A dual-channel drilling tool integrating drilling, punching, and protection

Abstract

This invention provides an integrated drilling, flushing, and protection dual-channel drilling tool, comprising a centrally openable and closable drill bit, a dual-channel hydraulic flushing device, a dual-channel drill rod, and a dual-channel water supply device, connected sequentially from front to back. After drilling is completed, this invention eliminates the need to lift the drill bit or change the drilling tool; the screen pipe can be directly lowered into the central flow channel of the dual-channel drilling tool for borehole protection operations. This drilling tool has two independent flow channels, combining normal drilling, high-pressure hydraulic flushing, and full-hole screen pipe lowering for protection without lifting the drill bit. Different work tasks can be performed by connecting the water pipe to different interfaces on the dual-channel water supply device. This invention expands the application range of drilling tools, reduces the labor intensity of workers, improves drilling efficiency, and provides technical equipment support for underground gas drainage drilling in coal mines.

Description

Technical Field

[0001] This invention belongs to the technical field of underground drilling equipment in coal mines, and relates to drilling tools, specifically a dual-channel drilling tool that integrates drilling, flushing, and protection. Background Technology

[0002] To ensure safe production in coal mines, gas drainage needs to be carried out in advance in the coal seams to be mined. After drilling is completed in soft coal seams, PVC screen pipes need to be installed to protect the holes and ensure the smooth flow of gas drainage channels because the coal seams are soft and prone to collapse. At the same time, combined with hydraulic flushing pressure relief and permeability enhancement technology, the gas drainage effect can be greatly improved.

[0003] However, the current technology combining screen pipe protection and hydraulic flushing for pressure relief and permeability enhancement has the following shortcomings in actual construction:

[0004] First, the process is labor-intensive and inefficient. The most common construction method is to first perform conventional drilling accompanied by high-pressure hydraulic flushing to depressurize and enhance penetration, and then remove the drill bit to replace it with a large-diameter drill rod for full-hole screen pipe protection. This process requires lifting the drill bit once more and then lowering a special large-diameter drill bit once more. The whole process is labor-intensive and inefficient.

[0005] Secondly, the developed drilling tools are complex and prone to damage. Existing drilling tools need to achieve three working modes: low-pressure drilling, high-pressure hydraulic perforation, and screen insertion through a central flow channel. After being inserted into the hole, a high-pressure water pump is required to control the switching between different working modes, and the working state can only be determined by pressure changes. The drilling tools have a complex structure with many moving parts, making them prone to damage and rendering the functions unusable. Summary of the Invention

[0006] In view of the defects and deficiencies of the existing technology, the purpose of this invention is to provide an integrated drilling, flushing and protection dual-channel drilling tool, which solves the technical problem of high labor intensity and low efficiency in the existing technology when the drill bit needs to be lifted and the drilling tool replaced before the screen pipe is lowered during construction.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A drilling, flushing, and protection integrated dual-channel drilling tool includes a centrally openable and closable drill bit, a dual-channel hydraulic flushing tool, a dual-channel drill rod, and a dual-channel water supply device, connected sequentially from front to back.

[0009] The dual-channel hydraulic punch includes an outer tube, the front of which is connected to a central openable drill bit, and an inner tube installed in the rear of the outer tube. Both the outer and inner tubes are connected to a dual-channel drill rod. The space between the front of the outer tube and the inner tube forms the central flow channel, and the annular gap between the rear of the outer tube and the inner tube forms the annular flow channel. Multiple nozzles are fixedly mounted on the rear of the outer tube, and these nozzles are connected to the annular flow channel.

[0010] The dual-channel drill pipe includes an outer drill pipe tube, inside which an inner drill pipe tube is coaxially arranged. The axial front part of the outer drill pipe tube is connected to the outer tube of the punch of the dual-channel hydraulic punch, and the axial rear part of the outer drill pipe tube is connected to the dual-channel water supply device. The axial front part of the inner drill pipe tube is connected to the inner tube of the punch of the dual-channel hydraulic punch, and the axial rear part of the inner drill pipe tube is connected to the dual-channel water supply device. The space inside the inner drill pipe tube is the central flow channel of the drill pipe, and the annular gap between the outer drill pipe tube and the inner drill pipe tube is the annular flow channel of the drill pipe.

