Method for carrying out an excavation with trajectory correction

Abstract

Method for Excavating with Trajectory Correction: A method for excavating along a predetermined trajectory, in which drilling is carried out by rotating a drill pipe (12) using a rotation device (16), in which, during the drilling step, a deviation of the drill pipe is determined and, if said deviation exceeds a predetermined deviation threshold, a corrected trajectory (X'') is determined, an angular correction position of the trajectory correction head is determined, said trajectory correction head is placed in said angular correction position; and the trajectory correction head is vibrated using a vibration device (18), so as to move the trajectory correction head along the corrected trajectory. Figure for the abstract: Fig. 1.

Description

Title of the invention: Method for carrying out an excavation with trajectory correction Technical field

[0001] The present invention relates to the technical field of methods for directional drilling in the ground. The present invention relates more specifically to a method for carrying out an excavation in a ground along a predetermined trajectory, in which the drilling trajectory is corrected in the event of deviation from said predetermined trajectory. Directional drilling is understood to mean drilling in which the drilling trajectory is corrected in the event of deviation of said drilling trajectory from the predetermined trajectory. Prior art

[0002] Directional drilling methods are known, implemented by means of a drilling device comprising a drilling tube and a rotation device configured to rotate the drilling tube in order to carry out the excavation. This drilling device further comprises a trajectory correction head and a device for projecting a drilling fluid. In the event of deviation of the drilling trajectory from a predetermined trajectory, this method provides for orienting the trajectory correction head according to a correction position and pushing on the drilling tube to drive the head into the ground while projecting drilling fluid under high pressure, in order to destructure the ground. The trajectory correction head is then moved according to a corrected trajectory.

[0003] A disadvantage of this known method is that it does not allow the drilling trajectory to be corrected when drilling hard soils, such as rocky soils. Indeed, the projection of drilling fluid does not allow such hard soils to be effectively deconstructed and the trajectory correction head cannot be driven into this soil or risks being damaged.

[0004] Furthermore, this method according to the prior art provides for changing the trajectory correction head each time a soil of a different nature is encountered, in order to adapt the type of trajectory correction head used to the nature of the soil being drilled. This change of tooling generates a significant loss of time and proves to be particularly costly. In other words, this method according to the prior art does not allow continuous directional drilling to be carried out when the nature of the soil being drilled changes.

[0005] This method also does not allow directional drilling to be continued at the interface between two portions of soil of different natures. Statement of the invention

[0006] An aim of the present invention is to propose a method for carrying out an excavation which overcomes the aforementioned drawbacks.

[0007] To this end, the invention relates to a method for carrying out an excavation in a ground along a predetermined trajectory in which a drilling device is provided comprising: a drill pipe having a distal end portion that is provided with a trajectory correction head; a device for rotating the drill pipe; and a drill pipe vibrating device configured to vibrate the trajectory correction head, the method comprising a step in which drilling is carried out in said ground by rotating the drilling tube by means of the rotating device, wherein, after starting the drilling step, a deviation of the drill pipe from said predetermined trajectory is determined and, if said deviation exceeds a predetermined deviation threshold, the following steps are carried out: - a corrected trajectory is determined for the drilling tube from said determined deviation; - an angular correction position of the trajectory correction head is determined from said determined corrected trajectory; - said trajectory correction head is placed in said angular correction position; and - the trajectory correction head is vibrated using the vibration device, so as to move the trajectory correction head along the corrected trajectory.

[0008] The predetermined trajectory corresponds to a reference trajectory, along which the excavation is desired to extend. In a non-limiting manner, the predetermined trajectory may be substantially horizontal, inclined relative to the horizontal, vertical or even inclined relative to the vertical. The predetermined trajectory may be rectilinear or curvilinear.

[0009] The drilling tube advantageously extends in a longitudinal direction. It may be hollow or solid. It may comprise one or more tubular elements connected to each other, in order to increase the length of the drilling tube. Consequently, the term "drilling tube" means both a single drilling tube and a plurality of tubular elements fixed end to end, for example by screwing.

[0010] The rotation device is preferably connected to a proximal end portion of the drill pipe. The vibration device is preferably connected to a proximal end portion of the drill pipe.

[0011] In a non-limiting manner, the vibration device may be separate from the rotating device.

[0012] The vibration device is advantageously configured to generate longitudinal oscillations in the drill pipe. The longitudinal oscillations generate compression waves propagating in the longitudinal direction of the drill pipe, from its proximal end portion to its distal end portion. In other words, these compression waves propagate from the vibration device to the trajectory correction head.

