EP0122839B1 - Method and apparatus for conducting logging and/or work-over operations in a borehole - Google Patents

Description

The present invention relates to a method and a device making it possible to carry out measurements or / and interventions in a well at the level of the surrounding formations, and more particularly of formations subjected to hydraulic compression. The invention is particularly applicable when it is a question of carrying out measurements and / or interventions at the level of geological formations located in an area to be isolated from the rest of the well in which a hydraulic fluid under pressure is injected in order to fracture the training at this level (hydraulic fracturing process).

Prior hydraulic fracturing techniques are, for example, described in US Patent 3,427,652.

The measurements carried out by applying the present invention may for example include the triaxial recording of the noises produced by the rocks thus placed under stress. The analysis of the detected vibrations makes it possible to define the orientation of the noise source and consequently the direction of propagation of the fracture. This analysis technique is well known to geophysicists and will not be described here in more detail.

Techniques according to the prior art for determining the propagation of fractures in the soil are described, for example, in US Pat. Nos. 3,739,871 and 3,775,739.

The measurements carried out may also include recording the pressure and the background temperature, the measurement (focused or not) of the electrical resistivity of the formations, etc.

These measurements may be supplemented by viewing the walls of the well by television camera, for example.

One of the objects of the invention is to provide a device making it possible in particular to move a measuring or intervention instrument in a well zone possibly subjected to hydraulic compression, both during and at the end of the fracturing. hydraulic formations surrounding this area.

Already known from US-4 349 072 a device for performing measurements or / and interventions in a well, this device comprising a casing open at its lower end and with a diameter less than that of the well, an instrument measurement or intervention (probe), movable by remote control from the surface between a first position where said instrument is housed in the lower part of the casing forming a protective casing and a second position where said instrument leaves at least partially from said casing 'lower end thereof, to allow measurement or intervention and an electrical transmission cable equipped with a first electrical connection member adapted to be moved in the casing to be connected to a second connected electrical connection member audit instrument.

Also known from US Pat. No. 2,153,254 is a technique for carrying out tests for the production of fluids from geological formations traversed by a well, using casing provided at its lower part with a sealing member, or packer. , coming to bear against an area of the wall of the well having a conical shape.

These production tests include listening and recording on the surface of the noises created by the flow of fluids produced by geological formations.

The device according to the present invention makes it possible to carry out measurements or / and interventions in a well. It comprises a casing with a diameter smaller than that of the well, at least one measuring or intervention instrument, a base or probe support, and is characterized in that it comprises at least one sealing member surrounding said casing, a flexible connecting member connecting the base to the measuring instrument, said flexible connecting member comprising at least one electrical connection, and in that the base or probe support is normally arranged, in operation, at the inside the casing in the lower part thereof.

• a) on descend ledit ensemble dans le puits,
• b) on met en place ledit organe d'étanchéité,
• c) on ancre la sonde, l'ordre de mise en oeuvre de ces deux dernières étapes pouvant être inversé,
• d) on détend l'organe de liaison, et
• e) on effectue la fracturation.

The present invention also relates to a method for carrying out measurements or interventions in a well in which an assembly comprising a casing, at least one sealing member, a probe support or base, and a connecting member is introduced into the well. connecting said probe to said base. This method is characterized in that it comprises the following stages:

• a) the said assembly is lowered into the well,
• b) said sealing member is put in place,
• c) the probe is anchored, the order of implementation of these last two steps can be reversed,
• d) the link member is relaxed, and
• e) fracturing is carried out.

In addition, the devices according to the prior art are not suitable for carrying out measurements or interventions at the level of formations subjected to hydraulic compression.

This problem can be solved, according to the invention, by using a device of the type defined above in which said casing is surrounded by at least one expandable annular sealing member located at a level higher than said measuring or measuring instrument. intervention, when the casing is arranged vertically and said instrument placed in its first position, said annular sealing member having an axial passage traversed by a flexible connecting member comprising an electric cable connected to said instrument.

The prior devices also have the drawback of transmitting vibrations from the casing to the probe via the extension member which connects them, which risks greatly disturbing the measurements made by the probe, in particular when these are acoustic measurements.

