EP0698136B1 - Preform or matrix tubular structure for well casing - Google Patents

Abstract

This tubular structure comprises at least a braiding of flexible strands (10) made of fibres (100) that are interlaced with a certain amount of clearance so that the structure is capable of expanding radially whilst being constrained in an axial direction under the application of an overpressure inside the preform or matrix.

Description

The present invention relates to an assembly consisting of a preform tubular and of a recoverable matrix for the casing of a well, in particular a well of oil drilling.

In the present description, and in the claims, the expression “ term "casing" a tube for consolidating a well, by the term "preform" a structure tubular which is initially flexible and is then hardened to bind intimately and to remains against the wall of a well (thus constituting a casing), by the term "matrix" a flexible and recoverable structure used as a tool to dilate the preform and apply it against the wall of the well before it hardens.

The term "production tubing" refers to a tube coaxial with a casing, and smaller diameter, allowing the fluid produced by the well to be transported (water or oil especially).

The centering and sealing of this "tubing" in the casing is carried out by means of a hydraulically inflatable shutter, commonly designated by the term English "packer".

For casing an oil well as well as for applications similar, flexible and curable tubular preforms have already been proposed, intended to be placed in the folded state - state in which they have a space requirement weak radial - then to be unfolded radially, by applying pressure interior. According to this technique, which is notably described in the documents FR-A-2 662 207 and FR-A-2 668 241, the preform has, after radial deployment, a strictly cylindrical shape, of well determined diameter.

After installation in a well or a pipe, we proceed to hardening of the wall of the preform, for example by polymerization of this wall which has a composite structure composed of a resin impregnating filamentary sleeves. These sleeves ensure that the preform is inextensible radially.

According to these techniques, it is necessary to provide a casing diameter deployed which is slightly less than the diameter of the hole to be drilled so that the wall of the hole does not come to modify the cylindrical shape of the casing. The annular space as well formed, even if it is very small, or even zero in places, must most often be filled with cement to perfect the seal between the hole and the casing laid.

Furthermore, in its folded form, the tubular preform has a lower radial section of about half of its developed radial section, which in most cases is sufficient, but may not be sufficient for some applications. This is why, the objective of the present invention is to solve this problem by proposing a preform-matrix set whose structure presents a deformable geometry able to be applied to the walls of the tube hole (or casing to line) without however exceeding certain limits, this deformation being controlled and variable depending on the different applications.

Another objective of the invention is to propose an assembly whose preform has a significantly higher degree of expansion than those obtained with the devices known of the aforementioned genre, the expansion of the preform being done in two stages, all first by radial deployment, then by radial expansion.

We know from US-A-3 104 717 an inflatable shutter hydraulically ("packer") comprising an inflatable sleeve inside a tubular structure which is reinforced by a braiding of wicks allowing it to expand radially while restricting itself in the axial direction under the effect of an overpressure at inside said tubular structure.

Admittedly, the inflatable sleeve is removable in the event of degradation, but the assembly does not operate in normal service without the sleeve; moreover, the structure tubular is not polymerizable and cannot be hardened to be intimately and remains against the wall of the well.

The assembly which is the subject of the present invention consists of a radially expandable tubular preform, and a recoverable matrix serving as a tool to expand the preform.

a) ladite préforme possède une paroi en matériau composite formée d'une résine fluide et durcissable, par exemple polymérisable à chaud, confinée entre une peau ou membrane intérieure et une peau extérieure, toutes deux en matériau élastique, à l'intérieur de laquelle est noyée une structure tubulaire comprenant au moins un tressage de mèches souples et entrecroisées composées de fibres, qui l'autorise à s'expanser radialement tout en se restreignant en direction axiale sous l'effet d'une surpression à l'intérieur de la préforme ;

b) ladite matrice, initialement solidaire de la préforme, comprend un manchon gonflable intérieur à la préforme dans lequel il est possible d'introduire un fluide sous pression de manière à l'appliquer radialement contre la paroi intérieure de la préforme et réaliser l'expansion radiale à la fois du manchon et de la préforme, ladite matrice étant arrachable en fin d'opération, après durcissement de la préforme.

