A triaxial pulse-type shock wave fracturing rock experimental system

Abstract

The application provides a triaxial pulse shock wave fracturing rock experiment system, which comprises a rock sample, a base, a hoop loading mechanism, a vertical loading mechanism, a rock displacement mechanism, a shock wave generator, a shaft, a pressure sensor and an electric heating assembly. The rock sample is installed on the rock displacement mechanism. The hoop loading mechanism is installed on the top end of the base in a lifting manner. The vertical loading mechanism and the rock displacement mechanism are both slidingly installed on the top end of the base. The hoop loading mechanism surrounds the side of the rock sample. The vertical loading mechanism is located above the rock sample. The top of the shock wave generator is installed on the vertical loading mechanism. The bottom of the shock wave generator and the shaft are both installed in the rock sample. The shaft is located below the shock wave generator. The output ends of the hoop loading mechanism and the vertical loading mechanism are both installed with the pressure sensor and the electric heating assembly.

Description

Technical Field

[0001] This invention relates to the field of rock mechanics experimental technology, and in particular to a triaxial pulsed shock wave rock fracturing experimental system. Background Technology

[0002] Pulsed controllable shock wave rock fracturing technology, based on high-power electrical pulse technology and discharge plasma, converts electrical and chemical energy into mechanical energy. By repeatedly operating a pulse power-driven source, shock waves are repeatedly generated in a controlled area. As an emerging reservoir stimulation technology, it has achieved good application results in oil and gas well unblocking, fracturing, and permeability enhancement. Compared with previous fracturing technologies, pulsed controllable shock wave fracturing technology has a series of advantages, including lower energy consumption, higher efficiency, lower cost, safety and environmental friendliness, higher operational efficiency, and easier control.

[0003] Actual reservoirs are located in deep strata, subjected to high in-situ stress and specific temperature environments. Therefore, pulsed controlled shock wave tests that consider both in-situ stress and temperature are essential to accurately reflect the fracture characteristics of actual reservoirs. Furthermore, large-volume rocks are necessary for accurately simulating reservoir fracture characteristics. These large rocks are at least one meter in length, width, and height, making them heavy and difficult to handle. Currently, there is no suitable experimental scheme for controlled shock wave fracturing of large-volume rocks, thus hindering the successful implementation of controlled shock wave reservoir modification. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a triaxial pulse shock wave fracturing rock experimental system to address the shortcomings of the prior art.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A triaxial pulsed shock wave fracturing rock experimental system includes: a rock sample, a base, a circumferential loading mechanism, a vertical loading mechanism, a rock displacement mechanism, a shock wave generator, a wellbore, a pressure sensor, and an electric heating component. The rock sample is mounted on the rock displacement mechanism. The circumferential loading mechanism is vertically mounted on the top of the base. The vertical loading mechanism and the rock displacement mechanism are both slidably mounted on the top of the base. The circumferential loading mechanism surrounds the periphery of the rock sample. The vertical loading mechanism is located above the rock sample. The top of the shock wave generator is mounted on the vertical loading mechanism. The bottom of the shock wave generator and the wellbore are both installed in the rock sample. The wellbore is located below the shock wave generator. The pressure sensor and the electric heating component are installed at the output ends of the circumferential loading mechanism and the vertical loading mechanism, respectively.

[0006] The beneficial effects of adopting the technical solution of this invention are as follows: By setting a circumferential loading mechanism, horizontal stress can be applied to the rock sample; by setting a vertical loading mechanism, vertical stress can be applied to the rock sample, thereby realizing a true triaxial stress environment. The vertical loading mechanism is movable, facilitating the placement and removal of the rock sample. The rock displacement mechanism assists the staff in transporting the rock sample and moving it to a set position for successful stress loading. It is suitable for large-volume rocks and can simulate the shock wave fracturing reservoir process under real formation environments (high temperature, high pressure) and wellbore conditions (casing, cementing, perforation). It facilitates the observation of the propagation law of rock fractures caused by pulsed controllable shock wave fracturing, enabling large-scale rock samples (2m×2m×1m) to undergo pulsed controllable shock wave fracturing rock physics simulation experiments under near-formation true triaxial stress conditions, achieving organic unity between indoor experimental conditions and field construction parameters. The structure is reasonably designed, easy to operate, and highly safe, greatly improving the efficiency of the experimental process and providing accurate experimental results.

[0007] Furthermore, the vertical loading mechanism includes: a movable frame, a vertical force application device, and a vertical force application plate. The movable frame has an overall n-shaped structure. The top of the base is provided with a sliding groove, and the bottom of the movable frame is slidably installed in the sliding groove. The top of the vertical force application device and the top of the shock wave generator are both installed on the top of the movable frame. The vertical force application plate is installed on the vertical force application device and is located above the rock sample. The pressure sensor and the electric heating assembly are installed on the vertical force application plate.

[0008] The beneficial effects of adopting the above-mentioned further technical solution are: the n-shaped movable frame can accommodate the circumferential loading mechanism, and the movable frame of the vertical loading mechanism can move, thereby facilitating the placement and removal of rock samples. An installation space is formed between the movable frame and the base. The structure of the chute and the lower end of the movable frame not only enables the movable frame to move, but also smoothly applies vertical stress to the rock sample. When applying vertical stress, the upper surface of the lower end of the movable frame abuts against the top wall of the chute.

[0009] Furthermore, the bottom of the movable frame has an L-shaped structure, the slide groove is an L-shaped slide groove, and the bottom end of the movable frame is provided with a movable wheel.

[0010] The beneficial effects of adopting the above-mentioned further technical solution are: the structural design of the chute and the lower end of the moving frame not only enables the moving frame to move, but also allows for the smooth application of vertical stress to the rock sample. When applying vertical stress, the upper surface of the lower end of the moving frame abuts against the top wall of the chute. The moving wheels at the lower end of the moving frame facilitate its movement.

[0011] Furthermore, the circumferential loading mechanism includes: an annular frame, a first horizontal force-applying device, a second horizontal force-applying device, and a horizontal force-applying plate. The annular frame is vertically and flexibly installed at the top of the base. The annular frame is located in the vertical loading mechanism. The annular frame is a cubic loading space with open ends. The first horizontal force-applying device and the second horizontal force-applying device are installed one-to-one on two adjacent first inner sidewalls of the annular frame. The output ends of the first horizontal force-applying device and the second horizontal force-applying device are each equipped with the horizontal force-applying plate. The pressure sensor and the electric heating assembly are installed on the horizontal force-applying plate. The two adjacent second inner sidewalls of the annular frame are both load-bearing bodies.

[0012] The beneficial effect of adopting the above-mentioned further technical solution is that by setting up a first horizontal force application device, a second horizontal force application device, and two bearing bodies, the horizontal stress on the rock sample on the base can be applied, avoiding the structural complexity problem of needing to set up four force application devices.

