EP0494408A1 - Method and device for enlarging a well - Google Patents

Abstract

A method of enlarging a straight or curved pilot bore hole and subsequently drawing in a pipe is specified in which the pilot bore hole (10) is enlarged with a percussive and cutting action and in such a way as to displace the earth. Here, cutting fluid under high pressure is used for cutting the earth. <??>An enlarging tool for carrying out the method has a cylindrical housing with a front enlarging head and a drive device for moving the tool forward in the earth as well as a device for connecting and drawing pipes into the enlarged bore hole. The drive device is designed as a percussion device [2], having a percussion body [5] striking at the end face inside the housing [3], and has a cylindrical housing length which is shorter than 4x the housing diameter. The enlarging head [4] for accommodating a part of the percussion device is designed as a hollow head [4.1] and can be connected to a cutting device [13] which has means [15] for the discharge of cutting fluid at high pressure, preferably cutting nozzles. <IMAGE>

Description

The invention relates to a method according to the preamble of claim I and an expansion device, preferably for performing the method, according to the preamble of claim 7.

STATE OF THE ART

In a known device [US 46 74 479 - FLOWMOLE] for widening a pilot borehole present in the ground, a conical widening head is connected with its tip to a pipe string laid in the pilot borehole and pulled therefrom through the pilot borehole. In this process, liquid is fed to the expander head under high pressure. This has a number of channels running essentially in the direction of movement and transverse to this, which are connected to the inner bore of the pipe rod. At the outer ends of these channels there are nozzles which generate a fine, high-pressure liquid jet which cuts the soil. By pulling the pipe rods, the conical expansion head is pressed under constant tension and by rotating the pipe rod rotating into the soil divided by the liquid jet, thus expanding the pilot borehole. The expansion process thus consists of a rotating movement and constant, axial pressing of the expansion head into the soil surrounding the pilot borehole. The pipe corresponding to the widened borehole is drawn in at the same time as the widening.

DISADVANTAGE

It is disadvantageous that the pilot borehole can still be created in the case of solid soil or soil interspersed with rock inclusions, since the pilot drilling device was able to bypass rock inclusions laterally, but when expanding these rock inclusions either shifted in the solid soil or parts of should be separated from them. This is not possible with a device of the type described. Even in densely stored soil without rock inclusions, the pilot drill hole in the soil can only be widened by flushing or cutting and applying a static pull. or pressure force is often not possible because the diameter of the Expanding hole is about 3-4 times the diameter of the pilot hole. The cross-sectional area of the pilot bore is increased by 9 to 16 times the cross-section of the expansion bore and thus the jacket surface accordingly. In addition, in the case of purely static tension or pressure, there is a risk that the large jacket frictional forces acting on the pipe to be pulled in can no longer be overcome due to the surrounding earth.

AIM OF THE INVENTION

It is therefore the object of the invention to provide a method for widening boreholes even in solid soil or soil interspersed with rock inclusions, and a widening device in which these disadvantages do not occur.

INVENTION

• Fig.1 die Darstellung der Situation eines aufzuweitenden Pilot-Bohrloches,
• Fig.2 die Darstellung der Situation eines aufzuweitenden Pilot-Bohrloches, welches unmittelbar vor dem Aufweiten mit einem geeigneten Gestaenge vorgebohrt wurde und das Aufweitgeraet an dieses Gestaenge angeschlossen ist,
• Fig.3 innere Form eines Gehaeuses in einer 1. Variante,
• Fig.4 innere Form eines Gehaeuses in einer 2. Variante,
• Fig.5 innere Form eines Gehaeuses in einer 3. Variante,
• Fig.6 aeussere Form eines Gehaeuses in einer 1. Variante [zylindrisch],
• Fig.7 aeussere Form eines Gehaeuses in einer 2. Variante [tailliert],
• Fig.8 aeussere Form eines Gehaeuses in einer 3. Variante [abgesetzt],
• Fig.9 ein Daempfungselement,
• Fig.10 Schneideinrichtung in externer Anordnung.

This goal can be achieved if the features of the characterizing part of claim 1 for the method and the features of the characterizing part of claim 7 for the device are realized according to the invention. In addition, the features of claims 2 to 6 and features 8 to 19 for the device can be carried out in the method. Further details and advantages of the invention result from the description of exemplary embodiments with reference to the drawing. In this shows

• 1 shows the situation of a pilot borehole to be expanded,
• 2 shows the situation of a pilot borehole to be widened, which was pre-drilled with a suitable rod immediately before the widening and the widening device is connected to this rod,
• 3 inner form of a housing in a first variant,
• 4 internal form of a housing in a second variant,
• 5 inner form of a housing in a third variant,
• 6 outer form of a housing in a first variant [cylindrical],
• Fig. 7 outer form of a housing in a second variant [tailored],
• 8 external form of a housing in a third variant [removed],
• 9 a damping element,
• Fig.10 cutting device in external arrangement.

