EP3271541A1

EP3271541A1 - Drill string element

Info

Publication number: EP3271541A1
Application number: EP16708083.7A
Authority: EP
Inventors: Tobias GERHARDT; Michael LUBBERGER; Tobias Engel
Original assignee: Herrenknecht AG
Current assignee: Herrenknecht AG
Priority date: 2015-03-15
Filing date: 2016-03-04
Publication date: 2018-01-24
Anticipated expiration: 2036-03-04
Also published as: AU2016232638B2; RU2696692C2; AU2016232638A1; CA2979903C; US20180245413A1; WO2016146241A1; RU2017134850A; RU2017134850A3; CN208416449U; DE102015003157A1; US10941624B2; EP3271541B1; CA2979903A1

Abstract

The invention relates to a drill string element for installing in a drill string, in particular for horizontal or slant directional drilling (HDD or SDD), for creating a borehole (100) along a drilling route, in particular for laying a pipeline, comprising a tubular main body (11) having connecting elements (13, 15) at both ends for connecting the drill string element (10) to the drill string, wherein the drill string element (10) has an interior (22), through which a flushing medium for flushing the borehole (100) and transporting away cuttings loosened by a drill head connected to the drill string can be transported, having at least one opening (23) in a wall (16) of the main body (11), which opening is connected to the interior (22) and through which opening at least part of the flushing medium flowing through the interior enters an annular space (102) between the borehole wall (103) and the main body (11), characterized in that at least one body (17) is arranged on the outer wall (16) over the opening (23), in which at least one body a flow channel (24) is at least partially arranged, that the flow channel (24) has at least one flow path and is fluidically connected to the opening (23) by means of an inlet opening (25), that the flow channel (24) has at least one outlet opening (28) on the side of the flow channel (24) facing away from the opening (23), and that the clear cross-section of the opening (23) and/or inlet opening (25) is smaller or larger than the clear cross-section of the outlet opening (28).

Description

Drilling string description

The invention relates to a drill string element for installation in a drill string, in particular for horizontal or slant directional drilling (HDD or SDD), for creating a borehole along a drill pipe, in particular for laying a pipeline, with a tubular base body with two-sided connecting elements for connecting the Bohrstrangelements with the drill string, wherein the Bohrstrangelement has an interior through which a flushing medium for flushing the borehole and the removal of dissolved by a drill string connected to the drill bit can be transported, with at least one connected to the interior opening in a wall of the body through which at least a portion of the flushing medium flowing through the interior passes into an annular space between the borehole wall and the base body.

A drilling and laying method (horizontal directional drilling) is known from EP 0 360 321, in which a pilot hole with a drill head and a drill string from a starting point to a destination point is created for the trenchless laying of a pipeline under an obstacle along a predetermined drilling line becomes. By rotating the drill string, the drill head is driven. Subsequently, a reamer is attached to the pilot drill string at the target side, which is connected to the pipeline to be laid. The reamer is driven by turning the drill string. An advancement of the scraper while pulling in the pipeline takes place by pulling out the pilot drill string. During the pilot drilling with the HDD method, the pilot drill head is pushed along the planned route along the lines using boring bars. A drilling suspension is made by means of a through the drill pipe leading opening to the pilot drill head pumped. There, the cuttings mined by the pilot drill head mix with the drilling suspension. This suspension then flows with the cuttings through the drilled hole back to the starting point or entry point of the hole. Since the diameter of the drill head is not substantially larger than the outer diameter of the drill rods, there is an annular space between the drill hole and the drill rod. In this annulus, a flow forms, with which the cuttings from the well is transported.

Due to the shape of the flow channel in the annulus, there are zones in which the flow velocity is close to zero, in these zones entrained cuttings deposited, a so-called cuttings bed is formed. The result of these deposits is an increased torque of the rotating drill string due to friction against the cuttings bed on the bottom of the borehole. In addition, the free flow cross-section decreases, the flow rate increases and thereby generates higher pressure losses during the return flow to the start of the bore. These pressure losses must be compensated by the mud pump, which leads to an increased pressure level at the exit of the drilling suspension at the pilot drill head. The higher flushing pressure at the outlet of the flushing at the drill head, in turn, depending on the upcoming mountains or its nature lead to a breakup of the mountains. This has the consequence that undefined flushing paths can usually arise perpendicular to the horizontal drilling axis directly to the surface, at which then the drilling fluid exits in an uncontrolled manner. In addition to the environmental aspect of an undefined flushing exit, drilling must also be interrupted, as a controlled discharge of the cuttings is no longer possible. A so-called purge blower can be repaired consuming only by additions additives in the drilling fluid or cementing the blower.