The objectives mentioned above are achieved thanks to the fact that:

a) said preform has a wall of composite material formed from a fluid and hardenable resin, for example heat-polymerizable, confined between an inner skin or membrane and an outer skin, both made of elastic material, inside which is embedded a tubular structure comprising at least one braiding of flexible and interwoven wicks composed of fibers, which allows it to expand radially while being restricted in the axial direction under the effect of an overpressure inside the preform;

b) said matrix, initially secured to the preform, comprises an inflatable sleeve inside the preform into which it is possible to introduce a pressurized fluid so as to apply it radially against the inner wall of the preform and carry out the expansion radial both of the sleeve and of the preform, said matrix being torn off at the end of the operation, after hardening of the preform.

In a preferred embodiment, this braiding comprises two series wicks symmetrically intersecting on either side of the generators of the tubular structure, that is to say in relation to its longitudinal axis, the wicks of each series being parallel to each other.

Preferably, each of the series of wicks forms an acute angle with the longitudinal axis which is between 10 ° and 30 °, and is preferably of the order of 20 °, when the structure is in its radially contracted state, while this angle is between 50 ° and 70 ° when the structure is in its radially expanded state.

Preferably, the locks are flat, affecting the shape of ribbons.

In one possible embodiment, the preform has several braided wick structures fitted coaxially one inside the other.

Preferably, the preform is flexible enough to be able to be folded in on itself longitudinally when the structure is in its state radially contracted.

So, during its installation in the well or in the pipeline, we start by unfolding it from one end to give it a shape approximately cylindrical, then its radial expansion is carried out, by deformation structure; deployment by unfolding and subsequent expansion are carried out by application of a fluid inside the preform.

• ladite peau extérieure de la préforme possède des reliefs ;
• ledit manchon gonflable est équipé d'un tube d'amenée de fluide dans le manchon ;
• la matrice est fixée à la préforme au moyen d'éléments de liaison sécables ;
• ledit manchon possède également une structure tubulaire composée de mèches souples entrecroisées ;
• certaines mèches du manchon sont remplacées par des fils conducteurs d'électricité permettant le chauffage de la préforme en vue de sa polymérisation, lorsqu'ils sont branchés à une source de courant.

Furthermore, according to a certain number of possible additional characteristics of the assembly forming the subject of the present invention:

• said outer skin of the preform has reliefs;
• said inflatable sleeve is equipped with a fluid supply tube in the sleeve;
• the matrix is fixed to the preform by means of breakable connecting elements;
• said sleeve also has a tubular structure composed of interlaced flexible wicks;
• certain wicks of the sleeve are replaced by electrically conductive wires allowing the preform to be heated with a view to its polymerization, when they are connected to a current source.

Other characteristics and advantages of the invention will become apparent from the description and attached drawings which show by way of non-limiting examples of preferred embodiments.

• les figures 1, 2, 3 sont des schémas représentant une préforme ou une matrice pourvue d'une structure tubulaire conforme à l'invention, cette préforme ou matrice étant représentée respectivement à l'état radialement contracté, dans un état intermédiaire et dans un état radialement expansé ;
• les figures 1A, 2A et 3A sont des vues de détail représentant le tressage de mèches souples constituant la structure, dans un état de déformation correspondant respectivement aux figures 1, 2 et 3 ;
• la figure 4 est une vue en perspective avec arrachement d'une préforme conforme à l'invention possédant plusieurs structures emmanchées les unes dans les autres ;
• la figure 5 est une section transversale, à plus grande échelle, de la préforme de la figure 4 ;
• les figures 6A et 6B sont des vues schématiques de la section de la préforme axialement repliée sur elle-même, dans deux configurations possibles différentes ;
• les figures 7 et 7' sont des vues similaires de l'une ou l'autre des préformes des figures 6A ou 6B, respectivement après déploiement et après expansion radiale ;
• la figure 8 est une vue similaire à celle de la figure 2A montrant une variante du mode de tressage de la structure ;
• la figure 9 est une vue schématique en coupe longitudinale, d'une matrice et d'une préforme toutes deux conformes à l'invention, au cours de la mise en place de la préforme dans un puits, matrice et préforme étant déployées, mais non expansées radialement ;
• la figure 9A est un détail à plus grande échelle de la zone de la paroi de la matrice et de la préforme qui est référencée A à la figure 9 ;
• les figures 10, 10A, 10B, 10C et 10D sont des vues schématiques destinées à illustrer les différentes étapes successives de la mise en place d'un tubage dans un puits de forage pétrolier au moyen d'un tubing de production, à l'aide de l'ensemble matrice - préforme de la figure 9.
• la figure 11 illustre un mode possible d'extraction de la matrice ;
• les figures 12 et 12A représentent le gonflage progressif d'une matrice au cours de la dilatation d'une préforme dans un puits.