METHOD

In a first variant of the method, 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 pilot borehole 10 is produced in an operation immediately following the pilot boring process, the widened borehole 9 by connecting, for example, a pipe rod 21 with a displacement pipe to the pilot borehole for the pilot borehole 10 Head, an expander 1 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 train of about 5 tons, preferably connected with a damping element, can also be applied. 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 the 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. In 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 and can thus be better drilled or widened.

CONTRAPTION

A device for carrying out the method according to claim 1 can preferably be a ram expansion device, in the form of a short ram 1, with a striking device 2 for its independent forward movement, which is a cylindrical housing 3 with a front expansion head 4 sitting thereon and one inside the housing 3 has impact body 5 of an impact device 2, the individual associated assemblies being designed as follows. The striking device 2 has a cylindrical housing length of the housing shell, which is shorter than 4 times the housing diameter.

This percussion device 2 has a reciprocable in the housing 3 designed as a cylinder, at its rear end hollow cylindrical percussion piston 2.1 as percussion body, 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 the Rammaufweitgeraet 1 runs forward in the soil 7. At the rear end of the housing 3, a device 8 for connecting and pulling pipes into the widened borehole 9 is arranged. 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 that 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 expanding head for the cutting device 13 integrated in the expanding head and a feed line to one or more lubricating nozzles. This first feed line network 11 is connected to this by means of connection to a device upstream of the expansion 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 internal structure of a housing, in a modification of the second variant mentioned, the essentially cylindrical housing is designed as a double-tube housing 3, which is suitably connected to the expansion head 4, preferably welded on, and at the rear end of which is an annular nozzle for the double-tube structure the lubricating fluid contains. The two housing tubes 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 waisted section 3.5 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 with a smaller diameter adjoins this, which for Relief 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 to the housing 3 of the impact device 2, preferably welded, 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].

In a first variant, the cutting device 13 is arranged 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, a central cutting part 13.3, which is in the area means 15 of the cutting device 13 of its cutting surface 13 for the discharge of cutting fluid under high pressure pointing in suitable directions, which are preferably directed essentially forward, substantially rearward and essentially radially and at the ends of internal conduit channels 13.4, which have 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 automatic 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 conduit 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 15 of the cutting device 13 for exiting cutting fluid under high pressure are nozzle-shaped openings 15.1, which are designed as nozzle insert pieces 15.1.1 and are used at the free end of the internal conduit channels 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 nozzle-shaped openings 15.1 at least partially in the direction of advance of the borehole, ie with a directional component to the front. However, it is also possible to have the axis direction of 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 automatic device 1 there is at least one lubricating nozzle 16 for the discharge of cutting fluid to the jacket side of the tube drawn in by the expanding device 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 [1 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 expanding device to a pilot drilling device 14 by means of a damping element 18. The pilot drilling device can be a static pilot drilling device 14 of known design and consists of a pipe string 21, and on the one hand a digesting head 20 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 required static pressure Driving the pilot drill 14 exist in the ground. The expanding device 1 is also connected to the cutting fluid line of the pilot drilling device 14.

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 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 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 14 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, connection bores 18.4 are provided in the piston 18.1 for connecting the two cylinder spaces 18.3.1, 18.3.2, which serve as damper bores, by means of which the cutting fluid contained in the cylinder 18.3 passes through each time the ram is struck Autweitgeraetes 1 from one cylinder chamber is pressed into the other cylinder chamber while damping the blow from the expansion unit. 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 14, 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 transmitted to the pilot drilling device 14 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 tip 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 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 14, from which the cutting fluid is also supplied.

In a third-party automatic device 1 [Fig. 5], a housing is provided in a third 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 automatic unit. 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 14, 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 thereby expands the earth compared to the pilot borehole due to its larger diameter due to its larger diameter.

In the method according to the second variant, on the other hand, the ramming expansion device, which is connected to a pilot drilling device 14 at its tip by means of a damping element 18, drives itself into a pilot drilling hole 10 between two construction pits. The pilot drill 14, which is withdrawn from the pilot bore 10, additionally pulls the expander 1 with a pull of approximately 5 tons. As a result of its larger diameter compared to the pilot bore 10, the latter is expanded.

