Rock pulse fracturing and high-voltage pulse discharge synergistic fracturing simulation device and method

Abstract

The invention discloses a rock pulse fracturing and high-voltage pulse discharge collaborative fracturing simulation device and method.The device comprises a triaxial loading mechanism, a pulse fracturing mechanism, a high-voltage pulse discharge mechanism, a collaborative control part and a monitoring mechanism, and the triaxial loading mechanism is used for loading triaxial pressure to a rock sample; a simulation hole is formed in the upper end surface of the rock sample, and a plug is plugged at the hole opening of the simulation hole; the pulse fracturing mechanism comprises a fracturing fluid storage tank and a pulse pumping assembly; the high-voltage pulse discharge mechanism comprises a Marx generator and a discharge electrode; the monitoring mechanism comprises a plurality of acoustic emission sensors and an acoustic emission data processor. The influence of the synergistic effect of pulse fracturing and high-voltage pulse discharge on the rock fracturing process can be systematically studied, the synergistic effect mechanism of the two is disclosed by accurately controlling the fracturing fluid release rhythm and the high-voltage pulse discharge rhythm, a parameter optimization basis is provided for field fracturing operation, the fracturing effect is improved, and the rock fracturing efficiency is improved. The mining cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of rock fracturing simulation, and in particular to a device and method for simulating rock fracturing by synergistic pulse fracturing and high-voltage pulse discharge. Background Art

[0002] In the extraction of underground resources such as oil, natural gas, and geothermal energy, rock fracturing technology is one of the core methods for increasing reservoir permeability and resource productivity. Traditional fracturing methods, such as conventional hydraulic fracturing, have numerous limitations. The fractures they create are relatively uniform, mostly linear, resulting in insufficient connectivity in the fracture network, making it difficult to fully access the resources in the reservoir, thus limiting extraction efficiency. Furthermore, the high fracture pressures required for traditional fracturing not only increase energy consumption and equipment load, but also raise extraction costs.

[0003] In recent years, pulse fracturing and high-pressure pulse discharge technology, as emerging fracturing methods, have shown great potential. Pulse fracturing can generate complex stress waves by periodically changing the injection pressure and flow rate of the fracturing fluid, prompting the formation of a more complex fracture network in the rock. High-pressure pulse discharge technology uses the high energy released instantly to generate powerful shock waves and thermal effects within the rock, which also helps to form complex fractures and reduce the fracture pressure. However, the current research on the synergistic effect of these two technologies on the rock fracturing process is still in its infancy and lacks systematic and in-depth exploration. In order to better apply these two technologies to actual mining operations, it is urgent to design a scientific, comprehensive and precise experimental plan to reveal their synergistic mechanism and key influencing factors. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above technical deficiencies and propose a rock pulse fracturing and high-voltage pulse discharge collaborative fracturing simulation device and method to solve the technical problems of ×× in the prior art.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] The present invention provides a rock pulse fracturing and high-voltage pulse discharge collaborative fracturing simulation device, comprising:

[0007] A triaxial loading mechanism is used to apply triaxial pressure to the rock sample, wherein a simulation hole is opened on the upper end surface of the rock sample, and a plug is provided at the opening of the simulation hole;

[0008] A pulse fracturing mechanism, comprising a fracturing fluid storage tank and a pulse pumping assembly, wherein the inlet of the pulse pumping assembly is connected to the outlet of the fracturing fluid storage tank, and the outlet of the pulse pumping assembly is connected to the simulation hole;

[0009] A high-voltage pulse discharge mechanism comprises a Marx generator and a discharge electrode, wherein the output end of the Marx generator is electrically connected to the discharge electrode, and the discharge end of the discharge electrode is arranged in the simulation hole;

[0010] A collaborative control component, the collaborative control component is in communication with the pulse pumping assembly and the Marx generator, and is used for synchronously or asynchronously triggering fracturing fluid pulses and discharge pulses;

[0011] The monitoring mechanism includes a plurality of acoustic emission sensors and an acoustic emission data processor. The acoustic emission sensors are arranged on the periphery of the rock sample. The acoustic emission data processor is electrically connected to each of the acoustic emission sensors and is used to detect the crack expansion process in the rock sample.

[0012] In some embodiments, the three-axis loading mechanism includes a test box, an airbag cover, an upper pressure piece and a first air pump. The test box is used to place rock samples, the airbag cover is used to be mounted on the outer wall of the rock sample in the test box, the upper pressure piece is used to apply pressure on the top surface of the rock sample in the test box, and the outlet of the first air pump is connected to the airbag cover.

