Experimental device and method for multi-angle drilling and sealing effect under gas outflow conditions

Abstract

The present invention discloses an experimental device for the sealing effect of multi-angle drilling under gas gushing conditions, comprising a high-pressure gas cylinder, a gas gushing pipe network, a drilling simulation pipe, a support leg and a grouting system. The gas gushing pipe network comprises a main line and a gas branch pipe. A plurality of gas branch pipes are connected to one end of the main line. The end of the gas branch pipe is equipped with an outlet sleeve. The plurality of outlet sleeves are sleeved on the surface of the drilling simulation pipe. The drilling simulation pipe is assembled at the upper end of the support leg. The grouting system is assembled in the drilling simulation pipe. Also disclosed is an experimental method for the sealing effect of multi-angle drilling under gas gushing conditions. The present invention designs the entire experimental device to facilitate the selection of drilling and grouting methods with different spatial forms, can effectively simulate actual sealing experiments, is simple to operate, and has obvious results. It can effectively observe the gas occurrence conditions of different coal seams, the flow law and bonding strength of sealing materials in boreholes with different spatial forms, and provide theoretical support for the grouting and sealing work of actual coal seam drilling.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mine safety, and in particular provides a device and method for experimentally testing multi-angle drilling and sealing effects under gas outflow conditions. Background Art

[0002] Coal seam gas extraction is an important technical measure for preventing and controlling coal mine gas disasters. Currently, the sealing effect of coal seam gas drilling is poor, and the gas extraction concentration is low. Since the gas contained in the coal seam itself continuously flows into the borehole during the sealing process, it is more difficult to seal the coal seam section drilling. The current means of investigating the sealing effect usually adopts the statistical method of gas concentration in the extraction borehole. Due to the limitations of underground coal mine conditions, there is a lack of effective technical means to observe the flow and bonding strength of sealing materials in different coal seam gas conditions and boreholes of different shapes. There are few experimental devices and technical studies that simulate the flow and bonding process of sealing materials in underground gas-containing coal seam drilling in the laboratory. Summary of the Invention

[0003] In order to solve the above problems, the present invention provides an experimental device and method for multi-angle drilling and sealing effects under gas outflow conditions.

[0004] To achieve the above-mentioned purpose, the technical solution adopted in the present invention is: an experimental device for the effect of multi-angle drilling and sealing under gas outflow conditions, including a high-pressure gas cylinder, a gas outflow pipe network, a drilling simulation pipe, a support leg and a grouting system, the gas outflow pipe network includes a main line and a gas branch pipe, multiple gas branch pipes are connected to one end of the main line, the end of the gas branch pipe is equipped with an outlet sleeve, multiple outlet sleeves are sleeved on the surface of the drilling simulation pipe, the surface of the drilling simulation pipe is provided with a sieve hole located on the inner side of the outlet sleeve, the other end of the main line is connected to the high-pressure gas cylinder, the drilling simulation pipe is assembled on the upper end of the support leg, the support leg can be raised and lowered, and the grouting system is assembled in the drilling simulation pipe.

[0005] Furthermore, the main pipe is equipped with a gas cylinder pressure gauge and a gas cylinder valve, and the gas branch pipe is equipped with a branch pipe valve and a branch pipe pressure gauge.

[0006] Furthermore, the diameter of the drilling simulation tube is 65 mm to 130 mm, one end of the drilling simulation tube is open and a flange is fixedly installed at the other end.

[0007] Furthermore, the support leg includes a stabilizing plate, an adjusting bolt, an adjusting tube, a movable connecting buckle and a drilling tube fixing sleeve, the adjusting bolt is fixedly mounted on the stabilizing plate, and the adjusting bolt is threaded into the adjusting tube, the movable connecting buckle is rotatably assembled on the upper end of the adjusting tube, the drilling tube fixing sleeve is fixedly mounted on the movable connecting buckle, and the drilling simulation tube is assembled in the drilling tube fixing sleeve.

[0008] Furthermore, the grouting system includes a grouting pump and a grouting sealer, and the output end of the grouting pump is equipped with a grouting pressure gauge and a grouting hose.