[0011] The dual-channel water delivery device includes a male water delivery connector. The axial front part of the male water delivery connector is installed inside the outer tube of the drill rod of the dual-channel drill rod. The axial rear part of the male water delivery connector is rotatably installed with the axial front part of the water delivery mandrel. The axial rear part of the water delivery mandrel is externally installed with a first water delivery pipe connector. The structure consisting of the male water delivery connector, the water delivery mandrel, and the first water delivery pipe connector constitutes the water delivery device housing. A water delivery device connecting pipe is provided inside the water delivery device housing. The axial front part of the connecting pipe is installed inside the inner tube of the drill rod of the dual-channel drill rod. The axial rear part of the connecting pipe is externally installed with a second water delivery pipe connector. The structure consisting of the connecting pipe and the second water delivery pipe connector constitutes the inner tube of the water delivery device. The space inside the inner tube is the central flow channel of the water delivery device. The annular gap between the outer shell and the inner tube is the annular flow channel of the water delivery device.

[0012] The space inside the centrally openable drill bit, the central flow channel of the punch, the central flow channel of the drill rod, and the central flow channel of the water supply device are connected and together form the central flow channel of the dual-channel drill bit; the annular flow channel of the punch, the annular flow channel of the drill rod, and the annular flow channel of the water supply device are connected and together form the annular flow channel of the dual-channel drill bit; the central flow channel and the annular flow channel of the dual-channel drill bit are not connected.

[0013] The present invention also has the following technical features:

[0014] The outer tube of the punch includes a main body of the outer tube, and a step of the outer tube is provided on the inner wall of the main body of the outer tube. The axial front end of the inner tube of the punch abuts against the step of the outer tube, and the axial rear end of the inner tube of the punch is flush with the axial rear end of the outer tube of the punch.

[0015] The inner tube of the punch includes a main body of the inner tube, and a step of the inner tube is provided on the inner wall of the main body of the inner tube. The axial front end of the drill rod inner tube abuts against the step of the inner tube, and the axial rear end of the drill rod inner tube is flush with the axial rear end of the drill rod outer tube.

[0016] The outer tube of the punch has multiple nozzle mounting holes on its axial rear part. The inside of the nozzle mounting holes has a stepped structure, and the punch nozzles are fixedly installed inside the nozzle mounting holes.

[0017] The dual-channel drill pipe is composed of multiple drill pipe sections; the outer tube of each drill pipe section consists of a male drill pipe connector, a main body of the drill pipe, and a female drill pipe connector from front to back. The male drill pipe connector, the main body of the drill pipe, and the female drill pipe connector are connected as one unit by friction welding; the male drill pipe connector of the outer tube of the foremost drill pipe section is installed inside the punching device outer tube, and the female drill pipe connector of the outer tube of the last drill pipe section is installed inside the water supply device male connector.

[0018] The inner wall of the drill pipe outer tube at the axial front is provided with a front step and the inner wall of the drill pipe outer tube at the axial rear is provided with a rear step. A drill pipe limiting ring is installed at the front step and the rear step of the drill pipe outer tube respectively, and the drill pipe inner tube is fixedly installed inside the drill pipe limiting ring.

[0019] Each drill pipe section consists of, from front to back, an integrated drill pipe inner tube male connector, a drill pipe inner tube body, and a drill pipe inner tube female connector, which are connected as one unit by friction welding. The drill pipe inner tube male connector of the foremost drill pipe section is inserted into the punch inner tube, and the drill pipe inner tube female connector of the last drill pipe section is inserted into the water supply device connecting pipe.

[0020] The front end face of the drill pipe inner tube female joint is the drill pipe inner tube shoulder, and the drill pipe limiting retaining ring near the axial rear side is stuck at the drill pipe inner tube shoulder.

[0021] The drill pipe limiting retaining ring includes a circular limiting retaining ring body, and multiple limiting retaining ring wing plates are integrally provided on the outside of the limiting retaining ring body. The multiple limiting retaining ring wing plates are evenly distributed along the circumferential direction of the limiting retaining ring body.

[0022] The water delivery male connector includes a water delivery male connector body, and a water delivery male connector step is provided on the inner wall of the water delivery male connector body. A water delivery limiting ring is installed at the water delivery male connector step and is sleeved on the outside of the water delivery connecting pipe.

[0023] The water delivery mandrel includes a water delivery mandrel body, and an integrally formed water delivery mandrel shoulder at the axial front end of the water delivery mandrel body; a water delivery end cap is installed at the axial rear end of the water delivery male connector, the outer diameter of the water delivery mandrel shoulder is smaller than the inner diameter of the water delivery end cap, and multiple water delivery bearings are provided between the water delivery mandrel shoulder and the water delivery end cap.

[0024] The first water pipe connector of the water delivery device includes a first water pipe connector body, and a first water pipe connector inlet is integrally provided on one radial side of the first water pipe connector body.

[0025] Multiple sealing rings are installed on the outer front part of the drill pipe inner tube, the outer front part of the water supply device connecting pipe, and the outer rear part of the water supply device connecting pipe.

