Inhibition liquid seepage law research system and method based on grouting and liquid plugging measures

Abstract

The invention provides a inhibition liquid seepage law research system and method based on grouting and liquid plugging measures. The inhibition liquid seepage law research system comprises a transparent coal seam fracture visual model, a high-speed camera, injection equipment and a control system. The injection equipment injects a plugging material into the coal seam fracture visual model to form a plugging layer; then, a blocking liquid is injected into a large fracture of the coal seam fracture visualization model, the blocking liquid permeates in the large fracture and the small fracture, the blocking layer is pushed to come out of the large fracture, the blocking liquid infiltrates coal bodies near the large fracture and the small fracture, a high-speed camera shoots the infiltration range of the blocking liquid, and therefore a seepage effect image of the blocking liquid is obtained; the control system collects and processes data of the high-speed camera and the injection equipment, and the injection pressure and flow velocity of the plugging material with the optimal seepage effect are obtained. The seepage process of the inhibition liquid is directly observed, the convenience of research on the seepage law of the inhibition liquid is improved, and theoretical basis and technical support are provided for coal spontaneous combustion prevention and control.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal mine safety, in particular to a system and method for studying seepage law of blocking liquid based on grouting liquid blocking measures. BACKGROUND

[0002] In coal mining, coal spontaneous combustion is one of the key hidden dangers threatening mine safety, causing resource waste and environmental damage. To inhibit coal spontaneous combustion, blocking liquid can be injected into the coal seam to reduce the oxidation activity of the coal body and achieve the purpose of fire prevention. However, at the end stage of coal mining, the intact coal body such as top coal and residual coal pillars is prone to form a large number of complex fracture networks. These fractures constitute "advantageous seepage channels", causing the injected blocking liquid to leak invalidly, resulting in serious non-uniformity of coal body immersion and weakening the effect of coal spontaneous combustion control, also causing waste of blocking liquid.

[0003] In order to avoid the waste of blocking liquid caused by the above-mentioned fractures, a blocking layer can be formed by using a blocking material to block the coal seam fractures, and then the blocking liquid is injected to seep in the fractures and immerse the coal body. However, the actual coal seam environment is not visible, and the seepage process of the blocking liquid cannot be directly observed, which may cause inconvenience in the study of the seepage law of the blocking liquid. SUMMARY

[0004] The present application aims to provide a system and method for studying the seepage law of blocking liquid based on grouting liquid blocking measures, so as to directly observe the seepage process of the blocking liquid and improve the convenience of the study of the seepage law of the blocking liquid, providing a theoretical basis and technical support for the prevention and control of coal spontaneous combustion.

[0005] To this end, the technical scheme adopted by the present application is: a blocking liquid seepage law research system based on grouting liquid blocking measures, comprising a base and an experimental support, the experimental support is fixedly installed on the base, and a placing support is fixedly installed in the middle, further comprising a transparent coal seam fracture visualization model, a buffer tank, a liquid storage tank, a high-speed camera, an injection device and a control system; the placing support is sequentially fixedly installed with a placing tray, a mounting block and a fixing block, a receiving container is placed on the placing tray, the coal seam fracture visualization model is fixedly installed on the mounting block, the buffer tank and the liquid storage tank are fixedly installed at both ends of the coal seam fracture visualization model respectively, and are respectively provided with an injection port and a discharge port, a large fracture with a width of 1-10mm and a plurality of small fractures with a width of less than 0.5mm are arranged in the coal seam fracture visualization model, the large fracture is communicated with the buffer tank, the liquid storage tank and the small fractures, the receiving container corresponds to the discharge port, so as to receive the blocking layer discharged from the discharge port; the injection device comprises a stirrer, a delivery pump, a pressure gauge, a flow meter, an electric valve and an injection pipe which are sequentially connected, the injection pipe is fixedly connected with the fixing block, and the outlet end is connected with the injection port; the high-speed camera is fixedly installed at the top end of the experimental support and corresponds to the coal seam fracture visualization model, so as to shoot the images of the blocking liquid seepage process and the infiltration range; the control system is electrically connected with the high-speed camera, the delivery pump, the pressure gauge, the flow meter and the electric valve.

