EP1491716B1 - Method for drilling a borehole and wet boring tool - Google Patents

Abstract

Wet-drilling tool (10) comprises a jacket (15) having a drill bit (8) on its under side and a cover (11) on its upper side provided with at least one passage device for the passage of a liquid, a collecting container (6) for collecting drillings, and a pump device. The passage device has a valve element allowing fluid flow in the direction of the interior (3) of the jacket through the passage device and blocking fluid flow in the opposite direction. The passage device has a tubular dome (20) with at least one lateral inlet opening (21) above the collecting container. The dome is arranged coaxially to the jacket on the cover and has on its upper side a connecting rod connection (28) for attaching a boring rod. Independent claims are also included for: (1) Drilling system comprising the above drilling tool; and (2) Process for creating a hole in the ground using the above wet-drilling tool.

Description

The invention relates to a wet drilling tool according to the preamble of claim 1, a drilling rig according to the preamble of claim 7 and a method for drilling down a bore in the ground according to the preamble of claim 8.

Basically, when drilling, such as pile foundations, a distinction between two methods - the dry drilling and wet drilling.

Since wet drilling involves more construction site equipment and limited mobility of the drilling rig, wherever possible, the dry boring method is applied to crawlers by means of a drill. However, this method has its limitations in the presence of particularly harsh geologies. Compared to wet drilling, the drilling performance decreases and the wear of the drilling tool increases considerably.

If, for example, a pile boring wall has to be embedded in rock, then the drilling progress in non-rocky ground during dry drilling is very good and has only a small fraction of what is otherwise usual in rock. Also the wear is very high. A changeover to the wet drilling process is rarely considered because both the equipment and the personnel are not present at the construction site to properly use a wet drilling rig.

From DE 197 02 533 A1 a drilling device is known. The drill bit is rinsed free with either air or a rinsing liquid. In this case, DE 197 02 533 A1 teaches to feed the drill bit via a line a flushing fluid from a reservoir arranged outside the borehole. A fluid flow is generated by means of a peristaltic pump.

Such a known device requires a comparatively complex arrangement of lines, pumps and fluid reservoirs inside and outside the borehole.

Another drilling device is shown in US 3,430,448. The known drilling device has a core drill pipe, in which a lower chamber and an upper chamber are formed one above the other, which communicate with each other via a valve device. The valve device is designed so that a fluid passage from the upper chamber into the lower chamber is possible, a reverse fluid passage, however, is blocked. By moving the core drill pipe up and down, a liquid flow can be generated on its drill bit, which dissipates dissolved soil material from the drill bit into the upper chamber. For generating the up and down movement and a rotary movement of the core drill pipe this is fixed at its upper end by means of a cover on its drill string.

From US 3,185,226 a further drilling tool emerges. This known drilling tool has a drill pipe, on the bottom side cutting blades are arranged. In the drill pipe, an axially displaceable conveying vessel is provided, can be promoted with the processed soil material to the surface. The conveying vessel has on the bottom side valve flaps, via which soil material, optionally together with rinsing water, can get into the conveying vessel and is retained therein. Furthermore, a weighted piston element is provided in the delivery vessel in order to generate a flow in the delivery vessel.

The object of the invention is to provide a method for sinking a hole in the ground, a wet drilling tool and a drilling rig, which allow a simplified and particularly reliable performing a wet drilling process.

According to the invention, the object is achieved by a method for drilling down a bore having the features of claim 8, a wet drilling tool having the features of claim 1 and a drilling rig having the features of claim 7. Preferred embodiments of the invention are set forth in the respective dependent claims.

In the drilling method according to the invention, the wet drilling tool has a pump device through which fluid from the filling area is caused to flow, which conveys accumulating cuttings into the collecting container.

A basic idea of the invention is to produce the fluid flow in the borehole required for a wet drilling process by the boring tool itself. For this purpose, the wet drilling tool is provided with an independent pump device which sucks in the fluid located in the borehole or causes it to flow in such a way that the ablation region is surrounded and the resulting cuttings are conveyed into the collecting container on the boring tool. Preferably, the pumping energy is given by a rotary and / or lifting movement of the drill string transmitted to the drilling tool.

