EP2278115B1 - Extension for a drilling rod - Google Patents

Abstract

The bar (10) has telescopable pipe elements e.g. inner pipe element (1'), center pipe element (1'') and lower pipe element (1'''), arranged into each other in a radial direction and movable against each other in an axial direction. A level arm-connection unit connects the bar with a telescopable drill pipe (50), and a tool-connection unit connects the bar with a drilling tool. The level arm-connection unit and the tool-connection unit are arranged in the inner- and lower pipe elements, respectively. A retaining unit supports the pipe elements in a drillhole mouth. Independent claims are also included for the following: (1) a drilling device comprising a tower (2) a method for forming a drill hole.

Description

The invention relates to an extension for a drill pipe, in particular for a telescopic drill pipe, according to the preamble of claim 1, with a linkage connection means for connection of the extension with the drill pipe and a tool connection means for connecting the extension with a drilling tool.

For the production of holes in the ground with large rotary drilling rigs, for example for the production of foundation piles for buildings, it is known to use telescopic drill pipe, in particular so-called Kelly linkage. Such Kelly linkage consists of several nested Kelly tubes, the innermost Kelly tube hanging from a rope of the rotary drilling rig and thus can be moved up and down. This allows the Kelly linkage to be telescoped. At the bottom of the innermost Kelly tube, the drilling tool is attached. By vertical strips on the Kelly tubes or corresponding drive grooves on each adjacent Kelly tube, the torque and thus the rotational movement is transmitted from one Kelly tube to another similar to a shaft-hub connection. In this way, the rotational movement of the rotary drive, which acts on the outermost drill pipe, to the drilling tool, which is arranged on the innermost Kelly tube, transmitted. Such Kellygestänge are for example from the EP 1 445 418 A1 known.

The achievable with a conventional Kelly linkage maximum drilling depth is determined by the length of the extended drill pipe. This length again corresponds approximately to the length of the retracted drill string multiplied by the number of individual Kelly tubes. However, these two latter parameters are not freely variable in practice, so that the maximum drilling depth is not arbitrary can be increased. In particular, on the one hand, the maximum deployable retracted rod length is usually limited by the height of the equipment tower and the required free height above ground (ground level). On the other hand, the number of individual Kelly tubes is limited by the diameter of the hollow shaft in the rotary drive, since in general all Kelly tubes must be passed through this hollow shaft. Although is out of the DE 40 38 424 C1 known to lead the outermost Kelly tube only below the rotary drive, instead of this to perform through the hollow shaft. But even with such an arrangement, the number of individual Kelly tubes is ultimately limited by geometric specifications, so that there is limited to the maximum extended rod length accordingly.

If drilling is required deeper than the length of the extended linkage length, an extension rod can be attached to the Kelly drill pipe. By such Kellygestängeverlängerung the maximum achievable depth can be increased. However, the maximum achievable with such Kellygestängeverlängerung drilling depth increase is limited by the fact that the entirety consisting of extension rod and drilling tool must be shorter than the free height between Planum and retracted Kellygestänge, because only then the drilling tool can be swung out to empty out of the hole. Typically, a drilling depth increase of a maximum of 3 to 5 m can thus be achieved with an extension rod.

For even greater drilling depths, it could be considered to mount or dismount several extension rods with a hoist above the borehole. However, then a complete assembly and subsequent disassembly of the extension rods for emptying the drilling tool is necessary for each drilling game, which would be relatively time consuming. The drilling performance would be only comparatively low.

From the DE 198 31 755 C1 It is considered that as the closest prior art another kelly linkage extension is known. The extension of the DE 198 31 755 C1 has a hollow cylindrical extension piece, which is connected to the lowermost member of the telescoping Kelly linkage, and which pushes in the retracted state on the tubes of the hereby extended Kelly linkage. Again, however, the maximum achievable Drill depth increase limited because the length of the hollow cylindrical extension piece is limited by the length of the retracted Kelly linkage.

