CN207194943U - A kind of Drillhole gas pumping laboratory analog system - Google Patents

Abstract

The utility model discloses a kind of multipurpose Drillhole gas pumping laboratory analog system, including borehole simulation pipe, hole-sealing grouting system, gas pressure simulated loading system, gas detector, acoustic emission system and computer；Two is provided with plug model configuration in borehole simulation pipe, and the tube wall of borehole simulation pipe is provided with multiple cracks simulation hole, simulation pipe in crack is connected with the simulation hole of crack, gas leakage detection switch is connected with crack simulation pipe；Hole-sealing grouting system includes Grouting Pipe, slurry recovering tube, grouting pump, slip casting handle and grouting pressure table；Gas pressure simulated loading system includes vavuum pump, methane gas tank, pressure vacuum gauge, vacuum switch, methane gas tank switch, gas pressure table and gas pumping switch.It is convenient that the utility model is realized, can real simulation field condition, and the experiment for needing to do at the scene is moved in laboratory, tests that the manpower and materials of consuming are few, and experiment effect is good, the accuracy of experimental result is high, practical.

Description

A Multipurpose Borehole Gas Drainage Laboratory Simulation System

technical field

The utility model belongs to the technical field of borehole gas drainage, and in particular relates to a multipurpose multipurpose borehole gas drainage laboratory simulation system.

Background technique

In most areas of my country, coal seams have high gas content, high pressure, low coal seam permeability, and complex geological structure conditions. The gas disaster is one of the main disasters in my country's coal mines, which poses a serious threat to the safe production of the mine, and the sealing effect of the borehole directly affects the gas drainage effect and the effective drainage radius of the borehole. More than 80% of the air in the system is inhaled through boreholes. If the inhaled air volume of the boreholes is reduced by 1/2 to 1/3, the gas flow rate in the boreholes can be increased by 1.5 to 2 times. Therefore, the sealing effect directly affects the gas extraction effect. During the process of gas drainage drilling and sealing, since there are a large number of cracks in the drilling hole itself after the hole is formed, and the holes (cracks) around the drilling hole are further developed and expanded, the external air under the action of negative pressure in the drainage It is easy to enter the hole from these holes (cracks), which leads to a decrease in the concentration of gas extraction, which directly causes the current situation that the sealing of the coal mine is difficult and the sealing effect is poor. The concentration of gas extracted from coal seam drainage in my country is low, and the negative pressure of extraction is generally low, and the higher the negative pressure, the lower the gas concentration extracted. It can be inferred from this that the current sealing technology is far from achieving the effect of sealing and isolation. For high gassy soft coal seams, the problem of gas leakage in gas drainage boreholes in this coal seam is particularly prominent. In addition, the sealing effect affects the accuracy of coal seam gas pressure measurement. If there is a small amount of gas leakage in the sealing section, the obtained pressure value will be low, resulting in a greater impact on gas occurrence and outburst. Inaccurate judgments, and even make improper prevention and control plans and measures. According to the regulations on the prevention and control of coal and gas outburst, the maximum coal seam gas pressure actually measured on site is one of the four single indicators for coal seam outburst risk identification. The size of coal seam gas pressure reflects the severity of coal seam outburst risk. Efficient sealing of boreholes can accurately measure the gas pressure of the coal seam, which provides an important basis for the mine to formulate outburst prevention measures and compile gas geological maps. At present, most of these tests are carried out on site, and there are relatively few laboratories that can carry out such tests, and the underground is limited by some conditions and various factors, the test results are not satisfactory, and the manpower and material resources are also high. Therefore, there is an urgent need for an experimental system to simulate borehole gas extraction, to study the impact of gas leakage from borehole wall cracks on borehole gas extraction and the sealing performance of sealing materials.

Utility model content

The technical problem to be solved by the utility model is to provide a multi-purpose and multi-purpose borehole gas drainage laboratory simulation system for the above-mentioned deficiencies in the prior art. The experiment that needs to be done on site is moved to the laboratory, the experiment consumes less manpower and material resources, the experiment effect is good, the accuracy of the experiment result is high, the practicability is strong, and it is easy to promote and use.

