A device and method for visualizing the gas extraction drilling hole material can be injected and gas blocking performance of the slow setting or non-setting hole sealing material

Abstract

This invention belongs to the field of gas drainage borehole plugging technology, specifically relating to a device and method for visually evaluating the injectability and gas plugging performance of slow-setting or non-setting grouting materials in gas drainage boreholes. The device includes: a fracture simulation system, a slow-setting or non-setting grouting system, a nitrogen pressurization system, a data acquisition system, and a constant-temperature water bath system. This invention tests the injectability and gas plugging performance of slow-setting or non-setting grouting materials in different openings, angles, and bifurcated fractures by controlling different water bath temperatures. This enables a visual and quantitative evaluation of the injectability and plugging performance of slow-setting or non-setting grouting materials. By changing the fracture type, gas pressure, grouting pressure, and constant-temperature water bath temperature, this invention highly replicates the on-site gas drainage borehole plugging environment, improving the accuracy of evaluating the injectability and plugging performance of slow-setting or non-setting grouting materials. This helps reduce material development costs and improves the safety and economic benefits of gas drainage.

Description

Technical Field

[0001] This invention relates to the field of gas drainage borehole plugging technology, specifically to a device and method for visually evaluating the injectability and gas plugging performance of slow-setting or non-setting sealing materials in gas drainage boreholes. Background Technology

[0002] my country's coal mines are primarily underground, with high coal seam gas content, making them prone to gas explosions and coal and gas outbursts, seriously threatening safe production. As mining depth increases, gas pressure and content rise, making efficient drainage a key measure to reduce disaster risks. However, most mining areas suffer from low drainage efficiency and poor borehole sealing, leading to gas leakage or substandard concentrations, affecting drainage effectiveness. Testing and screening low-cost, high-performance materials can reduce gas drainage costs while improving safety during the process. Borehole material performance testing is a core step in ensuring safe and efficient gas drainage, and is of great significance for reducing gas accidents and promoting efficient mining.

[0003] Currently, sealing materials are mainly divided into two categories: solidified and non-solidified. Solidified materials, such as cement-based materials, polyurethane materials, and high-water-content materials, form rigid or semi-rigid structures through chemical reactions or physical curing, exhibiting high mechanical strength and long-term stability. However, with the development of engineering technology, retarded sealing materials based on sodium-based bentonite and kaolin, as well as non-solidified sealing materials with added water-retaining agents and stabilizers, demonstrate unique advantages in secondary and even multiple sealing scenarios due to their deformability, self-adaptability, and reusability.

[0004] However, existing methods for testing sealing performance, such as permeability measurement and post-sealing leakage measurement, are mainly designed for solidified materials and can only test the sealing performance of single-phase solid sealing materials. Moreover, traditional instruments such as permeability measurement cannot evaluate the sealing effect and injectability of slurry for retarded or non-coagulated sealing materials. When testing the sealing performance of retarded or non-coagulated materials, the volatility and fluidity of these materials can cause them to be blown into the gas line, resulting in blockage and potentially damaging the instruments. Therefore, these testing devices and methods cannot be used for retarded or non-coagulated sealing materials.

[0005] The sealing of fractures in gas drainage boreholes is a black box issue, and the visualization and quantification of the sealing performance testing of retarded or non-condensed sealing materials is even more challenging. The injectability of retarded and non-condensed materials is a prerequisite and foundation for their functionality; however, current technologies for testing retarded or non-condensed sealing materials rely solely on slump and free diffusion behavior without grouting pressure, lacking equipment and methods for evaluating their injectability under actual grouting or gas pressure. This leads to significant discrepancies between laboratory instrument testing and field conditions, frequently resulting in substantial errors between laboratory sealing material performance testing and field applications.

[0006] Currently, there is a serious lack of equipment for injectability testing of slow-setting or non-setting sealing materials, for visual and quantitative evaluation of sealing performance, and for laboratory equipment that can highly replicate the field environment. Summary of the Invention

[0007] This invention addresses the lack of instruments and methods for evaluating the injectability and plugging effectiveness of retarded or non-condensed sealing materials in gas drainage boreholes. It provides a visual evaluation device and method for the injectability and gas plugging performance of retarded or non-condensed sealing materials. The method involves injecting slurry of retarded or non-condensed sealing materials into fractures with different apertures, bending angles, bifurcated fractures, and at different temperatures. The changes in slurry flow loss under different gas pressures are observed to simulate the actual gas plugging state of retarded or non-condensed sealing materials on different fractures under different mine temperatures and gas pressures. This allows for the evaluation of the injectability and plugging performance of retarded or non-condensed sealing materials on different types of fractures. The invention aims to fill the gaps in injectability testing, visualization, and quantitative evaluation of plugging performance of retarded or non-condensed materials, as well as equipment for recreating the field environment. It solves the problems of the lack of injectability testing devices for retarded or non-condensed sealing materials and the difficulty in achieving visualization and quantification of their plugging performance evaluation, providing technical support for the research and selection of new materials.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a visualization evaluation device for the injectability and gas plugging performance of gas extraction borehole slow-setting or non-setting sealing materials, including a fracture simulation system, a constant temperature water bath system, a slow-setting or non-setting grout injection system, a nitrogen pressurization system and a data acquisition system.

[0009] The fracture simulation system includes a straight fracture structure and a bent fracture structure. The straight fracture structure consists of multiple straight fracture glass tubes connected together by pipes. The bent fracture structure includes a circular metal frame, within which bent fracture glass tubes or bifurcated fracture glass tubes are installed. Flow sensors and outlet pipes are connected in series to the outlets of the straight, bent, and bifurcated fracture glass tubes. A high-precision electronic scale is correspondingly installed below each outlet pipe, and a beaker is placed on the high-precision electronic scale.

[0010] The constant temperature water bath system includes a water bath, which is connected to a constant temperature heating device and a temperature sensor. The straight crack structure and the bent crack structure are selectively immersed in the water bath.

