Device and method for fixed-point multiple-sealed gas extraction drilling

Abstract

The present invention provides a device and method for sealing a gas extraction borehole at a fixed point multiple times, and relates to the field of gas extraction technology. The device includes a casing, a bladder, a push-pull telescopic rod, a pressure gauge, a special-shaped spring, a borehole detector, a grouting valve, an air compressor, and a controller. The casing and the bladder cooperate with each other and are arranged in the borehole, and their positions are moved by pushing and pulling the telescopic rod. The special-shaped spring is fixed in the casing to adjust the positions of the casing and the bladder; the air compressor is connected to the grouting pipeline, and a grouting valve is provided on the grouting pipeline. The pressure gauge monitors the air pressure in the device, and the borehole detector is inserted into the borehole through the casing to monitor the crushing state of the coal body. The controller controls the borehole detector and the grouting tank to grout and fill the gap. The device can be used to achieve fixed-point movement of the sealing position, and enhance the sealing performance of the coal seam fissure area. The method also has the advantages of being durable and recyclable, extending the sealing time and service life of the borehole, and improving the gas extraction efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of gas extraction, and in particular to a device and method for sealing a gas extraction borehole multiple times at a fixed point. Background Art

[0002] Coal resources account for a significant portion of energy consumption, and the safe production of coal resources is receiving increasing attention. Gas prevention and control can help address the problem of mine gas disasters. Currently, the current approach to gas prevention and control is to extract gas before mining. The low gas extraction rate is primarily due to inadequate borehole sealing, in addition to uncontrollable geological factors. Due to the redistribution of coal rock stress and the shrinkage and creep of the coal matrix, cracks around the borehole expand, creating new fissure channels. Traditional single-shot sealing methods can result in air leakage, resulting in a decrease in gas extraction concentration and efficiency.

[0003] Leakage cracks in the borehole area allow air to enter through these cracks, severely impacting gas extraction effectiveness. Due to the complex structure of the coal seam, blindly transporting raw materials into a larger space prevents them from reaching the designated sealing location, failing to achieve the designed sealing length, and making it difficult to control the sealing time. This results in suboptimal sealing results and a low sealing success rate, impacting gas extraction effectiveness.

[0004] To solve the above problems, it is necessary to implement multiple sealing operations to extend the gas extraction effect and the service life of the borehole. For this purpose, a gas extraction borehole sealing method is needed to achieve fixed-point and timed sealing and improve the sealing success rate to meet the requirements of gas extraction borehole sealing in coal mines. Summary of the Invention

[0005] In order to accurately locate the position of coal seam fractures and perform multiple sealing when the gas extraction borehole is insufficiently sealed and the sealing position is inaccurate, thereby achieving long-term sealing of the borehole, extending the gas extraction efficiency and the life cycle of the borehole, the present invention provides a device and method for multiple sealing of gas extraction boreholes at fixed points, and the specific technical solution is as follows.

[0006] A device for sealing a gas extraction borehole multiple times at a fixed point comprises a casing, a bladder, a push-pull telescopic rod, a pressure gauge, a special-shaped spring, a borehole detector, a grouting valve, an air compressor and a controller. The casing and the bladder cooperate with each other and are arranged in the borehole, and their positions are moved by pushing and pulling the telescopic rod; the special-shaped spring is fixed in the casing to adjust the positions of the casing and the bladder; the air compressor is connected to a grouting pipeline, and a grouting valve is provided on the grouting pipeline; the pressure gauge monitors the air pressure of the air bag; the borehole detector extends into the borehole through the casing to monitor the crushing state of the coal body; and the controller controls the operation of the borehole detector and the grouting tank and controls the grouting to fill the gaps.

[0007] Preferably, the sleeve includes a first sleeve and a second sleeve, and the pouch includes a first pouch and a second pouch; the first sleeve and the second sleeve are respectively arranged at both ends of the push-pull telescopic rod, the first pouch is sleeved on the first sleeve, and the second pouch is sleeved on the second sleeve.