[0006] As a preferred embodiment of the above-mentioned scheme, the length, width and height of the coal seam fracture visualization model are 200mm, 120mm and 20mm respectively.

[0007] Further preferably, a protective tube is fixedly installed outside the injection pipe.

[0008] Further preferably, the material of the coal seam fracture visualization model is transparent photosensitive resin.

[0009] Further preferably, the receiving container is a beaker.

[0010] A blocking liquid seepage law research method based on grouting liquid blocking measures, comprising the following steps:

[0011] S1, a plurality of transparent coal seam fracture visualization models are prepared, and then the first coal seam fracture visualization model, a buffer tank, a liquid storage tank, a high-speed camera, an injection device and a receiving container are installed on the experimental support and the placing support;

[0012] S2, a plurality of experimental scheme groups are designed, each of which comprises a plurality of experimental schemes, the injection pressure of the plugging material in the same experimental scheme group is the same, and the flow rate of the plugging material in the same experimental scheme group is increased by 1 mL / min in turn, the injection pressure of the plugging material in the plurality of experimental scheme groups is increased by 0.2 MPa in turn, and the injection pressure range and the flow rate range of the plugging material are 1-2 MPa and 30-36 mL / min respectively; the injection pressure of the blocking solution in each of the experimental schemes is 1 MPa, and the flow rate of the blocking solution in each of the experimental schemes is 30 mL / min, the injection pressure and the flow rate of the plugging material in the first experimental scheme are 1 MPa and 30 mL / min respectively;

[0013] S3, when the experimental scheme is implemented, the plugging material is put into the stirrer and stirred uniformly, the control system is used to control the start of the delivery pump and the opening of the electric valve, and the plugging material in the stirrer is injected into the buffer tank through the injection pipe at a set injection pressure and flow rate, the control system collects the data of the pressure gauge and the flowmeter, and then the plugging material seeps into the large fracture of the coal seam fracture visualization model from the buffer tank;

[0014] S4, after the injection of the plugging material is completed, the control system controls the delivery pump and the electric valve to be closed, and the plugging material spontaneously aggregates in the large fracture to form a plugging layer;

[0015] S5, the stirrer is cleaned, the blocking solution is put into the stirrer, the control system is used to control the start of the delivery pump and the opening of the electric valve, and the blocking solution in the stirrer is injected into the buffer tank through the injection pipe at a set injection pressure and flow rate, the blocking solution seeps into the large fracture from the buffer tank and pushes the plugging layer into the liquid storage tank from the large fracture, at the same time, the blocking solution seeps into the small fracture, the blocking solution infiltrates the coal body of the coal seam fracture visualization model by seeping into the large fracture and the small fracture, the high-speed camera shoots the seepage process and the infiltration range image of the blocking solution, the control system collects the data of the high-speed camera, and then the plugging layer enters the receiving container from the discharge port, and the control system closes the delivery pump and the electric valve;

[0016] S6, the remaining experimental schemes are repeated after a new coal seam fracture visualization model is replaced;

[0017] S7, the control system processes the data of the high-speed camera, the pressure gauge and the flowmeter, and sets the maximum infiltration range image of the blocking solution shot by the high-speed camera after each injection of the blocking solution as the seepage effect image of the blocking solution, so as to obtain the injection pressure and the flow rate of the plugging material with the best seepage effect of the blocking solution.

[0018] Preferably, the plugging material comprises nano-silica sol, deionized water, organic phosphonate retarder and nano calcium carbonate, and the mass ratio of the nano-silica sol, deionized water, organic phosphonate retarder and nano calcium carbonate is 30%, 65%, 3% and 2% respectively.

[0019] Further preferably, the high-speed camera shoots at a frequency of 10000 frames per second.

[0020] The present application has the following advantages:

[0021] 1. The coal seam fracture visualization model, buffer tank, liquid storage tank, high-speed camera, injection equipment and control system can be used to directly observe the seepage process and infiltration range of the blocking liquid under different injection pressures and flow rates of the plugging material, the same injection pressure and different flow rates, and different injection pressures and the same flow rate, thereby improving the convenience of the blocking liquid seepage law research and providing a theoretical basis and technical support for the prevention and control of coal spontaneous combustion.

