VERTICAL DRILLING SYSTEM OF THE SCREW TYPE WITH TRAJECTORY CORRECTION DEVICE

Description

Arrière-plan de l'invention

[0001] The present invention relates to the field of manufacturing deep foundations in soil, and in particular to the field of column support, such as piles. It also relates to the construction of foundation piles at ground level, the fabrication of watertight barriers using secant piles, and more generally the construction of any type of wall using secant or contiguous piles, regardless of the function of said wall.

[0002] Column or pile support refers to all types of support in which piles are installed in the ground: Parisian wall, Berlin wall, secant pile wall, contiguous pile wall, etc.

[0003] Piles are generally made of concrete or grout. They can also be obtained by a technique of mixing soil and a binder, generally called "soil-mixing".

[0004] Piles can be reinforced, for example through the use of a reinforcement cage, a tube or a metal profile.

[0005] To construct such piles, a drilling rig known as a continuous auger is commonly used. This rig consists of a hollow core containing a drilling tool made of a helical blade. With this type of drilling rig, the well is drilled in a single pass of the auger to the required depth. To construct the pile core, grout or concrete is injected from the lower end of the auger as it ascends.

[0006] For retaining structures, it is important to guarantee the position of the piles regardless of their depth in order to guarantee the geometry of the spaces created underground.

[0007] Similarly, for foundation piles whose upper level is located at a certain depth of the working platform, the actual position of the pile at that depth must be guaranteed.

[0008] However, when drilling using a continuous auger, the drilling trajectory is often poorly controlled, resulting in sometimes significant deviations from the theoretical drilling trajectory, which is generally vertical.

[0009] Deviation generally refers to the distance between the actual position of the auger and its theoretical position at a given depth. It is usually defined as the distance between the actual and theoretical positions divided by the depth and expressed as a percentage, with the distance typically considered in a horizontal plane.

[0010] Some continuous augers exhibit deviations of up to 5%, whereas deviation tolerances for retaining structures are generally less than 0.5%. Objet et résumé de l'invention

[0011] One aim of the present invention is to provide a well drilling system in soil that reduces the risk of deviation from the theoretical trajectory.

[0012] To this end, the invention relates to a system for drilling a well in soil along a theoretically vertical drilling trajectory, characterized in that it comprises: a drilling device comprising a hollow core having a longitudinal axis, the hollow core being equipped with a drilling tool; a first rotation device for rotating the hollow core and the drilling tool around the longitudinal axis; a connecting element extending inside the hollow core; the connecting element comprising a dip tube having a lower part equipped with at least one injection hole, the dip tube being connected to a fluid supply source; a pilot device disposed at the lower end of the connecting element and having a face inclined with respect to an axis of the pilot device;the pilot device having: an active state in which the pilot device is oriented and maintained relative to the ground in a correction angular position, so as to correct the movement trajectory of the drilling device according to a trajectory correction direction considered in a horizontal plane, the trajectory correction direction being the direction corresponding to the intersection between the inclined face and a vertical plane orthogonal to the inclined face, and a passive state in which the pilot device does not modify the movement trajectory of the drilling device; a hollow core deviation measurement device to identify any deviation between the movement trajectory of the drilling device and the theoretical drilling trajectory and to determine a deviation direction of the drilling device relative to the theoretical drilling trajectory, said deviation direction being considered in the horizontal plane;a control device configured to, when a deviation is measured, bring the pilot device into its active state at a predetermined angular correction position such that, viewed in the horizontal plane, the trajectory correction direction associated with the angular correction position is opposite to the direction of deviation.

[0013] For the purposes of the invention, rotation means turning or pivoting the connecting element around the longitudinal axis over one or more turns, or even over a fraction of a turn, in one direction or the other.

[0014] By column, we mean any supporting element, and in particular a cast pile.

[0015] By substantially vertical, we mean a drilling direction whose deviation from the vertical is between 0° and 5°, preferably between 0° and 1°.

[0016] In the context of the invention, the theoretical drilling trajectory can be predetermined before the drilling operation, or determined during drilling with respect to the geometry or orientation of a neighboring column previously constructed in the ground in order to obtain two columns juxtaposed and intersecting along their common length.

[0017] It is understood that the pilot device, particularly in its passive state, can rotate relative to the hollow core, either in the same direction or in the opposite direction. Without departing from the scope of the present invention, in its passive state, the pilot device can also be prevented from rotating relative to the hollow core.

