Deep coal seam high-pressure jet breaking physical fluidization mining simulation device and method

Abstract

The invention relates to a deep coal seam high-pressure jet breaking physical fluidization mining simulation device and a deep coal seam high-pressure jet breaking physical fluidization mining simulation method. The invention discloses a deep coal seam high-pressure jet breaking physical fluidization mining simulation device and method. The device comprises a triaxial pressurization experiment device; the hydraulic slotting experiment device is connected with the triaxial pressurization experiment device; the gas pressurization device is connected with the triaxial pressurization experiment device; and the three-phase reflux liquid conveying device is connected with the triaxial pressurization experiment device. The invention further provides a method for simulating co-mining of the high-pressure jet breaking physical fluidized coal and the coal bed gas in the deep coal seam by adopting the simulation device disclosed by the invention. According to the invention, the high-pressure jet breaking process of the deep coal seam with the depth of 1500-2500m and the simulation of the coal and coal bed gas co-mining process are accurately realized, so that the pressure relief and permeability increasing effects of the deep coal seam can be accurately evaluated, the mining efficiency of the coal seam and oil and gas resources is improved, and meanwhile, the loss of equipment is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of fluidized mining of deep coal seams, and in particular to a device and method for simulating high-pressure jet crushing physical fluidized mining of deep coal seams. Background Art

[0002] Coalbed methane is an important component of China's unconventional natural gas resources. It is estimated that the total amount of coalbed methane resources in my country shallower than 2000m is about 82 trillion cubic meters, of which the recoverable resources are 10 trillion cubic meters. With the increasing depletion of shallow coal resources in my country, the depth of underground mining has increased at a rate of 8 to 12 meters per year. According to incomplete statistics, the mining depth of more than 50 mines in my country has exceeded 1000 meters (some have been closed). Therefore, it is particularly necessary to study the mining methods of coal seams at depths of 1500m to 2000m.

[0003] As mining depth increases, the risks and challenges faced by deep-well mining are also increasing. Prominent coal and gas threats, soft rock support problems, ground pressure problems of small coal pillars on the goaf side, and ground temperature problems are becoming increasingly serious, and deep mining faces huge safety and technical challenges. As the gas pressure and gas content in deep coal seams gradually increase, the permeability of coal seams gradually decreases, resulting in increased difficulty in coal seam gas extraction. Specifically, it is manifested in low pre-extraction concentration and rapid attenuation of pre-extraction gas volume. It is well known that low permeability is the main factor affecting the effect of coal seam gas extraction and restricting safe production in coal mines. Therefore, improving the permeability of coal seams is the key to solving the problem of gas control.

[0004] In recent years, with the continuous development of coal mine gas control technology, a variety of gas permeability enhancement measures have been widely used in the control of gas disasters, mainly including hydraulic punching, hydraulic cutting, hydraulic fracturing, etc. Among them, hydraulic cutting technology uses high-pressure jet water as a medium to cut the coal sample in the borehole, thereby forming a new seam in the borehole to increase the permeability of the coal seam and reduce the stress of the original rock coal seam. However, the hydraulic cutting pressure is generally 30-60 MPa, which is suitable for medium-hard coal seams. The depth of the cutting is generally not more than 1 m. Therefore, when it is applied to deep coal seams with high ground stress and soft and broken coal seams, there is often a problem of frequent drill withdrawal during the construction process, which seriously affects the construction efficiency. At the same time, for the mining of deep underground coal seams, since the hydraulic cutting technology is not suitable for the soft and broken coal seams, and the seams generated by hydraulic cutting are also easy to close under high stress conditions, the coal seam and gas recovery rate are greatly reduced.

[0005] Although the mechanism and method of seam formation in coal seams have been studied in the prior art. For example, a hydraulic seam cutting device and seam cutting method that can realize abrasive recycling and seam cutting angle adjustment disclosed in the prior art can effectively avoid abrasive clogging of water tail caused by water tail siltation through abrasive recycling, while increasing the utilization rate of abrasives, and through the precise adjustment of the seam cutting angle, it can make full use of the characteristics of ground stress to cut wider and longer seams, thereby increasing the pressure relief effect of the seam under the same working conditions. Another example is a hydraulic seam cutting horizontal guide device and use method based on a gravity-guided mechanism, which uses a hollow drill rod inserted into the coal seam and a guide and seam cutter installed at the front end of the drill rod, and is associated with a gravity-guided ball to control a high-pressure water pipe, thereby ensuring that the seam cutting direction of the hydraulic seam cutting device is in the horizontal plane direction, and each borehole is hydraulically seamed in the horizontal direction, and finally forms an internal protective layer of the coal seam to effectively relieve pressure and increase permeability of the coal seam. However, the above methods all have the following problems: 1) It is impossible to simulate the triaxial geostress state of deep coal rock, and it is impossible to accurately obtain the hydraulic cutting pressure relief effect of deep stratum coal rock; 2) It is impossible to simulate the coupled influence of temperature field and stress field on deep stratum coal rock, and it is difficult to obtain accurate measurement results; 3) The cutting pressure relief method and experimental equipment are not suitable for the soft and broken coal seams in deep strata, and the cracks of conventional hydraulic cutting are easy to close under the action of high geostress, resulting in experimental failure, increasing equipment loss and reducing the mining efficiency of coal seams and oil and gas resources. Summary of the invention

[0006] The purpose of the present invention is to provide a deep coal seam high-pressure jet crushing physical fluidization mining simulation device and method, so as to accurately realize the simulation of the high-pressure jet crushing process of deep coal seams with a depth of 1500 to 2500m and the co-mining process of coal and coalbed methane, so as to accurately evaluate the pressure relief and permeability enhancement effect of deep coal seams, improve the mining efficiency of coal seams and oil and gas resources, and reduce equipment loss.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A deep coal seam high-pressure jet crushing physical fluidization mining simulation device, comprising: The triaxial pressure test device is used to simulate the pressure environment of deep underground coal and rock; A hydraulic cutting test device, connected to the triaxial pressurization test device, for simulating hydraulic cutting; A gas pressurizing device, connected to the triaxial pressurizing experimental device, for simulating the pore pressure provided by gas in deep underground coal and rock formations; The three-phase reflux liquid conveying device is connected to the triaxial pressurization experimental device and is used to simulate the separation of the solid-liquid-gas three-phase mixed reflux liquid.

