EP1570150A1

EP1570150A1 - One-step directional coring or drilling system

Info

Publication number: EP1570150A1
Application number: EP03747752A
Authority: EP
Inventors: Philippe R. Fanuel; Luis E. Quintana; Olivier Mageren
Original assignee: Halliburton Energy Services Inc
Current assignee: Halliburton Energy Services Inc
Priority date: 2002-09-26
Filing date: 2003-09-25
Publication date: 2005-09-07
Anticipated expiration: 2023-09-25
Also published as: CA2499725C; US7117958B2; DE60309925D1; WO2004029401A1; ATE346218T1; EP1570150B1; NO20051890L; BE1015123A3; CA2499725A1; US20050167158A1; US7320373B2; US20070017707A1

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

CORING SYSTEM OR DRILLING DEVIED TO A PASS

The present invention relates to an assembly intended for coring or deviated drilling, in a wall of a borehole drilled or cored beforehand in a formation. There are many assemblies intended for this kind of work but those that are known to date require a prior operation of positioning the guide element or deflection, separately from the operation of lowering the core barrel and d use of it. This succession of operations takes a lot of time which, as we know, is very expensive in this profession due to the special specialization of the individuals who practice it, the risks they run, the specific equipment used, the technical complexity operations which must be carried out, etc. There is in addition the risk of losing expensive equipment in the ground with each operation of descent and ascent and, often because of this, of losing in addition the access to the borehole . In order to avoid a maximum of these risks, and to save operating time, the present invention aims to propose an assembly with which the guide or deflection element and the core barrel are lowered in one operation.

For this purpose, the deviated coring or drilling assembly of the invention comprises a guide element whose external diameter is chosen to be able to enter the borehole to a depth desired for the deflected coring, and which has at 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 suitable for housing a corer there.

An expandable device, fixed to the front end of the guide element, has an external lateral surface which, in a state of rest, has a cross section smaller than that of the borehole and which is arranged to take, in a expanded state of the device, an immobilization support for 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 expandable device beyond a determined pressure of the fluid, and a valve arranged to automatically oppose an outlet of this fluid at a pressure determined outside said actuating means. A deflection channel is hollowed out in the guide element in extension of the internal space, upstream of the expandable device in said direction of advance. The deflection channel has a rear end coaxial with said internal space, a bottom and lateral sides which follow, from this rear end of the channel and in the direction of the expandable device, a direction inclined with respect to the longitudinal axis of the guide element, the bottom intersecting this axis. The channel extends until it opens completely from the guide element, on the other side of the longitudinal axis, at an angle relative to the above wall which is chosen for the deflected coring. The deflection channel has a cross section suitable for passing said corer guided by the bottom and the sides.

A longitudinal cavity is cut in the guide element parallel to the aforementioned longitudinal axis, and is arranged to allow passage from the said internal space to the actuating means of the expandable device. In the internal space of the guide element, possibly even in a rear portion of the deflection channel, there is arranged an outer tube of the aforementioned core barrel. This outer tube comprises a coring ring fixed to the front end of this outer tube, is to be suspended from a drill string, and is releasably locked in the guide element, in particular so that the crown is included inside an imaginary outer envelope of the guide element. The outer tube is arranged to be able to slide, after being released, into the internal space and into the deflection channel and then progress in the formation.

In the outer tube of the core barrel, temporarily arranged to actuate the expandable device, there is mounted a removable tube which extends from the interior of this outer tube, through the longitudinal cavity, to the selective actuation means. The removable tubing has an open rear end for the passage of pressurized fluid from the drill string. A hooking piece is fixed to this rear end and is arranged for subsequent withdrawal of the tubing from the above-mentioned assembly. A front end of said tubing is arranged for a releasable and sealed connection between the tubing and the selective actuation means in order to communicate to the latter, by said tubing, the fluid under pressure.

In this same outer tube, after having expanded the expandable device and having removed said tubing from the assembly, it is possible to have either an inner core barrel or a crown plug arranged so that it can make drilling, the inner tube or the stopper having a hooking piece fixed at its rear end and arranged for its descent and its subsequent removal from the above-mentioned assembly.

