EP0345112A1 - Device for anchoring a probe in a well by expanding mobile arms - Google Patents

Abstract

Device for anchoring a probe (1) in a well by the expanding, controlled remotely from the surface, of at least one anchoring arm (7) held in a closing position by a retractable bolt (24) engaged in a rod (17) connected to the anchoring arm by means of links (9, 11). <??>The external pressure is exerted on the bolt (24) permanently (via the orifices 21, 21A), the bolt being fixed to a head (25) movable in a cavity (26). Means contained in an inner space (29) of the body make it possible to exert on the head (25) pressure proportional to the external pressure, thus keeping the bolt blocked in the rod (17), or a much lower pressure, with the result that the bolt is released. <??>The invention is used, for example, in oil prospecting. <IMAGE>

Description

The subject of the invention is an improved device for anchoring a probe in a well by spacing movable anchoring arms which are applied against the walls. By the FR patent. 2,548,727, there is known a device for anchoring a probe in a well by spacing of mobile anchoring arms coming to apply against the walls.

The probe is equipped, for example, with measuring equipment intended for the study of the geological formations encountered or for carrying out seismic prospecting operations. It is suspended from an electro-carrying cable comprising power supply lines for the measuring equipment and signal transmission lines.

The anchoring device described in the cited earlier patent comprises at least one spring, a rod driven in translation by the rebound of the spring, means for transforming the translational movement of the rod into a pivoting movement of at least one arm anchor and means for intermittently immobilizing the rod in the spring compression position. The immobilization means comprise a lock adapted to come into engagement in a radial recess of the rod in the compression position of the spring and of the hydraulic means for moving the lock.

The hydraulic means may include a cavity formed in the body of the device, a head secured to the translational lock and adapted to slide in the cavity, and a hydraulic circuit for intermittently applying unequal pressures on the two opposite faces of the head. , one of the two pressures being equal to the pressure prevailing in the well at the chosen depth where the device is immobilized. The application of the two unequal pressures is carried out for example by means of a solenoid valve.

The device being most often used at a depth of several hundred meters deep where the pressure is high, the force to which the lock is subjected due to the differential pressure applied to the piston, is considerable and allows a very safe release and very frank about the opening of the arm.

It has been found in use, however, that accidental trips could occur even though the solenoid valve is in the closed position and isolates the lock from the well pressure. This is due to leaks which place the hydraulic fluid in the lock control circuit unexpectedly in equi-pressure with the pressure prevailing in the well and cause the lock to move back.

The present invention relates to a new embodiment of the device making it possible to avoid any untimely triggering of each anchoring arm.

The hydraulic means include, like the embodiment of the prior patent, a cavity formed in the body of the device, a head secured to the lock in translation and adapted to slide in the cavity, the section of the head being greater than that of the lock. , and a hydraulic circuit for applying variable pressure to the head of the lock.

It is characterized in that it comprises pressure applying means for applying to the lock permanently a pressure equal to that prevailing in the well and to the head integral with the lock an opposing pressure which can vary between a first pressure whose value is sufficient to move the lock to its position engagement in the radial recess of the rod, and a second value low enough for the lock to be pushed towards its release position.

The pressure application means comprise for example a pipe opening into the cavity on the side of the head opposite the bolt and switching means for selectively applying to the head the first pressure or the second pressure.

The pressure applying means comprise first and second chambers of different sections formed in the body of the probe, first and second pistons of different sections adapted respectively to the sections of the first and second chambers, the first piston of lower section being permanently exposed to pressure in the well, the second chamber where the second piston moves communicating with said pipe, which is intermittently connected to a volume where there is a pressure lower than the pressure prevailing in the well by l 'through a solenoid valve.

With such an arrangement, any possible leak which would put the fluid in the pipe at a pressure identical to that which prevails in the well, can only further increase the resulting forces applied to the assembly of the bolt and the head and which hold in the locked position. Any unexpected trigger becomes impossible.

• - la figure 1 représente une vue partielle de la sonde qui montre le dispositif d'ancrage en position de verrouillage maintenant fermé un bras d'ancrage,
• - la figure 2 montre en détail les moyens d'application de pression dans une position permettant le verrouillage du bras d'ancrage en position de fermeture,
• - la figure 3 représente une vue analogue à la figure 1 où le dispositif d'ancrage a été déclenché pour permettre l'écartement du bras et,
• - la figure 4 a une vue analogue à celle de la figure 2 où les moyens d'application de pression sont représentés dans une position permettant le déclenchement du verrou d'ancrage.

Other characteristics and advantages of the device will appear better on reading the description of the new embodiment and with reference to the appended drawings where:

• FIG. 1 represents a partial view of the probe which shows the anchoring device in the locked position, now holding an anchoring arm,
• FIG. 2 shows in detail the means for applying pressure in a position allowing the locking of the anchoring arm in the closed position,
• FIG. 3 represents a view similar to FIG. 1 where the anchoring device has been triggered to allow the arm to be separated and,
• - Figure 4 has a view similar to that of Figure 2 where the pressure application means are shown in a position allowing the release of the anchor lock.

