opposed faces of said riser. 15. A method of depositing a submarine line (2) from a bottom-surface connection installation according to claim 13 or 14, from a laying vessel (20) on the surface (17), the curvature of said OR " - 6 / the removal of said flexible line is continued until the low point of horizontal tangency (i) of the plunging chain (2c) of the second flexible line portion between said curvature limiting device (1) and the surface laying vessel (20) reaches the seabed (16) and the laying on the seabed (16) of said flexible line is then continued by moving the laying vessel (20) away from the floating support ( 12) while unwinding said flexible line from the spool (19) on the deck of the laying vessel (20).