[0013] In some embodiments, the upper pressure piece includes a first pressure block, a connecting column, a second pressure block, a cylinder and a second air pump, the first pressure block is used to press the top surface of the rock sample in the test box, the lower end of the connecting column is fixedly connected to the first pressure block, the upper end of the connecting column is fixedly connected to the second pressure block, the fixed end of the cylinder is fixed to the inner top surface of the test box, the output end of the cylinder is fixedly connected to the second pressure block, and the outlet of the second air pump is connected to the air inlet of the cylinder.

[0014] In some embodiments, a plurality of guide holes are formed on the second pressing block, and the upper pressing member further comprises a plurality of guide posts, each of which is fixed to the inner top surface of the test box, and the guide posts are slidably connected to the guide holes.

[0015] In some embodiments, the plug is provided with a first jack; the pulse pump injection assembly includes a delivery pump, a disturbance cylinder, a pulse air pump and an injection pipe; the inlet of the delivery pump is connected to the outlet of the fracturing fluid storage tank; the disturbance cylinder includes a cylinder body, a first piston, a second piston, a connecting rod, a first one-way valve and a second one-way valve; a first accommodating chamber and a second accommodating chamber are provided in the cylinder body, and the two are connected via a connecting hole; the first piston is sealingly and slidably arranged in the first accommodating chamber; the second piston is sealingly and slidably arranged in the second accommodating chamber; the two ends of the connecting rod are respectively connected to the first accommodating chamber and the second accommodating chamber. The first piston and the second piston are fixedly connected, the connecting rod is slidably arranged in the connecting hole, the cylinder body is provided with an air inlet hole connected to the first accommodating chamber, the cylinder body is provided with a liquid inlet hole and a liquid discharge hole connected to the second accommodating chamber, the air inlet hole is connected to the outlet of the pulse air pump, the liquid inlet hole is connected to the outlet of the delivery pump, the liquid discharge hole is connected to one end of the injection pipe, the injection pipe passes through the first jack and enters the simulation hole, the first one-way valve is arranged in the liquid inlet hole, and the second one-way valve is arranged in the liquid discharge hole.

[0016] In some embodiments, the air inlet hole is connected to the outlet of the pulse air pump via an air inlet pipe.

[0017] In some embodiments, the liquid inlet hole is connected to the outlet of the delivery pump via a liquid inlet pipe.

[0018] In some embodiments, the drainage hole is connected to one end of the injection tube via a drainage tube.

[0019] In some embodiments, a second plug hole is provided on the plug, and the discharge end of the discharge electrode passes through the second plug hole and enters the simulation hole.

[0020] The present invention also provides a rock pulse fracturing and high-voltage pulse discharge collaborative fracturing simulation method, which is applicable to the rock pulse fracturing and high-voltage pulse discharge collaborative fracturing simulation device and includes the following steps:

[0021] Prepare a number of rock samples, open a simulated hole on each rock sample, and plug the opening of the simulated hole with a plug;

[0022] A rock sample was selected for a rock pulse fracturing experiment. During the experiment, the crack propagation process in the rock sample was monitored by a monitoring device to obtain the relationship between the crack propagation rate, maximum crack length, and the number of crack branches over time during the experiment.

[0023] Another rock sample was selected for a high-voltage pulse discharge experiment. During the experiment, the crack propagation process in the rock sample was monitored by a monitoring device, and the relationship between the crack propagation rate, maximum crack length, and the number of crack branches over time was obtained during the experiment.

[0024] Another rock sample was selected and subjected to a rock pulse fracturing experiment and a high-voltage pulse discharge experiment simultaneously. During the experiment, fracturing fluid was released and high-voltage pulse discharge was performed periodically, and the fracturing fluid release period was an integer multiple of the high-voltage pulse discharge period. The fracturing fluid release node coincided with the high-voltage pulse discharge node. During the experiment, the crack propagation process in the rock sample was monitored by a monitoring device, and the relationship between the crack propagation rate, maximum crack length, and the number of crack branches over time during the experiment was obtained.

[0025] Another rock sample was selected and subjected to a rock pulse fracturing experiment and a high-voltage pulse discharge experiment simultaneously. During the experiment, fracturing fluid was released and high-voltage pulse discharge was performed periodically, and the fracturing fluid release period was an integer multiple of the high-voltage pulse discharge period. The fracturing fluid release node and the high-voltage pulse discharge node were staggered by a preset time. During the experiment, the crack propagation process in the rock sample was monitored by a monitoring device, and the relationship between the crack propagation rate, maximum crack length, and the number of crack branches over time during the experiment was obtained.