[0013] Preferably, in the absence of vibration of the trajectory correction head, the rotating drilling tube describes a substantially rectilinear trajectory. Its trajectory may however deviate from the predetermined trajectory, in particular due to irregularities in the ground being drilled or the high rotation speed of the drilling tube.

[0014] Preferably, the drill pipe comprises a cutting tool. The cutting tool is configured to cut the ground when said drill pipe is rotated. The cutting tool is advantageously mounted at the distal end portion of the drill pipe. In a non-limiting manner, the trajectory correction head may be separate from the cutting tool. Alternatively, the cutting tool may comprise, or even be constituted by, said trajectory correction head.

[0015] Advantageously, the steps of determining a deviation of the drilling tube, determining a corrected trajectory for the drilling tube, determining an angular correction position of the trajectory correction head, placing said trajectory correction head in said angular correction position and setting the trajectory correction head into vibration, can be carried out during drilling or after drilling.

[0016] The step of determining the deviation of the drilling tube from the predetermined trajectory advantageously comprises a step of measuring(s) the position of the drilling tube, for example a measurement of the inclination, orientation and / or geographical position of the drilling tube.

[0017] The corrected trajectory is advantageously determined from a comparison between the determined deviation and the predetermined trajectory. Said corrected trajectory is determined so as to counter the deviation and return the drilling tube to the predetermined trajectory.

[0018] The angular position of the trajectory correction head preferably comprises the inclination of the trajectory correction head relative to the longitudinal direction of the drill pipe and / or the orientation of the trajectory correction head about an axis along which it extends. The step of determining the angular correction position of the trajectory correction head advantageously comprises a step of determining a correction inclination of the trajectory correction head. trajectory correction, for example with respect to the longitudinal direction of the drill pipe and / or a step of determining a correction orientation of the trajectory correction head, for example around an axis along which the trajectory correction head extends.

[0019] The vibration of the trajectory correction head placed in the angular correction position causes it to move along the corrected trajectory. The drill pipe is consequently moved along this corrected trajectory, which tends to bring it back into the predetermined trajectory. The deviation of the drill pipe is compensated for and its trajectory is therefore corrected. In other words, the vibration of the trajectory correction head placed in the angular correction position causes a controlled deviation of the drill pipe towards its predetermined trajectory.

[0020] In a non-limiting manner, the steps of determining a corrected trajectory for the drill pipe, determining an angular correction position of the trajectory correction head, placing said trajectory correction head in said angular correction position and vibrating the trajectory correction head, can be carried out by rotating the drill pipe or by interrupting the rotation of said drill pipe.

[0021] Preferably, the trajectory correction head has an active position in which its vibration causes the drilling tube to move along the corrected trajectory. In other words, in the active position, the trajectory correction head makes it possible to deflect the drilling tube and correct its trajectory. Preferably, the trajectory correction head also has an inactive position in which it is configured not to modify the trajectory of the drilling tube when the drilling tube is vibrated.

[0022] In a non-limiting manner, the trajectory correction head further advantageously has a drilling position in which it is configured not to modify the trajectory of the drilling tube when said drilling tube is rotated. This drilling position of the trajectory correction head advantageously depends on the nature of the trajectory correction head used. In a non-limiting manner, said drilling position may correspond to the active position or even to the inactive position of the trajectory correction head.

[0023] The trajectory correction head is advantageously placed in an inactive position when it is not vibrating. One advantage is to prevent it from deflecting the drilling tube during drilling when this is not desirable, and in particular when the latter is rotating.

[0024] Thanks to the invention, in the absence of deviation, drilling is carried out by rotating the drilling tube, which allows the excavation to be carried out quickly, reducing wear on the drilling tube and the trajectory correction head. In the event of deviation of the drill pipe from its predetermined trajectory, the vibrating drill head allows the deviated trajectory to be corrected, in order to bring the drill pipe back into its predetermined trajectory. The vibration of the trajectory correction head allows the trajectory of the drill pipe to be corrected in soft soil, for example sandy soil, but also in hard soil, for example rocky soil. Indeed, the vibration of the trajectory correction head provides the energy necessary for drilling hard soils, for example rocky soils, which can be difficult to drill by rotating the drill pipe or by projecting a drilling fluid.

