EP4368809A1 - Flushing device, in particular for installation in a drill string - Google Patents

Abstract

In a flushing device, in particular for installation in a drill string which is designed to create boreholes in the ground, wherein the flushing device is intended for installation behind a drill head of the drill string, it is provided as part of the invention that the flushing device has a tubular base body, that the flushing device has at least one nozzle body for dispensing at least one fluid, that the base body has recesses for receiving the at least one nozzle body, and that the at least one nozzle body is detachably connected to the base body. Another aspect of the invention relates to a method for flushing soil with a flushing device according to the invention.

Description

The invention relates to a flushing device, in particular for installation in a drill string which is designed to create boreholes in the ground, wherein the flushing device is intended for installation behind a drill bit of the drill string. The invention further relates to a method for flushing ground.

For example, pipes can be laid underground by digging trenches, laying the pipes in the trenches and, once the pipes are finished, filling the trenches with soil. This earthwork is time-consuming, labor-intensive and therefore costly. Particular problems arise with this type of earthwork when pipes are to be laid beneath obstacles.

Horizontal drilling methods, such as horizontal directional drilling, are known as trenchless installation methods, with which a pipeline can be laid without having to dig a trench. For example, starting from an entry point, i.e. from a starting point, a borehole can be initially drilled diagonally into the ground using a horizontal drilling device until the desired depth is reached in order to guide the pipeline safely beneath an obstacle. With a horizontal directional drilling system, for example, a pilot hole is drilled in the direction of the target point using a drill head. The drill head can be screwed to a drill rod and thus form the drill string. The drill rod can have a smaller diameter than the drill head, so that an annular space is left between the drill rod and the soil. A drilling fluid can be pumped through the rod to the drill head, where it exits and flushes the soil loosened by the drill head through the annular space.

The invention is based on the object of proposing a device with which the return flow of the drilling fluid through the annular space of the borehole can be improved. Furthermore, the device should contribute to the expansion of the borehole.

This object is achieved with a flushing device having the features of patent claim 1 and with a method having the features of patent claim 11.

In a flushing device, in particular for installation in a drill string that is designed to create boreholes in the ground, wherein the flushing device is intended for installation behind a drill head of the drill string, it is essential to the invention that the flushing device has a tubular base body, that the flushing device has at least one nozzle body for dispensing at least one fluid, that the base body has recesses for receiving the at least one nozzle body, and that the at least one nozzle body is detachably connected to the base body. The flushing device is intended for installation in a drill string, wherein the drill string can consist of a drill rod, which can be composed of several drill rods, and at least one drill head, which can be formed by a drill bit, for example. The drill bit can be a pilot bit, in particular a roller bit, for example. In order to avoid influencing a control probe that may be installed in the drill head, the flushing device is installed in the drill string at a distance from the drill head. The distance between the flushing device and the drill head can be The flushing device has a base body in which recesses are arranged, in each of which at least one nozzle body can be accommodated. In particular, the base body has several recesses, with a nozzle body preferably being accommodated in each recess. The nozzle bodies are each detachably accommodated in the recesses so that the nozzle bodies are exchangeable. For example, the nozzle bodies can be connected to the respective recess by screw connections. The nozzle bodies each have at least one nozzle opening through which a fluid, in particular the drilling fluid solution, can be released into the annular space between the drill rod and the ground. The fluid is guided through the tubular drill rods to the drill head and the flushing device. A fluid-conducting pipeline is thus formed through the drill rod, at least in sections. For connection to the drill rod, the flushing device has connectors arranged at the end on both sides for connection to the drill rod. For example, the connectors can have threads. The nozzle openings are connected in a fluid-conducting manner to fluid openings in the recesses of the base body. The fluid passes through the drill rod into the base body of the flushing device and through the fluid openings in the recesses of the base body to the nozzle openings of the nozzle bodies. If no nozzle body is accommodated in a recess, the respective fluid opening can be closed with a blind plug. A fixed beam angle is specified by the nozzle opening. The fluid can thus be emitted through the nozzle bodies at a flatter or steeper angle to the longitudinal extension of the drill rod, in particular to its longitudinal axis of symmetry. In particular, the fluid flow through the nozzle bodies can also be directed essentially in the direction of advance or against the advance direction of the drill string. The advance direction is the direction in which the drill string is moved through the ground to create the borehole. Through the nozzle bodies and the fluid emitted by the nozzle bodies the soil loosened by a drill bit can be flushed out of the borehole through the annular space. This is possible in particular over a longer distance, in particular over 1,000 meters, thanks to the supporting nozzles, without the flushing flow coming to a standstill.