The anchoring device shown in FIGS. 1 and 2 is associated with a tubular probe 1 comprising an upper part 2 and a lower part 3 made integral with one another by several bars 4.

The measuring apparatus, consisting of geophones for example, is contained in a compartment 5 of the lower part 3 of the probe and connected to a multi-function cable supporting the probe by electrical conductors (not shown) passing for example to the inside the bars 4.

One of the bars 4 has an axis 6 around which an anchor arm can pivot 7. On an axis 8 fixed to the anchor arm 7 at a certain distance from the axis 6, is articulated a first end of a first operating arm 9. On an axis 10 integral with another bar 4, is articulated a first end of a second operating arm 11. The second ends of the two operating arms 9, 11 can pivot relative to a common axis 12. On this common axis can also pivot a first end of a third operating arm 13.

The anchoring device also comprises a rod 14 provided with a recess 15 at the bottom of which is fixed a hinge pin 16 for the second end of the third operating arm 13. The rod can slide in a cylindrical guide housing 17 formed in the axis of the body 18 of the probe.

A helical spring 19 bearing at a first end on the body of the probe and at a second end on a shoulder 20 of the rod 14, exerts on the latter a force tending to cause it to come out of its guide housing 17. An axial channel 21 is formed in the upper part of the rod 14. It communicates with a radial bore 21A opening outside the body 18.

The upper part of the housing 17 is extended by a chamber 22 of upper section containing a hydraulic liquid. A piston 23 consisting of two parts of different sections 51 and 52, is adapted to slide freely and sealingly in the chamber 22 and the upper part of the guide housing 17, under the action of the possible pressure difference between the pressure hydraulic fluid and that prevailing in the well, so as to cancel this pressure difference.

The device also comprises a latch 24 provided with a head 25 of larger section which can be moved inside a cylindrical cavity 26 formed radially in the body 18 of the probe, between a withdrawal position where the latch is fully retracted at the interior of said body and an advanced position where it projects into the interior of the guide housing 17. A recess 27 (Fig. 3-4) is formed radially in the rod 14 for the latch 24. It opens into the central channel 21 of the rod 14 and thus the pressure Pe prevailing in the well is applied permanently to the lock on the side of the rod 14. The cavity 26 is closed externally by a plug 28.

The dimensions of the operating arms and the location of the hinge pins 8, 10, 12 and of the housing 27 are chosen so that, when the anchoring arm 7 is in the closed position along the body of the probe, the helical spring 19 is bandaged and the lock is engaged in the recess 27.

The pressure application means enabling the arm 7 to be unlocked are arranged in a housing 29 of the body, the details of which are shown in FIGS. 2 and 4. They firstly comprise an attached tubular part 30 of section adapted to that of the chamber 22 and fixed therein by screwing. The part 30 has a cylindrical interior cavity 31 closed on the side of the piston 23 and open on the opposite side. Chamber 22 is extended by another chamber 32 of larger section. In this chamber 32 is arranged a solenoid valve 33 provided with a threaded end piece 33A which is screwed onto the tubular part 30 at its open end. The solenoid valve 33 comprises a movable piston L of section adapted to that of the cavity 31.

A circular groove 34 is formed in the wall of the tubular part 30 around the piston L. A first longitudinal pipe 35 connects the groove 34 and the chamber 22 between the free piston 23 and the closed end of the tubular part 30. By a second pipe 36 formed longitudinally in the wall of the body 18, the groove 34 communicates with the cavity 26 or moves the head 25 of the latch. A second circular groove 37 is formed in the interior wall of the chamber 22 around the insert 30. A first radial bore 38 in the wall of the insert 30 communicates the interior cavity 31 with the groove 37. A second, 39, in the outer wall of the body, communicates the groove 37 with the outside of the probe. This second bore 39 is closed by a threaded plug 40. Two other radial bores 41, 42 are also provided in the wall of the body. At a first end, they both open to the outside of the body and are respectively closed by two threaded plugs 43, 44. At their opposite end, they communicate respectively with the two parts of the chamber 22 on either side of the free piston 23, the first on the side of the insert 30, the second on the side of the channel 21 in the rod 14.

Seals 45, 46, 47, 48, 49 are respectively disposed around the piston P, the insert 30, the piston 23, the rod 14 and the latch 24, to allow their leaktight sliding.

The solenoid valve 33 is connected by conductors 50 to a transmission line included in the electro-carrying cable (not shown). In the rest position, the piston L is in the extended position (Fig. 1, 2) and isolates the interior of the cavity 31 from the groove 34.

When the solenoid valve 33 is activated, the piston P moves back enough (Fig. 3, 4) to make the cavity 31 communicate with the groove 34 and therefore with the pipe 36.

When the solenoid valve is in the rest position, the external pressure Pe is exerted via the channel 21 in the rod 14 and the recess 27, on the face of the smallest section S2 of the free piston 23 and on the lock 24 of section S3.

