Well drill bit and method for drilling pipe installed underground

Abstract

The invention provides a drilling bit (1) comprising a pilot bit (2) and a reamer. The pilot bit (2) comprises a body (3) and a drilling surface (4). The drilling bit (1) is arranged to provide a bore for a pipe to be installed underground. The reamer comprises at least one wing (7) which is rotatably pivoted to the body (3) of the pilot bit (2) such that, when rotated to a drilling position, the wing (7) projects beyond the outer circle of the body (3) of the pilot bit (2) and, when rotated to a position rotated forward from the drilling position, the wing (7) projects beyond the outer circle of the body (3) of the pilot bit (2). The wings (7) do not extend out of the outer circle of the main body (3) of the pilot bit (2).

Description

Technical Field

[0001] The present invention relates to a well drilling drill bit, and in particular to a well drilling drill bit for drilling a pipe installed underground. Background Art

[0002] For a pipeline to be installed underground, the size of the drilled hole must be at least equal to the outer diameter of the pipeline. WO2015059341A1 discloses a drilling device, which includes: a pilot drill bit for drilling the central part of the hole; an annular drill bit detachably connected to the pilot drill bit, used as an expander to drill the outer circle of the hole; and a device for pulling a casing into the hole during the drilling process.

[0003] A problem with drilling equipment of the type mentioned in the above examples is that when the drilling equipment is pulled out of the borehole so that the casing remains in the borehole, the annular drill bit that drilled the outer circle of the hole needs to be left at the bottom of the borehole, located at the end of the casing.

[0004] Therefore, several different devices using movable wings as reamer have been proposed. For example, devices of this type are proposed in the publications GB 2465653A, US 5934394A, US 5975222A and WO 2005085581A1. There is still a need to provide a new drilling bit and a method for drilling a hole for a pipe installed underground. Summary of the invention

[0005] Therefore, the object of the present invention is to develop a new well drilling drill bit and a method for drilling a hole for a pipe installed underground. The features of the device according to the invention are disclosed in the independent claim. Some embodiments of the invention are disclosed in the dependent claims.

[0006] The present invention provides a drilling bit, which includes a pilot drill bit and a reamer. The pilot drill bit includes a body and a drilling surface. The drill bit is arranged to provide a hole for a pipe to be installed underground. The reamer includes at least one wing portion, which is rotatably pivoted to the body of the pilot drill bit so that when the wing portion is rotated to a drilling position, the wing portion extends beyond the outer circle of the pilot drill bit body, and when the wing portion is rotated to a position rotated forward from the drilling position, the wing portion does not extend beyond the outer circle of the pilot drill bit body. The drilling surface of the pilot drill bit can also be referred to as a frontal area, and the wing portion has a corresponding frontal area. The arrangement can also be described as allowing the wing portion to rotate forward and then rotate backward, whereby the angle between the frontal area of ​​the pilot drill bit and the frontal area of ​​the wing portion will change. In such an arrangement, a hole can be effectively formed for a pipe to be installed underground. In addition, the wing portion can be reliably located in such a position that the drill bit can be completely removed from the inside of the pipe to be installed underground. Similarly, the area of ​​the outermost part of the wing can be very large, so that the drilling surface of the wing located on the outermost part of the drilling bit is relatively large. The wing comprises at least one bracket and an outer part, so that the outer part of the wing is arranged to divert the flow of the flushing medium. Then, the arrangement also controls the flow of the flushing medium as required. According to one embodiment, at least two wings as described above are provided. The distance between the wings can be set to be quite small, which provides good drilling performance. The shape of the wing can be simple and easy to manufacture.

[0007] The wing comprises at least one bracket and an outer part. Such a wing has a simple shape. The wing can be pivoted from the bracket. The outer part can be formed to a desired size and shape. The outer part can be wider than the bracket, for example.

[0008] According to one embodiment, the wing comprises an outer portion, at least the outer surface of which is curved. The shape of the outer portion then enables the drill bit to work reliably.

[0009] According to one embodiment, the drilling surface of the pilot drill bit comprises a flushing slot. The wing may comprise an outer portion, such that the flushing slot is arranged to deliver a flushing medium to the outer portion of the wing, and the outer portion of the wing is arranged to divert the flow of the flushed medium towards the rear portion of the drilling bit. The flow of the flushing medium may then be controlled in a desired manner.

[0010] According to one embodiment, the wing comprises, from the outside of the wellbore bit towards the central part, at least two brackets, between which the flushing slots are arranged. Thus, the flow of the flushing medium can be controlled particularly precisely and reliably.