In a development of the invention, the nozzle bodies each have at least one nozzle opening and the jet angle of the fluid is predetermined by the nozzle bodies. The nozzle bodies are detachably connected to the recesses in the base body. The nozzle bodies are thus interchangeable, so that different nozzle bodies with different jet angles of the fluid in relation to the longitudinal extension of the drill string can be used. For example, the fluid can be jetted at a steep angle to the longitudinal extension of the base body so that the fluid flow is directed more in the direction of the surrounding soil, or the fluid can be guided at a shallow angle along the annular space. Depending on the application, the flushing device can thus be set up to expand the borehole and thus the annular space more, or the flushing device can be more geared towards flushing the flushing flow of the loosened earth material through the annular space.

In one embodiment of the invention, the base body is rotationally symmetrical. The base body of the flushing device can be rotationally symmetrical, for example, as a hollow cylinder, so that the recesses for receiving the nozzle bodies can be distributed along the circumference. This allows the fluid flow to be generated along the entire circumference of the base body in the annular space between the drill string and the ground.

In one embodiment of the invention, the recesses are evenly distributed along the circumference of the base body. By distributing the Recesses and thus the nozzle body enable a uniform generation of a fluid flow in the annular space around the flushing device. In one embodiment of the invention, the base body has an at least essentially cylindrical middle section, conically tapered areas adjoin the middle section on both sides and the recesses are arranged on both sides of the middle section in the conically tapered areas. The middle section of the base body is essentially hollow-cylindrical. The base body is constructed essentially mirror-symmetrically. Conically tapered areas adjoin the middle section on both sides, which reduce the diameter of the middle section to a smaller diameter. The conically tapered areas form ring surfaces in which the recesses are arranged at least in sections. The nozzle bodies can thus be accommodated by the base body on both sides of the middle section. This enables fluid flows in the direction of the advancement direction of the drill string and in the opposite direction.

In one embodiment of the invention, the recesses are arranged in the tapered ring surfaces of the tapered regions and the recesses are laterally delimited by tapered side walls. The recesses are arranged in the tapered regions in such a way that their longitudinal extension runs essentially parallel to the longitudinal extension of the base body. As a result, the recesses are each delimited on two parallel sides by tapered side walls. Tapered webs are formed between the side walls of two adjacent recesses, which form the ring surface. The nozzle bodies accommodated in the recesses can in particular be accommodated flush in the recesses so that they are flush with the circumference of the central part.

In one embodiment of the invention, the conical ring surfaces each have eight recesses. The tapered areas on the sides of the central part can each have eight recesses, so that the base body has a total of 16 recesses for receiving nozzle bodies.

In one embodiment of the invention, the middle part has a larger diameter than the other areas of the flushing device. The other areas of the flushing device can be, for example, connecting pieces for the rods of the drill string, so that it can be installed in the drill string. The diameter of the middle part is preferably smaller than the diameter of the hole created by the drill bit.

In one embodiment of the invention, nozzle bodies with different angles of attack can be accommodated in the recesses. Because different nozzle bodies with different angles of attack of the nozzle openings can be accommodated in the recesses, the flushing device can be adapted to different purposes. For example, nozzle bodies with steep angles of attack can be used to enlarge a borehole, while nozzle bodies with flatter angles of attack can be used for the longitudinal extension of the base body to improve the return flow through the annular space.

In one embodiment of the invention, the nozzle openings in a first ring surface are directed essentially in the direction of the advance direction of the drill string and the nozzle openings in a second ring surface are directed essentially against the advance direction of the drill string. The nozzle openings of the nozzle bodies in a first conical region, as seen from the drill head, can be directed in the direction of the advance direction of the drill string, while those in a second conical region, as seen from the drill head The nozzle openings arranged in the conical area behind the central part can be directed against the direction of advance. The nozzle bodies arranged in the second conical area thus support a fluid flow through the annular space in the direction of the starting point of the bore.

A further aspect of the invention relates to a method for flushing soil with a flushing device. The flushing device according to the invention with nozzle bodies accommodated in the recesses of the base body can be used for flushing soil. For example, when the flushing device is installed in a drill string with a drill bit, it can be used to support a fluid flow, in particular a flow of drilling fluid, in the direction of the inlet side of the drill string. The flushing device therefore transports the sediment loosened by the drill bit in the direction of the inlet opening. Furthermore, the flushing device can be used in a drill string to enlarge the diameter of the borehole, i.e. the annular space. For this purpose, nozzles with a large beam angle to the longitudinal extent of the drill string can be selected. By enlarging the borehole, it is possible to adjust the pressure conditions in the annular space, in particular the annular space pressure can be reduced and the occurrence of blowouts can be minimized. Using the flushing device, a drill hole can also be dammed or cemented by pumping in the appropriate fluids. This is particularly advantageous due to the modular design with interchangeable nozzle bodies, as the nozzle bodies can be easily cleaned or replaced. The flushing device can also be used to cause artificial borehole collapses. By flushing with water, the filter cake on a borehole wall can be softened or dissolved, making the borehole unstable. For example, a high input of drilling fluid or water under high pressure can be used at certain points. The resulting unstable caverns then tend to collapse.

