Flushing device, in particular for installation in a drill string

Abstract

In a flushing device, particularly for installation in a drill string designed for drilling boreholes into 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. A further aspect of the invention relates to a method for flushing soil with a flushing device according to the invention.

Description

[0001] The invention relates to a flushing device, in particular for installation in a drill string designed for drilling boreholes into the ground, wherein the flushing device is provided for installation behind a drill bit of the drill string. The invention further relates to a method for flushing soil.

[0002] Pipelines can be laid underground, for example, by digging trenches, laying the pipes in the trenches, and then backfilling the trenches with soil once the pipelines are complete. This type of earthwork is time-consuming, labor-intensive, and therefore costly. Particular problems arise when pipelines need to be laid beneath obstacles.

[0003] Trenchless pipe-laying methods include horizontal drilling techniques, such as horizontal directional drilling (HDD), which allow pipelines to be laid without excavating a trench. Starting from an entry point, a horizontal drilling rig can be used to create a borehole at an angle into the ground until the desired depth is reached, enabling the pipeline to be safely routed beneath an obstacle. With an HDD, a drill head is used to create a pilot bore towards the target point. The drill head can be bolted to a drill string, forming the drill string. The drill string can have a smaller diameter than the drill head, leaving an annular space between the drill string and the surrounding soil.Drilling fluid can be pumped through the drill string to the drill head, where it exits and flushes the soil loosened by the drill head through the annular space.

[0004] US Patent 4,583,603 A describes a drill string fitting for insertion into a drill string, comprising a body with a through axial bore. The body generally has cylindrical upper and lower sections and a widened cylindrical intermediate section. At least three cutouts for inserting removable fittings are formed at the upper end of the intermediate section, each with an upward-facing internal passage connecting the bore to a replaceable nozzle mounted at the upper end of the passage and having a diameter between the outer diameter of the intermediate section and that of the upper section of the body.

[0005] EP 0 494 408 A1 describes a method for widening a straight or curved pilot borehole and subsequently pulling in a pipe, in which the pilot borehole is widened by impact and cutting, as well as by displacing the surrounding soil. High-pressure cutting fluid is used to cut the soil. A widening device for carrying out the method comprises a cylindrical housing with a front widening head and a drive mechanism for forward movement in the soil, as well as a device for connecting and pulling pipes into the widened borehole. The drive mechanism is designed as an impact device, which has an impact element that strikes the end face inside the housing and has a cylindrical housing length that is shorter than four times the housing diameter.The expanding head for receiving part of the impact device is designed as a hollow head and can be connected to a cutting device which has means for the release of cutting fluid at high pressure, preferably cutting nozzles.

[0006] DE 10 2015 003157 A1 discloses a drill string element for installation in a drill string, particularly for horizontal or slant directional drilling (HDD or SDD), for creating a borehole along a drill path, especially for laying a pipeline, comprising a tubular base body with connecting elements on both sides for connecting the drill string element to the drill string. The drill string element has an interior space through which a drilling fluid can be transported for flushing the borehole and for removing drill cuttings loosened by a drill head connected to the drill string. At least one opening connected to the interior space is arranged in a wall of the base body, through which at least a portion of the drilling fluid flowing through the interior space enters an annular space between the borehole wall and the base body.Furthermore, at least one body is arranged on the outer wall above the opening, in which a flow channel is at least partially arranged. The flow channel has at least one flow path and is fluidically connected to the opening via an inlet opening. The flow channel has at least one outlet opening on its side facing away from the opening, and the clear cross-section of the opening and / or inlet opening is smaller or larger than the clear cross-section of the outlet opening.

[0007] The invention is based on the objective 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 enlargement of the borehole.

[0008] This problem is solved by a rinsing device having the features of claim 1 and by a method having the features of claim 10.