Since the pipe to be pulled in can be connected to the ramming widening device, it is not only pulled in in the same operation as the widening, but it can also be pulled in more easily, and thus also over a longer length, than with the known methods due to the jerky movements. in particular with the expansion methods using static pull. This summary of one operation, even over larger areas, saves a great deal of working time and also equipment and operating personnel. As a result, a pipe can be drawn in much more cheaply than hitherto with the known methods and known devices.

The combination of ramming and cutting the soil increases the driving performance significantly and it can also be used in very hard soils and rock interspersed soils, which are no longer or only very poorly and laboriously worked with the previously common static [pushing and pulling] methods could be worked. This not only significantly increases the performance and thus the economic viability, 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 construction 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 expansion device, 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 cutting nozzles etc., is caused by the compressed air Supply device of the expander is operated like a one-direction earth ram with a cadence that can be determined by the control geometry of the control device belonging to the striking 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 from the cutting device of the cutting device under extremely high pressure and cut it up with it. This also allows rock inclusions to be cut and subsequently smashed 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 jacking 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 associated with purely static tension 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 (19)

Method for expanding a straight or curved pilot borehole and then pulling in a pipe with an expanding device, characterized in that the pilot borehole [10] strikes and cuts, and the soil is displaced displacing. A method according to claim 1, characterized in that a train is additionally exerted on the automatic device [1]. Method according to one of claims 1 or 2, characterized in that high-pressure cutting fluid is used to cut the soil. Method according to one of claims 1 or 2, characterized in that the cutting fluid which is under high pressure for cutting the soil is discharged indirectly or immediately before the current expansion area. Method according to one of claims 3 or 4, characterized in that the cutting fluid which is under high pressure for cutting the soil is discharged indirectly or immediately before and in the current expansion area. Method according to one of claims 3 - 5, characterized in that a part of the cutting fluid supplied for cutting the soil to reduce the Friction between the borehole wall and the pipe to be pulled in is used. Expanding device for carrying out the method according to claim 1 consisting of a cylindrical housing with a front expanding head and a drive device for forward movement in the ground as well as a device for connecting and pulling pipes into the expanded borehole, characterized in that the drive device has an impact device [2] for independent use Forward movement of the expander is, which has a striking body [5] impacting on the face inside the housing [3], the striking device [2] having an essentially cylindrical housing with a cylindrical housing length which is shorter than 4 times the housing diameter that the expanding head [4] is designed as a hollow head [4.1] for at least temporarily receiving a part of the striking device and that a cutting device [13] is provided which has means [15] for the discharge of cutting fluid at high pressure and in the area of the Au fweitkopfes [4] is arranged. Expansion device according to claim 7, characterized in that the means [15] of the cutting device [13] for the discharge of cutting fluid with high pressure are designed as at least one nozzle-shaped opening [15.1] at the free end of internal conduit channels [13.4]. Expanding device according to claim 8, characterized in that the cutting device [13] is arranged in front of the expanding head [4] and is connected to it. Expanding device according to claim 8, characterized in that the cutting device [13] is arranged integrated in the expanding head [4]. Expansion device according to claim 8 or 9 or 10, characterized in that the axis direction of each nozzle-shaped opening [15.1] points at least partially in the direction of advance of the borehole. Expansion device according to claim 8 or 9 or 10, characterized in that the axis direction of each nozzle-shaped opening [15.1] is at least partially opposite to the direction of advance of the borehole. Expanding device according to claim 8 or 9 or 10, characterized in that the axial directions of the nozzle-shaped opening (15.1) point partly approximately opposite to and partly approximately in the direction of advance of the borehole and partly radially to the borehole. Expander according to claim 8 or 9 or 10, characterized in that the expander head [4] is welded to the housing [3] of the impact device [2], the weld seam being arranged behind an impact point [4.2] on the face of the impact body [5]. Expander according to Claim 14, characterized in that the expander head [4] has means at its free end for connection to further appliances, in particular high-pressure lines for the cutting fluid. Expanding device according to claims 7-14, characterized in that at the rear end of the expanding device [1] at least one lubricating nozzle [16] is provided for the discharge of cutting fluid on the jacket side of the tube drawn in by the expanding device [1] for lubricating the pulling-in movement. Expanding device according to claims 7-15, characterized in that the essentially cylindrical housing is a waisted housing [3], with guiding rims [3.4] arranged on both housing ends and a waisted section [3.5] in between to facilitate cornering. Expanding device according to claims 7-16, characterized in that a pilot drilling device [14] is connected to the expanding device, a damping element [18] being arranged between the two. Expanding device according to claim 17, characterized in that supply lines for the pilot drilling device [14] can be connected to the expanding device [1].

Images