EP0494408B1 - Method and device for enlarging a well - Google Patents

Description

The invention relates to an expanding device for expanding a pilot borehole according to the preamble of claim 1. Such a device is known for example from EP-A-350 806.

From EP-A-272 905 a device for expanding an existing pilot borehole is also known, which can be connected at the tip of its conical expansion head to a pipe string laid in the pilot borehole and pulled by it through the pilot borehole. Liquid is fed to the expander head under high pressure through the pipe string. This has a number of channels which are connected to the inner bore of the pipe string. At the radially outward-pointing ends of these channels, nozzles are formed, which generate a fine, high-pressure liquid jet for cutting the soil. By pulling on the pipe string, the conical expansion head is pressed into the soil divided by the liquid jet while simultaneously rotating the pipe string, so that the pilot borehole is widened. The pipe corresponding to the widened borehole is drawn in at the same time as it is widened.

The invention has for its object to provide an expansion device of the generic type, with which the expansion of the pilot hole can also be carried out in dense soil or soil with rock inclusions and which has good maneuverability in curves.

This object is achieved by the features specified in the characterizing part of claim 1.

Advantageous embodiments of the invention are specified in the subclaims.

Figur 1

eine schematische Schnittdarstellung eines mit dem erfindungsgemäßen Aufweitgerät aufzuweitenden Pilotbohrloches,

Figur 2

eine der Figur 1 entsprechende Darstellung eines aufzuweitenden Pilotbohrloches, welches unmittelbar vor dem Aufweiten mit einem geeigneten Gestänge vorgebohrt wurde, wobei das Aufweitgerät an dieses Gestänge angeschlossen ist,

Figur 3

eine Innenschnittansicht eines Gehäuses gemäß einer ersten Variante,

Figur 4

eine Innenschnittansicht eines Gehäuses gemäß einer zweiten Variante,

Figur 5

eine Innenschnittansicht eines Gehäuses gemäß einer dritten Variante,

Figur 6

eine Außenansicht eines Gehäuses gemäß einer ersten Variante,

Figur 7

eine Außenansicht eines Gehäuses gemäß einer zweiten Variante,

Figur 8

eine Außenansicht eines Gehäuses gemäß einer dritten Variante,

Figur 9

eine schematische Schnittansicht eines Dämpfungselementes, das zwischen dem Aufweitgerät und einer Pilotbohrvorrichtung angeordnet werden kann, und

Figur 10

eine teilweise schematische Schnittansicht einer außerhalb des Aufweitkopfes angeordneten Schneideeinrichtung.

The following description in conjunction with the accompanying drawings explains the invention using exemplary embodiments. Show it:

Figure 1

2 shows a schematic sectional illustration of a pilot borehole to be expanded using the expansion device according to the invention,

Figure 2

1 shows a representation of a pilot borehole to be widened, which was pre-drilled with a suitable rod immediately before the widening, the widening device being connected to this rod,

Figure 3

an internal sectional view of a housing according to a first variant,

Figure 4

an internal sectional view of a housing according to a second variant,

Figure 5

an internal sectional view of a housing according to a third variant,

Figure 6

an external view of a housing according to a first variant,

Figure 7

an external view of a housing according to a second variant,

Figure 8

an external view of a housing according to a third variant,

Figure 9

is a schematic sectional view of a damping element that can be arranged between the expander and a pilot drilling device, and

Figure 10

a partially schematic sectional view of a cutting device arranged outside the expanding head.

In a first variant of a method for widening a pilot borehole, a pilot borehole 10 present in the soil 7 between two construction pits B is widened by driving an expanding device 1 into the pilot borehole from one side of the pilot borehole 10 [Fig . 1].

In a second variant of the method, the widened borehole 9 is produced in an operation immediately following the pilot boring process, in that an expanding device 1 is attached to the pilot boring device for the pilot borehole 10, for example a pipe string 21 with a displacement head is connected [Fig. 2]. When the pilot drilling device is withdrawn from the pilot borehole, the expander is guided in the pilot borehole. A static tension can also be applied to the expansion device of approximately 5 tons, preferably connected with a damping element. With its cutting and ramming method of operation, it expands the pilot borehole. Such a pilot borehole 10 can have a diameter of 40-50 mm, for example, and the expanded borehole can have a diameter of 160-200 mm. The pilot drilling device can also supply the expanding device with cutting fluid.

It is common to both methods that the pilot borehole 10 is widened by striking and cutting action and displacing the soil 7. High-pressure cutting fluid is used to cut the soil. With these methods, part of the cutting fluid supplied to cut the soil can be used to reduce the friction between the borehole wall and the pipe to be drawn in.

With this cutting action, cutting fluid is pressed in a manner known per se under high pressure by jetting a cutting device into the soil to be drilled or widened, as a result of which it is divided up and can thus be better drilled or widened.