In order to solve the above technical problems, the technical solution adopted by the utility model is: a multi-purpose multi-purpose borehole gas drainage laboratory simulation system, which is characterized in that it includes a borehole simulation pipe, a sealing grouting system, a gas pressure simulation A loading system, a gas detector, an acoustic emission system and a computer connected to the acoustic emission system; plug simulation structures are arranged at both ends of the drilling simulation pipe, and a section of drilling simulation pipe between the two plug simulation structures A plurality of fissure simulation holes are arranged on the pipe wall, a fissure simulation pipe is connected to the fissure simulation hole, and an air leakage detection switch is connected to the fissure simulation pipe;

The sealing grouting system includes a grouting pipe and a grouting pipe extending into the drilling simulation pipe, and a grouting pump connected to the grouting pipe; the grouting pump is provided with a grouting handle and a grouting pressure gauge ;

The gas pressure simulation loading system includes a vacuum pump connected to one end of the gas extraction pipe through a vacuum pump connecting pipe and a gas tank connected to the other end of the gas extraction pipe through a gas tank connecting pipe, the vacuum pump connecting pipe is connected to a vacuum A pressure gauge and a vacuum switch, the gas gas outlet of the gas tank is provided with a gas tank switch, the connecting pipe of the gas tank is connected with a gas pressure gauge and a gas extraction switch; the grouting pipe is fixed on The lower side of the gas extraction pipe, the slurry return pipe is fixed on the upper side of the gas extraction pipe, and the gas detector is connected to the vacuum pump connecting pipe through the gas detector connecting pipe.

The above-mentioned multi-purpose borehole gas drainage laboratory simulation system is characterized in that: the borehole simulation tube is made of a plexiglass tube with a diameter of 135mm, and the gas drainage tube is controlled by a plexiglass tube with a diameter of 75mm The grouting pipe and the grouting pipe are both made of PVC aluminum-plastic pipes.

The above-mentioned multi-purpose borehole gas drainage laboratory simulation system is characterized in that: the plug simulation structure is composed of cotton gauze wrapped on the gas drainage pipe, grouting pipe and grout return pipe and evenly coated on the cotton gauze The cloth is made of liquid polyurethane foam, and both sides of the plug simulation structure are provided with gaskets for preventing the plug simulation structure from spreading to the left and right.

The above-mentioned multi-purpose borehole gas drainage laboratory simulation system is characterized in that: the gas detector is an optical interference type gas detector.

The above-mentioned multi-purpose borehole gas drainage laboratory simulation system is characterized in that: the acoustic emission system is an SAEU2S acoustic emission system, and the SAEU2S acoustic emission system includes a data acquisition box and a cable connected to the data acquisition box A multi-channel preamplifier, the input end of the preamplifier is connected with a sensor through a signal line, and the data acquisition box is connected with a computer through a USB connection line.

The above-mentioned multi-purpose borehole gas drainage laboratory simulation system is characterized in that: the number of the fissure simulation holes is 6, of which the diameter of the two fissure simulation holes is 2mm, and the aperture of the two fissure simulation holes is The diameter of the other two fissure simulation holes is 4mm; the outer diameter of the fissure simulation tube matches the diameter of the fissure simulation hole.

Compared with the prior art, the utility model has the following advantages:

1. The utility model has the advantages of simple structure, novel and reasonable design, and convenient realization.

2. The utility model is easy to install and easy to operate. Changing the downhole test to the laboratory and directly using the simulation system to replace the downhole drilling gas drainage is equivalent to reducing the downhole site to the laboratory in proportion, reducing the The downhole test time reduces the difficulty of operation, saves the manpower and material resources required for the test, greatly improves the test efficiency and accuracy, and avoids the loss caused by the need to stop production for direct downhole tests.

3. The utility model opens a plurality of fissure simulation holes on the pipe wall of the borehole simulation pipe, and connects the fissure simulation pipe on the fissure simulation hole, and connects the air leakage detection switch on the fissure simulation pipe, so that it can simulate the difference of the borehole wall. The impact of position air leakage on gas drainage eliminates the previous simulation in the laboratory where only the hole wall and material contact air leakage can be simulated, which is very close to the field conditions.

4. The detection means of the utility model are rich and varied, including acoustic emission system and gas detector, etc. Acoustic emission signal data is collected through the acoustic emission system and the collected signal is transmitted to the computer for recording, which can be used for research on acoustic emission signal data When the cement slurry is solidified, the internal stress changes, and then the plugging of the drilled simulated pipe is studied, and whether there is a crack inside the drilled simulated pipe is used; the gas detector can detect the leakage of the cracked simulated hole in different positions and different apertures. Drainage gas concentration is used to analyze the impact of fractures at different positions and diameters on gas drainage from boreholes.

