EP0842347B9 - Device and process for the lining of a pipe branch, particularly in an oil well - Google Patents

Abstract

PCT No. PCT/FR96/01225 Sec. 371 Date Jul. 20, 1998 Sec. 102(e) Date Jul. 20, 1998 PCT Filed Aug. 2, 1996 PCT Pub. No. WO97/06345 PCT Pub. Date Feb. 20, 1997The device includes a radially deformable flexible tubular preform (1) that can be expanded by internal pressure and hardened in situ by heating its wall to polymerize it, the preform is formed of a rectilinear main section (10 and a rectilinear secondary section (11) at an acute angle ( alpha ) to the main section (10) and joined and sealed to the latter in a middle area (10c), temporary restraining bindings being provided to hold the secondary section initially in a radially folded condition, pressed against the main section (10), the combination then constituting a rectilinear preform, whereas after removal of the temporary restraining bindings (3), and due to internal pressure, the secondary section (11) separates from the main section (10), the combination then constituting a generally "y" shape preform adapted to be polymerized in the area of bifurcation of the well.

Description

The subject of the present invention is a device and a method for lining of a bifurcation of wells, in particular of oil wells.

The invention finds more especially application for the lining watertight in the junction zone between a main borehole generally (but not necessarily) vertical and bias drilling from the vertical well, bias drilling commonly referred to in the trade by the English term "side track".

In particular, this type of secondary drilling is used to access lateral oil tanks, once the main tank is depleted, has become insufficiently profitable, or simply to increase the productivity of a well.

This type of drilling also makes it possible to considerably extend the production area in areas with difficult access, without having to drill a new well surface ; this is particularly the case for the exploitation of deposits located under the sea.

With known methods, we use, to consolidate and seal the well drilled, metal casing, both for the main well and often for the secondary wells, and it is difficult to obtain in the junction zone good seal.

According to the technique used in document US-A-5 388 648, we practical by milling a window in a portion of the casing lining the primary well (vertical), to the right of the fork. Then, an expandable bladder is introduced into this well. with double envelope, having a configuration in general form of y, and one positions it at the bifurcation in such a way that its secondary branch is placed in the entrance to the secondary well. The bladder is inflated using a pressurized liquid, for example by mud which is injected into the space delimited by the two envelopes of the bladder. Once inflated, the bladder defines a peripheral free space, at the level of the window and in the entrance portion of the secondary well. We fill this space, by pumping from the surface, a curable liquid, for example an epoxy resin. After hardening, the bladder is deflated and removed. Finally, we drill the plug of hardened material which closes the secondary well so as to dig there a passage.

This technique is relatively complex and expensive, and very delicate to enforce.

Furthermore, it has already been proposed to line a well by means of a initially flexible tubular preform, radially deformable and expandable under the effect of an internal pressure, and curable in situ by hot polymerization of its wall.

This technique is described in particular in documents WO-94/21887, WO-94/25655 and FR-A-2 722 239.

The present invention proposes to transpose this known technique to lining the bifurcation zone in which the main borehole connects to the borehole secondary.

The objective of the invention is to propose a simple and inexpensive device expensive, light, easy to install, and allows to obtain a perfect seal of the junction in the bifurcation zone.

The device for lining a well bifurcation, in particular a oil well, which is the subject of the present invention comprises - like this is known per se - a flexible, radially deformable and expandable tubular preform under the effect of an internal pressure, and curable in situ by hot polymerization of its wall.

This device is remarkable in that said preform is formed of a straight main section and a secondary section also straight forming a acute angle with the main section and connecting to the latter in a leaktight manner a middle zone, provisional restraint means being provided which make it possible to initially maintain the secondary section in the radially folded state applied against the main section, the assembly then constituting a rectilinear preform, while after removal of said temporary restraint means, and under pressure internal the secondary section is detached from the main section, the assembly then constituting a preform in the general form of "y", (whose lower bar is in the extension of one of the upper branches).

• le dispositif comprend un outil dilatateur sous forme de vessie gonflable, à membrane souple et élastique, logée à l'intérieur de la préforme, et arrachable en fin d'opération ;
• à l'état dilaté chacun des tronçons a une section circulaire, le diamètre du tronçon principal étant plus grand que celui du tronçon secondaire, ou identique à celui-ci ;
• lesdits moyens de contention sont des liens annulaires frangibles entourant les tronçons principal et secondaire, aptes à se rompre les uns après les autres, au-delà d'un certain seuil de pression interne.