[0011] According to one embodiment, the drilling bit comprises a pivot pin (in the pilot bit body) connected to each wing, the wing being arranged to be rotatable about the central axis of the pivot pin. This arrangement makes the mechanism simple, so that the wing can rotate reliably.

[0012] According to one embodiment, the central axis of the pivot pin is in a substantially perpendicular direction relative to the central axis of the drill bit. This arrangement also increases the reliability of the structure. In this regard, "substantially perpendicular direction" means that the angle between the central axis of the pivot pin and the central axis of the drill bit is between 70-110°, preferably between 80-100°.

[0013] According to one embodiment, the wing comprises at least two brackets, at the ends of which a pivot pin is arranged. This shape of the wing is preferred, and the pivoting of the wing can also be achieved reliably.

[0014] According to one embodiment, the at least two brackets comprise their own independent pivot pins at their ends. Then, the two brackets are not pivoted by only one pivot pin, so that there is no need to drill a long hole for the pivot pin through the pilot drill. Therefore, the body of the pilot drill can be formed to be strong and durable.

[0015] According to one embodiment, the wing comprises a drilling surface, wherein both the drilling surface of the pilot drill bit and the drilling surface of the wing are provided with drilling bumps.

[0016] According to one embodiment, the body of the pilot drill bit comprises a shoulder of a shoe for a pipe to be installed underground, wherein the pipe to be installed underground can be pulled into the ground by means of the shoulder. This arrangement is simple and reliable for the installation of the pipe to be installed underground.

[0017] According to one embodiment, when the wing is rotated to the drilling position, it is substantially perpendicular to the direction of the central axis of the drill bit. This structure is simple and reliable. In this regard, "substantially perpendicular" means that when the wing is rotated to the drilling position, the angle between the direction of its front area and the central axis of the drill bit is between 70-110°, preferably between 80-100°.

[0018] According to one embodiment, when the wings are rotated from the drilling position to the forward rotation position, the wings are rotated forward at least 30° from a direction perpendicular to the central axis of the drilling bit. This arrangement ensures that the drilling bit can be easily and simply removed from the inside of the pipe to be installed underground.

[0019] According to one embodiment, the blank of the wing is formed by flame cutting a sheet. Thus, the manufacture of the wing becomes easy and simple. Material loss is minimal. For example, the wing can be made of wear-resistant steel. In addition, the wing can be formed of engineering steel or a forged blank, for example in the round bar type.

[0020] According to one embodiment, a method for drilling a pipe installed underground uses the drill bit proposed herein. When drilling, the wings are rotated to the drilling position to extend beyond the outer circumference of the guide drill bit body. When the drilling bit is removed from the inside of the pipe, the wings are rotated to the forward rotation position so that the wings do not extend beyond the outer circumference of the guide drill bit body. This solution is simple and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The invention will now be described in more detail with reference to some embodiments and with reference to the accompanying drawings, in which:

[0022] Figure 1 is a schematic oblique front view of a well drilling bit, wherein the well drilling bit is in a drilling position;

[0023] Figure 2 yes Figure 1 A schematic oblique front view of a well drilling bit of FIG. 1 , wherein the well drilling bit is in a position to be removed from the interior of the pipe;

[0024] Figure 3 yes Figure 1 A schematic front view of a drilling bit;

[0025] Figure 4 yes Figure 1 A schematic oblique front view of a well drilling drill bit of FIG. 1 , wherein the pilot drill bit body is shown in perspective;

[0026] Figure 5 yes Figure 1 A schematic cross-sectional side view of a well drilling bit of FIG. 1 , wherein the well drilling bit is in a drilling position; and

[0027] Figure 6 yes Figure 1 Schematic cross-sectional side view of a well drilling bit in which the well drilling bit is in a position to be removed from the interior of a pipe. DETAILED DESCRIPTION

[0028] Figure 1 A wellbore drill bit 1 comprising a pilot drill bit 2 is shown. The pilot drill bit 2 comprises a body 3 and a drilling surface 4. The wellbore drill bit 1 further comprises wings 7. The wings 7 provide the reamer of the wellbore drill bit 1 and they are rotatably pivoted to the body 3 of the pilot drill bit 2.

[0029] When the wing 7 is Figure 1 When the drill bit 2 is rotated to the drilling position in the manner shown, the wing 7 extends beyond the outer circumference of the main body 3 of the pilot drill bit 2. Figure 3. Each wing 7 includes a wing drilling surface 11. The drilling surface 4 of the pilot drill bit and the drilling surface 11 of the wing may include a drilling bump 12. When drilling, the drilling bit 1 moves back and forth and rotates, that is, the drilling bit 1 is used for impact and rotation drilling. The drilling bit 1 can be used to drill holes underground and can also be used to drill holes in hard materials such as rocks.