In practice, pre-critical mud pressures are usually calculated by superimposing existing geological data with a pressure calculation. The maximum values must not be exceeded. Pressure sensors behind the drill head allow the pressures to be measured and monitored. The object of the invention is to provide a drill string element and a drill string with the same, with which it is possible to keep the pressure in the annulus below the calculated limits or to keep the pressures prevailing in the annulus or drill string as small as possible, For example, it is possible to bring deposited drill cuttings back into the flow or to prevent settling of the drill cuttings.

The object of the invention is achieved according to a first solution in terms of Bohrstrangelements characterized in that on the outer wall over the opening at least one body is arranged in which at least partially a flow channel is arranged, that the flow channel has at least one flow path and fluidically with the opening via a Is connected inlet opening, that the flow channel on its side facing away from the opening side at least one outlet opening, and that the clear cross section of the opening and / or inlet opening is smaller or larger than the clear cross section of the outlet opening.

The provision of two different clear cross sections, in which the clear cross section of the opening and / or inlet opening is smaller than the clear cross section of the outlet opening, makes it possible in a particularly simple manner to provide a low pressure level at the nozzle exit. This ensures a lower flow velocity of the flushing medium at the outlet. The exit of the flushing medium is characterized less aggressive. At a high pressure level in the interior of the drill string and thus at the nozzle outlet, there is the danger that the borehole will be widened by the emerging flushing medium. It has been shown so unexpectedly that it is possible in a particularly simple manner, gently introduce the exiting rinse medium in the annulus. The provision of two different clear cross sections, in which the clear cross section of the opening and / or inlet opening is greater than the clear cross section of the outlet opening, makes it possible in a particularly simple manner to provide a higher pressure level at the nozzle outlet. This ensures a greater flow velocity of the flushing medium at the outlet. The exit of the flushing medium is thus more aggressive. This leaves In particular, when consciously selectively cuttings to be whirled up, at the same time the mountains in which the borehole is created or the rock of the borehole wall is such that at a high pressure level in the interior of the drill string and thus at the nozzle exit there is no risk that the borehole is expanded by the exiting flushing medium.

Another teaching of the invention provides that the clear cross section of the opening, the inlet opening and / or the outlet opening is adjustable. As a result, the desired parameters of the flushing medium are particularly easy einregelbar / adjustable.

A further teaching of the invention provides that in the opening, the inlet opening, within the flow channel and / or in the outlet opening at least one nozzle and / or aperture is arranged, wherein preferably at least one nozzle and / or aperture is made changeable. By means of a nozzle / aperture, the desired delivery parameters can be provided particularly easily. By changing the nozzle / nozzles, the desired parameters at the operating point of the Bohrstrangelements can be easily adjusted. As a result, different pressure levels within the drill string as a function of the drilling length are compensated in a particularly simple manner.

Another teaching of the invention provides that the outlet opening is arranged in a rear side surface of the body. The outlet opening is advantageously arranged on the rear side surface in such a way that the drilling suspension emerging at the outlet opening, which was received on the body by a receiving and transporting surface and leaves it at the rear end 20, is carried along by the drilling suspension emerging there and thus the general Flow of the drilling suspension in the annular space 102 is fed back and transported accordingly in the flow direction B from the well 100 addition.

Another teaching of the invention provides that the outlet opening is arranged substantially axially to the central axis of the Bohrstrangelements. As a result, the flushing medium is discharged along the drill string, which leads to a movement of the cuttings, especially if it has settled. Furthermore, a widening of the borehole is avoided by direct exposure of the discharged flushing medium to the borehole wall.

Another teaching of the invention provides that the at least one body, preferably one body, extends on the base body, so that the outer radius of the base body is enlarged in sections and an eccentric is present, through which the drill string can be temporarily raised during drilling. The eccentric drill string element causes the drill string to lift each revolution. Lifting reduces the flow area at the top of the well, causing the mud to flow along the bottom of the well. As a result, deposited cuttings are returned to the drilling fluid.

A further teaching of the invention provides that on the body, a side surface is provided, which is designed as a receiving and transport surface for deposited on a bottom of the well cuttings, wherein side surface is preferably executed helically with respect to the borehole axis. As a result, the remote cuttings are picked up and returned to the drilling fluid.