As can be understood by a person skilled in the art on reading the above, the assembly described above, thus assembled, is lowered into a block in the borehole and can be oriented so that the crown attacks the wall of the hole in the desired direction. Only a simple exchange between the removable tubing and either the inner core barrel or the said drilling plug must be carried out before attacking the wall. For their mutual fixing, the guide element can comprise a sliding member and the expandable device can comprise a chamber in which the sliding member can slide between two stop positions, a position in which the sliding member closes an outlet passage. of the fluid contained under the pressure determined in the expanded expandable device and a position in which this member opens this outlet passage. This arrangement allows the fluid to selectively escape from the expandable element at a desired time, so that the latter can be released from the immobilization relative to the wall.

According to one embodiment of the invention, the tubing has 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), in order to allow fluid to enter the tubing through them ci, and another stop position in which it closes the orifice (s).

On the upstream side, the annular piston may include a valve seat adapted to receive a valve, preferably a ball, intended to close at least one large passage for the fluid in the tubing in the upstream to downstream direction, and release this passage in reverse. At least one bypass, of reduced cross section relative to that of said passage, can be arranged in bypass of the valve seat and of the valve. According to a particular embodiment, the assembly of the invention may include a known system for measuring the orientation in the ground of an object equipped with this system, which can be placed in a guide nose or between this and the rest of the deflected core or drill assembly.

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

According to a particular embodiment of the invention, the actuating means are arranged to receive, as pressurized fluid, a fluid of the drilling or coring fluid type. According to a particularly advantageous embodiment of the invention, the actuation means are arranged to receive, as pressurized fluid, an expansion fluid pressurized by a fluid of the drilling or coring fluid type via 'a separation piston. Other details and particularities of the invention will emerge from the secondary claims and from the description of the drawings which are annexed to the present specification and which illustrate, by way of non-limiting examples, particular embodiments of the assembly according to invention. An assembly is represented by sections in successive figures which, starting for example from the anterior end of the assembly, are to be placed one after the other, the top of one being followed by the bottom of the next. The various figures are views in elevation with, if necessary, broken and / or partial axial sections.

For an assembly assembled to be lowered into a borehole, there is shown in FIG. 1 a front end of an assembly according to the invention, comprising in particular an expandable device, FIG. 2 a following section comprising a guide element and its deflection channel, as well as a removable tube, FIG. 3 a following section comprising the guide element, said tube, the crown and an outer core barrel, FIG. 4 a following section of the guide element with said tubing and the outer tube, and in Figure 5 a following section comprising the rear end of the guide element and tubing, as well as the outer tube. For the same assembly assembled for a deflected core drilling in the borehole, it is represented in FIG. 6 the anterior end of the assembly according to the invention, comprising in particular the expandable device, FIG. 7 the following section comprising the guide element and its deflection channel, Figure 8 a following section comprising the guide element, the crown, an outer tube and an inner core barrel, Figure 9 a following section with the guide element and the outer and inner core barrels, and at the 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. For the same assembly again, but for a deflected borehole in the borehole, there is shown in FIG. 11 a section with the guide element and the anterior end of the core barrel equipped with a drilling plug instead of an inner tube, FIG. 12 a next section with the guide element, the outer tube and a bar extending said plug, and in FIG. 13 a next section with the rear end of the guide element 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.

FIGS. 15 to 18 represent an alternative embodiment according to the invention of an assembly intended for coring or deviated drilling, in a surface position, before descent into the borehole.

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

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

In the different figures, the same reference notations designate identical or analogous elements.

According to the invention, the deviated coring or drilling assembly comprises (FIGS. 1 to 5) a guide element 1 whose external diameter is chosen so as to be able to enter the borehole (not shown) to a desired depth for deflected core drilling. The guide element 1 has, from a rear end 3, in a direction of advance S of the coring or drilling towards the bottom of the borehole, a coaxial internal space 5 of a diameter suitable for housing a corer therein. 7. An expandable device 9 is fixed to the front end 11 of the guide element 1 and has an external lateral surface 13 which, in a state of rest (shown in FIG. 1), has a cross section smaller than that of the hole probe and which is arranged to take, in an expanded state of the device 9, an immobilizing support against the wall of the probe hole. The expandable device 9 comprises selective actuation means 15 which are arranged to receive a pressurized fluid which causes expansion of the expandable device 9 beyond a determined pressure. The expandable device 9 further comprises a check valve (not shown in this embodiment) arranged to automatically oppose an outlet of this fluid at a determined pressure from said actuating means 15. The fluid under pressure may in particular be a coring / drilling fluid, known in the art, brought so far through a string of rods 17 (FIG. 5) to which the above-mentioned assembly is connected during its use.