[0026] Compared with the prior art, the present invention has the following beneficial technical effects:

[0027] (I) This invention eliminates the need for drill bit lifting and drill bit replacement after drilling is completed. The screen pipe can be directly lowered into the central flow channel of the dual-channel drill bit for borehole protection. The drill bit has two independent flow channels, combining normal drilling, high-pressure hydraulic flushing, and full-hole screen pipe lowering for borehole protection without drill bit lifting. Different work tasks can be performed by connecting water pipes to different interfaces on the dual-channel water supply device. This invention expands the application range of the drill bit, reduces the labor intensity of workers, improves drilling efficiency, and provides technical equipment support for underground gas drainage drilling in coal mines.

[0028] (II) The integrated drilling, flushing and protection dual-channel drilling tool of the present invention, apart from the openable and closable drill bit, has fixed relative positions of each component of the dual-channel hydraulic flushing device, dual-channel drill rod and dual-channel water supply device, with no moving parts, which greatly reduces the risk of damage during operation and enhances the structural reliability of the entire drilling tool.

[0029] (III) The use of the integrated drilling, flushing and protection dual-channel drilling tool of the present invention for hydraulic flushing and permeability enhancement operations can, on the one hand, break up and flush out a large amount of soft coal body, which can reduce the ground stress of the coal body; on the other hand, it can increase the exposed area of ​​the coal seam by forming caverns in the coal seam and form a huge fracture network around the caverns, providing a wide space for gas migration and extraction, improving the permeability of the coal seam, effectively improving the gas extraction efficiency and gas extraction volume, and eliminating the hidden dangers of mine gas disasters. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of a dual-channel drilling tool that integrates drilling, flushing, and protection.

[0031] Figure 2 This is a schematic diagram of a dual-channel hydraulic punch.

[0032] Figure 3 This is a schematic diagram of a dual-channel drill pipe.

[0033] Figure 4 This is a schematic diagram of a dual-channel water delivery system.

[0034] Figure 5 A schematic diagram of the structure of the drill pipe limiting retaining ring.

[0035] Figure 6 This is a schematic diagram of the overall structure of a dual-channel drilling tool with a screen pipe that integrates drilling, flushing, and protection.

[0036] The meanings of the labels in the diagram are as follows: 1-Center-openable and closable drill bit, 2-Dual-channel hydraulic punch, 3-Dual-channel drill rod, 4-Dual-channel water supply device, 5-Sealing ring, 6-Screen pipe suspension device, 7-Screen pipe.

[0037] 201-Outer tube of puncher, 202-Inner tube of puncher, 203-Central flow channel of puncher, 204-Annular flow channel of puncher, 205-Nose of puncher, 206-Nose mounting hole.

[0038] 301 - Outer tube of drill pipe, 302 - Inner tube of drill pipe, 303 - Central flow channel of drill pipe, 304 - Annular flow channel of drill pipe, 305 - Limiting ring of drill pipe.

[0039] 401-Water dispenser male connector, 402-Water dispenser spindle, 403-Water dispenser first water pipe connector, 404-Water dispenser connecting pipe, 405-Water dispenser second water pipe connector, 406-Water dispenser central flow channel, 407-Water dispenser annular flow channel, 408-Water dispenser limiting ring, 409-Water dispenser end cap, 410-Water dispenser bearing.

[0040] 20101 - Main body of the punching machine outer tube; 20102 - Step of the punching machine outer tube.

[0041] 20201 - Main body of the punch inner tube; 20202 - Step of the punch inner tube.

[0042] 30101-Drill pipe outer tube male connector, 30102-Drill pipe outer tube body, 30103-Drill pipe outer tube female connector, 30104-Drill pipe outer tube front step, 30105-Drill pipe outer tube rear step.

[0043] 30201-Male connector for drill pipe inner tube, 30202-Main body of drill pipe inner tube, 30203-Female connector for drill pipe inner tube, 30204-Shoulder of drill pipe inner tube.

[0044] 30501 - Limiting retainer ring body, 30502 - Limiting retainer ring wing plate.

[0045] 40101 - Male connector body for water supply unit; 40102 - Step for male connector for water supply unit.

[0046] 40201 - Water delivery mandrel body, 40202 - Water delivery mandrel shoulder.

[0047] 40301 - First water pipe connector body, 40302 - First water pipe connector inlet.

[0048] The technical solution of the present invention will be further described below with reference to the embodiments. Detailed Implementation

[0049] In this invention, "drilling-punching-protection integration" refers to the fact that the drilling tool can be used in integrated drilling operations that combine "drilling, punching, and screen pipe protection".