[0025] In other words, the invention makes it possible to carry out directional drilling in hard soils. Furthermore, the invention makes it possible to continue correcting the trajectory of the drilling tube, even when a change in the nature of the soil is encountered. Indeed, vibratory drilling for moving the trajectory correction head is suitable for all types of soil, whether soft or hard. It is therefore not necessary to change the type of trajectory correction head when the nature of the soil to be drilled changes. The method according to the invention allows continuous directional drilling, even at the interface between two soils of different natures.

[0026] Furthermore, the vibration of the trajectory correction head also allows the creation of an annular space around said trajectory correction head facilitating trajectory correction.

[0027] Preferably, but in a non-limiting manner, the movement of the trajectory correction head in the ground, by vibrating the latter, is accompanied by a projection of drilling fluid under pressure.

[0028] Preferably, the vibration of the trajectory correction head is interrupted when the trajectory of the drill pipe corresponds to the predetermined trajectory. Drilling can then be continued by means of the rotated drill pipe. Alternatively, the vibration can be interrupted after the trajectory correction head has been moved a predetermined distance according to the corrected trajectory.

[0029] Advantageously, during drilling, the rotation of the drill pipe is interrupted at least once before determining the deviation of the drill pipe from said predetermined trajectory, and the drill pipe is put back into rotation so as to drive said drill pipe into the ground along said corrected trajectory, after having moved the trajectory correction head along the corrected trajectory. An advantage is that it facilitates and improves the taking of measurements during trajectory correction. The measurements and the movement of the trajectory correction head along the corrected trajectory are not disturbed by the rotation of the drill pipe. This makes it possible to improve the accuracy of the trajectory correction.

[0030] It is understood that the trajectory correction of the drilling tube is then carried out by vibrating the trajectory correction head, without rotating the drilling tube.

[0031] Advantageously, the vibration of the trajectory correction head is interrupted after having moved the trajectory correction head along the corrected trajectory, and before restarting the rotation of the drilling tube.

[0032] Advantageously, the deviation of the drill pipe from said predetermined trajectory is determined several times during drilling, the drill pipe being driven into the ground to a predetermined depth between each determination of the deviation of the drill pipe. One advantage is to correct the trajectory of the drill pipe several times so that the drill pipe follows a trajectory that is all the closer to the predetermined trajectory. Another advantage is to prevent the drill pipe from deviating excessively from the predetermined trajectory. The accuracy of the drilling is improved.

[0033] In other words, the determination of the deviation of the drilling tube and the trajectory correction is carried out at regular intervals, each time a drilling of a predetermined depth is carried out, for example every six meters of drilling. The trajectory correction is advantageously iterative.

[0034] Advantageously, the deviation of the drilling tube is determined in real time.

[0035] Preferably, the step of determining the corrected trajectory for the drill pipe comprises a step according to which an extrapolated deviated trajectory of the drill pipe is calculated from the determined deviation of the drill pipe. One advantage is to correct the trajectory of the drill pipe before it actually deviates significantly from its predetermined trajectory. The trajectory of the drill pipe is maintained all the closer to its predetermined trajectory.

[0036] This extrapolated deviated trajectory is a projection, corresponding to the predicted trajectory of the drill pipe if drilling by rotating the drill pipe is continued and in the absence of correction of its trajectory. The extrapolated deviated trajectory is preferably determined from the determined deviation of the drill pipe and possibly from parameters linked to the ground to be drilled.

[0037] Preferably, the trajectory correction head is also set into vibration during drilling by rotating the drill pipe. One advantage is to facilitate and accelerate the drilling of the excavation by combining the energy provided by rotating the drill pipe and the energy provided by vibrating the cutting head.

[0038] Advantageously, the step of vibrating the trajectory correction head is carried out by vibrating the drilling tube. The vibration of the drilling tube causes the vibration of the trajectory correction head which is arranged at its distal end portion. The rotation device is then advantageously connected to a proximal end portion of the drill pipe.

[0039] Advantageously, a drilling fluid is injected into the ground from the distal end portion of the drill pipe at least when the trajectory correction head is vibrating. One advantage is to facilitate the movement of the trajectory correction head in the ground when correcting the trajectory of the drill pipe. The drilling fluid is advantageously conveyed to the distal end portion of the drill pipe via the interior of said drill pipe.

[0040] In a non-limiting manner, the drilling fluid can also be injected into the ground during drilling by rotating the drilling tube.

