Vertical drilling system of auger type provided with a trajectory correcting device

Abstract

The disclosure relates to a system for drilling a vertical well in soil according to a substantially vertical theoretical drilling trajectory comprising a drilling device including a hollow core having a longitudinal axis, the hollow core being provided with a drilling tool; a rotating driving device exhibiting an active state in which the driving device is oriented with respect to the soil in an angular correction position, and a passive state in which the driving device does not modify the displacement trajectory of the drilling device; a device for measuring the deviation of the hollow core; a control device configured to make the driving device swivel when a deviation is measured, in order to bring it in its active state in an angular correction position determined such that, considered in the horizontal plane, the trajectory correcting direction associated with the angular correction position is opposite to the deviation direction.

Claims

1. A system for drilling a well in a soil along a substantially vertical theoretical drilling trajectory, wherein the system includes: a drilling device including a hollow core having a longitudinal axis, the hollow core being provided with a drilling tool; a first device for rotating the hollow core and the drilling tool about the longitudinal axis; a linking element extending inside the hollow core, the linking element including a tremie pipe which presents a lower part provided with at least one injecting hole, the tremie pipe being connected to a fluid supply source; a driving device disposed at a lower end of the tremie pipe; the driving device presenting: an active state in which the driving device is oriented and maintained with respect to the soil in an angular correction position, in such a way as to correct the displacement trajectory of the drilling device along a trajectory correcting direction considered in a horizontal plane, and a passive state in which the driving device does not modify the displacement trajectory of the drilling device; a hollow core deviation measuring device 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 of the drilling device with respect to the substantially vertical theoretical drilling trajectory, said deviation direction being considered in the horizontal plane; a control device configured for, when a deviation is measured in respect of the substantially vertical theoretical drilling trajectory, bringing the driving device in its active state in an angular correction position determined in such a way that, considered in the horizontal plane, the trajectory correcting direction associated with the angular correction position is opposite to the deviation direction; wherein the driving device has a distal end comprising an inclined plane, which inclined plane engages with the soil to correct the displacement trajectory.

2. The drilling system according to claim 1, wherein the control device further includes a computing device for computing the angular correction position based on the deviation direction determined by the hollow core deviation measuring device.

3. The drilling system according to claim 1, wherein the driving device is configured to rotate in the same direction and at the same speed as the hollow core, when said driving device is in the passive state.

4. The drilling system according to claim 3, wherein the drilling device includes a coupling device to lock the rotation of the driving device with respect to the hollow core when said driving device is in the passive state.

5. The drilling system according to claim 1, further including a second device connected to the linking element, for rotating the linking element and the driving device about the longitudinal axis, wherein the linking element is capable of rotating with respect to the hollow core, and wherein 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, wherein the second device is configured to make the driving device 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 claim 1, wherein the driving device is moveable in translation with respect to the hollow core, wherein the drilling system further includes a displacement device for displacing in translation the driving device with respect to the hollow core along the longitudinal axis, in such a way that the driving device presents a deployed position and a retracted position.

8. The drilling system according to claim 7, wherein the displacement device is configured to displace the driving device with respect to the hollow core by jacking, jarring or vibratory driving.

9. The drilling system according to claim 7, wherein, 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 claim 7, wherein the driving device further presents an injecting position wherein the injecting hole is located underneath a lower end of the hollow core.

11. The drilling system according to claim 1, wherein the hollow core deviation measuring device includes an inclination sensor placed in the lower part of the hollow core.

12. The drilling system according to claim 1, wherein further including a member for measuring the depth reached by the drilling device, wherein the hollow core deviation measuring device is configured to measure a deviation distance of the hollow core with respect to a vertical direction, and wherein the control device is configured to bring the driving device in its active state when the ratio of the deviation distance to the depth reached by the drilling device is higher than or equal to a predetermined threshold.

