Method for improving gas extraction concentration of crossing drill hole
By detecting and adjusting gas extraction parameters, unblocking flow channels and sealing leaky channels, the problem of poor gas extraction effect of coal mines is solved, and efficient gas extraction and resource utilization are achieved.
Patent Information
- Application Number
- CN202510742058.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-05
- Publication Date
- 2025-07-08
AI Technical Summary
In the prior art, coal mine gas extraction effect is poor, resulting in large gas outflow, inability to be effectively utilized, and low extraction concentration, serious waste of resources, and problems such as loose sealing materials, crack leakage and blockage of flow channels.
By detecting the gas concentration at the drilling hole and the bottom of the hole, unblocking the gas flow channel, adjusting the extraction pressure, sealing the leakage channel, using pressure circulation and sealing liquid to seal the gas leakage channel, optimize the extraction parameters to improve the gas extraction concentration.
The gas extraction concentration is increased, resource waste is reduced, and the extraction cycle is extended, achieving efficient gas extraction effect.
Smart Images
Figure CN120273665A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of coal mine gas control, and particularly to a method for improving the gas drainage concentration of cross - seam boreholes. Background Technique
[0002] Gas is a killer threatening the lives of coal miners, and at the same time, it is a clean energy source. Draining and utilizing gas can fundamentally prevent potential gas outbursts or explosions, promote the safe production of coal mines, increase the supply of clean energy, reduce greenhouse gas emissions, protect the environment, and effectively achieve the goal of energy conservation and emission reduction, with far - reaching social benefits. The coal output of high - gas mines and coal - and - gas outburst mines in the main coal - producing provinces (autonomous regions, municipalities) of the country accounts for about 1 / 3 of the total national coal output.
[0003] Due to the large amount of gas emission, many mines cannot effectively solve the gas emission during normal production only by ventilation means, and gas drainage work must be carried out. Moreover, the occurrence conditions of coal seams in China are relatively complex, and the coal seam permeability is relatively low. There are generally problems of great difficulty in coal mine gas drainage and poor drainage effect. The reasons for this situation are various: during the process of drilling drainage holes, after the hole sealing is completed and the drainage starts, since the hole - sealing material is solidified cement slurry, which belongs to hard - material hole - sealing, the sealed section is inevitably affected by the combined action of the loose circle of roadway surrounding rock and ground stress. As the drainage time prolongs, the cracks around the borehole continuously develop, forming air - leakage channels, causing outside air to easily enter the drainage borehole under the action of drainage negative pressure, thus resulting in a decrease in the gas drainage concentration; on the other hand, due to the influence of drainage negative pressure and fissure water, the gas flow channel is easily blocked by wet coal mud, thereby reducing the gas drainage concentration; in addition, the drainage negative pressure has a significant impact on the gas concentration and flow rate of the drainage borehole. Too low negative pressure will cause gas to be difficult to drain out of the coal seam, while too high negative pressure will cause a large amount of air to enter the drainage borehole along the cracks around the borehole, also reducing the drainage effect. The gas drained with too low concentration fails to meet the industrial utilization standard and is forced to be discharged into the atmosphere, which not only increases the greenhouse effect but also represents a great waste of resources.
[0004] In summary, it is particularly important to solve the problems of low drainage concentration and long drainage cycle caused by unreasonable drainage pressure, blockage of gas flow channels, and the existence of cracks in the flow channels during the drainage process of regional gas control boreholes. Summary of the Invention
[0005] In order to solve the problem of poor existing gas drainage effect, this application provides a method for improving the gas drainage concentration of cross - seam boreholes.
[0006] An embodiment of the present invention provides a method for increasing the gas drainage concentration of cross - seam boreholes, including: if the gas concentration at the orifice of the borehole is lower than the first threshold, detecting the gas concentration at the bottom of the borehole; determining whether the gas flow channel is blocked and dredging the gas flow channel according to the comparison result between the gas concentration at the bottom of the borehole and the second threshold; if the gas concentration at the bottom of the borehole is higher than the second threshold, adjusting the gas drainage pressure in the borehole and detecting the gas concentration at the orifice of the borehole; determining whether there is a gas leakage channel and blocking the gas leakage channel according to the comparison result between the gas concentration at the orifice of the borehole and the third threshold.