Furthermore, according to a certain number of additional, non-limiting characteristics of the invention:

• the device comprises a dilating tool in the form of an inflatable bladder, with a flexible and elastic membrane, housed inside the preform, and removable at the end of the operation;
• in the expanded state each of the sections has a circular section, the diameter of the main section being larger than that of the secondary section, or identical to the latter;
• said compression means are frangible annular links surrounding the main and secondary sections, capable of breaking one after the other, beyond a certain internal pressure threshold.

a) on fait descendre la préforme dans le puits alors qu'elle se trouve à l'état radialement rétracté et que le tronçon secondaire est appliqué contre le tronçon principal, l'ensemble ayant une configuration rectiligne ;

b) on positionne la préforme dans la zone de la bifurcation de telle manière que l'extrémité libre du tronçon secondaire se présente à l'entrée du forage secondaire en biais ;

c) on gonfle la préforme sous pression modérée (prégonflage) de manière à provoquer la rupture progressive des liens de contention et, corrélativement, le dépliement radial et le déploiement angulaire progressifs du tronçon secondaire, tout en continuant à faire descendre concomitamment la préforme ;

d) la portion bifurquante de la préforme étant sensiblement positionnée au niveau de la portion bifurquante du puits, on arrête le mouvement de descente ;

e) on gonfle la préforme par augmentation de la pression interne pour en provoquer l'expansion radiale et l'appliquer contre les parois du puits ;

f) la pression restant maintenue, on chauffe la préforme de manière à en polymériser la paroi ;

g) on dégonfle la vessie, et on la désolidarise de la préforme.

The method for sealingly lining a bifurcation of wells, in particular of oil wells comprising a main borehole and a secondary borehole at an angle, using a device as described above, is remarkable in that that, making use of a preform, the angle of which said main and secondary sections form between them is close to that of the bifurcation:

a) the preform is lowered into the well while it is in the radially retracted state and the secondary section is applied against the main section, the assembly having a rectilinear configuration;

b) the preform is positioned in the bifurcation zone in such a way that the free end of the secondary section is presented at the entry of the secondary drilling at an angle;

c) the preform is inflated under moderate pressure (pre-inflation) so as to cause the progressive rupture of the compression links and, correspondingly, the gradual radial unfolding and angular deployment of the secondary section, while continuing to lower the preform concomitantly;

d) the branching portion of the preform being substantially positioned at the branching portion of the well, the downward movement is stopped;

e) the preform is inflated by increasing the internal pressure to cause it to expand radially and apply it against the walls of the well;

f) the pressure remaining maintained, the preform is heated so as to polymerize the wall;

g) the bladder is deflated, and it is detached from the preform.

Other characteristics and advantages of the invention will become apparent from the description and attached drawings, which represent, by way of example not limiting an embodiment and a preferred embodiment.

• la figure 1 est une vue générale de la préforme dans son état initial, avant son introduction dans le puits ;
• les figures 2, 3 et 4 sont des vues similaires à la figure 1, représentant plusieurs étapes successives de déploiement de la préforme au cours de sa mise en place ;
• les figures 5A, 5B, 5C sont des sections de la préforme coupées par des plans transversaux référencés respectivement A-A à la figure 1, B-B à la figure 1 et C-C à la figure 4 ;
• la figure 6 est une vue générale schématique montrant en coupe longitudinale une bifurcation de puits, à l'intérieur de laquelle a été introduite une préforme destinée au chemisage de ladite bifurcation ;
• les figures 7 à 16 sont des vues analogues à la figure 6, à plus grande échelle, représentant les différentes étapes du chemisage, la préforme étant représentée coupée par un plan longitudinal sur les figures 11 à 16.

In these drawings:

• Figure 1 is a general view of the preform in its initial state, before its introduction into the well;
• Figures 2, 3 and 4 are views similar to Figure 1, showing several successive stages of deployment of the preform during its establishment;
• Figures 5A, 5B, 5C are sections of the preform cut by transverse planes referenced respectively AA in Figure 1, BB in Figure 1 and CC in Figure 4;
• Figure 6 is a general schematic view showing in longitudinal section a well bifurcation, inside which has been introduced a preform intended for lining said bifurcation;
• FIGS. 7 to 16 are views similar to FIG. 6, on a larger scale, showing the different stages of the lining, the preform being shown cut by a longitudinal plane in FIGS. 11 to 16.

In its normal state, which is that of FIG. 4, the preform, which constitutes the essential part of the device according to the invention, referenced 1, is a flexible preform, foldable longitudinally on itself to occupy space weak radial, and which can be put to the round first under the effect of a pressure internal moderately, then radially expanded under the effect of greater internal pressure.

This principle of expansion in two stages, namely unfolding followed by extension is described in particular in WO-94/25655 already cited (see FIG. 6A or 6B, 7 and 7 ').

According to the present invention, this preform 1 comprises a straight main section 10 and a secondary section 11 which forms an acute angle with the main section, and connects to it in its middle zone.

The preform therefore has the general appearance of an inverted "y", the bifurcation of which is directed downward, that is to say towards the bottom of the well.