[0022] 2. The transparent coal seam fracture visualization model can be used to visually reproduce the complex fracture network of the coal seam.

[0023] 3. The plugging material cannot enter small fractures with a width less than 0.5mm, but can enter large fractures with a width of 1-10mm as the dominant seepage channel, thereby forming a plugging layer to effectively plug only the large fractures. When the injection pressure and flow rate of the blocking liquid are 1MPa and 30mL / min respectively, and the injection pressure and flow rate of the plugging material are 1MPa and 30mL / min respectively, the plugging layer formed by the plugging material can slowly migrate along the large fractures under the driving of the blocking liquid seepage pressure to achieve temporary plugging, allowing the blocking liquid to fully infiltrate around the large fractures and small fractures. This facilitates direct observation of the seepage of the blocking liquid on the coal seam fracture visualization model, and avoids the problem of permanent plugging of the large fractures which requires multiple borehole injections of the blocking liquid.

[0024] 4. A correlation research system of the injection pressure and flow rate of the plugging material and the seepage effect of the blocking liquid is constructed. By changing the injection pressure and flow rate of the plugging material, different seepage effects of the blocking liquid can be displayed, thereby providing a reference for the collaborative optimization of the injection pressure and flow rate of the plugging material and the seepage effect of the blocking liquid. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a structural schematic diagram of the blocking liquid seepage law research system based on the grouting plugging liquid measure of the present application.

[0026] Figure 2 is a structural schematic diagram of the injection equipment of the present application.

[0027] Figure 3is a state diagram of a coal seam fracture visualization model when a plugging material forms a plugging layer in the present application.

[0028] Figure 4 is a state diagram of a coal seam fracture visualization model discharging a plugging layer in the present application. DETAILED DESCRIPTION

[0029] The present application is further described below in conjunction with the accompanying drawings and examples.

[0030] As shown in the drawings, Figures 1-4 A system for studying the seepage law of blocking liquid based on grouting plugging measures, comprising a base 1 and an experimental support 3, the experimental support 3 being fixedly installed on the base 1 and having a placement support 2 fixedly installed in the middle, and further comprising a transparent coal seam fracture visualization model 16, a buffer tank 15, a liquid storage tank 5, a high-speed camera 17, an injection device, and a control system.

[0031] The placement support 2 has a placement tray 6, a mounting block 7, and a fixing block 13 fixedly installed in sequence, and a receiving container 4 is placed on the placement tray 6, the coal seam fracture visualization model 16 is fixedly installed on the mounting block 7, the buffer tank 15 and the liquid storage tank 5 are fixedly installed at both ends of the coal seam fracture visualization model 16, respectively, and are respectively provided with an injection inlet 19 and a discharge outlet, the coal seam fracture visualization model 16 is provided with a large fracture 21 with a width of 1-10 mm and a plurality of small fractures 20 each with a width of less than 0.5 mm, the large fracture 21 communicates with the buffer tank 15, the liquid storage tank 5, and the small fractures 20, and the receiving container 4 corresponds to the discharge outlet to facilitate receiving the plugging layer discharged from the discharge outlet.

[0032] The injection device comprises a stirrer 10, a delivery pump 11, a pressure gauge 12, a flow meter 9, an electric valve 8, and an injection pipe 14 connected in sequence, the injection pipe 14 is fixedly connected to the fixing block 13, and the outlet end is connected to the injection inlet 19.

[0033] The high-speed camera 17 is fixedly installed at the top end of the experimental support 3 and corresponds to the coal seam fracture visualization model 16 to facilitate shooting the images of the seepage process and the infiltration range of the blocking liquid.

[0034] The control system is electrically connected to the high-speed camera 17, the delivery pump 11, the pressure gauge 12, the flow meter 9, and the electric valve 8.

[0035] The control system can collect and process data of the high-speed camera 17, the pressure gauge 12 and the flow meter 9 in real time, so as to dynamically monitor the experimental process, and can control the injection pressure and flow rate of the plugging material and the blocking liquid by controlling the delivery pump 11 and the electric valve 8 through the data of the pressure gauge 12 and the flow meter 9. The control system is prior art, which will not be described in detail here. The pressure gauge 12 can detect the injection pressure of the plugging material and the blocking liquid, and the flow meter 9 can detect the flow rate of the plugging material and the blocking liquid.