13. The drilling system according to claim 1, wherein the drilling device is an auger.

14. The drilling system according to claim 1, wherein trajectory correcting direction is the direction corresponding to the intersection between the inclined plane and the vertical plane orthogonal to the inclined plane.

15. A method for making a column in a soil comprising a step of drilling a well in the soil along a substantially vertical theoretical drilling trajectory, the method comprising: providing a drilling device including: a hollow core having a longitudinal axis, the hollow core being provided with a drilling tool; a first device for rotating the hollow core and the drilling tool about the longitudinal axis; a linking element extending inside the hollow core, the linking element including a tremie pipe which presents a lower part provided with at least one injecting hole, the tremie pipe being connected to a concrete product source; a driving device disposed at a lower end of the tremie pipe, the driving device presenting: an active state in which the driving device is oriented and maintained with respect to the soil in an angular correction position, in such a way as to correct the displacement trajectory of the drilling device along a trajectory correcting direction considered in a horizontal plane, and a passive state in which the driving device does not modify the displacement trajectory of the drilling device; a hollow core deviation measuring device 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 of the drilling device with respect to the substantially vertical theoretical drilling trajectory, said deviation direction being considered in the horizontal plane; introducing the drilling device in the soil while setting the hollow core into rotation, the driving device being in its passive state; measuring the deviation of the hollow core in order to determine a deviation direction of the drilling device with respect to the vertical theoretical drilling trajectory; and when a deviation higher than a predetermined threshold is measured, bringing the driving device in its active state by orienting it and maintaining it with respect to the soil in an angular correction position, determined such that, considered in a horizontal plane, the trajectory correcting direction associated with the angular correction position is opposite to the deviation direction; and injecting concrete product into the well through the at least one injecting hole during ascent of the drilling device in order to form the column in the soil.

16. The method according to claim 15, wherein the driving device is moveable in translation with respect to the hollow core, wherein the drilling system further includes a displacement device for displacing in translation the driving device with respect to the hollow core along the longitudinal axis, in such a way that the driving device presents a deployed position and a retracted position, wherein said drilling method comprises: when a deviation is measured: bringing the driving device 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 associated to the angular correction position is opposite to the deviation direction; bringing the driving device in its deployed position; and displacing the hollow core with respect to the soil such that the displacement of the hollow core follows the displacement of the driving device.

17. The method according to claim 15, further comprising: measuring the depth reached by the drilling device; measuring a deviation distance of the hollow core with respect to a vertical direction; and bringing the driving device in its active state when the ratio of the deviation distance to the depth reached by the drilling device is higher than or equal to a predetermined threshold.

18. A system for drilling a well in a soil according to a substantially vertical theoretical drilling trajectory, wherein the system includes: a drilling device including a hollow core having a longitudinal axis, the hollow core being provided with a drilling tool; a first device for rotating the hollow core and the drilling tool, around the longitudinal axis; a linking element extending inside the hollow core, the linking element including a tremie pipe which presents a lower part provided with at least one injecting hole, the tremie pipe being connected to a fluid supply source; a driving device disposed at a lower end of the tremie pipe; the driving device presenting: an active state in which the driving device is oriented and maintained with respect to the soil in an angular correction position, in such a way as to correct the displacement trajectory of the drilling device along a trajectory correcting direction considered in a horizontal plane, and a passive state in which the driving device does not modify the displacement trajectory of the drilling device; a hollow core deviation measuring device for identifying a possible deviation between the displacement trajectory of the drilling device and the theoretical drilling trajectory and determining a deviation direction of the drilling device with respect to the theoretical drilling trajectory, said deviation direction being considered in the horizontal plane; 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, the trajectory correcting direction associated with the angular correction position is opposite to the deviation direction; and a member for measuring the depth reached by the drilling device, wherein the hollow core deviation measuring device is configured to measure a deviation distance of the hollow core with respect to a vertical direction, and wherein the control device is configured to bring the driving device in its active state when the ratio of the deviation distance to the depth reached by the drilling device is higher than or equal to a predetermined threshold.

