EP0296207B1 - Method and device for taking measurements and/or carrying out interventions in a well subjected to a hydraulic compression - Google Patents

Abstract

Method and device for taking measurements and/or carrying out interventions in a well comprising a first zone where a hydraulic compression, such as a hydraulic fracturation is achieved, and a second zone wherein are taken measurements and/or are carried out interventions, said compression zone communicating through a pipe (6) to hydraulic pressure means, the lower end of the pipe (6) comprising an assembly of one or a plurality of measuring instruments connected to the surface via a cable (17) placed inside the pipe (6) and mechanically uncoupled from the pipe by an elastic link, such as a linking cable (13). The method is particularly characterized in that at a pipe point adjacent to the fracturation zone, any fracturation fluid flow coming from or going to said fracturation zone is controlled by control means (12a, 12b) controlled at least partially by said cable (17) from the surface, said control means being situated at a level higher than the assembly. The device is particularly characterized in that it comprises means (12a, 12b) which control the fluid circulation between the pipe (6) and the compression zone (1a) and in that said cable is adapted to control said means (12a, 12b) from the surface. The invention applies particularly to measurements and/or interventions executed during the hydraulic fracturation of wells drilled into the ground.

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 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 a first zone to be isolated from the rest of the well, while a hydraulic fluid under pressure is injected in a second zone, so as to fracture the formations (hydraulic fracturing process).

Previous hydraulic fracturing techniques are, for example, described in US Pat. No. 3,427,652.

The measurements made 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 ground are described, for example, in patents US-3,739,871 and 3,775,739.

Measurements may also include recording pressure and background temperature, measurement (focused or not) of the electrical resistivity of formations, listening to and recording the noises created by the flow of fluids produced by geological formations.

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 and a method making it possible to prevent leaks of fluid, coming from the casing under pressure and supplying a well area subjected to hydraulic compression, influencing the measurements that the 'One performs in particular in said compression zone.

In one embodiment, the invention makes it possible in particular to move a set of one or more measuring or intervention instruments, in particular in the well zone subjected to compression in order to put them there.

The invention also makes it possible to protect from external mechanical actions a set of instruments placed at the lower end of the casing, during the descent of this set into the well towards the compression zone.

In another embodiment, the invention makes it possible to have a well hydraulically isolated compression zone in which measurements can be made and to have another uncompressed zone, outside and below this, in which measurements are made measures or / and interventions.

We know in patent FR-2.544.013 a device and a method for performing measurements and / or interventions in a well, or in a well area subjected to hydraulic compression.

However, this prior solution which makes it possible to place a set of instruments before or during a hydraulic compression and which ensures the protection of the set of instruments during its installation, is in particular sensitive to fluid leaks in the casing .

We know in patent FR-A-2,564,894 a device and a method making it possible to carry out measurements or / and interventions in a zone, a second zone being subjected to a hydraulic compression, however this previous solution does not allow to confuse the measurement or intervention zone with the hydraulic fracturing zone. In addition, this solution does not allow movement of the probe without putting the two zones in communication.

The measurements and / or interventions are carried out using a set of instruments connected to the surface by a cable.

The invention provides a device making it possible to carry out measurements or / and interventions in a well in which hydraulic compression, such as hydraulic fracturing, is carried out in a first zone and in which measurements and / or are carried out in a second zone. interventions.

The device comprises a casing with a diameter smaller than that of the well, an orifice for the passage of the compression fluid to the hydraulic compression zone, a set of one or more instruments fixed to an elastic connection cable connected to a control, connected to the surface by a cable. Said member comprises a support and means for anchoring said support to the casing, said set of instruments being adapted to be mechanically decoupled from the casing by means of the control member.

The support of the control member comprises a closure element, and the casing comprises a seat for cooperating with said closure element. Said cooperation is obtained after the anchoring of the support of said casing. The device is characterized in that said closure element controls the flow of said fluid through said passage orifice.

US-A-4,553,599 discloses an apparatus making it possible to control a flow in a tubing for petroleum production by means of a cable connected to the surface. However, this prior technique does not allow us to descend measurement or intervention probes into a well.

The device can be characterized in that it can comprise a casing, two annular sealing members cooperating with said casing and the wall of the well to delimit said compression zone, a set of at least one instrument connected by an elastic connection to a shaft secured to a base connected to the surface by a cable. Said shaft being movable in translation and being able to cooperate with isolation means integral with the casing to prevent the fluid contained in the casing from escaping from it through the lower end of this casing. It may also include a control member located in the vicinity of the lower part of the casing.

The device according to the invention can be used when said first compression zone is merged with said second measurement and / or intervention zone, and is characterized in that it can comprise an expandable annular sealing member surrounding the casing at its lower part.

The device can be characterized in that said casing can comprise at its lower end a protective casing in which can be housed said set of instruments and said device can include a control member allowing the fluid to flow through said member when a traction controlled is exerted on said cable and in that said device may comprise a support piece or base movable in the casing placed on said traction cable and adapted to hold said assembly in said casing, when it is in a first position, and making it possible on the one hand to exit the casing and move said casing away from the casing, and on the other hand to prevent any circulation of fluid between the casing and said compression zone, when said support piece is in a second position.