[0026] The relationship between the crack propagation velocity, maximum crack length and number of crack branches obtained from each experiment and time was compared to determine the relationship between the synergistic fracturing effect of rock pulse fracturing and high-voltage pulse discharge and the degree of coincidence between the pulse fracturing nodes and the high-voltage pulse discharge nodes.

[0027] Compared with the existing technology, the beneficial effects of the rock pulse fracturing and high-voltage pulse discharge synergistic fracturing simulation device and method provided by the present invention are: the experimental scheme of the present invention can systematically study the influence of the synergistic effect of pulse fracturing and high-voltage pulse discharge on the rock fracturing process, and by precisely controlling the rhythm of fracturing fluid release and the rhythm of high-voltage pulse discharge, reveal the synergistic mechanism between the two, provide a parameter optimization basis for on-site fracturing operations, help improve fracturing effects, and reduce mining costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic structural diagram of a rock pulse fracturing and high-voltage pulse discharge collaborative fracturing simulation device provided by one embodiment of the present invention;

[0029] Figure 2 yes Figure 1 Structural diagram of the three-axis loading mechanism in FIG;

[0030] Figure 3 yes Figure 1 Schematic diagram of the structure of the disturbance cylinder;

[0031] Explanation of the accompanying symbols: 1-three-axis loading mechanism, 11-test box, 12-air bag cover, 13-upper pressure piece, 131-first pressure block, 132-connecting column, 133-second pressure block, 134-cylinder, 135-second air pump, 136-guide column, 137-second connecting pipe, 14-first air pump, 15-first connecting pipe, 2-pulse fracturing mechanism, 21-fracturing fluid storage tank, 22-pulse pump injection assembly, 221-delivery pump, 222-disturbance cylinder, 2221-cylinder body, 22211-air inlet, 22212-liquid inlet , 22213-drainage hole, 2222-first piston, 2223-second piston, 2224-connecting rod, 2225-first one-way valve, 2226-second one-way valve, 223-pulse air pump, 224-injection pipe, 225-air inlet pipe, 226-liquid inlet pipe, 227-drainage pipe, 3-pressure pulse discharge mechanism, 31-Marx generator, 32-discharge electrode, 33-cable, 4-monitoring mechanism, 41-acoustic emission sensor, 42-acoustic emission data processor, 5-rock sample, 51-simulation hole, 52-plug. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0033] The technical solutions in the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. The described embodiments are only possible technical implementations of the present invention, but are not limited thereto. Those skilled in the art can fully combine the embodiments of the present invention, and other embodiments obtained without creative work are also within the scope of protection of the present invention.

[0034] This application mainly uses pulse fracturing and high-voltage pulse discharge to simulate rock fracturing in a coordinated manner, achieving the goal of systematically studying the synergistic mechanism and influencing factors of the two and improving the effect of rock fracturing. The following is a further detailed description of this application.

[0035] Example 1

[0036] Please refer to Figure 1-Figure 3The rock pulse fracturing and high-pressure pulse discharge collaborative fracturing simulation device provided in the embodiment of the present application includes a triaxial loading mechanism 1, a pulse fracturing mechanism 2, a high-pressure pulse discharge mechanism 3, a collaborative control component and a monitoring mechanism 4, wherein the triaxial loading mechanism 1 applies triaxial pressure to the rock sample 5 to simulate the real formation environment, the pulse fracturing mechanism 2 injects fracturing fluid into the simulated hole 51 of the rock sample 5, the high-pressure pulse discharge mechanism 3 discharges in the simulated hole 51 to generate shock waves, the collaborative control component controls the triggering of the fracturing fluid pulse and the discharge pulse, and the monitoring mechanism 4 detects the crack expansion process in the rock sample 5, thereby achieving the effect of accurately simulating the rock pulse fracturing and high-pressure pulse discharge collaborative fracturing process, and studying the synergistic mechanism and key influencing factors of the two.

[0037] For details, please refer to Figure 2 A simulation hole 51 is opened on the upper end surface of the rock sample 5 , and a plug 52 is plugged at the opening of the simulation hole 51 .