19. A system for drilling a well in a soil according to a substantially vertical theoretical drilling trajectory, wherein the system includes: a drilling device including a hollow core having a longitudinal axis, the hollow core being provided with a drilling tool; a first device for rotating the hollow core and the drilling tool, around the longitudinal axis; a linking element extending inside the hollow core, the linking element including a tremie pipe which presents a lower part provided with at least one injecting hole, the tremie pipe being connected to a fluid supply source; a driving device disposed at a lower end of the tremie pipe; the driving device being moveable in translation with respect to the hollow core, wherein the drilling system further includes a displacement device for displacing in translation the driving device with respect to the hollow core along the longitudinal axis between a first deployed position and a retracted position, wherein said driving device presents: an active state in which the driving device is in the first deployed position and is oriented and maintained with respect to the soil in an angular correction position, in such a way as to correct the displacement trajectory of the drilling device along a trajectory correcting direction considered in a horizontal plane, and a passive state in which the driving device is in the retracted position and does not modify the displacement trajectory of the drilling device; a hollow core deviation measuring device for identifying a possible deviation between the displacement trajectory of the drilling device and the theoretical drilling trajectory and determining a deviation direction of the drilling device with respect to the theoretical drilling trajectory, said deviation direction being considered in the horizontal plane; 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, the trajectory correcting direction associated with the angular correction position is opposite to the deviation direction, wherein, the injecting hole is located above a lower end of the hollow core when the driving device is in the active and passive states.

20. The drilling system according to claim 19, wherein the driving device further presents an injecting position corresponding to a second deployed position of the driving device in which the injecting hole is located underneath the lower end of the hollow core.

21. A system for making a substantially vertical column in a soil along a substantially vertical theoretical drilling trajectory, wherein the system includes: a drilling device including a hollow core having a longitudinal axis, the hollow core being provided with a drilling tool; a first device for rotating the hollow core and the drilling tool about the longitudinal axis; a linking element extending inside the hollow core, the linking element including a tremie pipe which presents a lower part provided with at least one concrete product injecting hole, the tremie pipe being connected to a concrete product supply source; a driving device disposed at a lower end of the tremie pipe; the driving device presenting: an active state in which the driving device is oriented and maintained with respect to the soil in an angular correction position, in such a way as to correct the displacement trajectory of the drilling device along a trajectory correcting direction considered in a horizontal plane, and a passive state in which the driving device does not modify the displacement trajectory of the drilling device; a hollow core deviation measuring device 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 of the drilling device with respect to the substantially vertical theoretical drilling trajectory, said deviation direction being considered in the horizontal plane; a control device configured for, when a deviation is measured in respect of the substantially vertical theoretical drilling trajectory, bringing the driving device in its active state in an angular correction position determined in such a way that, considered in the horizontal plane, the trajectory correcting direction associated with the angular correction position is opposite to the deviation direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure will be better understood upon reading the following description of the embodiments of the disclosure given by way of non limiting examples, with reference to the accompanying drawings, on which:

(2) FIG. 1 is an overall view of a drilling system according to the present disclosure;

(3) FIG. 2 is a detailed view of the upper part of the drilling system of FIG. 1:

(4) FIG. 3 is a detailed view showing the lower part of the drilling device and the driving device according to a first embodiment of the disclosure;

(5) FIG. 4A is a detailed view showing the lower part of the drilling device and the driving device according to a second embodiment of the disclosure, the driving device being in retracted position;

(6) FIG. 4B is a detailed view of the drilling device of FIG. 4A, the driving device being in deployed position;

(7) FIG. 4C illustrates the tremie pipe in injecting position;

(8) FIG. 5A illustrates the drilling system according to a first embodiment of the disclosure, during drilling, the trajectory not being deviated;

(9) FIG. 5B is a projection in the horizontal plane XY of the lower end of the drilling device of FIG. 5A;