[0011] The slow-setting or non-setting grouting system includes a grouting pipeline, a grouting system A, and a grouting system B, wherein either grouting system A or grouting system B is connected to the grouting pipeline. The grouting pipeline includes a grouting pipe, one end of which is connected to a discharge valve, and the other end is connected to multiple grouting branch pipes. Each grouting branch pipe is equipped with a grouting valve and is connected in series with a corresponding glass tube with different creases. The grouting system A includes a nitrogen storage tank and a grout storage tank A, which are connected by an injection pipe. The injection pipe is equipped with a gas pressure regulator and a gas pressure sensor. A stirring rod is installed in the grout storage tank A, which is connected to an outlet pipe for connection with the grouting pipeline. The grouting system B includes a grout storage tank B, which is connected to a grouting pump. The grout storage tank B is also connected to an outlet pipe for connection with the grouting pipeline, and the outlet pipe is equipped with a grouting pressure gauge.

[0012] The nitrogen pressurization system includes a nitrogen storage tank, a gas pressure regulator, an injection pump, a gas pressure sensor, and an injection pipe connected in series via pipelines. The output end of the injection pipe is connected to multiple injection branch pipes, which are respectively connected in series to the grouting branch pipe. Each injection branch pipe is equipped with an injection valve.

[0013] The data acquisition system includes a data acquisition platform, and the gas pressure sensor, temperature sensor, and high-precision electronic scale are all communicatively connected to the data acquisition platform.

[0014] As a further limitation of the technical solution of the present invention, the heating range of the constant temperature water bath system is 0-60℃, and the heating accuracy is 0.3℃; the range of the gas pressure regulator and the gas pressure sensor is 0-25Mpa, and the measurement accuracy is 0.01Mpa.

[0015] As a further limitation of the technical solution of the present invention, the opening dimensions of the straight slit glass tubes are 0.1mm, 0.3mm, 0.5mm, 0.7mm, 1mm, 3mm and 5mm respectively, and the length is 800mm. The straight slit glass tubes are marked with specific lengths. Multiple straight slit glass tubes connected together are fixed with a metal frame, and the upper and lower parts of the metal frame are sealed with visible panels.

[0016] As a further limitation of the technical solution of the present invention, the bending angles of the bent slit glass tubes are 15°, 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135° and 150° respectively. The overall layout of the multiple bent slit glass tubes is designed as a disc, with a diameter of 3mm and a length of 400mm. The bent slit glass tubes are all marked with specific length graduations.

[0017] As a further limitation of the technical solution of the present invention, the bifurcated glass tube is divided into four types: two-branched, three-branched, four-branched, and five-branched, all with a tube diameter of 3mm.

[0018] As a further limitation of the technical solution of the present invention, 24 holes are evenly distributed in a circular metal frame. Different holes are selected to place bent slit glass tubes and branched slit glass tubes at different angles according to the requirements. The straight slit glass tubes, bent slit glass tubes and branched slit glass tubes are all made of transparent glass.

[0019] A visual evaluation method for the injectability of retarded or non-condensing sealing materials in gas drainage boreholes, using the aforementioned visual evaluation device, includes the following steps:

[0020] Step 1: Select the straight fracture structure and grouting system B, connect the systems in sequence, and fix the connection joints with sealing rings; after all systems are connected, close all air injection valves, inject clean water into the B grout storage tank, pressurize the grouting pump to 1 MPa grouting pressure, and conduct a simple test on the air tightness of the test system.

[0021] Step 2: Add the required materials to the B storage tank according to the preset ratio of the retarding or non-setting materials, heat the B storage tank, and at the same time start the constant temperature water bath system to immerse the entire straight-cracked glass tube; open all grouting valves, and use the grouting pump to push the grout through the grouting branch pipe into the straight-cracked glass tubes with different openings at a grouting pressure of 0.6 MPa.

[0022] Step 3: ① Activate the constant temperature heating device to control the temperature of the constant temperature water bath at 10°C, 20°C, and 30°C respectively. Simulate the migration of slow-setting or non-setting slurry in fractures of different opening sizes under different mine temperatures. Observe the flow of slow-setting or non-setting slurry in straight fracture glass tubes of different opening sizes, and record the diffusion distance of the slurry according to the scale on the glass tube. Quantify the injectability at different temperatures using the flow distance and velocity of the slurry.

[0023] ,

[0024] Q - Flow velocity, W - Flow distance, T - Flow time

[0025] ② Tilt the entire straight fracture glass tube and constant temperature water bath at 15°, 30°, 45°, 60°, 75°, and 90° respectively, or invert the entire straight fracture structure to simulate the migration path of slow-setting or non-setting grout in boreholes at different angles. Record the diffusion distance of the grout and the height of the grout tip from the ground according to the scale on the straight fracture glass tube to quantify the injectability of slow-setting or non-setting grout in different migration directions. The larger the H value, the better the injectability.

[0026] H=D*sinθ,

[0027] H - transport height, D - flow distance, θ - tilt angle.

[0028] A method for visually evaluating the gas plugging performance of retarded or non-condensable sealing materials in gas drainage boreholes, using the aforementioned visualization evaluation device, to evaluate the plugging effect of retarded or non-condensable materials on straight fractures, includes the following steps:

[0029] Step 1: Select the straight fracture structure and grouting system B, connect the systems in sequence, and fix the connection joints with sealing rings. After all systems are connected, close all air injection valves, inject clean water into the B grout storage tank, pressurize the grouting pump to 1 MPa grouting pressure, and conduct a simple test on the air tightness of the test system.

[0030] Step 2: Then replace grouting system B with grouting system A. Add the required materials to grout storage tank A according to the preset ratio of retarding or non-setting materials. Start the stirring rod to continuously stir the grout. Heat grout storage tank A and start the constant temperature water bath system at the same time. The constant temperature water bath immerses the entire straight fracture structure. Set the target temperature to 15°C~35°C and record it by data acquisition platform 1. Maintain the constant temperature for 30 minutes. Temperature sensor 11 detects the temperature in real time.

