EP1570150B1 - One-step directional coring or drilling system - Google Patents

Abstract

An assembly for sidetracked drilling in a wall of a borehole previously drilled or cored in a formation includes a guide element and an expansible device fixed to the front end of the guide element operable to be selectively expanded by an actuation means. A sidetracking channel is formed in the guide element in alignment with an internal space, upstream of the expansible device in the direction of advance. A longitudinal cavity is formed in the guide element parallel to the longitudinal axis and arranged to allow passage from the internal space to the actuation means of the expansible device. Within the internal space of the guide element, an external tube of the core barrel includes a core bit fixed to the front end of the external tube and arranged to slide, after having been released, in the internal space and in the sidetracking channel and then progress to the formation.

Description

The present invention relates to an assembly for coring or deflected drilling in a wall of a borehole drilled or cored beforehand in a formation.

There are many sets for this kind of work but those known to date require a prior operation of setting up the guide element or deflection, separately from the operation of descent of the corer and d use of it. This succession of operations takes a long time which, as we know, is very expensive in this business because of the special specialization of the individuals who practice it, the risks they run, the specific equipment used, the technical complexity operations that must be carried out, etc., ... There is also the risk of losing expensive equipment in the ground at each descent and climb operation and, often because of this, to lose more access to the borehole.

In order to avoid a maximum of these risks, and to save operating time, the object of the present invention is to propose an assembly with which the guide or deflection element and the corer are lowered in one operation. Such a deviated coring system is described in patent EP 0 514 657 A.

For this purpose, the cored or deflected bore assembly of the invention includes a guide member whose outer diameter is selected to be able to enter the borehole to a desired depth for the deviated core, and which is from a posterior end, in a direction of advance of the coring or drilling towards the bottom of the borehole, a coaxial internal space of a diameter adapted to house a corer.

An expandable device, attached to the forward end of the guide member, has an outer side surface which, in a rest state, has a cross section smaller than that of the borehole and which is arranged to take, in a dilated state of the device, an immobilizing support of said assembly against the wall of the borehole. The expandable device comprises selective actuation means arranged to receive a pressurized fluid which causes expansion of the expansible device beyond a determined pressure of the fluid, and a valve arranged to oppose automatically an outlet of this fluid. determined pressure out of said actuating means.

A deflection channel is hollowed out in the guide element in extension of the internal space, upstream of the expandable device along said direction of advance. The deflection channel has a posterior end coaxial with said internal space, a bottom and lateral sides which follow, from this posterior end of the channel and towards the expandable device, a direction inclined with respect to the longitudinal axis of the guiding element, the bottom intersecting this axis. The channel extends to fully open the guide member, on the other side of the longitudinal axis, at an angle to the aforesaid wall which is chosen for the deviated coring. The deflection channel has a cross section adapted so that it can pass said core guided by the bottom and sides.

A longitudinal cavity is cut in the guide element parallel to the aforementioned longitudinal axis, and is arranged to allow passage from the aforesaid internal space to the actuating means of the expandable device.

In the internal space of the guide element, possibly even in a posterior portion of the deflection channel, there is arranged an outer tube of the aforementioned corer. This outer tube comprises a coring ring attached to the front end of this outer tube, is suspended from a drill string, and is releasably locked in the guide element, in particular so that the crown is included within an imaginary outer shell of the guide member. The outer tube is arranged to slide, after being released, in the internal space and in the deflection channel and then progress in the formation.

In the outer tube of the corer, temporarily arranged to actuate the expandable device, is mounted a removable tubing which extends from the inside of this outer tube, through the longitudinal cavity, to the selective actuating means. The removable tubing has an open rear end to let pressurized fluid from the drill string. A hooking piece is attached to this rear end and is arranged for a subsequent withdrawal of the tubing out of the aforesaid assembly. An anterior end of said tubing is arranged for a releasable and sealed connection between the tubing and the selective actuating means for communicating thereto, through said tubing, the fluid under pressure.

In this same outer tube, after expanding the expansion device and removing said tubing out of the assembly, it is possible to have either an inner corer tube or a crown plug arranged so that it can make drilling, the inner tube or the cap having a fastening piece attached to its rear end and arranged for its descent and its subsequent withdrawal from the aforesaid assembly.

As can be understood by those skilled in the art upon reading the foregoing, the assembly described above, thus assembled, is lowered into a block in the borehole and can be oriented for the crown to attack the wall. the hole in the desired direction. Only a simple exchange between the removable tubing and either the inner corer tube or said drilling plug must be made before attacking the wall.

For their mutual attachment, the guide element may comprise a sliding member and the expandable device may comprise a chamber in which the sliding member can slide between two stop positions, a position in which the sliding member closes an exit passage. fluid contained under the pressure determined in the dilated expansion device and a position in which this member opens the outlet passage. This arrangement allows to selectively escape at a desired moment the fluid out of the expandable element, so that it can be released from immobilization relative to the wall.

According to one embodiment of the invention, the tubing comprises through its wall an orifice, or several orifices at the same level. An annular piston, with an internal passage for the fluid, is sealingly mounted to slide in the tubing between a starting position upstream of the orifice (s), to allow fluid to enter the tubing through these ports. ci, and another stop position in which it closes the orifices.

