Pulse high-power drilling bits and drilling tools

Abstract

The drilling bit (230) for the drilling tool (1) comprises a bit body (231) defining a through channel (231C) for the passage of a fluid flow and having an outer surface (232). Extending from the outer surface (232) are a plurality of drilling members (233) evenly distributed on the outer surface (232). Each drilling member (233) has a fin (233A) extending from the outer surface (232) and a plurality of drilling teeth (233B) extending from the fin (233A). Each drilling tooth (233B) has a base (233B1) and a cutting element (233B2) disposed at an end of the base (233B1). The drilling bit (230) has a high voltage electrode (232C) centrally disposed in the central face opening (231A1). Each drilling member (233) has a ground electrode (233C) located at the end of a fin (233A) at the high voltage electrode (232C) so as to extend at least partially along the central opening (231A1).

Description

Technical Field

[0001] The present invention relates to the field of excavation, and particularly to a pulsed high-power rotary excavation tool.

Background Art

[0002] In the field of excavation, it is known to use rotary excavation tools for excavating rock. In known solutions, this type of tool comprises a bit provided with teeth for excavating soil or rock by rotation. Such purely mechanical rotary excavation can be particularly time-consuming, especially in the case of particularly hard rock.

[0003] As another known solution, there is a method of using a pulsed high-power tool that induces an electric arc in the rock from a high-voltage electrode and a ground electrode that receive a high potential difference on the order of, for example, several tens of kilovolts to several hundreds of kilovolts. However, in this solution, since only the rock is broken by a pair of electrodes, the process may be relatively time-consuming.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Patent Document 1 relates to a drilling tool in which the bit consists of an electropolishing electrode. In one embodiment shown in Figure 5 of this document, the bit consists of both teeth and a high-voltage electrode surrounded by an annular ground electrode. Therefore, the electrical pulse is concentrated only at the center of the tool head, which may limit its effectiveness and is therefore a disadvantage. Furthermore, the electrode may be damaged as it is directly exposed to rock during the rotation of the bit. In one embodiment shown in Figure 6 of this document, the bit consists of multiple rows of teeth, a high-voltage electrode, and a remote electrode positioned in place of a predetermined row of teeth. However, this configuration also has disadvantages, as the efficiency may be limited as the electrical pulse is concentrated only on one side of the tool. Furthermore, the electrode may be damaged as it is directly exposed to rock during the rotation of the bit. In embodiments of this prior art shown in Figures 35 to 37, the tool has no teeth and does not rotate to avoid damaging the electrodes. The high-voltage electrode is positioned in the center of the front surface of the bit. The ground electrode is positioned around the high-voltage electrode at the periphery of the front surface of the bit. This configuration has disadvantages in that a lot of energy is required to generate pulses between each high-voltage electrode and the ground electrode. Furthermore, since these tools are electrically powered and not mechanically rotary, drilling can be time-consuming. Additionally, it is uncertain whether electrical pulses are effectively generated, as this depends on the dielectric properties of the medium between the high-voltage electrode and the ground electrode.

[0006] Therefore, a simple and effective solution is needed that overcomes at least some of these shortcomings. [Means for solving the problem]

[0007] For this purpose, the present invention first relates to a drilling tool bit. The bit comprises a bit body. The bit body has a drilling surface and a surface for attaching the bit to the rotor assembly of a drilling tool. The bit body defines a through channel for passing a fluid flow connecting the attachment surface and the drilling surface by opening at a circular central surface opening in the drilling surface. The drilling surface has an outer surface connecting the central surface opening and the attachment surface. A plurality of drilling members, evenly distributed on the outer surface, extend from the drilling surface. Each drilling member has a fin and a plurality of drilling teeth extending from the fin. The fin extends radially from the outer surface into the central surface opening from the attachment surface. The plurality of drilling teeth are arranged side by side between a first drilling tooth located at the end of the drilling surface and a last drilling tooth located on the side of the attachment surface. Each drilling tooth includes a base and a cutting element located at the end of the base. The bit has a high-voltage electrode located in the through channel at the center of the central surface opening recessed from the first drilling tooth of each drilling member. Each drilling member has a grounding electrode. The grounding electrode is positioned at the end of a fin in the high-voltage electrode so as to extend at least partially along a recessed central opening from the first drilling tooth of the drilling member.