[0009] Furthermore, the grouting sealer includes a front-end sealing capsule, a rear-end sealing capsule, an exhaust pipe and a grouting pipe. The front-end sealing capsule and the rear-end sealing capsule are assembled in the drilling simulation pipe. The front-end sealing capsule is close to the opening of the drilling simulation pipe, and the rear-end sealing capsule is located inside the drilling simulation pipe. The space between the front-end sealing capsule and the rear-end sealing capsule in the drilling simulation pipe is the grouting space. The exhaust pipe and the grouting pipe both pass through the front-end sealing capsule. The inner end of the exhaust pipe is located in the grouting space, and the outer end of the exhaust pipe is located outside the opening. The outer end of the exhaust pipe is equipped with an exhaust pipe valve. The inner end of the grouting pipe is located in the rear-end sealing capsule, and the outer end of the grouting pipe is connected to the grouting hose. The outer end of the grouting pipe is equipped with a grouting pipe valve. The grouting pipe is equipped with a grouting pipe bursting valve, and the grouting pipe bursting valve is located in the grouting space.

[0010] The grouting pipe is equipped with a one-way valve, and there are two one-way valves in total. The two one-way valves are respectively located in the front end sealing capsule and the rear end sealing capsule.

[0011] The experimental method for the effect of multi-angle drilling and sealing under gas gushing conditions utilizes the above-mentioned experimental device for the effect of multi-angle drilling and sealing under gas gushing conditions, and specifically includes the following steps:

[0012] S1, connect the high-pressure gas cylinder, the gas cylinder pressure gauge, the gas cylinder valve, and the gas outflow pipe network in sequence, and install the branch pipe valve and branch pipe pressure gauge on each gas branch pipe of the gas outflow pipe network in sequence;

[0013] S2, a drilling simulation tube with one end open and the other end closed with a flange, serving as the bottom of the simulated hole. A group of sieve holes are arranged at regular intervals on the drilling simulation tube. Gas outlet casings are sleeved on the drilling simulation tube. Multiple gas outlet casings are placed at the sieve holes, and the gas branch pipes are connected to the gas outlet casings.

[0014] S3. Install several support legs for fixing and adjusting the drilling simulation tube. The installation order of a single support leg is to install the stabilizing plate, adjusting bolt, adjusting tube, movable connecting buckle and drilling tube fixing sleeve from bottom to top, and fix the drilling simulation tube through the drilling tube fixing sleeve.

[0015] S4, connecting the rear end sealing capsule and the front end sealing capsule to the grouting pipe, and sequentially inserting the rear end sealing capsule, the grouting pipe bursting valve and the front end sealing capsule into the drilling simulation pipe, installing an exhaust pipe on the front end sealing capsule, installing an exhaust pipe valve on the exhaust pipe, and installing a grouting pipe valve on the grouting pipe;

[0016] S5, install a grouting pressure gauge and a grouting hose on the grouting pump, and connect the grouting hose and the grouting pipe;

[0017] S6, adjust the height of the support legs by adjusting the bolts and adjusting the tubes, and then adjust the spatial layout and angle of the drilling simulation tubes to obtain the following spatial forms of drilling:

[0018] 1. Nearly horizontal drilling with a drilling inclination of -5° to 5°;

[0019] 2. Drilling holes with an inclination angle greater than 5° and monotonously ascending;

[0020] 3. Drill holes with an inclination angle of less than -5° and monotonously descending;

[0021] 4. The drilling trajectory presents a concave drilling;

[0022] 5. The drilling trajectory presents a convex drilling;

[0023] Simulate the spatial form of one of the boreholes;

[0024] S7, opening the gas cylinder valve to allow the high-pressure gas in the high-pressure gas cylinder to enter the gas outflow pipe network, and at the same time controlling the branch pipe valve on each gas branch pipe so that the value of each branch pipe pressure gauge reaches the designed value, and the gas enters the borehole simulation pipe through the gas outlet casing and the sieve hole, simulating the flow of coal seam gas in the borehole;

[0025] S8, turning on the grouting pump, adjusting the grouting pressure according to the data displayed on the grouting pressure gauge so that the grouting pressure meets the experimental design requirements, opening the grouting pipe valve, opening the exhaust pipe valve, and allowing the slurry to enter the front-end sealing capsule and the rear-end sealing capsule through the grouting pipe. When the grouting pressure reaches the critical value of the grouting pipe bursting valve, the grouting pipe bursting valve ruptures, and the slurry enters the grouting space between the front-end sealing capsule and the rear-end sealing capsule;