[0038] For details, please refer to Figure 1-Figure 3 The triaxial loading mechanism 1 comprises a test chamber 11, an airbag housing 12, an upper pressure member 13, and a first air pump 14. The test chamber 11 is typically made of high-strength metal and is typically rectangular or cube-shaped. Its interior is used to house the rock sample 5. A closable door is provided on the side of the test chamber 11 to facilitate insertion of the rock sample 5. A transparent observation window is also provided on the side of the test chamber 11 for real-time monitoring of the experimental progress. The airbag housing 12 is made of an elastic rubber material, offering excellent flexibility and sealing properties. It fits tightly around the outer wall of the rock sample 5 within the test chamber 11. The upper pressure member 13 is used to apply pressure to the top surface of the rock sample 5. The outlet of the first air pump 14 is connected to the airbag housing 12 via a first connecting pipe 15. The first air pump 14 can also be replaced by an air compressor. When the first air pump 14 is in operation, it delivers gas through the first connecting pipe 15 into the airbag housing 12, causing it to expand and apply pressure to the sides of the rock sample 5. The first connecting pipe 15 is usually made of a pressure-resistant rubber tube or a metal tube to ensure the stability of gas transportation.

[0039] The upper pressure piece 13 includes a first pressure block 131, a connecting column 132, a second pressure block 133, a cylinder 134 and a second air pump 135. The first pressure block 131 is made of high-strength metal and is generally annular in shape. It is directly pressed against the top surface of the rock sample 5 in the test box 11. The two ends of the connecting column 132 are fixedly connected to the first pressure block 131 and the second pressure block 133 respectively, playing the role of transmitting pressure. The connecting column 132 is usually a cylindrical metal rod. The second pressure block 133 is also made of metal and its shape matches that of the first pressure block 131. The fixed end of the cylinder 134 is fixed to the inner top surface of the test box 11, and the output end is fixedly connected to the second pressure block 133. The outlet of the second air pump 135 is connected to the air inlet of the cylinder 134 through the second connecting pipe 137. The second air pump 135 can also be replaced by an electric air pump. When the second air pump 135 is working, the gas is transported into the cylinder 134 through the second connecting pipe 137. The output end of the cylinder 134 extends, driving the second pressure block 133, the connecting column 132 and the first pressure block 131 to move downward, applying pressure to the top surface of the rock sample 5. The material and requirements of the second connecting pipe 137 are similar to those of the first connecting pipe 15. In addition, a number of guide holes are provided on the second pressure block 133, and the upper pressure piece 13 also includes a number of guide columns 136. Each guide column 136 is fixed to the inner top surface of the test box 11, and the guide column 136 is slidably connected to the guide hole. The guide column 136 is generally a smooth metal rod, and the inner wall of the guide hole is also finely processed, which can ensure the stability of the upper pressure piece 13 during the up and down movement and make the applied pressure more uniform.

[0040] Please refer to Figure 1-Figure 3The pulse fracturing mechanism 2 includes a fracturing fluid storage tank 21 and a pulse pump assembly 22. The fracturing fluid storage tank 21 is usually made of corrosion-resistant metal or plastic and is used to store fracturing fluid. The inlet of the pulse pump assembly 22 is connected to the outlet of the fracturing fluid storage tank 21, and the outlet is connected to the simulation hole 51. A first plug hole is provided on the plug 52 to facilitate the injection pipe 224 of the pulse pump assembly 22 to pass through and enter the simulation hole 51. The pulse pump assembly 22 includes a delivery pump 221, a disturbance cylinder 222, a pulse air pump 223 and an injection pipe 224. The inlet of the delivery pump 221 is connected to the outlet of the fracturing fluid storage tank 21 and is used to extract the fracturing fluid from the tank. The delivery pump 221 can be a centrifugal pump or a plunger pump. The disturbance cylinder 222 includes a cylinder body 2221, a first piston 2222, a second piston 2223, a connecting rod 2224, a first one-way valve 2225 and a second one-way valve 2226. Cylinder body 2221 is generally made of metal and has a first accommodating chamber and a second accommodating chamber connected via a connecting hole. The first piston 2222 and the second piston 2223 are made of wear-resistant rubber or plastic and are sealed and slidably disposed within the first and second accommodating chambers, respectively. The connecting rod 2224 is fixedly connected to the first and second pistons 2222 and 2223 at both ends and slides within the connecting hole. Cylinder body 2221 is provided with an air inlet 22211 connected to the first accommodating chamber, and a liquid inlet 22212 and a liquid outlet 22213 connected to the second accommodating chamber. The air inlet 22211 is connected to the outlet of the pulse air pump 223 via an air inlet pipe 225. The liquid inlet 22212 is connected to the outlet of the delivery pump 221 via a liquid inlet pipe 226. The liquid discharge 22213 is connected to one end of the injection pipe 224 via a liquid discharge pipe 227. All three pipes must be pressure-resistant. A first one-way valve 2225 is located within the liquid inlet 22212, allowing only fracturing fluid to flow from the liquid inlet pipe 226 into the second accommodating chamber. A second one-way valve 2226 is located within the liquid discharge 22213, allowing only fracturing fluid to flow from the second accommodating chamber into the liquid discharge pipe 227.