[0007] In a specific implementation, the determining whether the gas flow channel is blocked and dredging the gas flow channel according to the comparison result between the gas concentration at the bottom of the borehole and the second threshold includes: if the gas concentration at the bottom of the borehole is lower than the second threshold, performing more than one pressure cycle on the borehole to dredge the gas flow channel; the pressure cycle is injecting compressed gas into the borehole, after reaching the preset pressure and maintaining the pressure for the preset time, then discharging the pressure of the borehole at the preset speed; after dredging the gas flow channel, if the gas concentration at the bottom of the borehole is still lower than the second threshold, plugging the borehole.
[0008] In a specific implementation, the determining whether there is a gas leakage channel and blocking the gas leakage channel includes: collecting the gas at the sampling position of the borehole at the second drainage pressure under the first drainage pressure of the borehole, where the second drainage pressure is less than the first drainage pressure; monitoring the gas concentration of the collected sampling position; determining the position of the gas leakage channel according to the gas concentration of the sampling position; blocking the gas leakage channel.
[0009] In a specific implementation, the sampling position includes at least one of the following: the bottom of the borehole, the middle of the borehole, the orifice of the borehole, the combined position of the coal seam and the rock stratum in the borehole.
[0010] In a specific implementation, the determining the position of the gas leakage channel according to the gas concentration of the sampling position includes: if the gas concentration from the target position in the sampling position to the bottom of the borehole increases, and the gas concentration from the orifice of the borehole to the target position decreases, then determining that the target position is the position of the gas leakage channel.
[0011] In a specific embodiment, the blocking of the air leakage channel includes: arranging a guiding pipe in the gas drainage pipe of the borehole, wherein the enclosed cross-section between the first end of the guiding pipe close to the borehole orifice and the first end of the gas drainage pipe close to the borehole orifice is sealed; injecting a sealing liquid into the enclosed cavity between the gas drainage pipe and the guiding pipe; pressurizing the enclosed cavity through the guiding pipe so that the sealing liquid closes the air leakage channel.
[0012] In a specific embodiment, after arranging the guiding pipe in the gas drainage pipe of the borehole, it further includes: arranging a sealing device at the first end of the gas drainage pipe close to the borehole orifice; blocking the enclosed cross-section between the first end of the guiding pipe close to the borehole orifice and the first end of the gas drainage pipe close to the borehole orifice.
[0013] In a specific embodiment, the injecting of the sealing liquid into the enclosed cavity between the gas drainage pipe and the guiding pipe includes: injecting the sealing liquid into the enclosed cavity between the gas drainage pipe and the guiding pipe through the sealing device, wherein the second end of the guiding pipe extends deep into the coal seam position in the borehole.
[0014] In a specific embodiment, after determining whether there is an air leakage channel and blocking the air leakage channel according to the comparison result between the gas concentration at the orifice of the borehole and a third threshold, the method further includes: connecting the borehole to a gas drainage system; detecting the gas drainage parameters of the borehole, where the gas drainage parameters include at least one of the following: gas drainage flow rate and gas concentration; determining the gas drainage pressure of the borehole according to the gas drainage parameters.
[0015] The method for improving the gas drainage concentration of cross-layer boreholes provided by the embodiments of the present invention detects the gas concentration at the bottom of the borehole when the gas concentration at the orifice of the borehole is lower than a first threshold; and then determines whether the gas flow channel is blocked and dredges the gas flow channel according to the comparison result between the gas concentration at the bottom of the borehole and a second threshold; if the gas concentration at the bottom of the borehole is higher than the second threshold, adjust the gas drainage pressure in the borehole and detect the gas concentration at the orifice of the borehole; then determine whether there is an air leakage channel and block the air leakage channel according to the comparison result between the gas concentration at the orifice of the borehole and a third threshold. This method reduces resource waste and improves the gas drainage effect by detecting gas drainage parameters, dredging the gas flow channel, blocking the gas leakage channel, and adjusting the gas drainage pressure. Description of the Drawings
[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0017] Figure 1 It is a flowchart of a method for improving the gas drainage concentration of cross - layer boreholes provided by an embodiment of the present application; Figure 2 It is a schematic summary diagram of the process of a method for improving the gas drainage concentration of cross - layer boreholes provided by an embodiment of the present application. Specific embodiments
[0018] The following will describe the embodiments of the present invention in detail with reference to the drawings.
[0019] It should be clear that the described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.
[0020] In order to solve the problems of low drainage concentration and long drainage period caused by unreasonable drainage pressure, blocked gas flow channels, and cracks in the flow channels during the drainage process of regional gas control boreholes, as Figure 1 shown, an embodiment of the present invention provides a method for improving the gas drainage concentration of cross - layer boreholes, and the method may include: S11. If the gas concentration at the orifice of the borehole is lower than the first threshold, detect the gas concentration at the bottom of the borehole.