[0026] S9, during the process of continuous injection of slurry into the grouting space, the gas entering from the gas outlet casing and the sieve holes continuously surges out to disturb the slurry, and at the same time, the gas is discharged from the exhaust pipe valve. When slurry flows out of the exhaust pipe valve, it means that most of the gas in the grouting space has been discharged. The exhaust pipe valve is closed and high-pressure grouting is continued;

[0027] The slurry flow pattern was observed during the grouting process, and the slurry was taken out and measured after solidification to obtain the bonding strength;

[0028] S10, repeating steps S6 to S9, simulating different borehole spatial forms, implementing slurry coagulation experiments under different borehole spatial forms, and obtaining slurry flow patterns and bonding strengths under different borehole spatial forms.

[0029] Furthermore, in step S8, the number of front-end sealing capsules or rear-end sealing capsules is increased or decreased, the length of the exhaust pipe and the grouting pipe is adjusted, and the installation position of the grouting pipe burst valve is changed to achieve different grouting methods.

[0030] Furthermore, in step S9, during the grouting process, the branch pipe valve is controlled to adjust the pressure and flow of the injected gas, the grouting pipe valve is adjusted to change the grouting pressure, the exhaust pipe valve is opened and closed in stages multiple times, and the gas and clean water in the slurry are discharged, thereby realizing a slurry coagulation experiment under the influence of multiple parameter environments in the spatial form of a borehole.

[0031] The beneficial effects of using the present invention are:

[0032] The present invention designs a high-pressure gas cylinder and a gas outflow pipe network to simulate the outflow of gas in coal seam drilling holes, designs a drilling simulation pipe and a support leg to simulate drilling holes of different spatial forms, and is equipped with a grouting system to form an entire experimental device. During the experiment, it is convenient to select drilling holes and grouting methods of different spatial forms, which can effectively simulate the actual sealing experiment and obtain the slurry flow law and the bonding strength of the slurry after solidification. The experimental operation is simple and the experimental results are obvious. It can effectively observe the gas occurrence conditions of different coal seams, the flow law and bonding strength of the sealing materials in drilling holes of different spatial forms, and provide theoretical support for the grouting and sealing work of actual coal seam drilling. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the structure of the experimental device for multi-angle drilling and sealing effects under gas outflow conditions of the present invention.

[0034] Figure 2 This is a schematic diagram of the arrangement of the drilling simulation tube and support legs for simulating upward drilling in the present invention.

[0035] Figure 3 This is a schematic diagram of the arrangement of the drilling simulation tube and support legs for simulating downhole drilling in the present invention.

[0036] Figure 4 This is a schematic diagram of the arrangement of the drilling simulation tube and support legs for simulating concave drilling according to the present invention.

[0037] Figure 5 This is a schematic diagram of the arrangement of the drilling simulation tube and support legs for simulating convex drilling according to the present invention.

[0038] The accompanying drawings include: 1. high-pressure gas cylinder, 2. gas cylinder pressure gauge, 3. gas cylinder valve, 4. gas outflow pipe network, 401. gas branch pipe, 4011. branch pipe valve, 4012. branch pipe pressure gauge, 4013. gas outlet casing, 5. drilling simulation pipe, 501. flange, 502. sieve hole, 6. support leg, 601. stabilizing plate, 602. adjusting bolt, 603. adjusting pipe, 604. movable connecting buckle, 605. drilling pipe fixing sleeve, 7. grouting pump, 701. grouting pressure gauge, 702. grouting hose, 8. grouting sealer, 801. front-end sealing capsule, 802. rear-end sealing capsule, 803. exhaust pipe, 8031. exhaust pipe valve, 804. grouting pipe, 8041. grouting pipe valve, 8042. grouting pipe bursting valve. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] Example 1

[0041] Reference Figure 1 The experimental device for multi-angle drilling and sealing effects under gas outflow conditions includes a high-pressure gas cylinder 1, a gas outflow pipe network 4, a drilling simulation pipe 5, a support leg 6 and a grouting system. The gas outflow pipe network 4 includes a main line and a gas branch pipe 401. Multiple gas branch pipes 401 are connected to one end of the main line. The end of the gas branch pipe 401 is equipped with an outlet sleeve 4013. Multiple outlet sleeves 4013 are sleeved on the surface of the drilling simulation pipe 5. The surface of the drilling simulation pipe 5 is provided with a sieve hole 502 located on the inner side of the outlet sleeve 4013. The other end of the main line is connected to the high-pressure gas cylinder 1. The drilling simulation pipe 5 is assembled on the upper end of the support leg 6. The support leg 6 can be raised and lowered. The grouting system is assembled in the drilling simulation pipe 5.