On the upstream side, the annular piston may comprise a valve seat adapted to receive a valve, preferably a ball, intended to close at least one important passage for the fluid in the tubing in the upstream direction downstream, and to release this passage in the opposite direction. At least one bypass, of reduced cross section relative to that of said passage, can be arranged in a bypass of the valve seat and the valve.

According to one particular embodiment, the assembly of the invention may comprise a known system for measuring the orientation in the ground of an object equipped with this system, which may be arranged in a guide nose or between this one and the rest of the set of coring or deflected drilling.

Thus, the assembly according to the invention is particularly suitable in the case where a borehole has been drilled and where a log of this hole has been made. In As a function of the data collected by this logging, it may be desired to carry out drilling and / or coring deviated from this hole in particular directions and at particular depths.

According to a particular embodiment of the invention, the actuating means are arranged to receive, as pressurized fluid, a fluid of the drilling fluid or coring type. According to a particularly advantageous embodiment of the invention, the actuating means are arranged to receive, as pressurized fluid, an expansion fluid pressurized by a fluid of the drilling fluid or coring type via a fluid. a separation piston.

Other details and particularities of the invention will emerge from the secondary claims and the description of the drawings which are appended to the present document and which illustrate, by way of nonlimiting examples, particular embodiments of the assembly according to the invention. invention. An assembly is represented by sections in successive figures which, starting for example from the front end of the assembly, are to be placed one after the other, the top of the one being followed by the down the next. The various figures are elevational views with, where appropriate, breaks and / or partial axial cuts.

la figure 1

une extrémité antérieure d'un ensemble suivant l'invention, comportant en particulier un dispositif dilatable,

la figure 2

un tronçon suivant comportant un élément de guidage et son canal de déviation, ainsi qu'une tubulure amovible,

la figure 3

un tronçon suivant comportant l'élément de guidage, ladite tubulure, la couronne et un tube extérieur de carottier,

la figure 4

un tronçon suivant de l'élément de guidage avec ladite tubulure et le tube extérieur, et à

la figure 5

un tronçon suivant comportant l'extrémité postérieure des élément de guidage et tubulure, ainsi que le tube extérieur.

For an assembly assembled to be lowered into a borehole, it is represented in

Figure 1

an anterior end of an assembly according to the invention, comprising in particular an expandable device,

Figure 2

a next section comprising a guide element and its deflection channel, and a removable tubing,

Figure 3

a next section comprising the guide element, said pipe, the crown and an outer tube of corer,

Figure 4

a next section of the guide element with said tubing and the outer tube, and

Figure 5

a next section comprising the rear end of the guide elements and tubing, and the outer tube.

la figure 6

l'extrémité antérieure de l'ensemble suivant l'invention, comportant en particulier le dispositif dilatable,

la figure 7

le tronçon suivant comportant l'élément de guidage et son canal de déviation,

la figure 8

un tronçon suivant comportant l'élément de guidage, la couronne, un tube extérieur et un tube intérieur de carottier,

la figure 9

un tronçon suivant avec l'élément de guidage et les tubes extérieur et intérieur de carottier, et à

la figure 10

un tronçon suivant avec l'extrémité postérieure des élément de guidage et tube intérieur, le tube extérieur se prolongeant au delà du haut de cette figure.

For the same assembly assembled for a deviated coring in the borehole, it is represented at

Figure 6

the front end of the assembly according to the invention, comprising in particular the expandable device,

Figure 7

the next section comprising the guide element and its deflection channel,

Figure 8

a next section comprising the guide element, the ring, an outer tube and an inner core tube,

Figure 9

a next section with the guide element and the outer and inner cores tubes, and

Figure 10

a next section with the rear end of the guide member and inner tube, the outer tube extending beyond the top of this figure.

la figure 11

un tronçon avec l'élément de guidage et l'extrémité antérieure du carottier équipé d'un bouchon de forage au lieu d'un tube intérieur,

la figure 12

un tronçon suivant avec l'élément de guidage, le tube extérieur et une barre prolongeant ledit bouchon, et à

la figure 13

un tronçon suivant avec l'extrémité postérieure des élément de guidage et barre de prolongation.

For the same set again, but for a deviated drilling in the borehole, it is shown at

Figure 11

a section with the guide element and the front end of the corer equipped with a drill plug instead of an inner tube,

Figure 12

a next section with the guide member, the outer tube and a bar extending said plug, and

Figure 13

a next section with the rear end of the guide members and extension bar.

Figure 14 shows in a view similar to that of Figure 3 but on a larger scale an arrangement of a piston sliding in the removable tubing.

Figures 15 to 18 show an alternative embodiment according to the invention of an assembly for coring or drilling deflected, in a surface position, before descent into the borehole.

Figures 19 to 22 show this variant in the swelling position of the expandable device.

Figures 23 to 26 show this variant after deflation of the expandable device.

In the various figures, the same reference notations designate identical or similar elements.

According to the invention, the coring or deflected drilling assembly comprises (FIGS. 1 to 5) a guide element 1 whose outer diameter is chosen so as to be able to enter the borehole (not shown) to a desired depth for the deviated coring. The guide element 1 has from a rear end 3, in a direction of advance S coring or drilling to the bottom of the borehole, a coaxial internal space 5 of a diameter adapted to accommodate a corer 7.