[0031] Step 3: Open all grouting valves and use the gas pressure regulator to slowly inject the grout into the straight-cracked glass tubes of different openings through a certain nitrogen gas pressure. After the grout fills each straight-cracked glass tube, close the grouting valves on each grouting branch pipe and let it stand for 10 minutes after grouting.

[0032] Step 4: Open the gas injection valve on the gas injection branch pipe, and inject nitrogen from the nitrogen storage tank into the straight slit glass tubes with different openings at a pressure of 0.6MPa through the gas pressure regulator. Use the gas pressure to blow the slurry through the flow sensor and the slurry outlet pipe to the high-precision electronic scale containing the beaker, and detect the gas pressure through the gas pressure sensor.

[0033] Step 5: Use the data acquisition platform to automatically collect mass, pressure, and temperature data transmitted by the high-precision electronic scale, gas pressure sensor, and temperature sensor; comprehensively evaluate the sealing performance of the retarded or non-retarded sealing material based on the nitrogen pressure P, slurry extrusion rate M, and constant temperature water bath temperature C: the larger the K value, the better the sealing effect of the slurry.

[0034] ,

[0035] P - nitrogen pressure, M - slurry extrusion rate, C - water bath temperature;

[0036] Step 6: After the test is completed, open the drain valve to drain the residual slurry from the A storage tank and the grouting pipe, and rinse with clean water three times. Disassemble washable parts (such as the stirring rod and the fracture module), and use a soft brush to remove the adhering slurry. Finally, use compressed air to dry the pipeline and thoroughly clean the test system.

[0037] A method for visually evaluating the gas plugging performance of retarded or non-condensable sealing materials in gas extraction boreholes, using the aforementioned visualization evaluation device, to evaluate the plugging effect of retarded or non-condensable materials on bending cracks, includes the following steps:

[0038] Step 1: Select the bent fracture structure and grouting system B. Install the bent fracture glass tube inside the circular metal frame, connect the systems in sequence, and fix the connection joints with sealing rings. After all systems are connected, close all air injection valves, inject clean water into the B grout storage tank, pressurize the grouting pump to 1 MPa grouting pressure, and conduct a simple test on the air tightness of the test system.

[0039] Step 2: Add the required materials to the A storage tank according to the preset ratio of slow-setting or non-setting materials, and start the stirring rod to continuously stir the slurry; heat the A storage tank, and at the same time start the constant temperature water bath system. The water bath should immerse the entire bent crack structure, set the target temperature to 15°C~35°C, maintain the constant temperature for 30 minutes, and the temperature sensor should detect the temperature in real time.

[0040] Step 3: Open all grouting valves and use the gas pressure regulator to slowly inject the grout into the glass tubes with different angles of bends and fractures by pushing the grout through a certain nitrogen gas pressure. After the grout fills each glass tube, close the grouting valves on each grouting branch pipe and let it stand for 10 minutes after grouting.

[0041] Step 4: Open the gas injection valve on the gas injection branch pipe, and inject nitrogen from the nitrogen storage tank into the glass tubes with bends at different angles at a pressure of 0.6MPa through the gas pressure regulator. Use the gas pressure to blow the slurry out through the flow meter slurry pipe to the high-precision electronic scale containing the beaker, and detect the gas pressure through the gas pressure sensor.

[0042] Step 5: Use the data acquisition platform to automatically collect mass, pressure, temperature and other data transmitted by high-precision electronic scale, gas pressure sensor and temperature sensor; comprehensively evaluate the sealing performance of retarded or non-setting materials based on nitrogen pressure P, slurry extrusion amount M and constant temperature water bath temperature C. The larger the K value, the better the sealing effect of the slurry.

[0043] ,

[0044] P - nitrogen pressure, M - slurry extrusion rate, C - water bath temperature;

[0045] Step Six: After the test is completed, open the drain valve to drain the residual slurry from the slurry storage tank and grouting pipe, and rinse with clean water circulation 3 times; disassemble washable parts and use a soft brush to remove the adhering slurry; finally, use compressed air to dry the pipeline and thoroughly clean the test system.

[0046] Step 7: Replace the bent slit glass tube installed inside the circular metal frame with a branched slit glass tube, and repeat steps 1 to 6 above.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] 1. This device and method overcome the shortcomings of traditional test devices and methods that cannot be used to evaluate the injectability and plugging performance of slow-setting or non-setting sealing materials in gas drainage boreholes.

[0049] 2. This invention utilizes a constant temperature water bath system to overcome the difficulty of traditional devices failing to accurately replicate the gas extraction borehole sealing environment in a mine.

[0050] 3. Traditional devices cannot visualize the evaluation of the sealing effect of retarded or non-coagulated materials. The device of this invention uses a transparent glass tube and an acrylic sealing plate to directly observe the pressure diffusion of the slurry of retarded or non-coagulated materials under different temperatures and gas pressures, which can visualize the evaluation of the injectability and sealing performance of retarded or non-coagulated sealing materials.

[0051] 4. Traditional devices cannot quantify the evaluation of the sealing effect of retarded or non-condensed materials. However, this invention uses formulas to calculate the diffusion rate, distance and height of retarded or non-condensed materials at different openings, angles and bifurcated cracks, which can quantify the evaluation of the injectability and sealing performance of retarded or non-condensed sealing materials.

[0052] 5. This invention, by changing the type of fracture (aperture, angle, bifurcation), gas pressure, grouting pressure, and constant temperature water bath temperature, highly replicates the on-site gas drainage borehole sealing environment, which can improve the accuracy of evaluating the injectability and sealing performance of slow-setting or non-setting sealing materials. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the overall structure of the evaluation device of the present invention.