This drawback is eliminated according to the invention, by applying a method for carrying out measurements or / and interventions in a well, in which at least one measuring or intervention instrument housed in a casing is introduced into the well, the lower part of the latter, and connected to an electrical connection member by a connecting cable, then a transmission cable is fitted into the casing equipped with an electrical connection member adapted to be connected to the previous one and we make take out, at least partially, said instrument from the casing, characterized in that said instrument is brought out in the extended position of said connecting cable, then the tension of said connecting cable is released by a limited relative movement of said instrument and said casing, before performing the measurement and / or intervention.

• - les figures 1 et 2 illustrent respectivement la position initiale et la position de travail d'un dispositif selon l'invention, descendu dans un puits traversant des formations géologiques,
• - les figures 3A et 3B montrent schématiquement en vue développée le système d'ancrage de l'élément-support tubulaire, respectivement dans la position de verrouillage de cet élément et au cours de son déverrouillage,
• - la figure 3C est une vue de détail du dispositif au voisinage de ce système d'ancrage,
• - les figures 4 à 8 illustrent les différentes phases de la mise en oeuvre du dispositif selon l'invention, et
• - les figures 9 et 10 illustrent schématiquement deux autres modes de réalisations du dispositif selon l'invention.

An exemplary embodiment of the invention is illustrated by the appended drawings where:

• FIGS. 1 and 2 respectively illustrate the initial position and the working position of a device according to the invention, lowered into a well passing through geological formations,
• FIGS. 3A and 3B schematically show in developed view the anchoring system of the tubular support element, respectively in the locking position of this element and during its unlocking,
• FIG. 3C is a detailed view of the device in the vicinity of this anchoring system,
• FIGS. 4 to 8 illustrate the different phases of the implementation of the device according to the invention, and
• - Figures 9 and 10 schematically illustrate two other embodiments of the device according to the invention.

FIGS. 1 and 2 correspond respectively to the initial position of the device according to the invention, lowered into a partially cased well 1 and to the working position of this device in which the probe 2 has come out of its protective casing 3.

The well 1 is fitted over a certain length with a casing 4 terminated by the shoe 5 at its lower part.

The device shown comprises at its lower part the protective casing 3 in which is housed at least partially the measuring or intervention instrument 2 and which is supernatant from a casing 6 to which this casing is connected.

It is considered in what follows, by way of example, that the instrument 2 is a logging probe, but it could also consist of a television camera, or an intervention instrument such as, for example , a perforation tool, etc ...

An annular sealing member 7, radially expandable, which may be of a conventional type (packer) is interposed between the casing 3 and the casing 6.

The radial expansion of this member is for example obtained by axial displacement of the casing 6, causing the spacing of the packer anchoring corners. We can also use a packer with hydraulic anchoring of a known type, for example the AD1 model from the company BAKER OIL TOOLS.

In its expansion position, this member 7 is pressed against the wall of the casing 4. The casing 3 and the casing 6 are both open at their ends.

A tubular support element 8 is housed in the casing 6, this tubular element being open at its upper part and comprising at its lower part a support piece or base 9 equipped with an anchoring system.

The probe 2 is connected to the base 9 by a flexible connection, that is to say of negligible stiffness which, in the illustrated embodiment, is formed by a support cable 13 passing through an axial passage 7a of the member 7 and of a length such that, in the upper position of the base 9 (FIG. 1), the probe 2 is housed, at least partially, inside its protective casing 3, while in the position bottom of the base 9, the probe 2 is removed from the casing 3 (working position shown in FIG. 2).

The cable 13 contains electrical conductors for supplying and transmitting the measurements which electrically connect the probe 2 to a male electrical plug 14, multi-contact, disposed on the base 9. This male plug is suitable for receiving a complementary female socket 15 surmounted by a load or ballast bar 16.

An anchoring system, either mechanical (for example shearable washers adapted to the socket 15 and cooperating with retaining members integral with the tube 8)) or electro-hydraulic (anchoring corners actuated by remote-controlled motor), provides a mechanical connection between the bar 16 and the base 9 when the electrical contact is made between the male plug 14 and the female socket 15.

The assembly formed by the socket 15 and the load bar 16 is fixed to the lower end of a cable 17 containing electrical conductors for supplying and transmitting the measurements made by the probe 2.

Examples of electrical connectors which can be used to constitute the whole of the male plug 14 and the female connector 15 are described in the invention patent 248471 and in the French patent application published EN 81/05306 "Electrical connector pluggable in a medium liquid ", filed on March 17, 1981.

