A secondary plugging system and method for improving gas extraction effect of a borehole

Abstract

The application discloses a kind of drilling secondary plugging system and method for improving gas extraction effect, belong to coal mine gas extraction technical field;The air tightness of each extraction drill hole in drilling field is detected and recorded by pressure gauge, and the determination data is determined using intelligent control system, to determine the invalid drill hole, carry out secondary plugging and hole sealing operation, using the way of "one drilling field one plugging" to control secondary hole sealing, effectively avoid the waste of resources caused by using "one size fits all" and the occurrence of extraction blank zone caused by too long hole sealing section;The application uses the liquid in the first bag to be pumped out by the drain pipe, and the sealing agent occupies the volume of the first bag with poor sealing effect caused by mining action, increases the secondary plugging space, and at the same time avoids the damage and destruction of the wall surface around the hole sealing section caused by the excessive pressure in the sealing space where the sealing agent is located, effectively ensures the quality of secondary hole sealing, and further improves the coal seam gas extraction effect.

Description

Technical Field

[0001] This invention belongs to the field of coal mine gas extraction technology, and relates to a secondary plugging system and method for boreholes to improve gas extraction efficiency. Background Technology

[0002] As my country's coal resources gradually move towards deeper mining, the inherent characteristics of coal seams—high temperature, high humidity, low temperature, and high permeability—increase the difficulty and effectiveness of gas extraction. The quality of borehole sealing is paramount for ensuring efficient coal seam gas extraction. However, during mining operations in the same or adjacent coal seams, disturbances can occur in the drilling boreholes, affecting their sealing and extraction efficiency. Even if good extraction results are achieved initially, the subsequent extraction effectiveness may be impacted by disturbances.

[0003] Meanwhile, due to the excavation of the roadway, the stress around the roadway roof is redistributed, which can be divided radially into a stress relief zone, a stress concentration zone, and a distant, unaffected original stress zone. During borehole sealing, the plastic zones within the stress relief and stress concentration zones are unsuitable for sealing due to numerous fractures; sealing operations in these areas are ineffective and detrimental to efficient coal seam gas extraction. However, the elastic zones and original stress zones within the stress concentration zones, which have not yet suffered damage, are suitable for sealing, effectively preventing air leakage during extraction. To reduce the impact of disturbance operations on borehole quality, increasing the sealing length is currently the primary method to reduce air leakage and improve extraction efficiency. However, increasing the sealing length has the following drawbacks: First, the "two-plug-one-injection" sealing method inevitably increases sealing costs; second, not all drainage boreholes in a drilling site will fail due to disturbance, and increasing the sealing length of all boreholes in a "one-size-fits-all" manner results in unnecessary waste; finally, excessively long sealing lengths can easily create "drainage blank zones," leading to substandard drainage in some areas and affecting subsequent safe coal mine production. Therefore, it is urgent to propose a new sealing method to solve the current predicament of partial borehole failure, high sealing costs, severe air leakage, and low extraction purity under disturbance conditions in drilling sites, thereby achieving efficient coal seam gas extraction and providing strong technical support for achieving the "dual carbon goals" of green, clean, and environmentally friendly production. Summary of the Invention

[0004] This invention overcomes the shortcomings of existing technologies and proposes a secondary sealing system and method for boreholes to improve gas extraction efficiency. It solves problems such as borehole sealing failure and low extraction purity caused by disturbance during coal seam gas extraction.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: A secondary sealing system for boreholes to improve gas extraction efficiency includes an injection pipe, an extraction pipeline, an intelligent control system, and a liquid distribution regulator. The injection pipe and extraction pipeline are arranged inside the borehole. A first bag and a second bag are arranged along the axial direction of the extraction pipeline from the inside to the outside of the borehole. A first pressure gauge and a second pressure gauge are installed on both sides of the second bag to measure the atmospheric pressure in the underground roadway and the pressure value of the sealed space in the secondary sealing section, P1 and P2, respectively. The first and second pressure gauges are connected to the intelligent control system and transmit the data to the intelligent control system in real time. The intelligent control system determines the location of the air leak based on the pressure measurement results and uses the liquid distribution regulator to connect the pump pipeline to the injection pipe of the extraction borehole where the air leak is located. The fully stirred sealing agent is then used to perform secondary sealing of the failed borehole.