In these drawings:

• Figures 1, 2, 3 are diagrams showing a preform or a matrix provided with a tubular structure according to the invention, this preform or matrix being represented respectively in the radially contracted state, in an intermediate state and in a state radially expanded;
• FIGS. 1A, 2A and 3A are detailed views showing the braiding of flexible wicks constituting the structure, in a deformation state corresponding respectively to FIGS. 1, 2 and 3;
• Figure 4 is a perspective view with cutaway of a preform according to the invention having several structures fitted into each other;
• Figure 5 is a cross section, on a larger scale, of the preform of Figure 4;
• FIGS. 6A and 6B are schematic views of the section of the preform axially folded back on itself, in two different possible configurations;
• Figures 7 and 7 'are similar views of one or the other of the preforms of Figures 6A or 6B, respectively after deployment and after radial expansion;
• Figure 8 is a view similar to that of Figure 2A showing a variant of the braiding mode of the structure;
• Figure 9 is a schematic view in longitudinal section, of a matrix and a preform both according to the invention, during the introduction of the preform in a well, matrix and preform being deployed, but not radially expanded;
• FIG. 9A is a detail on a larger scale of the area of the wall of the matrix and of the preform which is referenced A in FIG. 9;
• Figures 10, 10A, 10B, 10C and 10D are schematic views intended to illustrate the different successive stages of the installation of casing in an oil wellbore by means of production tubing, using of the matrix - preform assembly of Figure 9.
• FIG. 11 illustrates a possible mode of extraction of the matrix;
• FIGS. 12 and 12A represent the progressive inflation of a matrix during the expansion of a preform in a well.

The preform or the matrix designated 1 in FIGS. 1 to 3 has a tubular shape provided with a braided structure. This is made up of an intertwining of two series of flat wicks, or ribbons 10a, 10b which are wound in a helix to form the envelope of the structure. The two series are of opposite pitch, and the wicks are inclined at an acute angle u relative to the generatrix of the tube which it forms, which is cylindrical. To simplify the description, the axis XX ′ of the tube has been taken as a reference in FIGS. 1 to 3. The two series of wicks 10a and 10b are intertwined like a cane, symmetrically with respect to the axis XX ', on either side of the latter.

Advantageously, the angle u is of the order of 20 ° (Figures 1 and 1A).

Each of the locks 10 is formed from a plurality of fibers or of wires having a great mechanical resistance, and inextensible, joined the to each other. These are, for example, glass or carbon fibers having a diameter of a few micrometers, or steel wire.

As an indication, the wicks 10 have a width included between 1 and 6 mm, and a thickness between 0.1 and 0.5 mm.

Preferably, the material constituting the fibers or threads which form these wicks have a low coefficient of friction, favoring the mutual sliding of the intertwined locks, and consequently favoring the deformability of the structure.

As seen in Figure 2A, the braiding of the two series strands 10a on the one hand and 10b on the other hand is made with a certain play, giving a loose assembly which spares 11-shaped spaces diamonds at the intersection of the two series 10a, 10b.