[0008] According to the above technical means, a triaxial pressurization experimental device is set up to accurately simulate the complex pressure environment of deep underground coal and rock, providing real and reliable background conditions for the experiment. Through the introduction of hydraulic cutting experimental device, gas booster device and three-phase reflux fluid delivery device, the device can simulate multiple processes such as hydraulic cutting, gas pore pressure and separation of solid-liquid-gas three-phase mixed reflux fluid, meeting the full-scale research needs of deep coal seam co-mining. The device integrates multiple experimental functions into one, and can carry out multiple experiments at the same time, greatly improving the experimental efficiency. At the same time, the ingenious connection design between the devices facilitates experimental operation and maintenance. The device can not only be used for the study of deep coal seam co-mining, but also can be expanded to other related fields, such as underground resource development, geological disaster prediction, etc., and has broad application prospects.

[0009] Preferably, the triaxial pressure test device comprises: An experimental box, used to accommodate coal and rock specimens; A lifting hydraulic cylinder is arranged at the bottom of the experimental box and is used to provide axial pressure; A door-shaped reaction frame, arranged on the top of the experimental box, for providing an axial reaction force; A confining pressure pump is connected to the experimental box and is used to provide confining pressure.

[0010] By setting up an experimental box to accommodate coal and rock specimens, the closedness and safety of the experimental environment are ensured, so that the simulation device can simulate the real environment of deep underground coal and rock, and avoid the problem of errors in the simulation results caused by external environmental interference. The lifting hydraulic cylinder is set at the bottom of the experimental box, which can stably provide axial pressure to simulate the vertical pressure of coal and rock underground. The gate-shaped reaction force is set at the top of the experimental box, which effectively provides axial reaction force and cooperates with the lifting hydraulic cylinder to realize the pressure loading of the coal and rock specimens in the axial direction. The confining pressure pump is connected to the experimental box to provide confining pressure for the coal and rock specimens, simulating the lateral pressure of coal and rock underground. By adjusting the output pressure of the lifting hydraulic cylinder and the confining pressure pump, the axial pressure and confining pressure during the experiment can be accurately controlled, so as to simulate the stress state of coal and rock under different depths and geological conditions. This controllability makes the experimental results more accurate and reliable, which helps researchers to have a deep understanding of the mechanical properties and deformation and failure mechanisms of deep underground coal and rock. By rationally designing the simulation device, the connection between the components is tight and reliable, ensuring the safety and stability of the experimental process. At the same time, the experimental device is easy to operate and easy to use, which reduces the operating difficulty and labor intensity of the experimenters. In addition, the experimental device also has good maintainability and scalability, which is convenient for subsequent upgrades and improvements.

[0011] Preferably, the experimental box is provided with: A mounting hole, used for mounting the hydraulic slotting experimental device; An engine oil inlet, the engine oil inlet being connected to the confining pressure pump via a high-pressure oil pipe; A conductor inlet, wherein the conductor inlet is connected to a heating device through a conductor, and is used to simulate the high temperature state of deep underground coal and rock; The gas inlet is used for installing the gas boosting device.

[0012] Preferably, a mounting seat is further provided between the experimental box and the lifting hydraulic cylinder.

[0013] Preferably, the lifting hydraulic cylinder is connected to a hydraulic servo controller.

[0014] Preferably, the hydraulic cutting experimental device comprises: A casing, which penetrates through the mounting hole of the experimental box and extends into the wellhead of the coal and rock test piece; The oil pipe is arranged in the casing.

[0015] Preferably, one end of the oil pipe is connected to a rotary joint, a valve, a booster pump and a water tank in sequence.

[0016] Preferably, a tubing centralizer and a nozzle are installed on the tubing, and the nozzle is located below the tubing centralizer; A slide rail is installed on the inner wall of the sleeve, and the nozzle is in sliding cooperation with the slide rail.

[0017] By setting a rotating joint on the oil pipe, the oil pipe can rotate radially, and by setting a slide rail that slides with the nozzle, the oil pipe can move axially, realizing the simulation of the vertical mining of coal and coalbed methane in deep underground coal and rock, and realizing the full range of flexible adjustment of the oil pipe in the coal and rock specimen, thus ensuring that the high-pressure water jet can accurately act on the target area according to the simulation requirements, and improving the accuracy and efficiency of the simulated hydraulic cutting. This design not only enhances the adaptability and flexibility of the device, but also provides more accurate and reliable experimental conditions for simulating the physical fluidization mining of high-pressure jet crushing in deep coal seams.

[0018] Preferably, the three-phase reflux liquid conveying device comprises: A reflux liquid pipeline, one end of which is connected to the sleeve; A three-phase solid-liquid-gas separation device is connected to the other end of the reflux liquid pipeline.

[0019] Preferably, the three-phase solid-liquid-gas separation device comprises: a fairing, an exhaust pipe arranged in the fairing, and a reflector provided on the exhaust pipe and located in the fairing; a liquid discharge port and a solid discharge port are provided on the fairing, and a screen is installed at the liquid discharge port.

[0020] Preferably, the gas pressurizing device comprises: An upper pressure head, the upper pressure head is arranged at the gas inlet on the top of the experimental box; A downward pressure head, the downward pressure head is arranged at the gas inlet at the bottom of the experimental box; A flow guide tube, one end of which is connected to the high-pressure gas cylinder, and the other end of which is connected to the upper pressure head and / or the lower pressure head.

[0021] By setting the upper and lower pressure heads, gas pressurization can be performed at the top and bottom of the experimental box at the same time, which improves the efficiency and uniformity of gas pressurization. At the same time, the connection design of the guide tube enables the gas in the high-pressure gas cylinder to flow smoothly into the upper and / or lower pressure heads, further improving the pressurization effect. Due to the joint action of the upper and lower pressure heads, and the precise guidance of the guide tube, the device can achieve rapid and efficient pressurization of the gas in the coal and rock specimens in the experimental box, thereby accurately simulating the pore pressure of deep underground coal and rock. The structural design of the device is concise and clear, and the operation process is simple and easy to understand. The experimenter only needs to connect the high-pressure gas cylinder to the upper and / or lower pressure heads through the guide tube to achieve the gas pressurization operation, which greatly reduces the difficulty and complexity of the operation. The gas pressurization device is suitable for a variety of experimental scenarios and experimental needs, and can meet the requirements of different experiments for gas pressure. At the same time, its structural design is flexible and variable, and can be adaptively adjusted according to specific experimental needs. The operation process of the device is simple and safe, and can effectively avoid safety hazards during the experiment.

[0022] Preferably, the depth of the deep underground coal rock is 1500 to 2500 meters.

[0023] Preferably, the simulation device can provide a confining pressure of 60 MPa, a temperature of 120° C. and a pore pressure of 30 MPa.