[0050] It should be noted that all components and devices used in this invention, unless otherwise specified, are based on parts and devices known in the art. For example: the center-openable drill bit (1) is a conventional center-openable drill bit known in the prior art. The screen pipe suspension device (6) is a conventional screen pipe suspension device known in the prior art.

[0051] Following the above technical solutions, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0052] Example:

[0053] This embodiment provides an integrated drilling, flushing, and protection dual-channel drilling tool, such as... Figure 1 As shown, it includes a centrally openable and closable drill bit 1, a dual-channel hydraulic punch 2, a dual-channel drill rod 3, and a dual-channel water supply device 4, connected sequentially from front to back.

[0054] like Figure 2 As shown, the dual-channel hydraulic punch 2 includes an outer tube 201, the axial front of which is connected to a central openable drill bit 1, and an inner tube 202 installed in the axial rear of the outer tube 201. Both the outer tube 201 and the inner tube 202 are connected to the dual-channel drill rod 3. The space in the axial front of the outer tube 201 and the space in the inner tube 202 is the central flow channel 203 of the punch, and the annular gap between the axial rear of the outer tube 201 and the inner tube 202 is the annular flow channel 204 of the punch. Multiple punch nozzles 205 are fixedly installed on the axial rear of the outer tube 201, and the punch nozzles 205 are connected to the annular flow channel 204 of the punch.

[0055] like Figure 3As shown, the dual-channel drill pipe 3 includes an outer drill pipe tube 301, and an inner drill pipe tube 302 is coaxially arranged inside the outer drill pipe tube 301. The axial front part of the outer drill pipe tube 301 is connected to the punching outer tube 201 of the dual-channel hydraulic punch 2, and the axial rear part of the outer drill pipe tube 301 is connected to the dual-channel water supply device 4. The axial front part of the inner drill pipe tube 302 is connected to the punching inner tube 202 of the dual-channel hydraulic punch 2, and the axial rear part of the inner drill pipe tube 302 is connected to the dual-channel water supply device 4. The space inside the inner drill pipe tube 302 is the drill pipe central flow channel 303, and the annular gap between the outer drill pipe tube 301 and the inner drill pipe tube 302 is the drill pipe annular flow channel 304.

[0056] like Figure 4 As shown, the dual-channel water delivery device 4 includes a male water delivery device connector 401. The axial front part of the male water delivery device connector 401 is installed inside the drill pipe outer tube 301 of the dual-channel drill pipe 3. The axial rear part of the male water delivery device connector 401 is rotatably installed with the axial front part of the male water delivery device spindle 402. The axial rear part of the male water delivery device spindle 402 is externally installed with the first water pipe connector 403. The structure composed of the male water delivery device connector 401, the male water delivery device spindle 402, and the first water pipe connector 403 constitutes the water delivery device housing. The outer casing of the device is provided with a water supply connecting pipe 404. The axial front part of the water supply connecting pipe 404 is installed in the drill pipe inner tube 302 of the double-channel drill pipe 3. The axial rear part of the water supply connecting pipe 404 is installed on the outside. The structure formed by the water supply connecting pipe 404 and the water supply second water pipe joint 405 is the inner tube of the water supply. The space inside the inner tube of the water supply is the central flow channel 406 of the water supply. The annular gap between the outer casing of the water supply and the inner tube of the water supply is the annular flow channel 407 of the water supply.

[0057] like Figure 1 As shown, the space inside the centrally openable drill bit 1, the central flow channel 203 of the punch, the central flow channel 303 of the drill rod, and the central flow channel 406 of the water supply device are connected and together form the central flow channel of the dual-channel drill bit. The central flow channel of the dual-channel drill bit has an inner flat structure with a diameter greater than or equal to 36 mm. The annular flow channel 204 of the punch, the annular flow channel 304 of the drill rod, and the annular flow channel 407 of the water supply device are connected and together form the annular flow channel of the dual-channel drill bit. The central flow channel and the annular flow channel of the dual-channel drill bit are not connected.

[0058] As one specific solution in this embodiment, such as Figure 2 As shown, the punch outer tube 201 includes a punch outer tube body 20101, and a punch outer tube step 20102 is provided on the inner wall of the punch outer tube body 20101. The axial front end of the punch inner tube 202 abuts against the punch outer tube step 20102, and the axial rear end of the punch inner tube 202 is flush with the axial rear end of the punch outer tube 201.

[0059] In this embodiment, the punch outer tube 201 is a hollow tubular structure. The space inside the punch outer tube 201 consists of two connected cylindrical cavities with different inner diameters. The cylindrical cavity at the rear of the axis has a larger inner diameter and is connected to the punch nozzle 205.