[0008] Preferably, a first grouting valve is provided at the connection between the first bladder bag and the grouting pipe, and a second grouting valve is provided at the connection between the injection pipeline and the second grouting bag.

[0009] Preferably, the air compression device includes an automatic air compression tank, a rotary valve and an air compression pipeline. The automatic air compression tank and the air compression pipeline are connected. The rotary valve is arranged at the air outlet of the automatic air compression tank. The air compression pipeline, grouting pipeline and pressure gauge are connected to a three-way valve.

[0010] It is also preferred that the drilling detector includes a camera, a pulley, a spring, a probe and a detection tube. A camera is provided at the front end of the detection tube. A slurry injection hole is also provided on the detection tube. The spring is provided between the mounting rod of the pulley and the detection tube. The probe is connected and fixed through a wooden board on the detection tube.

[0011] It is also preferred that the first casing and the second casing are sleeved on the gas extraction pipe; and the detection pipe of the borehole detector is telescoped along the outer wall of the gas extraction pipe.

[0012] A method for drilling a fixed-point, multiple-time sealed gas extraction hole using the above-mentioned device for drilling a fixed-point, multiple-time sealed gas extraction hole comprises the following steps:

[0013] S1. Drilling a hole in the coal seam and inserting a casing and a bladder into the hole;

[0014] S2. Insert the gas extraction pipe into the borehole;

[0015] S3. Inject gas into the first bag through the grouting line and the first grouting valve. After increasing the injection pressure, the gas fills the first bag. After the injection is complete, close the three-way valve.

[0016] S4. The controller controls the borehole detector to advance into the borehole, and the camera of the borehole detector detects the borehole wall to determine the coal fracture area;

[0017] S5. Press the shaped spring, which pushes the second cannula and the second bag to the set position;

[0018] S6. Inject liquid into the second bag through the injection line. After the second bag is filled with liquid, the plugging slurry is filled under pressure;

[0019] S7. Continue to control the drilling detector to slide back and forth to determine the coal seam cracks between the first bag and the second bag, and fill the gaps through the slurry injection holes on the detection tube;

[0020] S8. After the slurry solidifies, gas extraction operations are carried out. After the extraction is completed, the bag and casing are removed and recovered.

[0021] It is further preferred that the first casing is arranged at a distance of 0.5 m from the borehole opening.

[0022] It is further preferred that during the gas extraction operation, when the gas extraction concentration is lower than 0.5%, extraction is stopped.

[0023] The present invention provides a device and method for sealing a gas extraction borehole multiple times at a fixed point, which has the following beneficial effects:

[0024] (1) The device solves the sealing defects of existing large-diameter and long-distance gas extraction boreholes in deep coal seams, increases the concentration of extracted gas, has a significant effect, realizes fixed-point sealing, improves the success rate of sealing, and meets the needs of coal mine on-site gas control and other work.

[0025] (2) At the end of the gas extraction work, this method can realize the recycling of the extraction pipe, special-shaped spring, and drilling detector, reduce the consumption rate and extraction cost of the extraction device, and improve the extraction working environment.

[0026] (3) This method achieves multiple sealing of gas extraction boreholes. The borehole detector not only plays the role of detecting the sealing position, but also achieves three sealing, which reduces costs, enhances sealing, and improves the extraction rate.

[0027] (4) The device and method can improve the sealing of gas extraction boreholes, extend the gas extraction effect and the service life of the device, effectively improve the gas extraction efficiency, and have wide practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the layout of fixed-point multiple sealed gas extraction boreholes;

[0029] Figure 2 is a schematic cross-sectional view of the installation of the first bladder;

[0030] Figure 3 is a schematic cross-sectional view of the installation of the second bladder;

[0031] Figure 4 It is a structural diagram of a borehole detector;