5. The utility model has multiple functions, which can be used to detect the sealing performance of the sealing material, study the influence of air leakage at different positions of the borehole wall on the gas drainage, and perform laboratory simulation of the gas drainage of the borehole; it can not only simulate Borehole gas drainage can also be used to monitor the initiation and expansion of cracks in the sealing section of the borehole by using the acoustic emission system during coal seam gas drainage, which is of great significance to the instability of the sealing section of the borehole.

6. The utility model reduces the influence of many uncertain factors in the downhole test on the test results, and can conduct quantitative research on the factors affecting the test in the laboratory, greatly improving the accuracy of the test results.

7. The utility model can provide a relatively stable gas pressure and concentration inside the borehole, reduce the error of the experiment, and simulate the situation on the spot to the greatest extent.

To sum up, the utility model is novel and reasonable in design, easy to implement, can truly simulate on-site conditions, and move the experiments that need to be done on-site to the laboratory. The experiment consumes less manpower and material resources, and the experiment effect is good and the experimental results are accurate. High performance, strong practicability, easy to popularize and use.

The technical solutions of the present utility model will be further described in detail through the drawings and embodiments below.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Fig. 2 is a diagram of the usage state of the utility model when it is used for drilling gas drainage laboratory simulation.

Fig. 3 is a diagram of the usage status of the utility model when it is used to test the sealing performance of the sealing material.

Explanation of reference signs:

1—fracture simulation hole; 2—vacuum pump; 3—vacuum pressure gauge;

4—vacuum switch; 5—gas drainage pipe; 6—return slurry pipe;

7—drilling simulation tube; 8—plug simulation structure; 9—air leakage detection switch;

10—cement slurry; 11—gas drainage switch; 12—gas tank connection pipe;

13—gas pressure gauge; 14—gas tank switch; 15—gas tank;

16-1—data acquisition chassis; 16-2—preamplifier; 16-3—sensor;

17—crack simulation tube; 18—gasket; 19—vacuum pump connecting pipe;

20—grouting pipe; 21—grouting pressure gauge; 22—grouting handle;

23—grouting pump; 24—gas detector; 25—gas detector connecting pipe;

26—Sealing material.

Detailed ways

As shown in Figure 1, the multi-purpose borehole gas drainage laboratory simulation system of the present invention includes a borehole simulation pipe 7, a hole sealing grouting system, a gas pressure simulation loading system, a gas detector 24, and an acoustic emission system And the computer 17 connected with the acoustic emission system; the two ends of the borehole simulation pipe 7 are provided with a plug simulation structure 8, which is arranged on the pipe wall of a section of the borehole simulation pipe 7 between the two plug simulation structures 8 There are a plurality of crack simulation holes 1, a crack simulation tube 17 is connected to the crack simulation hole 1, and an air leakage detection switch 9 is connected to the crack simulation tube 17;

The sealing grouting system includes a grouting pipe 20 and a grouting pipe 6 extending into the drilling simulation pipe 7, and a grouting pump 23 connected with the grouting pipe 20; Grouting handle 22 and grouting pressure gauge 21;

The gas pressure simulation loading system includes a vacuum pump 2 connected to one end of the gas extraction pipe 5 through a vacuum pump connecting pipe 19 and a gas tank 15 connected to the other end of the gas extraction pipe 5 through a gas tank connecting pipe 12. The vacuum pump A vacuum pressure gauge 3 and a vacuum switch 4 are connected to the connecting pipe 19, a gas gas tank switch 14 is provided on the gas outlet of the gas gas tank 15, and a gas pressure gauge 13 is connected to the connecting pipe 12 of the gas gas tank and gas drainage switch 11; the grouting pipe 20 is fixed on the lower side of the gas drainage pipe 5, the grout return pipe 6 is fixed on the upper side of the gas drainage pipe 5, and the gas detector 24 passes the gas detection Instrument connecting pipe 25 is connected on the vacuum pump connecting pipe 19. During specific implementation, the gas tank connecting pipe 12 is a hose. The gas detector 24 is connected to a section of the vacuum pump connecting pipe 19 between the vacuum pressure gauge 3 and the vacuum switch 4 through the gas detector connecting pipe 25 .