[0041] Preferably, the deviation of the drill pipe from the predetermined trajectory is determined using a measuring device comprising at least one of the following measuring members: a magnetic probe, a gyrometer, an accelerometer, an inclinometer, an odometer or a combination thereof. For example, the measuring member may comprise an inertial unit comprising at least one gyrometer, at least one accelerometer, at least one inclinometer and / or at least one odometer.

[0042] Preferably, determining the deviation of the drill pipe from the predetermined trajectory comprises a step of measuring positioning data of the drill pipe, for example the geographic position, inclination or orientation of the drill pipe.

[0043] Preferably, but not limited to, said measuring member is mounted on the drill pipe. Alternatively, the measuring member may be introduced into the excavation when it is desired to determine the deviation of the drill pipe.

[0044] Preferably, the method further comprises a step of calibrating the measuring member.

[0045] The use of a gyrometer makes it possible to overcome interference that can be generated by metallic elements present in the ground.

[0046] Preferably, the trajectory correction head comprises a beveled tool, a paddle tool, an articulated rod, a bent rod or a drill bit or a combination of these.

[0047] The beveled tool is also called a slanted face tool. It comprises a beveled leading edge configured to deflect the trajectory correction head when it is driven into the ground by vibration.

[0048] The paddle tool is also called a spatula tool. This paddle tool comprises a paddle whose inclination and orientation can be modified in order to adjust the deviation of the trajectory correction head during its movement by vibration.

[0049] The bent rod comprises a first rod portion and a second rod portion pivotally mounted relative to the first rod portion. A drill bit is advantageously mounted at the end of the second rod portion. The inclination of the second rod portion makes it possible to adjust the deviation of the trajectory correction rod during its movement by vibration.

[0050] A drill bit preferably comprises a plurality of pivoting wheels provided with cutting teeth.

[0051] The invention further relates to an installation for carrying out an excavation in a ground along a predetermined trajectory, the installation comprising: a drill pipe having a distal end portion that is provided with a trajectory correction head; a device for rotating the drilling tube; a drill pipe vibrating device configured to vibrate the trajectory correction head; a control device configured to control rotation of the drill pipe by means of the rotation device in order to perform drilling; a measuring device configured to determine a deviation of the drill pipe relative to said predetermined trajectory and allowing, if said deviation exceeds a predetermined deviation threshold, to determine a corrected trajectory for the drill pipe from said determined deviation and to determine an angular correction position of the trajectory correction head from said determined corrected trajectory, the control device being further configured to place said trajectory correction head in said angular correction position and to control the vibration of the trajectory correction head using the vibration device, so as to move the trajectory correction head according to the corrected trajectory.

[0052] In a non-limiting manner, the measuring device may be used by an operator on the construction site to determine said corrected trajectory for the drill pipe and the angular correction position of the correction head. Alternatively, and in a non-limiting manner, said measuring device may be configured to determine said corrected trajectory for the drill pipe and said angular correction position of the trajectory correction head. The operator then does not intervene in this determination of the corrected trajectory and the angular correction position.

[0053] Advantageously, the control device is configured to control at least once the interruption of the rotation of the drilling tube during drilling, before determining the deviation of the drilling tube with respect to said predetermined trajectory and the control device is configured to control again the rotation of the drilling tube so as to drive said drilling tube into the ground. according to said corrected trajectory, after having moved the trajectory correction head according to the corrected trajectory.

[0054] Preferably, the distal end portion of the drill pipe is further provided with a cutting tool, the trajectory correction head projecting radially from the cutting tool. The cutting tool is configured to cut the ground when the drill pipe is rotated, in order to carry out the drilling. The cutting tool is advantageously arranged at the distal end portion of the drill pipe.

[0055] Advantageously, the trajectory correction head is fixed relative to the cutting tool.

[0056] Preferably, the trajectory correction head is removably mounted at said distal end portion of the drilling tube.

[0057] Preferably, the drill pipe has a proximal end portion and the vibration device comprises a vibration generator connected to said proximal end portion of the drill pipe, the trajectory correction head being vibrated by vibrating the drill pipe by means of the vibration generator. The vibration generator makes it possible to generate compression waves propagating in the drill pipe.

[0058] Advantageously, the drilling tube extends in a longitudinal direction and, considered with respect to a longitudinal plane comprising said longitudinal direction, the trajectory correction head is asymmetrical. This asymmetry of the trajectory correction head makes it possible to move it along the corrected trajectory when the drilling tube is pushed in its longitudinal direction.

[0059] Preferably, the trajectory correction head comprises a beveled tool, a paddle tool, an articulated rod, an angled rod or a drill bit or a combination thereof.