In addition, the flushing device according to the invention makes it possible to flush obstacles when it is used as a single tool and not installed in a drill string. Obstacles that are at least partially located underground can be flushed out by means of a fluid flushing stream through nozzles that are set up, without having to come into direct contact with the obstacles.

In a further development of the invention, a borehole is created by means of the method, wherein a substantially horizontal borehole is made in the ground by means of at least one drilling device having a drill rod and a drill bit, wherein a drilling fluid flow is generated by the drill bit, wherein the drilling device has the flushing device, wherein at least one fluid is passed through the nozzles of the flushing device and thus a fluid flow is generated, wherein a backflow of a drilling fluid flow in the annular space of the borehole is supported by the fluid flow passed through the nozzles. The drilling device for creating the borehole has a flushing device according to the invention. When creating the borehole, a fluid is passed through the flushing device, wherein the direction of the fluid flow is predetermined by the angle of attack of the nozzle openings of the nozzle bodies. Since the fluid flow can be directed both opposite to the advance direction of the drill string and in the direction of the advance direction of the drill string, the generated fluid flow can support the backflow of the drilling fluid. In particular, the method for creating a borehole can be a drilling fluid method. In addition, the drilling fluid return flow can be stabilized by enlarging the borehole, so that bore lengths of more than 1,000 meters can be achieved. In particular, the use of the flushing device optimizes the cleaning of the borehole, since the return flow of the drilling fluid flow is mainly generated by the flushing device and not by the flushing fluid emerging from the pilot bit. In a In a further development of the process, the diameter of the borehole is increased by the fluid flow passed through the nozzles.

The borehole created can be significantly enlarged by the additional flushing flow introduced by the flushing device and by the angle of attack of the nozzles. Depending on the angle of attack of the nozzles on the flushing device, the pumped volume flow and the number of nozzles installed on the flushing device and their diameter, the borehole area flushed with the flushing device can be several times larger than the pilot drilling area. In particular, by enlarging the borehole, the annular space pressure can be significantly reduced compared to conventional methods and thus the risk of blowouts can be minimized.

In one embodiment of the method, the fluid flow guided through the nozzles is guided both essentially in the direction of the drilling advance and essentially against the direction of the drilling advance. In particular, by guiding the fluid flow against the direction of advance of the drill string, an optimized return flow of the drilling fluid is achieved.

In a further development of the method, the fluid flow directed through the nozzles flushes away obstacles that are at least partially underground. The fluid flow generated by the flushing device can flush away objects, for example obstacles that are at least partially underground. The nozzles in position generate a flushing flow with a corresponding radial range that is able to flush away obstacles without coming into direct contact with them.

Fig. 1:

eine perspektivische Darstellung der erfindungsgemäßen Spülvorrichtung;

Fig. 2:

eine Seitenansicht der Spülvorrichtung gemäß Fig. 1;

Fig. 3:

einen Querschnitt der Spülvorrichtung gemäß Fig. 1;

Fig. 4:

einen Längsschnitt einer erfindungsgemäßen Spülvorrichtung gemäß Fig. 1; und

Fig. 5:

einen Bohrstrang mit eingebauter Spülvorrichtung.

The invention is explained in more detail below using an embodiment shown in the drawing. The schematic representations show:

Fig.1:

a perspective view of the rinsing device according to the invention;

Fig. 2:

a side view of the flushing device according to Fig.1 ;

Fig. 3:

a cross section of the flushing device according to Fig.1 ;

Fig.4:

a longitudinal section of a flushing device according to the invention according to Fig.1 ; and

Fig.5:

a drill string with built-in flushing device.

In Fig.1 a flushing device 1 with a central part 2 and two connecting pieces 3 and 4 is shown in a perspective view. The central part 2 of the flushing device 1 is essentially hollow-cylindrical. Conically tapered areas 5, 6 adjoin the central part 2. Recesses 7 are arranged in the conical areas 5, 6, which are designed to accommodate nozzle bodies 8. The flushing device 1 can be installed in the pipe rod of a drill string 14 using the connecting pieces 3, 4. The nozzle bodies 8 have nozzle openings 9, each of which has a fixed angle of attack to the longitudinal extension of the base body 10 of the flushing device 1. A fluid flow can be generated through the nozzle openings 9, which is directed depending on the angle of attack of the nozzle openings 9. The nozzle openings 9 are connected to the base body 10 via screw connections 11, so that the nozzle bodies 8 are exchangeable and thus nozzle bodies 8 with other angles of attack of the nozzle opening 9 can also be installed.

