Drilling tools and techniques for drilling through coal seams to create holes, eliminate spraying, and install pipes.

Abstract

This invention discloses a drilling tool for creating a cavity and eliminating gas flow in outburst-prone coal seams, along with its application position and process. The drilling tool includes an outer rod body with a drill bit at its front end. Inside the outer rod body are sequentially arranged an elimination gas flow component and a jet component. The jet component includes a jet nozzle that penetrates the outer rod body. A pressure groove for accommodating a flushing and anti-clogging component is formed on the surface of the outer rod body, and the outer edge dimension of the flushing and anti-clogging component does not exceed the outer edge dimension of the outer rod body. The advantages of this invention are: the drilling tool is relatively short, and the jet outlet is close to the drill bit, making it easy to construct a "desorption and pipe-planting cavity," and establishing a connection between the bottom of the borehole and the extraction pipe through a screen pipe; the elimination gas flow section can smoothly extract coal seam gas within the "desorption and pipe-planting cavity," and after drilling retraction, the screen pipe implanted during drilling is protected from borehole narrowing and collapse during gas extraction, which helps to extend the effective extraction time of the borehole and shorten the extraction cycle.

Description

Technical Field

[0001] This invention relates to the fields of drilling, permeability enhancement, and high-pressure gas cluster control technology for gas extraction in outburst-prone coal seams, and particularly to drilling tools, work positions, and processes for drilling through outburst-prone coal seams to create holes, eliminate gas flow, and install pipes. Background Technology

[0002] Drilling through coal seams is one of the main methods for controlling gas in outburst-prone mines. In soft, low-permeability outburst-prone coal seams, hydraulic perforation and hydraulic cavity creation are conventional techniques for increasing gas permeability in outburst-prone mines.

[0003] When drilling from rock strata into coal seams, high-pressure pumps are activated to supply high-pressure water to ejectors to create cavities for coal extraction. Due to the sealing effect of water on methane gas and the uncertainty of the amount of coal extracted under the combined influence of ground pressure and methane pressure, the rock-breach section is often sealed by water and coal slag, leading to methane blowouts. To prevent methane exceedances in cross-strata drilling blowouts, the traditional approach is to install a blowout prevention system at the borehole opening, consisting of a four-way valve, flexible hose, housing, and airbag, to minimize the leakage of methane gas from the blowout into the roadway, thus preventing blowout methane exceedance accidents. Current external blowout prevention devices play a crucial role in preventing methane from entering the roadway and threatening worker safety. However, if the blowout is severe, existing blowout prevention systems are still insufficient to prevent methane exceedance accidents. Severe blowouts can lead to damage such as leakage at the four-way valve, hose detachment, hose delamination, housing damage, and airbag rupture, thereby compromising coal mine production safety.

[0004] When drilling through gas-prone zones in outburst-prone coal seams, a series of problems frequently arise, such as difficulty in drilling to the correct depth, difficulty in inserting screen pipes, and difficulty in extracting gas, making it difficult to ensure the smooth flow of gas between the borehole and the external negative pressure extraction system. In such cases, large amounts of high-pressure gas will remain in the cavities left during hydraulic cavitation and coal extraction in the gas-prone zone. If the gas in these dense cavities is not extracted, it will form a cluster of high-pressure, loose-cavity gas pockets. With the continuous accumulation of gas energy, this can easily trigger a large-scale coal and gas outburst accident.

[0005] To address the significant outburst hazard posed by high-pressure loose-cavity gas clusters, the applicant has conducted extensive theoretical research and proposed a new technological approach to overcome this challenge: establishing a "desorption pipe-planting tunnel" near the roof and combining it with a hole-making and anti-spraying pipe-planting drill bit. Based on the concept of high-pressure loose-cavity gas clusters, a crucial conclusion is drawn: if a coal seam near the roof can be excavated using drilling tools, and a stable "desorption pipe-planting tunnel" can be established by leveraging the relative stability of the coal seam roof, coupled with a screen pipe implanted before drilling with a dual-channel drill bit, then the "desorption pipe-planting tunnel," the cavity left by hydraulic hole-making, and the external negative pressure extraction system can be interconnected through the screen pipe, achieving smooth gas extraction. This not only transforms high-pressure loose-cavity gas clusters into negative-pressure gas clusters, eliminating the outburst hazard, but also avoids situations where wet coal slag encases the screen pipe and forms a gas blockage during extraction due to borehole collapse or diameter reduction, preventing gas extraction. To address this, a hole-creation and anti-spraying pipe-planting drill bit was designed. Its jet section follows closely behind the drill bit, while the anti-spraying section is located in the center of the drill bit, which greatly facilitates the construction of the "desorption pipe-planting hole" and thus eliminates the safety hazards caused by the cluster of high-pressure loose gas bags.