[0054] Figure 2 This is a diagram of the injectability testing apparatus.

[0055] Figure 3 This is a schematic diagram showing the replacement of the testing device for straight cracks and curved cracks.

[0056] Figure 4 It is a diagram of a bending crack test disk.

[0057] Figure 5This is a diagram of a glass tube with bifurcated and bent fissures.

[0058] Figure 6 This is a magnified view of a section of a glass tube with a bend and crack.

[0059] Figure 7 This is a diagram of a bifurcation crack test disk.

[0060] The markings in the image are as follows:

[0061] 1. Data acquisition platform; 2. Constant temperature heating device; 3. Nitrogen storage tank; 4. Gas pressure regulator; 5. Gas injection pump; 6. Gas injection pipe; 7. Gas pressure sensor; 8. Gas injection valve; 9. Gas injection branch pipe; 10. Flow sensor; 11. Temperature sensor; 12. Grouting valve; 13. Grouting branch pipe; 14. Grouting pipe; 15. Straight cracked glass tube; 16. Constant temperature water bath; 17. High-precision electronic scale; 18. Beaker; 19. Grout outlet pipe; 20. Stirring rod; 21. A grout storage tank; 22. Gas injection pipe; 23. Gas pressure sensor; 24. Gas pressure regulator; 25. Nitrogen storage tank; 26. Liquid discharge valve; 27. Grouting pressure gauge; 28. B grout storage tank; 29. ​​Grouting pump; 30. Circular metal frame; 31. Bent cracked glass tube; 32. Grouting port; 33. Grout outlet; 34. Bifurded cracked glass tube. Detailed Implementation

[0062] The present invention will be further described below with reference to specific embodiments.

[0063] like Figure 1 As shown, a visualization evaluation device for the injectability and gas plugging performance of gas drainage borehole retarded or non-condensed sealing materials includes a fracture simulation system, a constant temperature water bath system, a retarded or non-condensed grout injection system, a nitrogen pressurization system, and a data acquisition system.

[0064] The fracture simulation system includes a straight fracture structure and a bent fracture structure. The straight fracture structure consists of multiple straight fracture glass tubes 15 connected together by pipes. The bent fracture structure includes a circular metal frame 30, within which bent fracture glass tubes 31 or branched fracture glass tubes 34 are installed. A flow sensor 10 and a discharge pipe 19 are connected in series to the outlets of the straight fracture glass tubes 15, bent fracture glass tubes 31, and branched fracture glass tubes 34. A high-precision electronic scale 17 is correspondingly installed below the discharge pipe 19, and a beaker 18 is placed on the high-precision electronic scale 17. The corresponding fracture testing disk of the bent fracture structure is as follows: Figure 3 , Figure 4 and Figure 7 As shown.

[0065] The constant temperature water bath system includes a water bath 16, which is connected to a constant temperature heating device 2 and a temperature sensor 11. The straight crack structure and the bent crack structure are selectively immersed in the water bath 16 for heating and maintaining a constant temperature. The heating range of the constant temperature water bath system is 0-60℃, and the heating accuracy is 0.3℃.

[0066] The slow-setting or non-setting grouting system includes a grouting pipeline, a grouting system A, and a grouting system B, wherein either grouting system A or grouting system B is connected to the grouting pipeline. The grouting pipeline includes a grouting pipe 14, one end of which is connected to a drain valve 26, and the other end is connected to multiple grouting branch pipes 13. Each grouting branch pipe 13 is equipped with a grouting valve 12, and the grouting branch pipes 13 are connected in series with corresponding glass tubes with different creases. The grouting system A includes a nitrogen storage tank 25 and a grout storage tank A 21, and the two are connected by a gas injection pipe 22. The gas injection pipe 22 is equipped with a gas pressure regulator 24 and a gas pressure sensor 23. The range of the gas pressure regulator 24 and the gas pressure sensor 23 is 0-25 MPa, and the measurement accuracy is 0.01 MPa. A stirring rod 20 is installed in slurry storage tank A 21, and slurry outlet pipe is connected to slurry injection pipe 14; the grouting system B includes slurry storage tank B 28, slurry storage tank B 28 is connected to grouting pump 29, grouting pressure range of 0-3 MPa, accuracy of 0.03 MPa; slurry storage tank B 28 is also connected to slurry outlet pipe for connection to grouting pipe 14, and grouting pressure gauge 27 is installed on slurry outlet pipe;

[0067] The nitrogen pressurization system includes a nitrogen storage tank 3, a gas pressure regulator 4, an injection pump 5, a gas pressure sensor 7, and an injection pipe 6 connected in series by pipelines. The output end of the injection pipe 6 is connected to multiple injection branch pipes 9, which are respectively connected in series to the grouting branch pipe 13. Each injection branch pipe 9 is equipped with an injection valve 8.

[0068] The data acquisition system includes a data acquisition platform 1. The gas pressure sensor 7, temperature sensor 11, and high-precision electronic scale 17 are all connected to the data acquisition platform 1 for communication. The system uses acquisition software to acquire real-time data such as mass, pressure, and temperature.

[0069] The aforementioned grouting system for slow-setting or non-setting materials and nitrogen pressurization system are connected in series with the crack simulation system. The straight crack test structure can be replaced by the bent crack test disk and the bifurcated crack test disk. The bent crack glass tube 31 and the bifurcated crack glass tube 34 in the circular metal frame 30 can also be replaced.

[0070] Furthermore, the opening dimensions of the straight slit glass tubes 15 are 0.1mm, 0.3mm, 0.5mm, 0.7mm, 1mm, 3mm and 5mm respectively, and the length is 800mm. The straight slit glass tubes 15 are marked with specific lengths. Multiple straight slit glass tubes 15 connected together are fixed with a metal frame, and the top and bottom of the metal frame are sealed with visible panels.