[0036] The protection pipe 18 is fixedly installed outside the injection pipe 14, and the receiving container 4 is a beaker.

[0037] The protection pipe 18 can protect the injection pipe 14, improving the safety of the injection pipe 14. The receiving container 4 is a beaker, which can receive the plugging layer 22 through the top opening.

[0038] A method for studying the seepage law of blocking liquid based on the grouting plugging liquid measure, comprising the following steps:

[0039] S1, a plurality of transparent coal seam fracture visualization models 16 are prepared, and then the first coal seam fracture visualization model 16, the buffer tank 15, the liquid storage tank 5, the high-speed camera 17, the injection equipment and the receiving container 4 are installed on the experimental support 3 and the placing support 2.

[0040] After the coal seam is sampled, a coal column with a diameter of 50 mm and a height of 100 mm is made, the coal column is CT scanned, the three-dimensional data of local coal body fracture size, distribution and connectivity are selected, a fracture network digital model is constructed using CT data processing software, the constructed model is imported into the printer control software, transparent photosensitive resin is selected as the printing material, and a plurality of coal seam fracture visualization models 16 with a size of 200mm*120mm*20mm are prepared.

[0041] S2, a plurality of experimental scheme groups are designed, each experimental scheme group comprises a plurality of experimental schemes, the injection pressure of the plugging material of the plurality of experimental schemes in the same experimental scheme group is the same, and the flow rate is increased by an ascending gradient of 1 mL / min in turn, the injection pressure of the plugging material of the plurality of experimental scheme groups is increased by an ascending gradient of 0.2 MPa in turn, and the injection pressure range and the flow rate range of the plugging material are 1-2 MPa and 30-36 mL / min respectively. The injection pressure of the blocking liquid of each experimental scheme is 1 MPa, and the flow rate is 30 mL / min. The injection pressure and the flow rate of the plugging material of the first experimental scheme are 1 MPa and 30 mL / min respectively.

[0042] S3, when the experimental scheme is implemented, the plugging material is put into the stirrer 10 and stirred uniformly, the control system is used to control the starting of the delivery pump 11 and the opening of the electric valve 8, and the plugging material in the stirrer 10 is injected into the buffer tank 15 through the injection pipe 14 at a set injection pressure and flow rate, the control system collects the data of the pressure gauge 12 and the flowmeter 9, and then the plugging material seeps from the buffer tank 15 into the large fissure 21 of the coal seam fissure visualization model 16.

[0043] The plugging material is a nano-silica sol composite plugging material, which comprises nano-silica sol, deionized water, organic phosphonate retarder and nano-calcium carbonate, and the mass proportions of the nano-silica sol, deionized water, organic phosphonate retarder and nano-calcium carbonate are 30%, 65%, 3% and 2% respectively. The plugging material has good fluidity before gelation and can quickly reach the large fissure 21, and after gelation (i.e. forming the plugging layer 22), the plugging layer 22 can slowly move under pressure with the injection and seepage of the resistance liquid, so as to ensure the uniform diffusion of the resistance liquid along the large fissure 21 as the dominant seepage channel to the surrounding.

[0044] When preparing the plugging material, the nano-silica sol, deionized water, organic phosphonate retarder and nano-calcium carbonate are mixed and put into the stirrer 10, and low-speed stirring is performed for 5-10 min to ensure uniform dispersion of the system.

[0045] S4, after the plugging material is injected, the control system controls the closing of the delivery pump 11 and the electric valve 8, and the plugging material spontaneously agglomerates in the large fissure 21 to form the plugging layer 22.

[0046] After the plugging material seeps into the large fissure 21, the organic phosphonate retarder will gradually lose its effectiveness, and the nano-silica sol particles spontaneously agglomerate to form a high-strength silica gel plugging layer after 3-4 hours.