A device for carrying out the method explained above is an expanding device in the form of a short ram 1 with a striking device 2 for its independent forward movement. The expander has a cylindrical housing 3 with a front expander head 4 seated thereon and an impact body 5 of the impact device 2, which strikes on the front side inside the housing 3, the individual, associated assemblies being designed as follows. The cylindrical housing shell is shorter than 4 times the housing diameter.

The percussion device 2 has a reciprocating piston 2.1, which is hollow-cylindrical at its rear end, in the housing 3, which is designed as a cylinder, and which is pressurized with compressed air and has control openings 2.2 at its rear end. Its back and forth movement is controlled by a control device 6 with control edges 6.1, which partially projects into the percussion piston 2.1 and which cooperate with the control openings 2.2 arranged in the percussion piston 2.1, in such a way that the percussion piston 2.1 hits the front area 1.1 of the Rammaufweitgeraetes 1 hits and thereby drives the ramming device 1 forward in the soil 7. At the rear end of the housing 3 there is a device 8 for connecting and pulling pipes into the widened borehole 9. The housing 3 is closed with a housing cover 3.7 at its rear end, this housing cover 3.7 having exhaust air openings 3.8 and carrying the control device 6 and lines of the second supply line network for the compressed air [FIG. 6].

In a first variant of the internal structure of a housing, supply lines are provided in the housing wall as a first feed line network 11 for a cutting fluid which is fed to a cutting device [13], this connecting to the cutting device 13 on the one hand and on the other hand to a supply device outside the Borehole, which also supplies the compressed air for the impact device 2, is set up. A second feed line network 12 is provided for connection to the control device 6 on the one hand and the compressed air lines of the supply device on the other hand. [Fig. 3].

In a second variant of the internal structure of a housing, in a modification of the first variant mentioned, a first feed line network 11 for a cutting fluid is not provided in the housing itself, but only in the expansion head for the cutting device 13 integrated in the expansion head and a feed line to one or more lubricating nozzles. This first feed line network 11 is provided with means for connection to a device upstream of the expander head 4, for example a pilot drilling device or a cutting device 13. A second feed line network 12 is provided for connection to the control device 6 on the one hand and the compressed air lines of the supply device of the expander on the other and is arranged in the rear part of the expander [Fig. 4].

In a third variant of the inner structure of a housing, in a modification of the second variant mentioned, the substantially cylindrical housing is designed as a double-tube housing 3, which is suitably connected to the expansion head 4, preferably welded on, and is at its rear end by the double-tube structure Ring nozzle for the lubricating fluid contains. The two housing pipes 3.1, 3.2 are supported at suitable points with spacers 3.3 [Fig. 5].

In a first variant of the outer shape of a housing, the housing is designed as a cylindrical housing 3 [Fig. 6].

In a second variant of the outer shape of a housing, the essentially cylindrical housing is designed as a waisted housing 3, in which guiding rims 3.4 are arranged on both housing ends and a section 3.5 of smaller diameter is provided between them to facilitate cornering [Fig. 7].

In a third variant of the outer shape of a housing, the essentially cylindrical housing is designed as a stepped housing 3, in which a guide wedge 3.4 is arranged at the front end of the housing and then a region 3.6 of the housing, which is smaller in diameter and connects to this, connects to it Facilitation of cornering is provided [Fig. 8th].

The expanding head 4 is for receiving a part of the impact device 2 as a hollow head 4.1 educated. It is firmly connected, preferably welded, to the housing 3 of the impact device 2, the connection point or the weld seam being located behind an impact point 4.2 of the impact body 5 arranged on the end face. When this part of the striking device 2 is received, the striking piston 2.1 of the striking device 2 protrudes temporarily or permanently with part of its length into the hollow head [FIG. 4, 5].

The cutting device 13 is arranged in a first variant in front of the expansion head 4 and connected to it, preferably screwed. This cutting device 13 has between a front and a rear connection device 13.1 or 13.2, preferably corresponding parts of pipe fittings 13.1.1, 13.2.1, in particular union nut pipe fittings 13.1.1, 13.2.1, and a central cutting part 13.3, which in the Has region of its surface in suitable directions nozzles 15.1 of the cutting device 13 for the discharge of cutting fluid under high pressure, which are preferably directed substantially forward, substantially rearward and essentially radially and are located at the ends of internal conduits 13.4 which are connected to a central feed channel 13.5 are connected. The central feed channel 13.5 is connected by means of the pipe fittings 13.1.1, 3.2.1 to external cutting fluid circuits, for example a pilot drilling device 14 or the expansion device 1. The expanding device can also be connected to the pilot drilling device 14 by means of the cutting device 13 [FIG. 10].