[0013] Furthermore, the horizontal force-applying plate includes: an abutment plate, a force-transmitting plate, and a heat insulation layer. The output ends of the first horizontal force-applying device and the second horizontal force-applying device are both equipped with the force-transmitting plate. The pressure sensor is installed on the force-transmitting plate, the abutment plate is installed on the pressure sensor, the electric heating component and the heat insulation layer are both installed in the abutment plate, the heat insulation layer is adjacent to the pressure sensor, and a casting template is detachably installed on the carrier.

[0014] The beneficial effects of adopting the above-mentioned further technical solution are as follows: A pressure sensor is positioned between the abutment plate and the force transmission plate, with the abutment plate closer to the true triaxial stress simulation space. The pressure sensor is used to monitor the stress magnitude in real time. Electric heating components and insulation layers are respectively installed on both sides inside the abutment plate, with the insulation layer closer to the pressure sensor. The electric heating components can heat the rock sample, thereby simulating the temperature environment of deep strata. Electric heating components can also be installed inside the load-bearing plate and the support plate to uniformly heat the rock sample and improve the heating effect.

[0015] Furthermore, the rock displacement mechanism includes: a support plate, a frame lifting device, a hanging ring, a support plate lifting device, a load-bearing plate, and a telescopic device. The top of the base is provided with a rectangular groove, which extends to the bottom of the circumferential loading mechanism. The rock sample is mounted on the support plate, which is slidably mounted in the rectangular groove. The top of the support plate is flush with the top of the base. The top of the support plate is provided with an installation groove, in which the hanging ring is mounted. The frame lifting device is mounted on the top of the base, and its output end is connected to the circumferential loading mechanism. The telescopic device is mounted on each of the two adjacent second inner sidewalls of the circumferential loading mechanism. The load-bearing plate is mounted on the output end of the telescopic device. The support plate lifting device is mounted at the middle of the top of the base, and its output end abuts against the support plate.

[0016] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The rock displacement mechanism can assist workers in transferring rock samples and moving them to a set position for smooth stress loading. The rectangular groove facilitates the movement of the support plate, and after movement, the upper surface of the support plate is flush with the upper surface of the base, thus not affecting stress loading. The hanging ring is set in the installation groove, so it will not affect the placement of the rock sample or interfere with the annular frame. The rectangular groove extends circumferentially to the bottom of the carrier, while the other side of the annular frame does not extend. In actual use, the area of ​​the support plate is larger than the bottom area of ​​the rock sample, which facilitates the fixing and hoisting of the rock sample. The excess part of the support plate can be accommodated in the rectangular groove below the annular frame, allowing the rock sample to contact the carrier and facilitating the loading of horizontal stress. The frame lifting device is used to lift the annular frame, making it easier for the support plate to be inserted into the lower part of the annular frame after movement. The telescopic device can push the rock sample to move through the load-bearing plate, thereby achieving the purpose of uniform force application.

[0017] Furthermore, the output end of the support plate lifting device is provided with a spherical cavity, and a ball bearing is provided in the spherical cavity, the ball bearing abutting against the support plate.

[0018] The beneficial effects of adopting the above-mentioned further technical solution are: the ball bearings enable the support plate to move in all directions and have high strength. The support plate lifting device can lift the rock sample and the support plate together, allowing the support plate to move on the ball bearings, thereby reducing the friction during the movement of the support plate and avoiding the problem of the rock sample being too large to handle.

[0019] Furthermore, a fixing ring is installed on the top of the shock wave generator, a stepped hole is provided on the top of the vertical loading mechanism, the fixing ring is installed in the stepped hole, and a window for the shock wave to pass through is provided at the bottom of the shock wave generator, the window being located in the rock sample.

[0020] The advantages of adopting the above-mentioned further technical solution are: it facilitates the replacement of the metal wires or energy bars of the shock wave generator by the staff. The shock wave generator can be installed by a hoisting mechanism and temporarily fixed by a fixing ring and a movable frame. The lower end of the shock wave generator is provided with a window for the shock wave to pass through, and the window is located in the true triaxial stress simulation space.

[0021] Furthermore, a hoisting mechanism is provided above the base, and the hoisting rope of the hoisting mechanism is connected to the rock displacement mechanism. The rock sample is installed on the rock displacement mechanism by a fixing rope.

[0022] The beneficial effects of adopting the above-mentioned further technical solutions are: the rock displacement mechanism and the hoisting mechanism can assist workers in transferring rock samples and moving them to a set position for smooth stress loading. The lower end of the hoisting rope of the hoisting mechanism is used to engage with the hanging ring, and both ends of the fixing rope are used to engage with the hanging ring. The hoisting mechanism is used for hoisting the rock sample in and out, and can be in the form of an overhead crane or a hoist. The fixing rope can secure the rock sample and the support plate.

[0023] Furthermore, the rock sample has a cubic structure, the wellbore has an inner diameter of 127 mm, and the wellbore has a wall thickness of 10 mm.

[0024] The beneficial effect of adopting the above-mentioned further technical solutions is to improve the accuracy of experimental data.

[0025] The advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] Figure 1 This is one of the structural schematic diagrams of the triaxial pulsed shock wave rock fracturing experimental system provided in an embodiment of the present invention.

[0027] Figure 2 This is the second schematic diagram of the structure of the triaxial pulsed shock wave rock fracturing experimental system provided in the embodiment of the present invention.

[0028] Figure 3 The third schematic diagram of the triaxial pulsed shock wave rock fracturing experimental system provided in the embodiment of the present invention.

[0029] Figure 4 The fourth schematic diagram of the triaxial pulsed shock wave rock fracturing experimental system provided in the embodiments of the present invention.

[0030] Figure 5 The fifth schematic diagram of the triaxial pulsed shock wave rock fracturing experimental system provided in the embodiments of the present invention.

[0031] Figure 6This is the sixth schematic diagram of the structure of the triaxial pulsed shock wave rock fracturing experimental system provided in the embodiments of the present invention.

[0032] Figure 7 The seventh schematic diagram of the structure of the triaxial pulsed shock wave rock fracturing experimental system provided in the embodiment of the present invention.

[0033] Figure 8 This is the eighth schematic diagram of the structure of the triaxial pulsed shock wave rock fracturing experimental system provided in the embodiments of the present invention.

[0034] Figure 9 The ninth schematic diagram of the structure of the triaxial pulsed shock wave rock fracturing experimental system provided in the embodiment of the present invention.

[0035] Figure 10 The tenth schematic diagram of the structure of the triaxial pulsed shock wave rock fracturing experimental system provided in the embodiment of the present invention.

[0036] Figure 11 This is a schematic diagram of the arrangement of sampling holes provided in an embodiment of the present invention.

[0037] Figure 12 This is one of the schematic diagrams of the large-scale physical model experimental process provided in the embodiments of the present invention.