The probe 2 could, for example be of a known type and include articulated anchoring arms 18, 19 folded along the probe body when this probe is housed in the protective casing (Fig. 1), these arms being deployed hydraulically by electric remote control from the surface, via cables 17 and 13, when the probe 2 came out of the casing 3, in the working position shown in FIG. 2, the arms 18 and 19 then anchoring in the wall of the well and pressing the probe 2 against this wall on the diametrically opposite side (Fig. 2) .

These arms may be connected to one or more pads applying against the wall of the well.

In an example of application where the probe 2 is used to detect and record acoustic signals produced by geological formations cracked by hydraulic fracturing, this probe could notably include triaxial dynamic accelerometers 20, recording the components A _x , Ay and A _z of the noise along three axes perpendicular to each other. This noise includes compression waves and shear waves. This probe may also include a hydrophone recording the compression waves of the fluid contained in the hole and pressure sensors 21 and 22 measuring respectively the hydrostatic pressure prevailing in the well outside the probe and the pressure of application of the arms 18 and 19 against the wall.

• - son inclinaison sur la verticale ainsi que l'angle formé par une génératrice repère de cette sonde avec le plan vertical passant par l'axe de la sonde ("tool face") cela au moyen d'accéléromètres statiques triaxiaux ou des inclinomètres,
• - l'orientation de la sonde par rapport au nord Magnétique, c'est-à-dire l'angle que fait le plan vertical passant par l'axe de la sonde avec le plan vertical contenant le nord Magnétique (au moyen de magnétomètres triaxiaux ou d'une boussole).

This probe may also include sensors determining in known manner:

• - its inclination on the vertical as well as the angle formed by a reference generator of this probe with the vertical plane passing through the axis of the probe ("tool face"), this by means of triaxial static accelerometers or inclinometers,
• - the orientation of the probe relative to Magnetic north, i.e. the angle made by the vertical plane passing through the axis of the probe with the vertical plane containing Magnetic north (by means of triaxial magnetometers or a compass).

When the probe is almost vertical, we only consider the angle between the vertical plane containing the axis of the probe and the reference generator and the vertical plane containing north Magnetic using dynamic triaxial magnetometers or a compass.

In the above example, the base 9 of the tubular support element 8 is provided with a fully mechanical anchoring system including a groove 10 cooperating with retaining lugs 10a. This system makes it possible to hold the tubular element in a first position, represented on FIG. 1, where the lower part of the base 9 is below the upper stop which can be formed by a first internal shoulder 11 of the casing 6 (FIG. .3C) at a sufficient distance from it so that the anchoring system can be unlocked by lifting the base 9 (see below).

When the groove 10 is released from the retaining lugs 10a the tubular support element 8 is placed in the low position under the effect of gravity, its base 9 then resting on a low stop formed by a second internal shoulder 12 of the casing 6 .

The base 9 as well as the internal shoulders 11 and 12 have recesses or bores allowing a hydraulic fluid to flow throughout the casing 6, around the tubular support 8, in the two positions of the probe 2.

As shown schematically in Figures 3A and 3B, the anchoring system 10 may include a W-shaped groove formed in the outer wall of the base 9 of the tubular support element 8, this base 9 can rotate around d a vertical axis with respect to the casing 6. In the high position shown in FIGS. 3A and 3C, the upper edge of the top of this groove is supported by a lug 10a secured to the internal wall of the casing 6.

By slightly lifting the assembly 16-15-14-8-9 by a pull F, exerted on the cable 17 from the position shown in FIG. 3A, the notch 10b at the upper part of the groove 10 is released of lug 10a. The upper edge 10c of the groove 10 then rests on this lug, causing a rotation of the base 9 which brings the upper edge 10d of the groove 10 opposite the lug. By releasing the traction F, the edge 10d comes to bear on the lug 10a, causing the rotation of the base 9 until its release from the lug 10a through the opening 10e (FIG. 3B). The above-mentioned assembly then descends by gravity to its low position shown in FIG. 2. Instead of the fully mechanical anchoring system described above, the base 9 could include an electro-hydraulic anchoring system remotely controlled from the area.