(10) FIG. 6A illustrates the drilling system of FIG. 5A, the drilling device having deviated with respect to the vertical theoretical trajectory, the driving device being in its active state in order to correct the deviation;

(11) FIG. 6B is a projection in the horizontal plane XY of the lower end of the drilling device of FIG. 6A;

(12) FIG. 7A illustrates the drilling system of FIG. 6A after correction of the trajectory;

(13) FIG. 7B is a projection in the horizontal plane XY of the lower end of the drilling device of FIG. 7A;

(14) FIG. 8 illustrates a projection in the horizontal plane XY of the lower end of the drilling device when the latter has undergone a deviation according to the axes X and Y;

(15) FIGS. 9 to 12 illustrate a drilling method implemented by the drilling system according to the second embodiment, illustrating a trajectory correction after detecting a deviation;

(16) FIG. 13 is a perspective view of a driving device of the drilling system according to the disclosure;

(17) FIG. 14 is a side view of the driving device of FIG. 13;

(18) FIG. 15 is a diagram illustrating the real trajectory of the drilling system of FIG. 1 during a drilling operation; and

(19) FIG. 16 is an alternative embodiment of the drilling system of FIG. 2 without the second device for setting into rotation.

DETAILED DESCRIPTION

(20) In reference first to FIGS. 1 and 2, it shall be described a system 10 for drilling a well 9 in a soil S, in accordance with the present disclosure, for making columns, such as molded piles.

(21) The drilling system comprises a platform 20 on which is mounted a guiding mast 22 that is substantially vertical in usage position. On this mast is moveably mounted in vertical translation a cart 24 that can be displaced by means of cables 26 associated with a motor that is not represented. The cart 24 bears a first device for setting into rotation 28 comprising a drilling head 29 allowing the setting into rotation of a drilling device 30 including a hollow core 32 provided with a drilling tool 33, in this instance a helical blade extending substantially over the entire length of the hollow core 32. In this example, the drilling device 30 is hence a vertical auger with a hollow core.

(22) It is worth noting that the hollow core 32 extends according to a longitudinal axis L that is substantially vertical.

(23) Inside the hollow core 32 of the drilling device is freely mounted a linking element 36 that is capable of turning with respect to the hollow core around the longitudinal axis L.

(24) In this example, the linking element 36 has the form of a hollow pipe whereof the lower end is equipped with a driving device 40, that shall be described in further detail after.

(25) A moveable plate 42 is connected to the drilling head 29 by means of vertical jacks 44. This plate 42, as illustrated on FIG. 2, receives the upper end 36a of the lining element 36.

(26) In this embodiment, the drilling system further includes a second device for setting into rotation 50, that is connected to the linking element 36, to set into rotation the linking element 36 and the driving device 40 around the longitudinal axis L.

(27) In this example, the linking element is a tremie pipe whereof the upper end is connected to a flexible duct 52 for supplying the pipe with concrete or a thin cement mix.

(28) As is shown on FIG. 2, the first device for setting into rotation 28 includes an engine 51 for setting into rotation the hollow core 32. Furthermore, a turning seal 60 ensures the link through the plate 42 between the upper end of the linking element 36 and the flexible duct 52. It is understood that the jacks 44 allow modifying the axial position of the linking element 36 with respect to the hollow core 32. Furthermore, the cable 26 for the vertical displacement of the drilling head 29 or its drive engine is associated to a linear displacement sensor 62 which allows measuring the vertical displacement of the drilling device. This displacement sensor constitutes a device for measuring the depth H reached by the drilling device.

(29) FIG. 3 illustrates the lower end 30b of the drilling system 30 according to a first embodiment of the disclosure.

(30) In the current phase of drilling the well 9, the linking element 36 and the hollow core 32 can be secured in rotation, for example by a pawl system, such that the driving device 40 and the drilling device 30 rotate together in the same direction, without any relative rotational movement between the linking element 36 and the hollow core 32. According to another alternative, illustrated on FIG. 3, the driving device 40 can be set into rotation, by the second device for setting into rotation 50, according to a rotation direction opposite to the rotation direction of the hollow core 32. As it shall be explained in further detail here-below, the second device for setting into rotation 50 is also capable of locking the rotation of the linking element 36 with respect to the soil S.