[0038] Figure 13 This is the second schematic diagram of the experimental process for a large-scale physical model provided in an embodiment of the present invention.

[0039] Reference numerals: 1. Rock sample; 2. Base; 21. Slide groove; 22. Rectangular groove; 3. Circumferential loading mechanism; 31. Annular frame; 32. First horizontal force application device; 33. Second horizontal force application device; 34. Horizontal force application plate; 35. Loading space; 36. Bearing body; 4. Vertical loading mechanism; 41. Moving frame; 411. Moving wheel; 412. Stepped hole; 42. Vertical force application device; 43. Vertical force application plate; 431. Through hole; 5. Rock displacement Mechanism; 51. Support plate; 52. Frame lifting device; 53. Hanging ring; 54. Support plate lifting device; 541. Ball bearing; 55. Bearing plate; 56. Telescopic device; 6. Shock wave generator; 61. Fixing ring; 62. Window; 7. Hoisting mechanism; 8. Fixing rope; 9. Well shaft; 10. Sampling hole; 11. Casting template; 12. Casting space; 13. Pressure sensor; 14. Abutment plate; 15. Force transmission plate; 16. Electric heating component; 17. Insulation layer. Detailed Implementation

[0040] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0041] like Figures 1 to 10As shown, this embodiment of the invention provides a triaxial pulsed shock wave fracturing rock experimental system, including: a rock sample 1, a base 2, a circumferential loading mechanism 3, a vertical loading mechanism 4, a rock displacement mechanism 5, a shock wave generator 6, a wellbore 9, a pressure sensor 13, and an electric heating assembly 16. The rock sample 1 is mounted on the rock displacement mechanism 5. The circumferential loading mechanism 3 is vertically mounted on the top of the base 2. The vertical loading mechanism 4 and the rock displacement mechanism 5 are both slidably mounted on the top of the base 2. The circumferential loading mechanism 3 surrounds the periphery of the rock sample 1. The vertical loading mechanism 4 is located above the rock sample 1. The top of the shock wave generator 6 is mounted on the vertical loading mechanism 4. The bottom of the shock wave generator 6 and the wellbore 9 are both installed in the rock sample 1. The wellbore 9 is located below the shock wave generator 6. The pressure sensor 13 and the electric heating assembly 16 are installed at the output ends of both the circumferential loading mechanism 3 and the vertical loading mechanism 4.

[0042] The beneficial effects of adopting the technical solution of this invention are as follows: By setting a circumferential loading mechanism, horizontal stress can be applied to the rock sample; by setting a vertical loading mechanism, vertical stress can be applied to the rock sample, thereby realizing a true triaxial stress environment. The vertical loading mechanism is movable, facilitating the placement and removal of the rock sample. The rock displacement mechanism assists the staff in transporting the rock sample and moving it to a set position for successful stress loading. It is suitable for large-volume rocks and can simulate the shock wave fracturing reservoir process under real formation environments (high temperature, high pressure) and wellbore conditions (casing, cementing, perforation). It facilitates the observation of the propagation law of rock fractures caused by pulsed controllable shock wave fracturing, enabling large-scale rock samples (2m×2m×1m) to undergo pulsed controllable shock wave fracturing rock physics simulation experiments under near-formation true triaxial stress conditions, achieving organic unity between indoor experimental conditions and field construction parameters. The structure is reasonably designed, easy to operate, and highly safe, greatly improving the efficiency of the experimental process and providing accurate experimental results.

[0043] Figure 1 The image shows the state of the rock sample being hoisted into the loading space. Figure 2 The image shows the state of the ring frame before the experiment was lifted. Figure 3 The image shows the state when the rock sample is pushed into contact with the support structure. Figure 4 The image shows the state after the casting template is installed. Figure 5 This illustrates the experimental state of controlled shock wave rock fracturing in a simulated geological environment. Figure 6 The image shows the state of the ring frame after the experiment when it was lifted. Figure 7 The diagram shows the state in which the telescopic device pushes the rock sample to the center of the loading space. Figure 8 The structure of the base and the circumferential loading mechanism is shown. Figure 9The installation structure of the vertical loading mechanism is shown. Figure 10 The structure of the pressure sensor, the contact plate, and the force transmission plate is shown.

[0044] The present invention provides a triaxial pulsed shock wave rock fracturing experimental system, which can be a large-size true triaxial pulsed controllable shock wave rock fracturing experimental system. The system includes a base 2, a circumferential loading mechanism 3, a vertical loading mechanism 4, a shock wave fracturing mechanism, and a rock displacement mechanism 5.

[0045] The vertical loading mechanism 4 includes a movable frame 41, a vertical force application device 42, and a vertical force application plate 43.

[0046] The movable frame 41 has an n-shaped cross-section. The lower end of the movable frame 41 is engaged with a groove 21 on the base 2, forming a sliding connection between them. An installation space is created between the movable frame 41 and the base 2, which is then fixedly installed. Grooves 21 are provided on both the left and right sides of the base 2. The grooves 21 have an L-shaped cross-section, as does the lower end of the movable frame 41. A movable wheel 411 is provided at the lower end of the movable frame 41, and the wheel 411 engages with the bottom surface of the groove 21. This structural design of the groove 21 and the lower end of the movable frame 41 not only enables the movable frame 41 to move but also facilitates the application of vertical stress to the rock sample 1. When applying vertical stress, the upper surface of the lower end of the movable frame 41 abuts against the top wall of the groove 21. The movable wheel 411 at the lower end of the movable frame 41 facilitates its movement.

[0047] A vertical force-applying device 42 is installed on the upper part of the movable frame 41, and a vertical force-applying plate 43 is installed at the force-applying end of the vertical force-applying device 42. The n-shaped movable frame 41 can accommodate the circumferential loading mechanism 3, and the movable frame 41 facilitates the placement and removal of the rock sample 1. The lower end of the movable frame 41 is engaged with the base 2, so the vertical force-applying device 42 can apply vertical stress to the rock sample 1 on the base 2 through the vertical force-applying plate 43.

[0048] The circumferential loading mechanism 3 includes a ring frame 31, a first horizontal force application device 32, a second horizontal force application device 33, and a horizontal force application plate 34.

[0049] An annular frame 31 is mounted on the upper surface of the base 2 and located within the installation space. A loading space 35 is centrally located on the annular frame 31, extending through both its upper and lower ends. The loading space 35 is a cubic structure. A first horizontal force-applying device 32 and a second horizontal force-applying device 33 are respectively mounted on two adjacent side walls of the annular frame 31. Horizontal force-applying plates 34 are mounted on the force-applying ends of both devices. The other two side walls of the annular frame 31 serve as load-bearing bodies 36. By setting the first horizontal force-applying device 32, the second horizontal force-applying device 33, and the two load-bearing bodies 36, horizontal stress can be applied to the rock sample 1 on the base 2, avoiding the structural complexity associated with setting four force-applying devices. The annular frame 31 is placed on the base 2. To ensure the stability of the annular frame 31, a fixing mechanism can be used to temporarily fix the annular frame 31 and the movable frame 41 during stress loading. The first horizontal force-applying device 32, the second horizontal force-applying device 33, and the vertical force-applying device 42 each include one or more hydraulic pressurization components.