The device can also be characterized in that the assembly by means of the cable can comprise at least one electrical line, between the connection member equipping the end of said cable, and a complementary connection member secured to the base, said assembly being adapted to cooperate to achieve electrical continuity of the electrical line (s) between the cable and the set of instruments and / or to said control member.

The device can be characterized in that the base or support piece may include retaining means, such as an anchoring system adapted to cooperate with retaining members integral with said base, said means holding said base in a first position where said base is spaced from the lower end of the casing, and in that these means can be unlocked by means of the cable connected to the surface. The device can also be characterized in that the displacement of said base in one or the other of the two positions produces an opening or a closing of said control member and possibly produces the displacement of said set of instruments relative to said casing.

The device can be characterized in that said control member is electric and in that it can be adapted to be controlled by means of the cable connected to the surface.

The invention also provides a method for performing measurements and / or interventions in a well using the device. This method is characterized in that one controls the element obturation by means of said cable and / or differential pressure on either side of said passage orifice.

When said first compression zone and said second measurement and / or intervention zone are combined and arranged at the lower end of the casing, the method can be characterized in that when a controlled traction is produced on said obturation element by means of said cable, the circulation of fluid is allowed through said member.

In this same case, it can be characterized in that when a controlled traction is produced on said closure element via said cable, any circulation of fluid is prevented through said member.

The method can also maintain said control member in a position preventing any circulation of fluid by producing a controlled pressure difference between said casing and said zone to be fractured, either on either side of said passage orifice.

The method can be characterized in that by means of said cable, said set of instruments can be moved relative to said casing.

• a) on place ledit tubage dans ledit puits,
• b) on ancre ledit ensemble d'instruments à ladite zone de mesure ou/et intervention du puits,
• c) on assure la détente de la liaison élastique,
• d) on produit une pression hydraulique dans ladite zone de compression, et
• e) on obture ledit orifice de passage au moyen de l'organe d'obturation.

The invention also provides a method which can include the following steps for carrying out said measurements and / or interventions:

• a) placing said tubing in said well,
• b) anchoring said set of instruments to said measurement zone and / or intervention of the well,
• c) the elastic connection is relaxed,
• d) a hydraulic pressure is produced in said compression zone, and
• e) closing said passage orifice by means of the shutter member.

• f) on place ledit tubage dans ledit puits,
• g) on fait coulisser ledit ensemble dans ledit tubage,
• h) on ancre ledit ensemble d'instruments dans le puits au niveau de la zone à fracturer,
• i) on assure la détente du câble de liaison,
• j) on produit une pression hydraulique dans ladite zone de fracturation de manière à assurer la fracturation, et
• k) on obture ledit organe de contrôle.

This method in which said obturation element can allow any circulation of fluid when a controlled traction is exerted on said cable connected to the surface and where the seat has a section sufficient to allow said set of instruments to pass through it, may include the following steps:

• f) placing said tubing in said well,
• g) sliding said assembly in said casing,
• h) anchoring said set of instruments in the well at the level of the zone to be fractured,
• i) the connection cable is relaxed,
• j) hydraulic pressure is produced in said fracturing zone so as to ensure fracturing, and
• k) closing said control member.

• l) on équipe ledit ensemble d'instruments d'une fiche électrique de raccordement enfichable en milieu liquide,
• m) on place ledit ensemble à l'extrémité du tubage et on place ledit organe de connexion dans une position permettant la connexion avec un organe complémentaire relié au câble relié à la surface et provenant de l'extrémité supérieure du tubage, puis
• n) on introduit dans le tubage un câble de transmission équipé dudit organe complémentaire de connexion électrique adapté à venir se raccorder audit organe de connexion relié audit ensemble d'instruments.

The method, in which said set of instruments can be connected by said electrical connection to an electrical connection member and in which said cable connected to the surface can comprise at least one transmission line, can be characterized in that it comprises the following steps:

• l) equipping said set of instruments with an electrical plug for plugging in in a liquid medium,
• m) placing said assembly at the end of the casing and placing said connection member in a position allowing connection with a complementary member connected to the cable connected to the surface and coming from the upper end of the casing, then
• n) a transmission cable fitted with said complementary electrical connection member adapted to be connected to said connection member connected to said set of instruments is introduced into the casing.

• les figures 1 et 2 illustrent respectivement la position initiale et une position de travail d'un dispositif selon l'invention, descendu dans un puits traversant des formation géologiques,
• les figures 3A et 38 montrent schématiquement en vue développée le système d'ancrage de la pièce-support, respectivement dans la position de verrouillage de cette pièce et au cours de son déverrouillage,
• la figure 3C est une vue en détail du dispositif au voisinage de l'organe de contrôle de la circulation de fluides entre le tubage et la zone de compression,
• les figures 4 à 8 illustrent les différentes phases de la mise en oeuvre du dispositif selon l'invention,
• les figures 9 et 10 illustrent un autre mode de réalisation du dispositif selon l'invention utilisé lorsque l'on veut effectuer une compression hydraulique dans une zone d'un puits et les mesures ou/et interventions dans une autre zone.