[0042] The high-pressure gas cylinder 1 is used to provide high-pressure gas, and the gas source is methane, carbon dioxide or nitrogen.

[0043] The gas outflow pipe network 4 is used to simulate the path of gas outflow into the borehole in the coal seam. The number of gas branches 401 can be adjusted according to experimental needs. This embodiment is illustrated with three gas branches 401. The gas branches 401 supply gas to the drilling simulation pipe 5 through the gas outlet casing 4013 and the sieve hole 502.

[0044] By adjusting the number and position of the gas branch pipes 401 , different coal seam gas occurrence conditions can be simulated.

[0045] The drilling simulation tube 5 is made of a transparent material resistant to high pressure and has a bendable property and is used to simulate coal seam drilling.

[0046] The support legs 6 are used to fix and adjust the drilling simulation tube 5. In actual applications, multiple groups of support legs 6 will be used to support the drilling simulation tube 5.

[0047] The grouting system is used to inject slurry into the drilled simulation pipe 5 to complete functions such as injection, plugging, and exhaust.

[0048] Specifically, the main pipe is equipped with a gas cylinder pressure gauge 2 and a gas cylinder valve 3, and the gas branch pipe 401 is equipped with a branch pipe valve 4011 and a branch pipe pressure gauge 4012.

[0049] The gas cylinder pressure gauge 2 measures the output gas pressure of the high-pressure gas cylinder 1, and the gas pressure can be adjusted through the gas cylinder valve 3.

[0050] The branch pipe pressure gauge 4012 is used to measure the air pressure in the gas branch pipe 401 , and the air pressure can be adjusted through the branch pipe valve 4011 .

[0051] Specifically, the diameter of the drilling simulation tube 5 is 65 mm to 130 mm, one end of the drilling simulation tube 5 is open and a flange 501 is fixedly installed at the other end.

[0052] The diameter of the drilling simulation tube 5 can be selected from 75mm, 93mm, 98mm, 113mm, 130mm, etc.

[0053] The opening of the drilling simulation tube 5 simulates the coal seam drilling hole mouth, and the flange 501 simulates the coal seam drilling hole bottom.

[0054] Specifically, the support leg 6 includes a stabilizing plate 601, an adjusting bolt 602, an adjusting tube 603, a movable connecting buckle 604 and a drilling tube fixing sleeve 605. The adjusting bolt 602 is fixedly installed on the stabilizing plate 601, and the adjusting bolt 602 is screwed into the adjusting tube 603. The movable connecting buckle 604 is rotatably assembled on the upper end of the adjusting tube 603. The drilling tube fixing sleeve 605 is fixedly installed on the movable connecting buckle 604, and the drilling simulation tube 5 is assembled in the drilling tube fixing sleeve 605.

[0055] The connection relationship between the movable connecting buckle 604 and the adjusting tube 603 is a rotational assembly, and a hole-shaft installation can be adopted so that when the adjusting tube 603 rotates, the movable connecting buckle 604 will not rotate therewith.

[0056] By rotating the adjusting tube 603, it can be raised and lowered on the adjusting bolt 602 through the threaded relationship. By adjusting the heights of multiple sets of support legs 6 to different degrees, the inclination angle and bending degree of the drilling simulation tube 5 can be adjusted, so that the drilling simulation tube 5 can simulate nearly horizontal drilling, upward drilling, downward drilling, concave drilling and convex drilling.

[0057] Figure 1 The drilling simulation tube 5 in the figure simulates a nearly horizontal drilling. Figure 2 The drilling simulation tube 5 in the middle simulates the upward drilling. Figure 3 The drilling simulation tube 5 in the figure simulates the down-going drilling. Figure 4 The drilling simulation tube 5 simulates a concave drilling. Figure 5 The drilling simulation tube 5 simulates a convex drilling.

[0058] The adjusting bolt 602 and the adjusting tube 603 have different length specifications. Different specifications are selected according to actual use needs to ensure that the drilling simulation tube 5 can form different inclination angles or bends.

