Test system and method for simulating fracturing of hot dry rock propping agent

Abstract

The invention discloses a test system and method for simulating hot dry rock propping agent fracturing. The system comprises a rock test piece, an injection system, a confining pressure device and an acoustic emission monitoring system, the rock test piece is of a cubic structure, a well hole is formed in the surface of the rock test piece, a sleeve is inserted into the well hole, and one end of the sleeve extends out of the rock test piece from the well hole; the injection system comprises a booster pump, the input end is connected with a plurality of liquid storage boxes, and the output end is connected with the sleeve; a clamping steel frame is arranged in the confining pressure device, and a heating system is arranged on the clamping steel frame; according to the invention, different propping agent fracturing fluids are injected into the rock test piece through the casing pipe on the borehole in different stages by the injection system, the process of propping agent fracturing in the reduction project is truly simulated, the fracturing fluids in different stages can play a role, and the change trend of the fracturing process is visually recorded through the acoustic emission monitoring system, so that the test result is more accurate. The whole experiment system truly restores the hot dry rock fracturing environment of the enhanced geothermal system.

Description

Technical Field

[0001] The invention relates to the technical field of rock fracturing, in particular to a test system and method for simulating hot dry rock proppant fracturing. Background Art

[0002] Hot dry rock reservoirs generally have complex geological conditions. The temperature, stress environment, and physical properties of the rocks will affect the reservoirs. In addition, the permeability of hot dry rock is extremely low. In order to improve the permeability of hot dry rock reservoirs, hydraulic fracturing is mainly used in the development of hot dry rock projects. High-pressure water is injected into the rocks to break the rocks and form new cracks. Flow channels are formed through the cracks, and proppants are used to prevent the cracks in the reservoir from closing to improve the permeability effect.

[0003] Through simulation experiments, we can have a deeper understanding of the various phenomena and problems in the process of hot dry rock fracturing, and provide theoretical support and guidance for actual mining. At present, most of the test systems for simulating hot dry rock proppant fracturing directly inject water into the rock specimens for fracturing and fill the cracks with proppant. During the fracturing of the rock specimens and the filling of proppant, the influence of high temperature and high stress environment on the stability of the rock pore structure is not considered, and only a single proppant is used to support the pore structure at different stages of fracturing. It is difficult to truly simulate the changes in the cracks of rocks at different fracturing stages in a high temperature and high stress environment, and thus it is difficult to truly simulate the distribution of different proppant fracturing fluids in the pore structure for different crack structures at different fracturing stages. Summary of the invention

[0004] The purpose of the present invention is to provide a test system and method for simulating hot dry rock proppant fracturing, which can simulate high temperature, confining pressure and fracturing fluid injection under actual engineering environment requirements for rock specimens of different sizes, so as to analyze rock characteristics.

[0005] The technical solution of the present invention is:

[0006] A test system for simulating hot dry rock proppant fracturing comprises: a rock specimen, which is a cubic structure with primary cracks, wherein a wellbore is opened on one of the surfaces of the rock specimen toward the inside of the rock specimen, wherein a casing is inserted into the wellbore, and one end of the casing extends from the wellbore to the outside of the rock specimen; an injection system, comprising a booster pump, wherein the input end of the booster pump is respectively connected to a plurality of liquid storage tanks through a plurality of pipelines, wherein each pipeline is provided with a pipe valve, wherein each liquid storage tank stores different kinds of proppant fracturing fluids, and the output end of the booster pump is connected to the casing on the rock specimen, so as to provide different proppant fracturing fluids to the inside of the rock specimen at different stages; and the booster pump is a booster self-priming pump, which can draw liquid in the liquid storage tank into the pump, and wherein a flow controller is provided in the booster pump, which can control the injection rate and pressure of the liquid. A confining pressure device is used to apply pressure loading to the rock specimen to create a confining pressure environment. A clamping steel frame is provided inside the confining pressure device. The clamping steel frame is used to clamp and fix the rock specimen, and a heating system is provided on the clamping steel frame to control the temperature of the rock specimen; an acoustic emission monitoring system is used to process and analyze signals of crack generation and expansion of the rock specimen during fracturing, including: an acoustic emission monitor and multiple acoustic emission probes, the multiple acoustic emission probes are connected to the acoustic emission detector, and the acoustic emission probes are set in the original cracks of the rock specimen to measure the appearance and distribution of new cracks during fracturing.