[0006] To achieve the aforementioned blowout prevention method relying on the structural features of the drill bit, the applicant has applied for several related patents, mainly including "Through-Layer Drilling Extraction Drill Bit and Blowout Prevention Method for Gas Extraction While Drilling" (application number CN2022102513533.3), "Through-Layer Drilling Ring Supply Self-Clearing and Blocking Split-Type Bottom Extraction and Blowout Prevention Drill Bit" (application number CN202310838603.8), "Through-Layer Drilling Hydraulic Hole Creation and Active Blowout Prevention Integrated Drill Bit for Outburst-Prone Coal Seams" (application number CN202410340447.7), "Through-Layer Drilling Ring Supply Self-Clearing and Blocking Integrated Bottom Extraction and Blowout Prevention Drill Bit" (application number CN202310830514.9), and the matching special drill rod "High-Pressure Sealing Drill Rod for Gas Extraction While Drilling in Through-Layer Drilling of Outburst-Prone Coal Seams" (application number CN202310651841.8). From the perspective of continuous technological progress and the gradual formation of a patent protection system for spray prevention, the present invention has the following advantages over the aforementioned patents: First, the anti-spray and jet functions are integrated into a single component, and the length of this component is reduced to make it lighter and simpler.

[0007] Secondly, unlike previous integrated blowout suppression drill bits, this design features the jet in front and the blowout suppression behind. This significantly reduces the processing difficulty and cost compared to the previous design. Functionally, the jet section is close to the drill bit, making it easier to create a stable "desorption tube insertion hole" compared to other equipment or processes. At the same time, the blowout suppression section is basically located close to the jet section, which is conducive to releasing gas immediately after the formation of the "gas blockage plug" and eliminating the risk of blowout. Summary of the Invention

[0008] The purpose of this invention is to propose a drilling tool for drilling through coal seams to create holes, eliminate spraying, and install pipes, as well as its application position and process. In response to the problems existing in the prior art, a systematic design of the drilling tool has been carried out.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: A drilling tool for drilling holes and creating cavities in a coal seam to eliminate blowouts and install pipes includes an outer rod body. A drill bit is provided at the front end of the outer rod body. A blowout elimination component and a jet component are sequentially arranged inside the outer rod body. The jet component includes a jet nozzle that penetrates the outer rod body. A pressure groove for accommodating a flushing and anti-clogging component is provided on the surface of the outer rod body. The outer edge dimension of the flushing and anti-clogging component does not exceed the outer edge dimension of the outer rod body. The outer rod body and the blowout elimination assembly and jet assembly form a ring flow channel flowing towards the drill bit. The ring flow channel is connected to the jet nozzle and the flushing and anti-clogging assembly, respectively. The blowout elimination assembly is provided with a central tube insertion and exhaust channel that flows in the opposite direction to the ring flow channel.

[0010] Preferably, the anti-spray assembly includes a shaped porous tube and a first implantation tube exhaust inner tube nested within the shaped porous tube. The front end of the first implantation tube exhaust inner tube is further provided with a sealing ring for isolating the supply channel of the isolation ring and the exhaust channel of the central implantation tube. The surface of the irregularly shaped porous tube is provided with at least one protruding ridge, and multiple rows of air inlet pipes are provided on the protruding ridge, which penetrate the outer rod body and are connected to the central implantation tube exhaust channel. The end of the air inlet pipe is provided with a sieve-hole air inlet disc.

[0011] Preferably, the multi-row intake pipe includes at least one row of short intake pipes or at least one row of long intake pipes. The surface of the outer rod body is provided with at least one groove, and the groove is provided with a short pipe mounting hole that mates with the short intake pipe. The surface of the outer rod body without grooves is provided with a long pipe mounting hole that mates with the long intake pipe.

[0012] Preferably, the outer rod body has a first limiting step that cooperates with the rear end of the irregularly shaped porous tube, the irregularly shaped porous tube has a second limiting step that cooperates with the front end of the jet assembly, and the rear part of the irregularly shaped porous tube is also provided with a flushing drainage hole that communicates with the flushing anti-clogging assembly and a jet drainage hole that communicates with the jet nozzle.

[0013] Preferably, the flushing anti-clogging assembly includes a flushing cap installed in the cap groove and an enclosed check plate. The flushing cap has a diversion hole that changes the direction of water flow, and the enclosed check plate has a flushing divergence hole that disperses the water flow at the outlet of the diversion hole.

[0014] Preferably, the jet assembly further includes a second implantation tube exhaust inner tube, and a jet control slide valve and an elastic element for pushing the jet control slide valve to move are provided on the outer side of the second implantation tube exhaust inner tube, and a retaining ring is provided at both ends of the elastic element.

[0015] Preferably, the retaining ring includes a circular retaining ring located at the front end of the elastic member and a toothed retaining ring located at the rear end of the elastic member.

[0016] Preferably, a support ring is provided between the second implantation tube exhaust inner tube and the outer rod body, and a limiting ring for limiting the jet control slide valve is also provided on the second implantation tube exhaust inner tube.

