EP1300543A1 - Underreamer drilling system - Google Patents

Abstract

The drill pipe (3) is enclosed by a hollow outer pipe (3) and the ring-shaped cavity in between the two pipes is used to remove the drive medium from the borehole. <??>The drilling device comprises a drill head (6) with a drill bit (12), a percussion piston (14) driven by a medium in order to strike the drill bit, and a hollow drill pipe secured to the drill bit. An Independent claim is also included for an underreaming method using this drilling device.

Description

The invention relates to a drilling device for expanding an earth hole. The drilling device includes a drill head that holds a drill bit has, a percussion piston, which is driven by a drive medium and hits the drill bit, as well as a hollow drill pipe which the drill head is attached and through the cavity of the drive medium is led to the percussion piston.

The invention further relates to a method for expanding an existing one Borehole where a drill head is inserted into the borehole hollow drill pipe is attached and pulled through the borehole, being on a drill bit of the drill head during drilling Percussion piston that is driven by a drive medium, which is fed through the hollow drill pipe.

Such a drilling device, which works according to the method mentioned, is described in American patent US 5,791,419. This one described drilling device is used to drill an existing Pipe in the ground and to replace this pipe with a new pipe. The Hollow drill pipe is first pushed through the pipe to be drilled. If it emerges at the end of the pipe to be drilled, the Drill head attached to the hollow drill pipe. The drill bit, i.e. the surface of the drill head with the cutting edges or teeth, which the Removal of the material to be drilled is directed towards the drill pipe. On Percussion piston within the drill head, which is annular and surrounding the drill string can strike the back of a drill bit, who carries the drill bit. The drill bit is over a damping element axially movably attached to the drill head.

The drive medium for actuating the percussion piston - usually Compressed air - becomes the drill head through the interior of the hollow drill pipe and headed to the percussion piston. After flowing through the channels in the Drilling head and driving the percussion piston flows the drive medium through a channel to the drill bit bit. From here it can be in the pipe to be renovated parallel to the drill pipe Flow through the opening of the pipe to be drilled.

This backflow of the drive medium, which if necessary Blows drilling material out of the borehole takes place in the annulus around the Drill pipe, which with a large radial distance to the to be renewed Pipe is guided. To drill the tube essentially parallel to effect its axis, this drill head must have a guide body and have centering body. If the drill pipe is through a clogged or an area of water to be renewed Pipe is guided, there is a risk that the backflow of the drive medium is hindered or interrupted.

The object of the invention is to provide a method and an apparatus for the Extension drilling of the type mentioned in such a way that the undisturbed blowing out of the drive medium is ensured.

This object is achieved with respect to the drilling device in that the Drill pipe is surrounded by a hollow outer pipe, which one encloses the annulus surrounding the drill pipe through which the drive medium is led out of the borehole.

According to the device according to the invention, an annular second channel within a linkage designed as a double linkage created a channel separate from the environment in the borehole the drive medium fed into the borehole after driving the Percussion piston can flow through to lead out of the borehole to become. In this way, materials can be prevented from the soil surrounding the boom together with the drive medium be flushed out of the borehole. For example, if the hole runs below the water table, is through the outer drill pipe, through which the drive medium flows back, the amount of Water is reduced, which together with the drive medium from the borehole is blown out.

The method according to the invention is preferably used to extend a Pilot drilling used, which is produced in the directional drilling process has been. Directional drilling is done behind a steerable directional drilling head usually a support tube is drawn into the borehole. simultaneously a support medium is supplied, which usually consists of water offset bentonite. The support tube, which at Drilling a pilot hole with the directional drill head retracted is, preferably as an outer rod of the extension drilling device used. This support tube is flush with the borehole. The aqueous bentonite, which surrounds the support tube, has a gelatinous Consistency on the axial movement of the support tube with very little Allows frictional resistance. However, it closes an annulus outside the linkage through which the drive medium could flow out. Through the outer linkage of the drilling device according to the invention avoided that undesirably by the drive medium for the Percussion hammer the support medium is blown out of the borehole. The The drive medium can flow freely through the annulus together with the drilling material between the inner drill pipe and the outer pipe at the end of the Flow down the borehole.

