EP2497896A1 - Tool, facility and method for making horizontal boreholes - Google Patents

Abstract

The tool (14) has an upstream face (15) comprising a connection unit that is formed of a threaded end fitting (17) to connect the upstream face to a rotary guiding head (21), and an arm comprising a proximal part fixed with respect to a rotational axis (13). The guiding head comprises a proximal end and a distal end, and is provided with a conical thread coupled with the threaded end fitting. The arm comprises a distal part that is pivotably mounted on the proximal part. The upstream face is arranged with respect to a working direction of the tool. Independent claims are also included for the following: (1) a horizontal drilling installation (2) a horizontal drilling method.

Description

The present invention relates to a drilling tool, for horizontal drilling, facilities incorporating such a tool and drilling methods using these facilities.

There are different techniques for making horizontal drilling, for example for the installation of pipes or cables, without opening trenches in the ground over the entire length to receive the pipe or cable.

One of these techniques is horizontal directional drilling which includes, from an entrance to the natural surface of the soil, the creation of a pilot hole of small diameter (≤ 250 mm) using a horizontal drill rig a train of rods driven to emerge at an exit, for example a pit, after having rounded any obstacles. The term "horizontal" is used here as opposed to vertical drilling although the direction of penetration into the soil includes a vertical component. The drill string in question has a proximal end mounted on the horizontal drill directed, proximal here being understood as the downstream side according to the direction of drilling or the direction of progression. The drill string further comprises a distal end, distal here being understood as the upstream side, provided with a tool which, in the orientation given to it, by control and control means known per se, digs horizontally sinks into the ground, rises to the surface, obliquely to the right or to the left, or operates any combination of these movements.

Once the pilot hole is created, the tool mounted at the distal end of the rod is disassembled and replaced with a boring tool. The pilot hole is then reamed by the return, to the horizontal drilling machine, of the rod thus equipped. The reamer is disassembled, the rod is reintroduced into the hole until re-emerge in the pit and a new, larger, reamer is mounted at the distal end of the stem. A series of round trips with increasing each time the size of the reamer makes it possible to enlarge the hole until obtaining a tunnel having up to 1.5 times the diameter of the pipe to put in place. At this point, the rod is reintroduced into the hole to re-emerge, once again, in the pit, and the last reamer is raised on the distal end of the rod, then joined to said pre-assembled pipe that we want to put in place. This meeting is done with the interposition of a part allowing the rotation of the rod and the reamer, without rotation of the pipe. The pipe is then drawn from the borehole outlet to the horizontal directional drill.

• ■ faciliter la pénétration des outils dans le sol,
• ■ refroidir ces outils, et
• ■ transporter les "cuttings" (terres ou morceaux de roches broyées) hors du tunnel foré soit vers le trou d'entrée, soit vers le trou de sortie du forage.

This technique, which accepts large slope variations (from -15 ° to + 15 °), uses water-based sludge and bentonite sludge for:

• ■ facilitate the penetration of tools into the soil,
• ■ cool these tools, and
• ■ transport the cuttings out of the drilled tunnel either to the inlet hole or to the borehole exit hole.

• ■ du forage tarières
• ■ du forage par micro-tunnelier
• ■ du forage par pousse-tubes.

Other horizontal drilling techniques do not operate from the natural surface of the soil but require the creation of a pit at the entrance and exit of the borehole. It's about :

• ■ auger drilling
• ■ micro-tunneling drilling
• ■ tube-hole drilling.

The auger drilling penetrates into the ground a steel sheath formed of a train of tubes each of which houses an auger, the most upstream auger, that is to say the farthest from the entrance, following a drill head that digs the ground. This drilling head may take the form of arm radiating from an axis of rotation, or the shape of a helix. The tube train and augers advance together under the effect of a thrust exerted on the most downstream tube. The augers, set in rotation by the drill, bring the cuttings back to the pit of the drilling, via the set of tubes in place.