[0017] Preferably, this application also discloses the operating positions of the drilling tool for drilling through coal seams to create holes, eliminate blowouts, and install pipes. Based on the aforementioned drilling tool for drilling through coal seams to create holes, eliminate blowouts, and install pipes, the operating positions are divided into the following three types: S1, Drilling Stop Position: At this time, there is no water flow in the annular flow channel. The jet control slide valve moves to contact the second limit step under the action of the elastic element and blocks the jet diversion hole. S2, Drilling and punching station: At this time, low-pressure water is introduced into the ring supply channel. The water pressure is less than the elastic force of the elastic element, so the jet control slide valve cannot be moved. The jet guide hole is still in a blocked and interrupted state. The water flows along the ring supply channel to the drill bit. At the same time, some water flows along the flushing guide hole, the redirection hole, and the flushing divergence hole to supply the flushing anti-blocking component, ensuring that the air intake pipe is unobstructed. S3, Jet Cavity Formation Station: High-pressure water is introduced into the ring supply channel at this time. The water pressure is greater than the elastic force of the elastic element, causing the jet control slide valve to move to contact the limit ring, disconnecting the ring supply channel and opening the jet diversion hole. The water flow is sprayed out along the jet diversion hole and jet nozzle to form a jet cavity. Water is no longer supplied to the drill bit. At the same time, part of the water flow flows along the flushing diversion hole, redirection hole, and flushing divergence hole to supply the flushing anti-clogging component.

[0018] Preferably, this application also discloses the usage process of a drilling tool for drilling through coal seams to create cavities, eliminate jetting, and install pipes. Based on the aforementioned usage positions of the drilling tool for drilling through coal seams to create cavities, eliminate jetting, and install pipes, when using this drilling tool to drill through coal seams, the drilling and perforation or jetting cavitation positions can be selected according to the specific conditions of the coal seam. When crossing the coal seam and reaching the roof strata, there are the following two processes: S10. If the top rock layer is soft rock, after drilling to the top rock layer, the drill bit continues to advance 0.5 meters to create a hanger receiving hole for hanging the screen pipe hanger. Then the drill bit is pulled back 0.5 meters, high-pressure water is introduced, and the drill bit enters the jet hole-making position to create a desorption tube insertion hole. After that, the screen pipe is inserted in the central tube insertion and exhaust channel, and the hanger is hung in the hanger receiving hole. S20. If the top rock layer is hard rock, the drill bit will have difficulty advancing after drilling to the top rock layer, making it impossible to drill into the top. In this case, high-pressure water can be directly introduced to allow the drill bit to enter the jet hole-making position and create a desorption tube insertion hole. Then, a screen tube is inserted into the central tube insertion and exhaust channel.

[0019] The beneficial effects of this invention are as follows: 1. This drill bit is relatively short and the jet outlet is close to the drill bit, making it easy to construct a stable "desorption pipe-planting tunnel". It also establishes a connection between the bottom of the hole and the extraction pipe through the screen pipe. The anti-spraying part can smoothly extract coal seam gas in the "desorption pipe-planting tunnel". After the drill is withdrawn, the screen pipe implanted during drilling can be protected from the effects of borehole diameter reduction and hole collapse during the gas extraction process, which is conducive to extending the effective extraction time of the borehole and shortening the extraction cycle.

[0020] 2. The jet outlet in this application is close to the drill bit to facilitate the creation of a "desorption tube insertion hole." Simultaneously, the location of the anti-blowing section is roughly adjacent to the jet outlet, which is beneficial for immediate gas discharge after the formation of a "gas-blocking plug," eliminating the risk of a blowout. Currently used drilling tools (i.e., the drilling tools mentioned in the background art of several patented technologies) all have the anti-blowing section close to the drill bit. This method only addresses how to better discharge pressurized gas after the formation of a gas-blocking plug, preventing the danger of drilling a blowout. Because the anti-blowing section in this method has a certain length, the jet outlet is also a certain distance from the drill bit. When encountering hard rock or a large drilling angle that makes it difficult to create a jacking hole, the drill jet can only create a hydraulic perforation hole, not ensuring that the roof is adjacent to this hole. In this case, over time, due to coal seam creep and ground stress, the hydraulic perforation hole may shrink or even disappear, and the screen pipe may be tightly wrapped by coal slag, losing its gas extraction function.

[0021] 3. Compared with existing drilling tools, this drilling tool has a simpler overall structure, is easier to implement, and is easier to process and install. Attached Figure Description

[0022] Figure 1 This is an overall sectional view of the drilling tool; Figure 2 This is a structural diagram of the outer rod. Figure 3 This is a structural diagram of the anti-spray assembly; Figure 4 This is a structural diagram of the cleaning component; Figure 5 for Figure 4 Structural diagram of the flushing gland; Figure 6 This is a structural diagram of the jet assembly; Figure 7 This is an assembly structure diagram of the drilling tool; Figure 8 This is a cross-sectional view of the drill bit in the stop drilling and drilling / punching positions; Figure 9 This is a cross-sectional view of the drill bit at the jet cavity creation position; Figure 10This is a diagram illustrating the application process of this drilling tool in soft rock formations on the roof. Figure 11 This is a diagram illustrating the application process of this drilling tool in hard rock strata on the top plate.