Because, unlike conventional drilling methods, the drill pipe is used for extension drilling exerts a tensile force on the drill head, extends through the drill pipe preferably the drill head and is connected to the back. The percussion piston is preferably annular, that surrounds it Drill pipe and strikes the back of the drill bit of the drill head.

The drill bit, i.e. is the area that causes the soil to be removed on the side of the drill head facing away from the end of the drill pipe arranged.

The drive medium is thus through the inner drill pipe, which extends through the drill head. At the end of the inner drill pipe is screwed on a cover that the inside of the drill pipe seals and the tensile force from the drill pipe in the Initiates drilling head. The drill head has a substantially cylindrical jacket Shape. A sleeve-shaped piston is displaceable in the drill head guided. Also run in the drill head and in the sealing cover Channels for the passage of the drive medium in the ring area in which the percussion piston is received. The drive medium flows through preferably pneumatic control means which control the piston movement cause and for years in connection with pneumatic deep hole hammers are known. At the end of the flow path of the drive medium and at the end of the range of motion for the percussion piston is Impact surface of the drill bit. The drill bit is also from a channel protrudes for the passage of the drive medium, which in the area of Drill bit opens. Thus, the drive medium is initially by the inner drill pipe and then through the drill head to the Removal-causing surface of the drill bit. Towards the front of the The drill bit has at least one entry opening in the outer rod, through which the drive medium directed into the base of the expansion hole can pass through. The drive medium mentioned is thus due to the overpressure together with the removed material (Drilling material) into the annular space between the outer rod and the inner drill rod flow in and transported out of the borehole through this annular space.

Preferably, a rotary movement on the drill string Transfer the drill bit. Usually at least one is created 10 m, often over 100 m long borehole made up of individual rod segments composite linkage used. The inner drill pipe and the outer pipe preferably over one another engaging internal thread and external thread screwed together. Since the vibrations from the percussion piston are usually such Loosen screw connection is a rotary drive in the direction of the screw connection required to prevent unwanted screwing and loosening of the drill pipe to prevent. Of course and above all, the rotary movement increases which is transmitted via the drill pipe, the removal rate the drill bit.

The inner linkage and the outer linkage are particularly preferred attached to a common coupling element outside the borehole. On the one hand, the rotary movement is common via the coupling element transferred to the inner drill pipe and to the outer pipe. To the another is the drive medium via the coupling element inside of the inner drill pipe. The coupling element also has Outlet openings for the drive medium flowing out of the borehole on. The coupling element is preferably on a tunneling machine arranged, which has a linear drive, the tensile force on the Coupling element and via the coupling element on the inner drill pipe and transmits the outer linkage.

The torque can be exerted on the drill bit either by the inner rod alone or only from the outer linkage or from both linkages at the same time be transmitted.

As in the prior art, the drill bit with the drill bit is elastic damped against the drill pipe. This reduces the transfer of the Impact forces of the percussion piston from the drill bit to the drill pipe. Thus, the essential part of the energy of the percussion piston for the Material removal via the drill bit into the end face of the drill bit initiated. Only a small percentage is transferred to the drill pipe, so that it is not overloaded.

At the rear end of the drill head in the pulling direction there is preferably a Connecting element attached to which a support tube is attached. How already mentioned, the drilling device according to the invention is preferred for the extension drilling of directional drilling Pilot holes used. The support tube of the first expansion hole, which in many cases is the final one that has been drawn into the hole Forms useful pipe (e.g. for the intake of fresh water, cabling etc.) prevents the created hole from collapsing behind the drill head. The support tube is preferably linearly through without rotational movement the borehole is pulled through and is therefore of the rotary motion decoupled from the drill pipe.

The end face of the support tube drawn through the borehole is preferably closed via a head plate, which is part of the connecting element is. The head plate preferably has at least one Exit channel for a support medium, which through the support tube is brought into the borehole near the drill head. As a support medium is - as already mentioned - preferably mixed with water Bentonite used, which has a gel-like consistency and one has low friction resistance, so that the retraction of the support tube is facilitated.

The surface of the support tube head plate facing the drill pipe preferably has an oblique at least in the outer region of its circumference to the radial direction of the drill pipe surface extending in Direction tapered. The preferably conical surface the top plate causes the supporting fluid to be displaced into the peripheral Areas of the support tube.