[0006] Furthermore, it also includes a mixing and stirring device, which is connected to a liquid separator regulator.

[0007] Furthermore, the first bladder is connected to a drain pipe, and a safety valve is installed at the outlet of the drain pipe.

[0008] A leak-sealing method for a secondary leak-sealing system for boreholes to improve gas extraction efficiency includes the following steps: 1) Determine the location of the air leak based on the pressure measurement results inside each borehole, and connect the pump pipeline to the injection pipe of the extraction borehole where the air leak is located. 2) Calculate the volume of plugging agent required for sealing the failed borehole, and flow the required volume of plugging agent into the mixing and stirring device; after the plugging agent is fully stirred, pump the plugging agent into the sealed space inside the failed borehole through the pump pipeline, the liquid separator and the injection pipe. 3) Under the negative pressure provided by the air leakage channel and its own volume expansion, the sealing agent enters the air leakage channel and performs drilling and plugging. As the sealing agent is continuously pumped in, the fluid pressure in the sealed space also increases, which squeezes the first bag of the failed sealing section and causes the liquid in the first bag to flow out through the drain pipe. After the sealing agent in the sealed space solidifies, the second bag and the injection pipe are removed. Under the secondary sealing and plugging action, efficient extraction of coal seam gas is achieved.

[0009] Preferably, the drilling is carried out sequentially in the drilling site according to the layout plan, and the sealing section of the borehole is arranged between the elastic zone and the original stress zone in the stress concentration zone using the "two plugs and one injection" sealing method; the pressure inside the borehole is measured using a pressure gauge to check the integrity of the airtightness.

[0010] Preferably, the first and second pressure gauges on both sides of the second bag are used to measure the atmospheric pressure outside the borehole and the pressure inside the sealed space, respectively, to check the airtightness of the sealed space, and the measurement data are transmitted to the intelligent control system in real time; the intelligent control system determines the location of air leakage based on the pressure measurement results.

[0011] Preferably, when the number of leaking boreholes is 0, it indicates that none of the borehole sealing sections in the drilling site have failed, and there is no need to adjust the liquid distribution regulator; when the number of leaking boreholes is 1, it indicates that one borehole sealing section in the drilling site has failed, and it is necessary to adjust the liquid distribution regulator to connect the pump liquid pipeline to the injection pipe in the failed borehole. When the number of leaking boreholes is greater than 1, it indicates that multiple borehole sealing sections in the drilling site have failed. It is necessary to adjust the liquid distribution regulator in sequence to connect the pump liquid pipeline to the injection pipe in the failed borehole. At the same time, the principle of "heavy first, light last" should be adopted, first connecting the failed borehole with serious air leakage, and then sealing other failed boreholes in sequence.

[0012] Preferably, the drilling sealing section and the secondary plugging are both located between the elastic zone where the stress concentration zone has not yet been damaged and the original stress zone.

[0013] Even better, the depth of the secondary plugging hole exceeds the length of the fracture zone to prevent air in the roadway from entering the extraction pipeline through the fracture zone.

[0014] Preferably, the sealing agent comprises liquid A and liquid B, which undergo a chemical reaction after thorough mixing, gradually changing from liquid to solid, and their volume expands during solidification. When calculating the amount of sealing agent V, the expansion coefficient, the loss through the pipeline, and the volume of the leakage channel are considered; the calculation formula is as follows: In the formula, Vg represents the loss amount flowing through the pipeline, in cm. 3 Vm represents the volume of the sealed space for secondary sealing within the borehole sealing section, in cm³. 3 Vl represents the volume of the air leakage channel, in cm³. 3 ; i represents the i-th failed borehole in the extraction drilling site; A1 represents the expansion coefficient of the plugging agent volume; A2 represents the compensation coefficient.