Such drilling can only be practically horizontal and it is carried out dry, that is to say without drilling muds.

Micro-tunneling drilling uses, instead of a drill head, a cutting wheel equipped with knives for soft terrain or wheels for rocky terrain.

The trajectory of such drilling is usually horizontal. It is virtually straight for drill diameters less than 1000 mm. Beyond this, it can be given a slight curve (radius of curvature> 500 m) by acting on directional cylinders directing the micro-tunneling cutter wheel.

The cuttings pass through the cutting wheel and are evacuated and transported by hydraulic picking, that is to say by circulating a closed loop of drilling mud in pipes.

Pipe drilling is limited to forcing tubes into the soil. It can only be used for short distances and is necessarily straight and non-steerable. This technique is very destructive for the surrounding basement.

The performances of the techniques recalled above are summarized in the table below: directed drilling drilling augers micromachining tube drill maximum length of drilling 2500 m about 100 m 2000 m 80 m maximum diameter of the tubes in place 1500 mm 1500 mm 4 m 3 m guiding capacity very good and on 3 axes weak and 2 axes weak but on 3 axes nothing technical incompatibilities presence of coarse gravel and pebbles in the basement presence of water in the basement sands engorged with water or non-bearing land presence of large pebbles or rocks. need for a departure pit and an arrival pit no Yes Yes Yes advantage (s) of this technique very good guidance speed and moderate cost without competition beyond a diameter of 3 m speed and moderate cost

The present invention aims to provide a new drilling technique that combines the advantages of horizontal directional drilling (very good guidance and no need to dig a pit at both ends of the borehole) the advantages of other techniques (possibility to work in soils containing coarse gravel and pebbles and, in some cases, without the use of transporting cuttings by drilling muds).

This objective is achieved in that the invention provides a drilling tool having an upstream face, with reference to the working direction of said tool, and an opposite downstream face, characterized in that said upstream face comprises connecting means to a rotary driving guide rod.

This guide rod is rotated by a horizontal drill directed.

In a first embodiment, the tool according to the invention takes the form of an auger drill bit.

In a second embodiment, the tool according to the invention takes the form of a cutting wheel of a micro-tunneler.

Naturally, the direction of rotation of the guide rod and that of the tool must be the same.

• d'allonger les forages horizontaux, par rapport aux forages à tarières, grâce au gain de couple et de puissance assuré par les deux foreuses (foreuse dirigée/foreuse à tarières ou foreuse dirigée/micro-tunnelier) qui fonctionnent simultanément avec des rotations synchronisées, et
• de diriger ces forages, par rapport aux forages à tarières et par micro-tunnelier, grâce à la réalisation préalable d'un trou pilote dirigé, alésé, qui permet ensuite le guidage de l'outil de forage tarières ou la roue de coupe du micro-tunnelier.

Whether the tool is a drill head of an auger or a cutting wheel of a micromachiner, its connection, via the guide rod, with a horizontal drilling machine allows:

• to lengthen the horizontal drilling, compared to the auger drilling, thanks to the gain of torque and power provided by the two drills (controlled drill / auger drill or directed drill / micro tunneler) which operate simultaneously with synchronized rotations, and
• directing these boreholes, compared to auger drilling and micro tunneling, thanks to the preliminary realization of a pilot bore, reamed, which then allows the guidance of the auger drilling tool or the cutting wheel of the micro -tunnelier.

The connection means of the drilling tool according to the invention are advantageously constituted by a threaded end and said guide rod is provided at its distal end with a thread matched to said threaded end.

Said tip can offer a female thread and the rod a male thread, or vice versa. These are preferably conical threads for sealing, alignment and quick assembly.

When the drilling tool according to the invention is a drill head of an auger drill, it is advantageously mounted upstream of at least two tubes each containing an auger, the most upstream tube having an annular shoulder forming an abutment. for a cylindrical flange mounted in pivot connection on the axis of rotation of the augers.