In a second variant, the cutting device 13 can be arranged integrated in the expansion head 4. In the cutting device 13, the internal line channels 13.4 are provided for forwarding the cutting fluid to means for exiting cutting fluid under high pressure in the expansion head 4, these fluid lines being connected to corresponding lines of a feed line network of the cylindrical housing 3 [Fig. 4, 5].

In both cases, the means of the cutting device 13 for the discharge of cutting fluid under high pressure are nozzle-shaped openings 15.1, which are designed as nozzle insert pieces 15.1.1 and are inserted at the free end of the internal duct 13.4 of the cutting device 13. The nozzle insert pieces 15.1.1 are preferably made of industrial gemstones. The axis direction points at least a part of the jet-shaped openings 15.1 at least partially in the direction of advance of the borehole, ie with a directional component to the front and some of the nozzle-shaped openings 15.1 at least partially opposite to the direction of advance of the borehole, ie with a directional component to the rear.

At the rear end of the expander 1 there is at least one lubricating nozzle 16 for the discharge of cutting fluid on the jacket side of the tube drawn in by the expander 1 for the lubrication of its retraction movement. The lubricating fluid is part of the cutting fluid and is supplied from the first feed line network 11 through a lubrication line 17 connecting the lubricating nozzles 16 to the first feed line network. This lubricating nozzle 16 can also be designed as a ring nozzle and extend practically over the entire circumference of the rear end of the housing [Fig. 5].

It is possible to connect the expansion device to a pilot drilling device (not shown) by means of a damping element 18. The pilot drilling device can be a static pilot drilling device of known design and consists of a pipe string 21 and, on the one hand, a digging head connected to it with integrated high-pressure cutting nozzles and, on the other hand, a connected supply and pressure device [not shown] for applying the necessary static pressure for driving the pilot forward -Drilling tools exist in the ground. The expansion device 1 is also connected to the cutting fluid line of the pilot drilling device.

The damping element 18 is preferably a hydraulically acting damping element. It is necessary if the expansion device is connected to a pilot drilling device in the retreat and consists of a cylinder 18.3 which can be connected to the expansion device 1, for example with a pipe screw connection 19 and which contains a piston 18.1 inside, which, like its piston rod 18.2, has a central bore 18.5. The piston rod can also be connected to a pilot drilling device by means of a pipe screw connection 19. A compression spring 18.6 is clamped between piston 18.1 and cylinder 18.3. In addition, 18.1 connecting bores are provided in the piston for connecting the two cylinder spaces 18.3.1, 18.3.2, which serve as damper bores by using the cutting fluid contained in the cylinder 18.3 with each impact of the ramming Expander 1 is pressed from one cylinder chamber while damping the impact of the expander in the other cylinder chamber. With such a design of the damping element 18, a constant pull is exerted on the piston rod 18.2 by the pilot drilling device, which is in its retraction phase from the pilot bore 10. Such a damping element is required so that the strikes of the short rams are as far as possible not transferred to the pilot drilling machine and this is prevented from being destroyed [Fig. 9].

With the above-mentioned modules or modified versions of them, various variants of expansion devices can be produced, in particular the following:

In an expansion device 1 of the first type [Fig. 3], a housing is provided in a first variant of the inner structure, which contains a striking device 2 as described above, which is connected with its second line network to the compressed air lines of the supply device of the expanding device 1. The top of the expander 1 is connected to a cutting device 13, the supply of cutting fluid from the supply device of the expander 1 through the housing.

In an expansion device 1 of the second type [Fig. 4], a housing is provided in a second variant of the inner structure, which contains an impact device 2 as described above, which is connected with its second line network to the compressed air lines of the supply device of the expansion device. The first line network of the casing is connected via the head tip of the expander 1 to a damping element 18 and this to a pilot drill pipe of a pilot drill device, from which the cutting fluid is also supplied.

In a third type expansion device 1 [Fig. 5], a housing is provided in a third variant of the inner structure, which contains an impact device 2 as described above, which is connected with its second line network to the compressed air lines of the supply device of the expander. The first line network of the housing is connected via the head tip of the expander 1 to a damping element 18 and this to a pilot drill pipe of a pilot drill device, from which the cutting fluid is also supplied.

HOW IT WORKS

In the first variant of the method, the ramming and cutting expansion device drives into an existing pilot borehole 10 and, as a result of its larger diameter compared to the pilot borehole, expands it, thereby displacing the soil.

In the method according to the second variant, on the other hand, the ramming expansion device, which is connected to a pilot drilling device at its tip by means of a damping element 18, drives itself into a pilot drilling hole 10 between two construction pits. The pilot drilling device, which is withdrawn from the pilot borehole 10, pulls on the expander 1 additionally with a pull of approx. 5 tons. Due to its larger diameter compared to the pilot borehole 10, the latter is expanded.