[0015] The beneficial effects of this invention compared to the prior art are as follows: (1) The present invention adopts a secondary sealing method to carry out targeted sealing operations on the failed boreholes caused by mining. Compared with the traditional process of increasing the grouting length of the sealing section to improve the sealing performance of the borehole, it is more targeted and goal-oriented. At the same time, the intelligent control of the secondary sealing method of "one drilling site, one leak plugging" effectively avoids the waste of resources caused by the "one-size-fits-all" method and the occurrence of the extraction blank zone caused by the excessively long sealing section.

[0016] (2) The present invention uses a pressure gauge to detect and record the air tightness inside each extraction borehole in the drilling site, and uses an intelligent control system to judge and analyze the measured data in real time, so as to identify the failed borehole and carry out secondary sealing operations, which greatly improves the quality and effect of secondary sealing of the borehole.

[0017] (3) The present invention uses a drain pipe to extract the liquid in the first bag. The sealing agent occupies the volume of the first bag, which has a poor sealing effect due to the action of the extraction, thereby increasing the space for secondary plugging. At the same time, it avoids damage to the wall surface around the sealing section due to excessive pressure in the sealed space where the sealing agent is located, effectively ensuring the quality of secondary sealing and thus improving the coal seam gas extraction effect. Attached Figure Description

[0018] Figure 1 This is a schematic flowchart of the secondary sealing method for borehole drilling in an embodiment. Figure 2 This is a schematic diagram of the overall structure of the secondary plugging device for drilling sites, as shown in the embodiment. Figure 3 This is a schematic diagram of the structure before the second bladder inside the borehole is opened. Figure 4 This is a schematic diagram of the structure after the second bladder inside the borehole is expanded. Figure 5 This is a schematic diagram of the structure at the secondary plugging and sealing point inside the borehole; Figure 6 A schematic diagram of a secondary fluid injection system for plugging leaks in boreholes; Figure 7 A schematic diagram showing the gas / air migration direction after secondary fluid injection for plugging in boreholes; Figure 8 A schematic diagram of the stress on the first bladder after secondary fluid injection for plugging in boreholes; Figure 9 A schematic diagram of the structure after the secondary fluid injection and plugging work in the borehole is completed; Figure 10 This is a schematic diagram of the structure of the second sac; In the diagram: 1. Fracturing zone; 2. Injection pipe; 3. Sealing section; 4. Extraction pipeline; 5. First bag; 6. First pressure gauge; 7. Second bag; 8. Injection pipe connector; 9. Second pressure gauge; 10. Drain pipe; 11. Sealing agent; 12. Intelligent control system; 13. Mixing and stirring device; 14. Liquid separator; 15. Drill hole. Detailed Implementation

[0019] To make the technical problems to be solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. The technical solutions of this invention are described in detail below with reference to the embodiments and accompanying drawings, but the scope of protection is not limited thereto.

[0020] See Figure 1-10 This embodiment proposes a system for improving gas extraction efficiency through secondary plugging of boreholes, including an injection pipe 2, an extraction pipeline 4, a bag, a pressure gauge, an intelligent control system 12, a liquid separator 14, and a mixing and stirring device 13. The injection pipe 2 is connected to the injection pipe connector 8; on the outer wall of the extraction pipeline 4, two first bags 5 and one second bag 7 are arranged along the axial direction of the extraction pipeline 4 from the inside to the outside of the borehole 15. A first pressure gauge 6 is installed on one side of the second bag 7 and a second pressure gauge 9 is installed on the other side. They are used to measure the atmospheric pressure in the underground roadway and the pressure values ​​of the sealed space in the secondary sealing section, P1 and P2, respectively, and transmit the data to the intelligent control system 12 in real time; the intelligent control system 12 determines the location of the air leak based on the pressure measurement results, and uses the liquid distribution regulator 14 to connect the pumping pipeline to the injection pipe 2 of the extraction borehole where the air leak is located; the fully stirred sealing agent 11 is used to perform secondary sealing and plugging of the failed borehole 15, effectively preventing air in the roadway from entering the borehole 15, improving the purity of gas extraction, and realizing efficient extraction of coal seam gas.

[0021] The first pouch 5 is connected to the drain pipe 10, and a safety valve is installed at the outlet of the drain pipe 10. Furthermore, the intelligent control system 12 is a conventional computer control system; the intelligent control system 12 is an existing device and program, and will not be described in detail here.