In this embodiment, the drilling simulation pipe 7 is made of a plexiglass pipe with a diameter of 135 mm, the gas drainage pipe 5 is made of a plexiglass pipe with a diameter of 75 mm, the grouting pipe 20 and the grout return pipe 6 All are made of PVC aluminum plastic pipe.

In this embodiment, the plug simulation structure 8 is composed of cotton gauze wrapped on the gas drainage pipe 5, the grouting pipe 20 and the grout return pipe 6, and liquid polyurethane foam evenly applied on the cotton gauze. Both sides of the plug simulation structure 8 are provided with gaskets 18 for preventing the plug simulation structure 8 from spreading to the left and right.

In this embodiment, the gas detector 24 is an optical interference type gas detector.

In this embodiment, the acoustic emission system is an SAEU2S acoustic emission system, and the SAEU2S acoustic emission system includes a data acquisition chassis 16-1 and a multi-channel preamplifier 16-2 connected to the data acquisition chassis 16-1 through a cable, The input end of the preamplifier 16-2 is connected with a sensor 16-3 through a signal line, and the data acquisition box 16-1 is connected with a computer 17 through a USB connection line.

In this embodiment, the number of the fissure simulation holes 1 is 6, wherein the diameter of the two fissure simulation holes 1 is 2 mm, the diameter of the two fissure simulation holes 1 is 3 mm, and the diameter of the other two fissure simulation holes 1 is 3 mm. is 4mm; the outer diameter of the crack simulation tube 17 matches the diameter of the crack simulation hole 1 .

As shown in Figure 2, adopting the utility model to carry out the laboratory simulation method of borehole gas drainage comprises the following steps:

Step 1. Preliminary preparation for the experiment. The specific process is as follows:

Step 101. Take a section of plexiglass pipe with a diameter of 135mm as the drilling simulation pipe 7, take a section of plexiglass pipe with a diameter of 75mm as the gas extraction pipe 5, take a section of PVC aluminum-plastic pipe as the grouting pipe 20, and take a section of PVC The aluminum-plastic pipe is used as the grout return pipe 6; during specific implementation, the diameters of the PVC aluminum-plastic pipes as the grout injection pipe 20 and the grout return pipe 6 are 20mm;

Step 102, opening a plurality of fissure simulation holes 1 on the pipe wall of the drilling simulation pipe 7, connecting the fissure simulation pipe 17 in the fissure simulation hole 1, and connecting the air leakage detection switch 9 on the fissure simulation pipe 17;

Step 103: Bind the gas extraction pipe 5, the grouting pipe 20 and the grout return pipe 6 with iron wires, and fix the grouting pipe 20 on the lower side of the gas extraction pipe 5, and fix the grout return pipe 6 on the gas extraction pipe. The upper side of the tube 5;

Step 104: Cut the cotton gauze into strips, wind them on the gas drainage pipe 5, the grouting pipe 20 and the grout return pipe 6 at the two positions where the plug simulation structure 8 is to be installed, and wrap them on both sides of the cotton gauze. Gaskets 18 for preventing the plugging simulation structure 8 from spreading to the left and right are provided; during specific implementation, the cotton gauze is cut into strips with a width of 6cm to 8cm, and since the plugging simulation structure 8 is made of polyurethane foam, the Gaskets 18 are arranged on both sides of the cotton gauze, which can prevent uneven foaming of the polyurethane, resulting in poor sealing effect or even hole sealing failure;

Step 2. Prefabricate plug simulation structure 8 and form grouting space. The specific process is:

Step 201, after pouring the liquid polyurethane into the beaker, use a brush to dip the liquid polyurethane and apply it evenly on the cotton gauze, and make the liquid polyurethane completely penetrate into the cotton gauze; in actual implementation, since the polyurethane is a chemical material and is poisonous, When performing this step, gloves should be worn to prevent splashing on hands;

Step 202, put the whole gas drainage pipe 5, grouting pipe 20 and grout return pipe 6 coated with liquid polyurethane into the drilling simulation pipe 7, and fix the position so that the gas drainage pipe 5 is located in the gas drainage The middle position in the radial direction of the pipe 5; the gas drainage pipe 5 is located in the middle position in the radial direction of the gas drainage pipe 5, which is conducive to the foaming of liquid polyurethane to form a plug simulation structure 8, which can better plug the borehole. During concrete implementation, because the time of foaming of liquid polyurethane is shorter, so the whole operation process of step 202 should be brief as far as possible, prevents that liquid polyurethane is foamed before being put into drilling simulation tube 7;