So there are no costly construction site facilities with a variety of hose lines inside and outside the borehole necessary to perform a wet drilling. A wet drilling is thus cheaper and can also be used flexibly due to the simplified handling.

A preferred embodiment of the method according to the invention is that the fluid flow is generated by a change in volume of a working space arranged in the filling area, wherein in particular the working space is at least partially enclosed by the wet drilling tool. As a result of this volume change, a targeted displacement flow of the fluid in the borehole is generated in a given working space.

For a particularly accurate adjustment of the flow, it is preferred that the working space between the wet drilling tool and on the wet drilling tool pending soil material, in particular a core is formed.

If a Teleskcpgestänge, for example, a telescopic Kelly rod or a lifting cylinder, used on the drill pipe, it is according to the invention that the change in volume in the working space is caused by a lifting movement of the wet drilling tool in the borehole.

Alternatively, it is possible according to the invention that the change in volume in the working space is caused by a rotational movement of the drill pipe arranged on the wet drilling tool relative to the wet drilling tool. By a corresponding threaded device can be displaced by a rotational movement, which is preferably opposite to the rotation in drilling operation, a kind of displacement piston.

The drilling method according to the invention can not only be pure wet drilling. Rather, it is an embodiment of the invention that for producing the wellbore in the ground is first drilled in a dry boring method by means of a dry boring tool and especially when reaching higher hardness rock, the dry boring tool is removed from the wellbore, the borehole then at least partially filled with a fluid and the drilling is continued with the wet drilling tool in a wet drilling process. In this method, you can always work with the cheapest, depending on the upcoming soil geology drilling method. In principle, the wet drilling tool can also be designed and used as a dry drilling tool, whereby a wet drilling operation is set only after the liquid has been introduced into the borehole.

However, according to the invention it is particularly preferred that a separate dry drilling tool and a separate wet drilling tool are used. It is provided that the dry boring machine and the wet drilling tool are driven by the same drill pipe to which the dry boring tool and the wet drilling tool are interchangeably mounted. Upon reaching a hard rock layer so the dry drill with the drill string is pulled out of the hole and replaced by a wet drill.

In the wet drilling tool according to the invention a pumping device is provided, through which fluid from a filling region of a borehole is displaceable into a flow through which accumulating cuttings can be conveyed into the collecting container.

The wet drilling tool according to the invention is used for the above-described wet drilling method, resulting in the advantages set out above.

An inventive feature is that a jacket tube is provided on the underside of a drill bit, in particular as a removal device, and on the top side a cover with at least one passage device for the passage of a fluid are arranged, wherein the cover and the jacket tube enclose an interior space.

It is according to the invention to provide a passage means in the lid, which allows a fluid passage from an area located outside the borehole into the interior of the wet drilling tool. The passage device is designed by a valve member so that it only allows a directed into the interior fluid passage. When changing the direction of the fluid flow, however, the valve body closes automatically.

In a well at least partially filled with fluid such an arrangement according to the invention allows the formation of a fluid circulation in which fluid from an outside of the wet drilling tool enters the interior, down in the interior of the Nassbohrwerkzeugs to the drill bit, flows around them, and then outside of the Nassbohrwerkzeugs upwards flows. Due to this cyclic flow, cuttings accumulating on the drill bit can be removed and transported from there in an upward direction to the collecting container.

The valve member ensures that there is no fluid flow from the drill bit in Abtragsbereich into the interior and thus enriches no cuttings in the interior. A pumping action, which maintains the circulating fluid flow, can be generated solely by a rotation of the wet drilling tool in the drilling operation and / or a lifting movement of the wet drilling tool. Thus, in a drill according to the invention, in particular, no pumps or reservoirs arranged outside the borehole are necessary, which permits a very simple and cost-effective drilling.

The fluid used is preferably water. But the use of other flushing fluids and suspensions is basically possible. A drill according to the invention can be used in both vertically and vertically inclined boreholes provided that the drilling tool is surrounded by liquid.

In principle, it is possible to carry out the passage device as a simple bore in the lid. According to the invention, however, it is provided that the passage means comprises a tubular dome. Such a tubular dome allows to arrange inlet openings for the supply of fluid in the interior of the lid spaced.