This arrangement helps to advance the tubes. Indeed, the thrust force is transmitted to the auger by the pivot connection and the flange which bears on the shoulder of the tube.

When drilling augers in a rocky terrain, it is important that the cutting tool clear the passage upstream of the tube that follows and, therefore, this tool must be of a larger diameter than said tube . On the other hand, the tool must it can be extracted via said tube, to change its abrasive parts or at the end of work.

In order to meet these contradictory requirements, the invention proposes to use, in this case, a tool which comprises arms provided with abrasive parts (of the type with steel or carbide pins) and radiating from an axis of rotation, said arm comprising a proximal portion and a distal portion, relative to said axis of rotation, said proximal portion being fixed relative to said axis and said distal portion being pivotally mounted on the proximal portion, said arms being capable of passing from a retracted configuration into which tool has a first diameter smaller than that of said tube and an extended position in which the tool has a second diameter greater than the diameter of said tube.

In a preferred embodiment, the tool according to the invention incorporates a distribution duct system for introducing a drilling fluid for ejection out of the tool.

This ejection will be lateral in the case of an auger drill bit, and lateral and frontal in the case of a micro-tunneling cutter wheel. When the tool according to the invention is used as a drilling head of a drill auger, the ejected fluid serves only to facilitate the sliding of the tube, not to evacuate the cuttings, except in the particular case of drilling lands rocky. On the other hand, if the tool according to the invention is used as a cutting wheel of a micro-tunneling machine, the ejected fluid will participate in hydraulic pickling.

As indicated above, the present invention relates to a drilling tool.

It also concerns installations incorporating it.

Thus, according to a first aspect, the invention relates to an installation for horizontal drilling, comprising an auger and a horizontal drilling rig, the auger drill using as a drilling head the tool according to the invention. The guide rod, or the train of guide rods to which it belongs, is rotatably mounted / rotatably mounted by its proximal end on the horizontal auger directed and the latter being adapted to rotate the guide rod, or the drill string in the same direction as the drill head.

According to a second aspect, the invention relates to a horizontal drilling installation, comprising a micro-tunneling machine and a directed horizontal drilling machine, the micro-tunneling machine using the tool according to the invention as a cutting wheel. Said guide rod, or the train of guide rods to which it belongs, is mounted / rotatably mounted / rotated by its proximal end on the horizontal auger directed and the latter being adapted to rotate the guide rod, or the drill string in the same direction as the cutting wheel.

• la tige de guidage, ou le train de tiges de guidage,
• ledit outil, et
• une ou plusieurs tarières logées dans le ou les tubes poussés, lesquelles tarières sont connectées à l'outil et ont pour fonction de repousser les terres hors du ou des tubes poussés.

According to a third aspect, the invention relates to a horizontal drilling installation, comprising a pipe-driver and a directed horizontal drilling machine, the pipe-driver being equipped with the tool according to the invention, said guide rod, or the train. of guide rods to which it belongs, being rotatably mounted / rotatably mounted by its proximal end on the horizontal auger directed and the latter being adapted to rotate

• the guide rod, or the set of guide rods,
• said tool, and
• one or more augers housed in the pushed tube or tubes, which augers are connected to the tool and have the function of pushing the lands out of the tube or tubes pushed.

It will be understood, according to this third aspect, that the invention transforms the technique of the tube pusher which, conventionally, is devoid of rotary means of ground attack and evacuation of the cuttings, by equipping it with such a rotary means in this case the tool according to the invention rotated by the horizontal drill directed and transmitting itself this movement auger.