[0023] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. Detailed Implementation

[0024] The present invention will now be further described with reference to the accompanying drawings. Example

[0025] like Figure 1 , Figure 2 and Figure 7 As shown, the outburst coal seam through-layer drilling hole creation anti-spraying pipe planting drill tool of this embodiment includes an outer rod body 1. A drill bit is provided at the front end of the outer rod body 1 (not shown in the figure at the right end of the outer rod body 1). An anti-spraying component 2 and a jet component 4 are arranged sequentially inside the outer rod body 1. The jet component 4 includes a jet nozzle 48 that penetrates the outer rod body 1. A pressure groove 12 for accommodating the flushing and anti-blocking component 3 is opened on the surface of the outer rod body 1. The outer edge dimension of the flushing and anti-blocking component 3 does not exceed the outer edge dimension of the cross section of the outer rod body 1. In this way, during the rotation of the outer rod body 1, the flushing and anti-blocking component 3 can be avoided from being bumped and damaged, and it can be reliably protected. A jet nozzle mounting hole 15 for installing the jet nozzle 48 is opened on the side wall of the outer rod body 1. The jet nozzle mounting hole 15 is located at the right end of the outer rod body 1, so that the jet outlet is close to the drill bit, which facilitates the construction of the "desorption pipe planting hole".

[0026] An annular flow channel 6 is formed between the outer rod body 1, the anti-spray assembly 2, and the jet assembly 4, flowing towards the drill bit. The annular flow channel 6 is connected to the jet nozzle 48 and the flushing and anti-clogging assembly 3, respectively. The medium flowing in the annular flow channel 6 is generally water or air, used to supply the fluid for cooling the drill bit and the fluid for jet cutting the coal body. The anti-spray assembly 2 is provided with a central pipe exhaust channel 5 that flows in the opposite direction to the annular flow channel 6. The medium flowing in the central pipe exhaust channel 5 is generally methane gas from the coal seam, which is discharged from the mined coal seam.

[0027] like Figure 2As shown, in this embodiment, two grooves 11 are symmetrically provided on the outer wall of the outer rod 1. Each groove 11 contains a row of short tube mounting holes 17, and each row of short tube mounting holes includes five evenly distributed holes. In the area on the outer wall of the outer rod 1 where no grooves are provided, two rows of long tube mounting holes 18 are also symmetrically provided, and each row of long tube mounting holes also includes five evenly distributed holes. The two rows of short tube mounting holes 17 and the two rows of long tube mounting holes 18 are evenly arranged on the outer wall of the outer rod 1. In other embodiments, the number of rows of short tube mounting holes and long tube mounting holes, as well as the number of holes in each row of mounting holes, can be freely set and should also be included within the protection scope of this application.

[0028] like Figure 2 As shown, the gland groove 12 is also provided with a wire blind hole 13 and a filter screen mounting hole 14, and a first limiting step 16 is provided inside the outer rod body 1. In this embodiment, there are two gland grooves 12, located on the extension lines of the two grooves 11 (i.e., short pipe mounting holes), and the flushing and anti-clogging component 3 is installed in the gland groove 12 to flush and clean the air inlet end of the short pipe mounting hole; there are also two jet nozzle mounting holes 15, located on the extension lines of the two rows of long pipe mounting holes. Opening grooves 11 will increase the processing cost of the drill bit, and in actual construction, in most cases, coal slag will not cause complete blockage of the air inlet end; when it is completely blocked, as long as part of the blockage is cleared, the threat of gas pressure rise can be resolved. Therefore, in this embodiment, only two grooves are opened, and the flushing and anti-clogging component 3 ensures that the air inlet end of the short pipe mounting hole can be smoothly inhaled, and the air inlet end of the long pipe mounting hole is no longer cleaned.

[0029] like Figure 3 As shown, the spray elimination component 2 includes a shaped porous tube 22 and a first implantation tube exhaust inner tube 23 nested inside the shaped porous tube 22. The front end of the first implantation tube exhaust inner tube 23 is also provided with a sealing ring 21 for the isolation ring supply channel 6 and the central implantation tube exhaust channel 5. The rear end of the shaped porous tube 22 is provided with a second limiting step 224 that cooperates with the front end of the jet component 4.

[0030] In this embodiment, the surface of the irregularly shaped porous tube 22 is provided with four protruding ridges, corresponding to the aforementioned two rows of short tube mounting holes 17 and two rows of long tube mounting holes 18, respectively. Each protruding ridge has five air inlet pipe mounting step holes 221 that pass through the irregularly shaped porous tube 22, which are used to install the long air inlet pipe 25 (the end of the long air inlet pipe 25 is also provided with a screen-hole air inlet disc 34, the outer edge dimension of the screen-hole air inlet disc 34 does not exceed the outer edge dimension of the outer rod body 1) and the short air inlet pipe 24 (the end of the short air inlet pipe 24 is also provided with a screen-hole air inlet disc 34, the outer edge dimension of the screen-hole air inlet disc 34 does not exceed the outer edge dimension of the outer rod body 1). In order to reduce the impact of the air inlet pipe, its outer edge dimension does not exceed the outer edge dimension of the outer rod body 1, because the outer wall of the outer rod body 1 has a groove 11, and the corresponding two rows of air inlet pipes need to be set as short pipes. The perforated air inlet disc 34 can prevent coal slag from entering the central pipe exhaust channel 5 along the air inlet pipe. In this embodiment, the perforated air inlet disc 34 can be directly welded to the short pipe mounting hole / long pipe mounting hole.