[0007] Furthermore, the borehole diameter on the rock specimen is 10 mm and the depth is 75 mm. The casing in the borehole is a metal casing, and the casing and the borehole are fixed with epoxy resin glue. The casing extends out of the surface of the rock specimen for a section of 10 mm.

[0008] Furthermore, the clamping steel frame is a rectangular steel frame, including a steel frame body and a plurality of electric push rods, the plurality of electric push rods are correspondingly arranged at each vertex of the steel frame body, and the telescopic ends of the electric push rods are all facing the center point of the rectangular steel frame.

[0009] Furthermore, a push rod support block is provided on the end of the telescopic end of each electric push rod.

[0010] Furthermore, the heating system includes: two heaters, both of which are rectangular heaters, which are sequentially mounted on the rock specimen; a temperature sensor for real-time detection of the temperature of the rock specimen; and the temperature sensor is arranged on a surface of the rock specimen away from a surface where a wellbore is located.

[0011] Furthermore, the rectangular heater includes: a rectangular shell, a resistance wire and a heat-resistant layer are arranged inside the rectangular shell, and a detachable connection port is provided at the midpoint of one side of the rectangular shell, and the connection port is located on the front side of the rock specimen.

[0012] Furthermore, the injection system has three liquid storage tanks, which respectively store: distilled water, sand-carrying liquid and displacement liquid.

[0013] The method for conducting a test using the above-mentioned test system for simulating hot dry rock proppant fracturing comprises the following steps:

[0014] S1. Prepare a rock specimen, process the rock specimen into a cubic structure, open a wellbore on the front of the rock specimen, and insert a casing into the wellbore; the processing process of the rock specimen is specifically as follows: symmetrically cut the rock specimen with a rock cutter to obtain a regular 150mm×150mm×150mm cube block, and grind the cut surface of the rock specimen with a rock grinder.

[0015] S2 After that, place the clamping steel frame on the base of the confining pressure device, adjust the electric push rod on the intelligent steel frame according to the size of the specimen, place the rock specimen on the clamping steel frame on the support of the telescopic rod, fix it, connect the heating system to the rock specimen, and install the acoustic emission probe in the original crack of the rock specimen; in S2, when the heating system is connected and fixed, fix the two heaters at a distance of approximately one-third of the length of the rock specimen from the left and right end faces of the rock specimen, and close the connection port to connect the heater and the temperature sensor.

[0016] S3. Heat the rock specimen through the heating system according to the temperature required by the test, and keep it warm after reaching the target temperature; set the heating temperature to 150°C, and keep it warm for 2 hours after reaching the target temperature to ensure that the rock specimen is heated evenly.

[0017] S4. Control different loading heads of the confining pressure device to load the rock specimen according to the load size required by the test; the confining pressure device is connected to the confining pressure controller, and the confining pressure value applied by the loading heads 5-2 at the left and right ends is 2Mpa, and the confining pressure value applied by the upper head is 5Mpa through the confining pressure controller; thereby simulating the ground stress state of the deep rock mass.

[0018] S5. Connect the output end of the booster pump of the injection system to the casing of the rock specimen, set the injection rate of the booster pump according to the test requirements, and inject different proppant fracturing fluids into the rock specimen at different stages.

[0019] S6. The data of the entire test process are collected and recorded by the acoustic emission monitor. After the test is completed, the heater and confining pressure device are turned off and released. When the temperature drops to room temperature, the rock specimens are taken out and placed in a CT scanner to observe and analyze the crack characteristics.

[0020] Furthermore, the proppant fracturing fluid in each stage has the same function as the fracturing fluid in the construction process, and the injection steps of the proppant fracturing fluid in different stages include:

[0021] The pipe valve of the pipeline connecting the liquid storage tank containing distilled water and the booster pump is opened, and the distilled water is injected into the rock specimen to cause cracks.

[0022] After the data stabilizes, close the pipe valve of the liquid storage box containing distilled water, and then open the pipe valve on the pipeline connected to the liquid storage box containing sand-carrying liquid. Control the injection rate of the booster pump according to the test requirements and inject the sand-carrying liquid into the rock specimen.