[0060] As one specific solution in this embodiment, such as Figure 2 As shown, the punch inner tube 202 includes a punch inner tube body 20201. A punch inner tube step 20202 is provided on the inner wall of the punch inner tube body 20201. The axial front end of the drill rod inner tube 302 abuts against the punch inner tube step 20202. The axial rear end of the drill rod inner tube 302 is flush with the axial rear end of the drill rod outer tube 301.

[0061] As one specific solution in this embodiment, such as Figure 2 As shown, the outer tube 201 of the punch has multiple nozzle mounting holes 206 on its axial rear portion. The interior of each nozzle mounting hole 206 has a stepped structure, and a punch nozzle 205 is fixedly installed inside the nozzle mounting hole 206. In this embodiment, the punch nozzle 205 is fixed in the nozzle mounting hole 206 by welding.

[0062] As one specific solution in this embodiment, such as Figure 3 As shown, the dual-channel drill pipe 3 is composed of multiple drill pipe sections; the drill pipe outer tube 301 of each drill pipe section consists of a drill pipe outer tube male connector 30101, a drill pipe outer tube body 30102, and a drill pipe outer tube female connector 30103 from front to back. The drill pipe outer tube male connector 30101, the drill pipe outer tube body 30102, and the drill pipe outer tube female connector 30103 are connected as one unit by friction welding; the drill pipe outer tube male connector 30101 of the foremost drill pipe section is installed inside the punch outer tube 201, and the drill pipe outer tube female connector 30103 of the last drill pipe section is installed inside the water supply male connector 401.

[0063] As one specific solution in this embodiment, such as Figure 3 As shown, a front step 30104 is provided on the inner wall of the axial front part of the drill pipe outer tube 301, and a rear step 30105 is provided on the inner wall of the axial rear part of the drill pipe outer tube 301. A drill pipe limiting ring 305 is installed at the front step 30104 and the rear step 30105 of the drill pipe outer tube, respectively. The drill pipe inner tube 302 is fixedly installed inside the drill pipe limiting ring 305.

[0064] As one specific solution in this embodiment, such as Figure 3As shown, each drill pipe section's inner tube 302 consists of an integrated drill pipe inner tube male connector 30201, a drill pipe inner tube body 30202, and a drill pipe inner tube female connector 30203, arranged sequentially from front to back. The drill pipe inner tube male connector 30201, the drill pipe inner tube body 30202, and the drill pipe inner tube female connector 30203 are connected as one unit by friction welding. The drill pipe inner tube male connector 30201 of the foremost drill pipe section is inserted into the punch inner tube 202, and the drill pipe inner tube female connector 30203 of the last drill pipe section is inserted into the water supply device connecting pipe 404.

[0065] As one specific solution in this embodiment, such as Figure 3 As shown, the front end face of the drill pipe inner tube female connector 30203 is the drill pipe inner tube shoulder 30204, and the drill pipe limiting retaining ring 305 near the axial rear side is stuck at the drill pipe inner tube shoulder 30204.

[0066] In this embodiment, the inner tube 302 of the drill pipe is fixedly connected to the outer tube 301 of the drill pipe through the drill pipe limiting retaining ring 305. When assembling the drill pipe, the female connector 30203 of the inner tube of the drill pipe is first connected to the drill pipe limiting retaining ring 305 and then locked in the female connector 30103 of the outer tube of the drill pipe. The male connector 30201 of the inner tube of the drill pipe is placed into the drill pipe limiting retaining ring 305 and then locked in the male connector 30101 of the outer tube of the drill pipe. Then, the male connector 30201 of the inner tube of the drill pipe is welded and fixed to the drill pipe limiting retaining ring 305.

[0067] As one specific solution in this embodiment, such as Figure 3 As shown, the outer wall of the drill pipe outer tube male connector 30101 is machined with a drill pipe outer tube male thread, and the inner wall of the drill pipe outer tube female connector 30103 is machined with a drill pipe outer tube female thread. The drill pipe outer tube male thread and the drill pipe outer tube female thread mesh with each other to connect the drill pipe outer tube 301 of multiple drill pipe short sections; the outer wall of the drill pipe inner tube male connector 30201 is machined with a drill pipe inner tube male thread, and the inner wall of the drill pipe inner tube female connector 30203 is machined with a drill pipe inner tube female thread. The drill pipe inner tube male thread and the drill pipe inner tube female thread mesh with each other to connect the drill pipe inner tube 302 of multiple drill pipe short sections.