[0018] It is also understood that the pilot device, at least in its active state, extends axially outside the hollow core, beyond its lower end.

[0019] When a deviation in the drilling path from the theoretical borehole path is detected by the deviation measurement device, the pilot device is activated to correct the borehole path. To do this, the pilot device is oriented and held relative to the ground at the correction angle. This angle is determined so that the pilot device modifies the borehole path as the borehole advances, thereby reducing the deviation from the theoretical borehole path. "Maintaining the correction angle" means holding the borehole within ±10°, preferably 5°, of this angle.

[0020] Preferably, maintaining the pilot device relative to the ground is achieved by locking the pilot device in rotation relative to the ground in the angular correction position.

[0021] The modification of the trajectory of movement of the hollow core is obtained by the fact that the pilot device, when moving in the ground in its active state, tends to move in a direction inclined relative to the longitudinal axis of the hollow core, which has the effect of making it rotate in a vertical plane.

[0022] According to an advantageous embodiment, the drilling system further comprises a second rotation device, connected to the connecting element, for rotating the connecting element and the pilot device around the longitudinal axis, the connecting element is able to rotate relative to the hollow core, and the control device is configured to actuate the second rotation device when a deviation is measured in order to bring the pilot device into its active state in said angular correction position.

[0023] In this embodiment, the orientation of the pilot device to its angular correction position is achieved by the second rotation device, which rotates the connecting element relative to the ground. The rotational locking of the pilot device relative to the ground is preferably achieved by the second rotation device.

[0024] Once the trajectory has been corrected, the pilot device is returned to its passive state.

[0025] By "opposite to the direction of deviation", we mean that the direction of trajectory correction is directed in a direction opposite to the direction of deviation, without the direction of correction necessarily being parallel to the direction of deviation.

[0026] Advantageously, the control device also includes a calculation device to calculate the angular position of correction from the direction of deviation determined by the measuring device.

[0027] Preferably, said horizontal plane in which the direction of deviation extends has a frame of reference equipped with at least one axis, and the angular position of the pilot device is determined from an angle between said axis of the frame of reference and the direction of deviation.

[0028] According to a first embodiment, the pilot device is configured to rotate in the same direction and at the same speed as the hollow core, when said pilot device is in the passive state.

[0029] To achieve this, the drilling device preferably includes a coupling device to block the rotation of the pilot device relative to the hollow core when said pilot device is in the passive state.

[0030] This coupling device includes, for example, a dog clutch link.

[0031] According to a second embodiment, the second rotation device is configured to rotate the pilot device in the opposite direction to the rotation of the hollow core, when said pilot device is in the passive state.

[0032] Rotating the hollow core and pilot device in opposite directions prevents the drilling device's movement trajectory from changing.

[0033] According to another embodiment, the pilot device is also translationally mobile relative to the hollow core, the drilling system further comprising a displacement device for translationally moving the pilot device relative to the hollow core along the longitudinal axis, so that the pilot device has a deployed position and a retracted position.

[0034] In this alternative embodiment, the drilling system may or may not include the aforementioned second rotation device. In the variant where the second rotation device is absent, disengageable dog-type coupling means can be provided to rotationally couple the hollow core and the pilot device. In this case, the pilot device is brought into the correction angular position by actuating the first rotation device, the pilot device then being rotationally coupled to the hollow core. To correct the trajectory, the pilot device is brought into the deployed position after disengaging the coupling means, and then the hollow core is advanced by rotating it using the first rotation device until the pilot device is brought into the retracted position.In this case, the pilot device is maintained in its angular correction position, during deployment, by the displacement device.

[0035] When the second rotation device is present, the pilot device is blocked from rotating - during the deployment of the pilot device - by means of the second rotation device.

[0036] Preferably, in its retracted position, the pilot device extends slightly beyond the lower end of the hollow core. Alternatively, the pilot device can be entirely housed within the hollow core.

[0037] Advantageously, the displacement device is configured to move the pilot device in translation relative to the hollow core by jacking, driving or vibratory driving.

[0038] Preferably, in its active state, the pilot device is in the deployed position, while in its passive state, the pilot device is in the retracted position.

[0039] According to the invention, the connecting element comprises a dip tube which has a lower part provided with at least one injection hole, the dip tube being connected to a fluid supply source.