As mentioned above, the new drilling device can be an inventive one Methods for widening an existing borehole are implemented, where a drill head is hollow on a hole drilled into the borehole Drill pipe attached and pulled through the borehole, taking on a drill bit of the drill head while drilling a percussion piston strikes, which is driven by a drive medium which by the hollow drill pipe is fed.

According to the invention and to achieve the above object together with the drill pipe an outer pipe surrounding it pulled through the borehole, between the outer rod and the Drill pipe is enclosed in an annulus through which the drive medium is led out of the borehole.

The method according to the invention is particularly preferred for expansion used by pilot holes that are produced using the directional drilling method were. The directional drilling process becomes a steerable directional drilling head driven through the earth. The directional drill head is designed that it creates a borehole, the longitudinal axis of which in a certain direction is curved. By turning the directional drilling head, the Direction of curvature can be varied. Should be drilled straight ahead the directional drilling head is continuously rotated around its longitudinal axis, so that the curvature of the borehole is even in all directions distributed and thus canceled. A directional drill head is installed according to the status technology with a directional drill pipe pushed through the borehole, wherein a support medium is introduced into the borehole, which is flush against the directional drill pipe. This directional drill pipe forms the outer linkage after completion of the pilot drilling for the drilling device according to the invention.

According to a previously unpublished European patent application by Applicants with registration number 01 201 167.2 can contact Directional drilling with one inserted in the directional drill pipe Impact drill rods Transfer impact forces to the directional drilling head become. This blow rod is, of course, before insertion of the inner drill pipe from the outer pipe. The Percussion linkage according to the European patent application mentioned exists from mutually abutting rod segments that are not together are screwed. The rod segments can, for example, by a End of the outer rod can be driven out by the a compressed air source is connected to the other end of the outer linkage.

As mentioned, is preferably on the opposite of the drill string Side of the drill head attached a support tube, which together with the drill head is pulled through the enlarged borehole. Because of this Support pipe can the above-mentioned support medium passed into the borehole become.

As mentioned, the drilling capacity is preferably achieved by using a rotary actuator coupled to the drill head increased. Here is the support tube preferably decoupled from the rotary movement of the drill pipe.

Fig. 1

eine schematische Darstellung einer Vorrichtung zur Durchführung des Richtungsbohrens,

Fig. 2

eine der Fig. 1 entsprechende schematische Darstellung einer Vorrichtung zur Durchführung einer Erweiterungsbohrung mit einem erfindungsgemäßen Bohrkopf,

Fig. 3

eine vergrößerte Darstellung des erfindungsgemäßen Bohrkopfes im Bohrloch in geschnittener Darstellung,

Fig. 4

eine Darstellung des Bohrkopfes aus Fig. 3, wobei die Fließrichtung der verschiedenen Medien dargestellt ist,

Fig. 5

eine vergrößerte Darstellung des in Zugrichtung hinteren Endes des Bohrkopfes aus den Fig. 3 und 4.

An exemplary embodiment of the drilling device according to the invention is explained below with reference to the accompanying drawings. The drawings show in:

Fig. 1

1 shows a schematic representation of a device for performing directional drilling,

Fig. 2

1 shows a schematic representation of a device for carrying out an extension bore with a drill head according to the invention,

Fig. 3

2 shows an enlarged illustration of the drill head according to the invention in the borehole in a sectional illustration,

Fig. 4

3 shows the drilling head from FIG. 3, the direction of flow of the different media being shown,

Fig. 5

an enlarged view of the rear end of the drill head in FIGS. 3 and 4.

The mode of operation of directional drilling can be seen in FIG. 1. With A tunneling machine 1 is used to create a pilot hole Direction drill head 2 by means of a directional drill pipe 3 in one Angle driven into the ground. The directional drill pipe 3 is on a rail-guided carriage of the tunneling machine 1 and is driven into the ground with a linear drive. After one Propulsion by a certain distance is applied to the directional drill pipe 3 a new section of the directional drill pipe 3 is added and the Carriage retracted to extend directional drill pipe 3 to advance further.