• du forage dirigé qui comprend, depuis une entrée à la surface du sol

la création d'un trou pilote à l'aide d'une foreuse horizontale dirigée munie d'une tige pilotée pour émerger au niveau d'une sortie après avoir contourné d'éventuels obstacles, puis,
après avoir équipé l'extrémité de ladite tige d'un outil d'alésage, l'alésage du trou pilote par le rappel de la tige ainsi équipée vers la foreuse horizontale dirigée, et

• du forage tarière, ou du forage par micro-tunnelier, ou du forage par pousse-tubes, lesquels comprennent, depuis une fosse, l'introduction dans le sol d'un tube, ou d'un train de tubes, par poussée exercée sur ce tube ou train de tubes, tube(s) via lequel/lesquels les terres attaquées par le forage sont évacuées vers la fosse,
  caractérisé en ce que :
• ladite sortie du trou pilote se fait dans ladite fosse ;
• ledit procédé consistant, après l'alésage du trou pilote :
  • à séparer, de la foreuse dirigée, la tige de forage du trou pilote alésé, et à la remplacer par une tige de guidage, ou un train de tiges de guidage, ayant une extrémité proximale et une extrémité distale, ladite extrémité proximale étant munie d'un moyen de connexion à la foreuse horizontale dirigée et ladite extrémité distale étant munie d'un moyen de connexion à un outil de forage appartenant, respectivement, à une foreuse tarière ou à un micro-tunnelier ou venant équiper le pousse-tubes,
  • à connecter ladite extrémité distale de la tige de guidage audit outil de forage, côté amont par référence à la direction de travail dudit outil de forage,
  • à faire fonctionner la foreuse horizontale dirigée de telle sorte que la tige de guidage, ou le train de tiges de guidage, tourne(nt) dans le même sens que ledit outil de forage,
  la foreuse horizontale dirigée tirant l'outil de forage, depuis le côté amont, en le guidant tandis que le tube ou le train de tubes sont poussés, depuis le côté aval, dans la direction de travail dudit outil de forage.

The invention also relates to a horizontal drilling method using the principles

• directional drilling that includes, from an entrance to the soil surface

the creation of a pilot hole using a directed horizontal drill equipped with a driven rod to emerge at an exit after having circumvented any obstacles, then,
after having equipped the end of said rod with a boring tool, the bore of the pilot hole by the return of the rod thus fitted to the horizontal drilling machine directed, and

• auger drilling, or microbnr tunnel drilling, or pipe-drilling, which includes, from a pit, the introduction into the ground of a tube, or a string of tubes, by thrust on this tube or tube train, tube (s) via which the lands attacked by the borehole are evacuated to the pit,
  characterized in that
• said pilot hole exit is in said pit;
• said method consisting, after boring the pilot hole:
  • separating the drill stem from the reamed pilot hole from the guided drill, and replacing it with a guide rod, or a set of guide rods, having a proximal end and a distal end, said proximal end being provided with means for connection to the horizontal drilling rig and said distal end being provided with means for connecting to a drilling tool belonging, respectively, to an auger or a micro-tunneling machine or coming to equip the pipe-driver,
  • connecting said distal end of the guide rod to said drilling tool, upstream side with reference to the working direction of said drill bit,
  • operating the horizontal auger directed so that the guide rod, or the drill string, rotates in the same direction as said drill bit,
  the horizontal drilling machine pulling the drilling tool from the upstream side, guiding it while the tube or the string of tubes are pushed from the downstream side, in the working direction of said drill bit.

• la figure 1 est un schéma montrant l'organisation générale de mise en oeuvre du procédé selon l'invention ;
• la figure 2 est une vue en coupe d'une première forme d'exécution de l'outil selon l'invention dans laquelle ledit outil forme tête de forage d'une foreuse à tarières ;
• la figure 3 est un agrandissement d'une zone de la figure 2 ;
• la figure 4 montre une variante de réalisation de l'outil représenté à la figure 2 ; et
• la figure 5 est une vue en coupe d'une seconde forme d'exécution de l'outil selon l'invention dans laquelle ledit outil forme roue de coupe d'un micro-tunnelier.