[0071] Furthermore, such as Figure 6 As shown, the bending angles of the bent slit glass tubes 31 are 15°, 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135° and 150° respectively. The overall layout of the multiple bent slit glass tubes 31 is designed as a disc, with a diameter of 3mm and a length of 400mm. Each bent slit glass tube 31 is marked with a specific length.

[0072] Furthermore, such as Figure 5 As shown, the bifurcated glass tube 34 is divided into four types: bifurcated, trifurcated, quadrifurcated, and pentafurcated, all with a diameter of 3mm.

[0073] Furthermore, such as Figure 4 As shown, the circular metal frame 30 has 24 evenly distributed holes. Different holes can be selected to hold bent slit glass tubes 31 and branched slit glass tubes 34 at different angles, depending on the requirements. The straight slit glass tube 15, the bent slit glass tube 31, and the branched slit glass tube 34 are all made of transparent glass. Example 1

[0074] Example 1

[0075] A visual evaluation method for the injectability of retarded or non-condensing sealing materials in gas drainage boreholes, employing the aforementioned visual evaluation device (such as...). Figure 2 The process includes the following steps:

[0076] Step 1: Select the straight fracture structure and grouting system B, connect the systems in sequence, and fix the connection joints with sealing rings; after all systems are connected, close all air injection valves 8, inject clean water into grout storage tank 28, pressurize grouting pump 29 to 1 MPa grouting pressure, and conduct a simple test on the air tightness of the test system.

[0077] Step 2: Add the required materials to the B storage tank 28 according to the preset ratio of the slow-setting or non-setting materials, heat the B storage tank 28, and at the same time start the constant temperature water bath system to immerse the entire straight-cracked glass tube; open all the grouting valves 12, and use the grouting pump 29 to push the grout through the grouting branch pipe 13 to inject the grout into the straight-cracked glass tubes 15 with different openings at a grouting pressure of 0.6 MPa.

[0078] Step 3: ① Start the constant temperature heating device 2 to control the temperature of the constant temperature water bath 16 to 10°C, 20°C, and 30°C respectively, to simulate the movement of slow-setting or non-setting slurry in fractures of different opening sizes under different mine temperatures. Observe the flow of slow-setting or non-setting slurry in the straight fracture glass tube 15 of fractures of different opening sizes, and record the diffusion distance of the slurry according to the scale on the glass tube. Quantify the injectability at different temperatures using the flow distance and velocity of the slurry.

[0079] ,

[0080] Q - flow velocity, W - flow distance, T - flow time;

[0081] The results are shown in Table 1.

[0082] Table 1

[0083]

[0084] ② Tilt the entire straight fracture glass tube 15 and the constant temperature water bath 16 at 15°, 30°, 45°, 60°, 75°, and 90° respectively, or invert the entire straight fracture structure to simulate the migration path of slow-setting or non-setting grout in boreholes at different angles. Record the diffusion distance of the grout and the height of the grout tip from the ground according to the scale on the straight fracture glass tube 15 to quantify the injectability of slow-setting or non-setting grout in different migration directions. The larger the H value, the better the injectability.

[0085] H=D*sinθ,

[0086] H - transport height, D - flow distance, θ - tilt angle.

[0087] The results are shown in Table 2.

[0088] Table 2

[0089] .

[0090] Example 2

[0091] A method for visually evaluating the gas plugging performance of retarded or non-condensable sealing materials in gas drainage boreholes, using the aforementioned visualization evaluation device, to evaluate the plugging effect of retarded or non-condensable materials on straight fractures, includes the following steps:

[0092] Step 1: Select the straight fracture structure and grouting system B, connect the systems in sequence, and fix the connection joints with sealing rings. After all systems are connected, close all air injection valves 8, inject clean water into grout storage tank 28, pressurize grouting pump 29 to 1 MPa grouting pressure, and conduct a simple test on the air tightness of the test system.

[0093] Step 2: Then replace grouting system B with grouting system A, add the required materials to grout storage tank 21 in sequence according to the preset ratio of retarding or non-setting materials, and start the stirring rod 20 to continuously stir the grout; heat grout storage tank 21, and at the same time start the constant temperature water bath system. The constant temperature water bath 16 immerses the entire straight fracture structure, sets the target temperature to 15°C~35°C and records it by the data acquisition platform 1, maintains the constant temperature for 30 minutes, and the temperature sensor 11 detects the temperature in real time.

[0094] Step 3: Open all grouting valves 12 and use the gas pressure regulator 24 to push the grout through a certain nitrogen gas pressure to slowly inject the slow-setting or non-setting grout into the straight-cracked glass tubes 15 with different openings. After the grout fills each straight-cracked glass tube 15, close the grouting valves 12 on each grouting branch pipe and let it stand for 10 minutes after grouting.

[0095] Step 4: Open the gas injection valve 8 on the gas injection branch pipe 9, and inject the nitrogen in the nitrogen storage tank 3 into the straight slit glass tubes 15 with different openings at a pressure of 0.6MPa through the gas pressure regulator 4. Use the gas pressure to blow the slurry through the flow sensor 10 and the slurry outlet pipe 19 to the high-precision electronic scale 17 containing the beaker 18, and detect the gas pressure through the gas pressure sensor 7.

[0096] Step 5: Automatically collect mass, pressure, and temperature data transmitted by the high-precision electronic scale 17, gas pressure sensor 7, and temperature sensor 11 using the data acquisition platform 1; comprehensively evaluate the sealing performance of the slow-setting or non-setting sealing material based on the nitrogen pressure P, slurry extrusion rate M, and constant temperature water bath temperature C: the larger the K value, the better the sealing effect of the slurry.

[0097] ,

[0098] P - nitrogen pressure, M - slurry extrusion rate, C - water bath temperature;

[0099] The measured values ​​of P were 0.8 MPa, M was 150 g, and C was 30 °C. The calculated value of K was 6.25.