In the vicinity of the directional drilling head 2 is usually a magnetic one Probe 4 arranged, which allows a navigation system and a Monitor unit each the exact position of the directional drilling head 2 determine. The tunneling machine 1 also has a rotary drive 7, with which the directional drill pipe 3 rotated about its longitudinal axis and in a certain angular position can be locked. In this way can change the plane of the radius of curvature of the hole created in any Directions are inclined. The pilot hole can thus largely parallel to the surface of the earth in any direction. In particular can - as can be seen in Fig. 1 - with a large bore Radius of curvature from an entry opening into the ground to one Exit opening are guided so that obstacles without an open shoring how buildings, bodies of water or traffic areas are overcome can. If straight borehole sections are to be realized, the Direction drilling head 2 rotated evenly around its axis.

A pumping and mixing unit 5 for a rinsing medium, also support liquid called, which consists of a mixture of bentonite and water connected to the directional drill pipe 3. The support fluid will passed under high pressure in the directional drill pipe 3 and exits Rinsing nozzles in the directional drilling head 2. This will remove the material effected in the area of the directional drilling head 2. The bentonite in the Support fluid then lies in the annular gap between the Directional drill pipe 3 and the borehole. This will on the one hand produced borehole and on the other hand a fairly low-friction sliding film generates the resistance to propulsion of the directional drill pipe 3 reduced.

The major part of the material removal during directional drilling is exiting from the flushing nozzles of the directional drilling head 2 Flushing medium causes. In hard rock in particular, material is removed by impact forces exerted on the directional drilling head 2 and, if necessary, continuous rapid rotational movements increased. A directional boring head 2 with integrated hammer is, for example, from the Document DE 199 46 587 A1 known. The above unpublished European patent application with the application number 01 201 167.2 shows a directional drill head 2 in which the directional drill pipe 3 is hollow and a blow rod leads over which blows from an outside Impact mechanism can be transferred to the directional drilling head 2.

After completion of the pilot drilling, the directional drilling head 2, which has emerged from the exit opening of the bore from the directional drill pipe 3 removed. An extension drill head according to the invention can then be used 6 - hereinafter only called the drill head - on the hollow Directional drill pipe 3 according to the aforementioned European patent application attached, which is then through the pilot hole is pulled through. The linear drive is used for the tunneling machine to apply the tensile forces. Furthermore, the rotary drive 7 is used to to transmit a rotary movement to the drill head 6. At the end of the outer string 3 formed by the directional drill pipe near the Extension drill head 6 is still sensor 4 for position determination arranged. In the outer rod 3 is an inner drill pipe 8 inserted, through which on the one hand the rotational forces on the drill head 6 transmitted and on the other hand a drive medium 9 (see FIG. 4) Drill head 6 is passed. The drive medium 9 is usually compressed air, but can also consist of other suitable flowable media.

A support tube 10 is connected to the free end of the drawn drilling head 6, which during the production of the extension bore the drill head 6 is drawn into the resulting borehole. Doing so a support medium 11 for producing the extension bore (cf. FIG. 3 and 4) introduced into the support tube 10. This is why it is in the making the extension bore, the pumping and mixing unit 5 for the Support medium 11 arranged near the location where the support tube 10 from the Borehole emerges.

3 shows the drill head 6 located in the borehole in an enlarged view Presentation. The drill head 6 comprises a drill bit 12 on its the drill pipe 8 facing end. Since the drill head 6 with the drill bit 12 by means of the drill pipe 8 through the borehole into a through an arrow shown in the direction X is pulled, is in the direction of pull X facing free end face of the drill bit 12, the drill bit 13, which the Material removal in the bottom of the borehole causes.

Through the inner drill pipe 8, which the drill bit 6 to his Extends through the rear end, a drive medium 9 is passed, which drives a percussion piston 14 on the opposite of the drill bit 13 lying back of the drill bit 12 strikes. At the end of the drill pipe 8, a cover 15 is screwed on, the drill string 8th closes and transmits the tensile forces to the drill bit 13. On the Closure cover 15 is screwed on the outside of a connecting sleeve 16, the at its front end in the pulling direction X, an elastic damping element 17 wears. Against this damping element 17 is based on Intermediate piece 18 from the drill bit 12. The drill bit 12 itself is opposite the drill pipe 8 and preferably also the intermediate piece 18 held a certain distance in the axial direction. Consequently the strokes of the percussion piston 14, which are within the intermediate piece 18 of the drill head is arranged and surrounds the drill pipe 8, only introduced into the drill bit 13 and not into the drill pipe 8.