An expandable device 9 is attached to the forward end 11 of the guide member 1 and has an outer side surface 13 which, in a rest state (shown in Fig. 1), has a smaller cross section than the hole probe and which is arranged to take, in an expanded state of the device 9, an immobilization support against the wall of the borehole. The expandable device 9 includes selective actuating means 15 which are arranged to receive a fluid under pressure which causes expansion of the expandable device 9 beyond a predetermined pressure. The expandable device 9 further comprises a check valve (not shown in this embodiment) arranged to oppose automatically an output of this fluid at a predetermined pressure of said actuating means 15. The fluid under pressure can be particularly coring / drilling fluid, known in the art, brought so far through a drill string 17 (Figure 5) to which all aforesaid is connected during use.

The expandable device 9 may comprise, for the abovementioned immobilization support, a sleeve 18 made of a waterproof elastic material arranged in said device 9, so as to be inflated by the aforementioned fluid pressurized and thus to take a firm hold against the wall of the borehole. During a release of the pressure, the sleeve 18 can then resume its original shape and release its immobilization support.

A deflection channel 19 is hollowed in the guide element 1 in extension and downstream of the internal space 5, upstream of the expandable device 9 along said direction of advance S. The deflection channel 19, including a rear end 21 is coaxial with said inner space 5, has a bottom 23 and two lateral sides 25 which follow, from this rear end 21 and towards the expandable device 9, a direction inclined with respect to the longitudinal axis 27 of the element 1. Said bottom 23 intersects this axis 27. The channel 19 extends to fully open the guide member 1, on the other side of the longitudinal axis 27, at an angle to the aforesaid wall which is chosen for the deviated coring. The deflection channel 19 has a cross section adapted to allow said core core 7 to pass through the bottom 23 and the sides 25.

A longitudinal cavity 29 is cut in the guide element 1, parallel to the aforementioned longitudinal axis 27, and is arranged to allow passage from the aforesaid internal space to the actuating means 15 of the expandable device 9. Preferably, this longitudinal cavity 29 and the guide element 1 are coaxial.

In the inner space 5 of the guide element 1, possibly even in a rear portion 31 of the deflection channel 19, there is arranged an outer tube 33 of the corer 7 aforesaid. This outer tube 33 comprises a coring ring 35 fixed to the front end of this outer tube 33, is to be suspended from a drill string 17, and is releasably locked in the guide element 1, in particular of so that the ring 35 is included inside the imaginary outer casing of the guide member 1. The outer tube 33 can be worn (Figures 4 and 5) by two bearing bushes 36 so as to be able to after having been released, rotate and slide in the internal space 5 and in the deflection channel 19 and then progress in the formation.

In the outer tube 33 of the corer 7, to actuate the expandable device 9, there is temporarily disposed a removable tubing 39 which extends from the inside of the outer tube 33, through the longitudinal cavity 29, to the means of 15. The removable tubing 39 has a rear end 41 open to allow the pressurized fluid from the drill string 17 to pass therethrough. A hooking piece 43 is attached to this rear end 41 and is arranged for subsequent withdrawal. tubing 39 out of the above set. An anterior end 45 of said tubular 39 is arranged for a releasable and sealed connection between the tubing 39 and the selective actuating means 15 for communicating thereto, through said tubing 39, the aforementioned fluid pressure. For example, the tubing 39 (FIG. 1) is driven into a through-hole 47 of the expandable device 9, two O-rings 49 sealing between the tubing 39 and the device 9.

In this same outer tube 33, after having expanded the expansion device 9 and having said tubing 39 removed from the assembly, it is possible to have either a conventional inner tube 51 (FIGS. 8 to 10) for the corer 7 or a plug 53 of drilling (Figures 11 to 13) which completes the ring 35 to form a drill head. At its anterior end which can project from the crown 35, the plug 53 is then equipped with knives or abrasive elements. The inner tube 51 and the cap 53 also each have an attachment piece 43 each fixed at their rear end and arranged for their descent into, or subsequent withdrawal from, the aforesaid assembly.

To fix them to one another, the guide member 1 may comprise (Figure 1) a sliding member 55 and the expandable device 9 may include a chamber 57 in which the sliding member 55 is guided and can slide between two stop positions, a position (shown) in which the sliding member 55 closes an outlet 59 of the fluid contained under the pressure determined in the expandable device 9 expanded and a position (not shown) in which the sliding member 55 opens this outlet passage 59.

The outer tube 33 may comprise an outer bearing face 61 (FIG. 3) facing upstream and intended to cooperate with an internal abutment face 63 (FIG. 4) that comprises the guide element 1, which is turned towards downstream and against which can abut the bearing face 61 when said outer tube 33 is pulled out of the borehole.

In addition, the outer tube 33 may advantageously be releasably secured in the guide element 1 by a pin 65 (FIG. 3) calibrated to break during a controlled rotation and / or translation movement of the outer tube 33 in the guide member 1 attached to the wall of the borehole by the expandable device 9 expanded.