[0023] After the data stabilizes, close the pipe valve on the pipeline connected to the storage tank containing the sand-carrying fluid, and then open the pipe valve on the pipeline connected to the storage tank containing the displacement fluid. Control the injection rate of the booster pump according to the test requirements, inject the displacement fluid, and bring the proppant in the sand-carrying fluid into the cracks of the rock specimen.

[0024] Furthermore, in order to ensure the safety of the experiment or to compare the injection rate and injection pressure values, the injection pressure was set to 50 MPa and the injection rate was set to 5 ml / min when injecting distilled water; the injection pressure was set to 10 MPa and the injection rate was set to 1 ml / min when injecting sand-carrying fluid; and the injection pressure was set to 20 MPa and the injection rate was set to 5 ml / min when injecting displacement fluid.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The confining pressure device in the experimental system of the present invention is equipped with a heating system, which can apply different pressures and temperatures to the test piece in different directions according to needs through a controller, and simulate a water injection well with a wellbore with a casing for the treatment of the rock test piece, and inject different proppant fracturing fluids into the rock test piece through the casing on the wellbore at different fracturing stages through the injection system, truly simulating the proppant fracturing process in the restoration project, and making the fracturing fluids at different stages play a role. During the entire test process, the changing trend of the fracturing process is intuitively recorded by the acoustic emission monitoring system, and the entire experimental system truly restores the environment of dry hot rock fracturing in the enhanced geothermal system.

[0027] 2. The clamping steel frame in the test system of the present invention is equipped with electric push rods at fixed points. The rock specimens are clamped by multiple electric push rods, which can be suitable for rock specimens of different sizes. The clamping steel frame is set as a cubic frame and is equipped with two rectangular heaters. The rectangular heaters are set on the clamping steel frame and close to the surface of the rock specimen. They are heated by resistance wires, which not only makes the heating more uniform, but also has higher efficiency and reduces errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The injection system structure schematic diagram of the present invention.

[0029] Figure 2 This is a schematic diagram of the structure of the rock specimen after processing according to the present invention.

[0030] Figure 3 It is a schematic diagram of the clamping steel frame structure of the present invention.

[0031] Figure 4 It is a schematic diagram of the structure of the rectangular heater of the present invention.

[0032] Figure 5 It is a schematic structural diagram of the confining pressure device of the present invention.

[0033] Figure 6 It is a schematic diagram of the structure of the rock specimen of the present invention assembled in the loading device.

[0034] Among them, 1. injection system; 1-1. booster pump; 1-2. liquid storage tank; 1-3. water filling port of liquid storage tank; 1-4. pipe valve of liquid storage tank; 1-5. pipeline; 1-6. booster pump base; 1-7. booster pump outlet pipe; 2. rock specimen; 2-1. casing; 3. clamping steel frame; 3-1. steel frame body; 3-2. electric push rod; 3-3. push rod support block; 3-4. layout hole; 3-5. power interface; 4. rectangular heater; 4-1. connection port; 4-2. heat-resistant layer; 4-3. resistance wire; 5. confining pressure device; 5-1. base; 5-2. loading pressure head; 5-3. baffle. DETAILED DESCRIPTION

[0035] Combine the following Figures 1 to 6 , the specific embodiments of the present invention are described in detail. In the description of the present invention, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0036] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features; in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0037] It should be noted that the circuit connections involved in the present invention all adopt conventional circuit connection methods and do not involve any innovation.