[0041] In this embodiment, the pulse air pump 223 can periodically pump and exhaust air. When working, the delivery pump 221 starts working. Since the inlet of the delivery pump 221 is connected to the outlet of the fracturing fluid storage tank 21, it can extract the fracturing fluid from the storage tank. The pulse air pump 223 starts to work periodically. When the pulse air pump 223 is in the pumping state, the air pressure in the first accommodating chamber of the cylinder body 2221 of the disturbance cylinder 222 decreases. Since the first piston 2222 and the second piston 2223 are connected by the connecting rod 2224, and the sealing sliding is arranged in the first accommodating chamber and the second accommodating chamber, the first piston 2222 will move toward the air inlet 22211 under the action of the air pressure difference, thereby driving the second piston 2223 to move synchronously in the second accommodating chamber. At this time, the volume of the second accommodating chamber increases and the internal pressure decreases. Because the first one-way valve 2225 is located within the inlet port 22212, it only allows fracturing fluid to flow from the inlet pipe 226 into the second chamber. Under the influence of the pressure differential, the fracturing fluid flows from the outlet of the delivery pump 221 through the inlet pipe 226 into the second chamber. When the pulse air pump 223 is in the exhaust state, high-pressure gas enters the first chamber through the inlet port 22211 via the inlet pipe 225, increasing the pressure within the first chamber. Under the influence of the gas pressure, the first piston 2222 moves toward the connecting hole, driving the second piston 2223 to move synchronously within the second chamber via the connecting rod 2224. This reduces the volume of the second chamber and increases the internal pressure. Because the second one-way valve 2226 is located within the discharge port 22213, it only allows the fracturing fluid to flow from the second chamber into the discharge pipe 227. Under the influence of the pressure, the fracturing fluid flows from the second chamber into the injection pipe 224 through the discharge pipe 227. The injection pipe 224 injects the fracturing fluid into the simulation hole 51. Since the pulse air pump 223 periodically pumps and exhausts air, the fracturing fluid is injected into the simulation hole 51 in the form of pulses, thereby achieving the effect of pulse fracturing.

[0042] Please refer to Figure 1 and Figure 2 The high-voltage pulse discharge mechanism 3 includes a Marx generator 31 and a discharge electrode 32. The output end of the Marx generator 31 is electrically connected to the discharge electrode 32 via a cable 33. A second jack is provided on the plug 52, through which the discharge end of the discharge electrode 32 passes and enters the simulation hole 51. The Marx generator 31 can generate high-voltage pulses. The discharge electrode 32 is generally made of a metal with good electrical conductivity. When the Marx generator 31 is operating, a high-energy pulse discharge is generated at the discharge end of the discharge electrode 32, generating a powerful shock wave and thermal effect within the rock sample 5, promoting the formation of cracks.

[0043] The collaborative control unit is in communication with both the pulse pump assembly 22 and the Marx generator 31. It can be an integrated electronic controller with programming and control functions. Through the collaborative control unit, the fracturing fluid pulse and the discharge pulse can be triggered synchronously or asynchronously to achieve different experimental conditions.

[0044] Please refer to Figure 1 and Figure 2 The monitoring mechanism 4 includes several acoustic emission sensors 41 and an acoustic emission data processor 42. The acoustic emission sensors 41, typically piezoelectric ceramic sensors, are positioned around the periphery of the rock sample 5 and are capable of sensitively detecting the acoustic emission signals generated by the rock sample 5 during the fracturing process. The acoustic emission data processor 42 is electrically connected to each acoustic emission sensor 41 and processes and analyzes the signals collected by the acoustic emission sensors 41 to detect the crack propagation process within the rock sample 5 and record the temporal relationship between the crack propagation rate, maximum crack length, and the number of crack branches.

[0045] The implementation principle of this embodiment is as follows: a triaxial loading mechanism 1 simulates the actual stress environment of a rock sample 5 underground. A pulse fracturing mechanism 2 and a high-voltage pulse discharge mechanism 3 respectively apply pulse fracturing and high-voltage pulse discharge to the rock sample 5. A coordinated control element controls the triggering sequence and time interval of the two, and a monitoring mechanism 4 monitors the crack propagation process within the rock sample 5 in real time. This method allows for systematic study of the synergistic mechanism and key influencing factors of rock pulse fracturing and high-voltage pulse discharge. Compared to traditional single fracturing methods, this method provides a more comprehensive understanding of the fracturing process, providing a scientific basis for actual underground resource extraction, improving extraction efficiency, and reducing extraction costs.