[0059] Specifically, the grouting system includes a grouting pump 7 and a grouting sealer 8. The output end of the grouting pump 7 is equipped with a grouting pressure gauge 701 and a grouting hose 702.

[0060] The grouting pump 7 is used to provide drilling sealing material slurry into the drilling simulation pipe 5. The slurry can be a single liquid or a double liquid. The first and second embodiments are described with a single liquid.

[0061] The grouting pressure gauge 701 is used to measure the grouting pressure of the grouting pump 7, and then the grouting pump 7 can be adjusted to make the grouting pressure meet the experimental design requirements.

[0062] Specifically, the grouting sealer 8 includes a front-end sealing capsule 801, a rear-end sealing capsule 802, an exhaust pipe 803 and a grouting pipe 804. The front-end sealing capsule 801 and the rear-end sealing capsule 802 are assembled in the drilling simulation pipe 5. The front-end sealing capsule 801 is close to the opening of the drilling simulation pipe 5, and the rear-end sealing capsule 802 is located inside the drilling simulation pipe 5. The space between the front-end sealing capsule 801 and the rear-end sealing capsule 802 in the drilling simulation pipe 5 is the grouting space. The exhaust pipe 803 and the grouting pipe 804 are both The exhaust pipe 803 passes through the front end sealing capsule 801, the inner end of the exhaust pipe 803 is located in the grouting space, and the outer end of the exhaust pipe 803 is located outside the opening, the outer end of the exhaust pipe 803 is equipped with an exhaust pipe valve 8031, the inner end of the grouting pipe 804 is located in the rear end sealing capsule 802, and the outer end of the grouting pipe 804 is connected to the grouting hose 702, the outer end of the grouting pipe 804 is equipped with a grouting pipe valve 8041, the grouting pipe 804 is equipped with a grouting pipe bursting valve 8042, and the grouting pipe bursting valve 8042 is located in the grouting space.

[0063] The grouting sealer 8 is used to realize the functions of slurry injection, sealing, and exhaust in the drilling simulation pipe 5.

[0064] The front-end sealing capsule 801 and the rear-end sealing capsule 802 are used to seal the slurry and confine the slurry in the grouting space between the front-end sealing capsule 801 and the rear-end sealing capsule 802 .

[0065] The exhaust pipe 803 and the exhaust pipe valve 8031 ​​are used to discharge the gas in the grouting space during the grouting process.

[0066] When performing grouting, the slurry is first injected into the front sealing capsule 801 and the rear sealing capsule 802 to seal both ends of the drilling simulation tube 5. Then, as the slurry pressure in the grouting tube 804 increases, the grouting tube burst valve 8042 will rupture, and the slurry will enter the grouting space to complete the sealing work.

[0067] Specifically, the grouting pipe 804 is equipped with two one-way valves, which are respectively located in the front sealing capsule 801 and the rear sealing capsule 802.

[0068] The one-way valve allows the slurry to flow only from the grouting pipe 804 into the front end sealing capsule 801 and the rear end sealing capsule 802 , preventing the slurry in the front end sealing capsule 801 and the rear end sealing capsule 802 from flowing back into the grouting pipe 804 .

[0069] Example 2

[0070] The experimental method for the multi-angle drilling and sealing effect under gas gushing conditions uses the multi-angle drilling and sealing effect experimental device under gas gushing conditions as described in Example 1, specifically comprising the following steps:

[0071] S1, connect the high-pressure gas cylinder 1, the gas cylinder pressure gauge 2, the gas cylinder valve 3, and the gas outflow pipe network 4 in sequence, and install the branch pipe valve 4011 and the branch pipe pressure gauge 4012 on each gas branch pipe 401 of the gas outflow pipe network 4 in sequence;

[0072] S2: One end of the simulated borehole tube 5 is open, and the other end is sealed with a flange 501, serving as the simulated hole bottom. A set of sieve holes 502 are arranged at regular intervals on the simulated borehole tube 5. A gas outlet sleeve 4013 is sleeved onto the simulated borehole tube 5. Multiple gas outlet sleeves 4013 are placed at the sieve holes 502, and the gas branch pipe 401 is connected to the gas outlet sleeve 4013.