The expandable device 9 may comprise, for the abovementioned immobilization support, a sleeve 18 made of tight elastic material arranged, in said device 9, so as to be able to be inflated by the aforementioned fluid pressurized and thus to take firmly against the wall of the borehole. When the pressure is released, the sleeve 18 can then return to its starting form and release its immobilization support. A deflection channel 19 is hollowed out in the guide element 1 as an 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 one rear end 21 is coaxial with said internal space 5, has a bottom 23 and two lateral sides 25 which follow, from this rear end 21 and in the direction of the expandable device 9, a direction inclined relative to the longitudinal axis 27 of the element guide 1. Said bottom 23 intersects this axis 27. The channel 19 extends until it opens entirely from the guide element 1, on the other side of the longitudinal axis 27, at an angle relative to the said wall which is chosen for deflected core drilling. The deflection channel 19 has a cross section adapted so that said corer 7 can pass therein guided by the bottom 23 and the sides 25.

A longitudinal cavity 29 is cut in the guide element 1, parallel to the abovementioned longitudinal axis 27, and is arranged to allow passage from the internal space 5 above to the actuating means 15 of the expandable device 9. Preferably, this longitudinal cavity 29 and the guide element 1 are coaxial. In the internal space 5 of the guide element 1, possibly even in a rear portion 31 of the deflection channel 19, there is arranged an external tube 33 of the corer 7 above. 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 string of rods 17, and is releasably locked in the guide element 1, in particular of so that the crown 35 is included inside the imaginary outer envelope of the guide element 1. The outer tube 33 can be carried (FIGS. 4 and 5) by two bearing bushes 36 so as to be able to , after having been released, turn and slide in the internal space 5 and in the deflection channel 19 and then be able to progress in training.

In the outer tube 33 of the core barrel 7, to actuate the expandable device 9, there is temporarily disposed a removable tube 39 which extends from the interior of this outer tube 33, through the longitudinal cavity 29, to the means of 'selective actuation 15. The removable tubing 39 has a rear end 41 open to let the pressurized fluid pass therefrom from the drill string 17. A hooking piece 43 is fixed to this rear end 41 and is arranged for subsequent removal of the pipe 39 outside the above-mentioned assembly. A front end 45 of said tubing 39 is arranged for a releasable and sealed connection between the tubing 39 and the selective actuation means 15 in order to communicate to the latter, by said tubing 39, the aforementioned pressurized fluid. For example, the tubing 39 (FIG. 1) is pressed into a through hole 47 of the expandable device 9, two O-rings 49 sealing between the tubing 39 and said device 9.

In this same outer tube 33, after having expanded the expandable device 9 and having removed said tube 39 from the assembly, one can have either an ordinary inner tube 51 (FIGS. 8 to 10) for the core barrel 7 or a plug 53 of drilling (Figures 11 to 13) which completes the crown 35 to form a drilling head. At its anterior end which can project from the crown 35, the plug 53 is then fitted with knives or abrasive elements. The inner tube 51 and the plug 53 also each have a hooking piece 43 fixed each time at their rear end and arranged for their descent into, or subsequent withdrawal from, the above-mentioned assembly.

To fix them to each other, the guide element 1 can comprise (FIG. 1) a sliding member 55 and the expandable device 9 can comprise a chamber 57 in which the sliding member 55 is guided and can slide between of them stop positions, a position (shown) in which the sliding member 55 closes a passage 59 for output of the fluid contained under the pressure determined in the expandable device 9 expanded and a position (not shown) in which this sliding member 55 opens this outlet passage 59. The external tube 33 may have an external support face 61 (FIG.