Since the pipe to be pulled in can be connected to the ramming widening device, this is not only also pulled in in the same operation as the widening, but it can also be pulled in more easily, and thus over a longer length, than with the known methods due to the jerky movements. especially with the widening method using static tension. This summary of one operation, even over longer lengths, saves an enormous amount of working time and also equipment and operating personnel. As a result, a pipe can be drawn in much more cheaply than previously with the known methods and known devices.

The combination of ramming and cutting the soil significantly increases the driving performance and it can also be used in very hard soils and rock interspersed soils, which are no longer or only very poorly and laboriously processed with the static [pushing and pulling] methods previously used could be worked. This not only significantly increases the performance and thus the profitability, but also the technical applicability.

The expansion device in the form of short rams can also follow the bores of the pilot hole without any problems due to its short design compared to normal ram boring machines. Due to its striking mode of operation, it is also able to smash larger rock inclusions which are adjacent to the pilot borehole To hit side. Particularly in the versions with the waisted or offset housing, there is particularly good cornering ability even for smaller radii.

The cutting and ramming expander, in each of the variants with an integrated cutting device, with a cutting device in front, with the supply only from behind, the supply from behind and from the front, with a ring nozzle as a lubricating nozzle, with individual lubricating nozzles etc., is caused by the compressed air Supply device of the expander is operated like a one-way earth ram with a cadence that can be determined by the control geometry of the control device belonging to the impact device.

Simultaneously with the ramming movement, a cutting fluid is supplied to the expanding device by a supply device [the supply device for the pilot drilling device or the supply device of the expanding device itself] which is dependent on the respective process variant and is pressed into the soil under extremely high pressure from the cutting nozzles of the cutting device and cut it up with it. This also allows rock inclusions to be cut and subsequently crushed by the striking movement of the ramming. By lubricating the surface of the pipe to be pulled in, even with large pipe lengths, most of the energy is used for the advance and is not used for pulling in the pipe. Therefore, very long pipelines can be pulled in more economically than before. This saves the set-up work, since fewer excavation pits have to be excavated for the individual sections, because these sections can be longer. This eliminates the risk of a purely static train or pressure that the large jacket friction forces acting on the pipe to be pulled in can no longer be overcome due to the surrounding soil.

Claims (9)

1. Expanding apparatus for expanding a pilot bore hole (10), comprising a cylindrical casing (3), whose length is shorter than four times the casing diameter, a front expanding head (4) with a cutting device (13), an impacting device (2) for the automatic forward movement of the expanding apparatus (1) in the soil with an impact body (5) frontally impacting in the interior of the casing (3) and a device (8) for connecting a pipe (R) to be drawn into the expanded bore hole (9), the expanding head (4) having a hollow construction for the at least temporary reception of the impact body (8), characterized in that the cutting device (13) has nozzle-like openings (15.1) for the discharge of high pressure cutting fluid and which are formed in the vicinity of the expanding head (4) at the free end of internal line channels (13.4) and have three different axial directions, the axial direction of a first part of the nozzles (15.1) being substantially parallel to the casing longitudinal direction, the axial direction of a second part of the nozzles (15.1) being substantially perpendicular to the casing longitudinal direction and the axial direction of a third part of the nozzles (15.1) being substantially perpendicular to the wall of the expanding head (4).
2. Expanding apparatus according to claim 1, characterized in that the cutting device (13) is positioned upstream of the expanding head (4) and is connected thereto.
3. Expanding apparatus according to claim 1, characterized in that the cutting device (13) is integrated into the expanding head (4).
4. Expanding apparatus according to one of the claims 1 to 3, characterized in that the expanding head (4) is welded to the casing (3), the welding seam being positioned behind a frontal impact point (4.2) of the impact body (5).
5. Expanding apparatus according to one of the claims 1 to 4, characterized in that at its free end the expanding head (4) has means for the connection of further implements, particularly high pressure lines for the cutting fluid.
6. Expanding apparatus according to one of the claims 1 to 5, characterized in that at the rear end of the expanding apparatus (1) is provided at least one lubricating nozzle (16) for the discharge of cutting fluid towards the jacket side of the pipe (R) drawn in by the expanding apparatus (1).
7. Expanding apparatus according to one of the claims 1 to 6, characterized in that the substantially cylindrical casing (3) has guide rings (3.4) constructed at both casing ends and a smaller diameter portion (3.5) located between them for facilitating the curved negotiating characteristic of the expanding apparatus.
8. Expanding apparatus according to one of the claims 1 to 7, characterized in that it is connectable with a pilot boring device (14), a damping element (18) being located between the two means.
9. Expanding apparatus according to claim 8, characterized in that supply lines for the pilot boring device (14) can be connected to the expanding apparatus (1).

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