[0100] Step 6: After the test is completed, open the drain valve 26 to drain the residual slurry from the A slurry tank 21 and the grouting pipe, and rinse with clean water three times. Disassemble washable parts (such as the stirring rod and the fracture module), and use a soft brush to remove the adhering slurry. Finally, use compressed air to dry the pipeline and thoroughly clean the test system.

[0101] Example 3

[0102] A method for visually evaluating the gas plugging performance of retarded or non-condensable sealing materials in gas extraction boreholes, using the aforementioned visualization evaluation device, to evaluate the plugging effect of retarded or non-condensable materials on bending cracks, includes the following steps:

[0103] Step 1: Select the bent fracture structure and grouting system B. The bent fracture glass tube 31 is installed inside the circular metal frame 30. Connect the systems in sequence and fix the connection ports with sealing rings. After all systems are connected, close all air injection valves 8, inject clean water into the B grout storage tank 28, pressurize the grouting pump 29 to 1 MPa grouting pressure, and conduct a simple test on the air tightness of the test system.

[0104] Step 2: Add the required materials to the A storage tank 21 in sequence according to the preset ratio of slow-setting or non-setting materials, and start the stirring rod 20 to continuously stir the slurry; heat the A storage tank 21, and at the same time start the constant temperature water bath system. The water bath 16 immerses the entire bent crack structure, sets the target temperature to 15°C~35°C, maintains the constant temperature for 30 minutes, and the temperature sensor 11 detects the temperature in real time.

[0105] Step 3: Open all grouting valves 12 and use the gas pressure regulator 24 to push the grout through a certain nitrogen gas pressure to slowly inject the slow-setting or non-setting grout into the bend-cracked glass tubes 31 at different angles. After the grout fills each bend-cracked glass tube 31, close the grouting valves 12 on each grouting branch pipe and let it stand for 10 minutes after grouting.

[0106] Step 4: Open the gas injection valve 8 on the gas injection branch pipe 9, and inject the nitrogen in the nitrogen storage tank 3 into the glass tubes 31 with different angles at a pressure of 0.6MPa through the gas pressure regulator 4. Use the gas pressure to blow the slurry out of the slurry outlet pipe 19 through the flow sensor 10 to the high-precision electronic scale 17 with the beaker 18 placed on it, and use the gas pressure sensor 7 to detect the gas pressure.

[0107] Step 5: Automatically collect mass, pressure, and temperature data transmitted by the high-precision electronic scale 17, gas pressure sensor 7, and temperature sensor 11 using the data acquisition platform 1; comprehensively evaluate the sealing performance of the retarding or non-setting materials based on the nitrogen pressure P, slurry extrusion amount M, and constant temperature water bath temperature C: the larger the K value, the better the pore sealing effect of the slurry.

[0108] ,

[0109] P - nitrogen pressure, M - slurry extrusion rate, C - water bath temperature;

[0110] The measured values ​​of P were 0.5 MPa, M was 110 g, and C was 28 °C. The calculated value of K was 7.857.

[0111] Step Six: After the test is completed, open the drain valve to drain the residual slurry from the slurry storage tank and grouting pipe, and rinse with clean water circulation 3 times; disassemble washable parts and use a soft brush to remove the adhering slurry; finally, use compressed air to dry the pipeline and thoroughly clean the test system.

[0112] Step 7: Replace the bent slit glass tube 31 installed inside the circular metal frame 30 with the bifurcated slit glass tube 34, and repeat steps one to six above; P is measured to be 0.35 MPa, M is 96 g, C is 31 °C, and K is calculated to be 8.848.

[0113] Example 4

[0114] Evaluation method for sealing effectiveness of retarded or non-retarded materials under mining influence, including the following steps:

[0115] Step 1: Select the straight fracture structure and grouting system B, connect the systems in sequence, and fix the connection joints with sealing rings. After all systems are connected, close all air injection valves 8, inject clean water into grout storage tank 28, pressurize grouting pump 29 to 1 MPa grouting pressure, and conduct a simple test on the air tightness of the test system.

[0116] Step 2: Then replace grouting system B with grouting system A, add the required materials to grout storage tank 21 in sequence according to the preset ratio of retarding or non-setting materials, and start the stirring rod 20 to continuously stir the grout; heat grout storage tank 21, and at the same time start the constant temperature water bath system. The constant temperature water bath 16 immerses the entire straight fracture structure, sets the target temperature to 15°C~35°C and records it by the data acquisition platform 1, maintains the constant temperature for 30 minutes, and the temperature sensor 11 detects the temperature in real time.

[0117] Step 3: Open all grouting valves 12 and use the gas pressure regulator 24 to slowly inject the grout, either slow-setting or non-setting, into the straight-cracked glass tubes 15 with different openings through a certain nitrogen gas pressure. After the grout fills each straight-cracked glass tube 15, close the grouting valves 12 on each grouting branch pipe. Let it stand for 10 minutes after grouting. Depending on the ratio of slow-setting or non-setting materials, it can stand for 24 to 72 hours.

[0118] Step 4: Install the bifurcated glass tube 34 onto the grout outlet pipe 19; open all grouting valves 12 to inject retarded or non-retarded grout into the straight glass tube 15 for the second time, while observing the flow of the retarded or non-retarded grout in the bifurcated glass tube 34. The flow distance S of the retarded or non-retarded grout in the bifurcated glass tube is equal to the sum of the flow distance L of the grout in each branch of the bifurcated glass tube; the larger the value of S, the better the sealing effect.

[0119] For example, a three-pronged slit tube: S = L1 + L2 + L3 = 15cm + 16.3cm + 11cm = 42.3cm.