The object of the invention is to provide an extension for attachment, in particular for attaching, to a drill pipe, for example to a Kelly drill pipe, with which the maximum achievable drilling depth can be increased particularly far with particularly high reliability and easy and quick handling.

The object is achieved by a drill pipe extension with the features of claim 1. Preferred embodiments are given in the dependent claims.

The extension according to the invention is characterized in that it comprises a plurality of telescoping tubular elements, which are arranged in the radial direction and which are mutually displaceable in the axial direction, wherein the linkage connecting device and the tool-connecting device are respectively arranged on different tubular elements, and the tubular element , on which the linkage connection device is arranged, is located at least partially in the radial direction within that tube element on which the tool connection device is arranged.

A first aspect of the invention may be seen to provide the drill string extension telescopically with a plurality of tubular members which may be telescoped apart for drilling and which may be telescoped to pull the drilling tool. In contrast to a Kellyverlängerung with only a single, rigid tube section, as for example from the DE 198 31 755 C1 is known, a significantly increased drilling depth increase can be achieved with the invention telescopic extension. Because similar to a Kelly linkage described above, the maximum additional length is the greater the more tubular elements are provided even with a telescopic Kellygestängeverlängerung invention.

Another basic idea of the invention can be seen in arranging the drilling tool on the outermost tubular element of the extension, and the drill pipe to be extended and thus the connection to the drill drive at the innermost Provide tubular element. Thus, in the extension according to the invention, an arrangement is provided which is exactly inverse to the arrangement used in a conventional Kelly linkage. For in a conventional Kelly linkage the drill drive are contrary to the theory of the outermost Kelly tube and the drilling tool on the innermost Kelly tube arranged on which the support cable is attached.

• Werden entsprechend der Erfindung die Rohrelemente zum Zwecke der Verlängerung eines bestehenden Kellygestänges eingesetzt, so steht, anders als beim Kellygestänge selbst, zum Sichern des jeweils freien Rohrelements kein Tragseil zur Verfügung, denn dieses Tragseil ist zum Betrieb des zu verlängernden Kellygestänges erforderlich. Ist aber kein Tragseil zum Sichern des freien Rohrelementes vorhanden, so würde dieses freie Rohrelement einfach durch Schwerkraftwirkung herabfallen, wenn die Verbindung zum benachbarten Rohrelement beim Teleskopieren gelöst wird. Daher muss die zur Verlängerung eingesetzte Rohrelementekombination beim Teleskopieren durch eine zusätzliche, in der Regel im Bereich des Bohrlochmundes angeordnete Abfangvorrichtung gesichert und fixiert werden, um zu verhindern, dass einzelne Rohelemente herabfallen. Insbesondere ist es erforderlich, dasjenige Rohrelement, an welchem das Bohrwerkzeug angeordnet ist, mit der Abfangvorrichtung zu sichern, damit dieses Rohrelement nicht aufgrund des Gewichtes des Bohrwerkzeuges herabfällt.

It has surprisingly been found that when used on a boom extension, the arrangement of the invention is significantly more advantageous than the reverse arrangement, which is used in known Kelly linkages used. In particular, with the arrangement according to the invention, the handling of the extension can be significantly improved and also a further drilling depth increase can be achieved, with these advantageous effects set especially when the telescoping tube elements are used according to the first idea of the invention for extending an existing linkage. These effects, which are based on special geometrical conditions, are explained in detail below. For the sake of simplicity, the explanation will be given using the example of a pipe combination with only two telescoping pipe elements. However, this example can also be extended to pipe combinations with several pipe elements:

• If, according to the invention, the tubular elements are used for the purpose of extending an existing Kelly linkage, then, unlike the Kelly linkage itself, to secure the respective free tubular element no carrying rope available, because this supporting rope is required to operate the Kelly linkage to be extended. However, if there is no carrying cable for securing the free pipe element, then this free pipe element would simply fall down by gravity when the connection to the adjacent pipe element is released during telescoping. Therefore, the tube element combination used for the extension must be secured and fixed during telescoping by an additional, usually in the region of the wellbore mouth catching device and to prevent that individual raw elements fall down. In particular, it is necessary to secure that pipe element on which the drilling tool is arranged with the interceptor, so that this pipe element does not fall due to the weight of the drilling tool.