[0060] Preferably, the measuring device comprises at least one measuring member chosen from: a magnetic probe, a gyrometer, an accelerometer, an inclinometer, an odometer or a combination of these.

[0061] Preferably, the trajectory correction head or the drilling tube comprises the measuring member. The measuring member is advantageously mounted on the drilling tube or on the trajectory correction head. Brief description of the drawings

[0062] The invention will be better understood on reading the following description of an embodiment of the invention given by way of non-limiting example, with reference to the appended drawings, in which:

[0063] [Fig.l] [Fig.l] illustrates an embodiment of an installation according to the invention;

[0064] [Fig.2] [Fig.2] illustrates a drilling step of the method according to the invention, by putting rotating the drill pipe;

[0065] [Fig.3] [Fig.3] illustrates a step of determining a deviated trajectory ex trapole of the drilling tube of the method according to the invention;

[0066] [Fig.4] [Fig.4] illustrates a step of determining a corrected trajectory of the method according to the invention;

[0067] [Fig.5] [Fig.5] illustrates a step of displacement by vibrating the head of trajectory correction of the method according to the invention;

[0068] [Fig.6] [Fig.6] illustrates a new drilling step of the method according to the invention, after putting the drill pipe back into rotation;

[0069] [Fig.7] [Fig.7] illustrates an excavation carried out by implementing the method according to the invention; and

[0070] [Fig.8] [Fig.8] illustrates a variant of the installation according to the invention in which The trajectory correction head includes an angled rod and a drill bit. Description of the embodiments

[0071] The invention relates to a method for carrying out an excavation in a ground along a predetermined trajectory. The invention also relates to an installation for carrying out an excavation in a ground along a predetermined trajectory. This installation is suitable for implementing the method according to the invention.

[0072] [Fig. 1] illustrates an embodiment of an installation 8 for carrying out an excavation E along a predetermined trajectory X.

[0073] As illustrated in [Fig.l], the installation 8 comprises a drilling device 10. The drilling device 10 comprises a drilling tube 12 having a proximal end portion 12a and a distal end portion 12b. The drilling tube 12 extends in a longitudinal direction Y.

[0074] The distal end portion 12b of the drill pipe is provided with cutting teeth 13. The distal end portion 12b of the drill pipe is further provided with a trajectory correction head 14. In this non-limiting example, the trajectory correction head 14 projects radially from the distal end portion 12b of the drill pipe. In this non-limiting example, the trajectory correction head 14 and the cutting teeth 13 form a cutting tool. Alternatively, and in a non-limiting manner, the trajectory correction head could be separate from the cutting tool and project from said cutting tool.

[0075] In this non-limiting example, the trajectory correction head 14 comprises a paddle tool, also called a spatula tool, comprising a paddle 15. Said paddle 15 is inclined relative to the longitudinal direction of the drill pipe 12. The inclination and orientation of this paddle 15 can be adjusted. In a non-limiting manner, the trajectory correction head could comprise a drill bit and / or a bent rod, in addition to or replacing the pallet 15.

[0076] Said trajectory correction head 14 is asymmetrical, in particular considered with respect to a longitudinal plane comprising the longitudinal direction Y of the drilling tube. The trajectory correction head 14 is removably mounted at the distal end portion 12b of the drilling tube 12.

[0077] [Fig. 8] illustrates a variant of the installation 8 according to the invention, in which the trajectory correction head 14 comprises a bent rod 21 and a drill bit 23. This bent rod 21 comprises a first portion and a second portion pivotally mounted relative to the first portion. The second portion can therefore be inclined relative to the first portion in order to adjust the trajectory of the drilling tube 12 when it is set into vibration.

[0078] Referring again to [Fig. 2], it can be seen that the drilling device 10 further comprises a device 16 for rotating the drilling tube 12. The rotation device 16 is connected to the proximal end portion 12a of the drilling tube 12.

[0079] The drilling device 10 also comprises a device 18 for vibrating the drilling tube, comprising a vibration generator. The vibration device 18 is also connected to the proximal end portion 12a of the drilling tube 12 and is configured to generate longitudinal oscillations in the drilling tube. Such longitudinal oscillations generate compression waves propagating in the longitudinal direction of the drilling tube, from its proximal end portion to its distal end portion.