[0024] Preferably, the wellbore of the simulation device can withstand a pressure of 80 MPa, and the wellhead can withstand a pressure of 100 MPa.

[0025] The present invention also provides a method for simulating the physical fluidization of coal and coalbed methane co-mining in deep coal seams by using the simulation device of the present invention, comprising the following steps: The coal and rock specimens are placed in an experimental box of a triaxial pressure test device, and axial pressure, axial reaction force and confining pressure are applied to the coal and rock specimens by the triaxial pressure test device to simulate the triaxial pressure of deep underground coal and rock. Pore pressure is applied to the coal and rock specimens by a gas booster device to simulate the pore pressure of deep underground coal and rock. The coal and rock specimens are cut by a hydraulic cutting test device to simulate hydraulic cutting. The fluidized liquid mixture obtained by cutting flows into a three-phase reflux liquid conveying device through a casing of the triaxial pressure test device, and the fluidized liquid mixture is separated by the three-phase reflux liquid conveying device to simulate the separation of solid-liquid-gas three-phase mixed reflux liquid.

[0026] The present invention applies axial pressure, axial reaction force and confining pressure to the coal rock specimen by cleverly designing a triaxial pressurization test device, and applies pore pressure through a gas booster device, which can accurately simulate the complex pressure environment of deep underground coal and rock, thereby improving the accuracy and reliability of the simulation experiment. By setting up a hydraulic cutting test device to cut the coal rock specimen, the hydraulic cutting process in the actual mining process can be simulated, which is helpful to study the influence of hydraulic cutting on coal rock crushing and coalbed methane release. By setting up a three-phase mixed reflux liquid separation device, the fluid liquid mixture obtained by cutting flows into the three-phase reflux liquid conveying device through the casing of the triaxial pressurization test device, and is separated by the device, which can simulate the processing process of the solid-liquid-gas three-phase mixed reflux liquid in the actual mining process, which is helpful to study the composition and properties of the reflux liquid, and provide an important basis for the co-mining of coalbed methane and coal. The present invention combines a simulation device with a method for co-mining of coal and coalbed methane by physical fluidization of high-pressure jet crushing in deep coal seams, and proposes a new experimental method, which provides new ideas and technical means for research in related fields. It can be widely used in research on co-mining of coalbed methane and coal, as well as related geology, mining, energy and other fields, and has important practical value and application prospects.

[0027] Beneficial effects of the present invention: The deep coal seam high-pressure jet crushing physical fluidization mining simulation device of the present invention, by setting up a triaxial pressurization experimental device, can accurately simulate the complex pressure environment of deep underground coal and rock, and provide real and reliable background conditions for the simulation experiment; through the introduction of a hydraulic cutting experimental device, a gas pressurization device and a three-phase reflux liquid conveying device, the device can simulate multiple processes such as hydraulic cutting, gas pore pressure and separation of solid-liquid-gas three-phase mixed reflux liquid, meeting the comprehensive research needs for deep coal seam co-mining. The device integrates multiple experimental functions into one, and can carry out multiple simulation experiments at the same time, which greatly improves the authenticity and comprehensiveness of simulating the actual co-mining of coal and coalbed methane, and improves the efficiency of the simulation experiment. At the same time, the ingenious connection design between the devices facilitates experimental operation and maintenance. The device can not only be used for the research of deep coal seam co-mining, but also can be expanded to other related fields, such as underground resource development, geological disaster prediction, etc., and has broad application prospects.

[0028] The deep coal seam high-pressure jet crushing physical fluidized mining simulation device of the present invention can be used to simulate the coal and coalbed methane storage environment at a depth of 1500 to 2500 meters, and to conduct a high-pressure water jet cutting and cavitation physical fluidized mining simulation experiment. By cleverly setting up a triaxial pressurization experimental device to apply pressure in the axial and radial directions, the radial confining pressure can be provided to 60Mpa by the confining pressure pump, and a gas pressurization device is also designed to apply gas pore pressure to the coal rock, up to 30MPa. The temperature heating device heats the oil around the coal rock sample to continuously increase the temperature, simulating the actual high-temperature environment deep underground. At the same time, in order to enhance the hydraulic cutting and pressure relief effect of deep underground coal and rock, the oil pipe is designed to be able to move axially and rotate radially to drive the movement of the nozzle, thereby achieving a better cutting and pressure relief effect. A cavity can be created on the coal seam, so that the coal and coalbed methane crushed by the hydraulic jet can flow out of the wellbore with the fluid, effectively realizing the fluidized mining of simulated deep coal resources, and a three-phase solid-liquid separator is designed directly at the wellhead to directly separate different mineral resources, which greatly improves the mining efficiency. It has promotion and application value in the field of fluidized mining technology of deep coal seams. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of a deep coal seam high-pressure jet crushing physical fluidization mining simulation device and method; Figure 2 It is a partial view of the assembly of the experimental box and the coal and rock specimens; Figure 3 A partial view of the assembly for the casing, tubing, nozzle, slide rail, and pressure strain gauge; Figure 4 It is a partial view of the wellhead structure; Figure 5 A partial view of the simulated tubing string structure; Among them, 1-coal and rock specimen, 101-hollow cavity; 2-experimental box, 201-mounting hole, 202-oil inlet, 203-wire inlet, 204-gas inlet, 205-lower box, 206-cover plate; 3-lifting hydraulic cylinder; 4-door-shaped reaction frame; 5-confining pressure pump; 6-high-pressure oil pipe; 7-heating device; 8-mounting seat; 9-hydraulic servo controller; 10-casing; 11-oil pipe; 12-swivel joint; 13-valve; 14- Booster pump; 15-water tank; 16-oil pipe centralizer; 17-nozzle; 18-slide rail; 19-reflux liquid pipeline; 20-upper pressure head; 21-lower pressure head; 22-flow guide pipe; 23-high-pressure gas cylinder; 24-pressure test valve; 25-pressure gauge; 26-pressure strain gauge; 27-flow monitor; 28-fairing, 281-liquid discharge port, 282-solid discharge port; 29-exhaust pipe; 30-reflector plate; 31-screen; 32-pressure reducing valve; 33-pad. DETAILED DESCRIPTION

[0030] The following will describe the embodiments of the present invention with reference to the preferred embodiments, and those skilled in the art can clearly understand other advantages and effects of the present invention from the contents described in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention, not for limiting the scope of protection of the present invention. Example

[0031] like Figures 1 to 5 As shown, a deep coal seam high-pressure jet crushing physical fluidization mining simulation device and method, comprising: The triaxial pressure test device is used to simulate the pressure environment of deep underground coal and rock; A hydraulic cutting test device, connected to the triaxial pressurization test device, for simulating hydraulic cutting; A gas pressurizing device, connected to the triaxial pressurizing experimental device, for simulating the pore pressure provided by gas in deep underground coal and rock formations; The three-phase reflux liquid conveying device is connected to the triaxial pressurization experimental device and is used to simulate the separation of the solid-liquid-gas three-phase mixed reflux liquid.

