Water inrush and sand inrush fracture flow experimental device

Abstract

The utility model discloses a water inrush and sand inrush fracture flow experiment device, which relates to the technical field of coal mining and comprises a shell, a water supply module, a water-sand mixture module, a fracture network module, a collection module, a test module and a monitoring module, the water-sand mixture module and the fracture network module are both positioned in the shell, and the shell is made of transparent materials. The water supply module is connected with the water inlet end of the water-sand mixture module, the water outlet end of a water-sand mixture is connected with the water inlet end of the fracture network module through the permeable element, the water outlet end of the fracture network module is connected with the collection module, the collection module is connected with the test module, and collected objects are weighed through the test module. The monitoring module is located on the periphery of the fracture network module and used for obtaining a three-dimensional model of the fracture network module in real time and monitoring the fracture flow condition in the fracture network module. According to the utility model, the water inrush and sand inrush fracture flow experiment is visible and can be reused.

Description

Technical Field

[0001] The utility model relates to the technical field of coal mining, in particular to a water bursting sand bursting fissure flow experimental device. Background Art

[0002] The North China region of my country is rich in groundwater resources. Due to the poor cementation of semi-consolidated sandstone itself, a large amount of groundwater will surge up during coal excavation. When the sandstone aquifer is saturated with water, the sandstone will have a certain fluidity. When the water-conducting fractures affect the sandstone aquifer on the roof of the coal seam, the equilibrium state of the original flow field of the aquifer is broken, and it rapidly decreases at the water-gushing channel. Under the action of the water head difference, the sand particles generate dynamic water pressure, forming a hydraulic gradient along the direction of hydraulic depth change. The greater the initial water head height of the aquifer, the greater the hydraulic gradient formed. When it exceeds the critical hydraulic gradient of the sandstone aquifer, there will be a danger of water filling and sand bursting.

[0003] At present, the models for studying the mechanism of sandification mainly include the following three aspects: (1) measurement of the phase content of water inrush and sand burst. By simulating water inrush and sand burst experiments under different geological conditions, the migration characteristics of sand particles under the action of water flow in the process of water inrush and sand burst are determined, such as the Chinese patent "Device and method for measuring the phase content of water inrush and sand burst in water inrush and sand burst experiments" with publication number CN112362849A; (2) the flow law of water and sand in water inrush and sand burst under complex strata. The distribution conditions of complex strata are taken into account in the experiment to make it more realistic and close to the actual situation, such as the Chinese patent "A water inrush and sand burst water and sand migration simulation test device and test method" with publication number CN114264792A; (3) by adjusting the molding panel to prepare simulation plates of different sizes and different fracture surface shapes, it is possible to simulate water inrush and sand burst experiments with fractures of different shapes, such as the Chinese patent "A mining-induced three-dimensional fracture simulation plate preparation device and water inrush and sand burst simulation method" with publication number CN114675004A. However, none of the above technologies can visually observe the movement of water and sand during the entire experiment. It is difficult to make a reasonable explanation for the entire sand production mechanism by only measuring the water and sand mass in the collection device and the pressure data of the sensor. In addition, some of the above technologies cannot be applied to experiments with different fracture grids, and the reusability of the devices is poor.

[0004] Therefore, establishing a transparent experimental device with visible internal changes is of great significance for studying the sand production mechanism. Utility Model Content

[0005] The utility model aims to provide a water bursting sand bursting fissure flow experimental device to solve the problems existing in the above-mentioned prior art, so as to make the water bursting sand bursting fissure flow experiment visible and reusable.

[0006] To achieve the above purpose, the utility model provides the following solutions:

[0007] The utility model provides a water burst and sand burst fissure flow experimental device, comprising a shell, a water supply module, a water-sand mixture module, a fracture network module, a collection module, a test module and a monitoring module, wherein the water-sand mixture module and the fracture network module are both located in the shell, and the shell is made of a transparent material, the water supply module is connected to the water inlet end of the water-sand mixture module, the water outlet end of the water-sand mixture is connected to the water inlet end of the fracture network module through a permeable element, the water outlet end of the fracture network module is connected to the collection module, the collection module is connected to the test module, and the collection is weighed through the test module, the monitoring module is located at the periphery of the fracture network module, and is used for obtaining a three-dimensional model of the fracture network module in real time and monitoring the fracture flow conditions in the fracture network module.