[0030] The pilot drill body 3 may include a shoulder 5. The shoulder 5 may be arranged against a shoe 6. The shoe 6 may be fastened at the bottom end of the pipe to be installed underground. The pipe to be installed underground may then be installed underground with the aid of the shoulder 5 and the shoe 6. For clarity, Figure 1-4 The pipe to be installed underground (to which the overshoe 6 is fastened) is not shown. Figure 5 and 6 A pipe 16 to be installed underground is shown. The pipe to be installed underground may be permanently installed or set underground. Instead of using shoulders and overshoes, the pipe 16 may be arranged underground, for example so that the pipe is pressed, driven and / or vibrated into the ground from its top end. The diameter of the pipe 16 to be installed underground may be, for example, 100-1,000 mm.

[0031] The pilot drill bit 2 and the wings 7 provide a hole for the pipe to be installed underground. In the drilling position, the wings 7 extend beyond the outer circumference of the body 3 of the pilot drill bit 2 so that the size of the hole provided is at least equal to the size of the pipe to be installed underground.

[0032] The drilling bit 1 is pushed in the drilling direction to expand the drilling surface, that is, the wing 7 rotates to the drilling position. When the drilling bit 1 is pulled out of the hole, the wing 7 rotates to Figure 2 The position shown. When rotating forward from the drilling position to this position, the wing does not extend beyond the outer circle of the pilot drill bit body. When rotating forward, the wing 7 rotates toward the bottom of the borehole in the drilling direction. Then, the drilling bit 1 can be pulled out from the inside of the pipe installed underground. Then, the wing 7 does not extend beyond the outer circle of the body 3 of the pilot drill bit 2. In the illustrated embodiment, in this position, the wing 7 does not extend beyond the circle defined by the inner diameter of the overshoe 6. The circle outside of which the wing 7 does not extend can be smaller than the outer diameter of the body 3 of the pilot drill bit 2 in the width of the shoulder 5.

[0033] The wing 7 comprises at least one bracket 8 and an outer part 9. The outer part 9 may be, for example, wider than the bracket 8. The width of the outer part 9 may be made as large as possible, so that the well drilling drill bit 1 also comprises as many drilling surfaces as possible on the outer circumference. When the well drilling drill bit 1 also comprises a large number of drilling surfaces on its outer circumference, as many drilling protrusions 12 as possible may also be provided on the outer circumference. The width of the outer part 9 may, for example, be such that the combined width of the outer part 9 is greater than the combined width of the gaps between the outermost parts of the wing 7. At least the outer surface of the outer part 9 may be curved.

[0034] The brackets 8 extend from the outer portion 9 towards the central portion of the pilot drill bit 2. For example, in the embodiment shown in the figures, the wing 7 comprises two brackets 8, both of which extend towards the central portion of the pilot drill bit 2, although neither of them extends towards the central point of the pilot drill bit, but slightly misses the central point.

[0035] The wing 7 can be pivoted from the bracket 8. In the body 3 of the pilot drill bit 2, the drilling drill bit 1 may include a pivot pin 10 connected to each wing 7, the wing 7 being rotatable about the central axis of the pivot pin 10. The pivot pin 10 may be arranged through one end of the bracket 8. The pivot pin 10 may be locked to the body 3 of the pilot drill bit 2, for example, by a locking ring made of polyurethane. In addition, the pivot pin may be locked in some other way, for example by a locking pin or any mechanical stop that prevents the pivot pin from sliding out.

[0036] The wing 7 may comprise two or more brackets 8, and the wing 7 may then be pivoted by a pivot pin 10 which is Figure 4 The illustrated manner extends through all brackets 8. On the other hand, the at least two brackets 8 may comprise their own independent pivot pins 10 at their ends. Then, the two brackets 8 are therefore not only pivoted by one pivot pin 10, thereby eliminating the need to drill an elongated hole for the pivot pin 10 through the body 3 of the pilot drill bit 2.

[0037] The center axis of the pivot pin 10 may be in a direction substantially perpendicular to the center axis direction of the well drilling bit 1. Then, the center axis of the pivot pin may be in a direction perpendicular to the center axis direction of the well drilling bit 1, or differ from the vertical direction by, for example, up to 20°, preferably up to 10° in each direction.