Would you now, as in a conventional Kelly linkage, arrange the drilling tool on the inner tube member, so when pushing apart this inner tube element should be fixed to the interceptor at the borehole mouth. Of this inner tube element is, however, only a small part, namely the lower end of the tube free before sliding apart, because the rest of the inner tube member is covered before sliding apart from the outer second tube member. So if you wanted to arrange the drilling tool on the inner tube element as known in a conventional Kelly linkage, you would need to slide apart the free lower tube end of the inner tube and fix with the interceptor at the borehole mouth. However, this free lower tube end of the inner tube, which would have to be fixed, is at the same time the end of the tube combination, which is formed by the two tube elements together. Thus, if one were to arrange the boring tool on the inner tubular element, as known from a conventional Kelly linkage, the tube combination, which consists of the two tubular elements, would have to be fixed to the borehole mouth at the time of telescoping.

However, this would have two generally undesirable consequences: Firstly, since the tube combination festläge at the bottom, would be in the solid tube combination, the length of the entire combination over the fixation point, that is, there were two lengths of tube over the fixation point. For these two lengths of pipe should be provided according to free height. However, since only limited space is available for the free height on a drill, the pipe lengths would have to be reduced accordingly, which would lead to a reduction of the additional drilling depth. Secondly, in this end-side fixation, the point at which the two tube elements must again be connected manually after pushing them apart would not be where the tube is fixed. Because this point, at which the pipes must be reconnected, is located at the transition between the two pipe elements, and thus a pipe length away from the fixed point, that is, at a vertical pipe run a pipe length above the fixed point. However, this means in practice that a worker would have to laboriously climb on a ladder or stage for manual connection of the pipe combination in order to work a pipe length above the borehole mouth fixed point.

The conditions in the arrangement according to the invention are completely different. Since according to the invention the drilling tool is arranged on the outer tube element, it is this outer tube element which has to be fixed when pushed apart so that the drilling tool does not fall down. However, this outer tubular element is not covered and can thus be intercepted and fixed at any height contrary to the arrangement described above. In particular, the outer tubular element can thus be gripped at the point that comes to lie in the middle of the pipe combination with the pipe combination pulled out. However, this means that only one pipe length is available when the pipe combination is extended above the fixed point. Therefore, space must be provided on the drill for only a single length of pipe so that longer pipe elements can be used, increasing the maximum depth of drilling. On the other hand, the point at which the pipes must be reconnected after removal, in the area of the fixed point and not a tube length above, and is thus particularly accessible.

According to the second basic idea of the invention, according to which the tool is arranged on an outer tube element, in particular on the outermost tube element, and the linkage to be elongated on a further inner tube element, a particularly large increase in drilling depth is thus achieved with particularly good handleability.

Thus, a telescopic extension according to the invention is given, which can be extended and shortened at the borehole by being pushed apart or pushed together like a kelly linkage. However, compared to a kelly linkage, the arrangement of the individual tube elements is reversed. In particular, according to the invention, the largest, outer tube facing the borehole, that is usually arranged at the bottom, whereas the innermost, smallest pipe borehole facing away, that is usually arranged at the top.

As far as in the context of the invention of the axial direction and the radial direction is mentioned, these directions should generally refer to the longitudinal axes of the individual tubular elements, that is, the radial direction is thus in particular the direction perpendicular to the longitudinal axis of preferably coaxially arranged one inside the other Pipe elements runs.