[0009] In a flushing device, particularly for installation in a drill string designed for creating boreholes in the ground, wherein the flushing device is intended for installation behind a drill head of the drill string, wherein the flushing device has a tubular base body, wherein the flushing device has at least one nozzle body for dispensing at least one fluid, wherein the base body has recesses for receiving the at least one nozzle body, wherein the at least one nozzle body is detachably connected to the base body, wherein the base body has an at least substantially cylindrical central section, wherein conically tapered areas adjoin the central section on both sides, it is essentially provided in the invention that the recesses are arranged on both sides of the central section in the conically tapered areas.The flushing device is designed for installation in a drill string, which may consist of a drill rod (composed of several drill sections) and at least one drill head, which may, for example, be a drill bit. The drill bit may be, for example, a pilot bit, in particular a roller bit. To avoid interfering with any 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 adjusted depending on the application. The flushing device has a base body with recesses, each of which can accommodate at least one nozzle body. In particular, the base body has several recesses, each preferably accommodating a nozzle body.The nozzle bodies are detachably mounted in the recesses, allowing for their interchangeability. For example, the nozzle bodies can be connected to their respective recesses by screw connections. Each nozzle body has at least one nozzle opening through which a fluid, particularly the drilling fluid, can be discharged into the annular space between the drill string and the surrounding soil. The fluid is guided through the tubular drill rods to the drill head and the flushing device. Thus, the drill string forms a fluid-conducting pipeline, at least in sections. For connection to the drill string, the flushing device has terminal fittings on both ends. These fittings can, for example, be threaded. The nozzle openings are fluid-conducting and connected to fluid openings in the recesses of the base body.The fluid passes through the drill string into the main body of the flushing device and through the fluid openings in the recesses of the main body to the nozzle openings of the nozzle bodies. If no nozzle body is installed in a recess, the respective fluid opening may be closed with a blanking plug. The nozzle opening determines a fixed spray angle. Thus, the fluid can be discharged through the nozzle bodies at a shallower or steeper angle to the longitudinal extent of the drill string, particularly to its longitudinal axis of symmetry. Specifically, 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.The nozzle bodies and the fluid they deliver allow the soil loosened by the drill bit to be flushed out of the borehole through the annular space. This is made possible, in particular, by the supporting nozzles, even over greater distances, especially exceeding 1,000 meters, without the flow of flushing fluid being interrupted. The central section of the base body is essentially hollow and cylindrical. The base body is essentially mirror-symmetrical. On both sides of the central section are conically tapered sections that reduce the diameter from that of the central section to a smaller diameter. These tapered sections form annular surfaces in which the recesses are arranged, at least partially. The nozzle bodies can thus be accommodated by the base body on both sides of the central section.This allows fluid flows in the direction of the drilling string's advance and in the opposite direction.

[0010] In a further development of the invention, the nozzle bodies each have at least one nozzle opening, and the nozzle bodies determine the fluid's spray angle. The nozzle bodies are detachably connected to the recesses of the base body. The nozzle bodies are thus interchangeable, allowing the use of different nozzle bodies with different fluid spray angles relative to the longitudinal extent of the drill string. For example, the fluid can be sprayed at a steep angle to the longitudinal extent of the base body, directing the fluid flow more towards the surrounding soil, or the fluid can be directed at a shallow angle along the annular space. Thus, depending on the application, the flushing device can be configured to either enlarge the borehole and therefore the annular space, or it can be designed to flush the excavated soil material through the annular space.

[0011] In one embodiment of the invention, the base body is rotationally symmetrical. The base body of the flushing device can, in particular, be rotationally symmetrical, for example, hollow cylindrical, so that the recesses for receiving the nozzle bodies can be arranged distributed along its 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 surrounding soil.

[0012] In one embodiment of the invention, the recesses are evenly distributed along the circumference of the base body. This distribution of the recesses, and thus of the nozzle bodies, enables the uniform generation of a fluid flow in the annular space surrounding the flushing device.

[0013] In one embodiment of the invention, the recesses are arranged in the tapered annular surfaces of the tapered areas and are laterally bounded by tapered side walls. The recesses are arranged in the tapered areas such that their longitudinal extent runs essentially parallel to the longitudinal extent of the base body. This means that each recess is bounded on two parallel sides by tapered side walls. Tapered webs are formed between the side walls of two adjacent recesses, forming the annular surface. The nozzle bodies received in the recesses can, in particular, be flush with the recesses so that they are flush with the circumference of the central part.

[0014] In one embodiment of the invention, the conical ring surfaces each have eight recesses. The conically tapered areas lateral to the central part can each have eight recesses, so that the base body has a total of 16 recesses for receiving nozzle bodies.

[0015] In one embodiment of the invention, the central section has a larger diameter than the other sections of the flushing device. These other sections of the flushing device can, for example, be connecting pieces for the drill string, allowing it to be integrated into the drill string. The diameter of the central section is preferably smaller than the diameter of the borehole created by the drill bit.

[0016] In one embodiment of the invention, nozzle bodies with different angles of attack can be accommodated in the recesses. Because different nozzle bodies with varying angles of attack of the nozzle openings can be accommodated in the recesses, the flushing device can be adapted to different applications. For example, nozzle bodies with steep angles of attack can be used to enlarge a borehole, while nozzle bodies with shallower angles of attack can be used to improve the return flow through the annular space by extending the base body longitudinally.