[0050] Both the horizontal force-applying plate 34 and the vertical force-applying plate 43 include a pressure sensor 13, and an abutment plate 14 and a force-transmitting plate 15 spaced apart. The pressure sensor 13 is located between the abutment plate 14 and the force-transmitting plate 15, with the abutment plate 14 closer to the true triaxial stress simulation space. The pressure sensor 13 is used to monitor the stress magnitude in real time. An electric heating component 16 and a heat insulation layer 17 are respectively provided on both sides inside the abutment plate 14, with the heat insulation layer 17 closer to the pressure sensor 13. The electric heating component 16 can heat the rock sample 1, thereby simulating the temperature environment of deep strata. Electric heating components 16 can also be installed inside the load-bearing plate 55 and the support plate 51 to uniformly heat the rock sample 1 and improve the heating effect.

[0051] The rock displacement mechanism 5 includes a support plate 51, a frame lifting device 52, a support plate lifting device 54, a hanging ring 53, a load-bearing plate 55, a telescopic device 56, and a support plate lifting device 54.

[0052] A support plate 51 is disposed within a rectangular groove 22 on the upper surface of the base 2, with the upper surface of the support plate 51 flush with the upper surface of the base 2. Multiple mounting grooves are circumferentially arranged on the upper surface of the support plate 51, and hanging rings 53 are disposed within these grooves. The rectangular groove 22 facilitates the movement of the support plate 51, and after movement, the upper surface of the support plate 51 remains flush with the upper surface of the base 2, thus not affecting stress loading. The hanging rings 53 are disposed within the mounting grooves, therefore they do not affect the placement of the rock sample 1, nor do they interfere with the annular frame 31.

[0053] The rectangular groove 22 extends circumferentially to the bottom of the annular frame 31. Specifically, the rectangular groove 22 extends circumferentially to the bottom of the bearing 36, while the other side of the annular frame 31 does not extend. In actual use, the area of ​​the support plate 51 is larger than the bottom area of ​​the rock sample 1, which facilitates the fixing and hoisting of the rock sample 1. The extra part of the support plate 51 can be accommodated in the rectangular groove 22 below the annular frame 31, which allows the rock sample 1 and the bearing 36 to abut against each other, facilitating the application of horizontal stress.

[0054] A frame lifting device 52 is installed circumferentially on the base 2, and its telescopic end is connected to the lower surface of the annular frame 31. The frame lifting device 52 is used to lift the annular frame 31, thereby facilitating the movement of the support plate 51 and its insertion into the lower part of the annular frame 31. The frame lifting device 52 employs a hydraulic lifting assembly.

[0055] Both support bodies 36 are equipped with telescopic devices 56. A load-bearing plate 55 is installed on the telescopic end of each telescopic device 56. One side of the load-bearing plate 55 is used to abut against the support body 36, and the other side of the load-bearing plate 55 is close to the true triaxial stress simulation space. The telescopic device 56 uses a hydraulic telescopic assembly. The telescopic device 56 can push the rock sample 1 to move via the load-bearing plate 55, thereby achieving the purpose of uniform force application.

[0056] The support plate lifting device 54 is installed at the center of the upper surface of the base 2. A ball bearing 541 is installed on the telescopic end of the support plate lifting device 54, and the ball bearing 541 is located in a spherical cavity at the end of the telescopic end. The ball bearing 541 is used to engage with the lower surface of the support plate 51. The support plate lifting device 54 uses a hydraulic telescopic assembly, and the ball bearing 541 is made of steel balls. The ball bearing 541 enables the support plate 51 to move in all directions and has high strength. The support plate lifting device 54 can lift the rock sample 1 and the support plate 51 together, allowing the support plate 51 to move on the ball bearing 541, thereby reducing the friction during the movement of the support plate 51 and avoiding the problem of the rock sample 1 being too large to handle.

[0057] The shock wave fracturing mechanism includes an electrically connected shock wave generator 6 and a controller. The shock wave generator 6 is detachably mounted on the movable frame 41. The structure and control method of the shock wave generator 6 and the controller are existing technologies and will not be described further in this embodiment.

[0058] A retaining ring 61 is circumferentially installed on the upper end of the shock wave generator 6.

[0059] The upper part of the movable frame 41 is provided with a stepped hole 412, and the center of the vertical force-applying plate 43 is provided with a through hole 431. The through hole 431 and the stepped hole 412 are coaxially arranged. The lower end of the shock wave generator 6 passes through the stepped hole 412 and the through hole 431 in sequence, and the fixing ring 61 is snapped into the step of the stepped hole 412. The stepped hole 412 and the through hole 431 allow the shock wave generator 6 to pass through, thereby facilitating the replacement of the metal wire or energy bar of the shock wave generator 6 by the staff. The shock wave generator 6 can be installed by the hoisting mechanism 7 and temporarily fixed by the fixing ring 61 and the movable frame 41.

[0060] A true triaxial stress simulation space with a cubic structure is formed between the vertical force-applying plate 43, two horizontal force-applying plates 34, two load-bearing bodies 36, and the support plate 51. A window 62 for the shock wave to pass through is provided at the lower end of the shock wave generator 6, located within the true triaxial stress simulation space. The true triaxial stress simulation space is used to place the rock sample 1, and the lower end of the shock wave generator 6 extends into the wellbore 9 of the rock sample 1. This invention requires applying a stress of 35–65 MPa to the rock sample 1; therefore, all load-bearing components are made of steel plates and a steel structural frame to ensure structural stability during the experiment.

[0061] A hoisting mechanism 7 is installed above the base 2. The lower end of the hoisting rope of the hoisting mechanism 7 is used to engage with the hanging ring 53, and both ends of the fixing rope 8 are used to engage with the hanging ring 53. The hoisting mechanism 7 is used to hoist the rock sample 1 in and out. The hoisting mechanism 7 can be in the form of an overhead crane or a hoist. The fixing rope 8 can fix the rock sample 1 and the support plate 51.

[0062] like Figures 1 to 10 As shown, the vertical loading mechanism 4 further includes: a movable frame 41, a vertical force application device 42, and a vertical force application plate 43. The movable frame 41 has an overall n-shaped structure. The top of the base 2 is provided with a sliding groove 21. The bottom of the movable frame 41 is slidably installed in the sliding groove 21. The tops of the vertical force application device 42 and the shock wave generator 6 are both installed on the top of the movable frame 41. The vertical force application plate 43 is installed on the vertical force application device 42. The vertical force application plate 43 is located above the rock sample 1. The pressure sensor 13 and the electric heating assembly 16 are installed on the vertical force application plate 43.