To be used, the deflected core / drill assembly that has just been described is first assembled, equipped with the removable tubing 39 according to FIGS. 1 to 5, and is attached to a drill string 17 via The assembly is then lowered into the borehole and rotated if necessary (see below), acting on the drill string 17, so that the deflection channel 19 has its opening in the direction in which it is desired to carotter or drill deviated. The fluid sent from the surface, through the drill string 17 (FIG. 5), passes into the outer tube 33 and, by an annular space between the latter and the posterior end 41 of the tubing 39, this fluid arrives in tubing 39 through openings 67 therein provided. A soft metal seal ring 69 may be provided between the tubing 39 and the outer tube 33 and prevent said fluid from escaping from the described path. The fluid arrives (Figure 1) at the anterior end 45 of the tubing 39 and, at an adequate pressure, inflates the sleeve 18 so that it is firmly pressed against the wall of the borehole. When the pressure is then reduced, the check valve (not shown in this embodiment) prevents the sleeve 18 from deflating. The guide element 1 is thus immobilized in the borehole. The removable tubing 39 can then be removed from the outer tube 33, in a known manner known as "wire line" in the loom, by means of its attachment piece 43 through the drill string 17. to the surface.

If it is then desired to core, the inner tube 51 (Figures 7 to 10) can be lowered into position in the outer tube 33 by the same technique of "wire line". The inner tube 51 may be held in place, abutting near or in the ring 35 by the pressure of the fluid generally supplied for coring purposes. To start the deviated coring, it is first necessary to break the releasable locking, in particular by rotating the outer tube 33, with the aid of the drill string 17, in the guide element 1 fixed to the wall of the borehole as explained above. This rotation, or a translational movement communicated to the outer tube 33 with or without shock, breaks the pin 65 calibrated for this purpose. The corer 7 controlled, driven in rotation and pushed through the drill string 17, is guided by the guide member 1 to attack the wall of the borehole at the desired angle.

If it is desired to make a deviated drilling in the direction set, either before a deviated coring, or without consecutive coring, or again after coring deviated in this direction, is installed in the outer tube 33, instead of the inner tube 51, said plug 53 (Figures 11 to 13) using the same technique of the "wire line". Said plug 53 may comprise (FIG. 11), in a bar 73 which composes it, a latch 75 which is pushed to a stop by a spring 77 in a position projecting from the bar 73 and which can be pushed back into a retracted position in said bar 73 by an external action. The latch 75 has at each of its anterior and posterior ends an inclined pan arranged so that, when the plug 53 is inserted into the outer tube 33 or removed from it, said latch 75 automatically retracts into the bar 73.

A longitudinal groove 79 is cut in the inner wall of the outer tube 33 so as to receive the latch 75, which engages under the thrust of the spring 77. This can occur at the end of the descent of the plug 53 in the outer tube 33 when the latch 75 is in alignment with the groove 79. Otherwise, when the latches 75 and groove 79 are not aligned while the plug 53 is in place in the ring 35, this occurs because it There is a possible relative rotation between the plug 53 and the outer tube 33 as soon as they come into contact with the material to be drilled. The cooperation of the lock 75 and the groove 79 causes the coordinated rotation of the drill plug 53 by the outer tube 33 which drives the crown 35 in the same way.

It may be noted (FIG. 11) at the level where the housing of the lock 75 is located, one or more longitudinal ducts 80 drilled in the wall of the outer tube. 33, parallel to the longitudinal axis 27 and open only at their ends so as to prevent said latch 75 can hook.

In the embodiment shown, the cap 53 is pushed longitudinally in downstream support, for example against an inner annular face 81 (Figure 13) of the outer tube 33, by the pressure of the drilling fluid passing therethrough.

It is noted in Figures 13 to 11 that the bar 73 may be hollow between the attachment piece 43 and the housing of the lock 75 and have inlet and outlet ports so that fluid can flow from upstream to the 'downstream. Another tubular section may be provided in said bar 73 between the housing of the latch 75 and the front end of the plug 53. Slots 82 (FIG. 11) may be drilled in the front end of the plug 53 to provide for front nozzles. 83 of the fluid from the annular space provided between the drill plug 53 and the outer tube 33.

In one embodiment of the invention, the tubing 39 may comprise (FIGS. 3 and 14) through its wall an orifice 87, or several orifices 87 at the same level. An annular piston 89, having an internal passage for the fluid, is then sealingly mounted to slide in said tubing 39 between a starting position (shown in FIGS. 3 and 14) upstream of the orifices 87, in order to allow to fluid entering through the tubing 39, and another position (not shown) abutting downstream, wherein the same piston 89 closes the orifices 87, the fluid being channeled then through the annular piston 89.

Associated with the annular piston 89, a valve seat 95 is arranged to receive a valve 97. This may preferably be a ball 97 installed at the assembly or throwing through the drill string 17, and is intended for closing at least one major section of the passage for the fluid in the removable tubing 39 in the upstream direction downstream, and to release this passage in the opposite direction. To ensure a desired reduced passage from upstream to downstream, it can be formed, for example in the valve seat 95, at least one bypass 98, of reduced cross section relative to that of said passage, which is arranged in a bypass of the valve seat 95 and the valve 97.

When the assembly described above, comprising said removable tubing 39, is lowered into the borehole, fluid contained in this hole must be able to escape towards the surface without causing a force capable of dislodging the tubing 39 from its mounting position in the assembly. When the orifices 87 are open as shown, fluid can enter through these into the tubing 39 and back to the surface without unduly pushing the tubing 39 to the surface. When the assembly is disposed in a deviated drilling / coring position, it suffices to give a predictable pressure stroke at a desired moment for the annular piston 89 to be pushed from its represented starting position to its abutment position. downstream, in which it closes the orifices 87 to force the fluid to go to the selective actuation means 15 to inflate the sleeve 18.