[0032] In some embodiments, the triaxial compression test apparatus comprises: The experimental box 2 is used to accommodate the coal and rock specimens 1; A lifting hydraulic cylinder 3 is provided at the bottom of the experimental box 2 and is used to provide axial pressure; The gate-shaped reaction frame 4 is arranged on the top of the experimental box 2 and is used to provide an axial reaction force. The gate-shaped reaction frame 4 is connected to the ground, and the crossbeam of the gate-shaped reaction frame 4 is in contact with the experimental box 2 through the pad 33; The confining pressure pump 5 is connected to the experimental box 2 and is used to provide confining pressure.

[0033] During the simulation experiment, the jacking hydraulic cylinder 3 provides power, and two pads 33 with a height of 10 mm and a gate-shaped reaction frame 4 provide axial reaction force. The pads 33 can provide supporting reaction force to prevent damage to the coal rock specimen 1 or the device due to excessive axial pressure. The pressure is controlled by the hydraulic servo controller 9 to ensure that the lifting rate of the jacking hydraulic cylinder 3 remains constant.

[0034] Exemplarily, the installation box 2 includes a lower box 205 and a cover plate 206 installed on the lower box 205. The lower box 205 and the cover plate 206 are assembled and fixed together by bolts.

[0035] In some embodiments, the experimental box 2 is provided with: The mounting hole 201 is used to install the hydraulic cutting experimental device; The oil inlet 202 is connected to the confining pressure pump 5 through the high-pressure oil pipe 6, and the confining pressure pump 5 injects oil into the lower box 205 to provide oil pressure. The pressure and the pressurization rate are controlled by the servo controller, and the maximum confining pressure can be 60MPa. The wire inlet 203 is connected to the heating device 7 through a wire to simulate the high temperature state of deep underground coal and rock; Gas inlet 204, used to install a gas booster device; A mounting seat 8 is also provided between the experimental box 2 and the lifting hydraulic cylinder 3, and the lifting hydraulic cylinder 3 provides power for vertical movement of the mounting seat 8; The lifting hydraulic cylinder 3 is connected to the hydraulic servo controller 9 .

[0036] Among them, oil is injected into the experimental box 2 through the confining pressure pump 5 to provide oil pressure, and the pressure size and pressurization rate are controlled by the servo controller. The maximum confining pressure of 60MPa can be provided. The jacking hydraulic cylinder 3 provides vertical movement power to the mounting seat 8, and the gate-shaped reaction frame 7 provides axial reaction force, thereby simulating the triaxial stress state of deep underground coal and rock.

[0037] In some embodiments, the hydraulic cutting experimental device includes: The casing 10 penetrates through the mounting hole 201 of the experimental box 2 and extends into the wellhead of the coal-rock specimen 1; The oil pipe 11 is arranged in the casing 10 .

[0038] Exemplarily, the mounting hole 201 is provided on the cover plate 206, and the oil pipe 11 is sleeved in the casing 10 and then penetrated through the mounting hole 201. The casing 10 is fixed to the mounting hole 201 by bolts, and a pressure test valve 24 is installed on the oil pipe 11 near the mounting hole 201.

[0039] The oil inlet 202 is arranged on the side wall of the lower box 205. One end of the high-pressure oil pipe 6 is inserted into the oil inlet 202, and the other end is connected to the confining pressure pump 5. After the connection is completed, the hole is sealed with strong glue to ensure that the internal environment of the experimental box 2 is closed.

[0040] The wire inlet 203 is arranged on the side wall of the lower box 205. The wire inlet 203 is connected to the heating device 7 through a wire. The engine oil is heated by the heating device 7, and the temperature can reach 120°C to simulate the high temperature state of deep underground coal rock. After the connection is completed, the hole is sealed with strong glue to ensure that the internal environment of the experimental box 2 is closed.

[0041] In the actual simulation experiment, a hole is drilled on the top of the coal rock specimen 1 to simulate the wellhead. The inner diameter of the wellhead is designed to be 30-50 mm. The casing 10 is inserted from the wellhead, and concrete is used to cement the well to stabilize the casing 10. The oil pipe 11 is inserted into the middle of the casing 10. The oil pipe 11 is connected to the wellhead surface device, which specifically includes: a rotary joint 12, a valve 13, a pressure gauge 25, a booster pump 14 and a water tank 15 connected in sequence. Among them, the oil pipe 11 can transport high-pressure water, and the water in the water tank 15 is provided with pressure by the booster pump 14, which has a high-pressure jet effect, and is transported through the oil pipe 11 and ejected by the nozzle 17. The pressurization of the booster pump 14 can be adjusted, and the value is displayed on the pressure gauge 25. The valve 13 can adjust the high-pressure water flow rate to achieve a suitable jet hydraulic force. The space where the casing 10 extends into the experimental box 2 is controlled by a valve to ensure that the space in the experimental box 2 is airtight. The middle part of the oil pipe 11 is also controlled by a pressure test valve 24, which can adjust the amount of high-pressure water in the oil pipe 11 and ensure that there is no leakage in the access space. A pipe straightener 16 is installed on the upper part of the nozzle 17 to fix the oil pipe 11 in the middle of the casing 10 so that it will not deviate due to the recoil force after the nozzle 17 ejects the high-pressure water. The nozzle 17 is aimed at the cavity for cutting, and a good cutting effect is obtained. The high-pressure water is transported to the nozzle 17 through the oil pipe 11 and then ejected. The coal rock specimen 1 is cut to relieve pressure to form a hollow cavity 101. In order to improve the cutting effect in deep formation environments, a slide rail 18 is designed to be installed on the edge of the wall of the casing 10. The nozzle 17 moves up and down by controlling the movement of the oil pipe 11. The nozzle 17 is consistent with the size of the slide rail 18 and can be stuck on the slide rail 18 to make a reciprocating motion to cut. The cutting effect is shown in the figure. Figure 3 . In conjunction with the moving slitting of the nozzle 17, a series of axial slits should be reserved on the wall of the casing 10, and high-pressure water can be used to cut and relieve pressure along the slits. After the high-pressure water slitting and pressure relief, a hollow cavity 101 is created inside the coal rock specimen 1, and the jet continues to disperse the internal coal seam and coalbed methane. Due to the water pressure, the pressure inside the oil pipe 11 is greater than that of the casing 10 and the hollow cavity 101. The gas-liquid-solid mixture formed after the hydraulic jet will return to the annular section of the casing 10 under the action of the pressure difference and flow toward the wellhead.