[0038] The drilling surface 4 of the pilot drill bit 2 may comprise a flushing groove 13. A flushing medium, such as compressed air, may be supplied along a flushing channel 14, for example in the center of the drilling bit 1, towards the front surface of the drilling bit 1. The drilling bit 1 may comprise a drilling surface 4 of the pilot drill bit 2, which is located at the end of the flushing channel 14, wherein there is a certain body structure at the end of the flushing channel 14. Thus, the flushing medium at least does not flow completely in the drilling direction, i.e. the axial direction of the drilling bit 1 towards the ground to be drilled, but the flushing medium flow is at least partially diverted to the radial direction of the drilling bit 1.

[0039] After the flushing channel 14, at least part of the flushing medium flow flows from the central part of the drilling bit 1 to the outer edge of the drilling bit in the flushing groove 13. The flushing groove 13 delivers the flushing medium to the outer part 9 of the wing 7. The outer part 9 of the wing 7 is arranged to divert the flushing medium flow to the side groove 15 and flow to the rear part of the drilling bit 1. The flushing medium can then flow upwards in the pipeline to be installed underground and avoid the flushing medium flowing into the underground.

[0040] In the embodiment shown in the figures, the wing 7 comprises at least two brackets extending from the outer part 9 towards the central part of the wellbore drill bit 1. Between these brackets 8, a flushing slot 13 is arranged.

[0041] The outer part 9 of the wing directs the flushing medium flow in the desired direction. For the flow of the flushing medium, the borehole surface does not necessarily need flushing grooves. The flushing medium flows between the borehole surface and the wing. The surface of the wing located on the borehole surface side may include flushing grooves for the flushing medium. On the other hand, the flushing medium may be arranged on both the borehole surface and the wing surface, or only one of them includes flushing grooves, or neither of them includes flushing grooves.

[0042] If the wing comprises two brackets 8, the wing can be constructed so that the brackets 8 are connected to each other by the wing material over a length exceeding half the length of the bracket. Such a wing structure is stronger than a structure in which the brackets are not joined until near the outer part 9 of the wing. When the brackets are connected to each other by the wing material over a length exceeding half the length of the bracket, the wing reliably guides the flow of the flushing medium. Then, a flushing groove for the flushing medium can also be provided at the location where the wing joins the bracket.

[0043] When rotated to the drilling position, the wing 7 may be substantially perpendicular to the central axis direction of the drilling bit 1. Then, when rotated to the drilling position, the wing 7 may be perpendicular to the central axis direction of the drilling bit 1, or differ from the vertical direction by, for example, up to 20°, preferably up to 10° in each direction.

[0044] When rotating from the drilling position to the forward rotation position, the wing 7 can be rotated forward by at least 30° from a direction perpendicular to the central axis direction of the drilling drill bit 1. According to one embodiment, when rotating from the drilling position to the forward rotation position, the wing 7 is rotated forward by at least 45° from a direction perpendicular to the central axis direction of the drilling drill bit 1. The amount by which the wing needs to be rotated when rotating to the forward rotation direction depends on the size class and geometry of the drill bit and the amount of space available. In larger size classes, a sufficient change in the outer diameter of the drill bit can be provided by a smaller angle change than in smaller size classes. In the embodiment of the accompanying drawings, the wing is rotated by 66°.

[0045] Preferably, the wings 7 are rotatable by less than 90°. Then, when the drilling bit 1 is pressed against the ground, the wings 7 can be rotated into the drilling position without a separate actuator to move them. Thus, the wings can be moved forwards and backwards by the actuator. The structure associated with the drilling bit 1 is subjected to very severe loads. Therefore, it is preferred to provide such a drilling bit 1 - without using an actuator to move the wings 7. Then, when the drilling bit 1 is moved forwards, this causes the wings 7 to rotate into the drilling position, and when the drilling bit 1 is moved backwards, this causes the wings 7 to rotate into a position rotated forwards from the drilling position.

[0046] The blank of the wing 7 can be formed by flame cutting a plate. The wing can be made of, for example, wear-resistant steel. In addition, the wing can be formed of, for example, round bar-shaped engineering steel or a forged blank.

[0047] The method for drilling a pipe to be installed underground can use the drilling bit 1 proposed here. When drilling, the wing 7 is rotated to the drilling position to extend beyond the outer circumference of the main body 3 of the pilot drill bit 2. When the drilling bit 1 is removed from the inside of the pipe, the wing 7 is in a position rotated forward from the drilling position so that the wing 7 does not extend beyond the outer circumference of the main body 3 of the pilot drill bit 2. Preferably, this rotation of the wing 7 to and from the drilling position can be performed without an actuator and can be achieved by moving the drilling bit 1 forward and backward. The flow of the flushing medium is diverted by means of the outer part 9 of the wing.