[0068] As one specific solution in this embodiment, such as Figure 3 As shown, the male water supply connector 401 includes a male water supply connector body 40101. A male water supply connector step 40102 is provided on the inner wall of the male water supply connector body 40101. A water supply limiting ring 408 is installed at the male water supply connector step 40102 and is sleeved on the outside of the water supply connector connecting pipe 404. In this embodiment, the water supply connector 404 is fixedly connected to the male water supply connector 401 through the water supply limiting ring 408.

[0069] As one specific solution in this embodiment, such as Figure 4As shown, the water dispenser spindle 402 includes a water dispenser spindle body 40201, with an integrally formed water dispenser spindle shoulder 40202 at the axial front end of the water dispenser spindle body 40201; a water dispenser end cap 409 is installed at the axial rear end of the water dispenser male connector 401, the outer diameter of the water dispenser spindle shoulder 40202 is smaller than the inner diameter of the water dispenser end cap 409, and a plurality of water dispenser bearings 410 are provided between the water dispenser spindle shoulder 40202 and the water dispenser end cap 409. In this embodiment, the water dispenser end cap 409 can prevent the water dispenser bearings 410 from dislodging.

[0070] As one specific solution in this embodiment, such as Figure 4 As shown, the first water pipe connector 403 of the water supply device includes a first water pipe connector body 40301, and a first water pipe connector inlet 40302 is integrally provided on one radial side of the first water pipe connector body 40301.

[0071] As one specific solution in this embodiment, such as Figure 1 As shown, multiple sealing rings 5 ​​are installed on the outer front part of the drill pipe inner tube 302, the outer front part of the water supply device connecting pipe 404, and the outer rear part of the water supply device connecting pipe 404.

[0072] As one specific solution in this embodiment, such as Figure 5 As shown, the drill pipe limiting retaining ring 305 and the water delivery device limiting retaining ring 408 have the same structure; the drill pipe limiting retaining ring 305 includes a circular limiting retaining ring body 30501, and multiple limiting retaining ring wing plates 30502 are integrally provided on the outside of the limiting retaining ring body 30501. The multiple limiting retaining ring wing plates 30502 are evenly distributed along the circumferential direction of the limiting retaining ring body 30501.

[0073] In this embodiment, the drill pipe limiting retaining ring 305 is a three-winged plate structure with a central through hole. The diameter of its central through hole is equal to the outer diameter of the drill pipe inner tube male connector 30201. The three limiting retaining ring wings 30502 are evenly distributed at 120°. The outer diameter of the limiting retaining ring wings 30502 is equal to the inner diameter of the inner hole steps of the drill pipe outer tube male connector 30101 and the drill pipe outer tube female connector 30103.

[0074] like Figure 6 As shown, the working process of this invention is as follows:

[0075] Step 1, Drill Tool Connection: Connect the center-openable drill bit 1, the dual-channel hydraulic punch 2, the dual-channel drill rod 3, and the dual-channel water supply device 4 in sequence.

[0076] Step 2, Normal Drilling: Perform conventional gas extraction hole drilling, using a centrally openable and closable drill bit 1 for rotary drilling. Connect the water supply pipe to the second water pipe connector 405 of the water delivery device. The pump pressure is ≤2Mpa and the pump flow rate is ≤100L / min. The water flows sequentially through the central flow channel 406 of the water delivery device, the central flow channel 303 of the drill rod, and the central flow channel 203 of the punch to the centrally openable and closable drill bit 1, for cooling the drill bit and carrying away drill cuttings.

[0077] Step 3, hydraulic perforation for enhanced permeability: When drilling reaches the predetermined coal seam section, first drill forward a certain distance and then pull back a certain distance. Connect the high-pressure pump outlet pipe to the first water pipe connector 403 of the water feeder, so that the high-pressure pump pressure is ≥20Mpa and the pump flow rate is ≥200L / min. The high-pressure water flows sequentially through the annular flow channel 407 of the water feeder, the annular flow channel 304 of the drill rod, and the annular flow channel 204 of the perforator, and finally sprays out through the central flow channel of the perforator nozzle 205 to perform hydraulic perforation for enhanced permeability. Feeding and pulling operations can be performed in the coal seam section where hydraulic perforation for enhanced permeability is required to expand the length of the permeation enhancement area. When a borehole is designed with multiple hydraulic perforation for enhanced permeability sections, the above operation can be repeated.

[0078] Step 4, Lowering the screen pipe to protect the hole: After the entire hole is drilled and the hydraulic punching penetration enhancement operation is completed, turn off the high-pressure pump, disconnect the water pipe connected to the second water pipe joint 405 of the water supply device, without lifting the drill, directly lower the screen pipe 7 with the screen pipe suspension device 6 through the inner hole of the second water pipe joint 405 of the water supply device, and pass through the central flow channel 406 of the water supply device, the central flow channel 303 of the drill rod, and the central flow channel 203 of the punch in sequence. Then, push open the central wing of the central openable and closable drill bit 1 to reach the bottom of the hole. After the screen pipe 7 is pushed to the bottom of the hole, the screen pipe suspension device 6 automatically opens and hangs on the hole wall.