In FIG. 1, the preform or the matrix is represented in the configuration which gives it the greatest possible length L1. In this state, the structure is self-locked, the different wicks being in support by their edges against each other. The preform has a minimum diameter D1.

It is possible to deform this structure, for example - as we will see later - by applying internal pressure to it.

This phenomenon is illustrated in Figure 2. We can increase the angle made by the wicks with the axial direction XX ', this deformation showing the spaces 11 already mentioned. In FIGS. 2 and 2A, the two series of wicks 10a and 10b are in an intermediate position, the angle v being for example of the order of 30 to 35 °. This deformation corresponds to an axial compression A of the structure and, correspondingly, to a radial expansion R. The structure thus has a length L2 less than L1 and a diameter D2 greater than D1.

This deformation can continue until the state illustrated in FIGS. 3 and 3A in which the structure will again lock up, the strands constituting the braiding again coming to bear against one another as shown in FIG. 3A. Preferably, the braiding is determined so that this blocking takes place when the angle w formed by the locks relative to the axial direction of between 50 ° and 70 °. The structure then has a minimum length L3 and a maximum diameter D3.

This deformation is of course reversible, and by pulling axially on the ends of the structure shown in Figure 3, it is possible to return it to the state of FIG. 1.

The braiding shown in FIGS. 1A to 3A is a braiding simple, in which a wick 10a alternately passes over and below a wick 10b, and vice versa. It goes without saying that others braiding modes can be considered, such as for example that shown in Figure 8. According to the latter, each wick 10a passes successively above and below two wicks 10b, and vice versa.

It should be recalled that the structure shown in Figures 1 to 3 is purely schematic, intended to explain the phenomenon deformability of the preform or matrix.

FIG. 4 shows a preform 1 capable of application industrial. This includes several deformable tubular structures such as that which has just been described, in this case four structures 3a, 3b, 3c and 3d coaxial, and of increasingly smaller diameters, fitted into each other. In practice, a higher number, per example of ten fitted structures can naturally be expected. They are confined between two skins made of elastic materials, for example elastomeric material one exterior 4 and the other interior 5. The role of the latter could be played by the wall of the matrix. They are impregnated with a fluid but curable medium, for example a resin thermosetting polymerizable hot, housed between the two skins 4 and 5.

The deformability of skins 4 and 5 is chosen for be compatible with that of braided structures 3, the deformation of the whole being done jointly, and with the same amplitudes.

Due to the fluidity of the medium 30 and the flexibility of the structures 3a to 3d, which can slide freely with respect to each other, it is possible to fold the preform longitudinally on itself. FIGS. 6A and 6B show two possible (non-limiting) modes of folding, respectively in the shape of a U and in the shape of a snail (spiral). Following such folding, it is therefore possible to give the preform a cross section having a very small footprint. By unfolding, the preform can be deployed, to give it the cylindrical shape shown in FIG. 7. Then, for example by applying an internal overpressure, it is possible to cause the radial expansion of the preform, by deformation of each of the concentric structures 3a , 3b, 3c and 3d by applying the phenomenon described above.

FIG. 9 represents a preform similar to that which comes to be described associated with a dilator tool intended to ensure its implementation place in a well, tool hereinafter called matrix.

Preform 1, shown in the unfolded state, but not expanded, includes - as already said - a medium 30 of thermosetting resin which occupies the annular space between two skins of elastic material one exterior 4 and the other interior 5 or 71 (of the sleeve 7). In this space are also located several deformable tubular structures and concentric formed by braided ribbons 3.

The matrix - referenced 6 - comprises a tubular sleeve 7 closed at its upper and lower ends by blanking plugs 60 respectively 61.

The upper plug 60 is crossed by a tube 8 which has openings 80 opening, like its free end, to inside the sleeve 7. Appropriate means not shown, allow a liquid under pressure to be introduced through the tube 8 inside of the sleeve 7, via a flexible conduit.

This liquid can be brought in from the surface. In variant, you can use liquid (mud, oil ...) present in the well, introducing it into the matrix using a pump equipping the latter.