We have designated by 10a the branch of the main section located on the side of the opening of the well and by 10b the other branch, facing the bottom of the well, this branch facing the secondary section 11.

As an indication, the branches 10a and 10b each have a length La , respectively Lb of between 3 and 5m, while the secondary section 11 has a length L of the order of 2 to 4m.

In the unfolded state, the tubular sections 10 and 11 have a shape cylindrical. As an indication, the main section 10 has an outside diameter of the order of 100mm and an inside diameter of around 50mm, while section 11 has a outer diameter between 80 and 100mm and an inner diameter between 30 and 50mm.

Of course, these diameters are directly related to the diameters of casings in the borehole.

The angle α is for example of the order of 30 °.

The preform 1, as well as the internal dilator tool, which will be described more far away, are attached, at the high end of the preform, to a tool 2 which is integral with the end of a cable, flexible tube or suitable tool 20 which emerges from the well by its opposite end, through the wellhead.

An apparatus located at the well head makes it possible to lower the tube 20 in the well, in order to bring the preform into the desired position, the tube cable or tool and tool 2 being removed at the end of the operation, as is well known.

The tubular preform 1 has a multilayer structure which, so general, includes an outer skin and an inner skin between which is confined a thermosetting resin, initially flexible and malleable.

In the absence of internal overpressure, it is possible to fold longitudinally part 10, to make it take a section in the general shape of a heart, such as illustrated in Figure 5A.

This shaping provides space for the section 11 which, by being also deformed, can be applied intimately against section 10b so that the two adjoining sections are part of a fictitious cylinder extending the section axially 10a (see Figures 1 and 5A).

The preform is kept in this folded and compressed state, using a series of regularly spaced annular compression links 3. These are for example fiberglass cables.

These links have an increasing tensile strength for example gradually from bottom to top, the lower link being able to break more easily than the neighbor link above, and so on, to the top link, which is proximity of the connection area 10c of the section 11 with the main section

In Figure 6, there is shown in section the bifurcation well that we wish to tub. This includes an often vertical main borehole 4, provided with a cylindrical metal casing 40, and a bias bore 5 also provided with casing metallic 50, surrounded by cement 51.

The junction zone of the two boreholes, designated 6, is surrounded by soil 60 or there is the problem of sealing to be ensured, given that the casings 40 and 50 do not are not related.

The device according to the invention comprises, mounted inside the preform 1, a dilator in the form of an inflatable bladder, with flexible membrane and elastic, inside which it is possible to introduce, either from the head of well, or by pumping the liquid present in the well, a pressurized fluid - by example of water or petroleum - the pressure of which can be varied, by controlling.

This type of preform / expansion tool assembly has already been described completely in WO-94/25655 already mentioned, to which reference may be made to need, and this is why it will not be described here again in detail, so as not unnecessarily weigh down the description.

With reference to FIG. 11, the membrane 7 has been designated by the reference 7 constituting the bladder, into which opens the tool 2, and which is closed at its low ends. The bladder has the shape of an inverted "y", complementary to its housing inside the preform.

The wall of the preform, made of thermosetting material, is referenced 8.

Returning to FIG. 6, which shows the start of the lining operation, we note that the preform 1, suspended from the tool 2 and the tube or tool cable 20, has been lowered into the well so that the free (closed) end 110 of the section secondary 11 is positioned in the bifurcation zone 6, substantially at the mouth secondary drilling 5.

The displacement of the preform in the well is easy because it has a straight configuration and has a small radial footprint.

We find this positioning in Figure 7.

By introducing a fluid under moderate pressure, not exceeding one determined limit value, inside the bladder / preform assembly, firstly, a pre-inflation of the preform, which has the effect of first of all causing breaking the lowest link 3 (the least resistant).

At the same time, we lower the preform a little more into the well.

As a result of the first link breaking, the lower end areas of the section 10b and section 11 take a cylindrical shape, and the part 11 tends to take off from part 10b, deploying laterally, to form an angle with the part 10b. This movement, associated with other means of orientation, allows it to orient itself substantially in the axis of secondary drilling 5 (see Figure 8).

We observe a successive rupture of the links 3, from the bottom to the top, which done concomitantly with the descent of the preform 1, the branch 10b descending vertically, co-axially, in the main borehole 4 while the section 11 penetrates axially inside the secondary borehole 5 (see FIG. 9).

When - as illustrated in FIG. 10 - the middle preform zone 10c has arrived in the bifurcation zone 6, the main 10 and secondary 11 sections of the preform being substantially aligned with the main holes 4 and respectively secondary 5, lower the preform. In this state, the preform is always subjected to a moderate pressure, designated P ₀ in FIG. 10.

The same situation is illustrated in Figure 11, which shows in section the expandable bladder / preform assembly.