Step 203, place the entire drilling simulation pipe 7 fed into the gas extraction pipe 5, grouting pipe 20 and grout return pipe 6 on the test bench, and fix the drilling simulation pipe 7 to avoid drilling The simulation tube 7 slides down, and then stands still for two days, waiting for the liquid polyurethane foam to completely form the plug simulation structure 8;

Step 3: Grouting into the drilling simulation pipe 7, simulating hole sealing, and collecting acoustic emission signal data for studying the sealing of cracks through the acoustic emission system, the specific process is as follows:

Step 301, cleaning the grouting pump 23, and checking the grouting pump 23 to ensure that the grouting pump 23 is intact;

Step 302, after pouring the cement slurry 10 into the grouting pump 23, start the grouting pump 23, first discharge the air in the pipeline of the grouting pump 23, and then connect the grouting pump 23 and the grouting pipe 20;

Step 303, inject the cement slurry 10 through the grouting pipe 20 into the space between the two plug simulation structures 8 in the drilling simulation pipe 7 through the grouting pump 23, and close it until the cement slurry 10 flows out of the grout return pipe 6 Grouting pump 23 stops grouting;

Step 304, lightly tap the drilling simulation pipe 7 with a hammer, so that the cement slurry 10 between the two plug simulation structures 8 is in close contact and the air bubbles therein are discharged;

Step 305, start the grouting pump 23 again for grouting, and close the grouting pump 23 to stop the grouting until the cement slurry 10 flows out in the grout return pipe 6;

Step 306, disconnect the connection between the grouting pump 23 and the grouting pipe 20, and block the grouting port of the grouting pipe 20 and the grouting port of the grouting pipe 6 to prevent the cement slurry 10 from flowing out;

Step 307, cleaning the grouting pump 23 with clean water; this can prevent the cement slurry 10 remaining in the pipeline of the grouting pump 23 from solidifying and blocking the nozzle, affecting the next use;

Step 308, installing multiple sensors 16-3 in the acoustic emission system to different data acquisition positions on the outer wall of the drilling simulation tube 7, and connecting the data acquisition box 16-1 in the acoustic emission system to the computer 17; Let the drilling simulation tube 7 stand still for a week, so that the cement slurry 10 is fully solidified. During the solidification process of the cement slurry 10, the acoustic emission signal data is collected through the acoustic emission system and the collected signal is transmitted to the computer 17 for recording. The signal data is used to study the internal stress change when the cement slurry 10 is solidified, and then to study the plugging of the borehole simulation pipe 7; during specific implementation, the phenomenon of transient elastic waves due to the rapid release of energy from local sources in the material is called acoustic emission. (Acoustic Emission, referred to as AE), sometimes also referred to as stress wave emission; therefore, according to the existing research in the prior art, the internal stress change when the cement slurry 10 is solidified can be studied through the acoustic emission signal data, and then the borehole can be studied. Simulate the plugging situation of the pipe 7, and judge whether there is a crack inside the drill hole simulation pipe 7;

Step 4. Test the negative pressure capability. The specific process is:

Step 401, connect the vacuum pump 2 to one end of the gas extraction pipe 5 through the vacuum pump connecting pipe 19;

Step 402, start the vacuum pump 2, carry out negative pressure detection on the drilling simulation tube 7, observe the reading of the vacuum pressure gauge 3 and record the maximum achievable negative pressure; when the drilling simulation tube 7 reaches the maximum achievable negative pressure, turn off the vacuum pump 2 , and close the vacuum switch 4 that is arranged on the vacuum pump connecting pipe 19; during specific implementation, it is judged that the drilling simulation tube 7 reaches the maximum negative pressure, which is realized by observing the reading of the vacuum pressure gauge 3, when the vacuum pressure gauge 3 When the reading reaches the maximum and does not continue to rise within 1 to 5 minutes, it is judged that the drilling simulation tube 7 has reached the maximum reachable negative pressure;

Step 403: Observe and record the reading of the vacuum pressure gauge 3. When the reading of the vacuum pressure gauge 3 does not change within 10 to 30 minutes, it is judged that the sealing is successful, and step 5 is performed; otherwise, when the reading of the vacuum pressure gauge 3 is within When it drops sharply within 10 to 30 minutes, it is judged that the sealing has failed, repeat steps 1 to 3, and re-simulate grouting and sealing;

During specific implementation, in order to avoid that the internal cracks of the cement slurry 10 affect the test effect of testing the negative pressure ability, before step 4, first visually observe the plugging place of the cement slurry 10 in the drilling simulation pipe 7, whether there are larger cracks or Larger gap; then observe the acoustic emission signal data collected by the acoustic emission system on the computer 17; , to determine whether there are larger cracks or larger voids inside the cement slurry 10 .