[0022] See Figure 1-10 This embodiment proposes a method for improving gas extraction efficiency through secondary borehole plugging, comprising the following three steps: S1. The "two-plug-one-injection" sealing operation is carried out on borehole 15 and its airtightness is checked: Boreholes are drilled sequentially in the drilling site according to the layout plan of the extraction borehole 15. The sealing section of borehole 15 is arranged between the elastic zone and the original stress zone in the stress concentration zone using the "two-plug-one-injection" sealing method. The pressure inside the borehole is measured using a pressure gauge to check the integrity of its airtightness. S2. Determine the location of the air leak and intelligently adjust the plugging pipeline: Due to the action of mining, some boreholes 15 fail and air leaks occur; the intelligent control system 12 determines the location of the air leak based on the pressure measurement results and uses the liquid separator 14 to connect the pumping pipeline to the injection pipe 2 of the extraction borehole where the air leak is located. S3. Effectively seal gas leakage channels and achieve efficient gas extraction: The sealing agent 11 is used to seal the failed borehole 15 for a second time, which effectively prevents air in the roadway from entering the borehole 15, improves the purity of gas extraction, and achieves efficient extraction of coal seam gas.

[0023] The "two-plugging-one-injection" sealing operation performed in step S1, and the airtightness check, includes the following steps: S11. The sealing sections 3 of borehole 15 are arranged between the elastic zone and the original stress zone in the stress concentration zone. The "two-plug and one-injection" method is used to effectively seal the borehole 15. After the sealing sections 3 solidify, the coal seam gas extraction operation is carried out. S12. The injection tube 2 and the second bag 7 are transported to the predetermined sealing position, and liquid is injected into the second bag 7 to expand its volume and form a sealed space with the sealing section 3. S13. The first pressure gauge 6 and the second pressure gauge 9 on both sides of the second bag 7 are used to measure the atmospheric pressure outside the borehole 15 and the pressure inside the sealed space, respectively, to check the airtightness of the sealed space, and the measurement data are transmitted to the intelligent control system 12 in real time.

[0024] The process of determining the air leak location and intelligently adjusting the leak-sealing pipeline in step S2 includes the following steps: S21. In the extraction drilling site, cracks are generated around the sealing section 3 inside the drilling hole 15 subjected to mining action, causing the sealing to fail and resulting in air leakage. S22, The intelligent control system 12 judges and determines the location of the air leak based on the pressure measurement results inside each borehole 15, and controls the liquid distribution regulator 14 to connect the pumping pipeline to the injection pipe 2 of the extraction borehole 15 where the air leak is located. S23. When the number of leaking boreholes is 0, it indicates that none of the borehole sealing sections 3 in the drilling site have failed, and there is no need to adjust the liquid distribution regulator 14. When the number of leaking boreholes is 1, it indicates that one sealing section 3 in the drilling site has failed, and the liquid distribution regulator 14 needs to be adjusted to connect the pumping pipeline to the injection pipe 2 in the failed borehole. When the number of leaking boreholes is greater than 1, it indicates that multiple sealing sections 3 in the drilling site have failed, and the liquid distribution regulator 14 needs to be adjusted sequentially to connect the pumping pipeline to the injection pipe 2 in the failed borehole. At the same time, the principle of "heavy first, light last" should be adopted, first connecting the severely leaking failed borehole 15, and then sealing other failed boreholes 15 in sequence.

[0025] The effective sealing of gas leakage channels in step S3 to achieve efficient gas extraction includes the following steps: S31, The intelligent control system 12 calculates the volume of the sealing agent 11 required to seal the failed borehole 15, and the volume of the sealing agent 11 is fed into the mixing and stirring device 13 below it; S32. After the sealing agent 11 is fully stirred, it is pumped into the sealed space inside the failed borehole 15 through the pump pipeline, the liquid distribution regulator 14 and the injection pipe 2. S33, the sealing agent 11 enters the air leakage channel under the negative pressure provided by the air leakage channel and its own volume expansion, and effectively seals the leak by drilling 15; S34. As the sealing agent 11 is continuously pumped in, the fluid pressure in the sealed space also increases. When the pressure is too high, it will squeeze the first bag 5 of the failed sealing section 3 and make the liquid in the first bag 5 flow out through the drain pipe 10, thereby avoiding the excessive pressure in the sealed space from causing damage to the surrounding hole wall and ensuring the sealing effect of the secondary sealing. S35. After the sealing agent 11 in the confined space solidifies, the second bag 7 and the injection pipe 2 are removed; under the good sealing effect of the secondary sealing, efficient extraction of coal seam gas is achieved.