The implementation of this device is indicated below with reference to Figures 4 to 8 which show the successive stages of this technique. FIG. 4 illustrates the first step in which the fastening of the packer 7 to the lower end of the casing 6 is first carried out on the surface. The tubular support element 8 is then introduced into the latter, arranged vertically. 'we place in the high position (Fig. 1), the base 9 resting on the lugs 10a via the anchoring groove 10, by passing through the pacher 7 the electrical cable 13 previously connected to the base 9 .

The probe (or intervention tool) 2 is then fixed under the packer 7 at the lower end of the cable 13 and is thus suspended from the lugs 10a in its high position in FIG. 1. One then fixes at the lower end from packer 7 the protective housing of the probe which is housed inside the housing. The assembly is then gradually lowered into the well 1 (Fig. 4) from the drilling tower 23, by adding successive casing elements 6 until the probe 2 reaches the desired depth, substantially at the level of the shoe 5 , the number of casing elements 6 connected end to end making it possible to know at all times the depth reached. When this position is reached, the packer 7 is anchored to the lower end of the casing 4 (Fig. 5).

The casing 6 is connected at its upper part to a pipe 24 for supplying pressurized hydraulic fluid and is provided at its top with a safety shutter or cable gland 25 in which the cable 17 supporting the assembly is made to slide formed by the load bar 16 and the female socket 15, until the latter comes to be connected to the male plug 14 fixed on the base 9 of the tubular element 8 which supports the probe, the tubular support element 8 ensuring guidance of the assembly 15-16 to facilitate this connection.

Interlocking or mechanical connection members 15a and 8a are respectively adapted to the socket 15 and to the internal wall of the tube 8, these members being adapted to be released from one another by a sufficient tration exerted on the cable 17 from the surface.

In the example considered, the members 15a and 8a consist respectively of a shearable washer carried by the socket 15 or the load bar 16 and of arms or knives retaining this washer, carried by the tubular support element 8.

The cable 17 is unwound from the surface from a winch 26. Between the winch 26 and the shutter 25, the cable 17 passes over the return pulleys 27 and 28 (Fig. 6).

When the electrical connection operation of the socket 15 to the plug 14 as well as the mechanical connection between the bar 16 and the base 9 are carried out, a slight traction F exerted on the cable 17 (FIG. 3B) makes it possible to dissociate from the lug 10a the base 9 of the tubular element 8 which then passes into the low position corresponding to FIG. 2, the probe 2 having come out of its protective casing 3 and being then in the uncovered or uncovered lower part of the well 1 (Fig. 7).

The support tube 8 of the probe 2 is then slightly raised and consequently this probe itself from a height h (insufficient to make it enter its casing 3) by a traction exerted on the cable 17 and, in this position of the probe (Fig. 8), the opening of the articulated arms 18 and 19 is remote controlled from the station 29, via the cables 17 and 13, the ends of these arms being anchored in the wall of the well 1 , by pressing the probe 2 against the portion of wall diametrically opposite to these arms.

The traction exerted on the cable 17 at the surface is released and the support tube 8 then falls back into its low position under the effect of gravity. This has the effect of giving some slack to the cable 13 thus relaxed (FIG. 8).

Under these conditions, measurements or operations can now be carried out using the probe or the instrument 2 without transmitting the vibrations of the casing 6 to this probe or instrument.

The device according to the invention therefore comprises means making it possible to remove said instrument 2 from the vibrations of said casing 6 during measurement or intervention. These means are constituted by the combination of anchoring members 18, 19 of said instrument 2 at a fixed level of the well 1, the latter being actuated by remote control, and of a flexible connection 13 between said instrument 2 and a support part. 9 movable in the casing 6 between a position close to the upper stop 11 and a lower stop position 12 which respectively define a first and a second position of said instrument 2.

The remote control signals of the probe 2 from the surface, as well as the measurement signals coming from the probe 2 and the electric current supplying it, are respectively transmitted from and to the surface station 29 via the incorporated conductors to cables 13 and 17, the electrical connection between these conductors and the station 29 being produced in a known manner by a set of brushes rubbing on slip rings integral with the winch shaft 26.

The hydraulic fracturing of the formations located under the packer 7 can be carried out by pumping hydraulic fluid under pressure through the pipe 24 located on the surface.