The passage through the annular piston 89 to be relatively large to effectively pass the downstream fluid upstream as explained above, the aforementioned pressure stroke for moving the piston 89 may have to be exaggeratedly large, d an undesirable level. To achieve a safe displacement of the annular piston 89 at a reasonable pressure, the valve or ball 95 aforesaid is used. It then closes said passage from upstream to downstream and offers the fluid a larger surface, so that the annular piston 89 is pushed effectively, by the combination with the ball 95, in its closed position of the orifices 87 The bypass (s) 98 allow fluid to flow however from upstream to downstream to actuate the expandable device 9.

Advantageously, the annular piston 89 is held in said starting position by a breakable element 91, such as a pin, calibrated to break under a thrust of the piston 89 subjected to a pressure beyond a given threshold.

It should be understood that the invention is in no way limited to the described embodiments and that many modifications can be made thereto without departing from the scope of the claims.

Thus, to prevent longitudinal movement of the removable tubing 39 in the outer tube 33, it can be provided, for example on the upstream side of the tubing 39, a positioning stopper 99 (FIG. 5), in particular combined with the ring 69. which can bear against a suitable surface provided in the outer tube 33. It is also possible to adapt a releasable latch 100, in particular to two bolts 101, which is mounted on the pipe 39, the two bolts 101, shaped accordingly, are automatically locked by the action of a spring 103 in longitudinal notches 105 or other receptacles cut into the outer tube 33. During a given traction on said attachment piece 43 to remove the tubing 39 of the outer tube 33, the two bolts 101 are removed from the notches 105 in a known manner.

As shown in Figures 1 and 6, in front of the expandable device 9 may be arranged a guide nose 107 whose anterior end is preferably hemispherical.

A known system, not shown, for measuring the orientation in the ground of an object equipped with this system can be interposed for example in said guide nose 107 or between the latter and the remainder of the coring assembly or deviated drilling. This measurement system can be of the type that records data, then accessible after bringing the assembly and the system back to the surface, or of the type that transmits orientation data in real time to an operator on the surface. Depending on the coring material used, the operator can optionally use these data transmitted in real time, so as to act on all and give it a particular orientation for drilling and / or coring.

In another embodiment, said orientation measuring system can be associated with the removable tubular 39, preferably at its posterior end 41. This system can be attached to it and then it is reassembled only after inflation. elastic sleeve 18 and either it has transmitted in real time data on the orientation of the guide member 1, or the data is taken from the system once brought to the surface. Based on these orientation data of the assembly as it has been positioned in the borehole, a deviation from a desired orientation can be deduced therefrom and the orientation accordingly changed by acting on the train. rods.

In yet another variant, said measurement system can be detachably associated with the rear end 41 of the removable tubing 39 and be brought up to the surface as many times as necessary, before inflating the elastic sleeve 18, in order to take the recorded orientation information and check that the orientation of the assembly is good or correct it accordingly.

In either case, after having equipped said assembly of the aforementioned system, and before descending the whole in the borehole, one can make a calibration of said system to univocally know its orientation relative to that of the channel deflection 19 for example and to be able to set the orientation of this channel in a safe manner.

It would also be preferable, for the inflation operation, a particular fluid, without solid particles, to ensure a faultless operation of the check valve. This particular fluid could be sent under pressure through the drill string 17 or stored in the above set and pressurized to using a coring / drilling fluid acting in particular on a piston 20 for separating the two fluids.

A coring or drilling set allowing this operation is illustrated in FIGS. 15 to 23.

In Figures 15 to 18, the assembly according to the invention is at the surface, before the descent into the borehole. The guide nose 107 of this installation comprises a supply pipe 108 which opens at one end to the outside and can be closed there by a tap 109. In the position illustrated in FIG. 15, the tap 109 is open, which allows a supply of a fluid without particles, for example water, in the pipe 108 which communicates with an annular cavity 110, provided inside a support cylinder 111 of the expandable device 9. This annular cavity 110 communicates in turn with a cylindrical cavity 112, in the upstream part of which, in the direction of descent of the drilling assembly, is arranged a check valve 22. This valve comprises a first portion 113 and a second portion 114 capable of to perform a reciprocal sliding movement.

In the position shown in Figure 17, the valve 22 is in the up position. The second portion 114, under its own weight, bears on a seat 115 of the first portion 113 and thus releases an annular passage 116 between the first portion 113 and the second portion 114 of the valve 22. In this position, the valve 22 allows a passage of the fluid supplied from the cylindrical cavity 112 to the cylindrical chamber 117 in which the separation piston 20 is arranged.

In the position illustrated in FIG. 18, the fed fluid exerts an upward pressure on one of the surfaces of the piston 20, while the other surface is at atmospheric pressure, since no fluid has yet been injected into the train of tubes. The piston is thus driven upwards as soon as the product of this pressure by the first surface of the piston overcomes the friction resistance of the joints between the piston 20 and the outer wall 118 of the chamber 117.

In the high position, the piston 20 can abut against the stop 119 and even cause detachment of the non-return valve 120 thus allowing a purge of the lower compartment of the chamber 117.

As can be seen in FIG. 16, the annular cavity 110 has outlet ducts 131 oriented radially towards the inner lateral surface 12 of the expandable device. However the pressure applied to the liquid fed, which will serve as expansion fluid is not sufficient to overcome the inherent resistance of the expandable device 9 to expansion.