3) turned upstream and intended to cooperate with an internal abutment face 63 (FIG. 4) which comprises the guide element 1, which is turned downstream and against which the bearing face 61 can abut when said outer tube 33 is pulled out of the borehole. In addition, the outer tube 33 can be advantageously retained fixed, releasably, in the guide element 1 by a pin 65 (Figure 3) calibrated to break during a controlled movement of rotation and / or translation of the outer tube 33 in the guide element 1 fixed to the wall of the borehole by the expandable device 9 expanded. To be used, the deflected core / drill assembly which has just been described is first assembled, equipped with the removable tubing 39 according to FIGS. 1 to 5, and is fixed to a drill string 17 by means of of the outer tube 33. The assembly is then lowered into the borehole and rotated if necessary (see below), by acting on the drill string 17, so that the deflection channel 19 has its opening in the direction in which it is desired to core or drill in a deviated manner. The fluid sent from the surface, through the drill string 17 (Figure 5), passes through the outer tube 33 and, through an annular space between it and the rear end 41 of the tubing 39, this fluid arrives in the tube 39 through openings 67 which are formed therein. A sealing ring 69 of soft metal can be provided between the tubing 39 and the outer tube 33 and prevents said fluid from escaping from the path described. The fluid arrives (FIG. 1) at the front end 45 of the tubing 39 and, put at an adequate pressure, inflates the sleeve 18 so that the latter 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 called "wire line"("cablework") in the trade, 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 (FIGS. 7 to 10) can be lowered into position in the outer tube 33 by the same "wire line" technique. The inner tube 51 can be held in place, at a stop near or in the crown 35 by the pressure of the fluid sent in the assembly for coring purposes. To start the deviated coring, it is first necessary to break the releasable blocking, in particular by rotating the outer tube 33, using 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 spindle 65 calibrated for this purpose. The controlled corer 7, driven in rotation and pushed through the drill string 17, is guided by the guide element 1 to attack the wall of the borehole at the angle provided.

If it is desired to make a deviated drilling in the set direction, either before a deviated coring, or without consecutive coring, or even after a deviating coring in this direction, one installs in the external tube 33, instead of the internal tube 51, said plug 53 (FIGS. 11 to 13) using the same "wire line" technique. Said stopper 53 can comprise (FIG. 11), in a bar 73 which composes it, a lock 75 which is pushed into abutment by a spring 77 in a projecting position outside 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 front and rear ends an inclined face arranged so that, when the plug 53 is inserted into the outer tube 33 or removed therefrom, 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 be able to receive the latch 75, which engages therein 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 lock 75 is in alignment with the groove 79. Otherwise, when the lock 75 and groove 79 are not aligned while the plug 53 is in place in the crown 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 engagement with the material to be drilled. The cooperation of the latch 75 and the groove 79 causes the drilling plug 53 to be coordinated in rotation by the outer tube 33 which likewise drives the crown 35.

One can notice (Figure 11) at the level where the latch 75 is located, one or more longitudinal conduits 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 from being able to hang thereon.

In the embodiment shown, the plug 53 is pushed longitudinally in abutment downstream, for example against an internal annular face 81 (FIG. 13) of the outer tube 33, by the pressure of the drilling fluid which passes there.

Note in Figures 13 to 11 that the bar 73 may be hollow between the attachment piece 43 and the housing of the latch 75 and have inlet and outlet ports so that fluid can flow there from upstream to the 'downstream. Another tubular section can be provided in said bar 73 between the latch housing 75 and the anterior end of the plug 53. Passages 82 (FIG. 11) can be dug in the anterior end of the plug 53 to bring about front nozzles 83 of the latter fluid from the annular space provided between the drill plug 53 and the outer tube 33.

In one embodiment of the invention, the tube 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 mounted in leaktight manner to slide in said tube 39 between a starting position (represented in FIGS. 3 and 14) upstream from the orifice (s) 87, in order to allow fluid entering them through the tube 39, and another position (not shown) abutting downstream, in which the same piston 89 closes the orifice or orifices 87, the fluid then being channeled 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 in the assembly or to be thrown through the drill string 17, and it is intended to close at least a large section of the passage for the fluid in the removable tube 39 in the upstream to downstream direction, and to release this passage in the opposite direction. To ensure a desired reduced passage from upstream to downstream, it can be shaped, 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 bypass valve seat 95 and valve 97.