[0040] Such a dip tube is described in particular in FR 2 566 813 and FR 2 831 205. It allows fluid to be injected into the well during the ascent of the drilling rig, in order to create the column.

[0041] Preferably, the injection hole is located above the lower end of the hollow core when the pilot device is in the deployed position. This injection hole is therefore also located above the lower end of the hollow core when the pilot device is in the retracted position. The pilot device also includes an injection position in which the injection hole is located below the lower end of the hollow core.

[0042] The dip tube is preferably brought into the injection position by means of the displacement device which moves the pilot device downwards in translation in order to uncover the injection hole.

[0043] Advantageously, the measuring device includes a deviation sensor located in the lower part of the hollow core.

[0044] The deviation sensor allows the measurement of a deviation distance, considered in a horizontal plane, between the actual position of the lower end of the hollow core and the theoretical drilling trajectory, generally vertical.

[0045] Advantageously, the drilling system further includes a depth-measuring device for the drilling rig. The measuring device is configured to measure the angle of deflection of the hollow core relative to a vertical direction, and the control device is configured to bring the pilot device into its active state—for example, by activating the second rotation device—when the ratio of the deflection distance to the depth reached by the drilling rig is greater than or equal to a predetermined threshold, this threshold being potentially depth-dependent.

[0046] Furthermore, without departing from the scope of the present invention, the control device may be configured to operate only from a certain depth, for example 3 m.

[0047] For example, if the well has a desired depth of 20 m, the control device can be configured to activate at a depth of 3 m if a deviation greater than 2 cm is detected. Then, at a drilling depth of 15 m, the control device can be configured to activate if a deviation greater than 3 cm is detected.

[0048] Thus, the deviation correction of the drilling device is carried out automatically and continuously during the drilling operation.

[0049] Advantageously, drilling is carried out continuously, with alternating periods during which the drilling device moves along a trajectory deemed satisfactory, and periods during which the pilot device is locked in rotation in a defined angular position when the trajectory needs to be corrected because the deviation is greater than a predetermined threshold.

[0050] Advantageously, the drilling device is an auger, for example an auger as described in FR 2 566 813 or FR 2 831 205, or any other type of continuous auger.

[0051] According to the present invention, the pilot device comprises a panel inclined with respect to a vertical plane, and the trajectory correction direction is the direction corresponding to the intersection between the inclined panel and a vertical plane orthogonal to the inclined panel.

[0052] The inclined face therefore acts as a kind of forward rudder, in order to modify the trajectory of movement of the hollow core during the penetration of the drilling device into the ground.

[0053] The invention also relates to a method for drilling a well in soil along a theoretical drilling trajectory, characterized in that: a drilling system is provided according to any one of the preceding claims; the drilling device is introduced into the ground while rotating the hollow core, the pilot device being in its passive state; the deflection of the hollow core is measured in order to determine a direction of deviation of the drilling device from the theoretical drilling trajectory; when a deviation greater than a predetermined threshold is measured, the pilot device is brought into its active state by orienting and holding it relative to the ground in a determined angular correction position such that, viewed in a horizontal plane, the trajectory correction direction associated with the angular correction position is opposite to the direction of deviation.

[0054] The introduction of the drilling device into the ground continues, and the pilot device, in its active state, has the effect of rotating the hollow core so as to make it return towards the theoretical drilling trajectory.

[0055] If the measured deviation falls below the predetermined threshold, the pilot device is returned to its passive state.

[0056] Advantageously, when a deviation is measured: The pilot device is brought into its active state by orienting and maintaining the pilot device relative to the ground in a determined angular correction position such that, considered in a horizontal plane, the trajectory correction direction associated with the angular correction position is opposite to the deviation direction; the pilot device is brought into its deployed position; the hollow core is moved relative to the ground so that the displacement of the hollow core follows the displacement of the pilot device.

[0057] The translational movement of the pilot device in the ground alters the inclination of the connecting element and the hollow core. When the hollow core catches up with the pilot device, which is then in a retracted position, the movement trajectory of the hollow core is corrected.