[0048] A person skilled in the art will find that it is obvious that, as technology advances, the basic idea of ​​the invention can be implemented in many different ways. Therefore, the invention and its embodiments are not limited to the examples described above, but may vary within the scope of the claims.

Claims

1. A drilling bit, comprising: A pilot drill bit (2) comprising a body (3) and a drilling surface (4); and a reamer, wherein the drilling bit (1) is arranged to provide a hole for a pipe to be installed underground, characterized in that The reamer comprises at least one wing (7) which is rotatably pivoted to the body (3) of the pilot drill bit (2) so that when the wing (7) is rotated to a drilling position, the wing (7) extends beyond the outer circle of the body (3) of the pilot drill bit (2), and when the wing (7) is rotated to a position forward from the drilling position, the wing (7) does not extend beyond the outer circle of the body (3) of the pilot drill bit (2). The wing (7) comprises at least one bracket (8) and an outer part (9), and the outer part (9) of the wing (7) is arranged to divert the flow of flushing medium.

2. The well drilling drill bit according to claim 1, characterized in that: The reamer comprises at least two wings (7), and the wings (7) are rotatably pivoted to the main body (3) of the guide drill bit (2), so that when the wing is rotated to the drilling position, the wing (7) extends beyond the outer circle of the main body (3) of the guide drill bit (2), and when the wing is rotated to a position forward from the drilling position, the wing (7) does not extend beyond the outer circle of the main body (3) of the guide drill bit (2).

3. The well drilling drill bit according to claim 1 or 2, characterized in that: The wing (7) comprises an outer portion (9), at least the outer surface of which is curved.

4. A well drilling drill bit according to any one of the preceding claims, characterised in that The pilot drill bit (2) has a flushing groove (13) on its drilling surface (4), and the wing (7) comprises an outer portion (9), so that the flushing groove (13) is arranged to convey a flushing medium towards the outer portion (9) of the wing (7), and the outer portion (9) of the wing is arranged to divert the flow of the flushing medium towards the rear portion of the drilling drill bit (1).

5. The well drilling drill bit according to claim 4, characterized in that: The wing (7) comprises at least two brackets (8) from the outer part (9) towards the central part of the drilling bit (1), and the flushing slot (13) is arranged between the at least two brackets (8).

6. A well drilling drill bit according to any one of the preceding claims, characterised in that The well drilling bit (1) comprises a pivot pin (10) connected to each wing (7), the wing (7) being arranged to rotate about a central axis of the pivot pin.

7. The well drilling drill bit according to claim 6, characterized in that: The central axis of the pivot pin (10) is in a direction substantially perpendicular to the direction of the central axis of the drilling bit (1).

8. The well drilling drill bit according to claim 6 or 7, characterized in that: The wing (7) comprises at least two brackets (8), the pivot pin (10) being arranged at the ends of the at least two brackets.

9. The well drilling drill bit according to claim 8, characterized in that The brackets (8) are connected to each other through the material of the wing parts, and the connection length is greater than half the length of the brackets.

10. The well drilling drill bit according to claim 8 or 9, characterized in that: The at least two brackets (8) comprise respective separate pivot pins (10) at their ends.

11. A well drilling drill bit according to any one of the preceding claims, characterised in that The wing (7) comprises a drilling surface (11), wherein the drilling surface (4) of the pilot drill bit (2) and the drilling surface (11) of the wing (7) comprise drilling bumps (12).

12. A well drilling drill bit according to any one of the preceding claims, characterised in that The body (4) of the pilot drill bit (2) comprises a shoulder (5) of a shoe (6) for a pipe to be installed underground, wherein the pipe to be installed underground can be pulled into the ground by means of the shoulder (5).

13. A well drilling drill bit according to any one of the preceding claims, characterised in that When rotated to the drilling position, the wing portion (7) is substantially perpendicular to the direction of the central axis of the drilling bit (1).

14. A well drilling drill bit according to any one of the preceding claims, characterised in that When rotating from the drilling position to the forward rotating position, the wing (7) rotates forward by at least 30° from a direction perpendicular to the direction of the central axis of the drilling bit (1).

15. A method for drilling a hole for a pipe to be installed underground, the method comprising using a drilling bit (1) according to any one of claims 1 to 14 when drilling, rotating the wing (7) to a drilling position to extend beyond the outer circumference of a main body (3) of a guide drill bit (2), and when the drilling bit (1) is removed from the inside of the pipe, the wing (7) is in a position rotated forward from the drilling position so that the wing (7) does not extend beyond the outer circumference of the main body (3) of the guide drill bit (2).

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