Step 5. Detect the influence of air leakage at different positions of the borehole simulation pipe 7 on the gas concentration in the extraction. The specific process is as follows:

Step 501, connect the gas detector 24 to the vacuum pump connecting pipe 19 through the gas detector connecting pipe 25, and connect the gas gas tank 15 to the other end of the gas extraction pipe 5 through the gas gas tank connecting pipe 12;

Step 502, turn on the gas tank switch 14 and the gas extraction switch 11, introduce the gas in the gas tank 15 into the drilling simulation pipe 7 through the gas tank connecting pipe 12, and provide the drilling gas simulated in the laboratory; observe The reading of the gas pressure gauge 13 makes the gas pressure in the drilling simulation pipe 7 be at a constant value;

Step 503, start the vacuum pump 2, perform gas drainage on the borehole simulation pipe 7, turn on the gas leakage detection switches 9 at different positions in turn, and record the readings of the gas detector 24 when the gas leakage detection switches 9 at different positions are turned on . That is to say, the concentration of the extracted gas when the drill hole simulation pipe 7 leaks at different positions is recorded. Since the number of the fissure simulation holes 1 is 6, the apertures of the two fissure simulation holes 1 are 2mm, the apertures of the two fissure simulation holes 1 are 3mm, and the apertures of the other two fissure simulation holes 1 are 4mm; The outer diameter of the fissure simulation pipe 17 matches the aperture of the fissure simulation hole 1; therefore, it is possible to detect the gas concentration in the gas leakage of the fissure simulation holes at different positions and different apertures, and to analyze the gas concentration at different positions and different apertures. The impact of fractures on borehole gas drainage.

In this embodiment, in step 303 and step 305, the grouting pressure is made to be above 1.5 MPa by observing the readings of the grouting pressure gauge 21 . Through the grouting pump 23, the cement slurry 10 is injected into the space between the two plug simulation structures 8 in the drilling simulation pipe 7 under the condition of a pressure of 1.5 MPa or more, so that the cement slurry 10 can be guaranteed to be relatively dense, so that the cement slurry 10 Reduce internal cracks after fully solidified.

As shown in Figure 3, the method for testing the sealing performance of the sealing material using the utility model includes the following steps:

Step 1. Preliminary preparation for the experiment. The specific process is as follows:

Step 101. Take a section of plexiglass pipe with a diameter of 135mm as the drilling simulation pipe 7, take a section of plexiglass pipe with a diameter of 75mm as the gas extraction pipe 5, take a section of PVC aluminum-plastic pipe as the grouting pipe 20, and take a section of PVC The aluminum-plastic pipe is used as the grout return pipe 6; during specific implementation, the diameters of the PVC aluminum-plastic pipes as the grout injection pipe 20 and the grout return pipe 6 are 20mm;

Step 102: Drill 6 fissure simulation holes 1 on the pipe wall of the drilling simulation pipe 7, of which 2 fissure simulation holes 1 have an aperture diameter of 2mm, of which 2 fissure simulation holes 1 have an aperture diameter of 3mm, and the other 2 fissure simulation holes 1 have a diameter of 3mm. The diameter of the simulated hole 1 is 4mm;

Step 103: Bind the gas extraction pipe 5, the grouting pipe 20 and the grout return pipe 6 with iron wires, and fix the grouting pipe 20 on the lower side of the gas extraction pipe 5, and fix the grout return pipe 6 on the gas extraction pipe. The upper side of the tube 5;

Step 104: Cut the cotton gauze into strips, wind them on the gas drainage pipe 5, the grouting pipe 20 and the grout return pipe 6 at the two positions where the plug simulation structure 8 is to be installed, and wrap them on both sides of the cotton gauze. Gaskets 18 for preventing the plugging simulation structure 8 from spreading to the left and right are provided; during specific implementation, the cotton gauze is cut into strips with a width of 6cm to 8cm, and since the plugging simulation structure 8 is made of polyurethane foam, the Gaskets 18 are arranged on both sides of the cotton gauze, which can prevent uneven foaming of the polyurethane, resulting in poor sealing effect or even hole sealing failure;