[0008] Preferably, the water-sand mixture module comprises a plurality of simulated gravels of different particle sizes stacked together.

[0009] Preferably, the simulated gravel is quartz sand.

[0010] Preferably, the water permeable element is a gauze mesh, and the simulated gravel is divided into two groups, one group of simulated gravel is white and has a particle size larger than the pore size of the gauze mesh, and the other group of simulated gravel is black and has a particle size smaller than the pore size of the gauze mesh.

[0011] Preferably, the test module is a weighing element, which is located at the lower end of the collecting module and is used to weigh the water and the black simulated gravel in the collecting module.

[0012] Preferably, the fracture network module comprises several groups of elastic filling bodies and a plurality of fracture units of different shapes, fractures are formed between adjacent fracture units, each group of the elastic filling bodies is located on one side of a different fracture unit, and the elastic filling bodies are used to squeeze the corresponding fracture units and close the corresponding fractures, and the elastic filling body is provided with a pressure detection element on the side away from the corresponding fracture.

[0013] Preferably, the elastic filling body is a spring, and the pressure detection element is a soil pressure box.

[0014] Preferably, a high-pressure pump is provided at the water supply module.

[0015] Preferably, the monitoring module includes a laser emitter and multiple high-speed cameras, wherein the multiple high-speed cameras are respectively located in different directions around the periphery of the crack network module and are used to take pictures of the crack network module, and the laser emitter is used to monitor the size and position of the cracks in the crack network module.

[0016] Compared with the prior art, the utility model has achieved the following technical effects:

[0017] 1. The housing in the utility model is made of transparent material, so that the entire experimental process can be observed from the outside and recorded by a camera, and the state of the fracture network module during the test can be clearly and intuitively recorded;

[0018] 2. The utility model can simulate and analyze the three-dimensional fracture network through the setting of the fracture network module;

[0019] 3. The utility model can form a fracture network module by selecting fracture units of different shapes and numbers to simulate different fracture widths, fracture intersection angles, fracture numbers and combination forms, etc., so that the overall application range is wider and can be reused. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 This is a schematic diagram of the structure of the fracture network module and the water-sand mixture module in the utility model;

[0022] Figure 2 It is a schematic diagram of the position of the elastic filling body in the utility model;

[0023] In the figure: 1-simulated gravel, 2-gauze mesh, 3-crack, 4-crack unit, 5-elastic filling body, 6-earth pressure box. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0025] The utility model aims to provide a water bursting sand bursting fissure flow experimental device to solve the problems existing in the prior art and make the water bursting sand bursting fissure flow experiment visible and reusable.

[0026] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0027] like Figure 1-Figure 2 As shown, the present embodiment provides a water inrush and sand burst fissure flow experimental device, comprising a shell, a water supply module, a water-sand mixture module, a fracture network module, a collection module, a test module and a monitoring module. The water-sand mixture module and the fracture network module are both located in the shell, and the shell is made of a transparent material, preferably transparent acrylic, so that the entire experimental process can be observed from the outside and recorded by a camera, and the state of the fracture network module during the test can be clearly and intuitively recorded, so as to achieve an accurate record of the particle movement state during the entire experimental process. The water supply module is connected to the water inlet end of the water-sand mixture module, preferably directly connected through a hose, the water outlet end of the water-sand mixture is connected to the water inlet end of the fracture network module through a permeable element, the water outlet end of the fracture network module is connected to the collection module, the collection module is connected to the test module, and the collection is weighed through the test module. The monitoring module is located at the periphery of the fracture network module, and is used to obtain a three-dimensional model of the fracture network module in real time and monitor the fracture 3 flow conditions in the fracture network module, thereby achieving simulation analysis of the three-dimensional fracture network.