Claims

1. A device for visualizing the injectability and gas sealing performance of a slow-setting or non-setting sealing material for a gas extraction borehole, characterized in that This includes a fracture simulation system, a constant temperature water bath system, a slow-setting or non-setting grout injection system, a nitrogen pressurization system, and a data acquisition system. The fracture simulation system includes a straight fracture structure and a bent fracture structure. The straight fracture structure consists of multiple straight fracture glass tubes (15) connected together by pipes. The bent fracture structure includes a circular metal frame (30), and a bent fracture glass tube (31) or a bifurcated fracture glass tube (34) is installed inside the circular metal frame (30). The outlets of the straight fracture glass tube (15), the bent fracture glass tube (31), and the bifurcated fracture glass tube (34) are all connected in series with a flow sensor (10) and an outlet pipe (19). A high-precision electronic scale (17) is correspondingly provided under the outlet pipe (19), and a beaker (18) is placed on the high-precision electronic scale (17). The constant temperature water bath system includes a water bath (16), the water bath (16) is connected to a constant temperature heating device (2) and a temperature sensor (11), and one of the straight crack structure and the bent crack structure is immersed in the water bath (16); The slow-setting or non-setting grouting system includes a grouting pipeline, a grouting system A, and a grouting system B, wherein either grouting system A or grouting system B is connected to the grouting pipeline. The grouting pipeline includes a grouting pipe (14), one end of which is connected to a drain valve (26), and the other end is connected to multiple grouting branch pipes (13). Each grouting branch pipe (13) is equipped with a grouting valve (12), and the grouting branch pipes (13) are connected in series with corresponding glass tubes with different creases. The grouting system A includes a nitrogen storage tank (25) and a grout storage tank A (21). The two are connected by an air injection pipe (22), and the air injection pipe (22) is equipped with a gas pressure regulator (24) and a gas pressure sensor (23). A stirring rod (20) is installed in the A slurry tank (21), and the A slurry tank (21) is connected to a slurry outlet pipe for connection with the grouting pipe (14). The grouting B system includes a B slurry tank (28), which is connected to a grouting pump (29). The B slurry tank (28) is also connected to a slurry outlet pipe for connection with the grouting pipe (14), and a grouting pressure gauge (27) is installed on the slurry outlet pipe. The nitrogen pressurization system includes a nitrogen storage tank (3), a gas pressure regulator (4), an injection pump (5), a gas pressure sensor (7), and an injection pipe (6) connected in series by pipelines. The output end of the injection pipe (6) is connected to multiple injection branch pipes (9), which are respectively connected in series to the grouting branch pipe (13). Each injection branch pipe (9) is equipped with an injection valve (8). The data acquisition system includes a data acquisition platform (1), and the gas pressure sensor (7), temperature sensor (11) and high-precision electronic scale (17) are all connected to the data acquisition platform (1) for communication.

2. The device according to claim 1, characterized in that, The constant temperature water bath system has a heating range of 0-60℃ and a heating accuracy of 0.3℃; the gas pressure regulator (24) and the gas pressure sensor (23) have a range of 0-25Mpa and a measurement accuracy of 0.01Mpa.

3. The device according to claim 1, characterized in that, The opening dimensions of the straight slit glass tubes (15) are 0.1mm, 0.3mm, 0.5mm, 0.7mm, 1mm, 3mm and 5mm respectively, and the length is 800mm. The straight slit glass tubes (15) are marked with specific lengths. Multiple straight slit glass tubes (15) connected together are fixed with a metal frame, and the metal frame is sealed with a visible panel at the top and bottom.

4. The device according to claim 1, characterized in that, The bending angles of the folded glass tubes (31) are 15°, 30°, 45°, 60°, 75°, 90°, 105°, 120°, 135° and 150° respectively. The diameter of each tube is 3mm and the length is 400mm. The folded glass tubes (31) are marked with specific lengths. The overall layout of the multiple folded glass tubes (31) is designed as a disc.

5. The device according to claim 1, characterized in that, The bifurcated glass tube (34) is divided into four types: bifurcated, trifurcated, quadrifurcated and pentafurcated, with a tube diameter of 3mm.

6. The device according to claim 1, characterized in that, The circular metal frame (30) has 24 holes evenly distributed. Different holes are selected to place bent slit glass tubes (31) and bifurcated slit glass tubes (34) at different angles according to the requirements. The straight slit glass tube (15), bent slit glass tube (31) and bifurcated slit glass tube (34) are all made of transparent glass.

7. A method for visually evaluating the injectability of retarded or non-condensing sealing materials in gas drainage boreholes, comprising using the visual evaluation device as described in any one of claims 1-6, characterized in that... Includes the following steps: Step 1: Select the straight crack structure and grouting system B, connect the systems in sequence, and fix the connection with a sealing ring; after the connection of each system is completed, close all air injection valves (8), inject clean water into the B grout storage tank (28), pressurize the grouting pump (29) to 1 MPa grouting pressure, and conduct a simple test on the air tightness of the test system; Step 2: Add the required materials to the B storage tank (28) in sequence according to the preset ratio of slow-setting or non-setting materials, heat the B storage tank (28), and at the same time start the constant temperature water bath system to immerse the entire straight-cracked glass pipeline; open all grouting valves (12), and use the grouting pump (29) to push the grout through the grouting branch pipe (13) to inject the grout into the straight-cracked glass pipeline (15) with different openings through the grouting pressure of 0.6Mpa. Step 3: ① Start the constant temperature heating device (2) and control the temperature of the constant temperature water bath (16) to be 10°C, 20°C and 30°C respectively. Simulate the movement of slow-setting or non-setting slurry in different opening fractures under different mine temperatures, observe the flow of slow-setting or non-setting slurry in the straight fracture glass tube (15) under different opening fractures, and record the diffusion distance of the slurry according to the scale on the glass tube. Quantify the injectability at different temperatures by the flow distance and speed of the slurry: ， Q - flow velocity, W - flow distance, T - flow time; ② Tilt the entire straight fracture glass tube (15) and constant temperature water bath (16) at 15°, 30°, 45°, 60°, 75° and 90° respectively, or invert the entire straight fracture structure to simulate the migration path of slow-setting or non-setting slurry in boreholes at different angles, and record the diffusion distance of the slurry and the height of the slurry tip from the ground according to the scale on the straight fracture glass tube (15) to quantify the injectability of slow-setting or non-setting slurry in different migration directions. The larger the H value, the better the injectability. H=D*sinθ, H - transport height, D - flow distance, θ - tilt angle.