When the assembly described above, comprising said removable tube 39, is lowered into the probe hole, the fluid contained in this hole must be able to escape towards the surface without causing a force capable of dislodging the tube 39 from its overall mounting position. When the holes 87 are open as shown, fluid can enter through them into the tubing 39 and rise to the surface without unduly pushing the tubing 39 towards the surface. When the assembly is placed in the deviated drilling / coring position, it suffices to give a pressure stroke of predictable value at a desired time so that the annular piston 89 is pushed from its starting position shown to its stop position. downstream, in which it closes the orifices 87 in order to force the fluid to go to the selective actuation means 15 to inflate the sleeve 18.

The passage through the annular piston 89 having to be relatively large to allow the downstream fluid to pass efficiently upstream as explained above, the aforesaid pressure stroke intended to move this piston 89 may have to be exaggeratedly large, an undesirable level. To safely obtain a displacement of the annular piston 89 at a reasonable pressure, the above-mentioned valve or ball 95 is used. It then closes said passage from upstream to downstream and provides the fluid with a larger surface, so that the annular piston 89 is pushed efficiently, by the combination with the ball 95, in its position for closing the orifices 87 The bypass (s) 98 allow fluid to pass from upstream to downstream to activate 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 embodiments described and that many modifications can be made to these 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 on the tubing 39, a positioning stop 99 (Figure 5), in particular combined with the ring 69 , which can bear against an adequate surface provided in the outer tube 33. It is also possible to adapt a releasable lock 100, in particular to two bolts 101, which is mounted on the pipe 39, including the two bolts 101, shaped accordingly, are automatically blocked by the action of a spring 103 in longitudinal notches 105 or other receptacles cut in the outer tube 33. During a given pull on said attachment piece 43 to remove the tubing 39 from 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 can be arranged a guide nose 107 whose front 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 inserted, for example, in said guide nose 107 or between the latter and the rest of the coring assembly or deviated drilling. This measurement system can be of the type which records data, then accessible after having brought said assembly and the system to the surface, or of the type which transmits orientation data in real time to an operator on the surface. Depending on the coring equipment used, the operator can possibly use this data transmitted in real time, so as to act on the assembly and give it a specific orientation for drilling and / or coring.

In another embodiment, said orientation measurement system can be associated with the removable tubing 39, preferably at its posterior end 41. This system can be fixed there and then it is not reassembled until after the inflation of the elastic sleeve 18 and either it has transmitted in real time data on the orientation of the guide element 1, or this data is taken from the system once brought to the surface. Based on these orientation data of the assembly as it was positioned in the borehole, it is possible to deduce therefrom a deviation from a desired orientation and modify the orientation accordingly by acting on the undercarriage. rods.

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

In either case, after having equipped said assembly with the aforementioned system, and before lowering everything into the borehole, it is possible to calibrate said system in order to know unequivocally its orientation relative to that of the channel. deflection 19 for example and to be able to safely adjust the orientation of this channel.

We could also prefer, for the inflation operation, a particular fluid, without solid particles, to ensure flawless operation of the check valve. This particular fluid could be sent under pressure through the drill string 17 or be stored in the above-mentioned assembly and put under pressure at using a coring / drilling fluid acting in particular on a piston 20 for separating the two fluids.

A coring or drilling assembly allowing this operation is illustrated in FIGS. 15 to 23. In FIGS. 15 to 18, the assembly according to the invention is on 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, this 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 part 113 and a second part 114 capable to perform a reciprocal sliding movement.

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

In the position illustrated in FIG. 18, the fluid supplied 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 therefore driven upwards as soon as the product of this pressure by the first surface of the piston overcomes the resistance of the friction of the seals between the piston 20 and the external 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 thereby allowing a purge of the lower compartment of the chamber 117.

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

In FIGS. 19 to 22, the assembly according to the invention has been lowered into the borehole and the expandable device 9 is in the process of expansion. Tap 109 was closed.

As can be seen from FIG. 22, the removable tubing 39, as described in the embodiment illustrated in FIGS. 1 to 14, is pressed in leaktight manner in one end of a tubular throttling element 121. A at its end, this throttling element 121 is provided with a throttle 122 which places the cavity of the throttling element in communication with the probe hole by an outlet conduit 123 and which causes an increase in pressure upstream.