(31) On FIGS. 4A and 4B, it has been illustrated a second embodiment of the drilling system according to the disclosure. This second embodiment differs from the first by the fact that the drilling device 30′ includes a coupling device 70, in this example a pawl, to lock the driving device 40′ in rotation with respect to the hollow core 32′. It is also worth noting that the driving device 40′ is moveable in translation with respect to the hollow core 32′ according to the longitudinal axis L. The drilling system 10′, the jacks 44 and the plate 42 constitute 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, such that the driving device 40′ presents a deployed position, illustrated on FIG. 4B, and a retracted position illustrated on FIG. 4A.

(32) Also, when the jacks 44 are in deployed position, the driving device 40′ is in retracted position, whereas the jacks 44 are in on-board position, the driving device 40′ is in deployed position.

(33) The displacement device 43 is furthermore configured for displacing the driving device 40′ with respect to the driving device 32′ by jacking, jarring or vibratory driving.

(34) In order to do this, the displacement device 43 could also be equipped with a vibrating head, not illustrated here.

(35) In this example, the linking element comprises a tremie pipe, which is provided in its lower part, with injecting holes 65 which are concealed by the hollow core 32′ when the driving device 40′ is in retracted position. Preferably, the injecting holes 65 are also concealed by the hollow core when the driving device is in deployed position. In this case, the driving device can also present an injecting or concreting position, illustrated on FIG. 4C, wherein the driving device is deployed even further in such a way that the injecting holes are uncovered so as to allow concreting. In order to do this, the driving device is displaced downwards in translation thanks to the displacement device 43, such that the injecting hole 65 is found underneath the lower end 32′b of the hollow core 32′. In this position, the concrete is injected into the borehole, for example during the ascent of the drilling device 30.

(36) For a more precise explanation about the utility of the injecting holes 65, one may refer to document FR2831205 which describes in detail the method for making a pile using a continuous auger.

(37) On FIG. 16, it has been illustrated an alternative of the second embodiment, wherein the drilling system is devoid of the second device for setting into rotation. In this case, the setting into rotation of the driving device is achieved by the first device for setting into rotation 51 after the linking element is coupled in rotation with the hollow core by the coupling device 70.

(38) In the present disclosure, the focus is mainly on monitoring the drilling trajectory of the drilling device.

(39) By means of FIGS. 13 and 14, it will now be described in a more detailed manner the driving device 40′ of the drilling system 10′ according to the second embodiment of the present disclosure.

(40) The driving device 40′ presents a cylindrical form comprising a first end 40′ provided with a portion for securing to the linking element 36, and a second end part 40′b, opposite to the first end part 40′. The second end part 40′b comprises a front face provided with cutting teeth D that form bulges. The driving device 40′ furthermore includes a section P that is slanted with respect to a plane passing by the axis A of the driving device 40′. The inclination angle between the section P and the axis A of the driving device 40′ is referenced a on FIG. 14. The driving device 40′ further includes protruding squares C that are part of the pawl system 70 described here-above. In this embodiment, the angle α has a value preferably ranging between 15° and 25°.

(41) The function of this specific form of driving device 40′ shall be explained here-below.

(42) It is worth noting that the driving device 40 according to the first embodiment exhibits a form similar to that of the driving device 40′ according to the second embodiment. It is particularly distinguished by the fact that it is devoid of squares C.

(43) Whatever the considered embodiment, the drilling system includes a hollow core deviation measuring device 80 for measuring the deviation of the hollow core 32, 32′ to identify a possible deviation between the displacement trajectory of the drilling device and the theoretical drilling trajectory. In this example, the theoretical drilling trajectory is a vertical trajectory, the displacement trajectory of said drilling device being the real trajectory of the drilling device.