[0063] The beneficial effects of adopting the above-mentioned further technical solution are: the n-shaped movable frame can accommodate the circumferential loading mechanism, and the movable frame of the vertical loading mechanism can move, thereby facilitating the placement and removal of rock samples. An installation space is formed between the movable frame and the base. The structure of the chute and the lower end of the movable frame not only enables the movable frame to move, but also smoothly applies vertical stress to the rock sample. When applying vertical stress, the upper surface of the lower end of the movable frame abuts against the top wall of the chute.

[0064] like Figures 1 to 10 As shown, the bottom of the movable frame 41 is an L-shaped structure, the slide groove 21 is an L-shaped slide groove, and the bottom end of the movable frame 41 is provided with a movable wheel 411.

[0065] The beneficial effects of adopting the above-mentioned further technical solution are: the structural design of the chute and the lower end of the moving frame not only enables the moving frame to move, but also allows for the smooth application of vertical stress to the rock sample. When applying vertical stress, the upper surface of the lower end of the moving frame abuts against the top wall of the chute. The moving wheel 1 at the lower end of the moving frame facilitates the movement of the moving frame.

[0066] like Figures 1 to 10 As shown, the circumferential loading mechanism 3 further includes: an annular frame 31, a first horizontal force-applying device 32, a second horizontal force-applying device 33, and a horizontal force-applying plate 34. The annular frame 31 is vertically mounted on the top of the base 2. The annular frame 31 is located in the vertical loading mechanism 4. The annular frame 31 is a loading space 35 with a cubic structure and open at both ends. The first horizontal force-applying device 32 and the second horizontal force-applying device 33 are installed one-to-one on two adjacent first inner sidewalls of the annular frame 31. The output ends of the first horizontal force-applying device 32 and the second horizontal force-applying device 33 are both equipped with the horizontal force-applying plate 34. The pressure sensor 13 and the electric heating assembly 16 are installed on the horizontal force-applying plate 34. The two adjacent second inner sidewalls of the annular frame 31 are both load-bearing bodies 36.

[0067] The beneficial effect of adopting the above-mentioned further technical solution is that by setting up a first horizontal force application device, a second horizontal force application device, and two bearing bodies, the horizontal stress on the rock sample on the base can be applied, avoiding the structural complexity problem of needing to set up four force application devices.

[0068] like Figures 1 to 10 As shown, the horizontal force-applying plate 34 further includes: an abutment plate 14, a force-transmitting plate 15, and a heat insulation layer 17. The output ends of the first horizontal force-applying device 32 and the second horizontal force-applying device 33 are both equipped with the force-transmitting plate 15. The pressure sensor 13 is installed on the force-transmitting plate 15, and the abutment plate 14 is installed on the pressure sensor 13. The electric heating component 16 and the heat insulation layer 17 are both installed in the abutment plate 14. The heat insulation layer 17 is adjacent to the pressure sensor 13. A casting template 11 is detachably installed on the carrier 36.

[0069] The beneficial effects of adopting the above-mentioned further technical solution are as follows: A pressure sensor is positioned between the abutment plate and the force transmission plate, with the abutment plate closer to the true triaxial stress simulation space. The pressure sensor is used to monitor the stress magnitude in real time. Electric heating components and insulation layers are respectively installed on both sides inside the abutment plate, with the insulation layer closer to the pressure sensor. The electric heating components can heat the rock sample, thereby simulating the temperature environment of deep strata. Electric heating components can also be installed inside the load-bearing plate and the support plate to uniformly heat the rock sample and improve the heating effect.

[0070] like Figures 1 to 10 As shown, the rock displacement mechanism 5 further includes: a support plate 51, a frame lifting device 52, a hanging ring 53, a support plate lifting device 54, a load-bearing plate 55, and a telescopic device 56. The top of the base 2 is provided with a rectangular groove 22, which extends to the bottom of the circumferential loading mechanism 3. The rock sample 1 is installed on the support plate 51, which is slidably installed in the rectangular groove 22. The top of the support plate 51 is flush with the top of the base 2. The top of the support plate 51 is provided with an installation groove, in which the hanging ring 53 is installed. The frame lifting device 52 is installed on the top of the base 2, and its output end is connected to the circumferential loading mechanism 3. The telescopic device 56 is installed on each of the two adjacent second inner sidewalls of the circumferential loading mechanism 3. The load-bearing plate 55 is installed on the output end of the telescopic device 56. The support plate lifting device 54 is installed at the middle of the top of the base 2, and its output end abuts against the support plate 51.

[0071] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: The rock displacement mechanism can assist workers in transferring rock samples and moving them to a set position for smooth stress loading. The rectangular groove facilitates the movement of the support plate, and after movement, the upper surface of the support plate is flush with the upper surface of the base, thus not affecting stress loading. The hanging ring is set in the installation groove, so it will not affect the placement of the rock sample or interfere with the annular frame. The rectangular groove extends circumferentially to the bottom of the carrier, while the other side of the annular frame does not extend. In actual use, the area of ​​the support plate is larger than the bottom area of ​​the rock sample, which facilitates the fixing and hoisting of the rock sample. The excess part of the support plate can be accommodated in the rectangular groove below the annular frame, allowing the rock sample to contact the carrier and facilitating the loading of horizontal stress. The frame lifting device is used to lift the annular frame, making it easier for the support plate to be inserted into the lower part of the annular frame after movement. The telescopic device can push the rock sample to move through the load-bearing plate, thereby achieving the purpose of uniform force application.

[0072] like Figures 1 to 10As shown, the output end of the support plate lifting device 54 is provided with a spherical cavity, and a ball bearing 541 is provided in the spherical cavity, the ball bearing 541 abutting against the support plate 51.

[0073] The beneficial effects of adopting the above-mentioned further technical solution are: the ball bearings enable the support plate to move in all directions and have high strength. The support plate lifting device can lift the rock sample and the support plate together, allowing the support plate to move on the ball bearings, thereby reducing the friction during the movement of the support plate and avoiding the problem of the rock sample being too large to handle.

[0074] like Figures 1 to 10 As shown, further, a fixing ring 61 is installed on the top of the shock wave generator 6, a stepped hole 412 is provided on the top of the vertical loading mechanism 4, the fixing ring 61 is installed in the stepped hole 412, and a window 62 for the shock wave to pass through is provided at the bottom of the shock wave generator 6, the window 62 being located in the rock sample 1.

[0075] The advantages of adopting the above-mentioned further technical solution are: it facilitates the replacement of the metal wires or energy bars of the shock wave generator by the staff. The shock wave generator can be installed by a hoisting mechanism and temporarily fixed by a fixing ring and a movable frame. The lower end of the shock wave generator is provided with a window for the shock wave to pass through, and the window is located in the true triaxial stress simulation space.