Step 2. Prefabricate plug simulation structure 8 and form grouting space. The specific process is:

Step 201, after pouring the liquid polyurethane into the beaker, use a brush to dip the liquid polyurethane and apply it evenly on the cotton gauze, and make the liquid polyurethane completely penetrate into the cotton gauze; in actual implementation, since the polyurethane is a chemical material and is poisonous, When performing this step, gloves should be worn to prevent splashing on hands;

Step 202, put the whole gas drainage pipe 5, grouting pipe 20 and grout return pipe 6 coated with liquid polyurethane into the drilling simulation pipe 7, and fix the position so that the gas drainage pipe 5 is located in the gas drainage The middle position in the radial direction of the pipe 5; the gas drainage pipe 5 is located in the middle position in the radial direction of the gas drainage pipe 5, which is conducive to the foaming of liquid polyurethane to form a plug simulation structure 8, which can better plug the borehole. During concrete implementation, because the time of foaming of liquid polyurethane is shorter, so the whole operation process of step 202 should be brief as far as possible, prevents that liquid polyurethane is foamed before being put into drilling simulation tube 7;

Step 203, place the entire drilling simulation pipe 7 fed into the gas extraction pipe 5, grouting pipe 20 and grout return pipe 6 on the test bench, and fix the drilling simulation pipe 7 to avoid drilling The simulation tube 7 slides down, and then stands still for two days, waiting for the liquid polyurethane foam to completely form the plug simulation structure 8;

Step 3: Inject the sealing material 26 into the drilling simulation pipe 7, and observe the sealing of the fissures. The specific process is as follows:

Step 301, cleaning the grouting pump 23, and checking the grouting pump 23 to ensure that the grouting pump 23 is intact;

Step 302, after pouring the sealing material 26 into the grouting pump 23, start the grouting pump 23, first discharge the air in the pipeline of the grouting pump 23, and then connect the grouting pump 23 and the grouting pipe 20;

Step 303, use the grouting pump 23 to inject the sealing material 26 into the space between the two plug simulation structures 8 in the drilling simulation pipe 7 through the grouting pipe 20, and observe and record that the sealing material 26 has a hole diameter of 2 mm and a diameter of 2 mm. 3mm and 4mm aperture are the plugging situation of the fissure simulation hole 1; and the drilling simulation pipe 7 is set horizontally and inclined to simulate inclined drilling and horizontal drilling, and when the drilling simulation pipe 7 is horizontal and inclined, the sealing The plugging situation of the hole material 26 for the fissure simulation hole 1 with a hole diameter of 2 mm, a hole diameter of 3 mm and a hole diameter of 4 mm; the plugging time reaches the specified grouting pressure from the indication of the grouting pressure gauge 21 and the crack simulation hole 1 starts to leak Timing, until the fissure simulation hole 1 is completely blocked, that is, no liquid leakage ends, take the average value of the plugging time of the fissure simulation hole 1 with the same pore diameter under the same experimental conditions; in specific implementation, the designated grouting pressure is above 1.5MPa ;

Step 304, cleaning the grouting pump 23 with clean water; this can prevent the sealing material 26 remaining in the pipeline of the grouting pump 23 from solidifying and blocking the nozzle, affecting the next use;

Step 4. Test the negative pressure capability. The specific process is:

Step 401, connect the vacuum pump 2 to one end of the gas extraction pipe 5 through the vacuum pump connecting pipe 19;

Step 402, start the vacuum pump 2, carry out negative pressure detection on the drilling simulation tube 7, observe the reading of the vacuum pressure gauge 3 and record the maximum achievable negative pressure; when the drilling simulation tube 7 reaches the maximum achievable negative pressure, turn off the vacuum pump 2 , and close the vacuum switch 4 arranged on the vacuum pump connecting pipe 19, observe the reading of the vacuum pressure gauge 3 and record it. During specific implementation, it is judged that the drilling simulation tube 7 reaches the maximum negative pressure, which is realized by observing the reading of the vacuum pressure gauge 3. When the reading of the vacuum pressure gauge 3 reaches the maximum and does not continue to rise within 1 to 5 minutes , it is judged that the drilling simulation tube 7 has reached the maximum achievable negative pressure.