In particular, the inlet openings may be arranged so that the directed into the interior fluid flow is removed in the borehole at such a location at which the contamination of the downhole fluid by cuttings is small. Due to sedimentation of the cuttings in the fluid, the contamination of the fluid generally decreases with increasing height in the borehole, so that the inlet openings are preferably arranged at a distance from the jacket tube and from the lid. According to the invention, the tubular dome has at least one lateral inlet opening.

Another feature of the invention is that the tubular dome is arranged coaxially with the jacket tube on the cover and that a linkage connection for attaching a drill string is provided on an upper side of the dome. In this embodiment, the dome simultaneously serves both the supply of fluid and the transmission of torque from the drill pipe to the wet drilling tool. This allows a particularly inexpensive construction of the drill.

In principle, the valve member may be in the form of any known non-return member. However, it is particularly preferred that the valve member has a spring and / or buoyancy-actuated flap. As a result, a particularly cost-effective design is possible. The buoyancy body may be filled with air or other medium that is lighter than the fluid. In this way, a secure closing and thus a good blocking effect of the flap can be ensured in the case of a fluid flow directed out of the interior.

The spring-actuated flap may be designed to spring-open at a certain fluid pressure and then automatically close again when the fluid pressure drops due to the spring bias.

In principle, it is possible to arrange the valve member at any point in the cathedral. In particular, the valve member may be provided in the inlet opening of the tubular dome. It is particularly advantageous, however, that the valve member is provided in a cross section of the dome. As a result, the valve member can be made particularly simple and safe locking.

Preferably, the valve member is provided on an underside of the dome. Here, the valve body is particularly easy to access for installation and maintenance. However, it is also possible according to the invention to provide a plurality of valve members. In particular, a valve member may be arranged in the cross section of the dome and at least one further valve member in the inlet opening. If a plurality of inlet openings are provided, a valve element is preferably provided in each inlet opening. With an arrangement of a plurality of valve bodies, a circulating fluid flow can be maintained particularly reliably.

In order to produce a strong pumping action on the fluid, it may be advantageous for the linkage connection to have a piston element that can be moved in the dome. The piston element preferably has a cross section which corresponds to an inner cross section of the dome. Preferably, the dome has a circular inner cross-section and also a circular one External cross section on. The piston element is advantageously movable in a longitudinal direction of the dome.

In a particularly advantageous embodiment of the invention, the piston element is movable by rotation of the drill string in the dome. In particular, a method of the piston element can be effected by a reversal of the direction of rotation of the drill string.

It may be advantageous to provide a drilling rotational direction of the drill pipe, which is used to propel the core drill. A rotation of the drill pipe in a direction opposite to the direction of rotation of the drill can then advantageously bring about a downward movement of the piston element and / or towards the interior. Advantageously, then a renewed rotation of the drill string in the drilling rotational direction first causes a reverse movement of the piston member to the starting position, before the core drill is again set in rotation.

When using a movable piston element, it may be advantageous to provide valve elements both in the cross section of the dome and in the inlet openings. As a result, a particularly reliable pumping action can be achieved. The pumping action generated by a piston element brings the liquid flow thus generated to the removal area and causes a flushing of the drilling site and a removal of the cuttings.

In a particularly preferred embodiment of the invention, the drill string is provided in the form of a telescopic Kelly bar. The dome is suitably designed as a cylinder-like component.

To generate a pumping action, it may also be advantageous for the dome to be able to be retracted and extended into the jacket tube. Such extension and retraction of the dome into the jacket tube can be effected in particular by a rotation of the drill string, wherein advantageously a rotation opposite to the direction of rotation causes the retraction. Suitably, in such an arrangement, the valve member is fixed to the casing pipe. Suitably, in this case also further valve members may be provided in the inlet openings. The extension and retraction of the dome in the jacket tube is preferably effected in the axial direction of the dome.