In Figures 19 to 22, the assembly according to the invention has been lowered into the borehole and the expandable device 9 is being dilated.

The tap 109 has been closed.

As can be seen in FIG. 22, the removable tubing 39, as described in the embodiment illustrated in FIGS. 1 to 14, is pressed in a sealed manner into one end of a tubular throttling element 121. at its end, this throttling element 121 is provided with a restrictor 122 which puts the throttle cavity in communication with the borehole through an outlet conduit 123 and which causes an upstream pressure increase.

Upstream of the choke, in the direction of flow of the drilling fluid fluid supplied by the removable tubing 39, the throttling element 121 is provided with small orifices 124 which are directed radially outwardly and allow thus, a portion of the drilling or coring fluid is fed into the compartment of the chamber 117 which is opposite to that receiving the dilation fluid.

The throttling element 121 thus separates the pressurized drilling fluid into two streams, a high flow main stream which is discharged into the borehole and a low flow secondary stream which acts to act on the separating piston. When the product of the pressure of the drilling fluid through the surface of the separation piston 20 is greater than the sum of the product of the expansion fluid pressure by the area of the separation piston 20 and the friction of the separation piston 20 over the inner wall 118 of the chamber 117, the piston is moved downwards.

In the low position, the piston 20 bears against the abutment 125.

In the lower position of the drilling or coring assembly according to the invention, the second portion 114 of the check valve 22 has been immobilized in the borehole by known means. The first part 113 is then slid down into the second part 114, and, as illustrated in FIG. 21, the first part 113 in the low position bears on the seat 126 of the tubular part 114. In this position, the valve 22 closes any passage of expansion fluid from the cylindrical cavity 112 to the chamber 117 of the separation piston 20.

In this position also, the radial holes 132 provided in the second portion 114 of the check valve 22 are housed in front of the holes radial means 133 of a support tube 134 of the first portion 113 of the valve 22. By known means, shear screws are then passed through these holes 132 and 133 so as to immobilize any movement of the second portion 114 relative to to the rest of the drilling and coring set and thus also to the first part 113.

Since the pressure of the drilling or coring fluid is high, the pressure of the expansion fluid in the chamber 117 becomes such that it drives down the ball 127 of the non-return valve integrated in the check valve 22, Against the return spring 129. An expansion fluid passage is then allowed from the chamber 117 of the separation piston 20 to the cylindrical cavity 112, where the pressure increases correspondingly. At a time, the pressure exceeds the determined pressure to overcome the resistance of the expandable device 9. As shown in Figure 20, the expandable device is then expanded, which allows immobilization of the assembly according to the invention to the inside the borehole.

At a given moment, the pressure increases in the chamber 117 to the point that a safety valve 130 breaks and gives access to the outside fluid to the upper compartment of this chamber (see Figure 26). The supply of pressurized drilling fluid could then be stopped or maintained for the purpose of cleaning the borehole. The expandable device 9 is, in the meantime, held in its expanded position, with no possibility of upward return of the expansion fluid, which is prevented by the check valve 22 and the ball 127 of its non-return valve.

In the position shown in Figures 23 to 26, the expandable device must be deflated to allow movement, in particular a rise, of the drilling or coring assembly according to the invention in the borehole.

The supply of drilling or coring fluid is stopped and the removable tubing 39 (see Fig. 22) is unhooked and raised (see Fig. 26).

A pull is also exerted upward on the support tube 134 of the first portion 113 of the check valve 22. This pull is sufficient to shear the screws 135, as shown in FIG. 25. The second portion 114 of the valve 22 is then released and can slide in its lower position, which again releases a passage 116 of the cylindrical cavity 112 to the cylindrical chamber 117 (as described with reference to Figure 17).

The product of the expansion fluid pressure from the surface of the separation piston 20 then becomes greater than the sum of the product of the pressure of the drilling or coring fluid remaining in the upper compartment of the chamber 117 by the surface of the piston of the separation and friction of the piston 20 against the outer wall 118 of this chamber 117. The piston 20 slides upwards and the expandable device 9 returns by elastic return in its initial position in application on the support cylinder 111, which allows the desired movement of the drilling or coring assembly.

This last drilling or coring assembly according to the invention, as illustrated in FIGS. 15 to 26, has the advantage of using at the level of the check valve and the expandable device of a clean fluid, it is i.e. without suspended particles which are a source of fouling of the check valve. Moreover, the division of the stream of drilling fluid under pressure into a main stream and a low flow secondary stream makes it possible to act in a controlled manner on the separation piston, and therefore on the expansion device, without taking into account the flow rate of the fluid. drilling. Separate pumping of drilling fluid during the expansion operation is not required, pumping installations required for drilling or coring may be used.