[0046] Example 2

[0047] This embodiment differs from the previous embodiment in that the airbag sleeve 12 of the triaxial loading mechanism 1 can be replaced by a hydraulic bladder. The hydraulic bladder can also be placed on the outer wall of the rock sample 5. Liquid is injected into the hydraulic bladder through a hydraulic pump, causing the hydraulic bladder to expand and apply pressure to the rock sample 5.

[0048] The principle behind this embodiment is that a hydraulic bladder, instead of the airbag sleeve 12, allows for more precise control of the pressure applied to the side of the rock sample 5. Liquids are more incompressible than gases, resulting in more stable pressure transmission. This improves the accuracy of simulation experiments, more accurately simulating the actual stress conditions in underground rock, and thus allows for deeper research into the synergistic fracturing effects of rock pulse fracturing and high-voltage pulse discharge.

[0049] Example 3

[0050] The rock pulse fracturing and high-voltage pulse discharge synergistic fracturing simulation method provided in the embodiments of the present application includes the following steps:

[0051] S1. Prepare several rock samples. These can be obtained from actual mining sites or prepared through artificial synthesis. The lithology, appearance, and dimensions of each rock sample 5 must be consistent. Simulated holes 51 are drilled in each rock sample using drilling equipment. The size and depth of the holes are determined based on experimental requirements. A plug 52 is then inserted into the opening of the simulated hole 51. The plug 52 has an interference fit with the opening of the simulated hole 51. The plug 52 and the rock sample 5 can also be connected using expansion screws to enhance the connection strength of the plug 52 and prevent it from being dislodged by the high-pressure fluid in the simulated hole 51. The plug 52 must maintain a good seal to prevent leakage of the fracturing fluid.

[0052] S2, select a rock sample 5 and conduct a rock pulse fracturing experiment. First, place the rock sample 5 in the test box 11 of the triaxial loading mechanism 1, and apply triaxial pressure to the rock sample 5 through the triaxial loading mechanism 1 to simulate the real formation environment. Start the pulse fracturing mechanism 2, and pump the fracturing fluid from the fracturing fluid storage tank 21 through the delivery pump 221. After the disturbance of the pulse pump injection component 22, the pulsed fracturing fluid is injected into the simulated hole 51. During the experiment, the acoustic emission sensor 41 of the monitoring mechanism 4 monitors the crack expansion process in the rock sample 5 in real time. The acoustic emission sensor 41 transmits the collected signal to the acoustic emission data processor 42. The acoustic emission data processor 42 processes and analyzes the signal to obtain the relationship between the crack expansion speed, the maximum crack length and the number of crack branches over time during the experiment.

[0053] In step S3, another rock sample 5 is selected for a high-voltage pulse discharge experiment. Similarly, the rock sample 5 is placed in the test chamber 11 and subjected to triaxial pressure. The high-voltage pulse discharge mechanism 3 is activated, and the Marx generator 31 generates a high-voltage pulse, which is discharged into the simulated hole 51 via the discharge electrode 32. During the experiment, the monitoring mechanism 4 monitors the crack propagation process in the rock sample 5, recording the changes in the crack propagation rate, maximum crack length, and number of crack branches over time.

[0054] S4: Another rock sample 5 is selected and subjected to both a rock pulse fracturing experiment and a high-voltage pulse discharge experiment. During the experiment, the fracturing fluid is released and the high-voltage pulse discharge is performed periodically through a coordinated control component, with the fracturing fluid release period being an integer multiple of the high-voltage pulse discharge period, while ensuring that the fracturing fluid release node coincides with the high-voltage pulse discharge node. During this process, the crack propagation process in the rock sample 5 is continuously monitored by the monitoring device 4, and the corresponding relationship between the crack propagation rate, maximum crack length, and the number of crack branches over time is obtained.

[0055] S5: Select another rock sample 5 and perform the same rock pulse fracturing and high-voltage pulse discharge experiments simultaneously. During the experiment, the fracturing fluid release and high-voltage pulse discharge are still performed periodically, with the fracturing fluid release period being an integer multiple of the high-voltage pulse discharge period. However, the fracturing fluid release and high-voltage pulse discharge points are staggered by a preset time. Simultaneously, the crack growth process in rock sample 5 is monitored and recorded using monitoring device 4.