[0073] A sealing structure is provided between the air outlet casing 4013 and the drilling simulation tube 5;

[0074] S3, install several support legs 6 for fixing and adjusting the drilling simulation tube 5. The installation order of a single support leg 6 is to install the stabilizing plate 601, the adjusting bolt 602, the adjusting tube 603, the movable connecting buckle 604 and the drilling tube fixing sleeve 605 from bottom to top, and fix the drilling simulation tube 5 through the drilling tube fixing sleeve 605;

[0075] S4, connect the rear end sealing capsule 802 and the front end sealing capsule 801 to the grouting pipe 804, and sequentially send the rear end sealing capsule 802, the grouting pipe bursting valve 8042 and the front end sealing capsule 801 into the drilling simulation pipe 5, install the exhaust pipe 803 on the front end sealing capsule 801, install the exhaust pipe valve 8031 ​​on the exhaust pipe 803, and install the grouting pipe valve 8041 on the grouting pipe 804;

[0076] S5, install the grouting pressure gauge 701 and the grouting hose 702 on the grouting pump 7, and connect the grouting hose 702 and the grouting pipe 804;

[0077] S6, adjusting the height of the support leg 6 by adjusting the bolt 602 and the adjusting tube 603, thereby adjusting the spatial arrangement position and angle of the drilling simulation tube 5 to obtain the following spatial shapes of the drilling:

[0078] 1. Nearly horizontal drilling with a drilling inclination of -5° to 5°;

[0079] 2. Drilling holes with an inclination angle greater than 5° and monotonously ascending;

[0080] 3. Drill holes with an inclination angle of less than -5° and monotonously descending;

[0081] 4. The drilling trajectory presents a concave drilling;

[0082] 5. The drilling trajectory presents a convex drilling;

[0083] Simulate the spatial form of one of the boreholes;

[0084] S7: Open the gas cylinder valve 3 to allow the high-pressure gas in the high-pressure gas cylinder 1 to enter the gas outflow pipe network 4. Simultaneously, control the branch pipe valve 4011 on each gas branch pipe 401 so that the value of each branch pipe pressure gauge 4012 reaches the designed value. The gas then flows through the gas outlet casing 4013 and the sieve hole 502 into the borehole simulation pipe 5, simulating the flow of coalbed methane in the borehole.

[0085] S8, turn on the grouting pump 7, adjust the grouting pressure according to the data displayed on the grouting pressure gauge 701, so that the grouting pressure meets the experimental design requirements, open the grouting pipe valve 8041, open the exhaust pipe valve 8031, and the slurry enters the front sealing capsule 801 and the rear sealing capsule 802 through the grouting pipe 804. When the grouting pressure reaches the critical value of the grouting pipe bursting valve 8042, the grouting pipe bursting valve 8042 ruptures, and the slurry enters the grouting space between the front sealing capsule 801 and the rear sealing capsule 802;

[0086] Increase or decrease the number of front-end sealing capsules 801 or rear-end sealing capsules 802, adjust the length of the exhaust pipe 803 and the grouting pipe 804, and change the installation position of the grouting pipe burst valve 8042 to achieve different grouting methods;

[0087] Different grouting methods include two-blocking and one-shot, three-blocking and two-shot sealing methods, among which the hole grouting or hole bottom grouting can be used, and the hole venting or hole bottom venting can be used;

[0088] S9, during the process of continuous injection of slurry into the grouting space, the gas entering from the gas outlet sleeve 4013 and the sieve hole 502 continuously surges out to disturb the slurry, and at the same time, the gas is discharged from the exhaust pipe valve 8031. When slurry flows out of the exhaust pipe valve 8031, it means that most of the gas in the grouting space has been discharged. The exhaust pipe valve 8031 ​​is closed and the high-pressure grouting is continued;

[0089] The slurry flow pattern was observed during the grouting process, and the slurry was taken out and measured after solidification to obtain the bonding strength;

[0090] During the grouting process, the branch pipe valve 4011 is controlled to adjust the pressure and flow of the injected gas, the grouting pipe valve 8041 is adjusted to change the grouting pressure, and the exhaust pipe valve 8031 ​​is opened and closed in stages multiple times to discharge the gas and clean water in the slurry. This allows for a slurry coagulation experiment under the influence of multiple parameter environments in a borehole's spatial form, thereby obtaining the slurry flow pattern and bonding strength under the influence of different parameter environments.