[0038] Example

[0039] like Figure 1 and Figure 6 As shown, a test system for simulating hot dry rock proppant fracturing includes: a rock specimen 2, an injection system 1, a confining pressure device 5 and an acoustic emission monitoring system. Figure 2 As shown, the rock specimen 2 is a cubic structure with primary fractures. A wellbore is opened on one of the surfaces of the rock specimen 2 toward the inside of the rock specimen 2, and this surface is called the front surface. A casing 2-1 is inserted into the wellbore, and one end of the casing 2-1 extends from the wellbore to the outside of the rock specimen 2; Figure 1 As shown, the injection system 1 includes a booster pump 1-1, which is fixed on the operating table through a booster pump base 1-6. The input end of the booster pump 1-1 is connected to multiple liquid storage tanks 1-2 through multiple pipes 1-5, each pipe is equipped with a pipe valve 1-4, each liquid storage tank 1-2 stores different types of proppant fracturing fluids, and each liquid storage tank 1-2 is equipped with a liquid storage tank water injection port 1-3. The output end 1-7 of the booster pump 1-1 is connected to the casing 2-1 on the rock specimen 2, which is used to provide different proppant fracturing fluids to the inside of the rock specimen 2 at different stages; the booster pump 1-1 is a booster self-priming pump, which can draw the liquid in the liquid storage tank 1-2 into the pump, and the booster pump 1-1 has a flow controller to control the injection rate and pressure of the liquid; as shown Figure 5 and Figure 3 As shown, the confining pressure device 5 is used to apply pressure loading to the rock specimen 2 to create a confining pressure environment. A base 5-1 is provided inside the confining pressure device 5 for setting a clamping steel frame 3. Three baffles 5-3 are provided on the base 5-1. The three baffles 5-3 are respectively two symmetrically arranged vertical plates and a horizontal plate connected between the tops of the two vertical plates. Each baffle 5-3 is provided with a loading pressure head 5-2. The clamping steel frame 3 is used to clamp and fix the rock specimen 2, and a heating system is provided on the clamping steel frame 3 for temperature control of the rock specimen 2; the acoustic emission monitoring system is used to process and analyze signals of crack generation and expansion of the rock specimen 2 during the test, including: an acoustic emission monitor and multiple acoustic emission probes, the multiple acoustic emission probes are connected to the acoustic emission detector, and the acoustic emission probes are set in the original cracks of the rock specimen 2 to measure the new cracks and distribution of the rock specimen 2 during the fracturing process.

[0040] In some embodiments, the borehole diameter on the rock specimen 2 is 10 mm and the depth is 75 mm. The casing 2-1 in the borehole is a metal casing, and the casing 2-1 and the borehole are fixed with epoxy resin glue to ensure that the casing 2-1 can extend into the interior of the rock specimen 2 and to ensure the sealing between the casing 2-1 and the wellbore. The casing 2-1 extends out of the surface of the rock specimen 2 for a section of 10 mm in length and is used to connect to the output end 1-7 of the booster pump 1-1.

[0041] like Figure 3As shown, the clamping steel frame 3 is a rectangular steel frame, including a steel frame body 3-1 and a plurality of electric push rods 3-2. The plurality of electric push rods 3-2 are correspondingly arranged at each vertex of the steel frame body 3-1, and the telescopic ends of the electric push rods 3-2 are all facing the center point of the rectangular steel frame. By controlling the length of each electric push rod 3-2, it is suitable for clamping rock specimens 2 of different sizes. An arrangement hole 3-4 is provided on the steel frame body 3-1. The acoustic emission probe is placed between the original cracks of the rock, and the other end is connected to the acoustic emission monitor through the arrangement hole 3-4. The acoustic emission monitor is placed behind the confining pressure device 5 for monitoring the test process. The electric push rod 3-2 is powered by an external power supply, and the power interface 3-5 of the power supply is arranged on the steel frame body 3-1.

[0042] In some embodiments, in order to improve the clamping stability of the electric push rod 3 - 2 on the rock sample 2, a push rod support block 3 - 3 is provided on the end of the telescopic end of each electric push rod 3 - 2.

[0043] like Figure 4 As shown, the heating system includes: two heaters 4 and a temperature sensor. The two heaters 4 are rectangular heaters, which are sequentially mounted on the cubic rock specimen 2, and the rectangular heaters are equidistantly arranged to ensure uniform heating of the rock specimen 2; the temperature sensor is used to detect the temperature of the rock specimen 2 in real time; the temperature sensor is arranged on a surface of the rock specimen 2 away from the wellbore surface.

[0044] Specifically, the rectangular heater includes a rectangular shell, a resistance wire 4-3 and a heat-resistant layer 4-2 are arranged inside the rectangular shell, and a detachable connection port 4-1 is provided at the midpoint of one side of the rectangular shell to facilitate the installation of the heater 4.

[0045] like Figure 1 As shown, the injection system 1 has three liquid storage tanks 1-2, which store distilled water, sand-carrying liquid and displacement liquid respectively.