The fluid pressure inside the bladder 7 is then increased, to a value P substantially greater than a P ₀ .

This produces swelling and progressive radial expansion, starting from of its median zone, of the entire preform, as illustrated in FIGS. 12, 13 and 14.

At the end of inflation, the upper and lower ends of the main section of the preforms are intimately applied against the casing 40; similarly, the area free end of the secondary section 11 is intimately applied against the casing 50.

The middle area of the preform is not necessarily in contact with the wall 60, but this does not matter.

Then, in a conventional manner as described in particular in WO-94/25655 already cited, to the hot polymerization of the preform. This can be done for example by introducing a hot liquid inside the preform, by reaction chemical, or by Joule effect, electrically conductive wires being embedded inside the preform wall and / or the membrane of the expansion tool.

At the end of the polymerization, the preform becomes rigid and the desired tubing, in the form of a perfectly sealed inverted "y" conduit ensuring the connection of the casings 40 and 50.

As illustrated in FIG. 15, the bladder 7 is then deflated by pumping the liquids which were there, then said bladder is torn off by removing the tool 2 and the bladder deflated adjoining it.

The liner in place is shown in Figure 16.

It should be noted that the drawings have not taken into account (artificially) the decrease in length of the preform sections, which results from their radial expansion, and which in practice is relatively large, this to facilitate the understanding of the different stages of the process.

The means of restraint could consist of a fabric sheath tear longitudinally, from bottom to top, surrounding the preform parts 10b and 11.

The internal pressures P ₀ and P are in fact differential pressures between the interior and exterior pressures of the preform.

As an indication, P ₀ is less than or equal to approximately 3 bars, while P is of the order of 30 bars.

Always for information, if the initial diameter - unfolded, but not expanded - of section 10 is of the order of 100mm, it is of the order of 160mm after expansion radial.

It goes without saying that the dimensions of each of the sections 10 and 11, as well as the value of the angle α, will be chosen according to the real conditions encountered on the land, in particular according to the diameter of the main and secondary drilling and the angle that these two holes form between them.

It would not go beyond the scope of the invention to provide a device whose the preform consists of a main section provided with two, or even more than two auxiliary sections.

In the same way, the device according to the invention can allow to seal and consolidate pipeline bifurcations.

Claims (5)

1. A device for lining a bifurcation in a well, in particular in an oil well, or in a pipe, characterized in that it includes a radially deformable flexible tubular preform that can be expanded by internal pressure and hardened in situ by heating its wall to polymerize it, said perform being formed of a rectilinear main section (10) and a rectilinear secondary section (11) at an acute angle (α) to the main section (10) and joined and sealed to the latter in a middle area (10c), temporary restraining means (3) being provided to hold the secondary section (11) initially in a radially folded condition, pressed against the main section (10), the combination then constituting a rectilinear preform, whereas after removal of said temporary restraining means, and due to internal pressure, the secondary section (11) separates from the main section (10), the combination then constituting a generally "y" shape preform.
2. A device according to claim 1 characterized in that it includes an expander tool in the form of an inflatable flexible and elastic membrane bag (7) housed inside the preform and adapted to be pulled out at the end of operation.
3. A device according to claim 1 or claim 2
   characterized in that in the expanded state each section (10, 11) has a circular cross-section, the diameter of the main section (10) being greater than or the same as that of the secondary section (11).
4. A device according to any one of claims 1 to 3
   characterized in that said restraining means (3) are breakable annular bindings around the main and secondary sections (10, 11) adapted to break one after the other beyond a particular internal pressure threshold.
5. A process for lining and sealing a bifurcation in a well, in particular in an oil well comprising a main bore (4) and an oblique secondary bore (5), by means of a device according to claim 2 in conjunction with claim 4, characterized in that, using a preform in which the angle (α) between said main section (10) and said secondary section (11) is close to that of the bifurcation:

   a) the preform is lowered into the well when in the radially retracted state and with the secondary section (11) pressed against the main section (10), the combination having a rectilinear configuration;

   b) the preform is positioned in the area of the bifurcation (6) so that the free end (110) of the secondary section (11) is at the entry of the oblique bore (5);

   c) the preform is inflated at moderate pressure (P₀) (pre-inflation) so as to rupture progressively the restraining bindings (3) and to cause progressive radial unfolding and angular deployment of the secondary section (11) concomitantly with further lowering of the preform;

   d) lowering is stopped when the bifurcate portion of the preform (10c) is substantially positioned at the level of the bifurcate portion (6) of the well;

   e) the preform is inflated by increasing its internal pressure (P) to cause it to expand radially and to press it against the walls of the well;

   f) with the pressure (P) maintained, the preform is heated to polymerize the wall;

   g) the bag (7) is deflated and separated from the preform.

Images