[0008] Each of the multiple pairs of electrodes formed by the high-voltage electrode and the ground electrode is configured to generate an electric arc when the pair of electrodes receives a voltage supplied across it by a high-power pulse generator. Thus, the through-channel passes through the bit body and opens at the central opening, allowing the fluid flow to be transported through the bit so as to continuously circulate around the high-voltage electrode. Therefore, the through-channel forms a fluid screen with dielectric function that enables the formation of an arc between the high-voltage electrode and one of the multiple ground electrodes. When the rotor assembly is driven to rotate by the turbine, the bit rotates on its own and mechanically drills into the rock using its teeth. At this time, the tangential velocity of the ground electrode is greater than that of the high-voltage electrode. Since the high-voltage electrode is located in the center of the front surface of the bit body, its tangential velocity is close to zero. Therefore, when a voltage is applied between the high-voltage electrode and the multiple ground electrodes, an electric arc is generated between the high-voltage electrode and one of the multiple ground electrodes through the rock while the bit rotates. This arrangement and operation allows the rotating bit to be brought as close as possible to the area weakened by electric fracturing, while protecting the high-voltage electrode and ground electrode from direct friction with the rock. The fluid circulating between the high-voltage electrode and ground electrode has two functions: it acts as a dielectric element, facilitating the electric arc's passage through the rock and fracturing it, and it also functions as drilling slurry, transporting rock fragments to the surface and discharging them through fluid circulation. Furthermore, the fluid flow enables cleaning of the area between the electrodes.

[0009] According to one aspect of the present invention, the drilling members are evenly distributed on the outer surface surrounding the bit body, thereby allowing drilling slurry to flow between the drilling members and improving drilling efficiency, particularly mechanical drilling.

[0010] Preferably, the bit body has at least three, preferably four, five, or six drilling members, thereby improving drilling efficiency while allowing drilling mud to flow between the drilling members.

[0011] According to the features of the present invention, by integrally forming the fins with the outer surface of the bit body, the rigidity of the bit can be improved, and consequently, the drilling efficiency can be improved.

[0012] According to another feature of the present invention, in order to improve the rigidity of the bit and, consequently, improve drilling efficiency, the base of the teeth of the drilling member is integrally formed with the fins of the drilling member.

[0013] Preferably, the fins curve in the opposite direction to the rotation of the bit and extend outward for the purpose of drilling efficiency.

[0014] Preferably, in order to improve drilling efficiency, each drilling member has at least three, preferably four, five, or six drilling teeth.

[0015] According to the features of the present invention, in order to strengthen the teeth and thereby improve the drilling efficiency and lifespan of the tool, the base is substantially cylindrical in shape and extends in a direction perpendicular to the rotation axis of the bit.

[0016] Advantageously, the cutting element consists of a hard, abrasive drilling material, such as interconnected polycrystalline diamond particles, particularly "polycrystalline diamond compact" (PDC) type polycrystalline diamond particles.

[0017] Preferably, since multiple grounding electrodes are identical, the high-voltage electrode and the grounding electrode each have at least a partially spherical shape to slow down electrode erosion. Alternatively, the electrodes may have a pointed shape, such as a cone, or other suitable shape.

[0018] In one embodiment, each of the multiple electrodes has at least a partially spherical shape. The diameter of the high-voltage electrode is equal to at least twice the diameter of each ground electrode so that an electric arc can be formed between the high-voltage electrode and any of the multiple ground electrodes.

[0019] According to one aspect of the present invention, the high-voltage electrode and the six ground electrodes are made of a conductive material, for example, preferably made of a metal such as steel.

[0020] The present invention also relates to a high-pulse rotary drilling tool. The drilling tool includes a stator assembly and a rotor assembly. The stator assembly includes a hollow cylindrical body having a mounting end adapted to be connected to a drilling rod and a free end. The rotor assembly includes a turbine, a high-power pulse generator, and the bit described above. The turbine is mounted in the body at the mounting end and is configured to be driven by a fluid flow supplied by the drilling rod to rotationally drive the rotor assembly. The high-power pulse generator is mounted inside the body and is integrally connected to the turbine. The bit extends from the cylindrical body at the free end of the stator assembly.