The invention will be better understood on reading the following description given with reference to the appended figures in which:

• the figure 1 is a diagram showing the general organization of implementation of the method according to the invention;
• the figure 2 is a sectional view of a first embodiment of the tool according to the invention wherein said tool forms a drilling head of a drill auger;
• the figure 3 is an enlargement of an area of the figure 2 ;
• the figure 4 shows an alternative embodiment of the tool shown in FIG. figure 2 ; and
• Figure 5 is a sectional view of a second embodiment of the tool according to the invention wherein said tool forms cutting wheel of a micromachiner.

If we refer to the figure 1 , we see a section of land 1 made through a stream 2. A horizontal drill directed is schematized in 3 on the surface of the ground 4 while a pit 5 has been dug to accommodate a drill auger or a micro-tunneling machine or a pipe-lift schematized in 6.

As indicated above, the general principle of the method embodying the invention comprises (a) from an inlet 7 to the surface 4 of the ground, the creation of a pilot hole 8 using the horizontal drilling machine 3 provided with a train of rods piloted for emerge at an outlet 9 in the pit 5 bypassing the bottom of the stream 2, then (b) after having equipped the distal end of the drill string with a boring tool, the bore of the pilot hole 8 by the return of said train, thus equipped, towards the horizontal drilling machine directed 3.

After the desired number of round trips with reamers larger and larger, is separated, the drill directed 3, the drill string drill pilot hole 8 reamed, and replaced by a guide rod, or a train of guide rods. These guide rods are hollow rods of constant section, large diameter, for example 19.37 cm (7 ^5/8 inches), and thick to transmit torque up to 15 000 Nm and pulls up to 400 tonnes.

Directed horizontal drills are traditionally designed to be equipped with right-hand drills: they rotate clockwise depending on the direction of drilling. Likewise, the drill heads of the auger drills and the micro-tunnelers traditionally turn clockwise depending on the direction of drilling. So that the guide rod rotates in the same direction as the drill head of a drill auger or the cutting wheel of a micro-tunneler, while the horizontal auger and auger / micro-tunneler are oriented in opposite directions, one of the two engines turns counterclockwise. The guide rod is thus provided with a left-hand thread and an ad hoc adapter is interposed between the horizontal auger directed and the guide rod to allow connection, proximal end side of said rod.

Alternatively, the guide rod is provided with a right-hand thread in a conventional manner. The direction of rotation of the drill head of the auger / micro-tunnel boring machine is reversed (counterclockwise) compared to the traditional direction. Thus, the augers are arranged on the left. This variant reduces the consequences potential error by the operator controlling the operation of the horizontal drill.

If we come to the figure 2 which shows in detail the right end of the figure 1 applied to the case of the use of an auger driller, there is the pit 5 in which are installed the control members 6a of said auger driller. The auger drill comprises a tube train 10a, 10b, (...) and 10n and augers 11a, 11b respectively housed in the tubes 10a, 10b. The control members 6a control thrust means 12, for example cylinders, acting on the tube 10n. A tube T was forcibly introduced into the ground to provide a starting guide to the tubes 10a, then 10b, etc. It is understood that the tube 10n also contains an auger (not shown) and that, when the tubes 10a, 10b, (...) 10n have penetrated into the ground to the point that the free edge of the tube 10n is flush with the wall of the pit 5, a new tube 10m (not shown) is inserted between the thrust means 12 and the tube 10n.

The augers 11a and 11b are rotatably mounted about an axis 13 on which is also rotatably mounted, in the clockwise direction (or counterclockwise in the case of the variant described above), the cutting tool 14 according to the invention. invention, downstream side face 16 of said tool 14. As can be seen better at the figure 4 , upstream face side 15, the tool 14 comprises a nozzle 17 having a left-hand thread (right in the case of the above-mentioned variant) conical female 18 paired with a thread on the left (right in the case of the aforementioned variant) conical male 19 provided at the distal end 20 of a guide tube 21, possibly belonging to a string of tubes, whose proximal end is mounted on the horizontal drilling machine 3.