[0042] In some embodiments, one end of the oil pipe 11 is connected to a rotary joint 12, a valve 13, a booster pump 14 and a water tank 15 in sequence, and a pressure gauge 25 is installed on the pipeline between the valve 13 and the booster pump 14; An oil pipe centralizer 16 is installed on the oil pipe 11. A nozzle 17 is provided on the oil pipe 11. The nozzle 17 is located below the oil pipe centralizer 16. A pressure strain gauge 26 is provided at the nozzle 17. A slide rail 18 is installed on the inner wall of the sleeve 10, and the nozzle 17 and the slide rail 18 are in sliding fit.

[0043] A rotary joint 12 is provided on the oil pipe 11, so that the oil pipe 11 can rotate radially, and a slide rail that is slidably matched with the nozzle 17 is provided, so that the oil pipe 11 can move axially. Therefore, the hydraulic cutting can realize the axial movement and radial rotation of the oil pipe 11 through the slide rail 18 and the rotary joint 12 with the help of mechanical external force, drive the nozzle 17 to move or slide, and realize the full cutting and pressure relief of the coal rock specimen 1, so as to realize the full extraction of coal and coalbed methane and the fluidized integrated extraction along the annulus of the casing 10.

[0044] Among them, the design of the rotary joint 12 enables the oil pipe 11 to rotate radially, and the direction and position of the oil pipe 11 can be flexibly adjusted. In actual coal seam mining, the geological conditions of the coal seam are complex and changeable. Therefore, during the simulation test, the rotary joint 12 is designed to adjust the oil pipe 11 according to the direction and shape of the coal seam, better simulate the actual situation of the coal seam, improve the accuracy of the simulation, and provide more favorable technical support for actual coal seam mining. In addition, the reasonable design and use of the rotary joint 12 can reduce the wear of the oil pipe 11 during the rotation process and extend the service life of the simulation device.

[0045] The sliding fit design of the slide rail 18 and the nozzle 17 enables the oil pipe 11 to move axially, so as to simulate the coal seam mining process and accurately control the axial position of the oil pipe as needed, thereby realizing accurate positioning and control of the mining area. At the same time, the use of the slide rail 18 can reduce the friction of the oil pipe 11 during the axial movement. In addition, the axial movement function of the slide rail 18 can be combined with the automatic control system to realize automatic control and adjustment of the position of the oil pipe 11.

[0046] In the actual simulation experiment, a hole is drilled on the top of the coal rock specimen 1 to simulate the wellhead, and the casing 10 is inserted from the wellhead. After cementing, the oil pipe 11 is inserted into the middle of the casing 10, and the oil pipe 11 is connected to the wellhead surface device, which includes a rotary joint 12, a valve 13, a pressure gauge 25, a booster pump 14 and a water tank 15. At the same time, the oil pipe centralizer 16 is installed on the oil pipe 11 above the nozzle 17, so that the oil pipe 11 is fixed in the middle of the casing 10 to ensure the subsequent hydraulic fracturing effect.

[0047] Among them, axial movement means that the oil pipe 11 moves in the axial direction, driving the nozzle 17 to move in the slide rail 18, and an axial slot perpendicular to the cross section of the casing 10 is reserved on the casing 10. The high-pressure water flow ejected by the nozzle 17 passes through the slot reserved on the casing 10 to cut and relieve pressure on the coal rock specimen 1, forming a hollow cavity 101. Radial rotation means that the oil pipe 11 rotates at a certain angle through the rotary joint 12, and a slot parallel to the cross section of the casing 10 is reserved on the casing 10. The high-pressure water flow ejected by the nozzle 17 passes through the slot reserved on the casing 10 to cut and relieve pressure on the coal rock.

[0048] In some embodiments, the three-phase reflux fluid delivery device comprises: A reflux liquid pipeline 19, one end of which is connected to the sleeve 10, and a flow monitor 27 is installed on the reflux liquid pipeline 19, so that the solid-liquid-gas three-phase mixed reflux liquid in the reflux liquid pipeline 19 is monitored in real time by the flow monitor 27, and the real-time flow of the liquid phase and the gas phase in the reflux liquid is obtained for subsequent separation work; A three-phase solid-liquid-gas separation device is connected to the other end of the reflux liquid pipeline 19 .

[0049] Exemplarily, the three-phase solid-liquid-gas separation device includes a fairing 28, an exhaust pipe 29 arranged in the fairing 28, and a reflector 30 arranged on the exhaust pipe 29 and located in the fairing 28; the fairing 28 is provided with a liquid discharge port 281 and a solid discharge port 282, and a screen 31 is installed at the liquid discharge port 281.

[0050] In the actual simulation experiment, the solid-liquid-gas three-phase mixed reflux liquid flows along the annulus of the casing 10 under the action of the pressure difference, flows through the valve and the reflux liquid pipeline 19, and then enters the three-phase solid-liquid-gas separation device, and then separates the mineral resources through the three-phase solid-liquid-gas separation device. Specifically, the fairing 28 in the three-phase solid-liquid-gas separation device will rectify the gas-liquid-solid mixture entering the three-phase solid-liquid-gas separation device, and the fairing 28 rotates to perform centrifugal motion, generating a large centrifugal force to separate the liquid and solid mixture from the gas. The centrifugal force of the liquid and solid mixture is different from that of the gas. After the gas rotates at the top of the separator, it enters the exhaust pipe 29 in the center of the fairing 28 due to the accumulation pressure difference and is discharged through the exhaust pipe 29; the liquid and solid mixture has a large centrifugal force, and is adsorbed on the wall of the separator and then flows down to the drain port 271. The liquid contains a solid coal slag mixture, and the filtration effect of the screen 31 can divert the liquid, while the solid accumulates at the solid discharge port 272. A reflector 30 is installed in the middle of the exhaust pipe 29 to make the gas volume accumulate and expand upward, thereby preventing the gas from diffusing and overflowing from the liquid phase outlet. The flow monitor 27 can monitor the ratio of the gas phase and the solid phase and the corresponding flow rate in the solid-liquid-gas three-phase mixed reflux liquid in real time, and the separation of resources can be achieved through the solid-liquid separator, which is beneficial to purification and extraction.