[0080] The installation 8 further comprises a measuring device 20 comprising, in this non-limiting example, a measuring member 22 mounted on the drilling tube 12 and a computer 24 with which the measuring member 22 communicates. In this example, the measuring member 22 comprises an inertial unit comprising gyrometers, accelerometers, inclinometers and odometers making it possible to measure positioning data of the drilling tube.

[0081] The installation 8 also comprises a control device 26 communicating, in this non-limiting example, with the vibration device 18, with the rotation device 16, with the computer 24 and with the trajectory correction head 14.

[0082] Using figures 1 to 7, we will describe a non-limiting embodiment of the method for carrying out an excavation in a ground along a predetermined trajectory according to the invention.

[0083] According to a first step, illustrated in [Fig.l], an installation 8 is provided comprising the drilling device 10. In this non-limiting example, the soil S in which the excavation is to be carried out comprises a first portion of soil Si and a second portion of soil S2. The first portion of soil Si is loose and consists mainly of sand. The second portion of soil S2 is hard and rocky soil. The excavation will be carried out in a vertical wall formed by soil S.

[0084] The excavation must be carried out along a predetermined trajectory X which is, in this non-limiting example, substantially horizontal.

[0085] As illustrated in [Fig.2], drilling of the ground S is carried out, initiated in the first portion of ground Si, by rotating the drilling tube 12 by means of the rotation device 16. The rotation of the drilling tube 12 is controlled by means of the control device 26. The drilling tube is rotated about its longitudinal direction Y and makes it possible to drill the first portion of ground Si. In this non-limiting example, the rotation of the drilling tube is not accompanied by vibration of the drilling tube. Furthermore, during this drilling by rotating the drilling tube, the trajectory correction head 14 is placed in the drilling position so that it does not modify the trajectory of the drilling tube when it is rotated. In this non-limiting example, this drilling position corresponds to an active position of the trajectory correction head 14.The cutting teeth of the cutting tool 13, as well as the trajectory correction head 14, set in rotation, make it possible to drill the ground.

[0086] In a non-limiting manner, after drilling the ground S to a predetermined depth, for example three meters, the rotation of the drilling tube 12 is interrupted. A possible deviation of the drilling tube 12 relative to the predetermined trajectory X is then determined using the measuring device 20. In this example, the deviation of the drilling tube 12 is measured using the measuring member 22. The inertial unit of the measuring member makes it possible in particular to precisely determine positioning data of the drilling tube 12 such as its position, its orientation and its inclination and to calculate its deviation relative to the predetermined trajectory X from these positioning data.

[0087] In this non-limiting example, and as illustrated in [Fig. 3], an extrapolated deviated trajectory X' of the drilling tube 12 is then calculated using the measuring device 20 from the measured deviation of the drilling tube. This extrapolated deviated trajectory is a projection of the trajectory of the drilling tube 12 in the case where the rotary drilling would be continued without trajectory correction. This extrapolated deviated trajectory X' is illustrated in [Fig. 3], and is here directed downwards. The calculation of the extrapolated deviated trajectory X' also implements parameters linked to the ground S and adjustable coefficients, for example during calibration of the measuring device. From this extrapolated deviated trajectory X', an extrapolated deviated drilling F' is also deduced, corresponding to the drilling that would be obtained without trajectory correction.

[0088] In the event that the deviation exceeds a predetermined deviation threshold, we determine then a corrected trajectory X” for the drill pipe, from the determined deviation of the drill pipe, and more precisely from the extrapolated deviated trajectory X'. This corrected trajectory X” is illustrated in [Fig.4] and is directed upwards. This corrected trajectory corresponding to a trajectory making it possible to counter the deviation of the drill pipe, and in particular the extrapolated deviated trajectory X', and therefore tending to bring the pipe back along the predetermined trajectory X.

[0089] From this determined corrected trajectory X”, an angular correction position of the trajectory correction head 14 is determined, using the measuring device 20, and in particular the computer 24. This angular correction position is a function of the nature of the trajectory correction head as well as the ground to be drilled. As can be seen in [Fig.4], said trajectory correction head 14 is then placed in said angular correction position. In this non-limiting example, the orientation and inclination of the pallet 15 of the trajectory correction head 14 are adjusted so that the pallet is inclined upwards. In a non-limiting manner, placing in the angular correction position may comprise adjusting the position, orientation and inclination of said trajectory correction head 14.The angular correction position corresponds to an active position of the trajectory correction head, in which it allows the trajectory of the drill pipe to be deflected when it vibrates. In [Fig.4], we see that from the corrected trajectory X” we deduce an extrapolated corrected drilling F”, which extends along the predetermined trajectory X.