For example, the tubular elements may be formed with a round cross-section, in which case a torque transmission can take place via entrainment strips. Particularly in this case, it is thus advantageous for a particularly reliable torque transmission that at least one of the tubular elements has axially extending entrainment bars for transmitting torque to an adjacent tubular element. But it can also be a square, for example, square or triangular pipe cross-section can be selected. In this case, the cross-sectional shape itself can be used for torque transmission, so that corresponding entrainment can be omitted. The innermost tube could also be solid for a particularly good power consumption. However, hollow tubes are often preferred for reasons of weight.

The drilling tool may in particular be a drilling screw or a drilling bucket. The invention also includes an arrangement in which a drilling tool is arranged on the tool connection device of the extension and / or in which a drill string is arranged on the linkage connection device.

The linkage connection device and / or the tool connection device may have, for example, polygonal profiles for torque transmission. Preferably, square profiles are provided. Conventionally, the linkage connecting device can thus preferably have an inner polygonal profile, that is to say a sleeve, and the tool connecting device can have an outer polygonal profile. Accordingly, the linkage connection device expediently has a Kellybox and the tool connection device has a Kellyvierkant. The linkage connecting device is expediently arranged on the side facing away from the borehole, that is to say generally at the top of the underlying tubular element, and the linkage connecting device on the side facing the borehole, that is to say generally on the underside of the underlying tubular element.

The handling of the extension according to the invention can be further simplified in that on at least one of the tubular elements, a catch means for supporting the respective tubular element, in particular at the borehole mouth, is provided. For example, the interception device may have a catching element that protrudes from the lateral surface of the tubular element, so that it can be brought in the area of the wellbore mouth to rest. Preferably, all the pipe elements each have such a catching device, possibly with the exception of the inner pipe element, on which the linkage connecting device is arranged, and therefore may not need to be supported. However, a catch device may also be advantageous, for example for assembly purposes, on this inner tube element. An interception device according to the invention facilitates the fixation of the respective free tube element combination when pushing apart or pushing together the extension.

It is particularly expedient that the interception device is arranged in a rod-side end region of the respective tubular element, in particular in an end region facing the Kelly linkage to be extended. This may mean that the interception device is arranged in a region of the respective tubular element which faces the linkage connecting device, that is to say that the intercepting device is preferably closer in the axial direction to the end of the tubular element which faces the linkage connecting device. as at the end, which faces the tool-connecting device. According to this embodiment, the respectively intercepted pipe element is at vertical linkage under the interception device. The intercepted pipe element can thus be advantageously arranged during interception in the borehole interior, so that no corresponding clearance on the drill is required. This in turn has a positive effect on the achievable drilling depth.

If at least one of the pipe elements has a catching device, it is particularly advantageous that this catching device has at least one catching element, which projects from the respective pipe element preferably in the radial direction. For example, a plate may be provided as the intercepting element, preferably a ring plate which surrounds the respective pipe element, in particular in an upper region of the pipe element. As a capture element but can for example also be provided a Abfanggabel. Such a preferably slidable Abfanggabel may have two legs which extend on opposite sides of the respective pipe element. Possibly, as a catching element and a simple Be sufficient intercepting rod. Preferably, the interception element is arranged on the lateral surface of the respective tubular element.

The extension according to the invention can basically be used both in cased boring and uncased boring. When cased drilling the interceptor is suspended for catching expediently on Bohrrohrkragen the drill pipe. When uncased drilling, the interceptor can rest directly on the borehole mouth.

For a particularly reliable handling, it is expedient that the intercepting element has at least one hook element. In particular, the intercepting element for forming the hook element can have at least one angled limb which points towards the tool connection device, that is to say generally downwards.

It is further preferred that the intercepting element is located radially within the drilling cross section of the drilling tool. According to this embodiment, the cross section, which is swept by the intercepting element when rotating the extension about the longitudinal axis of the tubes, within the Bohrquerschnitts of the drilling tool. This prevents the interceptor abuts the borehole wall, when the corresponding pipe element is introduced into the borehole. If a cross-section smaller interception element is used, it may be provided to exert a radially directed force on the extension for the purpose of interception, so that the longitudinal axis of the extension is slightly tilted with respect to the longitudinal axis of the already created borehole, and thus the intersecting cross-sectional interceptor over can survive the borehole wall. Alternatively or additionally, it may be provided for intercepting by means of a cross-section smaller interception element to provide the interception element in the radial direction adjustable on the respective tube element, or temporarily provide an additional cross-sectional larger edition, on which in turn rests the interceptor.