For driving the percussion piston 14 are in the cover 15th Flow channels 19 arranged which the passage of the drive medium 9 through further flow channels 20, 21 of the drill head 6 through allows in the annular space 22 in which the percussion piston 14 is guided. The pneumatic control of the percussion piston 14 of a downhole hammer is the Well known to a person skilled in the art and is not described in more detail here.

The drive medium 9 used for driving the percussion piston 14 flows through a plurality of flow channels 23 in the drill bit 12 to the latter in the pulling direction X front end face, which forms the drill bit 13. The Drive medium 9 has an overpressure compared to the atmosphere, so that it is from the area in front of the drill bit 13 together with the drill material 24 enters an annular inlet opening 25, which between the inner drill pipe 8 and the outer pipe 3 at a distance from Drill bit 13 is arranged. The drive medium 9 can then together with the cuttings 24 through the annular space between the drill pipe 8 and outer linkage 3 flow until it through outlet openings 26 on End of the outer rod 3 emerges outside the borehole.

The outlet openings 26 are on a common coupling element 27 arranged, which both the inner drill pipe 8 and the outer pipe 3 wears. Via a ring seal 28 is a feed line 29 for the drive medium 9 connected to the coupling element 27. inlet channels 30, which open into the ring seal 28, make this possible Inflow of the drive medium 9 into the interior of the inner drill pipe 8th.

The coupling element 27 is with the rotary drive 7 and the linear drive the tunneling machine 1 (see. Fig. 2) connected and transmits the train and Rotational forces on the inner drill pipe 8 and the outer pipe 3.

It can thus be seen that the design of the invention Drilling device to remove the drive medium from the borehole through the double-walled linkage is possible without an outflow Require outside the drill pipe through the borehole itself. This is particularly true in the case of the directional drilling described important, because - as described below - the walls of the hole over one Support medium are supported, which is not by the drive medium 9 may be blown out. Because the channel for blowing out the drive medium is realized in the linkage of the drilling device, that can Place the rods flush against the borehole to be expanded. So must the drill head 6 is not centered within the borehole to be expanded or be performed.

As mentioned, the enlarged bore is preferably shared by one support tube 10 pulled through the borehole with the drill head 6 lined. For this reason, the cap 15 is at the end of the drill pipe 8, a pull bell 31 fixedly connected via a roller bearing 32 is decoupled from the rotary movement of the drill head 6. About one Pull element 32, a head plate 33 is connected to the pull bell 31. On the head plate 33 is the support tube 10 z. B. via a threaded connection attached.

The support liquid 11 (consisting of a Bentonite / water mixture) into the borehole. The head plate 33 has a plurality of outflow channels 34 for the support liquid 11. The in the direction of pull X front surface of the head plate 33, which towards the bell 31 has a conical shape in order to displace the support liquid 11 in the area in front of the head plate 33 towards the wall of the borehole favor. So a lightly compacted bentonite layer between the Wall of the support tube 10 and the soil created, which due their gel-like consistency the friction between the support tube 10 and the ground reduced.

LIST OF REFERENCE NUMBERS

1

boring machine

2

Directional drilling head

3

Directional drill pipe, outer pipe

4

magnetic probe

5

Pump and mixing unit

6

wellhead

7

rotary drive

8th

inner drill pipe

9

drive medium

10

support tube

11

support medium

12

drill bit

13

drill bit

14

percussion piston

15

cap

16

connecting sleeve

17

damping element

18

connecting piece

19

flow channel

20

flow channel

21

flow channel

22

annulus

23

flow channel

24

cuttings

25

inlet opening

26

outlet opening

27

coupling member

28

ring seal

29

supply line

30

inlet channel

31

Zugglocke

32

tension element

33

headstock

34

outflow

X

tensile direction

Claims (24)