The tube 21 is hollow and its interior communicates with a drilling fluid distribution system provided in the tool 14 so that the latter can be fed with drilling fluid for lateral discharge according to the arrows F ( figure 2 ).

As is best seen in the figure 3 , there is provided on the inner face of the tube 10a an annular radial shoulder 22 forming axial abutment for a cylindrical flange 23 mounted pivotally connected to the axis 13.

The figure 4 shows an alternative embodiment of the tool according to the invention adapted to the case of an installation incorporating a drill augers to attack a rocky soil. In this figure, the common parts in the figure 2 are designated by the same references. In this case, the tool comprises arms radiating from the axis 13 and which are in two parts: a proximal portion 24a integral with the body 25 or rigid relative to the body 25 of the tool and a distal portion 24b pivotally mounted in 26 and along an axis substantially perpendicular to the axis 13, on the proximal portion 24a. A series of abrasive pieces 27 is mounted on the upstream face of each arm, only one of these abrasive parts being shown in the figure, in the vicinity of the free edge of the distal portion 24b. When the tool is in the configuration shown in the figure 4 its diameter d1 is greater than the outside diameter D1 of the tube 10a so that the abrasive piece 27 at the end of the arm disengages the passage for said tube 10a. On the other hand, when the distal portion 24b is pivoted about the axis 26, the tool has a diameter d2 smaller than the inside diameter D2 of the tube 10a, so that the tool can be extracted from the inside of the tube. tube 10a, for example to replace abrasive parts, such as 27.

Figure 5 is similar to figure 2 except that it shows an installation using a micro-TBM 6b instead of a drill auger.

In this figure, the parts identical to the figure 2 are designated by the same references and similar parts are designated by the same references followed by the prime sign.

In this case, the tool according to the invention takes the form of a cutting wheel 14 'of a diameter greater than that of the tubes 10a', 10b ', 10c', etc. and the drilling fluid distribution system is front and side ejection, according to arrows F '.

It is understood that in the present description and in the claims, the terms "tube" and "rod" refer both to an individual tube or rod (1a) as well as to a string of tubes or drill string, and conversely, the terms "tube train" or "drill string" may refer to an individual tube or rod (the).

A drilling tool, for horizontal drilling, comprises an upstream face and a downstream face with reference to the working direction of said tool. Said upstream face comprises means of connection to a rotary guide rod, driving and able to pull said tool. Said downstream face comprises connection means to a rotary shaft, motor and adapted to push said tool. In an installation comprising the tool, the guide rod is connected to a directed horizontal drill. The tree is connected to, or is part of, a drill auger or a micro-TBM.

A horizontal drilling rig includes a horizontal auger and auger or a micromachiner, with a first end of a rotating guide rod mounted to the horizontal auger, a second end of said guide rod being connected to a tool drilling to rotate and pull the drilling tool, by an upstream face of said tool, said tool belonging to the augers auger or micromachemaker rotating and pushing the drill bit, the horizontal drill the guide rod, the drilling tool and the auger or the micro-tunneling machine being mutually arranged to have a common direction of rotation.

Claims (11)