A further embodiment of the invention consists in that the intercepting element is detachably arranged on the respective tubular element. According to this embodiment it can be provided to arrange the intercepting element only intermittently for interception on the tubular element. As a result, the total weight can be reduced and, moreover, it can be prevented that the intercepting element gets into the borehole. in this respect The invention provided on each pipe element interception device can also consist only in a receptacle which is adapted to fix the interception element. Such a trained as a recording interception device, for example, have at least one recess or at least one stop.

In particular, when unperforated drilling, it may be advantageous that a support for laying on the borehole mouth is provided on which in turn rests the interceptor. As a result, damage in the region of the borehole mouth can be avoided by the interception device.

Furthermore, it is advantageous according to the invention that the extension has locking means with which adjacent tubular elements for transmitting axial forces and / or torques can be locked together. These locking means allow a transmission of forces and / or moments from the drill string via the axially displaceable tubes to the drilling tool. If axially extending carrier strips or other means for transmitting torque between adjacent tubular elements are provided, it may be sufficient that the locking means are set up only for the transmission of axial forces. In principle, the locking means can serve both for the transmission of axial forces and for the transmission of torques.

It is particularly preferred that the locking means comprise at least one bolt, which is preferably radially adjustable with respect to the pipe elements. For example, it may be provided that the bolt engages for locking in a corresponding recess of the respective adjacent tubular element. For a particularly simple operability, a guide slot for the bolt can be provided. In particular, in this case, the bolt may also have a bayonet lock, with which the bolt can be locked in the inserted state.

Alternatively or additionally, it can be provided that the locking means have locking pockets and corresponding projections which are arranged on adjacent tubular elements. These latch pockets and projections may, for example, form a bayonet lock, the adjacent tube elements in the axial direction guaranteed. According to this embodiment, a lock can be effected by relative rotation of individual pipe elements to each other about their longitudinal axis.

In principle, the extension according to the invention can be realized with only two tubular elements. For a particularly high drilling depth, however, it is advantageous that, seen in the radial direction, at least one further tubular element is arranged between the tubular element on which the linkage connecting device is arranged, and the tubular element on which the tool connecting device is arranged. According to this embodiment, at least three pipe elements are provided telescopically.

The operational reliability can be further increased by providing a stop for at least one further tube element on at least one tube element, in particular on the tube element on which the linkage connection device is arranged, this stop being arranged in particular in the region of the linkage connection device can. According to this embodiment can be prevented in a particularly simple manner that the remaining pipe elements slip over the linkage connection means to the linkage upwards. For example, it can be provided that the said stop acts for all further tube elements. However, it can also be provided that the individual pipe elements successively have a stop for the respectively adjacent outer pipe element. A stop can also be formed by correspondingly shaped entrainment. In particular, can be provided as a stop bolt strips or latch pockets which extend in the circumferential direction of the tubular elements.

Furthermore, it is according to the invention that the extension between a drill string, in particular Kelly linkage, and a drilling tool is arranged. The invention thus also relates to the unit drill pipe extension drilling tool. If the extension according to the invention is used to extend a telescopic linkage, for example a Kelly linkage, this results in a combination of two telescopic linkage sections, which are connected in series via the linkage connection device.