[0032] In the figure: 1-coal seam; 21-first bladder bag; 22-second bladder bag; 31-first grouting valve; 32-second grouting valve; 4-gas extraction pipe; 5-push-pull telescopic rod; 6-first casing; 7-second casing; 8-liquid injection pipe; 9-drilling detector; 91-pulley; 92-wooden board; 93-probe; 94-spring; 95-camera; 96-slurry injection hole; 10-detector camera; 11-grouting pipeline; 12-special-shaped spring; 13-three-way valve; 14-pressure gauge; 15-automatic air pressure tank; 16-rotary valve; 17-controller; 18-liquid injection tank; 19-grouting tank; 20-drilling hole. DETAILED DESCRIPTION

[0033] Combine Figures 1 to 4 As shown, the specific implementation of the device and method for fixed-point multiple sealing gas extraction drilling provided by the present invention is described.

[0034] A device for sealing a gas extraction borehole at a fixed point multiple times includes a casing, a bladder, a push-pull telescopic rod, a pressure gauge, a special-shaped spring, a borehole detector, a grouting valve, an air compressor, and a controller. The device's driving structure primarily moves the casing and bladder at a fixed point, and the borehole is sealed primarily in the coal seam fissure area, enhancing its sealing and increasing the extraction rate. The grouting structure primarily complements the sealing system, injecting gas, liquid, and solid through the grouting pipe to achieve the purpose of sealing. The device is recycled primarily through the special-shaped spring, borehole detector, and extraction pipe, extending the device's service life and saving costs. The casing and bladder cooperate with each other and are arranged in the borehole 20. They are moved by pushing and pulling the telescopic rod 5 to achieve precise positioning within the borehole 20. The special-shaped spring 12 is fixed in the casing to adjust the position of the casing and the bladder. The special-shaped spring is specifically umbrella-shaped, which is convenient for applying elastic force and recovering from the borehole. The left end of the spring is fixed to the inner wall of the first casing 6, and the right end is connected to the second casing 7. A pressure value of the spring is set as needed to push the second casing 7 to separate from the first casing 6 to the required position. The air compressor is connected to the grouting pipeline 11, and a grouting valve is provided on the grouting pipeline 11. The air compressor can adjust the pressure of the gas injection and realize linear pressurization, and then cooperate with the grouting valve to realize gas injection sealing. The pressure gauge 14 monitors the air pressure of the airbag, and the borehole detector 9 is inserted into the borehole through the casing to monitor the crushing state of the coal body. The controller 17 controls the operation of the borehole detector 9 and the grouting tank 18 and controls the grouting to fill the gap.

[0035] The casing includes a first casing 6 and a second casing 7. The casing is fixed at one end and fixed to the push-pull telescopic rod 5 at the other end, which facilitates the fixed-point movement and sealing of the gas extraction borehole. The bag includes a first bag 21 and a second bag 22. Gas is injected into the bag, which expands until it combines with the surface of the borehole to form a sealed section of the gas extraction borehole. The first casing 6 and the second casing 7 are respectively arranged at the two ends of the push-pull telescopic rod 5. The first bag 21 is sleeved on the first casing 6, and the second bag 22 is sleeved on the second casing 7. A first grouting valve is provided at the connection between the first bag 21 and the grouting pipeline, and a second grouting valve is provided at the connection between the injection pipeline and the second grouting bag.

[0036] The compressed air device includes an automatic compressed air tank 15, a rotary valve 16, and a compressed air pipeline. The automatic compressed air tank 15 is connected to the compressed air pipeline. The rotary valve 16 is set at the air outlet of the automatic compressed air tank 15. The compressed air pipeline, grouting pipeline, and pressure gauge are connected to the three-way valve 13. The three-way valve 13 is made of stainless steel and can be sealed with the gas pipeline. The pressure gauge 14 is a pointer-type high-precision pressure gauge with a range of 0-10MPa and a measurement accuracy of 0.05MPa. The air compression device selects nitrogen as the gas injection material, and the nitrogen is injected into the first bag 21 through the grouting pipe through the first grouting valve 31, and the grouting pressure is gradually increased to exceed the opening pressure A of the bag grouting valve, so that the grouting valve connected to the first bag is opened. As the grouting pressure continues to increase, the gas gradually fills the first bag 21 and penetrates into the cracks on the inner wall of the borehole in this area; then the liquid injection is continued, and the second bag 22 is injected through the second grouting valve 32 of the grouting pipe, and the grouting pressure is gradually increased to exceed the opening pressure B of the second bag grouting valve, so that the grouting valve of the second bag 22 is opened. Under the action of the liquid injection pressure, the liquid gradually fills the second bag 22 and penetrates into the cracks on the inner wall of the borehole 20 in this area.