[0021] During the drainage process, when it is detected that the gas concentration at the orifice of the borehole is relatively low, for example, lower than the first threshold, the gas concentration at the bottom of the borehole can be further detected for further analysis and judgment. The first threshold can be determined according to the empirical value of gas drainage or through experimental analysis. When detecting the gas concentration at the bottom of the borehole, under the normal drainage state of the borehole, with the help of the underground compressed air system to provide power, a sampling negative pressure lower than the gas drainage negative pressure is generated through a negative pressure ejector, and the gas at the bottom of the borehole is sampled and extracted through the sampling gas pipe and sent into the gas collecting chamber of an optical gas detector to measure the gas concentration at the bottom of the borehole.
[0022] S12. Determine whether the gas flow channel is blocked according to the comparison result between the gas concentration at the bottom of the borehole and the second threshold, and dredge the gas flow channel.
[0023] If the gas concentration at the bottom of the borehole is relatively low, there may be two situations: one is that after a long-term gas drainage through this borehole, the gas in the coal seam around the borehole has been fully desorbed, and the gas concentration has naturally decreased, indicating that this coal seam no longer poses an outburst risk; the other is that the gas flow channel is blocked by coal slime, and the gas in the coal seam cannot be desorbed into the borehole. For the second situation, it is necessary to dredge the gas flow channel. Therefore, after measuring the gas concentration at the bottom position of the borehole, the gas concentration at the bottom position can be compared with the second threshold value to analyze and determine whether the gas flow channel is blocked and whether it is necessary to dredge the gas flow channel. The second threshold value can also be determined based on the empirical values of gas drainage or through experimental analysis.
[0024] S13. If the gas concentration at the bottom of the borehole is higher than the second threshold value, adjust the gas drainage pressure in the borehole and detect the gas concentration at the orifice of the borehole.
[0025] If the gas concentration at the bottom of the borehole is higher than the second threshold value while the concentration at the orifice is relatively low, first, according to the actual conditions of the mine, moderately adjust the gas drainage pressure and detect the gas concentration at the orifice of the borehole to test the drainage effect. For example, if the negative pressure for gas drainage is increased and the drainage concentration correspondingly increases, then this borehole can be connected to the network for drainage.
[0026] S14. Based on the comparison result between the gas concentration at the orifice of the borehole and the third threshold value, determine whether there is a gas leakage channel and block the gas leakage channel.
[0027] After adjusting the gas drainage pressure, if the gas concentration at the orifice of the borehole does not reach the third threshold value, that is, the gas drainage concentration in the borehole has not increased, it is considered that there are gas leakage cracks in the sealed section of the borehole. It is necessary to detect the location of the gas leakage channel and block it. Similarly, the third threshold value can also be determined based on the empirical values of gas drainage or through experimental analysis. The third threshold value can be the same as or different from the value of the first threshold value.
[0028] The method for improving the gas drainage concentration of cross - seam boreholes provided by the embodiments of the present invention includes: when the gas concentration at the orifice of the borehole is lower than the first threshold value, detecting the gas concentration at the bottom of the borehole; then, based on the comparison result between the gas concentration at the bottom of the borehole and the second threshold value, determining whether the gas flow channel is blocked and dredging the gas flow channel; if the gas concentration at the bottom of the borehole is higher than the second threshold value, adjusting the gas drainage pressure in the borehole and detecting the gas concentration at the orifice of the borehole; and then, based on the comparison result between the gas concentration at the orifice of the borehole and the third threshold value, determining whether there is a gas leakage channel and blocking the gas leakage channel. This method reduces resource waste and improves the gas drainage effect by detecting gas drainage parameters, dredging the gas flow channel, blocking the gas leakage channel, and adjusting the gas drainage pressure.
[0029] Optionally, in an embodiment of the present invention, step S12 determines whether the gas flow channel is blocked and dredges the gas flow channel according to the comparison result between the gas concentration at the bottom of the drill hole and the second threshold, including: if the gas concentration at the bottom of the drill hole is lower than the second threshold, performing more than one pressure cycle on the drill hole to dredge the gas flow channel; the pressure cycle is to inject compressed gas into the drill hole, and after reaching the preset pressure and maintaining the pressure for the preset time, then depressurize the drill hole at the preset speed; after dredging the gas flow channel, if the gas concentration at the bottom of the drill hole is still lower than the second threshold, block the drill hole.