[0090] As shown in [Fig.5], the trajectory correction head 14 is then vibrated using the vibration device 18. More precisely, the vibration of the drilling tube 12 is controlled by the vibration device 18, using the control device 26. The vibration device 18 generates longitudinal oscillations in the drilling tube generating compression waves propagating in the longitudinal direction Y of the drilling tube 12. These compression waves propagate from the proximal end portion 12a to the distal end portion 12b of the drilling tube. In other words, the compression waves propagate from the vibration device 18 to the trajectory correction head 14 which is thus vibrated.

[0091] A thrust is exerted on the drilling tube. The drilling tube 12 and the trajectory correction head 14, set in vibration, are then driven into the ground S and moved along the corrected trajectory X”, taking into account the angular correction position of the trajectory correction head. The vibration of the trajectory correction head provides it with the energy necessary to enable it to cut the ground and to drive into the ground.

[0092] In a non-limiting manner, the vibration of the trajectory correction head 14 may be accompanied by an injection of drilling fluid into the ground from the distal end portion 12b of the drilling tube or at the level of the trajectory correction head 14.

[0093] Thanks to the invention, this vibration of the trajectory correction head makes it possible to correct the trajectory of the drilling tube 12 through the first portion of soil Si which is loose, but also through the second portion of soil S2 which is hard and rocky. The vibrational energy supplied to the trajectory correction head 14 makes it possible to effectively deconstruct the soil, and in particular the rocky portion of soil S2 to allow it to be driven in. The movement of the correction head through these two portions of soil is illustrated by the passage from [Fig.4] to [Fig.5] and from [Fig.5] to [Fig.6]. In particular, the risk of damage to the trajectory correction head 14 is reduced. Furthermore, it is not necessary to change the type of trajectory correction head 14 when passing from the first portion of soil Si to the second portion of soil S2.Furthermore, the movement of the trajectory correction head, and therefore of the drilling tube 12, along the corrected trajectory X” can be continued continuously, even at the interface between the two portions of ground.

[0094] The movement of the trajectory correction head 14 and the drilling tube along the corrected trajectory X” makes it possible to counter the deviation of the drilling tube from the predetermined trajectory. Preferably, said trajectory correction head 14 is moved along said corrected trajectory over a predetermined distance.

[0095] Following this movement, it is considered that the drilling tube is brought back into its predetermined trajectory X. The vibration of the drilling tube 12 and the trajectory correction head 14 is then interrupted. As illustrated in [Fig.6], the drilling tube is restarted by means of the rotation device 16. The drilling tube is driven along the corrected trajectory, advantageously rejoining the predetermined trajectory. The trajectory correction head 14 is advantageously configured so as not to deflect the drilling tube when the latter is rotated and performs the drilling. The drilling is continued until the excavation is completed. Thanks to the trajectory correction carried out, the final excavation extends substantially along the predetermined trajectory X.

[0096] In this non-limiting example, an additional tubular element 17 is added so that the drilling tube 12 comprises two tubular elements connected to each other, end to end.

[0097] Preferably, the preceding steps illustrated in Figures 3 to 6 for correcting the trajectory of the drilling tube 12 can be repeated several times. In particular, these steps can be carried out at regular intervals, each time the drilling tube 12 is driven into the ground S to a predetermined depth.

Claims

Claims

1. A method of carrying out an excavation in a ground (S) along a predetermined trajectory in which a drilling device (10) is provided comprising: a drilling tube (12) having a distal end portion (12b) which is provided with a trajectory correction head (14); a device (16) for rotating the drilling tube;and a device (18) for vibrating the drilling tube configured to vibrate the trajectory correction head, the method comprising a step in which drilling is carried out in said ground by rotating the drilling tube by means of the rotation device, wherein, after starting the drilling step, a deviation of the drilling tube from said predetermined trajectory is determined and, if said deviation exceeds a predetermined deviation threshold, the following steps are carried out: determining a corrected trajectory (X”) for the drilling tube from said determined deviation; determining a correction angular position of the trajectory correction head from said determined corrected trajectory; placing said trajectory correction head in said correction angular position;and the trajectory correction head is vibrated using the vibration device, so as to move the trajectory correction head along the corrected trajectory.;

2. Method according to claim 1, wherein, during drilling, the rotation of the drilling tube (12) is interrupted at least once before determining the deviation of the drilling tube from said predetermined trajectory (X), and wherein the drilling tube is restarted in rotation so as to drive said drilling tube into the ground along said corrected trajectory (X”), after having moved the trajectory correction head along the corrected trajectory.