[0079] Step 5, Drill Removal: After the screen pipe suspension device 6 automatically opens and hooks onto the borehole wall, the dual-channel water supply device 4 can be removed, and the dual-channel drill rod 3 and dual-channel hydraulic punch 2 can be removed. The central wing of the central openable and closable drill bit 1 can be pressed down to reset for the next use. After sealing the screen pipe in the borehole, gas is extracted.

Claims

1. A dual-channel drilling tool integrating drilling, punching, and protection, characterized in that, It includes a centrally openable and closable drill bit (1), a dual-channel hydraulic punch (2), a dual-channel drill rod (3), and a dual-channel water supply device (4) connected from front to back; The dual-channel hydraulic punch (2) includes an outer tube (201), the front axial portion of which is connected to a centrally openable drill bit (1), and an inner tube (202) installed in the rear axial portion of the outer tube (201). Both the outer tube (201) and the inner tube (202) are connected to the dual-channel drill rod (3). The space inside the inner tube (202) of the punch is the central flow channel (203) of the punch, and the annular gap between the axial rear part of the outer tube (201) of the punch and the inner tube (202) of the punch is the annular flow channel (204) of the punch; multiple punch nozzles (205) are fixedly installed on the axial rear part of the outer tube (201) of the punch, and the punch nozzles (205) are connected to the annular flow channel (204) of the punch; The dual-channel drill rod (3) includes an outer drill rod tube (301) and an inner drill rod tube (302) coaxially arranged inside the outer drill rod tube (301). The front part of the outer drill rod tube (301) is connected to the punching outer tube (201) of the dual-channel hydraulic punch (2), and the rear part of the outer drill rod tube (301) is connected to the dual-channel water supply device (4). The front part of the inner drill rod tube (302) is connected to the punching inner tube (202) of the dual-channel hydraulic punch (2), and the rear part of the inner drill rod tube (302) is connected to the dual-channel water supply device (4). The space inside the inner drill rod tube (302) is the drill rod central flow channel (303), and the annular gap between the outer drill rod tube (301) and the inner drill rod tube (302) is the drill rod annular flow channel (304). The dual-channel water delivery device (4) includes a male water delivery device connector (401). The axial front part of the male water delivery device connector (401) is installed inside the drill pipe outer tube (301) of the dual-channel drill pipe (3). The axial rear part of the male water delivery device connector (401) is rotatably installed with the axial front part of the male water delivery device spindle (402). The axial rear part of the male water delivery device spindle (402) is externally installed with the first water pipe connector (403). The structure composed of the male water delivery device connector (401), the male water delivery device spindle (402), and the first water pipe connector (403) constitutes the water delivery device housing. The outer casing is provided with a water delivery device connecting pipe (404). The axial front part of the water delivery device connecting pipe (404) is installed in the drill pipe inner tube (302) of the double-channel drill pipe (3). The axial rear part of the water delivery device connecting pipe (404) is installed with a second water pipe connector (405). The structure formed by the water delivery device connecting pipe (404) and the second water pipe connector (405) is the inner tube of the water delivery device. The space inside the inner tube of the water delivery device is the central flow channel (406) of the water delivery device. The annular gap between the outer casing of the water delivery device and the inner tube of the water delivery device is the annular flow channel (407) of the water delivery device. The space within the centrally openable drill bit (1), the central flow channel (203) of the punch, the central flow channel (303) of the drill rod, and the central flow channel (406) of the water supply device are connected and together form the central flow channel of the dual-channel drill bit; the annular flow channel (204) of the punch, the annular flow channel (304) of the drill rod, and the annular flow channel (407) of the water supply device are connected and together form the annular flow channel of the dual-channel drill bit; the central flow channel and the annular flow channel of the dual-channel drill bit are not connected.

2. The integrated drilling, punching, and protection dual-channel drilling tool as described in claim 1, characterized in that, The outer tube (201) of the punch includes a body (20101) of the outer tube, and a step (20102) of the outer tube is provided on the inner wall of the body (20101). The axial front end of the inner tube (202) of the punch abuts against the step (20102) of the outer tube, and the axial rear end of the inner tube (202) of the punch is flush with the axial rear end of the outer tube (201). The inner tube (202) of the punch includes a main body (20201) of the punch, and a step (20202) of the punch is provided on the inner wall of the main body (20201). The axial front end of the drill rod inner tube (302) abuts against the step (20202) of the punch, and the axial rear end of the drill rod inner tube (302) is flush with the axial rear end of the drill rod outer tube (301).