Upstream of the choke, in the direction of flow of the drilling fluid type supplied by the removable tubing 39, the throttle element 121 is provided with small orifices 124 which are directed radially outwards and allow thus a part of the drilling or coring fluid to reach the compartment of the chamber 117 which is located opposite to that receiving the expansion fluid.

The throttle element 121 therefore separates the drilling fluid under pressure into two streams, a main stream at high flow rate which is discharged into the borehole and a secondary stream at low flow rate which serves to act on the separation piston 20 When the product of the pressure of the drilling fluid by the surface of the separation piston 20 is greater than the sum of the product of the pressure of the expansion fluid by the surface of the separation piston 20 and the friction of the separation piston 20 on the inner wall 118 of the chamber 117, the piston is moved downwards.

In the low position, the piston 20 comes to bear against the stop 125.

In the low position of the drilling or coring assembly according to the invention, the second part 114 of the check valve 22 has been immobilized in the borehole by known means. The first part 113 is then lowered by sliding 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.

Also in this position, the radial holes 132 provided in the second part 114 of the check valve 22 are received opposite the holes radials 133 of a support tube 134 of the first part 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 part 114 relative to to the rest of the drilling and coring assembly and therefore also with respect to the first part 113.

As 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 downward the ball 127 of the non-return valve integrated in the check valve 22, at against the return spring 129. A passage of expansion fluid is then allowed from the chamber 117 of the separation piston 20 towards the cylindrical cavity 112, where the pressure increases correspondingly. At a moment, the pressure exceeds the determined pressure making it possible to overcome the resistance of the expandable device 9. As shown in FIG. 20, the expandable device is then expanded, which allows the assembly according to the invention to be immobilized at 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 exterior of the fluid located in the upper compartment of this chamber (see FIG. 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 meanwhile maintained in its expanded position, with no possibility of the 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 detached and reassembled (see fig. 26).

A traction is also exerted upwards on the support tube 134 of the first part 113 of the check valve 22. This traction is sufficient to shear the screws 135, as shown in FIG. 25. The second part 14 of the valve 22 is then released and can slide in its low position, which again frees a passage 116 from the cylindrical cavity 112 towards the cylindrical chamber 117 (as described with reference to FIG. 17). The product of the pressure of the expansion fluid by 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 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 to its initial position in application on the support cylinder 111, which allows the desired displacement of the drilling or coring assembly.

The latter drilling or coring assembly according to the invention, as illustrated in FIGS. 15 to 26, has the advantage of using a clean fluid at the check valve and the expandable device. ie without suspended particles which are a source of fouling of the check valve. Furthermore, the division of the current of drilling fluid under pressure into main current and secondary current of low flow makes it possible to act in a controlled manner on the separation piston, and therefore on the expandable device, without taking account of the flow of drilling. Separate pumping of drilling fluid during the expansion process is not necessary; the pumping facilities required for drilling or coring can be used.

Legend of figures

S direction of advance of coring / drilling

I guide element 3 rear end of 1

5 internal space of 1

7 corer

9 expandable device

I I anterior end of 1 13 external lateral surface of 9

15 means of selective actuation of 9

17 drill string

18 sleeve of 9

19 deflection channel in 1 20 separation piston

21 posterior end of 19

22 check valve

23 background of 19

25 lateral sides of 19 27 longitudinal axis of 1

29 longitudinal cavity in 1

31 posterior portion of 19

33 outer tube of 7

35 core bit of 7 36 bearing bushes

39 removable tubing

41 posterior end of 39

43 hanging piece of 39, 51, 53,

45 front end of 39 47 through hole 9

49 O-rings of 9

51 inner tube of 7

53 drill plug for 35

55 sliding member 57 room for 55 fluid outlet passage of 9 external face of support of 33 internal face of abutment of 1 calibrated spindle, between 33 and 1 openings in 39 sealing ring between 33 and 39 bar of 53 lock of 53 spring of 73 longitudinal groove in 33 longitudinal duct or ducts in 33 internal annular support face of 33 passages in 53 front nozzles of 53 orifice (s) in 39 annular piston in 39 breakable element valve seat in 39 valve / ball bypass of 95 positioning stop of 39 releasable lock of 39 bolts of 100 spring of 100 longitudinal notches in 33 for 100 guide nose supply pipe tap annular cavity in 111 support cylinder of 9 cylindrical cavity first part of 22 second part of 22 support seat for 113 passage annular 117 cylindrical chamber receiving 20