Legend of figures

S

sense of advance of coring / drilling

1

guiding element

3

posterior end of 1

5

internal space of 1

7

corer

9

expandable device

11

front end of 1

13

external side surface of 9

15

means of selective actuation of 9

17

string of stems

18

sleeve of 9

19

diversion channel in 1

20

separation piston

21

posterior end of 19

22

check valve

23

background of 19

25

side sides of 19

27

longitudinal axis of 1

29

longitudinal cavity in 1

31

posterior portion of 19

33

outside tube of 7

35

coring ring of 7

36

bearing bushes

39

removable tubing

41

posterior end of 39

43

attachment piece 39, 51, 53,

45

anterior end of 39

47

passage hole of 9

49

O-rings of 9

51

inner tube of 7

53

drilling plug for 35

55

sliding organ

57

room for 55

59

fluid outlet passage of 9

61

external support surface of 33

63

internal stop face of 1

65

calibrated spindle, between 33 and 1

67

openings in 39

69

sealing ring between 33 and 39

73

53 bar

75

lock of 53

77

spring of 73

79

longitudinal groove in 33

80

duct or longitudinal ducts in 33

81

inner annular support surface of 33

82

passages in 53

83

front nozzles of 53

87

orifice (s) in 39

89

annular piston in 39

91

breakable element

95

valve seat in 39

97

valve / ball

98

bypass 95

99

positioning stop 39

100

releasable lock 39

101

bolts of 100

103

spring of 100

105

longitudinal notches in 33 percent

107

guiding nose

108

supply line

109

tap

110

annular cavity in 111

111

support cylinder of 9

112

cylindrical cavity

113

first part of 22

114

second part of 22

115

support seat for 113

116

ring passage

117

cylindrical chamber receiving 20

118

outer wall of the chamber 117

119

stop

120

check valve

121

throttling element

122

Strangler

123

outlet duct

124

radial holes in 121

125

stop

126

support seat for 113

127

ball of 128

128

check valve

129

127 spring return

130

safety valve

131

radial outlet ducts of 110

132

radial holes of 114

133

radial holes of 134

134

113 support tube

135

shear bolts

Claims (16)

1. Assembly intended for sidetracked coring or drilling, in a wall of a borehole previously drilled or cored in a formation, the assembly comprising:

   - a guide element (1)

   - with an outside diameter chosen so as to be able to enter the borehole to a required depth for the side-tracked coring, and

   - having, from a posterior end (3), in a direction of advance (S) of the coring or drilling towards the bottom of the borehole, a coaxial internal space (5) with a diameter adapted to house a core barrel (7) therein,

   - an expansible device (9)

   - fixed to the front end (11) of the guide element (1),

   - having an external lateral surface (13) which, in an idle state, has a transverse section less than that of the borehole and which is arranged to take, in an expanded state of the device (9), immobilisation abutment against the wall of the borehole, and

   - comprising selective actuation means (15) arranged to receive a pressurised fluid which causes an expansion of the expansible device (9) beyond a given pressure, and a valve so arranged as to automatically oppose a discharge of this fluid at a given pressure from the said actuation means (15),

   - a sidetracking channel (19) hollowed out in the guide element (1) in line with the internal space (5), upstream of the expansible device (9) in the said direction of advance (S), the sidetracking channel (19) having

   - a posterior end (21) coaxial with the said internal space (5),

   - a base (23) and lateral sides (25) which follow, from this posterior end (21) of the channel (19) and in the direction of the expansible device (9), a direction inclined with respect to the longitudinal axis (27) of the guide element (1), the base (23) intercepting this axis (27), the channel (19) extending until it opens out entirely from the guide element (1), on the other side of the longitudinal axis (27), at a angle, with respect to the above mentioned wall, chosen for the sidetracked coring, and

   - a transverse section adapted so that the said core barrel (7) guided by the base (23) and the sides (25) can pass therein,

   - a longitudinal cavity (29) cut in the guide element (1) parallel to the aforementioned longitudinal axis (27) and arranged to allow passage from the above mentioned internal space (5) as far as the actuation means (15) of the expansible device (9),

   - in the internal space (5) of the guide element (1), possibly even in a posterior portion (31) of the sidetracking channel (19), an external tube (33) of the above mentioned core barrel (7)

   - comprising a core bit (35) fixed to the front end of this external tube (33),

   - to be suspended from a drill string (17), and

   - releasably locked in the guide element (1), in particular so that the bit (35) is included within an imaginary external envelope of the guide element (1),

   - arranged so as to be able to slide, after having been released, in the internal space (5) and in the sidetracking channel (19) and then progress in the formation,

   - in the external tube (33) of the core barrel (7), temporarily disposed so as to actuate the expansible device (9), a removable tubing (30) which extends from the inside of this external tube (33), through the longitudinal cavity (29), as far as the selective actuation means (15), and which comprises

   - a posterior end (41) open so as to allow the pressurised fluid coming from the drill string (17) to pass therein,

   - an attachment piece (43) fixed to this posterior end (41) and arranged for a subsequent withdrawal of the tubing (39) out of the above mentioned assembly,

   - a front end (45) arranged for releasable and sealed connection between the tubing (39) and the selective actuation means (15) with a view to communicating to the latter, through the said tubing (39), the pressurised fluid, and