The present invention will be clearly understood and its advantages will appear clearly on reading the description which follows, illustrated by the appended figures in which:

• FIGS. 1 and 2 respectively illustrate the initial position and a working position of a device according to the invention, lowered into a well passing through geological formations,
• FIGS. 3A and 38 schematically show in developed view the anchoring system of the support part, respectively in the locking position of this part and during its unlocking,
• FIG. 3C is a detailed view of the device in the vicinity of the member for controlling the circulation of fluids between the casing and the compression zone,
• FIGS. 4 to 8 illustrate the different phases of the implementation of the device according to the invention,
• Figures 9 and 10 illustrate another embodiment of the device according to the invention used when one wants to perform hydraulic compression in one area of a well and measurements or / and interventions in another area.

FIGS. 1 and 2 correspond respectively to the initial position of a 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 is removed from 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 set of measuring or intervention instruments 2 and which is surmounted by a casing 6 to which this casing is connected.

It is considered in what follows, by way of example, that the set of one or more instruments 2 comprises a logging probe, but it could also include a television camera, or an intervention instrument such as, for example, example, a punching 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. Any suitable safety means well known to those skilled in the art may be used during the installation of the sealing member 7, so that a blocking of this member 7 does not harm the ascent of the set of instruments 2.

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 centering guide 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 8a.

The set of instruments 2 is connected to the base 9 by a flexible elastic connection, that is to say of negligible stiffness which, in the illustrated embodiment, includes a connection cable 13 passing through an axial passage 7a of the member 7 and of length such that, in the high 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).

In this way, the set of instruments 2 is mechanically decoupled from the casing and the vibrations of the casing 4 are not transmitted to the set of instruments.

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 comprising for example shearable washers adapted to the socket 15 and cooperating with retaining members integral with the tube 8, or electro-hydraulic (comprising for example 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 traction cable 17 containing electrical conductors for supplying and transmitting the measurements made by the probe 2. This cable can in addition enclose conductors ensuring the control of certain members, such as the retaining one when the latter is electro-hydraulic, or ensuring the transmission provided by different sensors.

Examples of electrical connectors which can be used to constitute the assembly of the male plug 14 and the female socket 15 are described in US Pat. No. 4,500,155.

The probe could, for example, be of known type and include as anchoring means articulated anchoring arms 18, 19 folded along the body of the probe when this probe is housed in the protective casing (FIG. 1), these arms being deployed hydraulically by electric remote control from the surface, by means of cables 17 and 13, when the probe 2 has come out of the casing 3, in the working position shown in FIG. 2, the arms 18 and 19 are anchoring then 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 application where probe 2 is used to detect and record acoustic signals produced by geological formations cracked by hydraulic fracturing, this probe could in particular include triaxial dynamic accelerometers 20, recording the components A _x , A _y and A _z of the noise along three axes perpendicular to each other.

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 sonne 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 to 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 with respect to magnetic north, i.e. the angle made by the vertical plane passing through the axis of the sound with the vertical plane containing magnetic north (by means of triaxial magnetometers or of 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 magnetic north using dynamic triaxial magnetometers, or a compass.

In the above example, the base or support part 9 comprising a centering guide 8 is provided with entirely mechanical retaining means comprising a groove 10 cooperating with these retaining lugs 10a. This system makes it possible to maintain the support piece in a first position, shown in Figure 1, where the lower part of the base 9 is located below a high stop which can be formed by an 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 support piece can be placed towards a second position, or low position, under the effect of gravity or of a hydraulic pumping. In the low position, a shutter 12b placed at the lower end of the support piece 9 cooperates with a seat 12a integral with the casing, so as to prevent any circulation of fluid.

The member comprising the shutter 12b and the seat 12a makes it possible to control the circulation of fluid through the casing at the level of said member.

The support piece 9 as well as the internal shoulder 11 has recesses with bare bores allowing a hydraulic fluid to flow throughout the casing 6, around the centering guide 8, as long as the shutter 12b does not cooperate with the seat 12a for closing the casing 6.

As schematically shown in Figures 3A and 3B, the anchoring system 10 may include a W-shaped groove formed in the outer wall is the base 9 of the centering guide 8, this base 9 can rotate about an axis vertical 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 on the FIG. 3A, the notch 10b at the upper part of the groove 10 is released from the 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 can then descend 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 surface.

In this arrangement, the clearance between the support piece 9 and the shoulder 11 can be reconsidered, since the clearance necessary to release the lug 10a from the groove in W no longer has its raison d'être as such.

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 attachment of the packer 7 is first of all attached to the surface at the lower end of the casing 6.

Then introduced into the latter, arranged vertically, the base or support piece 9 provided with the centering guide 8 which is placed in the high position or first position (Fig. 1), the base 9 resting on the lugs 10a by l 'through the anchoring groove 10, by passing through the packer 7 the connecting cable comprising electrical lines 13 previously connected to the base 9.

In other embodiments of the device according to the invention, may, instead of placing the packer 7 between the lower end of the casing 6 and the protective casing 3, remove the protective casing 3, or place the packer 7 above the lower end of the casing, for example at above the level of the upper end of the centering guide 8 when the latter is in its highest position.

The probe (or intervention tool) 2 is then fixed under the packer 7 to the lower end of the connection cable 13 and is thus suspended from the lugs 10a in the high position of FIG. 1. It is then fixed to the lower end of the packer 7 the protective casing of the probe which is housed inside the casing.