118 outer wall of chamber 117

119 stop

120 non-return valve

5,121 throttling element

122 choke

123 outlet duct

124 radial holes in 121

125 stop

10,126 support seat for 113

127 ball of 128

128 non-return valve

129 return spring of 127

130 safety valve

15,131 radial outlet ducts of 110

132 radial holes of 114

133 radial holes of 134

134 support tube of 113

135 shear screws

Claims

REVEND1CAT1ONS

1. An assembly intended for coring or deviated drilling, in a wall of a borehole drilled or cored beforehand in a formation, the assembly comprising: - a guide element (1) of an external diameter chosen to be able to enter in the borehole to a desired depth for the deflected 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, an internal space (5) coaxial with a diameter suitable for housing a core barrel (7), an expandable device (9) fixed to the front end (11) of the guide element (1), - having a surface lateral lateral (13) which, in a state of rest, has a cross section smaller than that of the borehole and which is arranged to take, in an expanded state of the device (9), an immobilizing support against the wall of the borehole, and comprising selective actuation means (15) age ncés to receive a pressurized fluid which causes expansion of the expandable device (9) beyond a predetermined pressure, and a valve arranged to automatically oppose an outlet of this fluid at a determined pressure from said actuating means (15 ), a deflection channel (19) hollowed out in the guide element (1) in extension of the internal space (5), upstream of the expandable device (9) in said direction of advance (S), the channel deflection (19) having - a rear end (21) coaxial with said internal space (5), a bottom (23) and lateral sides (25) which follow, from this rear end (21) of the channel (19) and in the direction of the expandable device (9), a direction inclined relative to the longitudinal axis (27) of the guide element (1), the bottom (23) intersecting this axis (27), the channel (19) extending to fully open the guide element (1), on the other side of the longitudinal axis (27) , at an angle, with respect to the above-mentioned wall, chosen for the deflected coring, and a cross section adapted so that said corer (7) can pass therein guided by the bottom (23) and the sides (25), a longitudinal cavity (29) cut in the guide element (1) parallel to the longitudinal axis (27) above, and arranged to allow passage from the internal space (5) above to the actuating means ( 15) of the expandable device (9), - in the internal space (5) of the guide element (1), possibly even in a rear portion (31) of the deflection channel (19), an external tube (33 ) of the aforementioned corer (7) comprising a coring ring (35) fixed to the front end of this outer tube (33), - to be suspended from a string of rods (17), and releasably blocked in the guide element (1), in particular so that the crown (35) is included inside an imaginary outer envelope of the guide element (1), arranged to be able to slide, after being released , in the internal space (5) and in the deflection channel (19) and then progress in the formation, in the tube outside (33) of the core barrel (7), temporarily arranged to actuate the expandable device (9), a removable tube (39) which extends from the inside of this outside tube (33), through the longitudinal cavity (29 ), up to the selective actuation means (15), and which has a rear end (41) open to allow the passage of pressurized fluid from the drill string (17), a fastening piece (43) fixed at this rear end (41) and arranged for a subsequent withdrawal of the tubing (39) from the aforementioned assembly, a front end (45) arranged for a releasable and sealed connection between the tubing (39) and the means of selective actuation (15) in order to communicate to the latter, via said tube (39), the fluid under pressure, and - in this same outer tube (33), after having expanded the expandable device (9) and having removed said tubing (39) outside the assembly, i.e. an inner tube (51) of corer is a crown plug (53) arranged so that it can make drilling, the inner tube (51) or the plug (53) having a hooking piece (43) fixed at its rear end and arranged for its descent and its subsequent removal from the above-mentioned assembly.

2. Coring or drilling assembly according to claim 1, characterized in that, for their mutual fixing, the guide element (1) comprises a sliding member (55) and the expandable 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 an outlet passage (59) for the fluid contained under the pressure determined in the expandable device (9) expanded and a position in which this member (55) opens this outlet passage (59).

3. Coring or drilling assembly according to either of claims 1 and 2, characterized in that the outer tube (33) of the corer (7) has an external bearing face (61) facing the upstream and intended to cooperate with an internal abutment face (63) which comprises the guide element (1), which faces downstream and against which abuts the bearing face (61) when said outer tube ( 33) is pulled out of the borehole.