[0017] In one embodiment of the invention, the nozzle openings in a first annular surface are oriented essentially in the direction of advance of the drill string, and the nozzle openings of a second annular surface are oriented essentially opposite to the direction of advance of the drill string. The nozzle openings of the nozzle bodies in a first conical region, viewed from the drill head, can be oriented in the direction of advance of the drill string, while the nozzle openings arranged in a second conical region, located behind the central section from the drill head, can be oriented opposite to the direction of advance. The nozzle bodies arranged in the second conical region thus support a fluid flow through the annular space in the direction of the borehole's starting point.

[0018] Another aspect of the invention relates to a method for flushing soil with a flushing device according to the invention, wherein the fluid flow directed through the nozzles is directed both substantially in the direction of the drilling advance and substantially against the direction of the drilling advance. In particular, by directing the fluid flow against the direction of advance of the drill string, an optimized return flow of the drilling fluid is achieved. The flushing device according to the invention, with nozzle bodies received in the recesses of the base body, can be used for flushing soils. For example, when installed in a drill string with a drill bit, the flushing device can be used to assist a fluid flow, in particular a flow of drilling fluid, towards the entry side of the drill string. Thus, the flushing device transports the sediment loosened by the drill bit towards the entry opening.Furthermore, the drilling fluid system can be used in a borehole string to enlarge the diameter of the borehole, i.e., the annular space. For this purpose, nozzles with a large spray angle relative to the length of the borehole string can be selected. Enlarging the borehole allows for adjustment of the pressure conditions in the annular space; in particular, the annular pressure can be reduced, and the occurrence of blowouts minimized. A drilled borehole can also be sealed or cemented using the drilling fluid system by pumping 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 drilling fluid system can also be used to create artificial borehole collapses. By flushing with water, the filter cake on a borehole wall can be softened or...The rock is broken down, causing the borehole to become unstable. This can be achieved, for example, by injecting a large amount of drilling fluid or water under high pressure at a specific point. The resulting unstable caverns then tend to collapse.

[0019] Furthermore, the flushing device according to the invention makes it possible to flush out obstacles when used as a standalone tool and not integrated into a drill string. Obstacles located at least partially underground can be flushed out by means of a fluid flow using angled nozzles, without having to come into direct contact with the obstacles.

[0020] In a further development of the invention, a borehole is created using the method, wherein a substantially horizontal borehole is driven into the ground by means of at least one drilling device comprising a drill string and a drill bit, wherein a drilling fluid flow is generated through the drill bit, wherein the drilling device includes the flushing device, wherein at least one fluid is guided through the nozzles of the flushing device, thus generating a fluid flow, and wherein the fluid flow guided through the nozzles supports a return flow of drilling fluid in the annular space of the borehole. The drilling device for creating the borehole includes a flushing device according to the invention. During the creation of the borehole, a fluid is guided through the flushing device, the direction of the fluid flow being determined by the angle of attack of the nozzle openings of the nozzle bodies.Since the fluid flow can be directed both opposite to and in the direction of advance of the drill string, the generated fluid flow can support the return flow of the drilling fluid. In particular, the method for creating a borehole can be a drilling fluid method. Furthermore, the return flow of the drilling fluid can be stabilized by increasing the borehole diameter, thus enabling borehole lengths of over 1,000 meters. The use of the flushing system optimizes borehole cleaning, as the return flow of the drilling fluid is primarily generated by the flushing system and not by the fluid exiting the pilot drill bit. In a further development of the method, the diameter of the borehole is increased by the fluid flow directed through the nozzles.

[0021] The created borehole can be significantly enlarged by the additional flushing flow introduced by the flushing system and by adjusting the nozzle angles. Depending on the nozzle angle, the pumped flow rate, and the number and diameter of the nozzles, the area of ​​the borehole flushed by the system can be several times larger than the pilot borehole area. In particular, by enlarging the borehole, the annular pressure can be significantly reduced compared to conventional methods, thus minimizing the risk of blowouts.

[0022] In a further development of the method, the fluid flow directed through the nozzles flushes out obstacles that are at least partially underground. The fluid flow generated by the flushing device can flush out objects, such as obstacles that are at least partially underground. The angled nozzles generate a flushing flow with a sufficient radial range to clear obstacles without coming into direct contact with them.

[0023] The invention will now be explained in more detail with reference to an embodiment illustrated in the drawing. The schematic diagrams show: Fig. 1: a perspective view of the rinsing device according to the invention; Fig. 2: a side view of the rinsing device according to the invention. 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 Fig. 1 ; and Fig. 5: a drill string with built-in flushing device.