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, for example substantially at the level shoe 5, the number of casing elements 6 connected end to end allowing 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 traction cable 17 supporting the l assembly formed by the load bar 16 and the socket 15, until the latter comes to be connected to the male plug 14 fixed on the base 9 seen centering guide comprising for example a tubular element 8 which supports the probe , the centering guide 8 ensuring guiding 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.

In the example considered, the members 15a and 8a respectively consist of a shearable washer carried by the socket 15 or the load bar 16 and arms or knives for retaining this washer, carried by the tubular guide 8. These members 15a and 8a are adapted to be released from each other by sufficient traction exerted on the cable 17 from the surface.

Any other type of known means controlled remotely could be used, such as electric or electro-hydraulic dogs making it possible to secure the load bar 16 of the support part 9.

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).

• on produit un pompage de fluide hydraulique sous pression à travers la canalisation 24 située en surface, de manière à assujettir la zone la située sous le packer 7 à une compression hydraulique en vue d'une fracturation.
  Le fluide pompé circule à travers le tubage 6, autour du guide de centrage 8 (les orifices 8b du guide étant placés pour faciliter le transfert de fluides entre l'intérieur et l'extérieur du guide), à travers la base 9 par des conduits 9d au niveau de la rainure en W et des conduits 9c sur la partie de la base coopérant avec l'épaulement 11, avant de traverser le siège 12a.
• On exerce ensuite une légère traction F sur le câble 17 (fig. 3B) qui permet de désolidariser de l'ergot 10a la base 9 de l'élément tubulaire 8 qui passe alors en position basse correspondant à la figure 2, la sonde 2 étant sortie de son carter protecteur 3 et se trouvant alors dans la partie inférieure non tubée, ou découverte, du puits 1 (Fig. 7). L'obturateur 12b étant alors dans une position lui permettant de coopérer avec le siège 12a pour assurer l'isolation de la zone de fracturation.
• On soulève alors légèrement le guide de centrage 8 et par suite, la sonde 2 elle-même d'une hauteur h (insuffisante pour la faire rentrer dans son carter 3) par une traction exercée sur le câble 17 et, dans cette position de la sonde (Fig. 8), on télécommande depuis la station 29, par l'intermédiaire des câbles 17 et 13, l'ouverture des bras articulés 18 et 19. Les extrémités de ces bras viennent s'ancrer dans la paroi du puits 1, en pressant la sonde 2 contre la portion de paroi diamétralement opposée à ces bras.
• On relâche la traction exercée sur le câble 17 en surface et le support 9 retombe alors dans sa position basse sous l'effet de la gravité. Ceci a pour effet de donner un certain mou au câble 13 ainsi détendu (Fig. 8) et de placer l'obturateur 12b contre le siège 12a avec lequel il coopère pour empêcher toute circulation de fluide entre le tubage et la zone à comprimer.
• On maintient l'obturateur 12b sur le siège 12a en assurant une différence de pression hydraulique adaptée entre l'intérieur du tubage et la zone à fracturer de manière que l'isolement de la zone à fracturer soit effectif. Pour cela, on peut par exemple, soit avantageusement placer et maintenir le tubage à une pression constante et supérieure à celle de la zone, soit contrôler au cours du temps la pression du tubage de façon que sa valeur reste supérieure à celle de la zone de fracturation et que l'obturateur 12b soit toujours appliqué contre le siège 12a.
• On pourrait intervertir l'ordre des opérations de pompage et de mise en place et d'ancrage de la sonde 2. Cependant, la procédure proposée est plus sûre, car au cours du pompage, alors que la base 9 est maintenue grâce à l'ergot 10a coopérant avec la rainure en W dans la position haute, l'obturateur 12b ne risque pas d'obturer soudainement l'organe de contrôle. Cette obturation brutale lors du pompage produirait alors un coup de bélier aux conséquences dommageables.

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, while the base 9 is maintained in the high position:

• a pumping of hydraulic fluid under pressure is produced through the pipe 24 situated on the surface, so as to subject the area 1a situated under the packer 7 to hydraulic compression with a view to fracturing.
  The pumped fluid circulates through the casing 6, around the centering guide 8 (the orifices 8b of the guide being placed to facilitate the transfer of fluids between the inside and the outside of the guide), through the base 9 by conduits 9d at the level of the groove in W and of the conduits 9c on the part of the base cooperating with the shoulder 11, before passing through the seat 12a.
• A slight traction F is then exerted on the cable 17 (fig. 3B) which makes it possible to separate the lug 10a from the base 9 of the tubular element 8 which then passes into the low position corresponding to FIG. 2, the probe 2 being removed from its protective casing 3 and then being located in the undamaged lower part , or discovery, of well 1 (Fig. 7). The shutter 12b then being in a position allowing it to cooperate with the seat 12a to insulate the fracturing zone.
• The centering guide 8 is then slightly raised and, consequently, the probe 2 itself of 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 9 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) and of placing the shutter 12b against the seat 12a with which it cooperates to prevent any circulation of fluid between the casing and the area to be compressed.
• The shutter 12b is maintained on the seat 12a while ensuring a suitable hydraulic pressure difference between the interior of the casing and the zone to be fractured so that the isolation of the zone to be fractured is effective. For this, one can for example either advantageously place and maintain the casing at a constant pressure and greater than that of the zone, or control over time the pressure of the casing so that its value remains greater than that of the zone of fracturing and that the shutter 12b is always applied against the seat 12a.
• We could reverse the order of pumping operations and placing and anchoring the probe 2. However, the proposed procedure is safer, because during pumping, while the base 9 is maintained thanks to the lug 10a cooperating with the groove in W in the high position, the shutter 12b does not risk suddenly closing the control member. This sudden plugging during pumping would then produce a water hammer with damaging consequences.