In order to produce a pumping action, it is according to the invention that on the underside of the dome a piston surface with an outer cross section is provided, which substantially corresponds to an inner cross section of the jacket tube. This results in a particularly large pump volume. The dome can then be provided as a piston rod with fluid supply and outlet openings. Suitably, the dome can turn in and out by rotation of the drill string in the casing tube. Suitably, a valve member is arranged on the jacket tube and advantageously also further valve members are provided.

Another feature of the invention is given by the fact that the upper side of the lid a collecting container for cuttings is provided. The collecting container may be a cup-shaped container bounded by the lid or bottom and a tubular wall.

In principle, it is possible to provide a flow of cutted fluid from the drill bit between the casing and a wall of the wellbore. Advantageously, however, at least one flow channel is provided on the drill for the passage of fluid permeated with cuttings. Such a flow channel can be formed, for example, by providing a further tube coaxially with the jacket tube. The flow channel is then formed between the jacket tube and the further tube. The further tube can be made both smaller diameter and diameter larger than the jacket tube.

The at least one inlet opening of the tubular dome is arranged outside of the collecting container and according to the invention above. In this way it can be achieved that only such fluid enters the inlet opening, which is substantially free of cuttings. Suitably, at the at least one passage opening and a particle filter may be provided which impedes a passage of cuttings.

In a particularly suitable embodiment of the invention, a raising and lowering of the drill for generating the lifting movement of the wet drilling tool during a drilling operation is performed time-dependent automatically or triggered by an operator. Rotation of the drill may optionally be maintained or stopped during lifting and lowering.

A drilling rig according to the invention is characterized in that the above-described wet drilling tool is provided as a drilling tool.

Fig. 1

eine teilweise geschnittene, schematische Seitenansicht eines ersten Ausführungsbeispiels eines erfindungsgemäßen Nassbohrwerkzeugs mit geöffneter Klappe,

Fig. 2

eine teilweise geschnittene, schematische Seitenansicht des Nassbohrwerkzeugs aus Fig. 1 mit geschlossener Klappe,

Fig. 3

ein schematischer Längsschnitt eines weiteren Ausführungsbeispiels eines erfindungsgemäßen Nassbohrwerkzeugs mit einem Dom, der in das Mantelrohr einund ausfahrbar ist, und

Fig. 4

ein schematischer Längsschnitt eines weiteren Ausführungsbeispiels eines erfindungsgemäßen Nassbohrwerkzeugs mit einem ein- und ausfahrbaren Dom, an dessen Unterseite eine Kolbenfläche angeordnet ist.

The invention will be further described below with reference to preferred embodiments shown in the drawings. In the drawings show:

Fig. 1

a partially sectioned, schematic side view of a first embodiment of a Nassbohrwerkzeugs invention with open flap,

Fig. 2

a partially sectioned, schematic side view of the wet drilling tool of FIG. 1 with the flap closed,

Fig. 3

a schematic longitudinal section of another embodiment of a Nassbohrwerkzeugs invention with a dome, which is in and out of the casing tube, and

Fig. 4

a schematic longitudinal section of another embodiment of a Nassbohrwerkzeugs invention with a retractable and extendable Dom, on the underside of a piston surface is arranged.

A first embodiment of a wet drilling tool 10 according to the invention is shown in FIGS. 1 and 2. The wet drilling tool 10 has a cylindrical jacket tube 15, at the lower end of which a drill bit 8 is arranged, which forms the removal region 17. In the embodiment shown here, the drill bit 8 has five roller bits 18, which are arranged annularly in the drill bit 8.

At its top, the jacket tube 15 is closed by an annular lid 11. In the annular lid 11, a dome 20 is arranged centrally. The dome 20 is cylindrical and enters on its underside through the lid 11 into an interior 3 of the wet drilling tool 10. At the top of the dome 20, a linkage 28 is provided for a rotationally fixed connection with a drill string, not shown.

On top of the lid 11, a collecting container 6 is arranged for receiving processed cuttings. The collecting container 6 is thereby bounded by the cover 11, the dome 20 and a cylindrical continuation 16 of the jacket tube 15 and is pot-shaped with an annular cross-section. Laterally in the dome 20, a substantially rectangular inlet opening 21 is provided. The inlet opening 21, through which fluid can enter the dome 20 and from there into the interior 3 of the wet drilling tool 10, is formed above the collecting container 6.