During specific implementation, in order to carry out comparative experiments, in step 102, two rows of fissure simulation holes 1 corresponding in size and position may be opened, and a row of fissure simulation holes 1 shall be sealed with a solid sealant during the first experiment. When doing the next comparison test, use a needle to poke open a row of fissure simulation holes 1 after plugging, and at the same time seal another row of fissure simulation holes 1 with solid sealant, and rotate the drilling simulation pipe 7 to make the fissures The simulation hole 1 is located at the top of the drilling simulation pipe 7 .

In this embodiment, the sealing material 26 is polyurethane, common cement, expansive cement or PD material.

The above are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any simple modifications, changes and equivalent structural changes made to the above embodiments according to the technical essence of the present utility model still belong to Within the scope of protection of the technical solution of the utility model.

Claims (6)

1. A multi-purpose borehole gas drainage laboratory simulation system is characterized in that: it comprises a borehole simulation pipe (7), a sealing grouting system, a gas pressure simulation loading system and a gas detector (24), and an acoustic Emitting system and computer (17) connected with the acoustic emission system; two ends of the borehole simulation tube (7) are provided with a plug simulation structure (8), located in a section between the two plug simulation structures (8) The pipe wall of the drilling simulation pipe (7) is provided with a plurality of fissure simulation holes (1), the fissure simulation holes (1) are connected with fissure simulation pipes (17), and the fissure simulation pipes (17) are connected with There is an air leakage detection switch (9); The sealing grouting system includes a grouting pipe (20) and a grouting pipe (6) extending into the drilling simulation pipe (7), and a grouting pump (23) connected to the grouting pipe (20); The grouting pump (23) is provided with a grouting handle (22) and a grouting pressure gauge (21); The gas pressure simulation loading system includes a vacuum pump (2) connected to one end of the gas extraction pipe (5) through a vacuum pump connection pipe (19) and a vacuum pump (2) connected to the other end of the gas extraction pipe (5) through a gas tank connection pipe (12). The gas tank (15) at one end, the vacuum pump connecting pipe (19) is connected with a vacuum pressure gauge (3) and a vacuum switch (4), the gas outlet of the gas tank (15) is provided with a gas Gas tank switch (14), the gas pressure gauge (13) and gas extraction switch (11) are connected on the gas gas tank connecting pipe (12); the grouting pipe (20) is fixed on the gas extraction pipe ( 5), the slurry return pipe (6) is fixed on the upper side of the gas extraction pipe (5), and the gas detector (24) is connected to the vacuum pump connecting pipe ( 19) On. 2. according to claim 1, a kind of multipurpose borehole gas drainage laboratory simulation system is characterized in that: the borehole simulation pipe (7) is made of a plexiglass tube with a diameter of 135mm, and the gas pumping The extraction pipe (5) is made of a plexiglass pipe with a diameter of 75mm, and the grouting pipe (20) and the grout return pipe (6) are all made of a PVC aluminum-plastic pipe. 3. according to a kind of multi-purpose borehole gas drainage laboratory simulation system according to claim 1, it is characterized in that: the plug simulation structure (8) consists of gas drainage pipe (5), grouting pipe (20) and the cotton gauze on the size return pipe (6) and the liquid polyurethane foam evenly spread on the cotton gauze constitute, both sides of the plug simulation structure (8) are provided with a simulation structure for preventing the plug ( 8) Spacers (18) that diffuse to the left and right. 4. A multipurpose borehole gas extraction laboratory simulation system according to claim 1, characterized in that: said gas detector (24) is an optical interference type gas detector. 5. according to a kind of multipurpose borehole gas drainage laboratory simulation system according to claim 1, it is characterized in that: described acoustic emission system is SAEU2S acoustic emission system, and described SAEU2S acoustic emission system comprises data acquisition cabinet (16 -1) and a multi-channel preamplifier (16-2) connected to the data acquisition chassis (16-1) through a cable, the input end of the preamplifier (16-2) is connected with a sensor (16-2) by a signal line 3), the data acquisition case (16-1) is connected to the computer (17) through a USB cable. 6. A multi-purpose borehole gas drainage laboratory simulation system according to claim 1, characterized in that: the number of said fissure simulation holes (1) is 6, of which 2 are fissure simulation holes (1) The diameter of the aperture is 2mm, wherein the aperture of the 2 crack simulation holes (1) is 3mm, and the aperture of the other 2 crack simulation holes (1) is 4mm; the outer diameter of the crack simulation pipe (17) is the same as the crack simulation hole (1 ) to match the hole diameter.