Depending on the device used, the invention can enable a drilling depth increase with the same device size or a reduction of the device size for the same drilling depth, especially in a partial piping. Compared with a solution with several extension bars that have to be individually pieced together, the invention allows a faster extension or shortening by semi-automatic telescoping. Since no crane work is required, a relatively high drilling speed is made possible even at great depths. In particular, an additional drilling depth gain can be made possible if the number of Kelly tubes of the Kelly linkage (for example three times) is smaller than the number of tube elements of the telescopic extension (for example quadruple). In a Kellytausch on a short Kellygestänge this benefit can be further extended. Compared with a larger drill, the telescope Kellyverlängerung is also relatively cheap. In particular, the invention can be used, for example, in deep special wells, such as in mining / bulk sampling, in the construction of shafts, deep pile foundations and other special cases.

The invention also relates to a drilling rig with a mast, a drill pipe which extends at least partially along the mast, a drill drive arranged on the mast for actuating the drill pipe, and a carrier vehicle for the mast, wherein an extension according to the invention is provided on the drill pipe.

The invention also relates to a method for creating a borehole, in which a boring tool, which is arranged on a drill pipe, in particular Kelly linkage, is drilled, in particular in connection thereto an extension according to the invention between Kelly linkage and boring tool is installed, and the extension for enlarging the maximum drilling depth is extended. It may be advantageous if the bore is first drilled with the simple Kelly linkage and only then the inventive telescopic extension between Kelly linkage and drilling tool is installed. In principle, it can also be provided to drill from the beginning with the combination of Kelly linkage and extension. Preferably, the Kelly linkage and then the extension is extended during drilling first.

Fig. 1

ein erstes Ausführungsbeispiel einer erfindungsgemäßen Verlänge- rung in drei unterschiedlichen Betriebslängen;

Fig.2

ein weiteres Ausführungsbeispiel einer erfindungsgemäßen Verlän- gerung zur Erläuterung der erfindungsgemäßen Abfangelemente; und

Fig. 3 bis 7

ein Bohrgerät mit einem Bohrgestänge, an welchem die Verlänge- rung gemäß Figur 1 vorgesehen ist, in unterschiedlichen Verfah- rensstadien bei der Erstellung eines Bohrlochs.

The invention will be explained in more detail below with reference to preferred embodiments, which are shown schematically in the accompanying figures. In the figures show

Fig. 1

a first embodiment of an extension according to the invention in three different operating lengths;

Fig.2

a further embodiment of an inventive extension to explain the interception elements according to the invention; and

Fig. 3 to 7

a drill rig with a drill string, on which the extension according to FIG. 1 is provided at different stages of the process of creating a borehole.

A first exemplary embodiment of an extension 10 according to the invention is shown in FIG. 1 in various stages of operation, with an almost completely retracted state on the left side, an extended state on the right side and an intermediate state in the middle.

As FIG. 1 1, the telescopic extension 10 has a total of three telescoping tube elements 1 ', 1 "and 1'" which are arranged coaxially with one another coaxially with respect to the drilling axis 99. The tube element located in the radial direction, that is perpendicular to the drilling axis 99, is in the Figures with the reference numeral 1 ', the outermost tubular element by the reference numeral 1''' and the radially intermediate tubular element with the reference numeral 1 "marked.

At the lower end of the extension 10, a drilling tool 60 is provided, which is designed as a drilling bucket in the illustrated embodiment. This drilling tool 60 is arranged on the outer, lowest-lying tube element 1 "', for this purpose the tube element 1'" has a tool connection device 19, which is designed as a kelly square FIGS. 2 to 7 illustrated drill pipe 50 is provided at the opposite end of the extension 10, a linkage connecting device 18. This linkage connecting device 18 is designed as a square profile.

At the middle tube element 1 "radially adjustable bolts 40" are provided with which the middle tube element 1 "on the inner tube element 1 'can be set. Likewise, bolts 40 "'are provided on the outermost tubular element 1'", which serve to fix the outermost tubular element 1 '"on the middle tubular element 1". These bolts 40 "and 40"'form the connecting means which secure the tubular elements 1 to each other during the drilling operation, and which therefore have to be solved for telescoping or Ausscheleskopieren the tubular elements 1.

As FIG. 1 further shows, is at the lower, outer tube member 1 "'a plunger 24 for actuating, in particular for opening, designed as a drilling bucket drilling tool 60 is provided.