The device according to the invention, described above, makes it possible to remove said set of instruments 2 from the vibrations of said casing 6 during measurement or intervention. The means enabling it 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 part -support 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 set of instruments 2.

• on décomprime le tubage de manière que l'obturateur 12b ne soit plus appliqué contre le siège 12a,
• on télécommande de la surface la fermeture des bras articulés 18 et 19,
• on rentre la sonde 2 dans son carter protecteur 3 par une traction sur le câble 17 replaçant la base 9 du guide de centrage 8 dans la position haute de la figure 1 où cette base est soutenue par l'ergot 10a. L'engagement de la rainure 10 et des ergots 10a s'effectue d'une manière analogue à celle décrite ci-dessus en se référant aux figures 3A et 3B.
• Bien que l'on ait déjà pu décomprimer lentement les formations géologiques en réduisant la pression dans la canalisation 24, dès que l'obturateur 12b ne coopère plus avec le siège 12a pour empêcher toute circulation de fluides, on pourra réaliser cette décompression seulement une fois que la sonde 2 a été rentrée dans son carter protecteur 3.

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.
When the various operations or measures are completed:

• the casing is decompressed so that the shutter 12b is no longer applied against the seat 12a,
• the closure of the articulated arms 18 is remote controlled from the surface and 19,
• the probe 2 is returned to its protective casing 3 by pulling on the cable 17 replacing the base 9 of the centering guide 8 in the high position of FIG. 1 where this base is supported by the lug 10a. The engagement of the groove 10 and the lugs 10a takes place in a manner analogous to that described above with reference to FIGS. 3A and 3B.
• Although we have already been able to slowly decompress the geological formations by reducing the pressure in the pipe 24, as soon as the shutter 12b no longer cooperates with the seat 12a to prevent any circulation of fluids, this decompression can only be carried out once that the probe 2 has been returned to its protective casing 3.

According to the invention, it will be possible to carry out successive pressurizations of the zone to be fractured by opening the control member 12a, 12b, by depressurizing the casing 6, then lifting the shutter 12b before performing a re-pumping and closing of the control member 12a, 12b.

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 2, 8, 9, 13, 12b 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 in area.

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 placing the member 7 close shoe 5 and limit the length of the overhang between the base of the 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 7a 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 compressed hydraulic fluid 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 means 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 area delimited by the two sealing members, the casing 4 is perforated in a conventional manner, in order to allow the fluid injected hydraulic to flow through the formations located at this level.

When the entire device is under hydraulic pressure, it is possible to move the probe 2 by simply pulling the cable 17 from the surface, after having remote-controlled the closing 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 relax 13 tension in the cable 13 before performing the measurement or intervention using the probe or instrument 2.

The description of the invention illustrated by FIGS. 1 to 8 uses as a member for controlling the circulation of the fluid between the casing and the area to be compressed, a member comprising a shutter secured to the traction cable cooperating with a seat secured to the casing and said member is adapted to allow any circulation of fluid when traction by said cable is exerted on the shutter.

It will not depart from the scope of the present invention to use any other control member operable by a cable, in particular a member comprising a shutter secured to the traction cable cooperating with a seat secured to the casing, said member preventing any circulation of fluid at its when an appropriate pull is exerted on said shutter, the probe being placed below the shutter.

• de ne placer le tubage en pression et de ne pas maintenir l'obturateur contre le siège en tirant sur le câble puisque l'effet de la pression dans ladite zone produit la fermeture naturelle dudit organe une fois que l'obturateur a été plaqué contre le siège,
• de pouvoir éventuellement repressuriser la zone à fracturer d'une manière très simple.

Such an arrangement offers the double advantage, while the fracturing zone is under pressure:

• not to put the casing under pressure and not to maintain the shutter against the seat by pulling on the cable since the effect of the pressure in said zone produces the natural closure of said member once the shutter has been pressed against the seat,
• to be able to repressurize the area to be fractured in a very simple way.

The latter device however has the disadvantage of being more complex to use than that illustrated in FIGS. 1 to 8, when a sliding of the probe occurs, resulting in an undesired tension of the connection cable.

In the first device described, it suffices, after having opened the control member, to undock the probe from the well, to pull on the cable 17 to reassemble it, then to re-anchor it before releasing the cable, while for the last device described, it is necessary to clear the packers and to produce a movement of the casing aimed at relaxing the connection cable.

When the passage sections allow it, in particular in line with the packer 7 and the seat 12a, the first device described also has the advantage of making it possible to slide the set of instruments 2, the shutter 12b and the cable traction along the casing 6, the load bar, the groove in W, the centering guide can then be removed.