4. Coring or drilling assembly according to any one of claims 1 to 3, characterized in that the outer tube (33) of the corer (7) is retained releasably fixed in the guide element (1) by a spindle (65) calibrated to break, during a controlled movement of rotation and / or translation of the outer tube (33) in the guide element (1) fixed to the wall of the probe hole by the expandable device ( 9) dilated.

5. Coring or drilling assembly according to any one of claims 1 to 4, characterized in that the tube (39) has an orifice (87), or several orifices (87) at the same level, through its wall, an annular piston (89), with an interior passage for the fluid, is mounted in leaktight manner to slide in the tube (39) between a starting position upstream of the orifice (s) (87), in order to allow fluid to 'Enter the tubing (39), and another stop position in which it closes the orifice (s) (87), the fluid being channeled through the annular piston (89).

6. Coring or drilling assembly according to claim 5, characterized in that the annular piston (89) is held in said starting position by a breakable element (91) calibrated to break under a push of the piston (89) subjected to a pressure above a given threshold.

7. Coring or drilling assembly according to either of claims 5 and 6, characterized in that the tube (39) comprises - associated with 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 at least one large passage for the fluid in the pipe (39) in the upstream to downstream direction, and to release this passage in the opposite direction, - at least one bypass (98), of reduced cross section compared to that of said passage, arranged in bypass of the seat valve (95) and valve (97).

8. Coring or drilling assembly according to any one of claims 1 to 7, characterized in that it comprises, to prevent longitudinal movement of the tubing (39) in said outer tube (33) - downstream, a positioning stop (99) and

- upstream, a releasable lock (100) which is mounted on the tube (39), which automatically locks in the outer tube (33) and which is connected to the attachment piece (43) of the tube ( 39) so that it becomes free during a given pull on said attachment piece (43).

9. Coring or drilling assembly according to any one of claims 1 to 8, characterized in that in front of the expandable device (9) 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, characterized in that it comprises a system for measuring the orientation in the ground of an object equipped with this system, which can be of the type which records orientation data which can be analyzed after bringing the system to the surface and / or of the type which transmits these data to the surface in real time during operation in the borehole.

11. Coring or drilling assembly according to claim 10, characterized in that said measuring system can be disposed in the guide nose (107) or between the latter and the rest of the deflected coring or drilling assembly.

12. Coring or drilling assembly according to claim 10, characterized in that said measuring system can be associated with the removable tubing (39), preferably at the rear end (41) of this tubing (39).

13. Coring or drilling assembly according to any one of claims 1 to 12, characterized in that the actuating means (15) are arranged to receive, as pressurized fluid, a fluid of the drilling or coring fluid type .

14. Coring or drilling assembly according to any one of claims 1 to 12, characterized in that the actuating means (15) are arranged to receive, as pressurized fluid, an expansion fluid pressurized by a fluid of drilling or coring fluid type by means of a separation piston (20).

15. Coring or drilling assembly according to claim 14, characterized in that it comprises a throttling element (121) into which the removable tubing (39) opens and which puts the fluid of the drilling or coring fluid type under pressure and divides it into a main current passing through the throttling element (121) towards the inside of the borehole and into a secondary current, of lower flow than the main current, which serves as pressurized fluid capable of pressurizing the expansion fluid.

16. Coring or drilling assembly according to claim 15, characterized in that the separation piston (20) slides in a sliding chamber (117) of the above actuation means between two extreme positions and has a first surface which enters in 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 two extreme positions mentioned above when the product of the pressure of the expansion fluid by the second aforesaid surface is greater than the sum of the product of the pressure of the fluid of the drilling or coring fluid type by the first aforesaid surface and the friction between the separation piston and the chamber sliding (117), in that the separation piston slides in a second direction towards the other of the two extreme positions mentioned above when the product of the pre ssion of the drilling or coring fluid type by the aforesaid first surface is greater than the sum of the product of the pressure of the expansion fluid by the aforesaid second surface and of 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 reach said determined pressure beyond which an expansion of the expandable device (9) takes place, while, during sliding the separation piston (20) in the second direction, the expansion fluid reaches said determined pressure and causes expansion of the expandable device (9).