   - in this same external tube (33), after having expanded the expansible device (9) and having withdrawn the said tubing (39) out of the assembly, either an internal tube (51) of the core barrel or a core bit top (53) arranged so that the latter can drill, the internal tube (51) or the bit top (53) having an attachment piece (43) fixed to its posterior end and arranged for its descent and subsequent removal out of the above mentioned assembly.
2. Coring or drilling assembly according to Claim 1, characterised in that, for their mutual fixing, the guide element (1) comprises a sliding member (55) and the expansible device (9) comprises a chamber (57) in which the sliding member (55) can slide between two stop positions, a position in which the sliding member (55) closes off a discharge passage (59) for the fluid contained at the given pressure in the expanded expansible device (9) and a position in which this member (55) opens up this discharge passage (59).
3. Coring or drilling assembly according to one or other of Claims 1 and 2, characterised in that the external tube (33) of the core barrel (7) comprises an external abutment face (61) turned towards the upstream side and intended to cooperate with an internal stop face (63) which the guide element (1) has, which is turned downstream and against which the abutment face (61) comes to abut when the said external tube (33) is drawn out of the borehole.
4. Coring or drilling assembly according to any one of Claims 1 to 3, characterised in that the external tube (33) of the core barrel (7) is held fixed in a releasable manner in the guide element (1) by a pin (65) calibrated so as to break, during a controlled rotation and/or translation movement of the external tube (33) in the guide element (1) fixed to the wall of the borehole by the expanded expansible device (9).
5. Coring or drilling assembly according to any one of Claims 1 to 4, characterised in that

   - the tubing (39) comprises an orifice (87), or several orifices (87) at the same level, through its wall,

   - an annular piston (89) with an internal passage for the fluid, is mounted sealingly so as to slide in the tubing (39) between a starting position upstream of the orifice or orifices (87), in order to enable fluid to enter the tubing (39), and another stop position in which it closes off the orifice or orifices (87), the fluid being channelled through the annular piston (89).
6. Coring or drilling assembly according to Claim 5, characterised in that the annular piston (89) is held in the said starting position by a breakable element (91) calibrated so as to break under a thrust of the piston (89) subjected to a pressure beyond a given threshold.
7. Coring or drilling assembly according to one or other of Claims 5 and 6, characterised in that the tubing (39) comprises

   - associated with the said annular piston (89), on the upstream side, a valve seat (95) adapted to be able to receive a valve (97), preferably a ball (97), intended to close off at least one large passage full of fluid in the tubing (39) in the direction from upstream to downstream, and to leave this passage clear in the opposite direction,

   - at least one bypass (98), with a transverse section reduced with respect to that of the said passage, arranged as a bypass for the valve seat (95) and the valve (97).
8. Coring or drilling assembly according to any one of Claims 1 to 7, characterised in that it comprises, for preventing a longitudinal movement of the tubing (39) in the said external tube (33)

   - towards the downstream, a positioning stop (99) and

   - towards the upstream, a releasable bolt (100) which is mounted on the tubing (39), which is automatically locked in the external tube (33) and which is connected to the attachment piece (43) of the tubing (39) so that it is released when there is a given traction on the said attachment piece (43).
9. Coring or drilling assembly according to any one of Claims 1 to 8, characterised in that, in front of the expansible device (9) there is arranged a guide nose (107) whose front end is preferably hemispherical.
10. Coring or drilling assembly according to any one of Claims 1 to 9, characterised in that it comprises a system for measuring the orientation in the ground of an object equipped with this system, the latter being able to be of the type which records orientation data which can be analysed after having returned the system to the surface and/or of the type which transmits these data in real time to the surface during the operation in the borehole.
11. Coring or drilling assembly according to Claim 10, characterised in that the said measuring system can be disposed in the guide nose (107) or between this and the rest of the sidetracked coring or drilling assembly.
12. Coring or drilling assembly according to Claim 10, characterised in that the said measuring system can be associated with the removable tubing (39), preferably at the posterior end (41) of this tubing (39).
13. Coring or drilling assembly according to any one of Claims 1 to 12, characterised in that the actuation means (15) are arranged so as to receive, as a pressurised fluid, a fluid of the drilling or coring fluid type.
14. Coring or drilling assembly according to any one of Claims 1 to 12, characterised in that the actuation means (15) are arranged so as to receive, as a pressurised fluid, an expansion fluid pressurised by fluid of the drilling or coring fluid type by means of a separation piston (20).
15. Coring or drilling assembly according to Claim 14, characterised in that it comprises a throttling element (121) in which the removable tubing (39) opens out and which puts the fluid of the drilling or coring fluid type under pressure and divides it into a main flow passing through the throttling element (121) towards the inside of the borehole and secondary stream, with a lower flow rate than the main stream, which serves as a pressurised fluid capable of pressurising the expansion fluid.
16. Coring or drilling assembly according to Claim 15, characterised in that the separation piston (20) slides in a sliding chamber (117) of the above mentioned actuation means between two extreme positions and has a first surface which comes into contact with the fluid of the drilling or coring fluid type and a second surface which comes into contact with the expansion fluid, in that the separation piston (20) slides in a first direction towards one of the above mentioned two extreme positions when the product of the pressure of the expansion fluid multiplied by the above mentioned second surface area is greater than the sum of the product of the pressure of the fluid of the drilling or coring fluid type multiplied by the above mentioned first surface and the friction between the separation piston and the sliding chamber (117), in that the separation piston slides in a second direction towards the other one of the above mentioned two extreme positions when the product of the pressure of the fluid of the drilling or coring fluid type and the above mentioned first surface is greater than the sum of the product of the pressure of the expansion fluid multiplied by the above mentioned second surface area and the friction between the separation piston and the sliding chamber, and in that, during the sliding of the separation piston (20) in the first direction, the expansion fluid does not attain the said given pressure beyond which an expansion of the expansible device (9) takes place, whilst, during the sliding of the separation piston (20) in the second direction, the expansion fluid attains the said given pressure and causes an expansion of the expansible device (9).

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