[0058] Again, when the measured deviation is less than the predetermined threshold, the pilot device is returned to its passive state and retracted position. Brève description des dessins

[0059] The invention will be better understood upon reading the following description of embodiments of the invention given by way of non-limiting examples, with reference to the accompanying drawings, in which: there figure 1 is an overview of a drilling system according to the present invention; the figure 2 is a detailed view of the upper part of the drilling system of the figure 1 ; there figure 3 is a detailed view showing the lower part of the drilling device and the pilot device according to a first embodiment of the invention; the figure 4A is a detailed view showing the lower part of the drilling device and the pilot device according to a second embodiment of the invention, the pilot device being in a retracted position; the figure 4B is a detailed view of the drilling rig of the figure 4A , the pilot device being in the deployed position; the figure 4C illustrates the dip tube in the injection position; the figure 5A illustrates the drilling system according to a first embodiment of the invention, during drilling, with the trajectory not being deviated; the figure 5B is a projection onto the horizontal plane XY from the lower end of the drilling device figure 5A ; there figure 6A illustrates the drilling system of the figure 5A , the drilling rig having deviated from the theoretical vertical trajectory, the pilot device being in its active state in order to correct the deviation; the figure 6B is a projection onto the horizontal plane XY from the lower end of the drilling device figure 6A ; there figure 7A illustrates the drilling system of the figure 6A after trajectory correction; the figure 7B is a projection onto the horizontal plane XY from the lower end of the drilling device figure 7A ; there figure 8 illustrates a projection in the horizontal plane XY of the lower end of the drilling device when the latter has undergone a deviation along the axes X And Y ; THE figures 9 à 12 illustrate a drilling process implemented by the drilling system according to the second embodiment, illustrating trajectory correction after deviation detection; the figure 13 is a perspective view of a pilot device of the drilling system according to the invention; the figure 14 is a side view of the pilot device of the figure 13 ; there figure 15 is a diagram illustrating the actual trajectory of the drilling system of the figure 1 during a drilling operation; and the figure 16 is a variant of the drilling system of the figure 2 lacking a second rotation mechanism. Description détaillée de l'invention

[0060] By referring first to figures 1 And 2 , We will describe a drilling system 10 wells 9 in soil S, in accordance with the present invention, for the manufacture of columns, such as cast piles.

[0061] The drilling system includes a platform 20 on which a guide mast is mounted 22 which is essentially vertical in its operating position. A trolley is mounted on this mast, moving vertically. 24 which can be moved via cables 26 associated with an unshown motor. The trolley 24carries a first rotation device 28 including a drill head 29 enabling the rotation of a drilling device 30 containing a hollow core 32 equipped with a drilling tool 33, in this case a helical blade extending substantially along the entire length of the hollow core 32. In this example, the drilling device 30 It is therefore a vertical auger with a hollow core.

[0062] We observe that the soul is hollow 32 extends along a longitudinal axis L which is roughly vertical.

[0063] Inside the hollow soul 32 of the drilling device 30 a free-mounting connecting element 36 which is capable of rotating relative to the hollow core around the longitudinal axis L.

[0064] In this example, the linking element 36has the shape of a hollow tube whose lower end is equipped with a pilot device 40, which will be described in more detail below.

[0065] A movable plate 42 is connected to the drill head 29 via vertical jacks 44. This plate 42, as illustrated in figure 2 , receives the upper end 36a of the connecting element 36. In this embodiment, the drilling system further comprises a second rotation device 50, which is connected to the linking element 36, to rotate the connecting element 36 and the pilot device 40 around the longitudinal axis L.

[0066] In this example, the connecting element is a dip tube whose upper end is connected to a flexible hose 52 supplying the tube with concrete or grout.

[0067] As shown by figure 2 , the first rotation device 28 includes an engine 51 of rotating the hollow core 32. In addition, a rotary joint 60 ensures the connection through the plate 42 between the upper end of the connecting element 36 and smooth driving 52. We understand that the cylinders 44 allow the axial position of the connecting element to be modified 36 compared to the hollow soul 32. Furthermore, the cable 26 vertical displacement of the drill head 29 or its drive motor is associated with a linear displacement sensor 62 which allows the vertical displacement of the drilling rig to be measured. This displacement sensor constitutes a depth measurement device. H reached by the drilling device.

[0068] There figure 3 illustrates the lower end 30b of the drilling system 30 according to a first embodiment of the invention.

[0069] In the current phase of well drilling 9, the connecting element 36 and the hollow soul 32 can be rotationally fixed, for example by a dog clutch system, so that the pilot device 40 and the drilling rig 30 rotate together in the same direction, without relative rotational movement between the connecting element 36 and the hollow soul 32. According to another variant, illustrated in figure 3 , the pilot device 40 can be rotated by the second rotation device 50, in a direction of rotation opposite to the direction of rotation of the hollow core 32. As will be explained in more detail below, the second rotation device 50is also capable of blocking the rotation of the connecting element 36 relative to the ground S.