A further teaching of the invention provides that in the body above the opening and / or the inlet opening an access opening is arranged, in which a blind flange is preferably provided as a closure element. This makes it possible in a particularly simple manner changing the nozzle / aperture or make the same setting.

The object of the invention is achieved according to a further solution in terms of Bohrstrangelements in that on the outer wall at least one body is arranged, which extends on the base body, so that the outer radius of the base body is enlarged in sections and an eccentric is present, through which the drill string during drilling is temporarily raised with respect to the bottom of the wellbore. The eccentric drill string element causes a lifting of the Drill string. Lifting reduces the flow area at the top of the well, causing the mud to flow along the bottom of the well. As a result, deposited drill cuttings are again flushed around by the drilling fluid medium and are thereby returned to the drilling fluid.

A further teaching of the invention provides that the at least one body is exactly one or two bodies, preferably opposite one another. A further teaching of the invention provides that at least one opening connected to the interior is provided in a wall of the main body, through which at least a portion of the flushing medium flowing through the interior enters an annular space between the borehole wall and the base body, that above the opening of the body is arranged, in which at least partially a flow channel is arranged, that the flow channel has at least one flow path and fluidly connected to the opening via an inlet opening, that the flow channel on its side facing away from the opening at least one outlet opening, and that the clear cross section of Opening and / or inlet opening is smaller than the clear cross section of the outlet opening.

Another teaching of the invention provides that the clear cross section of the opening, the inlet opening and / or the outlet opening is adjustable. A further teaching of the invention provides that in the opening, the inlet opening, within the flow channel and / or in the outlet opening at least one nozzle and / or aperture is arranged, wherein preferably at least one nozzle and / or aperture is made changeable. Another teaching of the invention provides that the outlet opening is arranged substantially axially to the central axis of the Bohrstrangelements. A further teaching of the invention provides that on the body, a side surface is provided, which is designed as a receiving and transport surface for deposited on a bottom of the well cuttings, wherein side surface is preferably executed helically with respect to the borehole axis. In addition, it should be added that the expression "and / or" is understood to mean both "and" and "as well as" or "linking of the corresponding features. The solutions of the invention with reference to a preferred embodiment in conjunction with another drawing will be described in more detail.

Show

1 is a first perspective view of a Bohrstrangelements invention,

2 is a side view of FIG. 1,

3 is a perspective view of the underside to Fig. 1,

5 shows a sectional view of a drill string element according to the invention according to FIG. 1, cut as indicated in FIG. 4, FIG.

Fig. 6 is a perspective view of a Bohrstrangelements invention in a hole shown cut, and

7 shows a diagram of the pressure losses in the annular space as a function of the volume flow or the length of the bore.

FIGS. 1 to 6 show a drill string element 10 according to the invention with a base body 11 which is tubular. The base body 1 1 has at its front end 12 a male connecting element 13 and at its rear end 14 a female connecting element 15, which are each provided with corresponding thread (not shown). On the outer wall 16 of the base body 1 1, a body 17 is arranged, which is designed helically. In the preferred embodiment, the body 17 is welded onto the base body 11. However, it is also possible to arrange this by other, known in the art connection types on the base body 1 1. The body 17 has on a side surface 18 on a receiving and transporting surface 19, with the rotation of the drill string (rotation direction A) and thus also during the rotation of the Bohrstrangelements 10, which on a sole 101 of a borehole 100 in an annular space 102 between the outer wall 16 of the base body 11 and a borehole wall 103 cuttings (not shown) received by the receiving and transporting surface 19 of the bottom hole 101 and along the receiving and transporting surface 19 during rotation of the boring bar element 10 from the sole

101 is moved away until the cuttings have arrived at the rear end 20 of the receiving and transporting surface 19, where the cuttings leaving the receiving and transporting surface 19 and again the flowing Bohrbülungsmedium in the direction of flow B is supplied from the borehole 100 through the annulus

102 to be transported. The inclusion of the cuttings occurs at the top 21 of the receiving and transport surface 19. The main body 11 has an inner space 22, as shown in Fig. 5. Through the interior 22 Bohrspülung of the pump (not shown) to the drill head (not shown) transported against the flow direction B. At the drill head, the drilling suspension exits and takes up the drill cuttings loosened from the drill head and transports them through the annular space 102 in the flow direction B or from the borehole 100. In order to be able to increase the volume flow in the annular space 102 in a targeted manner, an opening 23 is provided in the base body 11 , which opens into a flow channel 24. The flow channel 24 has an inlet opening 25 which is aligned with the opening 23. Alternatively, there is the possibility that the inlet opening 25 and the opening 23 have different clear cross sections. In the opening 23, a nozzle 26 is provided, which defines the clear cross-section of the opening 23 or in this case the inlet opening 25.