[0031] The first implanted tube exhaust inner pipe 23 also has an air intake guide hole 231 that is concentric with and corresponds one-to-one with the air intake pipe mounting step hole 221. In other embodiments, the air intake pipe mounting step hole 221, the air intake short pipe 24, the air intake long pipe 25 and the air intake guide hole 231 may also be set to other different numbers, which should also be included within the protection scope of this application.

[0032] like Figure 4 and Figure 5 As shown, the flushing anti-clogging assembly 3 includes a flushing cap 31. The flushing cap 31 has a cap fixing step hole 311. A fastening screw 32 passes through the cap fixing step hole 311 and enters the wire blind hole 13, fixing the flushing cap 31 in the cap groove 12. A flushing water filter screen 35 and a sealing ring 36 are installed in the filter screen mounting hole 14. The flushing cap 31 also has a redirection hole 312 corresponding to the filter screen mounting hole 14, used to change the direction of media flow. The flushing anti-clogging assembly 3 also includes a surround-type check plate 33. The surround-type check plate 33 can be made of rubber and plastic and is U-shaped. The flushing cap 31 has a slot, and the two sides of the U-shaped surround-type check plate 33 can be engaged between the slot of the flushing cap 31 and the cap groove 12 to prevent shaking. Simultaneously, four flushing holes 331 are provided on the bottom plate of the U-shaped surround-type check plate 33, which can disperse the water flow at the outlet of the redirection hole 312. In the medium flowing along the annular supply channel 6, a portion of the medium can be diverted along the redirection hole 312 and then dispersed out along the flushing hole 331 to flush the inlet disc 34 of the screen, allowing the gas to flow smoothly out along the central tube exhaust channel 5. In other embodiments, the surrounding check sheet 33 can be made of other materials, and the flushing hole 331 can be set in other numbers, which should also be included within the scope of protection of this application.

[0033] like Figure 6 As shown, the jet assembly 4 also includes a second implantation tube exhaust inner pipe 41. A jet control slide valve 42 and an elastic element 44 for moving the jet control slide valve 42 are disposed on the outer side of the second implantation tube exhaust inner pipe 41. A circular retaining ring 43 is disposed at the front end of the elastic element 44, and a toothed retaining ring 45 is disposed at the rear end of the elastic element 44. In this embodiment, the elastic element 44 is a spring.

[0034] A support ring 47 is provided between the second implantation tube exhaust inner pipe 41 and the outer rod body 1. A limiting ring 46 is also provided on the second implantation tube exhaust inner pipe 41 to limit the movement of the jet control slide valve 42.

[0035] In this embodiment, the support ring 47 is fixed to the second implantation tube exhaust inner pipe 41, and the jet control slide valve 42 is sleeved on the second implantation tube exhaust inner pipe 41. The elastic element 44 is installed between the jet control slide valve 42 and the toothed retaining ring 45. The toothed retaining ring 45 is used to limit the movement of the elastic element 44. At the same time, when the jet control slide valve 42 slides backward, the rear inclined surface will contact the front inclined surface of the limiting ring 46, limiting the movement of the jet control slide valve 42 and cutting off the ring supply channel 6. The limiting ring 46 is fixedly connected to the outer rod body 1 by a convex end set screw. In this embodiment, the jet nozzle 48 has a structure with a 3mm jet channel in the middle and a threaded bottom. The elastic element 44 can only be opened when the water pressure is above 5MPa according to the pressure set by the jet cavity, which can be distinguished from the static pressure water flushing pressure in coal mines.

[0036] like Figure 3 As shown, the irregularly shaped porous tube 22 has a second limiting step 224 that limits the leftward movement of the jet control slide valve 42 (the limiting ring 46 limits the rightward movement of the jet control slide valve 42). The rear of the irregularly shaped porous tube 22 also has a flushing guide hole 222 connected to the flushing anti-clogging component 3 and a jet guide hole 223 connected to the jet nozzle 48. The jet guide hole 223 is a stepped hole, and its central channel is connected to the central channel of the jet nozzle 48, supplying fluid under jetting conditions. The flushing guide hole 222 is a through hole, connected to the flushing water diversion hole 312. Under jetting and drilling conditions, the fluid passes through the flushing guide hole 222, is filtered by the filter screen 35, and then enters the flushing water diversion hole 312. Finally, it flushes the blockage on the air inlet screen 34 through the flushing divergence hole 331 on the surrounding check plate 33. The sealing ring 36 seals the two interfaces.