[0070] On the figures 4A et 4B , A second embodiment of the drilling system according to the invention has been illustrated. This second embodiment differs from the first in that the drilling device 30' includes a coupling device 70, In this example, a dog clutch is used to block the rotation of the pilot device. 40' compared to the hollow soul 32'. It is also noted that the pilot device 40' is mobile in translation relative to the hollow core 32' along the longitudinal axis L. The drilling system 10', the jacks 44 and the plate 42 constitute a displacement device 43 to move the pilot device in translation 40' compared to the hollow soul 32' along the longitudinal axis L,so that the pilot device 40' presents a deployed position, illustrated in figure 4B , and a retracted position illustrated in figure 4A .

[0071] Also, when the cylinders 44 are in deployed position, the pilot device 40' is in the retracted position, while when the cylinders 44 are in the retracted position, the pilot device 40' is in deployed position.

[0072] The mobility device 43 is also configured to move the pilot device 40' compared to the pilot device 32' by jacking, hammering or vibratory driving.

[0073] To do this, the displacement device 43 could also be equipped with a vibrating head not shown here.

[0074] In this example, the connecting element comprises a dip tube, which is equipped with injection holes at its lower end. 65 which are masked by the hollow soul 32' when the pilot device 40' is in the retracted position. Preferably, the injection holes 65 are also masked by the hollow core when the pilot device is in the deployed position. In this case, the pilot device can also be in an injection or concreting position, illustrated in figure 4C , in which the pilot device is further deployed so that the injection holes are exposed to allow concreting. To do this, the pilot device is moved downwards using the displacement device. 43, so that the injection hole 65 is located below the lower end 32'b of the hollow soul 32'.In this position, concrete is injected into the borehole, for example during the raising of the drilling rig. 30.

[0075] For a more precise explanation of the purpose of injection holes 65, Reference can be made to document FR 2 831 205 which describes in detail the process of manufacturing a pile using a continuous auger.

[0076] On the figure 16 , We have illustrated a variant of the second embodiment, in which the drilling system lacks a second rotation device. In this case, the rotation of the pilot device is achieved by the first rotation device. 51 after the connecting element is rotationally coupled by the coupling device 70 with an empty soul.

[0077] In the present invention, the main focus is on controlling the drilling trajectory of the drilling device.

[0078] With the help of figures 13 et 14 , We will now describe the pilot device in more detail. 40' of the drilling system 10' according to the second embodiment of the present invention.

[0079] The pilot program 40' presents a cylindrical shape including a first end 40'a equipped with a portion for attaching to the connecting element 36, and a second end part 40'b, opposite to the first end part 40'a. The second end part 40'b includes a front face equipped with cutting teeth D which form bulges. The pilot device 40' also includes a section P which is inclined with respect to a plane passing through the axis A of the pilot device 40' The angle of inclination between the pan P and the axis A of the pilot device 40' is referenced α on the figure 14 . The pilot program 40' also includes squares C protruding parts that are part of the dog clutch system 70 described above. In this embodiment, the angle α preferably has a value between 15° and 25°.

[0080] The function of this specific form of the pilot device 40' will be explained below.

[0081] It is specified that the pilot device 40 according to the first embodiment, it has a shape similar to that of the pilot device 40' according to the second embodiment. It differs from it in particular by the fact that it lacks squares C.

[0082] Regardless of the embodiment considered, the drilling system includes a device 80 hollow core deviation measurement 32, 32'to identify any deviation between the drilling rig's movement path and the theoretical drilling path. In this example, the theoretical drilling path is a vertical path, while the drilling rig's movement path is the actual path of the drilling rig.

[0083] The device 80 The hollow core deflection measurement device also includes a deflection sensor. 82 which is located in the lower part of the hollow core.

[0084] The device 80 The deviation measurement system is also configured to determine a possible direction of deviation. DD of the drilling rig relative to the theoretical drilling trajectory, the direction of deviation being considered in a horizontal plane Q which is defined by the coordinate system XY.

[0085] Furthermore, in accordance with the invention, the pilot device40,40' presents an active state in which the pilot device 40, 40' is oriented and maintained relative to the ground, preferably being prevented from rotating relative to said ground S, in a corrective angular position so as to correct the direction of movement T of the drilling device 30, 30' according to a trajectory correction direction DCT considered in the horizontal plane Q. The angular orientation and rotational locking relative to the ground of the pilot device 40,40' are operated by the second rotation device 50.