[0037] The borehole detector 9 includes a camera 95, a pulley 91, a spring 94, a probe 93, and a detection tube. The camera 95 is located at the front of the detection tube, which is also provided with a slurry injection hole. The spring 94 is positioned between the mounting link of the pulley 91 and the detection tube. The probe 93 is connected and fixed via a wooden board on the detection tube. The borehole detector 9 is primarily used to locate the location of the secondary grouting seal, detect coal wall fissures, and accurately locate the specific location of the secondary seal. Once the secondary seal is complete, the coal wall fissures and debris areas are detected again, and slurry is injected into the gap between the two sealed sections through the slurry injection hole to improve the seal.

[0038] The first casing 6 and the second casing 7 are mounted on the gas extraction pipe. The detection tube of the borehole detector 9 is extended and retracted along the outer wall of the gas extraction pipe. The borehole detector is slid back and forth under the control of the controller 17 to continue searching for the coal seam cracks between the two bags. The grouting controlled by the computer pressure control meter causes the slurry to flow to the slurry flow hole of the probe to fill the cracks and achieve three-time sealing.

[0039] This device solves the sealing defects of existing large-diameter and long-distance gas extraction boreholes in deep coal seams. The extracted gas concentration is increased with significant effect, fixed-point sealing is achieved, and the success rate of sealing is improved, meeting the needs of coal mine on-site area gas control and other work.

[0040] A method for drilling a fixed-point, multiple-time sealed gas extraction hole using the above-mentioned device for drilling a fixed-point, multiple-time sealed gas extraction hole comprises the following steps:

[0041] S1. Drill a hole in the coal seam and insert a casing and a bladder into the hole; the first casing is set at 0.5m from the hole opening.

[0042] S2. Insert the gas extraction tube into the borehole; at the same time, put the first airbag and the second airbag on the first casing and the second casing respectively, put the second casing on the push-pull telescopic rod, and put them together into the first casing, and also insert the gas extraction tube into the borehole.

[0043] S3. Inject gas into the first bag through the grouting pipeline and the first grouting valve. After increasing the injection pressure, the gas fills the first bag. After the injection is completed, close the three-way valve. After the injection is completed, close the three-way valve to block the connection between the grouting pipe and other pipelines.

[0044] S4. The controller controls the borehole detector to advance into the borehole, and the camera of the borehole detector detects the borehole wall to determine the coal body fracture area.

[0045] S5. Press the special-shaped spring, which pushes the second sleeve and the second bag to the set position.

[0046] S6. Inject liquid into the second bag through the liquid injection pipeline. After the second bag is filled with liquid, the sealing slurry is filled under pressure.

[0047] S7. Continue to control the drilling detector to slide back and forth to determine the coal seam cracks between the first bag and the second bag, and fill the gaps through the slurry injection holes on the detection tube.

[0048] S8. After the slurry solidifies, gas extraction operations are carried out. After the extraction is completed, the bag and casing are removed and recovered.

[0049] During gas extraction operations, extraction is stopped when the gas concentration falls below 0.5%. At the end of the gas extraction process, the extraction tube, special-shaped spring, and borehole detector are recycled, reducing the consumption rate of the extraction equipment and extraction costs, while improving the extraction working environment.