[0026] The sealing agent 11 comprises liquid A and liquid B, which undergo a chemical reaction after thorough mixing, gradually transforming from a liquid to a solid, and expanding in volume during solidification. When calculating the dosage (V) of the sealing agent 11, the expansion coefficient, the loss through the pipeline, and the volume of the leakage channel need to be considered. The calculation formula is as follows: In the formula, Vg represents the loss amount flowing through the pipeline, in cm. 3 Vm represents the volume of the sealed space within the secondary sealing section 3, in cm³. 3 Vl represents the volume of the air leakage channel, in cm³. 3 ; i represents the i-th failed borehole in the extraction drilling site; A1 represents the expansion coefficient of the sealing agent 11; A2 represents the compensation coefficient.

[0027] The intelligent control system 12 determines the location of the air leak by judging and analyzing the pressure measurement results inside each borehole 15, and controls the liquid distribution regulator 14 to connect the pumping pipeline to the injection pipe 2 of the extraction borehole where the air leak is located; at the same time, based on the calculated amount of sealing agent 11, it controls the amount of sealing agent 11 used and the start-up and pumping operation of the mixing and stirring device 13; the flow rate of sealing agent 11 in the pumping pipeline can be recorded in real time and transmitted to the intelligent control system 12.

[0028] The first bladder 5 is connected to the drain pipe 10, and a safety valve is installed at the outlet of the drain pipe 10. When the pressure inside the first bladder 5 exceeds the safety threshold, the safety valve opens to discharge the excess fluid from the first bladder 5. As the sealing agent 11 is continuously pumped in and expands on its own, the fluid pressure in the sealed space of the secondary sealing gradually increases. When the pressure is too high, it squeezes the first bladder 5 and forces the liquid inside the first bladder 5 to flow out through the drain pipe 10, thereby preventing excessive pressure in the sealed space from damaging the surrounding hole walls and ensuring the sealing effect of the secondary sealing.

[0029] The first pressure gauge 6 and the second pressure gauge 9 on both sides of the second airbag 7 monitor and record the atmospheric pressure in the underground roadway and the pressure in the sealed space in the secondary sealing section 3. When the mining action creates a through-crack around the sealing section 3, the borehole 15 fails and the sealing effect is not good, so secondary sealing operation needs to be carried out.

[0030] One side of the liquid separator 14 is connected to the injection pipe 2 in each extraction borehole 15, and the other side is connected to the pump pipeline. After the failed borehole is identified, the intelligent control system 12 controls the liquid separator 14 to connect to the injection pipe 2 of the extraction borehole where the air leak is located in sequence.

[0031] The criteria and principles for the intelligent control system 12 to control the liquid distribution regulator 14 and the injection pipe 2 of the failed borehole 15 are as follows: When the number of leaking boreholes is 0, it indicates that none of the borehole sealing sections in the drilling site have failed, and there is no need to adjust the liquid distribution regulator 14. When the number of leaking boreholes is 1, it indicates that one borehole sealing section in the drilling site has failed, and the liquid distribution regulator 14 needs to be adjusted to connect the pumping pipeline to the injection pipe 2 in the failed borehole. When the number of leaking boreholes is greater than 1, it indicates that multiple borehole sealing sections in the drilling site have failed, and the liquid distribution regulator 14 needs to be adjusted sequentially to connect the pumping pipeline to the injection pipe 2 in the failed borehole. At the same time, the principle of "heavy first, light last" should be adopted, first connecting the severely leaking failed borehole, and then sealing other failed boreholes in sequence.