[0046] A method for conducting an experiment using a test system simulating hot dry rock proppant fracturing in this embodiment includes the following steps:

[0047] S1. Prepare a rock specimen 2, process the rock specimen 2 into a cubic structure, open a wellbore on the front of the rock specimen 2, and insert a casing 2-1 into the wellbore; the processing process of the rock specimen 2 is specifically as follows: symmetrically cut the rock specimen 2 with a rock cutter to obtain a regular 150mm×150mm×150mm cubic block, and grind the cut surface of the rock specimen 2 with a rock grinder.

[0048] S2 After that, the clamping steel frame 3 is placed on the base of the confining pressure device 5, the electric push rod 3-2 on the intelligent steel frame is adjusted according to the size of the specimen, the rock specimen 2 is clamped and fixed between the push rod support blocks 3-3 of multiple electric push rods 3-2, the heating system is connected to the rock specimen 2, and the acoustic emission probe is installed in the original cracks of the rock specimen 2; in S2, when the heating system is connected and fixed, the two heaters 4 are respectively fixed at a distance of approximately one-third of the length of the rock specimen 2 from the left and right end faces of the rock specimen 2, and the connecting port 4-1 is closed to connect the heater 4 and the temperature sensor.

[0049] S3. Heat the rock specimen 2 through the heating system according to the temperature required by the test, and keep it warm after reaching the target temperature; set the heating temperature to 150°C, and keep it warm for 2 hours after reaching the target temperature to ensure that the rock specimen 2 is heated evenly.

[0050] S4. Control different loading heads 5-2 of the confining pressure device 5 to load the rock specimen 2 according to the load size required by the test; the confining pressure device 5 is connected to a confining pressure controller, and the confining pressure value applied by the loading heads 5-2 at the left and right ends is 2Mpa, and the confining pressure value applied by the upper head is 5Mpa through the confining pressure controller; thereby simulating the ground stress state of the deep rock mass.

[0051] S5. Connect the output end 1-7 of the booster pump 1-1 of the injection system 1 to the casing 2-1 of the rock specimen 2, set the injection rate of the booster pump 1-1 according to the test requirements, and inject different proppant fracturing fluids into the rock specimen 2 at different stages.

[0052] S6. The data of the entire test process are collected and recorded by the acoustic emission monitor. After the test is completed, the heater 4 and the confining pressure device 5 are turned off and released. When the temperature drops to room temperature, the rock specimen 2 is taken out and placed in a CT scanner to observe and analyze the crack characteristics.

[0053] The proppant fracturing fluid in each stage has the same function as the fracturing fluid in the construction process; the injection of proppant fracturing fluid in different stages includes:

[0054] The pipe valve 1-4 of the pipe 1-5 connecting the liquid storage box 1-2 containing distilled water and the booster pump 1-1 is opened, and the distilled water is injected into the rock specimen 2 to create cracks.

[0055] After the data is stable, close the pipe valve 1-4 of the liquid storage tank 1-2 containing distilled water, and then open the pipe valve 1-4 on the pipeline 1-5 connected to the liquid storage tank 1-2 containing sand-carrying liquid, control the injection rate of the booster pump 1-1 according to the test requirements, and inject the sand-carrying liquid into the rock specimen 2.

[0056] After the data is stable, close the pipe valve 1-4 on the pipeline 1-5 connected to the storage tank 1-2 containing the sand-carrying fluid, and then open the pipe valve 1-4 on the pipeline 1-5 connected to the storage tank 1-2 containing the displacement fluid, control the injection rate of the booster pump 1-1 according to the test requirements, inject the displacement fluid, and bring the proppant in the sand-carrying fluid into the cracks of the rock specimen 2.

[0057] To ensure the safety of the experiment or to compare the injection rate and injection pressure values, the injection pressure was set to 50 MPa and the injection rate was 5 ml / min when injecting distilled water; the injection pressure was set to 10 MPa and the injection rate was 1 ml / min when injecting sand-carrying fluid; the injection pressure was set to 20 MPa and the injection rate was 5 ml / min when injecting displacement fluid.