[0091] S10, repeating steps S6 to S9, simulating different borehole spatial forms, implementing slurry coagulation experiments under different borehole spatial forms, and obtaining slurry flow patterns and bonding strengths under different borehole spatial forms.

[0092] The above content is only a preferred embodiment of the present invention. For ordinary technicians in this field, according to the concept of the present invention, many changes can be made in the specific implementation method and application scope. As long as these changes do not deviate from the concept of the present invention, they all fall within the scope of protection of the present invention.

Claims

1. An experimental method for the sealing effect of multi-angle drilling under gas gushing conditions, using an experimental device for the sealing effect of multi-angle drilling under gas gushing conditions, the device comprising a high-pressure gas cylinder, a gas gushing pipe network, a drilling simulation pipe, a support leg and a grouting system, wherein the gas gushing pipe network comprises a main line and a gas branch pipe, a plurality of the gas branch pipes being connected to one end of the main line, the ends of the gas branch pipes being equipped with gas outlet sleeves, the plurality of gas outlet sleeves being sleeved on the surface of the drilling simulation pipe, the surface of the drilling simulation pipe being provided with sieve holes located on the inner side of the gas outlet sleeves, the other end of the main line being connected to the high-pressure gas cylinder, the drilling simulation pipe being equipped with the upper end of the support leg, the support leg being liftable, and the grouting system being equipped in the drilling simulation pipe; The specific steps include: S1, connect the high-pressure gas cylinder, the gas cylinder pressure gauge, the gas cylinder valve, and the gas outflow pipe network in sequence, and install the branch pipe valve and branch pipe pressure gauge on each gas branch pipe of the gas outflow pipe network in sequence; S2, a drilling simulation tube with one end open and the other end closed with a flange, serving as the bottom of the simulated hole. A group of sieve holes are arranged at regular intervals on the drilling simulation tube. Gas outlet casings are sleeved on the drilling simulation tube. Multiple gas outlet casings are placed at the sieve holes, and the gas branch pipes are connected to the gas outlet casings. S3. Install several support legs for fixing and adjusting the drilling simulation tube. The installation order of a single support leg is to install the stabilizing plate, adjusting bolt, adjusting tube, movable connecting buckle and drilling tube fixing sleeve from bottom to top, and fix the drilling simulation tube through the drilling tube fixing sleeve. S4, connecting the rear end sealing capsule and the front end sealing capsule to the grouting pipe, and sequentially inserting the rear end sealing capsule, the grouting pipe bursting valve and the front end sealing capsule into the drilling simulation pipe, installing an exhaust pipe on the front end sealing capsule, installing an exhaust pipe valve on the exhaust pipe, and installing a grouting pipe valve on the grouting pipe; S5, install a grouting pressure gauge and a grouting hose on the grouting pump, and connect the grouting hose and the grouting pipe; S6, adjust the height of the support legs by adjusting the bolts and adjusting the tubes, and then adjust the spatial layout and angle of the drilling simulation tubes to obtain the following spatial forms of drilling:

1. Nearly horizontal drilling with a drilling inclination of -5° to 5°; 2. Drilling holes with an inclination angle greater than 5° and monotonously ascending; 3. Drill holes with an inclination angle of less than -5° and monotonously descending; 4. The drilling trajectory presents a concave drilling; 5. The drilling trajectory presents a convex drilling; Simulate the spatial form of one of the boreholes; S7, opening the gas cylinder valve to allow the high-pressure gas in the high-pressure gas cylinder to enter the gas outflow pipe network, and at the same time controlling the branch pipe valve on each gas branch pipe so that the value of each branch pipe pressure gauge reaches the designed value, and the gas enters the borehole simulation pipe through the gas outlet casing and the sieve hole, simulating the flow of coal seam gas in the borehole; S8, turning on the grouting pump, adjusting the grouting pressure according to the data displayed on the grouting pressure gauge so that the grouting pressure meets the experimental design requirements, opening the grouting pipe valve, opening the exhaust pipe valve, and allowing the slurry to enter the front-end sealing capsule and the rear-end sealing capsule through the grouting pipe. When the grouting pressure reaches the critical value of the grouting pipe bursting valve, the grouting pipe bursting valve ruptures, and the slurry enters the grouting space between the front-end sealing capsule and the rear-end sealing capsule; S9, during the process of continuous injection of slurry into the grouting space, the gas entering from the gas outlet casing and the sieve hole continuously surges out to disturb the slurry, and at the same time, the gas is discharged from the exhaust pipe valve. When slurry flows out of the exhaust pipe valve, it means that most of the gas in the grouting space has been discharged. The exhaust pipe valve is closed and high-pressure grouting is continued until the hole is sealed. The slurry flow pattern was observed during the grouting process, and the slurry was taken out and measured after solidification to obtain the bonding strength; S10, repeating steps S6 to S9, simulating different borehole spatial forms, implementing slurry coagulation experiments under different borehole spatial forms, and obtaining slurry flow patterns and bonding strengths under different borehole spatial forms.