On the underside of the dome 20, a flap 25 is provided, which is shown in Fig. 1 in the open state and in Fig. 2 in the closed state. The flap 25 is designed as a check member such that it passes through the dome 20, in the interior 3 directed fluid flow can pass, however, blocks an oppositely directed fluid flow. For this purpose, the flap 25 is formed as a circular plate which is articulated on one side by a hinge 26 on the dome 20. While the flap 25 completely covers the open underside of the dome 20 in the closed state, the flap 25 is tilted in the open state into the interior 3 of the wet drilling tool 10. On the upper side, the flap 25 has a buoyancy body 24.

The embodiment shown in FIGS. 1 and 2 is suitable for generating a fluid flow for the removal of cuttings from the removal area 17 into the collecting container 6 during a lifting movement of the wet drilling tool 10 in the longitudinal direction of the jacket tube 15. The interior 3 of the wet drilling tool 10 forms a working space of a pumping device. An entering into the interior 3 drill core (not shown) acts as a piston element, which causes a change in volume in the fluid-filled interior 3.

When lifting the wet drilling tool 10 in the longitudinal direction of the jacket tube 15, the drill core, not shown, is pulled out of the interior 3. Due to a resulting pressure drop in the interior 3, the flap 25 opens and fluid flows through the inlet opening 21 into the dome 20 and from there into the interior space 3. During the subsequent lowering of the wet drilling tool 10, the drill core (not shown) again enters the interior space 3, so that the fluid pressure in the interior 3 is increased. As a result, the flap 25 is closed. Fluid, which is displaced by the penetrating core from the interior 3, flows past the drill core to the drill bit 8, from where it transports cuttings along the casing tube 15 into the collecting container 6.

Further embodiments of wet drilling tool 10 according to the invention are shown in FIGS. 3 and 4. Components with the same function are denoted by the same reference numerals as in FIGS. 1 and 2 and are not at this point described in more detail. The exemplary embodiment in FIG. 3 differs from that described above in that the dome 20 can be moved in and out of the interior 3 of the wet drilling tool 10. For this purpose, a threaded sleeve 36 is centrally located on the lid 11. The threaded sleeve 36 has on the inside a screw thread, which corresponds to a externally formed on the dome 20 thread. By a rotation of the dome 20 relative to the cover 11 and the jacket tube 15 thus the dome 20 can be moved relative to the cover 11 in the longitudinal direction of the jacket tube 15. The retraction of the dome 20 is limited by an annular upper stop 37, the extension of the dome 20 by an annular lower stop 38. The rotation of the dome 20 is generated by a drill pipe, not shown, which is rotatably connected via the linkage connection 28 with the dome.

With the embodiment of a wet drilling tool 10 shown in FIG. 3, a volume change of the working space arranged in the interior 3 and thus a pumping action for the fluid can be caused by a rotational movement of the drill pipe, not shown. In this case, the dome 20 acts with the flap 25 arranged on the bottom side as a piston element.

The illustrated in Fig. 4 embodiment of a Nassbohrwerkzeugs 10 according to the invention differs from that of FIG. 3, characterized in that the underside of the dome 20, an annular piston surface 31 is arranged. The inner circumference of the annular piston surface 31 corresponds to the outer circumference of the cylindrical dome 20. On the outer circumference of the piston surface 31, a cylindrical ring member 32 is arranged, which bears against a cylindrical inner tube 14. The inner tube 14 is arranged in the interior of the jacket tube 15 and concentric to this. A lower stop 38 is not provided in the embodiment shown in Fig. 4. Its function is taken over by the piston surface 31.

In the embodiment shown in Fig. 4, the working space is formed in the interior of the inner tube 14. A Rotation of the dome 20 relative to the jacket tube 15 causes depending on the direction of rotation an upward or downward movement of the dome 20 and the piston surface 31 arranged thereon relative to the interior space 3, which results in a volume change of the working space and thus a pumping action. Between the inner tube 14 and the jacket tube 15, a flow channel for a directed from the Abtragsbereich 17 to the collecting container 6 stream of cuttings offset fluid is formed.