[0032] Under the effects of its own expansion and the negative pressure of the air leakage channel, the sealing agent 11 can better enter the through-cracks around the sealing section 3 and achieve a good sealing effect. At the same time, the volume of the first bag 5, which is subjected to compression, decreases, and the sealing agent 11 occupies the original volume of the sealing section 3, effectively sealing the mining cracks around the borehole wall of the sealing section 3.

[0033] The borehole sealing section 3 and the secondary plugging are both located between the elastic zone and the original stress zone where the stress concentration zone has not yet been damaged, which can effectively prevent air leakage during the extraction process; the depth of the secondary plugging exceeds the length of the fracture zone 1 to prevent air in the roadway from entering the extraction pipeline 4 through the cracks in the fracture zone 1.

[0034] The above description is a further detailed explanation of the present invention in conjunction with specific preferred embodiments. It should not be considered that the specific embodiments of the present invention are limited to this. For those skilled in the art, several simple deductions or substitutions can be made without departing from the present invention, and all of these should be considered to fall within the scope of patent protection determined by the submitted claims.

Claims

1. A secondary plugging system for boreholes to improve gas extraction efficiency, characterized in that, The system includes an injection pipe (2), an extraction pipeline (4), an intelligent control system (12), a mixing and stirring device (13), a liquid separator (14), a first bag (5), and a second bag (7). The injection pipe (2) and the extraction pipeline (4) are arranged inside the borehole (15). The first bag (5) and the second bag (7) are arranged sequentially from the inside to the outside of the borehole (15) along the axial direction of the extraction pipeline (4). After the second bag (7) is opened, it forms a sealed space with the sealing section (3) for secondary sealing and plugging. A first pressure gauge (6) and a second pressure gauge (9) are installed on both sides of the second bag (7). The first pressure gauge (6) is used to measure the pressure of the well. The atmospheric pressure in the lower tunnel is P1, and the second pressure gauge (9) is used to measure the pressure P2 in the sealed space; both the first pressure gauge (6) and the second pressure gauge (9) are connected to the intelligent control system (12) and transmit the measured data to the intelligent control system (12) in real time; the mixing and stirring device (13) is connected to the liquid separator (14) through the pump pipeline, and the liquid separator (14) is connected to the injection pipe (2) of each borehole (15) in the drilling site; the intelligent control system (12) is used to determine the failed borehole with air leakage based on the pressure measurement results of each borehole (15), and control the liquid separator (14) to connect the pump pipeline to the failed borehole. The injection pipe (2) inside the hole is selectively connected; the mixing and stirring device (13) is used to fully mix liquid A and liquid B to form a sealing agent (11), and to transport the sealing agent (11) through the pump pipeline, the liquid separator (14) and the injection pipe (2) to the sealed space of the failed borehole; after the liquid A and liquid B are mixed, a chemical reaction occurs, causing the sealing agent (11) to gradually solidify from liquid to solid, and to expand in volume during the solidification process; the first bag (5) is connected to a drain pipe (10), and a safety valve is installed at the outlet of the drain pipe (10); after the sealing agent (11) is pumped into the sealed space, under the negative pressure of the air leakage channel and the sealing agent (11) Under the effect of volume expansion, it enters the air leakage channel; as the sealing agent (11) is continuously pumped in and expands in volume, the pressure in the sealed space increases and exerts a squeezing effect on the first bag (5). When the pressure in the first bag (5) exceeds the opening threshold of the safety valve, the safety valve opens, allowing the liquid in the first bag (5) to be discharged through the drain pipe (10). The volume of the first bag (5) decreases accordingly, and the sealing agent (11) occupies the space released after the volume of the first bag (5) decreases and seals the air leakage channel. The liquid drainage and volume reduction of the first bag (5) is used to buffer the continued increase of pressure in the sealed space, so as to reduce the risk of further damage to the borehole wall.