When the various operations or measurements are completed, the closing of the articulated arms 18 and 19 is remote controlled from the surface, the probe 2 is returned to its protective casing by pulling on the cable 17 replacing the base 9 of the support tube 8 in the position high of Figure 1 where this base 9 is supported by the lug 10a. We can then slowly decompress the geological formations by reducing the pressure in line 24.

The engagement of the groove 10 and the lugs 10a takes place in a manner analogous to the clearance described above with reference to FIGS. 3A and 3B.

Sufficient traction on the cable 17 shears the washer 15a and then disconnects the female electrical socket 15 from the male plug 14, the base 9 coming to bear against the high stop 11, and it is possible to go up by means of the cable 17 '. assembly constituted by the socket 15 and the load bar 16 surmounting this socket.

The assembly 8, 9, 13, 12 remains suspended from the retaining lugs 10a integral with the casing 6, by means of the anchoring system in W designated by the reference 10.

The casing 6 can then in turn be gradually withdrawn from the well, the elements of this casing being successively disconnected at the surface.

We have described above by way of example, an embodiment according to which the annular sealing member 7 is disposed under the base 9. This embodiment has the advantage of having the member 7 in the immediate vicinity of shoe 5 and to limit the length of the overhang between the base of this shoe and the bottom.

• - l'ensemble mécanique situé sous le packer 7 est en équipression avec le fluide hydraulique comprimé au-dessous de ce packer,
• - il est possible de ménager dans le tubage 6 des ouvertures d'écoulement du fluide, au-dessous du niveau de l'organe 7, entre celui-ci et le niveau de la butée haute 11.

It would not, however, depart from the scope of the invention to place all of the equipment 8, 9 at a level lower than that of the sealing member 7, the axial passage of which would then be crossed by the transmission cable. 17. This last embodiment has the following advantages:

• the mechanical assembly located under the packer 7 is under pressure with the hydraulic fluid compressed below this packer,
• - It is possible to provide in the casing 6 fluid flow openings, below the level of the member 7, between the latter and the level of the upper stop 11.

Furthermore, other modes of implementing the equipment defined above can also be envisaged.

It will, for example, be possible to place the sealing member 7 in a non-cased area of the well which will be isolated from the rest of the well by the use of a sealing member completely sealing the well at a level below that of the instrument or probe in its low position.

According to a variant of this latter embodiment, the casing 4 descends under the total sealing member defined above. In the zone delimited by the two sealing members, the casing 4 is perforated in a conventional manner, in order to allow the injected hydraulic fluid to flow through the formations located at this level.

When the entire device is under hydraulic pressure, it is possible to move the instrument or probe 2 by simply pulling the cable 17 from the surface, after having remote-controlled the closure of the arms 18 and 19.

When the technique described above is applied to very deviated or horizontal wells, the instrument or probe 2 can be removed from the casing 3 by pumping hydraulic fluid followed possibly by a displacement of the casing 6 from the surface, in order to release the tension in the cable 13 before performing the measurement or intervention using the probe or instrument 2.

It would not go beyond the scope of the invention to have several probes or measurement or intervention instruments suspended from one another under the support piece 9.

According to another embodiment of the invention, shown in FIG. 9, the probe 31 is located in an area 32 of the well in which the fracturing will not be carried out. The fracturing is carried out in a zone 33 delimited by two sealing members 34 and 35 which, in the example of FIG. 9, are supported by the casing 36.

This tubing 36 carries a probe support 37, or base, comprising a possibly male connector 38 which will cooperate with a complementary connector like that shown in FIGS. 1, 2 or 3.

The probe support 37 is connected to the probe 31 by means of a flexible mechanical connection member 39 comprising at least one electrical connection.

The casing 36 has at least one opening 40 located between the two sealing members 34 and 35. It is through this opening that the fluid will be introduced to fraturate the area of the well designated by the reference 33.

If the sealing members are of the type with hydraulic anchoring, the opening 40 may be closed off firstly by a jacket 41 to allow the establishment of the sealing members, then this jacket will be moved using a cable technique. ("Wireline" in Anglo-Saxon terms) to free the opening 40 and allow the fracturing of the zone to be fractured 33.

It is obvious that at least during the fracturing time, the probe support 37 is sealed and prevents any flow of the fracturing fluid towards the zone 32 where the measurements or interventions are carried out.