Another embodiment of an extension 10 according to the invention is shown in FIG FIG. 2 shown. According to the embodiment of the FIG. 2 at the middle pipe element 1 "a catching device 3" and at the outer pipe element 1 '"a catching device 3"' are arranged The catching devices 3 serve to catch the pipe element 1, on which the respective catching device 3 is arranged, at the borehole mouth 70, if the corresponding bolts 40 are released for telescoping, so that the corresponding pipe element 1 does not fall by gravity into the borehole 90. In the exemplary embodiment shown, the interception devices 3 each have a rod-shaped or fork-shaped intercepting element 30, which is located in an upper region of the respectively underlying Tube element 1 is arranged, that is, in a region of the tubular element 1, which faces away from the tool connection device 19 and the drilling tool 60 'The interception elements 30 are formed as radial webs which project from the respective tube element 1. Radially on the outside, the interception elements 30 are bent over , so that hook elements 31 are formed are, which point down to the drilling tool 60. As shown by the example of the middle tubular element 1 ", the respective tubular element 1" can be hooked on the borehole mouth 70 via these hook elements 31. In particular, the intercepting element 30 can be hooked into the tube collar 36 of a drill pipe 37. However, the intercepting elements 30 can also be used as Preferably, a plurality of hook elements 31 may then be provided spaced apart on the circumference of the respective intercepting element 30.

As FIG. 2 Furthermore, the connecting means designed as a bolt 40 are provided above the respective intercepting element 30, that is to say on the side facing away from the drilling tool, on the respective tubular element 1. Like on the Pin 40 "and the associated interception element 30" can be seen, thus the bolt 40 "is easily accessible when the associated interception element 30" is mounted.

As FIG. 2 also shows, the individual interception elements 30 are smaller in cross-section compared with the drilling tool 60 'is formed, which is designed in the illustrated embodiment as a drill screw. This allows the scavengers 3 to enter the borehole 90 without damaging the borehole wall. To intercept, as in FIG. 2 shown, via the drill pipe 50 a radially directed force exerted on the extension 10, so that the extension 10 bends slightly opposite to the drilling axis and there is a displacement of the current interception element 30 "relative to the borehole 90 and the drill pipe 37, the hooking the hook element 31 "allows. Alternatively, it may be provided to attach the interception element only temporarily before interception and subsequently take it off again. This can be realized in a particularly simple way with Abfanggabeln.

The FIGS. 3 to 7 illustrate the use of the extension 10 of the FIG. 1 in a method for creating a borehole 90, wherein the FIGS. 3 to 7 show the different process steps in the Bohrlochcherstellung.

In particular FIG. 3 shows a drill 80 is provided for this purpose. This drill 80 has a carrier vehicle 83 which carries a mast 81. At this mast 81 a drill drive 82 is arranged longitudinally displaceable. Along the mast runs a drill string 50, on the underside of which the extension 10 is arranged via the linkage connection device 18. At the bottom of this extension 10, in turn, the drilling tool 60 is arranged.

FIG. 3 shows the drill 80 in a position for the assembly or disassembly of the extension 10 or for the emptying of the drilling tool 60, in which the drill pipe 50 and the extension 10 are retracted.

If the extension 10 is to be extended for a drilling depth increase, first the outer tubular element 1 '"is intercepted and the bolts 40"' arranged thereon are released FIG. 4 shown.

Subsequently, the drill string 50 is raised to extend the extension 10, for example, by means of a mast 80 extending support cable 54. The am Drill pipe 50 fastened inner tubular element 1 'as well as the inner tube element 1' via the bolts 40 "held middle tube element 1" are thereby pulled out of the lower tube element 1 '''and pulled out the extension 10. This condition is in FIG. 5 shown.

Subsequently, the bolts 40 '' locked again, solved the interception and drilled deeper.