[0024] In Fig. 1 A flushing device 1 with a central section 2 and two connecting pieces 3 and 4 is shown in a perspective view. The central section 2 of the flushing device 1 is essentially hollow and cylindrical. Conically tapered sections 5 and 6 adjoin the central section 2. Recesses 7 are arranged in the conical sections 5 and 6, which are designed to receive nozzle bodies 8. The flushing device 1 can be installed in the pipe string of a drill string 14 via the connecting pieces 3 and 4. The nozzle bodies 8 have nozzle openings 9, each of which has a fixed angle of attack relative to the longitudinal extent of the base body 10 of the flushing device 1. A fluid flow can be generated through the nozzle openings 9, the direction of which depends 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 interchangeable and nozzle bodies 8 with different angles of attack of the nozzle opening 9 can also be installed.

[0025] In Fig. 2 is a side view of the flushing device 1 according to Fig. 1 Identical components are designated with the same reference numerals. The conical sections 5 and 6 can each, for example, form 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 section 5 can be directed in the direction of the advance movement of the borehole, while the nozzle bodies in the conical section 6 generate a fluid flow opposite to the direction of movement. The fluid flow through the nozzle bodies 8 of the first conical section 5 is thus directed towards the drill head 15, while the fluid flow of the nozzle bodies 8 in the conical section 6 is directed away from the drill head 15.

[0026] In Fig. 3 is a cross-section of the flushing device 1 according to Fig. 2 The cutouts 7 are shown along section A - A. The recesses are evenly distributed along the circumference of the base body 10.

[0027] 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 inside, through which a flushing fluid can be directed towards 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 enter the nozzle bodies 8 and pass through the nozzle openings 9.

[0028] In Fig. 5 The schematic diagram shows the installation of a flushing device 1 in a drill string 14 with a drill head 15. 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 affect the function of the drill head 15, for example, a control probe.

Claims

1. A flushing device (1) for installation in a drill string (14), which is designed to introduce boreholes in the ground, wherein the flushing device (1) is intended for installation behind a drill head (15) of a drill string (14), wherein the flushing device (1) comprises a base body (10) which is cylindrical at least in sections, wherein the flushing device (1) comprises at least one nozzle body (8) for dispensing at least one fluid, wherein the base body (10) has recesses (7) for receiving the at least one nozzle body (8), wherein the at least one nozzle body (8) is connected detachably to the base body (10), wherein the base body (10) comprises an at least essentially cylindrical central part (2), and wherein conically tapered regions (5, 6) are then arranged on both sides of the central part (2), characterised in that the recesses (7) are arranged on both sides of the central part (2) in the annular surfaces of the conically tapered regions (5, 6).

2. The flushing device (1) according to claim 1, characterised 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 body (8).

3. The flushing device (1) according to any one of claims 1 or 2, characterised in that the base body (10) is constructed rotationally symmetrical.

4. The flushing device (1) according to any one of claims 1 to 3, characterised in that the recesses (7) are arranged distributed uniformly along the circumference of the base body (10).

5. The flushing device (1) according to any one of claims 1 to 4, characterised 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 bordered laterally by conically tapered side walls.

6. The flushing device (1) according to any one of claims 1 to 5, characterised in that the conical annular surfaces each have eight recesses (7).

7. The flushing device (1) according to any one of claims 1 to 6, characterised in that the central part (10) has a larger diameter than the other regions of the flushing device (1).

8. The flushing device (1) according to any one of claims 1 to 7, characterised in that nozzle bodies (8) with different angles of attack of the nozzle openings (9) can be received in the recesses (7).

9. The flushing device (1) according to any one of claims 1 to 8, characterised in that the nozzle openings (9) in a first annular surface are directed essentially in the direction of advance of the drill string (14) and that the nozzle openings (9) in a second annular surface are directed essentially against the direction of advance of the drill string (14).

10. A method for flushing earth with a flushing device (1) according to any one of the preceding claims, wherein the fluid flow conveyed through the nozzles (8) is conveyed both essentially in the direction of the drilling advance and also essentially against the direction of the drilling advance.

11. The method according to claim 10, characterised in that a borehole is created by means of the method, wherein an essentially horizontal borehole is introduced into the ground by means of at least one drilling device comprising a drill rod and a drill head (15), wherein a drilling fluid flow is generated through the drill head (15), wherein the drilling device comprises the flushing device (1), wherein at least one fluid is conveyed through the nozzles (8) of the flushing device (1) and a fluid flow is thus generated, wherein a backflow of a drilling fluid flow in the annular space of the borehole is supported by the fluid flow conveyed through the nozzles (8).

12. The method according to claim 11, characterised in that the diameter of the borehole is increased by the fluid flow conveyed through the nozzles (8).

13. The method according to claim 10, characterised in that an object located at least partially underground is flushed out by the fluid flow conveyed through the nozzles (8).

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