• - l'ensemble constitué par le tubage 36, les organes d'étanchéité 34 et 35, le support de sonde 37, l'organe de liaison souple 39 et la sonde 31, est descendu dans un puits. L'inclinaison du puits est telle que, lorsque la sonde 31 est soumise aux forces de gravité, elle maintient l'organe de liaison souple tendu.
• - la sonde est ancrée dans le puits à l'aide de bras 42 et 43.
• - le tubage est descendu dans le puits d'une hauteur, qualifiée de hauteur de détente, suffisante pour détendre l'organe de liaison 39 sans pour autant rencontrer la sonde 31. Bien entendu, la sonde peut être ancrée dans le puits à une position telle, et la hauteur de détente peut être telle que la fracturation ait lieu dans une zone prédéterminée du puits.
• - les organes d'étanchéité sont mis en place, et
• - l'opération de fracturation peut commencer.

The implementation of the device described above is carried out as follows:

• - The assembly constituted by the casing 36, the sealing members 34 and 35, the probe support 37, the flexible connecting member 39 and the probe 31, is lowered into a well. The inclination of the well is such that, when the probe 31 is subjected to the forces of gravity, it keeps the flexible connecting member taut.
• - the probe is anchored in the well using arms 42 and 43.
• - The casing is lowered into the well by a height, qualified as a relaxation height, sufficient to relax the connecting member 39 without however meeting the probe 31. Of course, the probe can be anchored in the well at a position such, and the expansion height can be such that the fracturing takes place in a predetermined area of the well.
• - the sealing members are put in place, and
• - the fracturing operation can begin.

According to this embodiment of the invention, there is a system substantially balanced in pressure, since the pressure forces of the fracturing fluid are exerted on the two sealing members in opposite directions and therefore, the casing n is not subjected to a vertical force due to the pressure forces of the fracturing fluid.

FIG. 10 also represents an embodiment for which the measurements are carried out in an area of the well 44 which will not be fractured.

The fracturing will take place in a fracturing zone 45 delimited by at least two sealing members 46 and 47.

This embodiment differs from that shown in FIG. 9 in that the flexible connecting member 48 is fixed to a probe support, or base, 49 movable in the casing 50. The movement of the base 49 is limited by at least one lower stop 51. In this position, the base 49 prevents any flow of the fracturing fluid towards the zone of the well 44 where the measurements are made.

This embodiment allows the probe 52 to be moved even after the organs have been anchored sealing 46 and 47.

According to this embodiment, it is also possible to move the probe during fracturing. In this case, it will be necessary for the latching or mechanical connection members to allow the transmission of a sufficient tensile force to overcome the action of the pressure forces on the base 49. Similarly, the base 49 must remain watertight during of this displacement.

Of course, in this case, the passage opening 53 of the fracturing fluid may be placed closer to the upper sealing member 47, just as the lower stop 51 may be placed in a lower position relative to the sealing member 46.

• a) on descend l'ensemble comportant le tubage 50, la base 49, l'organe de liaison souple 48, la sonde 52 et les organes d'étanchéité 46 et 47,
• b) les organes d'étanchéité sont mis en place éventuellement lorsque la base 49 est en position basse,
• c) on descend depuis la surface un connecteur 55 relié à un câble 54, ledit connecteur venant coopérer avec la base 49 de manière à assurer une liaison électrique et mécanique,
• d) on ancre la sonde 52 alors que la base 49 n'est pas en contact avec la butée 51,
• e) on descend la base 49 grâce au câble 54 relié à la surface jusqu'à ce qu'elle rencontre la butée 51, de manière à détendre l'organe de liaison souple 48, et
• f) on effectue la fracturation.

An example of implementation of this embodiment is given below:

• a) the assembly comprising the casing 50, the base 49, the flexible connection member 48, the probe 52 and the sealing members 46 and 47 are lowered,
• b) the sealing members are optionally put in place when the base 49 is in the low position,
• c) a connector 55 is lowered from the surface connected to a cable 54, said connector coming to cooperate with the base 49 so as to provide an electrical and mechanical connection,
• d) the probe 52 is anchored while the base 49 is not in contact with the stop 51,
• e) the base 49 is lowered by the cable 54 connected to the surface until it meets the stop 51, so as to relax the flexible connecting member 48, and
• f) fracturing is carried out.

Step b) can be carried out before step c) or after step d).