If the extension 10 is to be extended even further, then the middle tube element 1 "is intercepted, then the bolts 40" of the middle tube element 1 "are loosened, then the drill pipe 50 is again moved upwards and in this case the inner tube element 1 'from the middle one Pipe element 1 "pulled out. This condition is in FIG. 6 shown. The extension of the extension 10 is thus preferably from the outer tube member 10 "'inwards.

The bolts 40 "of the middle tube element 1" are then locked again and the interception of the central tube element is released. Afterwards you can drill deeper.

FIG. 7 Finally, the maximum achievable drilling depth with completely extended telescopic linkage 50 and fully extended extension 10.

Claims (14)

1. Extension (10) for a drilling rod (50), in particular for a telescopic drilling rod (50), comprising

   - a rod connection means (18) for a connection of the extension (10) to the drilling rod (50) and

   - a tool connection means (19) for a connection of the extension (10) to a drilling tool (60),
   characterized in that

   - the extension (10) has several telescopic pipe elements (1) which are arranged inside each other in the radial direction and movable with respect to each other in the axial direction,

   - whereby the rod connection means (18) and the tool connection means (19) are each arranged on different pipe elements (1' and 1''' respectively), and whereby the pipe element (1'), on which the rod connection means (18) is arranged, is located at least in some areas in the radial direction inside that pipe element (1''') on which the tool connection means (19) is arranged.
2. Extension (10) according to claim 1,
   characterized in that
   on at least one of the pipe elements (1) a retaining means (3) for supporting the respective pipe element (1) at the drill-hole mouth (70) is provided.
3. Extension (10) according to claim 2,
   characterized in that
   the retaining means (3) is arranged in a rod-facing end region of the respective pipe element (1).
4. Extension (10) according to any one of claims 2 or 3,
   characterized in that
   the retaining means (3) has at least one retaining element (30) which protrudes from the respective pipe element (1) in the radial direction.
5. Extension (10) according to claim 4,
   characterized in that
   the retaining element (30) has at least one hook element (31).
6. Extension (10) according to any one of claims 4 or 5,
   characterized in that
   the retaining element (30) is located radially inside the drilling cross-section of the drilling tool (60).
7. Extension (10) according to any one of claims 4 to 6,
   characterized in that
   the retaining element (30) is arranged in a detachable manner on the respective pipe element (1).
8. Extension (10) according to any one of the preceding claims, characterized in that
   the extension (10) has locking means, with which adjacent pipe elements (1) can be interlocked for the transmission of axial forces and/or torques.
9. Extension (10) according to claim 8,
   characterized in that
   the locking means have at least one bolt (40) which is radially adjustable with respect to the pipe elements (1) and/or
   characterized in that the locking means have locking pockets and corresponding protrusions which are arranged on adjacent pipe elements (1).
10. Extension (10) according to any one of the preceding claims,
    characterized in that
    when viewed in the radial direction, at least one further pipe element (1") is arranged between the pipe element (1'), on which the rod connection means (18) is arranged, and the pipe element (1"'), on which the tool connection means (19) is arranged.
11. Extension (10) according to any one of the preceding claims,
    characterized in that
    on at least one pipe element (1') a stop for at least one further pipe element (1") is provided.
12. Extension (10) according to any one of the preceding claims,
    characterized in that
    it is arranged between a Kelly rod and a drilling tool (60).
13. Drilling apparatus (80) comprising

    - a mast (81),

    - a drilling rod (50) which runs at least in some areas longitudinally of the mast (81).

    - a drill drive (82) arranged on the mast (81) for actuating the drilling rod (50), and

    - a carrier vehicle (83) for the mast (81),
    characterized in that
    on the drilling rod (50) an extension (10) according to any one of the preceding claims is arranged.
14. Method for producing a drill-hole (90), in which
    a drilling tool (60) which is arranged on a drilling rod (50) is drilled in,
    characterized in that
    an extension (10) according to any one of claims 1 to 12 is installed between drilling rod (50) and drilling tool (60) and
    the extension (10) is extended for increasing the maximum drilling depth.

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