[0086] As illustrated in figure 4B , the trajectory correction direction DCT corresponds to the intersection between the inclined plane P and a plan P' which is vertical and perpendicular to the panel P. As explained above, we are interested in the projection onto the horizontal plane Qof this trajectory correction direction.

[0087] By referring to the figure 4B , It is understood that the conformation of the pilot device 40' (as with the pilot device 40) has the effect that, in its active state, the pilot device 40' tends, when it is embedded in the ground S, to move in translation according to the trajectory correction DCT illustrated on the figure 4B , This has the effect of changing the orientation of the connecting element and the hollow core. It is also understood that, depending on the angular position of the correction, considered in a horizontal plane, it is possible to modify the direction of trajectory correction. DCT.

[0088] When said pilot device is in its passive state, it is configured to rotate in the same direction and at the same speed as the hollow core, as previously mentioned, so that it does not alter the travel path of the drilling device.

[0089] Alternatively, when the pilot device is in the passive state, the second rotation device is configured to rotate the pilot device. 40, 40' in the opposite direction to the rotation of the hollow core 32'.

[0090] Depending on which of these variants the pilot device 40, 40' During the operation of the drilling device, the movement trajectory of the hollow core is not changed, which is why the pilot device is said to be in its passive state.

[0091] The pilot program 40, 40'is brought into its active state by blocking its relative rotation with respect to the ground after being oriented, by the action of the second rotation device, into the angular position enabling the desired trajectory correction direction. During the continued insertion of the drilling device, the connecting element and the hollow core pivot in a vertical plane passing through the trajectory correction direction. DCT, which has the effect of bringing the longitudinal axis back L of the hollow soul 32, 32' according to the theoretical drilling trajectory V.

[0092] The drilling system 10, 10' It also includes a control device 100 which is configured to actuate the second rotation device 50 when a deviation is measured by the device 80, in order to bring the pilot device 40, 40'in its active state by locking it in rotation relative to the ground in a determined angular correction position such that, considered in the horizontal plane Q, the trajectory correction direction DCT associated with the angular position of correction is opposite to the direction of deviation.

[0093] In the variant of the second embodiment, illustrated in figure 16 , in which the second rotation device 50 is absent, the control device 100 is configured to bring the pilot device into its active state by activating the first rotation device after activating the coupling device 70.

[0094] The control device 100 It also includes a calculating device 102 to calculate the angular correction position from the direction of deviation DD determined by the measuring device. The angular position of the correction is determined so that the direction of trajectory correction DCT is opposite to the direction of deviation. The control device drives the second rotation device to bring the pilot device into the desired angular correction position.

[0095] The deviation sensor 82 is configured to measure a distance d of deviation of the hollow soul 32, 32' relative to a vertical direction. This distance is considered in a horizontal plane passing through the deflection sensor. Furthermore, the control device is configured to actuate the second rotation device when the ratio of the deflection distance d on the depth HThe depth reached by the drilling device is greater than or equal to a threshold which may depend on the depth reached. For example, this threshold may be 0.3%.

[0096] This will be explained in more detail using the figures 5A à 8 which describe a process for drilling a well in the ground S according to a theoretical drilling trajectory V, in this case vertical, using the drilling system according to the first embodiment of the invention.

[0097] On the figure 5A , The drilling device was illustrated. 30. During drilling, the longitudinal axis L of the hollow core being parallel to the theoretical drilling direction V, These are therefore both vertical. The pilot device 40 is in its passive state and the pilot device is set in rotation by the second rotation device 50 in the opposite direction to the rotation of the hollow core32.

[0098] The drilling device 10 is therefore introduced into the ground while simultaneously rotating the hollow core 32.

[0099] We measure the potential deviation of the hollow core 32 using the device 80 measuring the deflection of the hollow core in order to determine a direction of deflection DD of the drilling rig in relation to the theoretical drilling trajectory V.

[0100] In figure 5A , No deviation is detected. Also, considered in the horizontal plane Q, the pilot device 40 is located in the center of the coordinate system XY illustrated in figure 5B .