[0051] In some embodiments, the gas pressurizing device comprises: An upper pressure head 20, which is disposed at the gas inlet 204 at the top of the experimental box 2; A pressure head 21, which is disposed at the gas inlet 204 at the bottom of the experimental box 2; The flow guide pipe 22 has one end connected to the high-pressure gas cylinder 23 and the other end connected to the upper pressure head 20 and / or the lower pressure head 21 . The flow guide pipe 22 is also provided with a pressure reducing valve 32 .

[0052] The gas booster device provides the coal rock specimen 1 with a pore pressure of up to 30 MPa. When injecting gas, it ensures that the pressure is increased synchronously with the oil pressure, thereby simulating the complex stress conditions of the underground rock formation and ensuring the authenticity of the simulation process. The pressure is controlled by the pressure reducing valve 32 and real-time data is displayed on the pressure gauge. After the test, the gas is discharged from the lower pressure head 21 due to the pressure difference, and the exhaust gas remains in the high-pressure gas cylinder 23 connected to the lower pressure head 21.

[0053] Exemplarily, the gas inlet 204 at the top of the experimental box 2 is arranged on the cover 206, and an upper pressure head 20 is provided in the gas inlet 204 on the cover 206. The gas inlet 204 at the bottom of the experimental box 2 is arranged at the bottom of the lower box 205, and a lower pressure head 21 is provided in the gas inlet 204 at the bottom of the lower box 205. After the upper pressure head 20 and the lower pressure head 21 are installed, they are sealed with strong glue to ensure a high-pressure closed environment inside the experimental box.

[0054] In some embodiments, the depth of the deep underground coal rock is 1500 to 2500 meters.

[0055] In some embodiments, the experimental apparatus can provide a confining pressure of 60 MPa, a temperature of 120°C, and a pore pressure of 30 MPa; In some embodiments, the wellbore of the experimental device can withstand a pressure of 80 MPa, and the wellhead can withstand a pressure of 100 MPa.

[0056] In some embodiments, a method for simulating the physical fluidization of coal and coalbed methane co-mining in deep coal seams by using the simulation experimental device in any of the above embodiments is also provided, comprising the following steps: The coal and rock specimens are placed in an experimental box of a triaxial pressure test device, and axial pressure, axial reaction force and confining pressure are applied to the coal and rock specimens through the triaxial pressure test device. Pore pressure is applied to the coal and rock specimens through a gas booster device to simulate the pressure environment of deep underground coal and rock. The coal and rock specimens are cut through a hydraulic cutting test device to simulate hydraulic cutting. The fluidized liquid mixture obtained by cutting flows into a three-phase reflux liquid conveying device through a casing of the triaxial pressure test device. The fluidized liquid mixture is separated through the three-phase reflux liquid conveying device to simulate the separation of solid-liquid-gas three-phase mixed reflux liquid.

[0057] Exemplarily, a method for co-mining coal and coalbed methane by simulating high-pressure jet crushing physical fluidization of deep coal seams using the simulation experimental device in any of the above embodiments includes the following steps: S1. Prepare coal rock specimen 1, and drill a hole on the top of the coal rock specimen 1 to simulate the wellhead. The diameter of the hole is about 50 mm, and a layer of polyurethane sealant with a thickness of about 1 mm is evenly applied on the outer surface of the coal sample specimen 1. The dimensions of the coal rock specimen 1 used in this experiment are 300.00 mm in length direction (i.e. X-axis direction), 300.00 mm in width direction (i.e. Y-axis direction), and 300.00 mm in height direction (i.e. Z-axis direction).

[0058] S2. Place the coal-rock specimen 1 processed in S1 and the engine oil for heating in the lower box 205 of the triaxial pressurization test device, and fix the lower box 205 to the mounting seat 8; fix the mounting seat 8 on the lifting hydraulic cylinder 3, and connect the lifting hydraulic cylinder 3 to the hydraulic servo controller 9 to control the pressure of the lifting hydraulic cylinder 3 through the hydraulic servo controller 9; install a high-pressure oil pipe 6 at the engine oil inlet 202, and connect the high-pressure oil pipe 6 to the confining pressure pump 5, and the diameter of the engine oil inlet 202 is about 2 cm; insert a wire at the wire inlet 203, and connect the wire to the heating device 7, heat the engine oil through the heating device 7 to simulate the high temperature state of coal and rock deep underground, and seal the hole with strong glue after the connection is completed to ensure that the internal environment of the experimental box 2 is closed. Among them, the lower box 205 is made of a 25mm thick steel plate, which can withstand 60MPa confining pressure and 30MPa pore pressure. The inner diameter of the simulated wellbore is 30-50mm and the pressure is 80MPa; the simulated wellhead (double): the pressure is 100MPa.

[0059] S3. Pre-install a slide rail 18 and a pressure strain gauge 26 on the inner wall surface of the casing 10 of the hydraulic slotting experimental device, and inject concrete into the casing 10 to simulate the wellbore cementing measures, and then pass the casing through the mounting hole 201 of the cover plate 206 and consolidate it in the middle of the wellhead of the coal rock specimen 1; pre-install multiple nozzles 17 and tubing centralizers 16 at intervals on the oil pipe 11 with a diameter of about 20 mm, and the oil pipe centralizer 16 is located above the nozzle 17, and then insert the oil pipe 11 into the middle of the casing 10 and consolidate it, and the oil pipe centralizer 16 can keep the oil pipe 11 in the middle of the casing 10 and will not be offset due to the recoil force of the high-pressure water.

[0060] S4. Extend and connect a high-pressure pipe to the annulus of the casing 10 at the wellhead as a reflux pipeline 19, install a flow monitor 27 on the reflux pipeline 19, and connect the other end of the reflux pipeline 19 to a three-phase solid-liquid-gas separation device; set the upper pressure head 20 of the gas booster in the gas inlet 204 on the cover plate 206, and the lower pressure head 21 in the gas inlet 204 at the bottom of the lower box 205; the upper pressure head 20 and the lower pressure head 21 are respectively connected to one end of the guide tube 22, and the other end of the guide tube 22 is connected to the high-pressure gas cylinder 23. At the same time, a pressure gauge and a pressure reducing valve 32 are provided on the guide tube 22. After installation, a strong glue is used to seal it to ensure a high-pressure closed environment inside the experimental box. After the test, the exhaust gas flows through the guide tube 22 through the lower pressure head 21 due to the pressure difference and is finally stored in the high-pressure gas cylinder 23 connected to the lower pressure head 21.