The wall of the sleeve consists of two membranes elastic, for example of elastomeric material, the inner 72 and the other exterior 71. Between the two membranes is a structure tubular with braided wicks as described above, referenced 70. In a variant, several concentric structures can be provided, fitted into each other as is the case for the preform.

The length of the sleeve 7 is greater than that of the preform 1. End caps 60, 61 are fixed, for example by bonding, in the end zones of the inner membrane 72.

The sleeve 7 is fixed, by its external membrane 71, to the preform 1, by means of end sleeves 73, 74. These have rupture zones 730 and 740 respectively. The cuffs 73 and 74 form seals between the preform and the sleeve 7 constituting the matrix 6.

The interface between the outer membrane 71 of the sleeve and the inner skin 5 of the preform is treated, for example by coating with silicone, so that there is little adhesion between these two elements.

In one embodiment, the inner skin can be deleted.

Preferably, as seen in the detail in FIG. 9A, the outer face of the outer skin 4 of the preform has pads 40. These are for example annular bulges separated by cavities also annular 41. The function of these pads is to promote sealing with the wall of the well, and to keep a prestress and some flexibility after hardening.

Figure 10 and following illustrate the casing operation of an oil well through a production tubing by means of preform 1 and using the matrix which have just been described.

Has been designated by P and the borehole wall by the reference 9 the production tubing fitted to the wells, this tubing being retained and centered by a hydraulic valve - or "packer" - 90.

As an indication, the inside diameter of tubing 9 is 60 mm while the average diameter of the well is of the order of 180 mm. The preform is introduced by being folded back on itself, for example by snail (see Figure 6B) in such a way that the largest dimension of its cross section is less than the inside diameter of the tubing 9. This larger dimension is for example of the order of 55 mm. The preform is therefore lowered, at the same time as the tube 8, to the level desired inside the well. First, we will cause the deployment of the preform 1, making it take a cylindrical shape. Its outside diameter is then 90 mm. This is achieved by introducing inside the sleeve 7, via the tube 8, a fluid such as water under pressure.

This arrival of fluid is symbolized by the arrows f in FIG. 10A.

The pressure of the fluid is then increased, as illustrated by the arrows f 'in FIG. 10B. The radial expansion is thus achieved, both of the sleeve 7 and of the preform 1, by the deformation effect of the braiding which has been described with reference to FIGS. 1 to 3.

Of course, at the same time as this expansion takes place radial, there is a reduction in the length of the preform and the matrix. It thus reaches a diameter of 180 mm.

The preform is therefore applied intimately against the wall P of the well. The degree of expansion is done as needed, that is to say according to the roughness of the wall. This is an essential difference compared to the known flexible preform device, the radial expansion of which can only take place according to a well-defined diameter. The preform therefore adapts to the configuration of wells it encounters. This is further favored by the presence of the pads 40, which provide anchoring and sealing.

The wall of the preform is then allowed to harden, introducing and circulating a hot fluid (and under pressure) in the sleeve 7. When the polymerization is complete, the fluid is aspirated contained in the sleeve, which causes its radial retraction, as shown in Figure 10C.

By pulling upwards on the tube 8, it is then possible to tear off the whole of the matrix, by breaking the bonding zones breakable 730 and 740.

The sleeve 7 lengthens by retracting radially, and it is possible to extract it through tube 9.

The old preform 1, hardened, constitutes a casing element of Wells.

Such tubing can be used with or without cement, in depending on the soil conditions encountered.

It is of course necessary, when positioning the preform, in the well, to take into account its reduction in axial length, which will intervene during operation.

The extraction mode illustrated in Figure 11 does not require applying a vacuum inside the matrix.

Indeed, thanks to the braided structure, under the effect of traction F 'exerted on the matrix, the latter gradually shrinks in radial direction, from top to bottom, peeling off from casing 1 (already hardened).

The reference 7a designates the portion of the matrix already constricted, and detached from the casing, whose strands of structure form the angle u .