An auger or micro-tunneling auger drilling tool for horizontal drilling, said drilling tool having an upstream face (15), with reference to the working direction of said tool, and an opposite downstream face (16), characterized in that that said upstream face (15) comprises connection means (17; 19) to a guide rod (21), rotating, motor. Tool according to claim 1, characterized in that said connection means consist of a threaded end (17, 18) and that said guide rod (21) has a proximal end and a distal end (20). , is provided at its distal end with a thread (19) matched to said threaded end (17, 18). Tool according to claim 1 or 2, characterized in that it incorporates a distribution duct system for introducing a drilling fluid for ejection (F; F ') out of the tool. Tool according to any one of claims 1 to 3, which comprises arms provided with abrasive parts (27) and radiating from an axis of rotation (13), said tool (14) being mounted upstream of a tube (10a) characterized in that said arms comprise a proximal portion (24a) and a distal portion (24b), relative to said axis of rotation (13), said proximal portion (24a) being fixed relative to said axis (13) and said portion distal (24b) being pivotally mounted (26) on the proximal portion (24a), said arms being capable of passing a retracted configuration in which the tool has a first diameter (d2) smaller than the inside diameter (D2) of said tube (10a) and an extended position in which the tool has a second diameter (d1) greater than the outer diameter (D1) of said tube (10a). Tool according to one of Claims 1 to 4, characterized in that it is in the form of an auger drill bit. Tool according to claim 4 or 5, mounted upstream of at least two tubes (10a, 10b) each containing an auger (11a, 11b), the most upstream tube (10a) having an annular shoulder (22) inside forming a stop for a cylindrical flange (23) pivotally mounted on the axis of rotation (13) of the augers (11a, 11b). Tool according to any one of claims 1 to 3, characterized in that it takes the form of a cutting wheel of a micromachiner. Horizontal drilling rig, comprising an auger drill and a horizontal drilling machine (3), characterized in that the auger drilling machine uses as a drilling head (14) the tool according to any one of claims 1 to 6, said the guide rod (21), or the train of guide rods to which it belongs, being rotatably mounted / rotatably mounted by its proximal end on the horizontal drilling machine (3) and the latter being adapted to rotate the guide rod ( 21), or the drill string, in the same direction as the drill head (14). Horizontal drilling installation, comprising a micro-tunneling machine and a horizontal drilling machine, characterized in that the micro-tunneling machine uses as a cutting wheel (14 ') the tool according to any one of claims 1 to 3 or 7, said the guide rod (21), or the train of guide rods to which it belongs, being rotatably mounted / rotatably mounted by its proximal end on the horizontal drilling machine (3) and the latter being adapted to rotate the guide rod ( 21), or the drill string, in the same direction as the cutting wheel (14 '). Horizontal drilling installation, comprising a pipe driver and a directed horizontal drilling machine, characterized in that the pipe-driver is equipped with the tool according to any one of claims 1 to 4, said guide rod, or the the guide shaft to which it belongs, being rotatably mounted / mounted by its proximal end to the horizontal boring machine and the latter being adapted to rotate - the guide rod, or the train of guide rods, said tool, and - One or more augers housed in the tube or tubes pushed (s). Horizontal drilling method using the principles
directed drilling which includes from an inlet (7) to the ground surface
the creation of a pilot hole (8) using a directed horizontal drill (3) provided with a driven rod train to emerge at an outlet (9) after having circumvented any obstacles ( 2), then,
after having equipped the end of said drill string with a boring tool, the bore of the pilot hole (8) by the return of the drill string thus fitted to the horizontal drilling rig (3), and
auger drilling, or micromachining, or pipe-drilling, which includes, from a pit (5), introducing into the soil a tube, or a string of tubes (10a). , 10b), by pushing on this tube or tube train, tube (s) via which the lands attacked by the borehole are discharged to the pit (5),
characterized in that - said exit (9) of the pilot hole (8) is in said pit (5); - said method consisting, after boring the pilot hole: separating the drill string from the reamed pilot hole from the guided drill (3) and replacing it with a guide rod (21) or a set of guide rods having a proximal end and an end distal (20), said proximal end being provided with means for connection to the horizontal drill directed (3) and said distal end (20) being provided with a connection means (19) to a drilling tool (14; 14 ') belonging, respectively, to a drill auger or a micromachiner or to equip the tube driver, connecting said distal end (20) of the guide rod (21), or the drill string, to said drill bit (14; 14 '), upstream side (15) with reference to the working direction of said tool drilling, operating the horizontal auger (3) such that the guide rod, or the drill string, rotates in the same direction as said drill bit (14; 14 '), the horizontal drill directing (3) pulling the drill bit (14; 14 ') while guiding it while the tube or the string of tubes (10a, 10b) are pushed in the working direction of said drill bit.

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