[0021] In one embodiment, the drilling tool further includes a generator configured to convert the mechanical energy of the rotating turbine into electrical energy for supplying the high-power pulse generator.

[0022] Preferably, the generator is mounted inside the stator assembly.

[0023] Advantageously, the drilling tool further includes a drilling motor mounted inside the body, integrally connected to the high-power pulse generator, and configured to be driven by the fluid flow that has passed through the turbine.

[0024] Advantageously, the drilling tool further includes a steering device integrally connected to the bit. The steering device receives the power provided by the turbine or the increased power provided by the drilling motor, transmits the power to the bit, directs the bit in a predetermined direction, and is in the form of a hinged tube configured to transmit the fluid flow from the turbine to the bit.

[0025] Further features and advantages of the present invention will become more apparent upon reading the following description, which is purely illustrative and should be read in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0026] [Figure 1] It is a side sectional view of a cutting part showing an embodiment of a drilling tool according to the present invention. [Figure 2] It is a perspective side sectional view of a device and a bit for steering the tool of FIG. 1. [Figure 3] It is a front view of the bit of the tool of FIG. 1. [Figure 4] It is a perspective side sectional view of the bit of FIG. 1, particularly showing a part of the teeth.

Mode for Carrying Out the Invention

[0027] An example of a drilling tool 1 according to the present invention is shown in the figure. The drilling tool 1 is rotary and has a pulsed high output.

[0028] I) Drilling tool 1 Referring to FIG. 1, the drilling tool 1 includes a stator assembly 10 and a rotor assembly 20.

[0029] 1) Stator assembly 10 The stator assembly 10 includes a hollow cylindrical body 110 composed of a mounting end portion 110A adapted to be connected to the drilling rod 2 and a free end portion 110B.

[0030] 2) Rotor assembly 20 The rotor assembly 20 includes a turbine 210, a high-output pulse generator 220, and a bit 230. In this preferred but non-limiting embodiment, the drilling tool 1 further includes a generator 240, a drilling motor 250, and a steering device 260.

[0031] a) Turbine 210 The turbine 210 is mounted within the main body 110 of the stator assembly 10 at its mounting end 110A and is configured to be driven by a fluid flow supplied from the drilling rod 2 in order to rotate the rotor assembly 20.

[0032] b) Generator 240 The generator 240 is configured to convert the mechanical energy of the rotating turbine 210 into electrical energy.

[0033] c) High-power pulse generator 220 The high-power pulse generator 220 is mounted inside the main body 110 of the stator assembly 10 and is integrally connected to the turbine 210.

[0034] d) Excavation motor 250 The drilling motor 250 is a "mud motor (drilling motor)" type. The drilling motor 250 is mounted inside the main body 110 of the stator assembly 10 by being integrally connected to the high-power pulse generator 220. The drilling motor 250 is configured to be driven by the fluid flow that has passed through the turbine 210 in order to increase the torque generated from the turbine 210 and supply the increased torque to the bit 230 via the steering device 260.

[0035] e) Steering device 260 The steering device 260 is connected to the drilling motor 250 on one end and integrally connected to the bit 230 on the other end.

[0036] The steering device 260 is in the form of a hinged tube configured to receive the increased power supplied by the drilling motor 250, transmit the increased power to the bit 230, orient the bit 230 in a predetermined direction, and transmit fluid flow from the turbine 210 to the bit 230 via the drilling motor 250.

[0037] f) Bit 230 Referring to Figure 2, the bit 230 is connected to the steering device 260 via a tubular connector 270, extending from the hollow cylindrical body 110 of the stator assembly 10 via a free end 110B. The bit 230 rotates around the rotation axis X.

[0038] The bit 230 comprises a bit body 231 having a drilling surface 231A and a mounting surface 231B (Figure 2). The drilling surface 231A is designed to contact rock in order to grind the rock. The mounting surface 231B is configured to attach the bit 230 to the tubular connector 270 so that the bit body 231 and the tubular connector 270 are coaxially connected.