Claims (14)

1. Wet boring tool (10) having

   - a jacket tube (15) having on the underside a core bit (8) and on the top side a cover (11) with at least one passage device for the passage of a fluid, the cover (11) and the jacket tube (15) surrounding an inner area (3),

   - a collecting container (6) for receiving bore smalls produced, which collecting container (6) is provided on the top side of the cover (11), and

   - a pumping mechanism through which fluid from a filling area of a borehole can be made to flow and as a result of the flow bore smalls produced can be fed into the collecting container (6), wherein

   - the passage device has a valve member, which.allows a fluid flow directed into the inner area (3) through the passage device and blocks said passage device in the case of an oppositely directed fluid flow,

   characterized in that

   - the passage device has a tubular dome (20) which has at least one intake (21) positioned laterally and above the collecting container (6), and that

   - the tubular dome (20) is arranged coaxially with respect to the jacket tube (15) on the cover (11) and that on the top surface of the dome (20) is provided a rod connection (28) for fitting a boring rod.
2. Wet boring tool (10) according to claim 1,
   characterized in that
   the valve member has a spring and/or buoyancy body-operated flap (25).
3. Wet boring tool (10) according to one of the claims 1 or 2,
   characterized in that
   the valve member is provided in a cross-section of the dome (20), particularly on an underside of the dome (20).
4. Wet boring tool (10) according to one of the claims 1 to 3,
   characterized in that
   the rod connection (28) has a piston element, which is displaceable in the dome (20) in axial direction, the displacement of the dome (20) preferentially resulting from a rotation of the boring rod.
5. Wet boring tool (10) according to one of the claims 1 to 4,
   characterized in that
   the dome (20) can be retracted into and extended from the jacket tube (15) in axial direction, wherein retracting and extending the dome (20) preferentially results from rotating the boring rod.
6. Wet boring tool (10) according to claim 5,
   characterized in that
   on the underside of the dome (20) is provided a piston surface (31) with an outside cross-section essentially corresponding to an inside cross-section of the jacket tube (15).
7. Boring plant having

   - a mast,

   - a boring rod displaceably guided thereon with a boring tool and a drive mechanism, through which the boring rod can be driven in rotary manner,

   characterized in that

   - the boring tool is constructed as a wet boring tool (10) according to one of the claims 1 to 6.
8. Method for sinking a bore in the ground, wherein

   - a wet boring tool (10) with a removal area (17) is used for making or advancing a borehole,

   - the borehole is at least partly filled with a fluid forming a filling area in the borehole,

   - a fluid flow at least temporarily washes round the removal area (17), the bore smalls occurring in the removal area (17) being conveyed away by the fluid flow to a collecting container (6) located in the borehole, and

   - the wet boring tool (10) has a pumping mechanism by means of which fluid from the filling area is made to flow, which flow conveys the bore smalls which occur into the collecting container (6),

   characterized in that

   - a wet boring tool (10) according to one of the claims 1 to 6 is used.
9. Method according to claim 8,
   characterized in that
   the fluid flow is produced by a volume change to a working area located in the filling area and in particular the working area is at least partly surrounded by the wet boring tool (10).
10. Method according to claim 9,
    characterized in that
    the working area is formed between the wet boring tool (10) and soil material arising at said wet boring tool (10) and in particular a core.
11. Method according to one of the claims 9 or 10,
    characterized in that
    the volume change in the working area is brought about by a lifting movement of the wet boring tool (10) in the borehole.
12. Method according to one of the claims 9 or 10,
    characterized in that
    the volume change in the working area is brought about by a rotary movement relative to the wet boring tool (10) by a boring rod positioned at said tool (10).
13. Method according to one of the claims 8 to 12,
    characterized in that
    for making the borehole in the ground, firstly using a dry boring method and a dry boring tool boring takes place and in particular on reaching rock with a higher hardness level the dry boring tool is removed from the borehole, which is then at least partly filled with a fluid and boring is continued in a wet boring method using the wet boring tool (10).
14. Method according to claim 13,
    characterized in that
    the dry boring tool and the wet boring tool (10) are driven by a boring rod, to which are interchangeably fitted the dry boring tool and the wet boring tool (10).

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