) Pe      (1)The hydraulic fluid pressure in the chamber 22 on the side of the free piston opposite the rod 14 is reduced in the ratio S1 / S2. This reduced hydraulic pressure is transmitted in the cavity 26 via the pipes 35 and 36 and is exerted on the head 25 secured to the lock, the section of which is S4. The resulting force Fr applied to latch 24 can be expressed by the relation:
Fr = (S3 - S4

) Pe (1)

The different sections S1 to S4 are chosen so that the force Fr is centripetal and has the effect of driving the lock into the recess 27 (Fig. 3, 4) of the rod in the closed position of the anchoring arm.

The device works as follows:

The probe being on the surface, and the solenoid valve 33 being closed so as to isolate the interior chamber 31, the threaded plug 40 is opened to purge it of the oil which it can contain and it is filled with air. at a low pressure p, (atmospheric pressure for example). Via the channel 42, a vacuum is created in the part of the chamber 22 opposite the insert 30.

Oil is injected into the chamber 22 through the pipe 41 in sufficient quantity to fill the pipes 35, 36, the groove 34 and the cavity 26, and purge them of air.

The resulting force Fr exerted on the latch 24 (see relation 1) is sufficient to push the latter against the rod 14. When the anchoring arm 7 is brought into the closed position against the wall of the body (Fig. 1 ) by compressing the helical spring 19, it causes the withdrawal of the rod 14 inside its guide housing 17 to its cocking position where the latch 24 is inserted into the recess. The anchor arm is locked.

To check the locking, a relatively high hydraulic pressure can be injected into the chamber 22 and the cavity 26 at least momentarily.

The probe is then lowered into the well. As it descends, the external pressure increases. The recoil of the free piston 23 inside the chamber 22 under the action of this pressure which is applied to it by the axial channel 21, makes it possible to equalize with each instant the pressure of the hydraulic liquid contained in the chamber 22 with that prevailing in the well.

When the probe has reached the chosen depth where it must be anchored, the solenoid valve 33 is actuated so that the piston P moves back (Fig. 3, 4) and puts the lines 35, 36 into communication with the interior cavity 31 at very low pressure p. The lock is subjected on the side of the axial channel 21 to a force equal to Pe.S3 and on the opposite side to a force equal to p.S4 the result is a centrifugal force sufficient to overcome the friction forces of the lock 24 in its recess 27 of the rod 14 and drive it towards its withdrawal position (Fig. 3, 4).

The rod 14 is released and, under the action of the helical spring 19, is pushed outwards from its guide housing 17. The pivoting of the operating arms 9, 11, 13 resulting from this movement has the effect of rotate the anchoring arm 7 and, when it comes to bear on the wall, press the probe 1 against the opposite wall of the well. The apparatus contained in the probe can then be used.

The opposing pressures exerted on the bolt and the head are constantly one equal, the other proportional to the external pressure and possible leaks cannot change the direction of the result of the forces which keeps them in the locked position.

It would not go beyond the scope of the invention to use the same hydraulic system to control the simultaneous unlocking of several anchoring arms such as arm 7.

Claims (4)

1 - Improved device for anchoring a probe in a well by spacing at least one anchoring arm (7) which can pivot relative to the body (18) of the probe, comprising at least one spring (19), a rod (14) driven in translation by the rebound of the spring, means for transforming the translational movement of the rod into a pivoting movement of the anchoring arm and means for intermittently immobilizing the rod in the compression position of the spring which comprise a lock (24) adapted to come to engage in a radial recess (27) of the rod in the compression position of the spring, and hydraulic means for moving the lock towards a release position where the rod is released , which means comprise a cavity (26) formed in the body (18) of the probe, a head (25) integral with the latch (24) in translation and adapted to slide in said cavity (26), the section of the head being greater than that of the lock, and a hydraulic circuit p or to apply a variable pressure to the head of the bolt, characterized in that it comprises pressure applying means for permanently applying to the bolt (24) a pressure equal to that prevailing in the well, and to the head (25 ) integral with the lock, an opposing pressure which may vary between a first pressure whose value is sufficient to move the lock towards its position of engagement in the radial recess (27) of the rod, and a second value low enough for the latch is pushed to its release position. 2 - Anchoring device according to claim 1, characterized in that the hydraulic circuit comprises a pipe (35, 36) opening into the cavity (26) on the side of the head opposite the latch (24) and switching means ( 33) to selectively apply the first or second pressure to the head. 3 - Anchoring device according to claim 2, characterized in that the pressure application means comprise first and second chambers (17, 22) of different sections formed in the body of the probe, a piston (23) comprising two parts of different sections adapted respectively to the sections of the first and second chambers, the part of the piston (23) of smaller section being permanently exposed to the pressure in the well, the second chamber (22) where moves the part of larger section of the piston (23) communicating with said pipe (35, 36), which is connected to a volume (31) where a pressure prevails lower than the pressure prevailing in the well, by means of a solenoid valve (33), the pressure applying means further comprising openings (21, 21a, 27) for applying the external pressure to the lock. 4 - Anchoring device according to claim 3, characterized in that the pressure application means comprise an insert (30) provided with an internal cavity (31), a piston (P) associated with the electro- valve (33) and movable between a position for closing the interior cavity and a position where said interior cavity is put in communication with said second chamber (22) and with said cavity (26) where the head (26) of the lock.

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