The reference 7b designates the expanded portion, the wicks of which form the angle w .

Figures 12 and 12A show a dilation of the matrix 7 and preform 1 which is done gradually, from the bottom to the top, an inflation liquid being introduced, via the conduit 8, to the part bottom of the matrix. Inflation progression can be obtained by example by enclosing the preform and the matrix (in the folded state) in a envelope suitable for tearing longitudinally and from bottom to top.

It goes without saying that the braided deformable structure conforms to the invention can be implemented with preforms, the implementation of which instead would not use inflation dies using such structure, and vice versa.

In one possible embodiment of the structure, certain fibers of at least some of the locks (and, advantageously of all the locks) are replaced by electrically conductive wires, allowing the preform to be heated or the matrix, for the polymerization of the preform, when they are connected to a current source.

This is especially interesting for a (reusable) matrix, the connections electrical at both ends of the structure presenting no difficulties particular.

Claims (12)

1. An assembly comprising a radially expandable tubular preform (1) for casing a well and a recoverable matrix (6) serving as a tool for expanding the preform, the assembly being characterized by the fact that :

   a) said preform possesses a wall of composite material formed by a resign that is fluid and settable (30), e. g. a hot-polymerizable resin, which is confined between an inner skin or membrane (5 ; 71) and an outer skin (4), both of elastic material, within which there is embedded a tubular structure comprising at least a braid of flexible strands (10) crossing over one another, thereby enabling it to expand radially while shrinking axially under the effect of pressure being applied to the inside of the preform (1) ;

   b) said matrix (6) which is initially secured to the preform (1) comprising an inflatable sleeve (7) inside the preform (1) into which it is possible to inject a fluid under pressure in such a manner as to press the matrix radially against the inside wall of the preform (1), thereby causing both the sleeve (7), and the preform (1) to expand radially, said matrix being suitable for being torn off at the end of the operation after the preform has set.
2. An assembly according to claim 1, characterized by the fact that the structure of its preform (1) comprises a braid of flexible strands (10) made up of fibers (100) and comprising two series of strands (10a, 10b) that cross over one another symmetrically relative to the longitudinal axis (XX') of the tubular structure, the strands in each series being parallel to one another.
3. An assembly according to claim 2, characterized by the fact that when the preform structure is in its radially contracted state, each of said series of strands (10a, 10b) forms an acute angle (u) lying in the range 10° to 30° and preferably about 20° relative to the longitudinal axis (XX').
4. An assembly according to claim 2 or 3, characterized by the fact that when the preform structure is in its radially expanded state, each of said series of strands (10a, 10b) forms an acute angle (w) lying in the range 50° to 70° relative to the longitudinal axis (XX').
5. An assembly up to any one of claims 2 to 4, characterized by the fact that said strands (10, 70) are flat, taking the form of tapes.
6. An assembly according to any one of claims 2 to 5, characterized by the fact that the preform (1) possesses a plurality of braided strand structures engaged coaxially within one another.
7. An assembly according to any one of claims 1 to 6, characterized by the fact that the preform (1) is sufficiently flexible to be capable of being folded up longitudinally when it is in its radially contracted state.
8. An assembly according to any one of claims 1 to 8, characterized by the fact that said outside skin (4) of the preform (1) possesses patterns in relief (40).
9. An assembly according to any one claims 1 to 8, characterized by the fact said inflatable sleeve (7) is fitted with a tube (8) for feeding fluid to the inside of the sleeve.
10. An assembly according to any one of claims 1 to 9, characterized by the fact that the matrix (6) is fixed to the preform (1) by severable link elements (73, 74).
11. An assembly according to any one of claims 1 to 10, characterized by the fact that said sleeve (7) also possesses a tubular structure made up of flexible strands (70) crossing over one another.
12. An assembly according to claim 11, characterized by the fact that some of the strands (70) of the sleeve (7) are replaced by electrically conductive wires enabling the preform to be heated for polymerization purposes, when said wires are connected to a source of electrical current.

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