According to another embodiment of the invention, represented in FIG. 9, the probe 2 is located in an area 1c of the well in which no fracturing will be carried out. Fracturing is carried out in a zone 1b delimited by two sealing members 33 and 34 which, in the example of FIG. 9, are supported by the casing 6.

The cable 17, which is connected to the surface, is terminated at its lower end by an electrical connection member 15 surmounted by a load bar 16 making it possible to lower the cable into said casing.

The load or ballast bar 16 is centered on the base 9 by means of the guide 8 and then anchored to it. The means for anchoring may include, for example, dogs 16c (electric or electro-hydraulic, integral with the load bar 16 and controlled from the surface) cooperating with notches 8a formed in the body of the guide 8 or of the base 9. One could also use the mechanical anchoring means described and illustrated in the first embodiment according to the invention.

The connection member 15 which is a female socket, cooperates with a complementary connection member 14 which is a male socket secured to the base 9 and connected to the probe 2 or to the members and instruments to be connected to the surface.

This second embodiment of the device according to the invention differs from the first in that there is interposed between the base 9 and the flexible and flexible connecting cable 13, a rigid shaft 30, integral with the base 9, this shaft being movable in translation and cooperating with insulation means 31, integral with the casing 6, to prevent the fluid contained in the casing from escaping from its lower end. The insulation can be made by means of an O-ring placed in a groove and cooperating with a smooth exterior surface of said shaft 30.

The device comprises a member 12a, 12b controlling the circulation of fluid coming from the casing and going towards the zone to be compressed, with a view to its hydraulic fracturing, through one or more passages 32 formed in the casing 6.

The control member 12a, 12b of FIG. 9, comprises a shutter 12b which is integral with the base 9 or said shaft 30 and cooperates with a seat 12a integral with the casing 6.

The stroke of the base 9 is limited in the high position by the movement of the retaining lug 10a in the groove 10 in W, and in the low position by the contact of the shutter 12b on the seat 12a.

We can limit the stroke of the base at its high position, especially when the anchoring system 16a, 8c of the load bar to the base is erased by traction on the cable 17, by means of a stop 11 placed above the centering guide 8 at a sufficient distance to allow the lug 10a to play with the groove 10 in W. By this arrangement, the possible deterioration of the lug 10a and the groove 10 is avoided during shearing of the anchoring means.

In FIG. 9, the probe 2 is held in a protective casing 3 placed at the lower end of the casing 6. By extending the casing 3 or by interposing tubular elements between the casing 6 and the casing 3, and by adapting the length of the connecting cable 13, it will be possible to carry out measurements or / and interventions at a point remote from the compression zone.

The stroke of the base inside the casing as well as the shaft 30 are adapted so that the probe or the set of instruments can be separated by a sufficient distance from the protective casing, in order to carry out the measurements. or / and interventions.

To carry out the circulation of the fluid towards the control member 12a, 12b, different passages are provided 8b, 10f respectively through the flared part of the centering guide 8, the body of the groove 10 in W.

In Figure 9, the connecting cable 13 is attached to the lower end of the shaft 30, but the shaft 30 may include a hollow part and resistant to compression pressure, in which the connecting cable is attached. This has in particular the aim of increasing the length of the connecting cable 13 and, by this very fact, its flexibility.

To measure the fracturing pressure of zone 1b, a pressure sensor 36 can be placed on the shaft 30 directly connected to the electrical lines connected to the surface.

• a) l'ensemble constitué par le tubage 6, les organes d'étanchéité 33 et 34, le support de sonde 9, le guide de centrage 8, l'organe de contrôle 12a, 12b, l'arbre 30, le câble de liaison 13, la sonde 2, le carter protecteur 3, est descendu dans le puits. La base est maintenue grâce à la coopération de l'ergot 10a et de la rainure 10 en W dans la position haute, la sonde étant protégée par le carter 3,
• b) les organes d'étanchéité sont mis en place,
• c) on descend depuis la surface un connecteur 15, 16 relié au câble 17, le connecteur venant coopérer avec la base 9, de manière à assurer une liaison électrique et mécanique,
• d) on met en compression la zone à fracturer 1b,
• e) on descend la base 9 au moyen du câble 17 relié à la surface, jusqu'à ce que la sonde 2 ait atteint sa position d'ancrage et soit sortie du carter protecteur,
• f) on ancre la sonde,
• g) on poursuit la descente de la base 9, jusqu'à ce que l'obturateur 12b vienne en butée contre le siège 12a, le câble de liaison entre l'arbre 30 et la sonde 2 étant relaché,
• h) on maintient l'obturateur 12b sur le siège 12a en produisant une pression suffisante dans le tubage, et
• i) on effectue les mesures ou/et interventions.

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

• a) the assembly constituted by the casing 6, the sealing members 33 and 34, the probe support 9, the centering guide 8, the control member 12a, 12b, the shaft 30, the connecting cable 13, the probe 2, the protective casing 3, is lowered into the well. The base is maintained thanks to the cooperation of the lug 10a and the groove 10 in W in the high position, the probe being protected by the casing 3,
• b) the sealing members are put in place,
• c) a connector 15, 16 connected to the cable 17 is lowered from the surface, the connector coming to cooperate with the base 9, so as to provide an electrical and mechanical connection,
• d) the zone to be fractured 1b is put under compression,
• e) the base 9 is lowered by means of the cable 17 connected to the surface, until the probe 2 has reached its anchoring position and has left the protective casing,
• f) the probe is anchored,
• g) the base 9 continues to descend, until the shutter 12b abuts against the seat 12a, the connection cable between the shaft 30 and the probe 2 being released,
• h) the shutter 12b is maintained on the seat 12a while producing sufficient pressure in the casing, and
• i) the measurements or / and interventions are carried out.