3. A method according to claim 1 or 2, wherein the deviation of the drill pipe (12) from said predetermined trajectory (X) is determined repeatedly during drilling, the drill pipe being driven into the ground (S) to a predetermined depth between each determination of the deviation of the drill pipe.

4. A method according to any one of claims 1 to 3, wherein the step of determining the corrected trajectory (X”) for the drill pipe (12) comprises a step of calculating an extrapolated deviated trajectory (X') of the drill pipe from the determined drill pipe deviation.

5. Method according to any one of claims 1 to 4, in which the trajectory correction head (14) is also vibrated during rotation of the drilling tube (12).

6. A method according to any one of claims 1 to 5, wherein the step of vibrating the trajectory correction head (14) is carried out by vibrating the drill pipe (12).

7. A method according to any one of claims 1 to 6, wherein a drilling fluid is injected into the ground from the distal end portion of the drill pipe at least when the trajectory correction head (14) is vibrated.

8. Method according to any one of claims 1 to 7, in which the deviation of the drilling tube (12) from the predetermined trajectory (X) is determined using a measuring device (20) comprising at least one of the following measuring members (22): a magnetic probe, a gyrometer, an accelerometer, an inclinometer, an odometer or a combination thereof.

9. A method according to any one of claims 1 to 8, wherein the trajectory correction head (14) comprises a bevel tool, a paddle tool (15), an articulated rod, an angled rod or a drill bit or a combination thereof.

10. Installation (8) for carrying out an excavation in a ground (S) along a predetermined trajectory (X), the installation comprising a drilling device (10) comprising: a drilling tube (12) having a distal end portion (12b) which is provided with a trajectory correction head (14); a device for rotating (16) the drilling tube; a device for vibrating (18) the drilling tube configured to vibrate the trajectory correction head, the installation further comprising: - a control device (26) configured to control the rotation of the drilling tube by means of the rotation device in order to carry out drilling; - a measuring device (20) for determining a deviation of the drilling tube with respect to said predetermined trajectory and for determining, if said deviation exceeds a predetermined deviation threshold, a corrected trajectory (X”) for the drilling tube from said determined deviation and for determining an angular correction position of the trajectory correction head from said determined corrected trajectory, the control device being further configured to place said trajectory correction head in said angular correction position and to control the vibration of the trajectory correction head using the vibration device, so as to move the trajectory correction head along the corrected trajectory.

11. Installation according to claim 10, in which the control device (26) is configured to control at least once the interruption of the rotation of the drilling tube (12) during drilling, before determining the deviation of the drilling tube with respect to said predetermined trajectory (X) and in which the control device is configured to control again the rotation of the drilling tube so as to push said drilling tube into the ground according to said corrected trajectory, after having moved the trajectory correction head (14) according to the corrected trajectory (X”).

12. An installation according to claim 10 or 11, wherein the distal end portion (12b) of the drill pipe (12) is further provided with a cutting tool (13), the trajectory correction head projecting radially from the cutting tool.

13. Installation according to claim 12, in which the trajectory correction head (14) is fixed relative to the cutting tool.

14. An installation according to any one of claims 10 to 13, wherein the trajectory correction head (14) is removably mounted to said distal end portion (12b) of the drill pipe (12).

15. An installation according to any one of claims 10 to 14, wherein the drill pipe (12) has a proximal end portion (12a) and wherein the vibration device comprises a vibration generator connected to said proximal end portion of the drill pipe, the trajectory correction head (14) being vibrated by vibrating the drill pipe by means of the vibration generator.

16. Installation according to any one of claims 10 to 15, in which the drilling tube (12) extends in a longitudinal direction (Y) and in which, considered with respect to a longitudinal plane comprising said longitudinal direction, the trajectory correction head is asymmetrical.

17. An installation according to claim 16, wherein the trajectory correction head (14) comprises a beveled tool, a paddle tool (15), an articulated rod, a bent rod or a drill bit or a combination thereof.

18. Installation according to any one of claims 10 to 17, in which the measuring device (20) comprises at least one measuring member (22) chosen from: a magnetic probe, a gyrometer, an accelerometer, an inclinometer, an odometer or a combination of these.

19. Installation according to claim 18, in which the trajectory correction head (14) or the drilling tube (12) comprises the measuring member (22).

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