[0076] like Figures 1 to 10 As shown, a hoisting mechanism 7 is further provided above the base 2. The hoisting rope of the hoisting mechanism 7 is connected to the rock displacement mechanism 5. The rock sample 1 is installed on the rock displacement mechanism 5 by a fixing rope 8.

[0077] The beneficial effects of adopting the above-mentioned further technical solutions are: the rock displacement mechanism and the hoisting mechanism can assist workers in transferring rock samples and moving them to a set position for smooth stress loading. The lower end of the hoisting rope of the hoisting mechanism is used to engage with the hanging ring, and both ends of the fixing rope are used to engage with the hanging ring. The hoisting mechanism is used for hoisting the rock sample in and out, and can be in the form of an overhead crane or a hoist. The fixing rope can secure the rock sample and the support plate.

[0078] like Figures 1 to 10 As shown, the rock sample 1 has a cubic structure, the well shaft 9 has an inner diameter of 127 mm, and the wall thickness of the well shaft 9 is 10 mm.

[0079] The beneficial effect of adopting the above-mentioned further technical solutions is to improve the accuracy of experimental data.

[0080] The experimental method based on the triaxial pulsed shock wave fracturing rock experimental system provided by this invention can be as follows:

[0081] Rock sample 1 was collected, and a hole was drilled in rock sample 1 to take samples. Then, rock sample 1 was pretreated to form a cubic structure.

[0082] Natural outcrop rock sample 1 can be used, with lithology including conglomerate, sandstone, and mudstone / shale, etc. The length, width, and height dimensions of rock sample 1 are all greater than 1m. After pretreatment, rock sample 1 forms a cubic structure with a smooth surface.

[0083] Drill a pre-drilled hole in rock sample 1 and install wellbore 9 inside the pre-drilled hole.

[0084] Then cementing is carried out to ensure the stability and safety of wellbore 9.

[0085] Wellbore 9 is made of TP110H material, with an inner diameter of 127mm and a wall thickness of 10mm. The perforation scheme adopts a single-cluster spiral perforation with a perforation diameter of 10mm, a perforation depth of 30cm, a phase angle of 120°, and a perforation spacing of 6cm, consisting of 3 perforations per cluster. A sealing structure is installed at the end of the casing, and the bottom hole pressure resistance must reach 100MPa.

[0086] Rock sample 1 is placed in the center of support plate 51. Support plate 51 is located in rectangular groove 22 on the upper surface of base 2 and in loading space 35 at the center of ring frame 31. Loading space 35 is a cubic structure.

[0087] The control frame lifting device 52 lifts the annular frame 31 away from the base 2, and then the control support plate lifting device 54 lifts the support plate 51 away from the base 2, so that the upper surface of the support plate 51 and the lower surface of the annular frame 31 are spaced apart.

[0088] Control the first horizontal force application device 32 and the second horizontal force application device 33 on the two adjacent side walls of the ring frame 31, so that the horizontal force application plate 34 at its force application end pushes the rock sample 1 and the support plate 51 together toward the bearing 36 of the other two side walls of the ring frame 31, until the two side walls of the rock sample 1 abut against the two bearings 36 respectively.

[0089] The first horizontal force application device 32 and the second horizontal force application device 33 serve as both stress loading devices and devices for moving the rock sample 1.

[0090] The control plate lifting device 54 lowers the support plate 51 to abut against the base 2, and the control frame lifting device 52 lowers the annular frame 31 to abut against the base 2 and the support plate 51.

[0091] Control the movement of the moving frame 41 so that the vertical force application device 42 on the upper part of the moving frame 41 is directly above the rock sample 1. Control the movement of the vertical force application plate 43 at the force application end of the vertical force application device 42 so that the vertical force application plate 43 and the upper surface of the rock sample 1 come into contact.

[0092] Control the first horizontal force application device 32 and the second horizontal force application device 33 so that the horizontal force application plate 34 at the force application end applies horizontal stress to the rock sample 1 until the set principal stress range is reached.

[0093] Control the vertical force application device 42 to apply vertical stress to the rock sample 1 until the set vertical stress range is reached.

[0094] Before pressurization, ensure that the horizontal force-applying plate 34 and the vertical force-applying plate 43 are completely in contact with the surface of rock sample 1, with no debris in between. Before applying stress, conduct a safety inspection of the pressurization part and rock sample 1, observing whether there are cracks on the surface of rock sample 1 and whether the surface of the force-applying device is smooth. Clean the area near the pressurization part. After confirming that everything is normal, designate a high-pressure operation zone with a radius of 50m around the pressurization part, set up a warning line, and prohibit personnel from entering during the pressurization process. During the stress application process, the pressurization rate should be strictly controlled below 1MPa / min, and the state of rock sample 1 should be monitored in real time using a fracturing monitoring device (which can be a stress strain gauge). The stress in the horizontal direction is 55-65MPa, and the stress in the vertical direction is 35-45MPa.

[0095] Fracturing fluid is injected into the wellbore 9, and the shock wave generator 6 is placed inside the wellbore 9, with the window 62 of the shock wave generator 6 aligned with the shock wave operation point.

[0096] Repeat the following steps until the crack breaks through the boundary of rock sample 1 and no new cracks are generated: use shock wave generator 6 to perform shock wave operation on rock sample 1 to induce cracking. After setting the number of times, record the cracking radius and crack propagation morphology, and then drill holes in rock sample 1 to take samples.

[0097] Sampling principle: Use a rotation angle of 60° and a sampling interval of 30cm to uniformly sample at different locations at different distances from the wellbore; Sampling requirements: Drill one plunger sample at each sampling location before and after the experiment.

[0098] The sampling results were compared and analyzed to obtain the changes in porosity and permeability parameters and mechanical parameters of rock sample 1. Finally, the changes in rock physical properties and rock mechanical parameters before and after the shock wave were compared and analyzed.

[0099] This invention can also observe the morphology and distribution of cracks in each rock sample under different operation times, and compare and analyze the changes in rock mechanical parameters during the cracking process induced by pulsed controllable shock wave.

[0100] Before and after the experiment, multiple samples were taken from the casing to test its compressive and tensile strength. The performance parameters of the casing before and after the experiment were compared to analyze whether the pulsed controlled shock wave caused damage to the casing.

[0101] Method for determining porosity and permeability parameters: Multiple samples were taken from rock sample 1 before and after the fracturing experiment. Rock columns were prepared by wire cutting. The changes in porosity and permeability parameters of rock sample 1 were compared and analyzed. The experimental operation procedure refers to "GB / T29172-2012 Core Analysis Method".

[0102] Rock mechanical property testing: Multiple samples were taken from rock sample 1 before and after the fracturing experiment. Rock columns were prepared by wire cutting. Mechanical parameters such as compressive strength, tensile strength and shear strength were tested. The changes in rock mechanical parameters of rock sample 1 were compared and analyzed. The experimental operation procedure referred to "DZ / T0276.20-2015 Test Procedure for Physical and Mechanical Properties of Rock".