(44) The device 80 for measuring the deviation of the hollow core further includes a deviation sensor 82 that is disposed in the lower part of the hollow core.

(45) The device 80 for measuring the deviation is further configured to determine a possible deviation direction DD of the drilling device with respect to the theoretical drilling trajectory, the deviation direction being considered in a horizontal plane Q that is defined by the frame of reference XY.

(46) Furthermore, in accordance with the disclosure, the driving device 40, 40′ presents an active state wherein the driving device 40, 40′ is oriented and maintained with respect to the soil S, preferably being locked in rotation with respect to said soil S, in an angular correction position, such as to correct the displacement direction T of the drilling device 30, 30′ according to a trajectory correcting direction DCT considered in the horizontal plane Q. The angular orientation and the locking in rotation with respect to the soil of the driving device 40, 40′ are operated by the second device for setting into rotation 50.

(47) As illustrated on FIG. 4B, the trajectory correcting direction DCT corresponds to the intersection between the slanted section P and a plane P′ that is vertical and perpendicular to the section P. As explained hereinabove, the projection in the horizontal plane Q of this trajectory correcting direction shall be focused on.

(48) In reference to FIG. 4B, it is understood that the mating of the driving device 40′ (same for the driving device 40) results in that, in its active state, the driving device 40′ tends, when it is stuck in the soil S, to move in translation according to the trajectory correction DCT illustrated on FIG. 4B, thus resulting in modifying the orientation of the linking element and the hollow core. It is also understood that, according to the angular correction position, considered in a horizontal plane, it is possible to modify the trajectory correcting direction DCT.

(49) When said driving 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 mentioned previously, such that it does not modify the displacement trajectory of the drilling device.

(50) Alternatively, when said driving device is in the passive state, 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 32′.

(51) According to any one of these alternatives, the driving device 40, 40′ in use of the drilling device does not modify the displacement trajectory of the hollow core, which is why it is said that the driving device is in its passive state.

(52) The driving device 40, 40′ is brought in its active state by locking its relative rotational movement with respect to the soil after having oriented it, thanks to the action of the second device for setting into rotation, in the angular position allowing to obtain the required trajectory correcting direction. While keeping on introducing the drilling device, the linking element and the hollow core swivel in a vertical plane passing by the trajectory correcting direction DCT, thus resulting in bringing the longitudinal axis L of the hollow core 32, 32′ according to the theoretical drilling trajectory V.

(53) The drilling system 10, 10′ further includes a control device 100 that is configured to actuate the second device for setting into rotation 50 when a deviation is measured by the device 80, in order to bring the driving device 40, 40′ in its active state by locking it in rotation with respect to the soil in an angular correction position determined in such a way that, considered in the horizontal plane Q, the trajectory correcting direction DCT associated to the angular correction position is opposed to the deviation direction.

(54) In the alternative of the second embodiment, illustrated on FIG. 16, in which the second device for setting into rotation 50 is absent, the control device 100 is configured to bring the driving device in its active state by actuating the first device for setting into rotation after having actuated the coupling device 70.

(55) 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. The angular correction position is determined in such a way that the trajectory correcting direction DCT is opposed to the deviation direction. The control device drives the second device for setting into rotation in order to bring the driving device in the required angular correction position.

(56) The deviation sensor 82 is configured to measure a deviation distance d of the hollow core 32, 32′ with respect to a vertical direction. This distance is considered in a horizontal plane passing by the deviation sensor. Furthermore, the control device is configured to actuate the second device for setting into rotation when the ratio of the deviation distance d on the depth H reached by the drilling device is higher than or equal to a threshold that can depend on the reached depth. By way of example, this threshold can be 0.3%.

(57) This shall be explained in further detail by means of FIGS. 5A to 8 which describe a method for drilling a well in the soil S according to a theoretical drilling trajectory V, in this instance vertical, using the drilling system according to the first embodiment of the disclosure.