In Fig.2 is a side view of the flushing device 1 according to Fig.1 Identical components are provided with the same reference numerals. The conical regions 5, 6 can each, for example, span an angle of 160° with the longitudinal axis of symmetry of the base body 10. For example, the nozzle openings 9 of the nozzle bodies 8 of a first conical region 5 can be directed in the direction of the advance movement of the drilling passage, while the nozzle bodies in the conical region 6 generate a fluid flow opposite to the direction of movement. The fluid flow through the nozzle bodies 8 of the first conical region 5 is thus directed in the direction of the drill head 15, the fluid flow of the nozzle bodies 8 in the conical region 6 is directed away from the drill head 15.

In Fig.3 is a cross section of the flushing device 1 according to Fig.2 along the section A - A. The recesses 7 are evenly distributed along the circumference of the base body 10.

In Fig.4 is a longitudinal section at position B - B of the base body 10 according to Fig.2 The base body 10 has a continuous pipe 12 in its interior, through which a flushing fluid can be guided in the direction of the drill head 15. In the area of the recesses 7, the base body 10 has fluid openings 13 through which the fluid to be pumped can reach the nozzle bodies 8 and through the nozzle openings 9. In Fig.5 The installation of a flushing device 1 in a drill string 14 with a drill head 15 is shown schematically. The flushing device 1 is arranged at a distance from the drill head 15, which can be designed as a drill bit, in order not to influence the function of the drill head 15, for example a control probe.

Reference number list:

1

Flushing device

2

Middle part

3

Connector

4

Connector

5

conical area

6

conical area

7

Recess

8th

Nozzle body

9

Nozzle opening

10

Base body

11

Screw connection

12

Pipeline

13

Fluid opening

14

Drill string

15

Drill head

Claims (15)

Flushing device (1), in particular for installation in a drill string (14) which is designed to create boreholes in the ground, wherein the flushing device (1) is intended for installation behind a drill head (15) of the drill string (14),
characterized, that the flushing device (1) has a base body (10) which is at least partially cylindrical, that the flushing device (1) has at least one nozzle body (8) for dispensing at least one fluid, that the base body (10) has recesses (7) for receiving the at least one nozzle body (8), and that the at least one nozzle body (8) is detachably connected to the base body (10). Flushing device (1) according to claim 1, characterized in that the nozzle bodies (8) each have at least one nozzle opening (9) and that a jet angle of the fluid is predetermined by the nozzle bodies (8). Flushing device (1) according to one of claims 1 or 2, characterized in that the base body (10) is constructed rotationally symmetrically. Flushing device (1) according to one of claims 1 to 3, characterized in that the recesses (7) are evenly distributed along the circumference of the base body (10). Flushing device (1) according to one of claims 1 to 4, characterized in that the base body (10) has an at least substantially cylindrical central part (2) that is connected to the central part (2) on both sides subsequently tapered regions (5, 6) are arranged and that the recesses (7) are arranged on both sides of the central part (2) in the annular surfaces of the tapered regions (5, 6). Flushing device (1) according to one of claims 1 to 5, characterized in that the recesses (7) are arranged in the conically tapered annular surfaces of the conically tapered regions (5, 6) and that the recesses (7) are laterally delimited by conically tapered side walls. Flushing device (1) according to one of claims 1 to 6, characterized in that the conical annular surfaces each have eight recesses (7). Flushing device (1) according to one of claims 5 to 7, characterized in that the central part (10) has a larger diameter than the other regions of the flushing device (1). Flushing device (1) according to one of claims 1 to 8, characterized in that nozzle bodies (8) with different angles of attack of the nozzle openings (9) can be accommodated in the recesses (7). Flushing device (1) according to one of claims 1 to 9, characterized in that the nozzle openings (9) in a first annular surface are directed substantially in the direction of the advance direction of the drill string (14) and that the nozzle openings (9) in a second annular surface are directed substantially opposite to the advance direction of the drill string (14). Method for flushing soil with a flushing device (1) according to one of the preceding claims. Method according to claim 11, characterized in that a borehole is created by means of the method, wherein a substantially horizontal borehole is introduced into the ground by means of at least one drilling device having a drill rod and a drill head (15), wherein a drilling fluid flow is generated through the drill head (15), wherein the drilling device has the flushing device (1), wherein at least one fluid is passed through the nozzles (8) of the flushing device (1) and thus a fluid flow is generated, wherein a backflow of a drilling fluid flow in the annular space of the borehole is supported by the fluid flow passed through the nozzles (8). Method according to claim 12, characterized in that the diameter of the borehole is increased by the fluid flow passed through the nozzles (8). Method according to one of claims 12 or 13, characterized in that the fluid flow guided through the nozzles (8) is guided both substantially in the direction of the drilling advance and substantially against the direction of the drilling advance. Method according to claim 11, characterized in that an object located at least partially underground is flushed out by the fluid flow conducted through the nozzles (8).

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