[0061] S5. Connect the rotary joint 12, valve 13, pressure gauge 25, booster pump 14 and water tank 15 in sequence at the end of the oil pipe 11 located at the wellhead. The high-pressure water for hydraulic slitting comes from the booster pump 14 to provide pressure. Install the pressure test valve 24 on the oil pipe 11 to control the flow in the oil pipe 11. After the wellhead is connected externally, cover the cover plate 206 on the top of the lower box 205 to check the air tightness. Bolts are used to connect and fix the cover plate 206 to the lower box 205 to ensure that all valves are in a closed state, and check the air tightness of each interface to ensure that there is no water or oil leakage.

[0062] S6. Fix two pads 33 on the cover plate 206, and then install a gate-shaped reaction frame 4 on the pads 33. The supporting bracket of the gate-shaped reaction frame 4 is set on the ground to support the entire device; connect the components for collecting temperature and pressure to the data acquisition unit, and then connect the wiring of the control unit and the data acquisition unit, check whether the data acquisition unit is operating normally, and use a vacuum pump to evacuate each pipeline in the experimental device.

[0063] S7. Set the loading pressure and loading rate of the experimental device through the computer and hydraulic servo controller 9, and set the pressure to the specified value through the confining pressure pump 5. At the same time, turn on the gas pressurizing device, and set the specified gas pressure to simulate the pore pressure through the pressure reducing valve 32; turn on the heating device 7 to heat the oil around the coal rock specimen 1 to a preset temperature; apply the axial pressure, confining pressure and pore pressure simultaneously, and control the specific pressure by operating the computer and the confining pressure pump, and finally stabilize at the set value.

[0064] S8, open valve 13, and the water in water tank 15 is pressurized into high-pressure water by booster pump 14, and the pressure is adjusted by pressure gauge 25 on oil pipe 11; after adjusting to the appropriate pressure, open pressure test valve 33, water flows into coal rock specimen 1, and is ejected from nozzle 17 to cut coal rock specimen 1. The oil pipe 11 is dragged by mechanical external force, so that nozzle 17 on oil pipe 11 moves back and forth in the groove of slide rail 18, and coal rock specimen 1 is cut from the slot reserved in casing 10; hydraulic jet cutting continues, and a hollow cavity 101 is formed in coal rock specimen 1, in which coal and coalbed methane form a fluid liquid mixture under the action of jet, and the pressure near the wellbore is recorded by pressure strain gauge 26 during the jet process.

[0065] S9. High-pressure water flows in the hollow cavity 101 and the oil pipe 11 of the coal-rock specimen 1, and the pressure is greater than that of the annulus of the casing 10, so that the fluid mixture impacted by the jet in the hollow cavity 101 flows toward the casing 10 due to the pressure difference, and flows toward the wellhead; the valve is opened to allow the fluid mixture to flow through the reflux liquid pipeline 19, and the flow rate of the gas and liquid phases in the fluid mixture is detected in real time by the flow monitor 27, and then the fluid mixture flows to the three-phase solid-liquid-gas separation device; the three-phase solid-liquid-gas separation device operates continuously, and the fluid mixture undergoes centrifugal motion after entering, and the gas and liquid can be separated due to the different centrifugal forces of different phases, and finally the coal particle solids and fluids are filtered through the screen 31 to achieve the purpose of diversion.

[0066] S10. When the value change of the pressure strain gauge 26 is no longer obvious, it indicates that the hollow cavity 101 has been hydraulically cut, and the pressure can be relieved and the equipment can be taken out for the next set of experiments. Nozzles can be installed on both sides of a coal rock sample 1 for jetting. Through the radial rotation and axial movement of the oil pipe 11, a better hydraulic cutting effect can be achieved to maximize the utilization of coal resources and the exploitation of underground resources. After the experiment, the corresponding oil pipes and casings are cleaned, and the data is recorded. The cavity-making effect of the hydraulic cutting of coal rocks is photographed and recorded, and the extracted coalbed methane and coal and other resources are collected.

[0067] In summary, the deep coal seam high-pressure jet crushing physical fluidization mining simulation device of the present invention, by setting up a triaxial pressurization experimental device, can accurately simulate the complex pressure environment of deep underground coal and rock, and provide real and reliable background conditions for the simulation experiment; through the introduction of a hydraulic cutting experimental device, a gas pressurization device and a three-phase reflux liquid conveying device, the device can simulate multiple processes such as hydraulic cutting, gas pore pressure and separation of solid-liquid-gas three-phase mixed reflux liquid, meeting the comprehensive research needs for deep coal seam co-mining. The device integrates multiple experimental functions into one, and can carry out multiple simulation experiments at the same time, which greatly improves the authenticity and comprehensiveness of simulating the actual co-mining of coal and coalbed methane, and improves the efficiency of the simulation experiment. At the same time, the ingenious connection design between the devices facilitates experimental operation and maintenance. The device can not only be used for the research of deep coal seam co-mining, but also can be expanded to other related fields, such as underground resource development, geological disaster prediction, etc., and has broad application prospects.

[0068] The deep coal seam high-pressure jet crushing physical fluidized mining simulation device of the present invention can be used to simulate the coal and coalbed methane storage environment at a depth of 1500 to 2500 meters, and to conduct high-pressure water jet slitting and cavitation physical fluidized mining simulation experiments. The triaxial pressurization experimental device provided by the present invention can apply pressure in the axial and radial directions. The radial confining pressure can be provided to 60Mpa by the confining pressure pump. The gas pressurization device is also designed to apply gas pore pressure to the coal rock, which can reach up to 30MPa. The temperature heating device heats the oil around the sample to continuously increase the temperature, simulating the actual high-temperature environment deep underground. In order to enhance the hydraulic cutting and pressure relief effect in deep formations, the present invention proposes that the nozzle can be driven to move through the axial movement and radial rotation of the oil pipe, so as to achieve a better cutting and pressure relief effect, and a cavity can be created on the coal seam, so that the coal and coalbed methane crushed by the hydraulic jet can flow out of the wellbore with the fluid, thereby realizing the simulation of fluidized mining of deep coal resources, and designing a three-phase solid-liquid separator at the wellhead to separate different mineral resources. In the field of fluidized mining technology of deep coal seams, it has a value of promotion and application.