2. A leak-sealing method for a secondary leak-sealing system for improving gas extraction efficiency in boreholes, as described in claim 1, characterized in that... Includes the following steps: 1) Transport the injection pipe (2) and the second bag (7) to the predetermined secondary sealing position, inject liquid into the second bag (7) to open the second bag (7) and form a sealed space for secondary sealing and plugging between the second bag (7) and the sealing section (3); use the first pressure gauge (6) to measure the atmospheric pressure P1 in the underground roadway, use the second pressure gauge (9) to measure the pressure P2 in the sealed space, and transmit P1 and P2 to the intelligent control system (12) in real time. 2) The intelligent control system (12) determines the failed boreholes that have leaked air based on the pressure measurement results of each borehole (15) in the drilling site, and controls the liquid distribution regulator (14) to selectively connect the pumping pipeline to the injection pipe (2) in the failed borehole. 3) When it is determined that there are n failed boreholes in the drilling site, calculate the total amount V of the sealing agent (11) required for secondary plugging of the n failed boreholes; transport liquid A and liquid B used to form the sealing agent (11) to a mixing and stirring device (13) for thorough mixing, so that liquid A and liquid B react chemically to form a sealing agent (11) that gradually solidifies from liquid to solid and expands in volume during the solidification process; wherein, the total amount V of the sealing agent (11) is calculated according to the following formula: ; In the formula, V g This indicates the loss amount flowing through the pipeline, in cm. 3 ; V m This indicates the volume of the sealed space within the secondary sealing section (3), expressed in cm. 3 V l Indicates the volume of the air leakage channel, in cm. 3 ; i Indicates the first in the extraction drilling site i One failed borehole; n This indicates the number of failed boreholes within the drilling site; A 1 represents the coefficient of volume expansion of the sealing agent (11); A 2 represents the compensation coefficient; V This indicates the amount of sealant required for secondary leak sealing, in cm. 3 ; 4) Based on the selective connection result of the liquid separator (14), the fully mixed sealing agent (11) is pumped into the sealed space of each failed borehole through the pumping pipeline, the liquid separator (14) and the injection pipe (2), so that the sealing agent (11) enters the air leakage channel under the action of the extraction negative pressure in the air leakage channel and the volume expansion of the sealing agent (11); 5) For each failed borehole connected to the pump fluid line, as the sealing agent (11) is continuously pumped in and expands in volume, the pressure in the sealed space increases and squeezes the first bag (5); when the external pressure causes the pressure in the first bag (5) to exceed the opening threshold of the safety valve, the safety valve opens, and the liquid in the first bag (5) is discharged through the drain pipe (10), which reduces the volume of the first bag (5) and releases the space occupied by the sealing agent (11); the sealing agent (11) occupies the space and seals the air leakage channel, thereby buffering the continued increase in pressure in the sealed space; 6) After the sealing agent (11) in the corresponding sealed space solidifies, remove the second bag (7) and injection pipe (2) from the failed borehole to complete the secondary sealing and plugging of the failed borehole.

3. The leak-sealing method according to claim 2, characterized in that, The borehole (15) is constructed sequentially in the drilling site according to the borehole layout plan, and the initial sealing is carried out by the "two plugs and one injection" sealing method. After the initial sealing is completed, the pressure inside the borehole (15) is measured by a pressure gauge to check the airtightness of the initial sealing.

4. The leak-sealing method according to claim 2, characterized in that, When the number of leaking boreholes determined by the intelligent control system (12) is 0, the liquid distribution regulator (14) is not controlled; when the number of leaking boreholes is 1, the liquid distribution regulator (14) is controlled to connect the pump liquid pipeline to the injection pipe (2) in the failed borehole; when the number of leaking boreholes is greater than 1, the liquid distribution regulator (14) is controlled to connect the pump liquid pipeline to the injection pipe (2) in each failed borehole in sequence, and according to the principle of heavy first and light last, the failed borehole with serious air leakage is connected first, and then other failed boreholes are connected in sequence.

5. The leak-sealing method according to claim 2, characterized in that, The sealing section (3) and the secondary plugging location are both located between the elastic zone and the original stress zone within the stress concentration zone, where no damage has yet occurred.

6. The leak-sealing method according to claim 5, characterized in that, The sealing depth of the secondary plug exceeds the length of the fracture zone (1) to prevent air in the roadway from entering the extraction pipeline (4) through the cracks in the fracture zone (1).

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