[0030] When performing the pressure cycle on the drill hole, the connection between the drill hole and the gas drainage system can be disconnected first, the drill hole gas drainage pipe is connected to the air pressurization device, and compressed gas is injected into the gas drainage drill hole. After the coal body around the drill hole reaches adsorption equilibrium, sudden depressurization is performed, so that a phase change field of "adsorption-desorption" of gas in the coal body around the drill hole occurs, and the coal body undergoes an alternating stress field of "expansion-contraction-destruction". During the process of coal body expansion and contraction, the stress and strain states change, resulting in a change in the gas permeability of the coal. Relying on the cyclic action of high-pressure gas, an air dynamic field of "pressurization-depressurization-scouring" is established in the gas drainage drill hole, and the plugging material in the drill hole is pressurized and depressurized for several cycles, such as 15-20 cycles, to flush out the pulverized coal and accumulated water in the gas drainage drill hole and the surrounding coal seam fractures, and the plugging material in the gas seepage channel is cleaned, and the gas flow channel is dredged.
[0031] After dredging the gas flow channel, if the gas concentration at the bottom of the drill hole is still lower than the second threshold, it indicates that the gas in the coal seam around the drill hole has been fully desorbed after a long time of gas drainage, and the gas concentration has naturally decreased, and the drill hole can be blocked.
[0032] Optionally, in an embodiment of the present invention, in step S14, determining whether there is a gas leakage channel and blocking the gas leakage channel includes: collecting gas at the sampling position of the drill hole at the second gas drainage pressure under the first gas drainage pressure of the drill hole, where the second gas drainage pressure is less than the first gas drainage pressure; monitoring the gas concentration at the sampled position; determining the position of the gas leakage channel according to the gas concentration at the sampled position; blocking the gas leakage channel. The sampling positions include at least one of the following: the bottom of the drill hole, the middle of the drill hole, the orifice of the drill hole, and the combined position of the coal seam and the rock stratum in the drill hole. The combined position of the coal seam and the rock stratum in the drill hole, that is, the combined position of the screen pipe and the solid pipe of the gas drainage pipe in the drill hole, where the end of the screen pipe of the gas drainage pipe is provided with ventilation holes.
[0033] If the drilling hole is well sealed and airtight, under the action of the drainage negative pressure, the gas concentration in the drilling hole is stable and basically the same along the depth of the drilling hole; if there is air leakage at a certain position inside the drilling hole, under the action of the drainage negative pressure, the distribution of the gas concentration in the drilling hole will show a sudden change. The gas concentration from the hole mouth of the drilling hole to the air leakage position will decrease sharply, while the gas concentration in the area from the air leakage position to the bottom of the drilling hole is relatively high; in the normal drainage state of the drilling hole, the power can be provided by the underground compressed air system, and a collection negative pressure lower than the drainage negative pressure can be generated by the negative pressure ejector. The gas at the specified sampling position of the drilling hole is pumped out through the gas extraction pipe and then sent into the gas collection chamber of the optical gas detector to detect the gas concentration of the gas sample at the sampling position. By measuring the gas concentration at different depths in the drilling hole, the distribution change law of the gas concentration and the air leakage amount along the depth of the drilling hole is analyzed to determine the sealing quality and the air leakage position of the drilling hole. Therefore, optionally, in an embodiment of the present invention, determining the position of the air leakage channel according to the gas concentration at the sampling position includes: if the gas concentration from the target position in the sampling position to the bottom of the drilling hole increases, and the gas concentration from the hole mouth of the drilling hole to the target position decreases, then it is determined that the target position is the position of the air leakage channel.
[0034] Optionally, in an embodiment of the present invention, plugging the air leakage channel includes: arranging a guiding pipe in the gas extraction pipe of the drilling hole, wherein the enclosed cross-section between the first end of the guiding pipe close to the hole mouth of the drilling hole and the first end of the gas extraction pipe close to the hole mouth of the drilling hole is sealed; injecting a sealing liquid into the enclosed cavity between the gas extraction pipe and the guiding pipe; pressurizing the enclosed cavity through the guiding pipe to enable the sealing liquid to seal the air leakage channel. Specifically, after arranging the guiding pipe in the gas extraction pipe of the drilling hole, it further includes: arranging a sealing device at the first end of the gas extraction pipe close to the hole mouth of the drilling hole; plugging the enclosed cross-section between the first end of the guiding pipe close to the hole mouth of the drilling hole and the first end of the gas extraction pipe close to the hole mouth of the drilling hole. Injecting the sealing liquid into the enclosed cavity between the gas extraction pipe and the guiding pipe includes: injecting the sealing liquid into the enclosed cavity between the gas extraction pipe and the guiding pipe through the sealing device, wherein the second end of the guiding pipe extends deep into the coal seam position in the drilling hole.