[0039] The bit body 231 opens at a circular central opening 231A1 (Figure 3) of the drilling surface 231A, particularly for discharging rock debris, and defines a through channel 231C for circulating fluid flow from the bit 230 to the rock, connecting the mounting surface 231B at the connection point with the tubular connector 270 to the drilling surface 231A.

[0040] Referring to Figures 3 and 4, bit 230 is positioned in the center of the central opening 231A1 and includes a hemispherical high-voltage electrode 232C whose axis is the same as the axis of rotation X. The axis of rotation X passes through the center of the central opening 231A1 and the center of the high-voltage electrode 232C.

[0041] The bit body 231 has an outer surface 232 extending from a central opening 231A1 to a mounting surface 231B. Multiple drilling (or cutting) members 233 adapted for breaking rock extend from the outer surface 232.

[0042] The drilling members 233 are preferably integrally formed with the bit body 231 and are evenly distributed on the outer surface 232 surrounding the bit body 231. In the illustrated example, the bit 230 comprises six drilling members 233, although this is not limiting.

[0043] Each drilling member 233 has a fin 233A. The fin 233A is curved and extends in the radial direction opposite to the rotation of the drilling bit 230 for the purpose of drilling efficiency, and is integrally formed with the outer surface 232.

[0044] Each fin 233A has a distal end that partially extends into the central surface opening 231A1 and a proximal end located at the junction between the outer surface 232 and the mounting surface 231B (see Figure 2). Each of two adjacent pairs of fins 233A defines a groove 234 that allows for the discharge of drilling mud in particular.

[0045] The drilling teeth 233B are arranged in a line along the fin 233A from the distal end to the proximal end, and are integrally formed with the fin 233A. In the illustrated example, particularly in Figure 4, each drilling member 233 has five drilling teeth 233B.

[0046] As shown in Figures 2 to 4, each drilling tooth 233B extends from the fin 233A in a direction perpendicular to the rotation axis X of the bit 230 in order to efficiently drill through the rock. As shown in Figure 2, the assembly of each first drilling tooth of each drilling member 233 forms the end where the bit body 231 first makes contact with the rock.

[0047] The high-voltage electrodes 232C are recessed from the first drilling teeth 233B of each drilling member 233, i.e., recessed into the through-channels 231C for fluid passage, to protect them from friction from rocks during the rotation of the bit 230.

[0048] Referring to Figures 3 and 4, each drilling tooth 233B has a base 233B1 and a cutting element 233B2. The base 233B1 is integrally formed with the fin 233A and has a substantially cylindrical shape extending in a direction perpendicular to the rotation axis X of the bit 230. The cutting element 233B2 is positioned at the end of the base 233B1 in the rotation direction of the bit 230 in order to drill rock by the rotation of the rotor assembly 20. The cutting element 233B2 is formed from interconnected polycrystalline diamond particles, including a hard, abrasive drilling material, such as the "polycrystalline diamond compact" (PDC) type. The cutting element 233B2 may be manufactured separately from the bit body 231 and then attached to the base 233B1 using a bonding material such as a solder alloy.

[0049] Each drilling member 233 is provided with a grounding electrode 233C. The grounding electrode 233C is located at the end of the fin 233A in the high-voltage electrode 232C and extends at least partially along the central surface opening 231A1. Similar to the high-voltage electrode 232C, each grounding electrode 233C is recessed from the first drilling teeth 233B of the drilling member 233, i.e., recessed into a through channel 231C for fluid passage, to protect it from friction from rocks during the rotation of the bit 230. Advantageously, each grounding electrode 233C has a hemispherical shape, and its axis may be slightly inclined with respect to the high-voltage electrode 232C, for example between 0 and 30°, to improve the formation of an electric arc between the high-voltage electrode 232C and the grounding electrode 233C.

[0050] The high-voltage electrode 232C and the ground electrode 233C are made of a conductive material, preferably a metal such as steel.

[0051] Each pair of electrodes, formed by the high-voltage electrode 232C and the ground electrode 233C, is configured to generate an electric arc when it receives a voltage supplied across the pair of electrodes by the high-power pulse generator 220.