[0028] Specifically, the sand mixture module includes a plurality of simulated gravels 1 of different particle sizes stacked together. The simulated gravel 1 is used to simulate the sand source. Different grading conditions can be achieved by changing the particle size of the simulated gravel 1. Different types of sand sources can be achieved by changing the surface roundness of the simulated gravel 1. In this way, the water inrush and sand burst process can be realized, and the expansion process of single fluids such as water-sand mixture / water / slurry in a complex fracture network can also be simulated.

[0029] The simulated gravel 1 is quartz sand, and those skilled in the art may also select other materials according to actual needs.

[0030] The water-permeable element is a gauze net 2, and the simulated gravel 1 is divided into two groups, one of which is white and has a particle size larger than the aperture of the gauze net 2, and the other is black and has a particle size smaller than the aperture of the gauze net 2. The gauze net 2 can prevent large-sized simulated gravel 1 from entering the crack network module, and the aperture of the gauze net 2 can be selected according to actual needs. The black and white simulated gravel 1 can more intuitively observe the migration of small-sized simulated gravel 1 in large-sized simulated gravel 1, and locate and monitor the crack network according to the migration of small-sized simulated gravel 1. The roughness of the surface of the crack 3 can be adjusted by selecting simulated gravel 1 of different particle sizes.

[0031] The test module is a weighing element, which is located at the lower end of the collecting module and is used to weigh the water and the black simulated gravel 1 in the collecting module.

[0032] The fracture network module includes several groups of elastic filling bodies 5 and multiple fracture units 4 of different shapes. Fractures 3 are formed between adjacent fracture units 4. A pressure block can also be set at the upper end of the fracture network module to apply pressure to simulate the expansion of fractures 3 under different surrounding rock pressures. Each group of elastic filling bodies 5 is located on one side of different fracture units 4, and the elastic filling bodies 5 are used to squeeze the corresponding fracture units 4 and make adjacent fracture units 4 close together to close the corresponding fractures 3. The setting of the elastic filling bodies 5 ensures the tightness of the closure while having a certain elasticity, so that when the fracture 3 flow flows to the closed fracture 3, the closed fracture 3 is stretched open under the action of water pressure to realize the evolution process of the fracture 3; the elastic filling body 5 is provided with a pressure detection element on the side away from the corresponding fracture 3. The critical pressure of water flushing the closed fracture 3 is related to the elastic modulus of the elastic filling body 5. Changing the properties of the elastic filling body 5 can achieve different critical pressures, thereby simulating the expansion evolution of fractures 3 of different strengths and lithologies. In actual operation, the fracture network module can be composed of fracture units 4 of different shapes and numbers to simulate different fracture widths, fracture angles, numbers and combinations of fractures 3, etc., so that the overall application range is wider and can be reused.

[0033] This embodiment divides the complex three-dimensional fracture network into simple fracture units 4 by prefabricating some basic fracture 3 models (such as horizontal fractures, vertical fractures, and simple structural fractures and non-structural fractures), and assembles the fracture network according to experimental needs, thereby realizing the modularization of the fracture network.

[0034] The elastic filling body 5 is a spring, and may also be made of gel, etc. The pressure detection element is an earth pressure box 6 , which can measure the pressure of water flow in the crack 3 .

[0035] A high-pressure pump is provided at the water supply module, and other conventional high-pressure devices may also be used to inject water into the water-sand mixture model and apply force to the water-sand mixture to cause water and small-size simulated gravel 1 to seep along the cracks 3.

[0036] The monitoring module includes a laser emitter and multiple high-speed cameras. The multiple high-speed cameras are located in different directions around the fracture network module and are used to take pictures of the fracture network module. The laser emitter is used to monitor the size and position of the fracture 3 in the fracture network module. In actual application, the laser emitter can calculate the distance based on the return time of the laser beam. When the laser beam encounters the fracture 3, the round-trip time will change. The position and size of the fracture 3 are detected based on the time change, and finally a three-dimensional fracture network model is obtained to monitor the water flow in the fracture 3.