3. The integrated drilling, punching, and protection dual-channel drilling tool as described in claim 1, characterized in that, The outer tube (201) of the puncher has multiple nozzle mounting holes (206) on its axial rear part. The nozzle mounting holes (206) have a stepped structure inside, and puncher nozzles (205) are fixedly installed inside the nozzle mounting holes (206).

4. The integrated drilling, punching, and protection dual-channel drilling tool as described in claim 1, characterized in that, The dual-channel drill pipe (3) is composed of multiple drill pipe sections; the drill pipe outer tube (301) of each drill pipe section consists of a drill pipe outer tube male connector (30101), a drill pipe outer tube body (30102), and a drill pipe outer tube female connector (30103) from front to back. The drill pipe outer tube male connector (30101), the drill pipe outer tube body (30102), and the drill pipe outer tube female connector (30103) are connected as one unit by friction welding; the drill pipe outer tube male connector (30101) of the foremost drill pipe section is installed in the punching device outer tube (201), and the drill pipe outer tube female connector (30103) of the last drill pipe section is installed with a water supply device male connector (401); The drill pipe outer tube (301) has a front step (30104) on the inner wall of the axial front part and a rear step (30105) on the inner wall of the axial rear part. A drill pipe limiting ring (305) is installed at the front step (30104) and the rear step (30105) of the drill pipe outer tube. The drill pipe inner tube (302) is fixedly installed inside the drill pipe limiting ring (305).

5. The integrated drilling, punching, and protection dual-channel drilling tool as described in claim 4, characterized in that, Each drill pipe section has an inner tube (302) consisting of an integrated drill pipe inner tube male connector (30201), a drill pipe inner tube body (30202), and a drill pipe inner tube female connector (30203) from front to back. The drill pipe inner tube male connector (30201), the drill pipe inner tube body (30202), and the drill pipe inner tube female connector (30203) are connected as one unit by friction welding. The drill pipe inner tube male connector (30201) of the foremost drill pipe section is inserted into the punch inner tube (202), and the drill pipe inner tube female connector (30203) of the last drill pipe section is inserted into the water supply device connecting pipe (404). The front end face of the drill pipe inner tube female connector (30203) is the drill pipe inner tube shoulder (30204), and the drill pipe limiting retaining ring (305) near the axial rear side is stuck at the drill pipe inner tube shoulder (30204).

6. The integrated drilling, punching, and protection dual-channel drilling tool as described in claim 4, characterized in that, The drill pipe limiting retaining ring (305) includes an annular limiting retaining ring body (30501), and multiple limiting retaining ring wing plates (30502) are integrally provided on the outside of the limiting retaining ring body (30501). The multiple limiting retaining ring wing plates (30502) are evenly arranged along the circumferential direction of the limiting retaining ring body (30501).

7. The integrated drilling, punching, and protection dual-channel drilling tool as described in claim 1, characterized in that, The water delivery male connector (401) includes a water delivery male connector body (40101), a water delivery male connector step (40102) is provided on the inner wall of the water delivery male connector body (40101), a water delivery male connector limiting ring (408) is installed at the water delivery male connector step (40102), and the water delivery male connector limiting ring (408) is sleeved on the outside of the water delivery connecting pipe (404).

8. The integrated drilling, punching, and protection dual-channel drilling tool as described in claim 7, characterized in that, The water delivery mandrel (402) includes a water delivery mandrel body (40201), and an integrally formed water delivery mandrel shoulder (40202) is provided at the axial front end of the water delivery mandrel body (40201); a water delivery end cap (409) is installed at the axial rear end of the water delivery male connector (401), the outer diameter of the water delivery mandrel shoulder (40202) is smaller than the inner diameter of the water delivery end cap (409), and a plurality of water delivery bearings (410) are provided between the water delivery mandrel shoulder (40202) and the water delivery end cap (409).

9. The integrated drilling, punching, and protection dual-channel drilling tool as described in claim 7, characterized in that, The first water pipe connector (403) of the water delivery device includes a first water pipe connector body (40301), and a first water pipe connector inlet (40302) is integrally provided on one radial side of the first water pipe connector body (40301).

10. The integrated drilling, punching, and protection dual-channel drilling tool as described in claim 7, characterized in that, Multiple sealing rings (5) are installed on the outer axial front part of the drill pipe inner tube (302), the outer axial front part of the water supply connecting pipe (404), and the outer axial rear part of the water supply connecting pipe (404).

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