The flow channel 24 extends within the wall 27 of the base body 1 1 and / or in the body 17 to an outlet opening 28. In the Outlet opening 28 is also a nozzle 29 is arranged, which defines the clear cross section of the outlet opening 28. Alternatively, diaphragms may be provided instead of the nozzles. The outlet opening 28 is arranged in a rearwardly disposed Be ^-th surface 30 of the body 17th The arrangement is provided axially to the borehole center. An incidence in the radial direction is also possible, for example, if the borehole wall is not solved by the emitted jet of Bohrsuspension.

The inlet opening 25 or the flow channel 24 in the region of the inlet opening 25 extends up to the top side 31 of the body 17 in order to provide access to the inlet opening 25 or opening 23 via which the nozzle 26 can be exchanged. In this access opening 32, a blind flange 33 is arranged. This can be disassembled to change the nozzle 26 can.

The outlet opening 28 with the nozzle 29 is in this case arranged on the rear side surface 30, so that the drill suspension emerging at the nozzle 29, the cuttings received from the receiving and transporting surface 19 and leaves this at the rear end 20 of the there leaking drilling suspension taken and thus the general flow of the drilling suspension in the annular space 102 again fed and transported in the direction of flow B from the well 100 addition. If a plurality of drill string elements 10 are arranged in a drill string, it is possible to equip each / several of the drill string members 10 with an individual nozzle assembly consisting of the nozzles 26 and 29 in order then to adapt the delivery of the drilling slurry in the borehole 100 to the individual installation locations.

By providing a plurality of drill string elements 10 in the drill string, the volume flow in the annular space is selectively increased. This is shown in Fig. 7 by the Zackendrave. This makes it possible to reduce the pressure losses in the annulus, which as a result leads to a total of less on the drill head Volumetric flow must be introduced into the annulus, whereby pressure losses can decrease and the pump performance can be reduced.

Starting from the drill head, the volume flow in the annular space 102 at each drill string element 10 is increased by the previously set volume flow. The serrated curve shown in Fig. 7 is merely for orientation to illustrate at which point a drill string member 10 has been incorporated into the drill string. The pressure losses can not be read off this curve.

In the example shown in FIG. 7, drill string elements 10 were used in the drill string 4 with a total drilling length of 1,500 meters. The clear cross-sections / nozzles 26, 29 of the individual drill string elements 10 were selected / set such that 200 liters per minute are delivered to the outlet openings 28 at each drill string element 10. At the drill head itself, a volume flow of 1,000 liters per minute is present. This results in a total flow of 1,800 liters per minute. It has surprisingly been found that according to the curve "summed pressure loss" in the annulus a pressure difference of 1, 8 bar results in a total drilling length of 1,500 m. The unexpected reduction of almost 2 bar in the annulus significantly reduces the risk of getting a blowout. At the same time, the wear is considerably reduced and the energy costs are significantly reduced by the reduced pump performance.

* _* ***

LIST OF REFERENCE NUMBERS

10 drill string element

1 1 basic body

12 front end

13 connecting element

14 back end

15 connecting element

16 outer wall

17 bodies

18 side surface

19 recording and

transport surface

20 back end

21 tip

22 interior

23 opening

24 flow channel

25 entrance opening

26 nozzle

27 wall

28 outlet opening

29 nozzle

30 side surface

31 top

32 access opening

33 blind flange

100 borehole

101 sole

102 annulus

103 borehole wall

A rotation direction

B flow direction in the annulus

Claims

claims

1. drill string element for installation in a drill string, in particular for horizontal or slant directional drilling (HDD or SDD), for creating a borehole (100) along a drill pipe, in particular for laying a pipeline, with a tubular base body (11) with two-sided connecting elements (13, 15) for connecting the drill string member (10) to the drill string, the drill string member (10) having an interior (22) through which a mud medium for flushing the wellbore (100) and removing it from the drill string with at least one opening (23) connected to the interior space (22) in a wall (16) of the base body (11), through which at least a portion of the flushing medium flowing through the interior is introduced into an annular space (102 ) passes between the borehole wall (103) and base body (11), characterized in that on the outer wall (16) above the Öf at least one body (17) is arranged, in which at least partially a flow channel (24) is arranged, that the flow channel (24) has at least one flow path and fluidly connected to the opening (23) via an inlet opening (25) is that the flow channel (24) on its side facing away from the opening (23) side at least one outlet opening (28), and that the clear cross section of the opening (23) and / or inlet opening (25) is smaller or larger than that clear cross section of the outlet opening (28).