[0103] Experimental analysis was conducted on the metallic properties of the casing before and after the impact. Samples were taken using metal cutting methods, and compressive strength and tensile strength tests were performed. This was to determine the impact of shock wave-induced fracturing on the metallic properties of the casing, whether there was any damage to the casing, and thus to provide a basis for the selection of subsequent casings.

[0104] Multiple samples were taken from the casing before and after the cracking to analyze the changes in tensile properties of the casing before and after cracking. The test procedure was carried out in accordance with GB / T228.1-2021 Metallic Materials - Tensile Testing - Part 1: Room Temperature Test Method.

[0105] like Figure 12 As shown, the process includes large rock sample preparation, small plunger processing, actual wellbore construction, stress loading, impact fracturing experiment, post-impact sampling and testing, and fracturing effect analysis.

[0106] like Figure 13 As shown, the steps are as follows: 1. Large-scale model experiment; 2. Conglomerate, sandstone, and shale; 3. Experiments with and without confining pressure; 4. Drilling rock sample columns, testing of rock physical properties and mechanical parameters, and casing strength testing; 5. Fracture morphology description and fracture reconstruction; 6. Analysis of the effect of shock wave-induced fracture of rock samples; 7. Simulation calculation of effective action distance; 8. Numerical simulation; 9. Simulation software CDEM; 10. Establishment of mathematical model; 11. Homogeneous strength simulation and random strength simulation; 12. Simulation parameter correction; Proceed to step 7.

[0107] Key steps and experimental scheme of large-scale model experiment: Large rock sample preparation: Processing and preparing large-sized (2m×2m×1m) conglomerate, sandstone, and shale outcrop samples; Wellbore construction: Using real casing (TP125V, pressure resistant 125MPa), single-cluster helical drilling with 3 holes and a hole spacing of 6cm; Stress loading: Applying horizontal biaxial stress of 20MPa and 10MPa respectively; Impact test: High-energy impact test, pausing after every 3 cycles to observe, describe, and record the fracturing effect on the rock sample; In-pressure monitoring: 3 types of staining agents (main monitoring) + pre-embedded stress blocks and surface-mounted strain gauges (auxiliary monitoring); Small plunger processing: Drilling small plungers with a diameter of 2.5cm and a height of 5cm before and after the impact test, evenly distributed at different locations from the wellbore; Fracture characterization: Dissecting the rock sample along the fracture direction, measuring fracture size, density, and other parameters, and performing mathematical modeling.

[0108] In this embodiment, after each sampling, a solidifying material is injected into the sampling hole 10 to seal it, so as to avoid interfering with the subsequent crack propagation. The solidifying material can be epoxy resin.

[0109] like Figure 11 As shown, in this embodiment, the multiple sampling holes 10 for each sampling are all located on the same straight line, and the straight line formed by multiple samplings is evenly distributed around the reserved hole.

[0110] In each sampling, the distance between two adjacent sampling holes 10 is 25cm to 35cm, and the distance between any sampling hole 10 and the reserved hole is greater than 25cm.

[0111] This sampling method can obtain more reasonable comparison results, thereby improving the accuracy of the experiment.

[0112] In this embodiment, a dye is added to the fracturing fluid, and the fracturing fluid after dyeing is used to calibrate the fracture propagation.

[0113] This invention can use different colored dyes to calibrate the crack propagation at different stages, and perform 3D modeling of crack morphology based on rock segmentation.

[0114] The present invention can also employ a physical model method: by injecting a solidifiable fluid, such as epoxy resin, paraffin, or low-melting-point metal, into the wellbore 9, a physical model of the fracture morphology can be obtained.

[0115] The present invention can also employ radar monitoring: a ground-penetrating radar is used to scan rock sample 1, and the location and morphology of the crack are determined based on the time difference and position difference of electromagnetic waves propagating inside rock sample 1, and the crack morphology is described based on the signal reception data.

[0116] This invention also employs a numerical simulation method: finite difference software or finite element programs are used for simulation. A model is established based on actual engineering geological parameters, including four groups: borehole, casing (including perforation), cement sheath, and rock strata. The numerical simulation consists of three parts: first, simulation of indoor model tests; second, site-scale model simulation considering casing, perforation, and cement sheath; and finally, simulation of similar test models. The numerical simulation results guide similar model tests, which are then used to verify and refine the numerical simulation.

[0117] In this embodiment, the pretreatment of rock sample 1 includes the following steps:

[0118] The edges of rock sample 1 were cut using a cutting machine to make it approach a cubic structure. The surface was made as smooth as possible.

[0119] Rock sample 1 is placed on support plate 51, and rock sample 1 and support plate 51 are fixed by fixing rope 8. Rock sample 1 and support plate 51 are hoisted together to the center of ring frame 31 by hoisting mechanism 7, so that support plate 51 is located in rectangular groove 22.

[0120] The control frame lifting device 52 lifts the annular frame 31 away from the base 2, and then the control support plate lifting device 54 lifts the support plate 51 away from the base 2, so that the upper surface of the support plate 51 and the lower surface of the annular frame 31 are spaced apart.

[0121] Casting templates 11 are installed on the surfaces of the two carriers 36. The first horizontal force application device 32 and the second horizontal force application device 33 are controlled to push the rock sample 1 and the support plate 51 together towards the carrier 36 until the two side walls of the rock sample 1 abut against the two casting templates 11 respectively.

[0122] The control plate lifting device 54 lowers the support plate 51 to abut against the base 2, and the control frame lifting device 52 lowers the annular frame 31 to abut against the base 2 and the support plate 51.

[0123] Replace the horizontal force-applying plates 34 at the force-applying ends of the first horizontal force-applying device 32 and the second horizontal force-applying device 33 with casting templates 11, and control the first horizontal force-applying device 32 and the second horizontal force-applying device 33 to make the two casting templates 11 abut against the other two side walls of the rock sample 1. At this time, the support plate 51 and the four casting templates 11 form a semi-enclosed structure, and the space between the semi-enclosed structure and the rock sample 1 is the casting space 12.

[0124] Cement is poured into the pouring space 12. After the cement has solidified, the pouring template 11 is removed, the surface of the rock sample 1 is ground smooth to form a cubic structure, and then the site is cleaned.

[0125] Conventional methods include directly cutting the rock sample 1 into a cubic structure using a cutting machine, which requires sophisticated equipment. Another method involves directly coating the sample with cement to improve flatness. However, the rock sample 1 in this invention is large, and conventional methods are inefficient and ineffective. Therefore, using a stress loading system to pour cement to form a cubic structure not only simplifies the operation and saves on equipment, but also eliminates the need for repeatedly moving the rock sample 1.