[0056] S6: Compare and analyze the relationship between the crack growth rate, maximum crack length, and number of crack branches obtained from each experiment over time. Professional data analysis software can be used to plot crack growth curves under different experimental conditions, visually observing differences in crack growth rate and extent. By comparing these curves, the synergistic fracturing effect between rock pulse fracturing and high-voltage pulse discharge can be determined, as well as the degree of agreement between the pulse fracturing nodes and the high-voltage pulse discharge nodes.

[0057] The implementation principle of this embodiment is to study the rock fracture expansion under pulse fracturing, high-voltage pulse discharge, and the synergistic effects of these two methods through a series of experiments under different conditions. By comparing the relationship between fracture propagation rate, maximum fracture length, and number of fracture branches over time under different experimental conditions, we can clearly understand the impact of the consistency between pulse fracturing nodes and high-voltage pulse discharge nodes on the synergistic fracturing effect. This provides a scientific basis for optimizing rock fracturing technology, helps improve the extraction efficiency of underground resources, and reduces extraction costs. Compared with traditional single-method research methods, it is more systematic and comprehensive.

[0058] In a certain actual experimental process, the experimental conditions and measurement results of each group are shown in the following table:

[0059] Table 1: Summary of experimental conditions and measurement results for each group

[0060]

[0061] The comparative analysis of the above experimental results is as follows:

[0062] (1) Crack propagation efficiency: The synergistic-synchronous triggering group (S4) performed best, with crack propagation speed and length significantly higher than those of the other groups, indicating that the synchronous superposition effect of fracturing fluid and discharge shock waves can effectively enhance rock fragmentation. The high-voltage discharge group (S3), although with a high instantaneous speed, had a limited crack propagation range (localized) and relied on the penetration and expansion effect of the fracturing fluid.

[0063] (2) Crack complexity: The synchronous triggering group has the largest number of crack branches (8 to 12), indicating that the synergistic effect can induce multi-directional crack expansion, while the crack branches in the asynchronous triggering group are reduced by about 40%, which may be related to the timing of energy superposition.

[0064] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A rock pulse fracturing and high-voltage pulse discharge collaborative fracturing simulation device, characterized in that: include: A triaxial loading mechanism is used to apply triaxial pressure to the rock sample, wherein a simulation hole is opened on the upper end surface of the rock sample, and a plug is provided at the opening of the simulation hole; A pulse fracturing mechanism, comprising a fracturing fluid storage tank and a pulse pumping assembly, wherein the inlet of the pulse pumping assembly is connected to the outlet of the fracturing fluid storage tank, and the outlet of the pulse pumping assembly is connected to the simulation hole; A high-voltage pulse discharge mechanism includes a Marx generator and a discharge electrode, wherein the output end of the Marx generator is electrically connected to the discharge electrode, and the discharge end of the discharge electrode is arranged in the simulation hole; A collaborative control component, in communication with the pulse pumping assembly and the Marx generator, for synchronously or asynchronously triggering fracturing fluid pulses and discharge pulses; The monitoring mechanism includes a plurality of acoustic emission sensors and an acoustic emission data processor. The acoustic emission sensors are arranged on the periphery of the rock sample. The acoustic emission data processor is electrically connected to each of the acoustic emission sensors and is used to detect the crack expansion process in the rock sample.

2. The rock pulse fracturing and high-voltage pulse discharge synergistic fracturing simulation device according to claim 1 is characterized in that: The triaxial loading mechanism includes a test box, an airbag cover, an upper pressure piece and a first air pump. The test box is used to place rock samples. The airbag cover is used to be mounted on the outer wall of the rock sample in the test box. The upper pressure piece is used to apply pressure to the top surface of the rock sample in the test box. The outlet of the first air pump is connected to the airbag cover.

3. The rock pulse fracturing and high-voltage pulse discharge synergistic fracturing simulation device according to claim 2 is characterized in that: The upper pressure piece includes a first pressure block, a connecting column, a second pressure block, a cylinder and a second air pump. The first pressure block is used to press the top surface of the rock sample in the test box. The lower end of the connecting column is fixedly connected to the first pressure block, and the upper end of the connecting column is fixedly connected to the second pressure block. The fixed end of the cylinder is fixed to the inner top surface of the test box, the output end of the cylinder is fixedly connected to the second pressure block, and the outlet of the second air pump is connected to the air inlet of the cylinder.

4. The rock pulse fracturing and high-voltage pulse discharge synergistic fracturing simulation device according to claim 3 is characterized in that: The second pressing block is provided with a plurality of guide holes, and the upper pressing piece further comprises a plurality of guide posts, each of which is fixed to the inner top surface of the test box, and the guide posts are slidably connected to the guide holes.