2. Bohrstrangelement according to claim 1, characterized in that the outlet opening (28) is arranged substantially axially to the central axis of the Bohrstrangelements (10).

3. Bohrstrangelement according to claim 1 or 2, characterized in that the outlet opening (28) in a rear side surface arranged (30) of the body (17) is arranged.

4. Bohrstrangelement according to one of claims 1 to 4, characterized in that the clear cross section of the opening (23), the inlet opening (25) and / or the outlet opening (28) is adjustable.

5. Bohrstrangelement according to one of claims 1 to 4, characterized in that in the opening (23), the inlet opening (25), within the flow channel (24) and / or in the outlet opening (27) at least one nozzle (26, 29 ) and / or diaphragm is arranged, wherein preferably at least one nozzle (26, 29) and / or aperture is made changeable.

6. Bohrstrangelement according to one of claims 1 to 5, characterized in that the at least one body (17) extends on the base body (11), so that the outer radius of the base body (11) enlarged in sections and an eccentric is present through the the drill string during drilling temporarily from the borehole wall (103) can be raised.

7. Bohrstrangelement according to claim 6, characterized in that it is the at least one body (17) to exactly one body (17) or two bodies.

A drill string according to claim 6, characterized in that the at least one body (17) is two opposed bodies (17).

9. Bohrstrangelement according to one of claims 1 to 8, characterized in that on the body (17) has a side surface (18) is provided, designed as a receiving and transporting surface (19) for on a sole (101) of the borehole discontinued cuttings is.

A drill string according to claim 9, characterized in that the side surface (18) is helical with respect to the borehole axis.

11. Bohrstrangelement according to one of claims 1 to 10, characterized in that in the body (17) above the opening (23) and / or the Inlet opening an access opening (32) is arranged, in which a blind flange (33) is preferably provided as a closure element.

12. A drill string for creating a borehole along a drill pipe as HDD bore with at least two Bohrstrangelementen (10) according to one of claims 1 to 11, in which in which the clear cross sections of the openings (23) and / or inlet openings (25) and the Outlet openings (28) are set to each other, that at the installation point in the drill string, the flushing medium, each with predetermined volume flow and / or pressure in the annular space (102) is discharged.

13. Bohrstrangelement for installation in a Horizontal Directional Drilling (HDD) drill string for creating a borehole (100) along a drill pipe as HDD bore with a tubular base body (11) with two-sided connecting elements (13, 15) for connecting the Bohrstrangelements (10 ) with the drill string, the drill string member (10) having an interior space (22) through which a mud flushing medium (100) and removal of drill cuttings loosened by a drill bit connected to the drill string are transportable, characterized in that at least one body (17) which extends on the base body (11) is arranged on the outer wall (16) so that the outer radius of the base body (11) is enlarged in sections and an eccentric exists, through which the drill string during drilling temporarily from the borehole wall (103) can be raised.

14. Bohrstrangelement according to claim 13, characterized in that it is at least one body (17) to exactly one or two bodies, preferably opposite, is.

15. Bohrstrangelement according to claim 13 or 14, characterized in that at least one with the interior (22) connected to the opening (23) in a wall of the base body (11) is provided, through which at least a portion of the through the interior (22) flowing Rinsing medium in an annular space (102) between the borehole wall (103) and the base body (1 1) passes, that over the opening (23) of the body (17) is arranged in the at least partially a flow channel (24) is arranged, that the flow channel (24) has at least one flow path and fluidly connected to the opening (23) via an inlet opening (25), that the flow channel (24) on its from the opening (23 ) facing away from at least one outlet opening (28), and that the clear cross section of the opening (23) and / or inlet opening (25) is smaller or larger than the clear cross section of the outlet opening (28), preferably in conjunction with one of the claims 3 to 5, 7 to 1 1.

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