[0101] During drilling, as schematically illustrated in figure 6A , a deviation illustrated by a deviation distance d is measured. This deviation distance d, measured at the depthH, For example, 5m, being greater than a predetermined threshold, for example 2 cm, or 0.4%, the control device drives the second rotation device so as to bring the pilot device 40 in its active state by orienting it and then locking it in rotation relative to the ground S in a determined angular correction position such that, considered in the horizontal plane Q, the trajectory correction direction DCT associated with the angular position of correction, which is opposite to the direction of deviation DD. It is understood that the deviation illustrated in figure 6A is schematic and exaggerated to facilitate understanding of the invention.

[0102] Without departing from the scope of the present invention, other threshold values ​​may be chosen by a person skilled in the art depending on the desired drilling accuracy.

[0103] In the example of the figure 6B ,To facilitate understanding, the direction of the diversion DD as well as the trajectory correction direction DCT extend along the axis X. However, these two directions could be non-parallel.

[0104] Finally, on the figure 7A , The position of the hollow core was illustrated. 32 after it is aligned again with the theoretical drilling trajectory V. The pilot device is then returned to its passive state, for example by rotating it in the opposite direction to the rotation of the hollow core. 32. Drilling therefore continues until a deviation exceeding a predetermined threshold is measured again.

[0105] On the figure 8 , We illustrated a case where the direction of deviation extends along a direction not parallel to the axes X And Y.The operating principle is identical. The pilot device is activated by orienting and locking it relative to the ground, so that the trajectory correction direction is opposite to the detected deviation direction. The trajectory correction direction DCT is determined in such a way as to correct the verticality of the hollow core when the drilling device is driven into the ground.

[0106] On the figures 9 à 12 , We have illustrated a well drilling process according to a second implementation method, using the drilling system according to the second embodiment illustrated in figures 4A et 4B .

[0107] This second method of implementation differs from the first in that, when a deviation exceeding a predetermined threshold is measured, the pilot device is brought into operation. 40' in its active state and in its deployed position, illustrated in figure 11 ,for example by translation and vibratory driving. Then, the hollow core is moved relative to the ground so that its displacement follows the movement of the pilot device, thereby correcting the verticality of the hollow core's trajectory, as illustrated in figure 12 .

[0108] The well drilling processes according to the first and second modes of implementation can advantageously be used in the context of a column manufacturing process, such as a pile, a process in which a fluid is injected into the well at the time of the ascent of the drilling device in order to form the column in the ground.

[0109] Finally, on the figure 14 , The curves of drilling tool deviation as a function of drilling depth have been illustrated. The curve GX illustrates the deviation along the axis X while the curve GY illustrates the deviation along the axis Y, and the curve GT illustrates the total deviation of the drilling device.

[0110] It is understood that the pilot device remains in its passive state down to a depth of approximately 8 meters, after which it becomes active down to a depth of approximately 12 meters, where it returns to its passive state. Therefore, the maximum deviation distance is approximately 3 cm for a depth between 8 and 10 meters. In other words, during the drilling operation, the deviation, expressed as a percentage, is at most 0.375%, and thus less than the critical limit of 0.5%.

Claims

1. A system (10) for drilling a well in a soil (S) along a substantially vertical theoretical drilling trajectory, comprising: a drilling device (30) including a hollow core (32, 32') having a longitudinal axis (L), the hollow core being provided with a drilling tool (33); a first device for setting in rotation (28) to set in rotation, around the longitudinal axis, the hollow core (32, 32') and the drilling tool (33); a linking element (36) extending inside the hollow core, the linking element including a tremie pipe which presents a lower part provided with at least one injecting hole (65), the tremie pipe being connected to a fluid supply source (52); characterized in that it comprises: a driving device (40,40') disposed at the lower end of the linking element and comprising a slanted section (P) with respect to an axis (X) of the driving device (40'); the driving device presenting: an active state in which the driving device is oriented and maintained with respect to the soil (S) in an angular correction position, in such a way as to correct the displacement trajectory (T) of the drilling device (30, 30') according to a trajectory correcting direction (DCT) considered in a horizontal plane, the trajectory correcting direction being the direction corresponding to the intersection between the slanted section and a vertical plane orthogonal to the slanted section, and a passive state in which the driving device does not modify the displacement trajectory of the drilling device; a hollow core (32,32') deviation measuring device (80) for identifying a possible deviation between the displacement trajectory of the drilling device and the substantially vertical theoretical drilling trajectory and determining a deviation direction (DD) of the drilling device with respect to the substantially vertical theoretical drilling trajectory (V), said deviation direction being considered in the horizontal plane (Q); a control device configured for, when a deviation is measured, bringing the driving device in its active state in an angular correction position determined in such a way that, considered in the horizontal plane (Q), the trajectory correcting direction (DCT) associated with the angular correction position is opposite to the deviation direction.