[0052] II) Examples The fixed cutting drill bit 230 may be positioned in the hole such that the cutting element 233B2 abuts against the rock layer being drilled, and the high-voltage electrode 232C and the ground electrode 233C are protected from the rock by the drilling teeth 233B.

[0053] In order to rotate the rotor assembly 20 and, consequently, the bit 230, a fluid, such as a slurry-type fluid, is supplied to the turbine 210 by the drilling rod 2.

[0054] Subsequently, the generator 240, driven by the turbine 210, generates a charging current, which allows the capacitor of the high-frequency pulse generator 220 to be recharged through a suitable electronic circuit.

[0055] As the fluid passes through the turbine 210, it passes through the drilling motor 250, increasing the power (torque) transmitted to the bit 230 to drill the rock through rotation.

[0056] As bit 230 rotates, the cutting element 233B2 scrapes and shears the surface of the underlying rock formation. Simultaneously, the high-frequency pulse generator 220 periodically applies a voltage of, for example, 0.5 to 50 pulses per second, preferably 30 pulses per second, between the high-voltage electrode 232C and the ground electrode 233C, causing the formation of an electric arc that enables the generation of rock fragments and relieves the large mechanical stress that would have been applied to the bit to generate these rock fragments.

[0057] By penetrating the bit body 231 and opening at the central opening 231A1, the through-channel 231C allows the fluid flow to be transported within the bit body 231 so that the fluid circulates continuously around the high-voltage electrode 232C. As a result, the through-channel 231C forms a fluid screen with dielectric properties that allows an electric arc to be formed between the high-voltage electrode 232C and one of the multiple ground electrodes 233C. The fluid flow transported through the bit 230 also allows rock debris to be discharged from the drilling area to the top of the hole created by the drilling.

[0058] As the bit rotates, the ground electrode 233C has a greater tangential velocity than the high-voltage electrode 232C. The tangential velocity of the high-voltage electrode 232C is close to zero because it is located at the center of the drilling surface 231A of the bit body 231. Therefore, when a voltage is applied between the high-voltage electrode 232C and the ground electrode 233C, the fluid flow surrounding the high-voltage electrode 232C forms an effective medium that ensures the formation of an electric arc in the rock between the high-voltage electrode 232C and one of the multiple ground electrodes 233C while the bit 230 is rotating.

[0059] Thus, the fluid has two functions. Specifically, the fluid acts as a dielectric that breaks the rock by making it easier for the electric arc to pass through the rock between the fluid and the rock, and it also acts as drilling slurry that carries the rock fragments to the surface and discharges them through fluid circulation. Furthermore, the fluid flow allows for cleaning of the area between the electrodes. [Explanation of symbols]

[0060] 1: Excavation tools 2: Excavation Rod X: Rotation axis 10: Stator Assembly 20: Rotor assembly 110: Main unit 110A: Mounting end 110B: Free end 210: Turbine 220: High-power pulse generator 230 bits 231: Bit body 231A: Excavation surface 231A1: Center opening 231B: Mounting surface 231C: Through-channel 232: Exterior 232C: High-voltage electrode 233: Excavation member 233A: Fin 233B: Excavation teeth 233B1: Base 233B2: Cutting element 233C: Ground electrode 234: Groove 240: Generator 250: Excavation motor 260: Steering system 270: Tubular connection

Claims

1. A bit (230) for a drilling tool (1), The bit (230) comprises a bit body (231) having a drilling surface (231A) and a mounting surface (231B) for attaching the bit (230) to the rotor assembly (20) of the drilling tool (1), The bit body (231) has a through channel (231C) for passing a fluid flow connecting the mounting surface (231B) to the drilling surface (231A), defined by an opening in the circular central surface opening (231A1) of the drilling surface (231A). The excavation surface (231A) has an outer surface (232) that connects the central surface opening (231A1) to the mounting surface (231B), The multiple excavation members (233) evenly distributed on the outer surface (232) extend from the outer surface (232), Each of the plurality of drilling members (233) has a fin (233A) and a plurality of drilling teeth (233B) extending from the fin (233A), The fin (233A) extends radially from the outer surface (232) into the central surface opening (231A1) from the mounting surface (231B), The plurality of drilling teeth (233B) are arranged side by side between the first drilling tooth (233) located at the end of the drilling surface (231A) and the last drilling tooth (233B) located on the side of the mounting surface (231B). Each of the plurality of drilling teeth (233B) has a base (233B1) and a cutting element (233B2) positioned at the end of the base (233B1), The bit (230) has a high-voltage electrode (232C) positioned in the through channel (231C) at the center of the central surface opening (231A1) recessed from the first drilling tooth (233B) of each drilling member (233), Each of the plurality of excavation members (233) has a ground electrode (233C), The ground electrode (233C) is positioned at the end of the fin (233A) on the high-voltage electrode (232C) such that it extends at least partially along the central surface opening (231A1) recessed from the first drilling tooth (233B) of the drilling member (233), Bit (230).