[0037] The first limiting step 16 inside the outer rod 1 is used to cooperate with the rear end of the irregular porous tube 22 to position the installation of the spray-dissipating component 2.

[0038] Based on the aforementioned drilling tool for drilling through coal seams to create cavities, eliminate blowouts, and install pipes, this embodiment also discloses the operating positions for the drilling tool for drilling through coal seams to create cavities, eliminate blowouts, and install pipes. The operating positions are divided into the following three types: S1, Drilling Stop Position, such as Figure 8 As shown, there is no water flow in the ring supply channel 6 at this time, and the jet control slide valve 42 moves to contact the second limit step 224 under the action of the elastic element 44 (as shown). Figure 3 As shown, a sealing slope that cooperates with the jet control slide valve 42 is also provided at the step, and the jet diversion hole 223 is blocked to prevent the drilling slag from entering the drill bit.

[0039] S2, Drilling and punching station, such as Figure 8 As shown, at this time, low-pressure water is introduced into the ring supply channel 6. The water pressure is less than the elastic force of the elastic element 44, so the jet control slide valve 42 cannot be moved. The jet diversion hole 223 is still in a blocked and interrupted state. The water flows along the ring supply channel 6 to the drill bit. At the same time, part of the water flows along the flushing diversion hole 222, the redirection hole 312, and the flushing divergence hole 331 to supply the flushing anti-blocking component 3, flushing the blockage on the air intake screen mesh 34 and ensuring that the air intake pipe is unobstructed.

[0040] S3, jet-assisted cavity creation station, such as Figure 9 As shown, high-pressure water is introduced into the ring supply channel 6 at this time. The water pressure is greater than the elastic force of the elastic element 44, causing the jet control slide valve 42 to move to contact the limit ring 46, disconnecting the ring supply channel 6 and opening the jet guide hole 223. The water flows out along the jet guide hole 223 and the jet nozzle 48 to create a jet cavity, and no longer supplies water to the drill bit. At the same time, part of the water flows along the flushing guide hole 222, the redirection hole 312, and the flushing divergence hole 331 to supply the flushing anti-blocking component 3 and flush the blockage on the air inlet screen mesh 34.

[0041] Regarding the aforementioned Figure 8 and Figure 9 It is important to note that Figure 8 In the middle, the cross-section is a cross-sectional view taken along the long intake pipe 25. Figure 9 In the middle, the cross-section is a cross-sectional view taken along the intake short pipe 24.

[0042] Based on the aforementioned operating positions of the drilling tool for drilling through coal seams to create cavities and eliminate jetting during pipe installation, this embodiment also discloses the operating process of the drilling tool for drilling through coal seams to create cavities and eliminate jetting during pipe installation. When using this drilling tool to drill through coal seam 77, the drilling and perforation or jetting cavitation positions can be selected according to the specific conditions of coal seam 77. This is an existing conventional technology and will not be described in detail in this embodiment. When crossing coal seam 77 and reaching the roof stratum 74, depending on the hardness of the roof stratum 74, there are the following two processes: During construction, the drill bit extends upwards from roadway 81, successively passing through the floor strata 78 and coal seam 77 until the drill bit contacts the roof strata 74. After penetrating coal seam 77, the required oil pressure of the drilling rig will increase significantly, and the drill bit's advance distance can be displayed in real time on the control device. When the drill bit passes through coal seam 77, it will perform hydraulic perforation. Hydraulic perforation is a conventional method in coal seam gas hydraulic permeability enhancement technology. The drill bit performs hydraulic perforation during the process of penetrating the coal seam (or during the retraction process), forming a hydraulic perforation hole 72 in the process. These are all existing conventional technologies and will not be described in detail in this embodiment.

[0043] S10, such as Figure 10 As shown, if the roof stratum 74 is soft rock, after drilling to the roof stratum 74, the drill bit continues to advance 0.5 meters to create a hanger receiving hole 79 for hanging the screen pipe hanger. Then, the drill bit retracts 0.5 meters, the high-pressure pump is turned on, and high-pressure water is introduced to allow the drill bit to enter the jet cavity creation position and create a desorption pipe planting hole 71. The lower part of the desorption pipe planting hole 71 is the coal seam 77, and the upper part is the roof stratum 74. There is no need to worry about the screen holes being buried or blocked due to coal seam collapse. Afterwards, the screen pipe 751 is inserted into the central pipe planting and exhaust channel 5, and the hanger 752 is hung in the hanger receiving hole 79. At this time, the part with the screen holes at the top of the screen pipe 751 will be protected by the roof stratum 74 and will not be buried or blocked by the collapsed coal body. The screen holes can be fully exposed to the gas.