We can reverse the order of certain steps, however, as was mentioned in the description of the first embodiment, it is better to compress the area when the base 9 is in the high position, rather than anchoring the probe 2 before hydraulic compression.

When the sealing members 33, 34 are of the hydraulic anchoring type, the control member can be closed and the casing pressurized to put these members in place. For this, the hydraulic connection allowing the actuation of the member 34, must lead to a level higher than that of the sealing member 12a, 12b, that is to say at a point in the casing which can be pressurized without the area to be fractured.

For a possible recompression of the zone to be fractured, it suffices to release the pressure in the casing, to separate the obturator 12b from the seat 12a by a sufficient distance, which requires or not the lifting of the probe 2, to recompress the area to be fractured, possibly putting the probe back in place, bringing the obturator 12b into contact, ensuring pressure in the casing to keep the latter 12a, 12b in contact.

According to this embodiment of the invention, there is a system substantially balanced in pressure, since the pressure forces or fracturing fluid are exerted on the two sealing members 33, 34 in opposite directions and, as a result , the casing 6 is not not subjected to a vertical force due to the pressure forces of the fracturing fluid.

This embodiment makes it possible to move the probe 2 after anchoring of the sealing members 33, 34 and even during compression. For this reason, the anchoring members 8c, 16a and the retaining means 10, 10a must allow the transmission of a tensile force sufficient to overcome the action of the pressure forces acting on the cross section of the shaft 30 .

This embodiment of the invention can also be used when it is desired to carry out the measurements or / and interventions in the compression zone. For this, it suffices to remove the lower seal produced by the annular member 33 of the packer type.

Figure 10 illustrates a variant of the embodiment according to the invention illustrated in Figure 9 and differs from the previous in that the fluid flow control member is of a sliding type attached to the periphery of the support 9, in that the stop of the base is adapted accordingly and, in that the fluid pressure sensor of the compression zone is not mounted on the shaft.

The control member comprises a shutter 12b comprising a sliding jacket at the ends of which are placed two seals 35, such as O-rings, and comprises a seat 12a produced in the internal wall of the casing 6. The seat has an orifice 32 through which the fluid passes to the area to be compressed.

The seat 12a is adapted to cooperate with the shutter 12b to ensure the seal between the interior of the casing and the area to be compressed, when the support 9 is sufficiently lowered so that the jacket 12a closes the orifice 32. The second position , or low position, of the support is obtained when one of the ends of the jacket 12b has reached the bottom 37 of the casing, while the shutter 12b cooperates with the seat 12a to prevent any circulation of fluid through the orifice 32.

Instead of the jacket itself coming into abutment on the bottom 37 of the casing, one could have placed on this bottom a stop cooperating with the base 9 or the shaft 30 to ensure the same effect.

The pressure sensor 36 is located in the shutter 12b at a level such that it is in hydraulic connection with the compressed area when the shutter is in abutment. A groove 38 making all around the shutter 12b and in which the sensor 36 is located allows its connection with the compression zone 1b whatever the indexing of the support with respect to the casing.

We will not depart from the scope of the present invention by dispensing the casing 6 of the protective casing 3. We will then be able to reduce the stroke of the base 9.

To control the circulation of fluid between the compression zone and the casing, it is possible to use an electrical member controlled remotely by the cable connected to the surface. This notably offers the advantage of decoupling the control of the member for controlling the movement of the support 9, in particular when it is desired to move the probe 2.

Claims (15)

1. Device making it possible to perform measurements and/or operations in a well (1) in which hydraulic compression, such as hydraulic fracturing, is effected in a first zone, and in which measurements and/or operations are performed in a second zone, comprising a casing (6) with a diameter less than that of the well (1), and comprising an orifice (7a, 32) through which the compression fluid passes to the hydraulic compression zone, a set (2) of one or more instruments fixed to a flexible connecting cable (13) linked to a control unit (8, 9, 10), connected to the surface by a cable (17), the said unit comprising a support (9) and means (10) for anchoring the said support (9) to the casing (6), the said set of instruments (2) being able to be mechanically disconnected from the casing (6) by means of the control unit, the support (9) of the control unit comprising an obturation component (12b), the casing (6) incorporating a seat (12a) for interacting with the said obturation component (12b), the said interaction being obtained after disconnection of the support (9) from the said casing (6), characterised in that the said obturation component (12b) controls the flow of the said fluid through the said transit orifice (7a, 32).

2. Device according to claim 1, characterised in that it comprises a casing (6), two annular sealing devices (33, 34) interacting with the said casing (6) and the wall of the well to define the said compression zone (1b), a set (2) of at least one instrument connected by a flexible connection (13) to a shaft (30) secured to a base (9) connected to the surface by a cable (17), the said shaft (30) being movable in translation and interacting with isolation means (31) secured to the casing (6) to prevent the fluid contained in the casing (6) from escaping from it through the bottom end of this casing, a component (12a, 12b) situated close to the bottom part of the casing (6) (Figs 9 and 10).