[0126] In this embodiment, a ball bearing 541 is installed on the telescopic end of the support plate lifting device 54. The ball bearing 541 is disposed in the spherical cavity at the end of the telescopic end. When the support plate lifting device 54 lifts the support plate 51 away from the base 2, the ball bearing 541 and the lower surface of the support plate 51 abut against each other.

[0127] When the support plate 51 moves, the ball bearing 541 rolls relative to the support plate 51.

[0128] In this embodiment, when the rock sample 1 is moved from one side of the support body 36 to the center of the annular frame 31, the frame lifting device 52 is controlled to lift the annular frame 31 away from the base 2, and then the support plate lifting device 54 is controlled to lift the support plate 51 away from the base 2, so that the upper surface of the support plate 51 and the lower surface of the annular frame 31 are spaced apart.

[0129] Control the telescopic device 56 on the carrier 36 to push the rock sample 1 until the rock sample 1 and the carrier 36 move together to the center of the annular frame 31.

[0130] After the experiment is completed, the rock sample 1 and the carrier 36 can be moved together to the center of the ring frame 31 by following this operation method, and then the rock sample 1 and the carrier 36 can be lifted away together by the hoisting mechanism 7.

[0131] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A triaxial pulsed shock wave-induced rock fracturing experimental system, characterized in that, include: The components include a rock sample (1), a base (2), a circumferential loading mechanism (3), a vertical loading mechanism (4), a rock displacement mechanism (5), a shock wave generator (6), a wellbore (9), a pressure sensor (13), and an electric heating assembly (16). The rock sample (1) is mounted on the rock displacement mechanism (5). The circumferential loading mechanism (3) is vertically mounted on the top of the base (2). The vertical loading mechanism (4) and the rock displacement mechanism (5) are both slidably mounted on the top of the base (2). The circumferential loading mechanism (3) surrounds the periphery of the rock sample (1). The vertical loading mechanism (4) is located above the rock sample (1). The top of the shock wave generator (6) is mounted on the vertical loading mechanism (4). The bottom of the shock wave generator (6) and the wellbore (9) are both installed in the rock sample (1). The wellbore (9) is located below the shock wave generator (6). The output ends of the circumferential loading mechanism (3) and the vertical loading mechanism (4) are both equipped with the pressure sensor (13) and the electric heating assembly (16). The vertical loading mechanism (4) includes: a moving frame (41), a vertical force application device (42), and a vertical force application plate (43). The moving frame (41) is generally n-shaped. The top of the base (2) is provided with a groove (21). The bottom of the moving frame (41) is slidably installed in the groove (21). The vertical force application device (42) and the shock wave generator (6) are both installed in the rock sample (1). The top of 6) is installed on the top of the movable frame (41), the vertical force plate (43) is installed on the vertical force device (42), the vertical force plate (43) is located above the rock sample (1), and the pressure sensor (13) and the electric heating component (16) are installed on the vertical force plate (43); the bottom of the movable frame (41) is an L-shaped structure, the slide groove (21) is an L-shaped slide groove, and the bottom end of the movable frame (41) is provided with a moving wheel (411); the circumferential loading mechanism (3) includes: a ring frame (31), a first horizontal force device (32), a second horizontal force device (33) and a horizontal force plate (34), the ring frame (31) is vertically and vertically installed on the top of the movable frame (41); the top of 6) is installed on the top of the movable frame (41), the vertical force plate (43 ... At the top of the base (2), the annular frame (31) is located in the vertical loading mechanism (4). The annular frame (31) is an open structure with two ends of a loading space (35) with a cubic structure. The first horizontal force application device (32) and the second horizontal force application device (33) are installed on the two adjacent first inner sidewalls of the annular frame (31). The output ends of the first horizontal force application device (32) and the second horizontal force application device (33) are all equipped with the horizontal force application plate (34). The pressure sensor (13) and the electric heating component (16) are installed on the horizontal force application plate (34). The two adjacent second inner sidewalls of the annular frame (31) are all load-bearing bodies (36).The rock displacement mechanism (5) includes: a support plate (51), a frame lifting device (52), a hanging ring (53), a support plate lifting device (54), a load-bearing plate (55), and a telescopic device (56). The base (2) has a rectangular groove (22) at its top, which extends to the bottom of the circumferential loading mechanism (3). The rock sample (1) is installed on the support plate (51), which is slidably installed in the rectangular groove (22). The top of the support plate (51) is flush with the top of the base (2). The top of the support plate (51) is provided with a support plate (51). The mounting slot is in which the hanging ring (53) is installed. The frame lifting device (52) is installed on the top of the base (2). The output end of the frame lifting device (52) is connected to the circumferential loading mechanism (3). The telescopic device (56) is installed on the two adjacent second inner sidewalls of the circumferential loading mechanism (3). The load-bearing plate (55) is installed on the output end of the telescopic device (56). The support plate lifting device (54) is installed at the top center of the base (2). The output end of the support plate lifting device (54) abuts against the support plate (51).

2. The triaxial pulsed shock wave-induced rock fracturing experimental system according to claim 1, characterized in that, The horizontal force-applying plate (34) includes: an abutment plate (14), a force-transmitting plate (15), and a heat insulation layer (17). The output ends of the first horizontal force-applying device (32) and the second horizontal force-applying device (33) are both equipped with the force-transmitting plate (15). The pressure sensor (13) is installed on the force-transmitting plate (15). The abutment plate (14) is installed on the pressure sensor (13). The electric heating component (16) and the heat insulation layer (17) are both installed in the abutment plate (14). The heat insulation layer (17) is adjacent to the pressure sensor (13). The casting template (11) is detachably installed on the carrier (36).

3. The triaxial pulsed shock wave-induced rock fracturing experimental system according to claim 1, characterized in that, The output end of the support plate lifting device (54) is provided with a spherical cavity, and a ball bearing (541) is provided in the spherical cavity. The ball bearing (541) abuts against the support plate (51).

4. The triaxial pulsed shock wave-induced rock fracturing experimental system according to claim 1, characterized in that, The shock wave generator (6) is equipped with a fixing ring (61) at the top, and the vertical loading mechanism (4) is provided with a step hole (412) at the top. The fixing ring (61) is installed in the step hole (412). The shock wave generator (6) is provided with a window (62) for the shock wave to pass through, and the window (62) is located in the rock sample (1).

5. The triaxial pulsed shock wave-induced rock fracturing experimental system according to claim 1, characterized in that, A hoisting mechanism (7) is provided above the base (2). The hoisting rope of the hoisting mechanism (7) is connected to the rock displacement mechanism (5). The rock sample (1) is installed on the rock displacement mechanism (5) by a fixing rope (8).

6. The triaxial pulsed shock wave-induced rock fracturing experimental system according to claim 1, characterized in that, The rock sample (1) has a cubic structure, the wellbore (9) has an inner diameter of 127 mm and a wall thickness of 10 mm.

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