[0047] S5, the stirrer 10 is cleaned, the resistance liquid is put into the stirrer 10, the control system is used to control the starting of the delivery pump 11 and the opening of the electric valve 8, and the resistance liquid in the stirrer 10 is injected into the buffer tank 15 through the injection pipe 14 at a set injection pressure and flow rate, the resistance liquid seeps into the large fissure 21 from the buffer tank 15 and pushes the plugging layer 22 into the liquid storage tank 5 from the large fissure 21, at the same time, the resistance liquid seeps into the small fissure 20, the resistance liquid infiltrates the coal body of the coal seam fissure visualization model 16 by seeping into the large fissure 21 and the small fissure 20, the high-speed camera 17 shoots the seepage process and the infiltration range image of the resistance liquid, the control system collects the data of the high-speed camera 17, and then the plugging layer 22 enters the receiving container 4 from the discharge port, and the control system closes the delivery pump 11 and the electric valve 8.

[0048] Since the resistance to pressure of the plugging layer 22 is less than the seepage pressure of the blocking liquid, the plugging layer 22 is slowly pushed to the liquid storage tank 5 by the blocking liquid, so that the blocking liquid can infiltrate the coal body around the large fissure 21 and the small fissure 20 which are left by the movement of the plugging layer 22. With the continuous seepage of the blocking liquid, the plugging layer 22 will continue to advance until the plugging layer 22 is completely pushed out of the discharge port into the receiving container 4. The high-speed camera 17 takes pictures at a frequency of 10,000 frames per second.

[0049] S6, the remaining experimental schemes are repeated steps S3-S5 after replacing a new coal seam fissure visualization model 16.

[0050] S7, the control system processes the data of the high-speed camera 17, the pressure gauge 12 and the flow meter 9, and sets the maximum infiltration range image of the blocking liquid taken by the high-speed camera 17 after each injection of the blocking liquid as the seepage effect image of the blocking liquid, so as to obtain the injection pressure and flow rate of the plugging material with the optimal seepage effect of the blocking liquid.

[0051] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and purposes of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A system for studying the seepage law of inhibiting liquid based on grouting and plugging measures, comprising a base (1) and an experimental support (3), wherein the experimental support (3) is fixedly installed on the base (1), and a placement support (2) is fixedly installed in the middle, characterized in that: The transparent coal seam fissure visualization model (16), the buffer tank (15), the liquid storage tank (5), the high-speed camera (17), the injection device and the control system are further included. The placing support (2) is sequentially fixedly provided with a placing tray (6), a mounting block (7) and a fixing block (13), the placing tray (6) is provided with a receiving container (4), the coal seam fissure visualization model (16) is fixedly installed on the mounting block (7), the buffer tank (15) and the liquid storage tank (5) are fixedly installed at two ends of the coal seam fissure visualization model (16) respectively and are respectively provided with an injection inlet (19) and a discharge outlet, the coal seam fissure visualization model (16) is provided with a large fissure (21) with a width of 1-10 mm and a plurality of small fissures (20) with a width of less than 0.5 mm, the large fissure (21) is communicated with the buffer tank (15), the liquid storage tank (5) and the small fissures (20), and the receiving container (4) corresponds to the discharge outlet, so as to receive the sealing layer discharged from the discharge outlet. The injection device sequentially comprises a stirrer (10), a delivery pump (11), a pressure gauge (12), a flow meter (9), an electric valve (8) and an injection pipe (14), the injection pipe (14) is fixedly connected to the fixing block (13) and is connected to the injection inlet (19) at an outlet end. The high-speed camera (17) is fixedly installed at a top end of the experimental support (3) and corresponds to the coal seam fissure visualization model (16), so as to shoot images of the blocking liquid seepage process and the infiltration range. The control system is electrically connected to the high-speed camera (17), the delivery pump (11), the pressure gauge (12), the flow meter (9) and the electric valve (8).

2. The system for studying the seepage law of blocking liquid based on the grouting liquid plugging measure according to claim 1, characterized in that: The length, the width and the height of the coal seam fissure visualization model (16) are 200 mm, 120 mm and 20 mm respectively.

3. The system for studying the seepage law of blocking liquid based on the grouting liquid plugging measure according to claim 1, characterized in that: The injection pipe (14) is fixedly provided with a protection pipe (18) outside.

4. The system for studying the seepage law of blocking liquid based on the grouting liquid plugging measure according to claim 1, characterized in that: The material of the coal seam fissure visualization model (16) is transparent photosensitive resin.