[0050] This device can achieve multiple, targeted sealing of gas extraction boreholes, allowing for device recycling and long-term sealing of the borehole, extending gas extraction efficiency and the borehole's lifespan. This method effectively addresses issues such as gas leakage, inaccurate positioning, and complex operation in gas extraction boreholes. This device and method improve the sealing of gas extraction boreholes, extend gas extraction effectiveness, and extend the device's lifespan, effectively enhancing gas extraction efficiency and possessing broad practical applications.

[0051] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A device for sealing a gas extraction borehole multiple times at a fixed point, characterized in that: The device comprises a casing, a bladder, a push-pull telescopic rod, a pressure gauge, a special-shaped spring, a borehole detector, a grouting valve, an air compressor, and a controller. The casing and the bladder cooperate with each other and are arranged in the borehole, and their positions are moved by pushing and pulling the telescopic rod; the special-shaped spring is fixed in the casing to adjust the positions of the casing and the bladder; the air compressor is connected to the grouting pipeline, and the grouting valve is provided on the grouting pipeline; the pressure gauge monitors the air pressure of the air bag; the borehole detector is inserted into the borehole through the casing to monitor the crushing state of the coal body; and the controller controls the operation of the borehole detector and the grouting tank and controls the grouting to fill the gap. The sleeve includes a first sleeve and a second sleeve, and the pouch includes a first pouch and a second pouch; the first sleeve and the second sleeve are respectively arranged at two ends of the push-pull telescopic rod, the first pouch is sleeved on the first sleeve, and the second pouch is sleeved on the second sleeve; A first grouting valve is provided at the connection between the first bag and the grouting pipeline, and a second grouting valve is provided at the connection between the injection pipeline and the second grouting bag; The air compression device includes an automatic air compression tank, a rotary valve and an air compression pipeline. The automatic air compression tank and the air compression pipeline are connected. The rotary valve is arranged at the air outlet of the automatic air compression tank. The air compression pipeline, the grouting pipeline and the pressure gauge are connected to the three-way valve. The drilling detector includes a camera, a pulley, a spring, a probe and a detection tube. A camera is provided at the front end of the detection tube, and a slurry injection hole is also provided on the detection tube. The spring is arranged between the mounting rod of the pulley and the detection tube, and the probe is connected and fixed by a wooden board on the detection tube.

2. The device for sealing a fixed-point gas extraction borehole multiple times according to claim 1, characterized in that: The first casing and the second casing are sleeved on the gas extraction pipe; the detection pipe of the drilling detector is telescopic along the outer wall of the gas extraction pipe.

3. A method for multiple-point sealed gas extraction drilling, using the device for multiple-point sealed gas extraction drilling according to claim 1 or 2, characterized in that the steps include: S1. Drilling a hole in the coal seam and inserting a casing and a bladder into the hole; S2. Insert the gas extraction pipe into the borehole; S3. Inject gas into the first bag through the grouting line and the first grouting valve. After increasing the injection pressure, the gas fills the first bag. After the injection is complete, close the three-way valve. S4. The controller controls the borehole detector to advance into the borehole, and the camera of the borehole detector detects the borehole wall to determine the coal fracture area; S5. Press the shaped spring, which pushes the second cannula and the second bag to the set position; S6. Inject liquid into the second bag through the injection line. After the second bag is filled with liquid, the plugging slurry is filled under pressure; S7. Continue to control the drilling detector to slide back and forth to determine the coal seam cracks between the first bag and the second bag, and fill the gaps through the slurry injection holes on the detection tube; S8. After the slurry solidifies, gas extraction operations are carried out. After the extraction is completed, the bag and casing are removed and recovered.

4. A method for multiple sealed gas extraction drilling at a fixed point according to claim 3, characterized in that: The first casing is arranged at a distance of 0.5 m from the borehole opening.

5. A method for multiple sealed gas extraction drilling at a fixed point according to claim 3, characterized in that: During the gas extraction operation, when the gas extraction concentration is lower than 0.5%, the extraction is stopped.

Images