5. The rock pulse fracturing and high-voltage pulse discharge synergistic fracturing simulation device according to claim 1 is characterized in that: The plug is provided with a first plug hole; The pulse pump injection assembly includes a delivery pump, a disturbance cylinder, a pulse air pump, and an injection pipe. The inlet of the delivery pump is connected to the outlet of the fracturing fluid storage tank. The disturbance cylinder includes a cylinder body, a first piston, a second piston, a connecting rod, a first one-way valve, and a second one-way valve. The cylinder body has a first accommodating chamber and a second accommodating chamber, which are connected via a connecting hole. The first piston is sealingly and slidably disposed in the first accommodating chamber, and the second piston is sealingly and slidably disposed in the second accommodating chamber. The two ends of the connecting rod are fixedly connected to the first piston and the second piston respectively. The connecting rod is slidably disposed in the connecting hole. The cylinder body is provided with an air inlet hole communicating with the first accommodating chamber. The cylinder body is provided with a liquid inlet hole and a liquid discharge hole communicating with the second accommodating chamber. The air inlet hole is connected to the outlet of the pulse air pump, the liquid inlet hole is connected to the outlet of the delivery pump, and the liquid discharge hole is connected to one end of the injection pipe. The injection pipe passes through the first insertion hole and enters the simulation hole. The first one-way valve is disposed in the liquid inlet hole, and the second one-way valve is disposed in the liquid discharge hole.

6. The rock pulse fracturing and high-voltage pulse discharge synergistic fracturing simulation device according to claim 5 is characterized in that: The air inlet hole is communicated with the outlet of the pulse air pump via an air inlet pipe.

7. The rock pulse fracturing and high-voltage pulse discharge synergistic fracturing simulation device according to claim 5 is characterized in that: The liquid inlet hole is communicated with the outlet of the delivery pump via a liquid inlet pipe.

8. The rock pulse fracturing and high-voltage pulse discharge synergistic fracturing simulation device according to claim 5 is characterized in that: The drainage hole is connected to one end of the injection pipe via a drainage pipe.

9. The rock pulse fracturing and high-voltage pulse discharge synergistic fracturing simulation device according to claim 1 is characterized in that: The plug is provided with a second insertion hole, and the discharge end of the discharge electrode passes through the second insertion hole and enters the simulation hole.

10. A rock pulse fracturing and high-voltage pulse discharge synergistic fracturing simulation method, characterized in that: The device is applicable to the rock pulse fracturing and high-voltage pulse discharge synergistic fracturing simulation device according to any one of claims 1 to 9, and comprises the following steps: Prepare a number of rock samples, open a simulated hole on each rock sample, and plug the opening of the simulated hole with a plug; A rock sample was selected for a rock pulse fracturing experiment. During the experiment, the crack propagation process in the rock sample was monitored by a monitoring device to obtain the relationship between the crack propagation rate, maximum crack length, and the number of crack branches over time during the experiment. Another rock sample was selected for a high-voltage pulse discharge experiment. During the experiment, the crack propagation process in the rock sample was monitored by a monitoring device, and the relationship between the crack propagation rate, maximum crack length, and the number of crack branches over time was obtained during the experiment. Another rock sample was selected and subjected to a rock pulse fracturing experiment and a high-voltage pulse discharge experiment simultaneously. During the experiment, fracturing fluid was released and high-voltage pulse discharge was performed periodically, and the fracturing fluid release period was an integer multiple of the high-voltage pulse discharge period. The fracturing fluid release node coincided with the high-voltage pulse discharge node. During the experiment, the crack propagation process in the rock sample was monitored by a monitoring device, and the relationship between the crack propagation rate, maximum crack length, and the number of crack branches over time during the experiment was obtained. Another rock sample was selected and subjected to a rock pulse fracturing experiment and a high-voltage pulse discharge experiment simultaneously. During the experiment, fracturing fluid was released and high-voltage pulse discharge was performed periodically, and the fracturing fluid release period was an integer multiple of the high-voltage pulse discharge period. The fracturing fluid release node and the high-voltage pulse discharge node were staggered by a preset time. During the experiment, the crack propagation process in the rock sample was monitored by a monitoring device, and the relationship between the crack propagation rate, maximum crack length, and the number of crack branches over time during the experiment was obtained. The relationship between the crack propagation velocity, maximum crack length and number of crack branches obtained from each experiment and time was compared to determine the relationship between the synergistic fracturing effect of rock pulse fracturing and high-voltage pulse discharge and the degree of coincidence between the pulse fracturing nodes and the high-voltage pulse discharge nodes.

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