2. The method for testing the effect of multi-angle drilling and sealing under gas outflow conditions according to claim 1, characterized in that: In step S8, the number of front-end sealing capsules or rear-end sealing capsules is increased or decreased, the length of the exhaust pipe and the grouting pipe is adjusted, and the installation position of the grouting pipe burst valve is changed to achieve different grouting methods.

3. The method for testing the effect of multi-angle drilling and sealing under gas outflow conditions according to claim 1, characterized in that: In step S9, during the grouting process, the branch pipe valve is controlled to adjust the pressure and flow of the injected gas, the grouting pipe valve is adjusted to change the grouting pressure, the exhaust pipe valve is opened and closed in stages multiple times, and the gas and clean water in the slurry are discharged to realize a slurry coagulation experiment under the influence of multiple parameter environments in the spatial form of a borehole.

4. The method for testing the effect of multi-angle drilling and sealing under gas outflow conditions according to claim 1, characterized in that: The main pipe is equipped with a gas cylinder pressure gauge and a gas cylinder valve, and the gas branch pipe is equipped with a branch pipe valve and a branch pipe pressure gauge.

5. The method for testing the effect of multi-angle drilling and sealing under gas outflow conditions according to claim 1, characterized in that: The diameter of the drilling simulation tube is 65 mm to 130 mm, one end of the drilling simulation tube is open and the other end is fixedly installed with a flange.

6. The method for testing the effect of multi-angle drilling and sealing under gas outflow conditions according to claim 1, characterized in that: The supporting leg includes a stabilizing plate, an adjusting bolt, an adjusting tube, a movable connecting buckle and a drilling tube fixing sleeve. The adjusting bolt is fixedly mounted on the stabilizing plate, and the adjusting bolt is threaded into the adjusting tube. The movable connecting buckle is rotatably assembled on the upper end of the adjusting tube. The drilling tube fixing sleeve is fixedly mounted on the movable connecting buckle, and the drilling simulation tube is assembled in the drilling tube fixing sleeve.

7. The method for testing the effect of multi-angle drilling and sealing under gas outflow conditions according to claim 1, characterized in that: The grouting system includes a grouting pump and a grouting hole sealer, and the output end of the grouting pump is equipped with a grouting pressure gauge and a grouting hose.

8. The method for testing the effect of multi-angle drilling and sealing under gas outflow conditions according to claim 7, characterized in that: The grouting sealer includes a front-end sealing capsule, a rear-end sealing capsule, an exhaust pipe and a grouting pipe. The front-end sealing capsule and the rear-end sealing capsule are assembled in the drilling simulation pipe. The front-end sealing capsule is close to the opening of the drilling simulation pipe, and the rear-end sealing capsule is located inside the drilling simulation pipe. The space between the front-end sealing capsule and the rear-end sealing capsule in the drilling simulation pipe is the grouting space. The exhaust pipe and the grouting pipe both pass through the front-end sealing capsule. The inner end of the exhaust pipe is located in the grouting space, and the outer end of the exhaust pipe is located outside the opening. The outer end of the exhaust pipe is equipped with an exhaust pipe valve. The inner end of the grouting pipe is located in the rear-end sealing capsule, and the outer end of the grouting pipe is connected to the grouting hose. The outer end of the grouting pipe is equipped with a grouting pipe valve. The grouting pipe is equipped with a grouting pipe bursting valve, and the grouting pipe bursting valve is located in the grouting space.

9. The method for testing the effect of multi-angle drilling and sealing under gas outflow conditions according to claim 8, characterized in that: The grouting pipe is equipped with a one-way valve, and there are two one-way valves in total. The two one-way valves are respectively located in the front end sealing capsule and the rear end sealing capsule.

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