8. A method for visually evaluating the gas plugging performance of condensing or non-condensing sealing materials in gas drainage boreholes, comprising using the visual evaluation device as described in any one of claims 1-6, characterized in that... Evaluation of the sealing effect of retarded or non-setting materials on straight cracks includes the following steps: Step 1: Select the straight crack structure and grouting system B, connect the systems in sequence, and fix the connection with a sealing ring. After the system is connected, close all air injection valves (8), inject clean water into the B grout storage tank (28), pressurize the grouting pump (29) to 1 MPa grouting pressure, and conduct a simple test on the air tightness of the test system. Step 2: Then replace the grouting system B with the grouting system A, add the required materials to the grout storage tank A (21) in sequence according to the preset ratio of slow-setting or non-setting materials, start the stirring rod (20) to continuously stir the grout; heat the grout storage tank A (21), and at the same time start the constant temperature water bath system. The constant temperature water bath (16) immerses the entire straight crack structure, sets the target temperature to 15°C~35°C and records it by the data acquisition platform (1), maintains the constant temperature for 30 minutes, and the temperature sensor (11) detects the temperature in real time. Step 3: Open all grouting valves (12) and use the gas pressure regulator (24) to push the grout through a certain nitrogen gas pressure to slowly inject the slow-setting or non-setting grout into the straight-cracked glass tubes (15) with different openings. After the grout fills each straight-cracked glass tube (15), close the grouting valves (12) on each grouting branch pipe and let it stand for 10 minutes after grouting. Step 4: Open the gas injection valve (8) on the gas injection branch pipe (9), and inject the nitrogen in the nitrogen storage tank (3) into the straight crack glass tubes (15) with different openings at a pressure of 0.6MPa through the gas pressure regulator (4). Use the gas pressure to blow the slurry through the flow sensor (10) and the slurry outlet pipe (19) to the high-precision electronic scale (17) with the beaker (18) on it, and detect the gas pressure through the gas pressure sensor (7). Step 5: Use the data acquisition platform (1) to automatically collect the mass, pressure and temperature data transmitted by the high-precision electronic scale (17), gas pressure sensor (7) and temperature sensor (11); evaluate the sealing performance of the slow-setting or non-setting sealing material based on the nitrogen pressure P, slurry extrusion amount M and constant temperature water bath temperature C: the larger the K value, the better the sealing effect of the slurry. ， P - nitrogen pressure, M - slurry extrusion rate, C - water bath temperature; Step 6: After the test is completed, open the drain valve (26) to drain the residual slurry in the A storage tank (21) and the grouting pipe, and rinse with clean water three times. Disassemble the washable parts and remove the adhering slurry with a soft brush. Finally, use compressed air to dry the pipeline and thoroughly clean the test system.

9. A method for visually evaluating the gas plugging performance of condensing or non-condensing sealing materials in gas drainage boreholes, comprising using the visual evaluation device as described in any one of claims 1-6, characterized in that... The evaluation of the sealing effect of retarded or non-setting materials on bending cracks includes the following steps: Step 1: Select the bent crack structure and grouting system B. Install the bent crack glass tube (31) inside the circular metal frame (30), connect the systems in sequence, and fix the connection with a sealing ring. After the systems are connected, close all air injection valves (8), inject clean water into the B grout tank (28), pressurize the grouting pump (29) to 1 MPa grouting pressure, and conduct a simple test on the air tightness of the test system. Step 2: Add the required materials to the A storage tank (21) in sequence according to the preset ratio of slow-setting or non-setting materials, and start the stirring rod (20) to continuously stir the slurry; heat the A storage tank (21), and at the same time start the constant temperature water bath system. The water bath (16) immerses the entire bent crack structure, sets the target temperature to 15°C~35°C, maintains the constant temperature for 30 minutes, and the temperature sensor (11) detects the temperature in real time. Step 3: Open all grouting valves (12) and use the gas pressure regulator (24) to push the grout through a certain nitrogen gas pressure to slowly inject the slow-setting or non-setting grout into the bend-cracked glass tubes (31) at different angles. After the grout fills each bend-cracked glass tube (31), close the grouting valves (12) on each grouting branch pipe and let it stand for 10 minutes after grouting. Step 4: Open the gas injection valve (8) on the gas injection branch pipe (9), and inject the nitrogen in the nitrogen storage tank (3) into the glass tubes (31) with different angles at a pressure of 0.6MPa through the gas pressure regulator (4). Use the gas pressure to blow the slurry out through the slurry outlet pipe (19) of the flow sensor (10) to the high-precision electronic scale (17) with the beaker (18) on it, and detect the gas pressure through the gas pressure sensor (7). Step 5: Use the data acquisition platform (1) to automatically collect the mass, pressure and temperature data transmitted by the high-precision electronic scale (17), gas pressure sensor (7) and temperature sensor (11); evaluate the sealing performance of the retarding or non-coagulating materials based on the nitrogen pressure P, slurry extrusion amount M and constant temperature water bath temperature C: the larger the K value, the better the sealing effect of the slurry. ， P - nitrogen pressure, M - slurry extrusion rate, C - water bath temperature; Step Six: After the test is completed, open the drain valve to drain the residual slurry from the slurry storage tank and grouting pipe, and rinse with clean water circulation 3 times; disassemble washable parts and use a soft brush to remove the adhering slurry; finally, use compressed air to dry the pipeline and thoroughly clean the test system. Step 7: Replace the bent slit glass tube (31) installed inside the circular metal frame (30) with a bifurcated slit glass tube (34), and repeat steps one to six above.

Images