[0037] The specific application process of this embodiment is:

[0038] S1. Assemble the crack network module;

[0039] S2. Assemble the test module, connect the water supply module to the housing, and place multiple remote-controlled cameras on the periphery of the fracture network module;

[0040] S3. Weigh the water-sand mixture module according to the test design requirements and set the weight, and place the water-sand mixture module into the corresponding position in the housing and compact it;

[0041] S4. Apply K0 pressure to the fracture network module, and then keep the load stable until the test is completed;

[0042] S5. Start the test, open the stop valve, let water flow into the water-sand mixture module, apply water pressure evenly during the experiment, keep the water pressure stable, and collect the eroded simulated gravel 1 and the outflowing water at regular intervals;

[0043] S6. After the test is completed, close the stop valve, open the top cover on the outer shell corresponding to the fracture network module, take a photo from the top of the fracture network module, weigh the mass of the outflowing water and the simulated gravel 1, then filter out the simulated gravel 1 in the water, dry it and weigh it.

[0044] The present invention uses specific examples to illustrate the principle and implementation of the present invention. The above examples are only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A water bursting sand bursting fissure flow experimental device, characterized by: It includes an outer shell, a water supply module, a water-sand mixture module, a fracture network module, a collection module, a test module and a monitoring module. The water-sand mixture module and the fracture network module are both located in the outer shell, and the outer shell is made of a transparent material. The water supply module is connected to the water inlet end of the water-sand mixture module, the water outlet end of the water-sand mixture is connected to the water inlet end of the fracture network module through a permeable element, the water outlet end of the fracture network module is connected to the collection module, the collection module is connected to the test module, and the collection is weighed through the test module. The monitoring module is located at the periphery of the fracture network module, and is used to obtain a three-dimensional model of the fracture network module in real time and monitor the fracture flow conditions in the fracture network module.

2. The water inrush and sand burst fissure flow experimental device according to claim 1 is characterized by: The water-sand mixture module comprises a plurality of simulated gravels of different particle sizes stacked together.

3. The water inrush and sand burst fissure flow experimental device according to claim 2 is characterized by: The simulated gravel is quartz sand.

4. The water inrush and sand burst fissure flow experimental device according to claim 2 is characterized by: The water-permeable element is a gauze net, and the simulated gravel is divided into two groups, one group of simulated gravel is white and has a particle size larger than the pore size of the gauze net, and the other group of simulated gravel is black and has a particle size smaller than the pore size of the gauze net.

5. The water inrush and sand burst fissure flow experimental device according to claim 2 is characterized by: The test module is a weighing element, which is located at the lower end of the collecting module and is used to weigh the water and the black simulated gravel in the collecting module.

6. The water inrush and sand burst fissure flow experimental device according to claim 1 is characterized by: The fracture network module includes several groups of elastic filling bodies and a plurality of fracture units of different shapes, fractures are formed between adjacent fracture units, each group of the elastic filling bodies is located on one side of a different fracture unit, and the elastic filling bodies are used to squeeze the corresponding fracture units and close the corresponding fractures, and the elastic filling body is provided with a pressure detection element on the side away from the corresponding fracture.

7. The water inrush and sand burst fissure flow experimental device according to claim 6, characterized in that: The elastic filling body is a spring, and the pressure detection element is a soil pressure box.

8. The water inrush and sand burst fissure flow experimental device according to claim 1 is characterized by: The water supply module is provided with a high-pressure pump.

9. The water inrush and sand burst fissure flow experimental device according to claim 1, characterized in that: The monitoring module includes a laser emitter and multiple high-speed cameras. The multiple high-speed cameras are respectively located in different directions around the crack network module and are used to take pictures of the crack network module. The laser emitter is used to monitor the size and position of the cracks in the crack network module.

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