Drilling device for expanding an earth hole, with a drill head (6) which has a drill bit (12), an impact piston (14) which is driven by a drive medium (9) and strikes the drill bit (12), a hollow drill pipe (8) to which the drill head (6) is attached and through the cavity of which the drive medium (9) is guided to the percussion piston (14), characterized in that
the drill pipe (8) is surrounded by a hollow outer pipe (3) which encloses an annular space surrounding the drill pipe (8) through which the drive medium (9) is led out of the borehole. Drilling device according to claim 1, characterized in that the drill rod (8) extends through the drill head (6). Drilling device according to claim 1 or 2, characterized in that the percussion piston (14) is annular and is penetrated by the drill rod (8). Drilling device according to one of the preceding claims, characterized in that a drill bit (13) is arranged on the side of the drill head (6) facing away from the end of the drill rod (8). Drilling device according to claim 4, characterized in that the outer rod (3) near the drill bit (13) has at least one entry opening (25) for the entry of the drive medium (9), possibly together with the drill material (24). Drilling device according to one of the preceding claims, characterized in that at least one outlet opening for the drive medium (9) is arranged in the drill bit (13). Drilling device according to one of the preceding claims, characterized in that the drill bit (13) is non-rotatably connected to the drill rod (8) and that the drill rod (8) is connected non-rotatably to a rotary drive (7) outside the borehole. Drilling device according to one of the preceding claims, characterized in that the drill bit (13) is connected in a rotationally fixed manner to the outer linkage (3) and in that the outer linkage (3) is connected in a rotationally fixed manner outside the borehole to a rotary drive (7). Drilling device according to one of the preceding claims, characterized in that the drill pipe (8) is connected outside the borehole with a linear drive which pulls the drill pipe (8) through the borehole. Drilling device according to one of the preceding claims, characterized in that the drill bit (13) is movably connected to the drill rod (8) in the axial direction via an elastic damping element (17). Drilling device according to one of the preceding claims, characterized in that a connecting element (31, 32, 33) to which a support tube (10) is attached is attached to the end of the drill pipe (8) located in the borehole. Drilling device according to claim 11, characterized in that the support tube (10) is decoupled from the rotary movement of the drill rod (8). Drilling device according to claim 11 or 12, characterized in that the connecting element has a head plate (33) for closing the support tube (10). Drilling device according to claim 13, characterized in that the head plate (33) has at least one outflow channel (24) for a support medium (11) fed through the support tube (10). Drilling device according to claim 13, characterized in that the surface of the head plate (33) facing the drill rod (8) extends obliquely to the radial direction of the drill rod (8) at least in the outer region of its circumference. Method for expanding an existing borehole, in which a drill head (6) is attached to a hollow drill pipe (8) inserted into the borehole and is pulled through the borehole, whereby a drill bit (12) of the drill head (6) is engaged during drilling Percussion piston (14) which is driven by a drive medium (9) which is fed through the hollow drill pipe (8),
characterized in that, together with the drill pipe (8), an outer pipe (3) surrounding it is pulled through the borehole, an annular space being enclosed between the outer pipe (3) and the drill pipe (8), and in that the drive medium (9) this annular space is led out of the borehole. A method according to claim 16, characterized in that the outer rod (3) is introduced into the borehole in such a way that it lies flush against the wall of the borehole. A method according to claim 17, characterized in that a steerable directional drilling head (2) is attached to the end of the outer rod (3) in the borehole. A method according to claim 17, characterized in that when the outer rod (3) is introduced, a support medium is introduced into the borehole produced by the directional drilling head (2), which forms a borehole wall lying flush against the outer rod (3). A method according to claim 17 or 18, characterized in that during drilling with the directional drill head (2) a percussion rod extending within the outer rod (3) transmits blows to the directional drill head (2) and that before the inner drill rod (2) is inserted 8) the blow rod is driven out of the outer rod (3). Drilling device according to one of claims 16 to 19, characterized in that a support tube (10) is fastened to the side of the drill head (6) opposite the drill pipe (8), which is pulled through the enlarged borehole together with the drill head (6). A method according to claim 21, characterized in that a support medium (11) is passed through the support tube (10) into the borehole and emerges at the end of the support tube (10) near the drill head (6). Method according to one of claims 16 to 22, characterized in that the drill head (6) is set in rotation by means of a rotary drive (7) over at least one of the rods (3, 8). Method according to claims 21 and 23, characterized in that the support tube (10) is decoupled from the rotary movement of the linkage (3, 8).

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