[0035] In this embodiment, according to the detection and determination result of the air leakage channel, a guiding pipe with a small diameter can be arranged in the gas extraction pipe of the drilling hole, and a sealing device can be arranged at the first end pipe orifice of the gas extraction pipe close to the hole mouth of the drilling hole to plug the enclosed cross-section between the first end of the guiding pipe close to the hole mouth of the drilling hole and the first end of the gas extraction pipe close to the hole mouth of the drilling hole. The second end of the guiding pipe reaches the coal seam, and then the sealing liquid is injected into the enclosed cavity formed by the circular gap between the gas extraction pipe and the guiding pipe through the sealing device located at the hole mouth of the drilling hole. The sealing liquid flows into the cracks around the drilling hole through the ventilation holes of the gas extraction pipe such as the screen pipe from the enclosed cavity, and then pressurizes the inside of the drilling hole through the guiding pipe. The high-pressure gas injected from the first end of the guiding pipe generates pressure on the inside of the drilling hole through the second end of the guiding pipe, so that the sealing liquid penetrates into the cracks around the drilling hole to seal the air leakage channel.
[0036] Since the pressure difference and the flow channel are the preconditions for the flow of gas in the coal body, when the coal body is subjected to gas drainage and the gas is released, the coal body undergoes shrinkage deformation. During the shrinkage process, the expansion of the coal body fracture network will be caused, increasing the gas permeability of the coal body. At this time, the effect of too high gas drainage negative pressure on increasing the gas extraction volume is not very obvious. Although in a short period of time, the gas extraction volume shows an increasing trend with the increase of the gas drainage negative pressure, but as time goes by, its effect gradually weakens or disappears. At the same time, during the gas drainage process of the borehole, affected by the pipeline and the borehole sealing performance, too high gas drainage negative pressure will increase the air infiltration into the gas drainage pipeline, resulting in a decrease in the gas concentration of the extracted gas. The selection of the borehole gas drainage negative pressure should match the on-site coal seam conditions. Therefore, optionally, in an embodiment of the present invention, after step S14 determines whether there is a gas leakage channel and blocks the gas leakage channel according to the comparison result between the gas concentration at the orifice of the borehole and the third threshold, the method further includes: connecting the borehole to the gas drainage system; detecting the gas drainage parameters of the borehole, and the gas drainage parameters include at least one of the following: gas drainage flow rate and gas concentration; determining the gas drainage pressure of the borehole according to the gas drainage parameters. In this way, a reasonable gas drainage negative pressure can be optimized and determined according to the on-site measured gas drainage parameters and the actual geological conditions of the coal seam, so as to further improve the gas drainage efficiency of the mine coal seam.
[0037] In summary, as Figure 2 described above, when draining the coal seam gas on site, the gas concentration at the orifice of the borehole can be detected first. If the gas concentration at the orifice of the borehole is lower than the first threshold, then the gas concentration at the bottom of the borehole is detected. If the gas concentration at the bottom of the borehole is lower than the second threshold at this time, the gas flow channel must be dredged until the gas concentration at the bottom of the borehole is higher than the second threshold, and then the gas drainage pressure of the borehole is adjusted. If the gas concentration at the bottom of the borehole is still lower than the second threshold after dredging the gas flow channel, it indicates that the gas in the surrounding coal seam of this borehole has been fully desorbed after a long time of gas drainage, and this borehole can be blocked; after adjusting the gas drainage pressure of the borehole, if the detected gas concentration at the orifice of the borehole is still low at this time, for example, lower than the third threshold, the position of the gas leakage channel must be analyzed and judged, and the gas leakage channel is blocked until the gas concentration at the orifice of the borehole is higher than the third threshold, then this borehole can be connected to the gas drainage system for network gas drainage.
[0038] It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.
[0039] Each embodiment in this specification is described in a related manner. For the same or similar parts among the embodiments, reference can be made to each other, and the differences between each embodiment and other embodiments are emphasized.