Claims (10)

1. A device making it possible to carry out measurements and/or interventions in a well comprising a tubing (6, 36) of a diameter less than that of the well, at least one measuring or intervention instrument (2, 31), a sensor support or base (9, 37), characterised in that it comprises at least one sealing element (7, 34) surrounding said tubing, a flexible connecting element (13, 39) connecting the sensor support or base (9, 37) to the measuring or intervention instrument (2, 31), said flexible connecting element (13, 39) comprising at least one electrical connection, and in that the sensor support or base (9, 37) is normally disposed inside the tubing (6, 36) in the lower part of the latter during the working phase.

2. A device as in claim 1, making it possible to carry out measurements and/or interventions in a well in a zone of this well subject to hydraulic compression, comprising a tubing (6) open at its lower end and of a diameter less than that of the well, at least one measuring or intervention instrument (2), displaceable from the surface between a first position in which said instrument . is housed in the lower part of the tubing forming a protective casing (3) and a second position in which said instrument (2) emerges at least partially from said tubing (6) at the lower end (3) of the latter to permit the measurement or the intervention, and an electrical transmission cable (17) fitted with a first electrical connecting element (15) adapted to be displaced in the tubing (6) to connect to a second electrical connecting element (14) connected to said instrument (2), characterised in that said sealing element surrounds the tubing (6) in its lower part and comprises at least one annular sealing element (7) exhibiting an axial passage (7a) through which a flexible connecting element (13) passes comprising an electrical connecting element connected to said measuring instrument (2).

3. A device as in claim 2, in which the sensor support or base (9) is connected to said instrument (2) by an electrical connecting cable (13), this sensor support or base (9) being displaceable in the tubing (6) between two positions corresponding respectively to said first and to said second position of said instrument (2) and means for holding said sensor support or base (9) in its first position, these means being unlockable by simply pulling on said electrical transmission cable (17), characterised in that said sensor support or base (9) and said instrument (2) are disposed on either side of said annular sealing element (7), said electrical connecting cable (13) passing through said axial passage (7a) of this element (7).

4. A device as in claim 2, in which the sensor support or base (9) is connected to said instrument (2) by an electrical connecting cable (13), this sensor support or base (9) being displaceable in the tubing (6) between two positions corrosponding respectively to said first and to said second position of said instrument (2) and means for holding said sensor support or base (9) in its first position, these means being unlockable by simply pulling on said electrical transmission cable (17), characterised in that said sensor support or base (9) and said instrument (2) are both disposed below said annular sealing element (7) the axial passage (7a) of which has said electrical transmission cable (17) passing through it.

5. A device as in any one of the preceding claims, characterised in that it comprises means making it possible to protect said instrument (2) from the vibration of said tubing (6) during the measurement or intervention, these means being constituted by elements (18, 19) for anchoring said instrument (2) at a fixed level in the well (1), these elements being operated by remote control, and a flexible connection (13) between said instrument (2) and a sensor support or base (9) displaceable in the tubing (6) between said first and said second position of said instrument (2).

6. A device as in claim 5, characterised in that said connection is constituted by a flexible electrical cable (13).

7. A device as in claim 5, characterised in that said instrument (2) is a sensor adapted to detect acoustic signals produced by the cracked formations.

8. A device as in claim 1, characterised in that it comprises at least two sealing elements (34, 35 or 46, 47) delimiting the zone of the well to be fractured.

9. A method for carrying out measurements or interventions in a well in which an assembly comprising a tubing, at least one sealing element, a sensor support or base and a connecting element connecting said sensor to said base is introduced into the well, characterised in that it comprises the following stages:

a) said assembly is lowered into the well,

b) said sealing element is put in position,

c) the sensor is anchored - the order of these last two stages can be reversed,

d) the connecting element is extended and

e) the fracturing is carried out.

10. A method as in claim 9 for carrying out measurements and/or interventions in a well in which a measuring and/or intervention instrument housed in a tubing in the lower part of the latter and connected to an electrical connecting element by a connecting cable is introduced into the well, then a transmission cable fitted with an electrical connecting element adapted to connect to the preceding connecting element is introduced into the tubing and said instrument is moved at least partially out of the tubing, characterised in that said instrument is moved out in the extended position of said connecting cable, then the tension of said connecting cable is relaxed by a limited relative movement of said instrument and said tubing before carrying out the measurement and/or the intervention.

Images