[0044] S20, such as Figure 11 As shown, if the top rock layer 74 is hard rock, the drill bit will have difficulty advancing after drilling to the top rock layer 74. When the contact angle between the drill bit and the top rock layer 74 is too large, the drill bit will slip and the top rock layer cannot be drilled. At this time, high-pressure water can be directly introduced to allow the drill bit to enter the jet hole-making position and create a desorption tube insertion hole 71. Then, a screen tube 751 is inserted into the central tube insertion and exhaust channel 5. Because the jet outlet of the drill bit follows the drill bit, it ensures that the desorption pipe-planting hole 71 is protected by the roof rock layer 74 and will not collapse. The large space makes it difficult for the screen pipe 751 to shrink and get stuck, so that the screen hole is also fully exposed to the gas. This avoids the collapse of the hole after the drill is withdrawn, which would cause the coal-water mixture 73 to block the screen hole (the coal-water mixture 73 after the drill is withdrawn will generally not completely occupy the hydraulic flushing hole 72, leaving a certain space. However, over time, due to the creep of the coal body and the effect of ground stress, the hydraulic flushing hole 72 may shrink or even disappear. This is the reason for the design of the desorption pipe-planting hole 71 in this patent), which would affect gas extraction.

[0045] In the aforementioned process, a reliable investigation of the geological conditions related to the coal seam is required before construction. Whether the roof stratum 74 is hard or soft rock can be considered a known condition. Furthermore, during actual construction, the hardness of the local roof stratum 74 may change. In this case, a combination of steps S10 and S20 can be used, for example: Figure 10 or Figure 11 As shown, in the pipe installation extending from the same tunnel, some pipe installation points adopt the S10 process (the drill bit can continue to advance after contacting the roof rock layer 74), while some pipe installation points adopt the S20 process (the drill bit cannot continue to advance after contacting the roof rock layer 74). This embodiment will not be described in detail.

[0046] After the pipe insertion is completed, the drill is withdrawn (the drill bit and drill rod are withdrawn together from the drilled hole), and the hole is sealed (each hole needs to be sealed with a sealing device 76 after withdrawal. The sealing device 76 is annular, with the inner ring wrapping around the screen pipe 751, and the outer wall completely adhering to the hole wall to prevent gas from escaping from the hole or rock crevices into the roadway and causing danger), and the extraction connecting pipe is connected. At this time, the desorption pipe insertion hole 71 at the bottom of the hole and the extraction connecting pipe outside the hole are connected, forming an extraction passage that runs through the hole. Gas extraction will no longer be affected by factors such as hole collapse, hole shrinkage, or hole blockage that block the screen hole. The sealing device 76 and the extraction connecting pipe are all existing conventional components, and will not be described in detail in this embodiment.

[0047] The above embodiments are not intended to limit the shape, material, structure, etc. of the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of this invention and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0049] If the terms "first" or "second" are used in this document to define components, those skilled in the art should know that the use of "first" or "second" is merely for the convenience of describing the invention and simplifying the description, and unless otherwise stated, the above terms have no special meaning.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A drilling tool for drilling through coal seams to create cavities, eliminate spraying, and install pipes, comprising an outer rod body (1), wherein a drill bit is provided at the front end of the outer rod body (1), characterized in that: The outer rod (1) is provided with a spray-dissipating component (2) and a jet component (4) in sequence. The jet component (4) includes a jet nozzle (48) that penetrates the outer rod (1). The surface of the outer rod (1) is provided with a pressure groove (12) for accommodating the flushing anti-clogging component (3). The outer edge dimension of the flushing anti-clogging component (3) does not exceed the outer edge dimension of the cross section of the outer rod (1). The outer rod body (1) and the anti-spray assembly (2) and jet assembly (4) form a ring supply channel (6) that flows in the direction of the drill bit. The ring supply channel (6) is connected to the jet nozzle (48) and the flushing and anti-clogging assembly (3) respectively. The anti-spray assembly (2) is provided with a central tube insertion exhaust channel (5) that flows in the opposite direction to the ring supply channel (6).

2. The drilling tool for drilling through coal seams to create holes, eliminate blowouts, and install pipes according to claim 1, characterized in that, The anti-spray assembly (2) includes a shaped porous tube (22) and a first implantation tube exhaust inner tube (23) nested inside the shaped porous tube (22). The front end of the first implantation tube exhaust inner tube (23) is also provided with a sealing ring (21) for the isolation ring supply channel (6) and the central implantation tube exhaust channel (5). The surface of the irregular porous tube (22) is provided with at least one protruding ridge, and multiple air inlet pipes are provided on the protruding ridge, which penetrate the outer rod body (1) and are connected to the central implantation tube exhaust channel (5). The end of the air inlet pipe is provided with a sieve-hole air inlet disc (34).

3. The drilling tool for drilling through coal seams to create holes, eliminate spraying, and install pipes according to claim 2, characterized in that, The multi-row intake pipe includes at least one row of short intake pipes (24) or at least one row of long intake pipes (25). The surface of the outer rod body (1) is provided with at least one groove (11). The groove (11) is provided with a short pipe mounting hole (17) that mates with the short intake pipe (24). The surface of the outer rod body (1) without grooves is provided with a long pipe mounting hole (18) that mates with the long intake pipe (25).