[0040] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims
1. A method for increasing the gas drainage concentration of cross - seam boreholes, characterized in that, Including: If the gas concentration at the orifice of the drilled hole is lower than the first threshold value, detect the gas concentration at the bottom of the drilled hole; Determine whether the gas flow channel is blocked according to the comparison result between the gas concentration at the bottom of the drilled hole and the second threshold value, and dredge the gas flow channel; If the gas concentration at the bottom of the drilled hole is higher than the second threshold value, adjust the gas extraction pressure in the drilled hole, and detect the gas concentration at the orifice of the drilled hole; Determine whether there is a gas leakage channel according to the comparison result between the gas concentration at the orifice of the drilled hole and the third threshold value, and block the gas leakage channel.
2. The method for increasing the gas drainage concentration of cross-layer drilling holes according to claim 1, characterized in that, The determining whether the gas flow channel is blocked according to the comparison result between the gas concentration at the bottom of the drilled hole and the second threshold value, and dredging the gas flow channel includes: If the gas concentration at the bottom of the drilled hole is lower than the second threshold value, perform more than one pressure cycle on the drilled hole to dredge the gas flow channel; the pressure cycle is to inject compressed gas into the drilled hole, and after reaching the preset pressure and maintaining the pressure for the preset time, then relieve the pressure of the drilled hole at the preset speed; After dredging the gas flow channel, if the gas concentration at the bottom of the drilled hole is still lower than the second threshold value, block the drilled hole.
3. The method for increasing the gas drainage concentration of cross-layer boreholes according to claim 1, characterized in that, The determining whether there is a gas leakage channel and blocking the gas leakage channel includes: Under the first extraction pressure of the drilled hole, collect the gas at the sampling position of the drilled hole at the second extraction pressure, wherein the second extraction pressure is less than the first extraction pressure; Monitor the gas concentration at the sampled position collected; Determine the position of the gas leakage channel according to the gas concentration at the sampled position; Block the gas leakage channel.
4. The method for increasing the gas drainage concentration of cross-layer boreholes according to claim 3, characterized in that, The sampled position includes at least one of the following: the bottom of the drilled hole, the middle of the drilled hole, the orifice of the drilled hole, the combined position of the coal seam and the rock stratum in the drilled hole.
5. The method for increasing the gas drainage concentration of cross - seam boreholes according to claim 4, characterized in that, The determining the position of the gas leakage channel according to the gas concentration at the sampled position includes: If the gas concentration from the target position in the sampled position to the bottom of the drilled hole increases, and the gas concentration from the orifice of the drilled hole to the target position decreases, then determine that the target position is the position of the gas leakage channel.
6. The method for increasing the gas drainage concentration of cross - seam boreholes according to claim 5, characterized in that, The blocking the gas leakage channel includes: Arrange a guiding pipe in the extraction pipe of the drilled hole, wherein the enclosed cross-section between the first end of the guiding pipe close to the orifice of the drilled hole and the first end of the extraction pipe close to the orifice of the drilled hole is sealed; Inject a sealing liquid into the enclosed cavity between the extraction pipe and the guiding pipe; Pressurize the enclosed cavity through the guiding pipe so that the sealing liquid seals the gas leakage channel.
7. The method for increasing the gas drainage concentration of cross seam boreholes according to claim 6, characterized in that, After arranging the guiding pipe in the extraction pipe of the drilled hole, it further includes: Arrange a sealing device at the first end of the extraction pipe close to the orifice of the drilled hole; Block the enclosed cross-section between the first end of the guiding pipe close to the orifice of the drilled hole and the first end of the extraction pipe close to the orifice of the drilled hole.
8. The method for increasing the gas drainage concentration of cross-layer drilling holes according to claim 7, characterized in that The injecting the sealing liquid into the enclosed cavity between the extraction pipe and the guiding pipe includes: Inject sealing liquid into the enclosed cavity between the extraction pipe and the guiding pipe, wherein the second end of the guiding pipe extends deep into the coal seam position in the borehole.
9. The method for increasing the gas drainage concentration of cross-layer drilling holes according to claim 1, characterized in that, After determining whether there is a gas leakage channel and blocking the gas leakage channel according to the comparison result between the gas concentration at the orifice of the borehole and the third threshold, the method further includes: Connect the borehole to the extraction system; Detect the extraction parameters of the borehole, where the extraction parameters include at least one of the following: gas extraction flow rate and gas concentration; Determine the extraction pressure of the borehole according to the extraction parameters.