2. The drilling system according to claim 1, characterized in that the control device (100) further includes a computing device (102) for computing the angular correction position based on the deviation direction (DD) determined by the measuring device (80).

3. The drilling system according to claim 1 or 2, characterized in that the driving device (40, 40') is configured to rotate in the same direction and at the same speed as the hollow core (32, 32'), when said driving device is in the passive state.

4. The drilling system according to claim 3, characterized in that the drilling device (30') includes a coupling device (70) to lock the rotation of the driving device (40') with respect to the hollow core (32') when said driving device is in the passive state.

5. The drilling system according to any one of the preceding claims, characterized in that it further includes a second device for setting into rotation (50), connected to the linking element (36), to set in rotation the linking element and the driving device around the longitudinal axis (L), in that the linking element is capable of rotating with respect to the hollow core, and in that the control device is configured to actuate the second device for setting into rotation when a deviation is measured so as to bring the driving device in its active state into said angular correction position.

6. The drilling system according to claim 5, characterized in that the second device for setting into rotation is configured to make the driving device (40, 40') rotate in the opposite direction to the rotation direction of the hollow core, when said driving device is in the passive state.

7. The drilling system according to any one the preceding claims, characterized in that the driving device (40') is moveable in translation with respect to the hollow core (32'), in that the drilling system further includes a displacement device (43) for displacing in translation the driving device (40') with respect to the hollow core (32') according to the longitudinal axis (L), in such a way that the driving device (40') presents a deployed position and a retracted position.

8. The drilling system according to claim 7, the displacement device (43) is configured to displace the driving device (40') with respect to the hollow body (32') by jacking, jarring or vibratory driving.

9. The drilling system according to claim 7 or 8, characterized in that, in its active state, the driving device is in deployed position, whereas, in its passive state, the driving device is in retracted position.

10. The drilling system according to any one of claims 7 to 9, characterized in that the driving device further presents an injecting position, wherein the injecting hole (65) is located underneath the lower end of the hollow core.

11. The drilling system according to any one of the preceding claims, characterized in that the hollow core deviation measuring device (85) includes an inclination sensor (82) placed in the lower part of the hollow core.

12. The drilling system according to any one of the preceding claims, characterized in that it further includes a member for measuring the depth reached by the drilling device (30, 30'), in that the hollow core deviation measuring device is configured to measure a deviation distance (d) of the hollow body with respect to a vertical direction, and in that the control device is configured to bring the driving device in its active state when the ratio of the deviation distance (d) to the depth (H) reached by the drilling device is higher than or equal to a predetermined threshold.

13. The drilling system according to any one of the preceding claims, characterized in that the drilling device (30, 30') is an auger.

14. A method for drilling a well in a soil (S) according to a theoretical drilling trajectory (V), <b>characterized in that: a drilling system (40) is provided according to any one of the preceding claims; the drilling device is introduced in the soil (S) while setting the hollow core (32) into rotation, the driving device being in its passive state; the deviation of the hollow core is measured in order to determine a deviation direction of the drilling device with respect to the theoretical drilling trajectory; when a deviation higher than a predetermined threshold is measured, the driving device (40, 40') is brought in its active state by orienting it and maintaining it with respect to the soil (S) in an angular correction position, determined such that, considered in a horizontal plane (Q), the trajectory correcting direction (DCT) associated with the angular correction position is opposite to the deviation direction (DD).

15. The drilling method according to claim 14, wherein a drilling system (10') is provided according to claim 7, wherein, when a deviation is measured: the driving device (40') is brought in its active state by orienting and maintaining it with respect to the soil, the driving device in an angular correction position determined, such that, considered in a horizontal plane, the trajectory correcting direction (DCT) associated to the angular correction position is opposite to the deviation direction (DD); the driving device is brought in its deployed position; the hollow core is displaced with respect to the soil such that the displacement of the hollow core follows the displacement of the driving device.

16. A method for making a column in the soil implementing the drilling method according to claims 14 or 15, wherein a fluid is injected into the well during the ascent of the drilling device in order to form the column in the soil.