3. Device according to claim 1, usable when the said first compression zone is merged with the said second measurement and/or operation zone, characterised in that it comprises an expandable annular sealing device surrounding the casing (6) at its bottom part.

4. Device according to one of claims 1 to 3, characterised in that the said casing has at its bottom end a protective housing (3) in which the said set of instruments (2) can be accommodated and the said device comprises a control unit (8, 9, 10) allowing the fluid to circulate through the said unit when a controlled traction is exerted on the said cable and in that the said device comprises a support member or base (9) movable in the casing, located on the said traction cable (17) and suitable for holding the said set (2) in the said housing (3) when it is in a first position, and on the one hand allowing the said set to move out of the housing and move away from the casing (6), and on the other hand making it possible to prevent any circulation of fluid between the casing (6) and the said compression zone (1a), when the said support member (9) is in a second position.

5. Device according to one of claims 1 to 4, characterised in that the coupling, by means of the cable (17) comprising at least one electrical conductor, between the connecting device (15) fitted to the end of the said cable (17) and a complementary connecting device (14) secured to the base (9), the said coupling being suitable for interacting to produce electrical continuity in the electrical conductor or conductors between the cable (17) and the set of instruments (2) and/or the said control unit (12a, 12b).

6. Device according to one of claims 1 to 5, characterised in that the base (9) or support member (9) comprises retaining means, such as an anchoring system (9a, 10f) suitable for interacting with retaining members (10a) secured to the said base (9), the said means maintaining the said base in a first position in which the said base is at a distance from the bottom end of the casing, and in that these means can be released by means of the cable (17) connected to the surface, and characterised in that the movement of the said base (9) into one or other of the two positions produces an opening or closing of the said control device and optionally produces the movement of the said set of instruments (2) relative to the said casing.

7. Device according to one of claims 1 to 6, characterised in that the said control unit is electrical and in that it is suitable for being controlled by means of the cable (17) connected to the surface.

8. Method for performing measurements and/or operations in a well (1) by using the device according to one of claims 1 to 7, characterised in that the sealing device (12b) is controlled by means of the said cable (17) and/or the pressure differential on each side of the said transit orifice (7a, 32).

9. Method according to claim 8, in which the said first compression zone and the said second measurement and/or operation zone are merged and disposed at the bottom end of the casing (Figs 1, 2, 3c), characterised in that when a controlled traction is produced on the said obturation component through the said cable, fluid is allowed to circulate through the said device.

10. Method according to claim 8, in which the said first compression zone and the said second measurement and/or operation zone are merged and disposed at the bottom end of the casing (Figs 1, 2, 3c), characterised in that when a controlled traction is produced on the said obturation component (12b) through the said cable (17), all circulation of fluid through the said component is prevented.

11. Method according to one of claims 8 to 10, characterised in that the said control unit is maintained in a position preventing any circulation of fluid, by producing a controlled pressure difference between the said casing (6) and the said zone to be fractured (1a), namely on each side of the said transit orifice (7a, 32).

12. Method according to one of claims 8 to 11, characterised in that by means of the said cable (17), the said set of instruments (2) is moved relative to the said casing (6).

13. Method according to one of claims 8 to 12, characterised in that it comprises the following steps for performing the said measurements and/or operations:

a) the said casing (6) is positioned in the said well,

b) the said set of instruments (2) is anchored to the said measurement and/or operation zone (12) in the well (1),

c) the tension is released from the flexible connection (13),

d) a hydraulic pressure is produced in the said compression zone (1b), and

e) the said transit orifice is closed off by means of the obturation component (12b).

14. Method according to claim 8 in which the said obturation component (12b) allows all circulation of fluid when a controlled traction is exerted on the said cable (17) connected to the surface and where the seat (12a) has a cross section sufficient to allow the said set of instruments (2) to pass through it, characterised in that it comprises the following steps:

f) the said casing (6) is positioned in the said well (1),

g) the said set (2) is caused to slide in the said casing (6),

h) the said set of instruments (2) is anchored in the well (1) at the level of the zone (1a) to be fractured,

i) the tension is released from the connecting cable (13),

j) a hydraulic pressure is produced in the said fracturing zone (1a) so as to bring about the fracturing, and

k) the said control unit (12a, 12b) is obturated.

15. Method according to one of claims 8 to 14, in which the said set of instruments (2) is connected by the said electrical connection (13) to an electrical connecting device (14, 15) and in which the said cable (17) connected to the surface comprises at least one transmission line, characterised in that it comprises the following steps:

l) the said set of instruments (2) is equipped with an electrical connecting plug (14) which can be plugged in in a liquid environment,

m) the said set is positioned at the end of the casing (6) and the said connecting device (14) is placed in a position allowing connection to a complementary device (15) connected to the cable connected to the surface (17) and coming from the top end of the casing, and then

n) a transmission cable (17) fitted with the said complementary electrical connecting device (15), suitable for being connected to the said connecting device (14) connected to the said set of instruments (2), is introduced into the casing (6).

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