(58) On FIG. 5A, it has been illustrated the drilling device 30. During drilling, the longitudinal axis L of the hollow core being parallel to the theoretical drilling direction V, these are hence both vertical. The driving device 40 is in its passive state and the driving device is set into rotation by the second device for setting into rotation 50 in the opposite direction to the rotational direction of the hollow core 32.

(59) The drilling device 10 is hence introduced into the soil while setting the hollow core 32 into rotation.

(60) The possible deviation of the hollow core 32 is measured by means of the device 80 for measuring deviation of the hollow core in order to determine a deviation direction DD of the drilling device with respect to the theoretical drilling trajectory V.

(61) On FIG. 5A, no deviation is detected. Also, considered in the horizontal plane Q, the driving device 40 is found in the centre of the frame of reference XY illustrated on FIG. 5B.

(62) During drilling, as illustrated schematically on FIG. 6A, a deviation illustrated by a deviation distance d is measured. This deviation distance d, measured at depth H, for example 5m, being higher than a predetermined threshold, for example 2 cm, namely 0.4%, the control device drives the second device for setting into rotation such as to bring the driving device 40 in its active state by orienting it then locking it in rotation with respect to the soil S in an angular correction position determined, such that, considered in the horizontal plane Q, the trajectory correcting direction DCT associated to the angular correction position is opposed to the deviation direction DD. It is understood that the deviation illustrated on FIG. 6A is schematic and exaggerated to facilitate the comprehension of the disclosure.

(63) Without departing from the scope of the present disclosure, other threshold values could be chosen by the skilled person depending on the required drilling precision.

(64) In the example of FIG. 6B, in order to facilitate the comprehension, the deviation direction DD as well as the trajectory correcting direction DCT extend according to the axis X. However, these two directions could however not be parallel.

(65) Finally, on FIG. 7A, it has been illustrated the position of the hollow core 32 after the latter is aligned again with the theoretical drilling trajectory V. The driving device is then brought in its passive state, for example by making it rotate in the opposite direction to the rotational direction of the hollow core 32. The drilling is hence pursued until a deviation higher than a predetermined threshold is measured again.

(66) On FIG. 8, it has been illustrated a case where the deviation direction extends along a non parallel direction to axes X and Y. The operating principle is identical. The driving device is put in its active state by orienting it and locking it with respect to the soil, such that the trajectory correcting direction is opposed to the detected deviation direction. The trajectory correcting direction DCT is determined in such a way as to correct the verticality of the hollow core during the thrusting of the drilling device into the soil.

(67) On FIGS. 9 to 12, it has been illustrated a method for drilling a well according to a second implementation embodiment, using the drilling system according to the second embodiment illustrated on FIGS. 4A and 4B.

(68) This second implementation embodiment differs from the first one by the fact that, when a deviation higher than a predetermined threshold is measured, the driving device 40′ is brought in its active state and in its deployed position, illustrated on FIG. 11, for example by translation and vibratory driving. Then, 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, by which the verticality of the trajectory of the hollow core is corrected such as illustrated on FIG. 12.

(69) The methods of drilling wells according to the first and second implementing embodiments, can advantageously be used as part of a method for making a column, such as a pile, a method wherein a fluid is injected into the well at the moment of the ascent of the drilling device in order to form the column in the soil.

(70) Finally, on FIG. 14, it has been illustrated the deviation curves of the drilling tool according to the drilling depth. The curve GX illustrates the deviation according to the axis X whereas the curve GY illustrates the deviation according to the axis Y, and the curve GT illustrates the total deviation of the drilling device.

(71) It is understood that the driving device is in its passive state up to a depth of around 8 meters, after which it is put in its active state up to around a depth of 12 meters, where it returns to its passive state. Hence, it is noted that the maximum deviation distance is about 3 cm for a depth ranging between 8 and 10 meters. In other words, during the drilling operation, the deviation expressed in percentage is at 0.375%, at maximum and hence lower than the critical limit of 0.5%.