2. The plurality of drilling members (233) are evenly distributed on the outer surface (232) around the bit body (231). The bit (230) according to claim 1.

3. The bit body (231) has at least three, preferably four, five, or six drilling members (233). The bit (230) according to claim 1 or 2.

4. The fin (233A) is integrally formed with the outer surface of the bit body (231). The bit (230) according to any one of claims 1 to 3.

5. The base portion (233B1) of the tooth (233B) of the drilling member (233) is integrally formed with the fin (233A) of the drilling member (233). The bit (230) according to any one of claims 1 to 4.

6. The fin (233A) extends on the outer surface (232) such that it curves in the opposite direction to the rotation of the drilling bit (230). The bit (230) according to any one of claims 1 to 5.

7. Each of the plurality of drilling members (233) has at least three, preferably four, five, or six drilling teeth (233B). The bit (230) according to any one of claims 1 to 6.

8. The base portion (233B1) has a substantially cylindrical shape that extends in a direction perpendicular to the rotation axis (X) of the bit (230). The bit (230) according to any one of claims 1 to 7.

9. The cutting element (233B2) is made of a hard, abrasive drilling material. The bit (230) according to any one of claims 1 to 8.

10. The aforementioned multiple grounding electrodes (233C) are identical, Each of the high-voltage electrode (232C) and the plurality of ground electrodes (233C) has at least a partially spherical shape. The bit (230) according to any one of claims 1 to 9.

11. Each of the electrodes (232C, 233C) has at least a partially spherical shape. Since the diameter of the high-voltage electrode (232C) is equal to at least twice the diameter of each of the plurality of ground electrodes (233C), it is possible to form an electric arc between the high-voltage electrode (232C) and any one of the plurality of ground electrodes (233C). The bit (230) according to any one of claims 1 to 10.

12. A pulse-high-power rotation drilling tool (1) comprising a stator assembly (10) and a rotor assembly (20), The stator assembly (10) is The device comprises a hollow cylindrical body (110) having a mounting end (110A) configured to be connected to the drilling rod (2) and a free end (110B), The rotor assembly (20) is Turbine (210) and, A high-power pulse generator (220), A bit (230) according to any one of claims 1 to 11, Equipped with, The turbine (210) is mounted within the main body (110) at the mounting end (110A) and is configured to be driven by the fluid flow supplied by the drilling rod (2) to rotate the rotor assembly (20). The high-power pulse generator (220) is mounted inside the main body (110) and is integrally connected to the turbine (210). The bit (230) extends from the cylindrical body (110) at the free end (110B) of the stator assembly (10). A drilling tool with pulsed high-power rotation (1).

13. The system further includes a generator (240) configured to convert the mechanical energy of a rotating turbine (210) into electrical energy in order to supply the high-power pulse generator (220), The drilling tool (1) according to claim 12.

14. The main body (110) is further equipped with a drilling motor (250) which is mounted inside the main body (110), integrally connected to the high-power pulse generator (220), and configured to be driven by the fluid flow that has passed through the turbine (210). The drilling tool (1) according to claim 12 or 13.

15. The system further includes a steering device (260) integrally connected to the bit (230), The steering device (260) is It is in the form of a hinged tube configured to receive power provided by the turbine (210) or amplified power provided by the drilling motor (250), transmit the power to the bit (230), orient the bit (230) in a predetermined direction, and transmit fluid flow from the turbine (210) to the bit (230). The drilling tool (1) according to claim 14.

Images