[0069] The present invention applies axial pressure, axial reaction force and confining pressure to the coal rock specimen by cleverly designing a triaxial pressurization test device, and applies pore pressure through a gas booster device, which can accurately simulate the complex pressure environment of deep underground coal and rock, thereby improving the accuracy and reliability of the simulation experiment. By setting up a hydraulic slitting test device to cut the coal rock specimen, the hydraulic slitting process in the actual mining process can be simulated, which is helpful to study the influence of hydraulic slitting on coal rock crushing and coalbed methane release. By setting up a three-phase mixed reflux liquid separation device, the fluid liquid mixture obtained by cutting flows into the three-phase reflux liquid conveying device through the casing of the triaxial pressurization test device, and is separated by the device, which can simulate the processing process of the solid-liquid-gas three-phase mixed reflux liquid in the actual mining process, which is helpful to study the composition and properties of the reflux liquid, and provide an important basis for the co-mining of coalbed methane and coal. The present invention combines a simulation device with a method for co-mining of coal and coalbed methane by physical fluidization of high-pressure jet crushing in deep coal seams, and proposes a new experimental method, which provides new ideas and technical means for research in related fields. It can be widely used in research on co-mining of coalbed methane and coal, as well as related geology, mining, energy and other fields, and has important practical value and application prospects.

[0070] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or change made by a person skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A deep coal seam high-pressure jet crushing physical fluidization mining simulation device, characterized in that: include: The triaxial pressure test device is used to simulate the pressure environment of deep underground coal and rock; A hydraulic cutting test device, connected to the triaxial pressurization test device, for simulating hydraulic cutting; A gas pressurizing device, connected to the triaxial pressurizing experimental device, for simulating the pore pressure provided by gas in deep underground coal and rock formations; The three-phase reflux liquid conveying device is connected to the triaxial pressurization experimental device and is used to simulate the separation of the solid-liquid-gas three-phase mixed reflux liquid.

2. The deep coal seam high pressure jet crushing physical fluidization mining simulation device according to claim 1 is characterized in that: The triaxial pressure test device comprises: An experimental box (2) for accommodating the coal and rock test pieces (1); A lifting hydraulic cylinder (3) is arranged at the bottom of the experimental box (2) and is used to provide axial pressure; A door-shaped reaction frame (4), arranged on the top of the experimental box (2), and used for providing an axial reaction force; A confining pressure pump (5) is connected to the experimental box (2) and is used to provide confining pressure.

3. The deep coal seam high pressure jet crushing physical fluidization mining simulation device and method according to claim 2 is characterized in that: The experimental box (2) is provided with: A mounting hole (201) for mounting the hydraulic slotting experimental device; An engine oil inlet (202), the engine oil inlet (202) being connected to the confining pressure pump (5) via a high-pressure oil pipe (6); A wire inlet (203), the wire inlet (203) being connected to a heating device (7) via a wire, and being used to simulate a high temperature state of coal rock deep underground; A gas inlet (204) for installing the gas pressurizing device; And / or, a mounting seat (8) is further provided between the experimental box (2) and the lifting hydraulic cylinder (3); And / or, the lifting hydraulic cylinder (3) is connected to a hydraulic servo controller (9).

4. The deep coal seam high pressure jet crushing physical fluidization mining simulation device according to claim 2 is characterized in that: The hydraulic cutting experimental device comprises: A casing (10) is inserted into a mounting hole (201) of the experimental box (2) and extends into a wellhead of the coal-rock test piece (1); An oil pipe (11) is arranged in the casing (10).

5. The deep coal seam high pressure jet crushing physical fluidization mining simulation device according to claim 4 is characterized in that: One end of the oil pipe (11) is connected in sequence to a rotary joint (12), a valve (13), a booster pump (14) and a water tank (15); And / or, a tubing centralizer (16) and a nozzle (17) are installed on the tubing (11), and the nozzle (17) is located below the tubing centralizer (16); A slide rail (18) is installed on the inner wall of the sleeve (10), and the nozzle (17) and the slide rail (18) are in sliding cooperation.

6. The deep coal seam high pressure jet crushing physical fluidization mining simulation device according to claim 4 is characterized in that: The three-phase reflux liquid conveying device comprises: A reflux liquid pipeline (19), one end of which is connected to the sleeve (10); A three-phase solid-liquid-gas separation device, wherein the three-phase solid-liquid-gas separation device is connected to the other end of the reflux liquid pipeline (19).

7. The deep coal seam high pressure jet crushing physical fluidization mining simulation device according to claim 6 is characterized in that: The three-phase solid-liquid-gas separation device comprises: a fairing (28), an exhaust pipe (29) arranged in the fairing (28), and a reflector (30) arranged on the exhaust pipe (29) and located in the fairing (28); The fairing (28) is provided with a liquid discharge port (281) and a solid discharge port (282), and a screen (31) is installed at the liquid discharge port (281).

8. The deep coal seam high pressure jet crushing physical fluidization mining simulation device according to claim 2 is characterized in that: The gas pressurizing device comprises: An upper pressure head (20), the upper pressure head 20 being arranged at the gas inlet (204) at the top of the experimental box (2); A pressure head (21), the pressure head (21) being arranged at the gas inlet (204) at the bottom of the experimental box (2); A flow guide tube (22), one end of the flow guide tube (22) being connected to the high-pressure gas cylinder (23), and the other end of the flow guide tube (22) being connected to the upper pressure head (20) and / or the lower pressure head (21).

9. The deep coal seam high pressure jet crushing physical fluidization mining simulation device according to claim 1 is characterized in that: The depth of the deep underground coal rock is 1500 to 2500 meters; and / or, the simulation device can provide a confining pressure of 60 MPa, a temperature of 120° C., and a pore pressure of 30 MPa; And / or, the wellbore of the simulation device can withstand a pressure of 80 MPa, and the wellhead can withstand a pressure of 100 MPa.

10. A method for simulating the physical fluidization of coal and coalbed methane co-mining by high-pressure jet crushing in deep coal seams using the simulation device according to any one of claims 1 to 9, characterized in that: The following steps are involved: The coal and rock specimens are placed in an experimental box of a triaxial pressure test device, and axial pressure, axial reaction force and confining pressure are applied to the coal and rock specimens by the triaxial pressure test device to simulate the triaxial pressure of deep underground coal and rock. Pore pressure is applied to the coal and rock specimens by a gas booster device to simulate the pore pressure of deep underground coal and rock. The coal and rock specimens are cut by a hydraulic cutting test device to simulate hydraulic cutting. The fluidized liquid mixture obtained by cutting flows into a three-phase reflux liquid conveying device through a casing of the triaxial pressure test device, and the fluidized liquid mixture is separated by the three-phase reflux liquid conveying device to simulate the separation of solid-liquid-gas three-phase mixed reflux liquid.

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