4. The drilling tool for drilling through coal seams to create holes, eliminate blowouts, and install pipes according to claim 3, characterized in that, The outer rod body (1) has a first limiting step (16) that cooperates with the rear end of the irregular porous tube (22), the irregular porous tube (22) has a second limiting step that cooperates with the front end of the jet assembly (4), and the rear part of the irregular porous tube (22) is also provided with a flushing drainage hole (222) that communicates with the flushing anti-blocking assembly (3) and a jet drainage hole (223) that communicates with the jet nozzle (48).

5. The drilling tool for drilling through coal seams to create holes, eliminate spraying, and install pipes according to claim 4, characterized in that, The flushing anti-clogging component (3) includes a flushing cap (31) installed in the cap groove (12) and a surrounding check plate (33). The flushing cap (31) has a diversion hole (312) for changing the direction of water flow, and the surrounding check plate (33) has a flushing divergence hole (331) for diverting the water flow at the outlet of the diversion hole (312).

6. The drilling tool for drilling through coal seams to create holes, eliminate spraying, and install pipes according to claim 5, characterized in that, The jet assembly (4) also includes a second implantation tube exhaust inner tube (41), and a jet control slide valve (42) and an elastic element (44) for pushing the jet control slide valve (42) to move are provided on the outside of the second implantation tube exhaust inner tube (41). Both ends of the elastic element (44) are provided with retaining rings.

7. The drilling tool for drilling through coal seams to create holes, eliminate blowouts, and install pipes according to claim 6, characterized in that, The retaining ring includes a circular retaining ring (43) located at the front end of the elastic member (44) and a toothed retaining ring (45) located at the rear end of the elastic member (44).

8. The drilling tool for drilling through coal seams to create holes, eliminate spraying, and install pipes according to claim 7, characterized in that, A support ring (47) is provided between the second implantation tube exhaust inner tube (41) and the outer rod body (1), and a limiting ring (46) is also provided on the second implantation tube exhaust inner tube (41) to limit the jet control slide valve (42).

9. A work station for using a drilling tool for drilling through layers of outburst-prone coal seams to create cavities, eliminate blowouts, and install pipes, based on the drilling tool for drilling through layers of outburst-prone coal seams to create cavities, eliminate blowouts, and install pipes as described in claim 8, characterized in that... The workstations are divided into the following three types: S1, Drilling stop position, at this time there is no water flow in the ring supply channel (6), the jet control slide valve (42) moves to contact the second limit step under the action of the elastic element (44) and blocks the jet diversion hole (223). S2, Drilling and punching station. At this time, low-pressure water is introduced into the ring supply channel (6). The water pressure is less than the elastic force of the elastic element (44), so the jet control slide valve (42) cannot be moved. The jet guide hole (223) is still in the blocked state. The water flows along the ring supply channel (6) to the drill bit. At the same time, some water flows along the flushing guide hole (222), the redirection hole (312), and the flushing divergence hole (331) to supply the flushing anti-blocking component (3) to ensure that the air intake pipe is unobstructed. S3, jet cavitation station. At this time, high-pressure water is introduced into the ring supply channel (6). The water pressure is greater than the elastic force of the elastic element (44), causing the jet control slide valve (42) to move to contact the limit ring (46), disconnecting the ring supply channel (6) and opening the jet guide hole (223). The water flow is sprayed out along the jet guide hole (223) and the jet nozzle (48) to perform jet cavitation. Water is no longer supplied to the drill bit. At the same time, part of the water flow flows along the flushing guide hole (222), the redirection hole (312), and the flushing divergence hole (331) to supply the flushing anti-blocking component (3).

10. The application process of a drilling tool for drilling through layers of outburst-prone coal seams to create cavities, eliminate blowouts, and install pipes, based on the application station of the drilling tool for drilling through layers of outburst-prone coal seams as described in claim 9, is characterized in that... When using this drill bit to drill through the coal seam (77), the drilling and perforation or jet hole-making positions can be selected according to the specific conditions of the coal seam (77). When crossing the coal seam (77) and reaching the roof strata (74), there are the following two processes: S10. If the top rock layer (74) is soft rock, after drilling to the top rock layer (74), the drill bit continues to advance 0.5 meters to create a hanging device receiving hole (79) for hanging screen pipe hangers. Then the drill bit retreats 0.5 meters, high-pressure water is introduced, and the drill bit enters the jet hole-making position to create a desorption tube planting hole (71). After that, screen pipe (751) is implanted in the central tube planting and exhaust channel (5), and the hanger (752) is hung in the hanging device receiving hole (79). S20. If the top rock layer (74) is hard rock, after drilling to the top rock layer (74), the drill bit will have difficulty advancing, making it impossible to drill into the top rock layer. At this time, high-pressure water can be directly introduced to allow the drill bit to enter the jet hole-making position and create a desorption tube-planting hole (71). Then, a screen tube (751) is implanted in the central tube-planting exhaust channel (5).

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