5. The system for studying the seepage law of blocking liquid based on the grouting liquid plugging measure according to claim 1, characterized in that: The receiving container (4) is a beaker.

6. A method for studying the seepage law of blocking liquid based on the grouting liquid blocking measure, characterized in that, The blocking liquid seepage law research system based on the grouting sealing liquid measure comprises the following steps: S1, a plurality of transparent coal seam fissure visualization models (16) are prepared, then a first coal seam fissure visualization model (16) and a buffer tank (15), a liquid storage tank (5), a high-speed camera (17), an injection device and a receiving container (4) are installed on an experimental support (3) and a placing support (2); S2, the buffer tank (15) is filled with a sealing liquid, the delivery pump (11) is started to drive the sealing liquid to flow into the coal seam fissure visualization model (16) through the injection pipe (14) and the injection inlet (19), the high-speed camera (17) is started to shoot images of the blocking liquid seepage process and the infiltration range, and the control system is started to control the delivery pump (11), the pressure gauge (12), the flow meter (9) and the electric valve (8). S2, design multiple experimental scheme groups, the experimental scheme groups include multiple experimental schemes, the injection pressure of the plugging material of the multiple experimental schemes of the same experimental scheme group is the same, and the flow rate is increased by 1 mL / min in turn, the injection pressure of the multiple experimental scheme groups is increased by 0.2 MPa in turn, the injection pressure range and the flow rate range of the plugging material are 1-2 MPa and 30-36 mL / min respectively; the injection pressure of the blocking liquid of each experimental scheme is 1 MPa, and the flow rate is 30 mL / min, the injection pressure and the flow rate of the first experimental scheme are 1 MPa and 30 mL / min respectively; S3, when the experimental scheme is implemented, the plugging material is put into the stirrer (10) and stirred uniformly, the control system is used to control the start of the delivery pump (11) and the opening of the electric valve (8), and the plugging material in the stirrer (10) is injected into the buffer tank (15) through the injection pipe (14) at a set injection pressure and flow rate, the control system collects the data of the pressure gauge (12) and the flow meter (9), and then the plugging material seeps into the large fracture (21) of the coal seam fracture visualization model (16) from the buffer tank (15); S4, after the injection of the plugging material is completed, the control system controls the delivery pump (11) and the electric valve (8) to be closed, and the plugging material spontaneously aggregates in the large fracture (21) to form a plugging layer (22); S5, clean the stirrer (10), put the blocking liquid into the stirrer (10), use the control system to control the start of the delivery pump (11) and the opening of the electric valve (8), and inject the blocking liquid in the stirrer (10) into the buffer tank (15) through the injection pipe (14) at a set injection pressure and flow rate, the blocking liquid seeps into the large fracture (21) from the buffer tank (15) and pushes the plugging layer (22) into the liquid storage tank (5) from the large fracture (21), at the same time, the blocking liquid seeps into the small fracture (20), the blocking liquid seeps into the coal body of the coal seam fracture visualization model (16) through the large fracture (21) and the small fracture (20), the high-speed camera (17) shoots the seepage process and the imbibition range image of the blocking liquid, the control system collects the data of the high-speed camera (17), and then the plugging layer (22) enters the receiving container (4) from the discharge port, and the control system closes the delivery pump (11) and the electric valve (8); S6, repeat steps S3-S5 after replacing the new coal seam fracture visualization model (16); S7, the control system processes the data of the high-speed camera (17), the pressure gauge (12) and the flow meter (9), and sets the maximum imbibition range image of the blocking liquid shot by the high-speed camera (17) after each injection of the blocking liquid as the seepage effect image of the blocking liquid, so as to obtain the injection pressure and flow rate of the plugging material with the best seepage effect of the blocking liquid.

7. The method according to claim 6, characterized in that: The plugging material comprises nanometer silicon sol, deionized water, organic phosphonate retarder and nanometer calcium carbonate, and the mass proportions of the nanometer silicon sol, deionized water, organic phosphonate retarder and nanometer calcium carbonate are 30%, 65%, 3% and 2% respectively.

8. The method according to claim 6, characterized in that: The high-speed camera (17) takes pictures at a frequency of 10,000 frames per second.

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