[0058] The above disclosures are only several preferred specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A test system for simulating hot dry rock proppant fracturing, characterized in that: Used for carrying out a proppant fracturing experiment on a rock specimen (2), the rock specimen (2) being a cubic structure with primary fractures, one surface of which is provided with a wellbore, a casing (2-1) being inserted in the wellbore, one end of the casing (2-1) extending from the wellbore to the outside of the rock specimen (2), the test system comprising: An injection system (1) comprises a booster pump (1-1), wherein an input end of the booster pump (1-1) is respectively connected to a plurality of liquid storage tanks (1-2) via a plurality of pipelines (1-5), each liquid storage tank (1-2) storing a different type of proppant fracturing fluid, and an output end (1-7) of the booster pump (1-1) is connected to a casing (2-1) on the rock specimen (2) for providing different proppant fracturing fluids to the inside of the rock specimen (2) at different stages; A confining pressure device (5) is used to apply pressure to the rock specimen (2) to create a confining pressure environment. A clamping steel frame (3) is provided inside the confining pressure device (5). The clamping steel frame (3) is used to clamp and fix the rock specimen (2). A heating system is provided on the clamping steel frame (3) to control the temperature of the rock specimen (2). An acoustic emission monitoring system is used to process and analyze signals of crack generation and expansion of a rock specimen (2) during fracturing, and comprises an acoustic emission monitor and a plurality of acoustic emission probes, wherein the plurality of acoustic emission probes are connected to an acoustic emission detector, and the acoustic emission probes are arranged in primary cracks of the rock specimen (2) to measure the appearance and distribution of newly generated cracks in the rock specimen (2) during fracturing.

2. The test system for simulating hot dry rock proppant fracturing according to claim 1, characterized in that: The casing (2-1) is a metal casing, one end of which extends out from the wellbore, and the casing (2-1) and the wellbore are fixed using epoxy resin glue.

3. The test system for simulating hot dry rock proppant fracturing according to claim 1, characterized in that: The clamping steel frame (3) is a rectangular steel frame, comprising a steel frame body (3-1) and a plurality of electric push rods (3-2), wherein the plurality of electric push rods (3-2) are correspondingly arranged at each vertex of the steel frame body (3-1), and the telescopic ends of the electric push rods (3-2) are all oriented toward the center point of the rectangular steel frame.

4. The test system for simulating hot dry rock proppant fracturing according to claim 3, characterized in that: A push rod support block (3-3) is provided on the end of the telescopic end of each electric push rod (3-2).

5. The test system for simulating hot dry rock proppant fracturing according to claim 3, characterized in that: The heating system comprises: Two heaters (4), both of which are rectangular heaters, are sequentially mounted on the rock specimen (2) with a cubic structure; A temperature sensor is connected to the heater (4), and is used to detect the temperature of the rock specimen (2) in real time; the temperature sensor is arranged on a surface of the rock specimen (2) away from a surface where a wellbore is arranged.

6. The test system for simulating hot dry rock proppant fracturing according to claim 5, characterized in that: The rectangular heater comprises: A rectangular shell, wherein a resistance wire (4-3) and a heat-resistant layer (4-2) are arranged inside the rectangular shell, and a detachable connection port (4-1) is provided at the midpoint of one side of the rectangular shell.

7. The test system for simulating hot dry rock proppant fracturing according to claim 1, characterized in that: The injection system (1) has three liquid storage boxes (1-2) for storing distilled water, sand-carrying liquid and displacement liquid respectively.

8. The method for conducting an experiment on a test system for simulating hot dry rock proppant fracturing according to claim 1, characterized in that: The following steps are involved: S1, preparing a rock sample (2), processing the rock sample (2) into a cubic structure, opening a wellbore on the front side of the rock sample (2), and inserting a casing (2-1) into the wellbore; S2 places the clamping steel frame (3) on the base of the confining pressure device (5), fixes the rock specimen (2) on the clamping steel frame (3), connects the heating system to the rock specimen (2), and installs an acoustic emission probe in the original crack of the rock specimen (2); S3, heating the rock specimen (2) through a heating system according to the temperature required for the test, and keeping the temperature constant after reaching the target temperature; S4, controlling the confining pressure device (5) to load the rock specimen (2) with different loading heads (5-2) according to the load size required for the test; S5, connecting the output end (1-7) of the booster pump (1-1) of the injection system (1) to the casing (2-1) of the rock specimen (2), setting the injection rate of the booster pump (1-1) according to the test requirements, and injecting different proppant fracturing fluids into the rock specimen (2) at different stages; S6. The data of the entire test process is collected and recorded by the acoustic emission monitor. After the test is completed, the rock specimen (2) is taken out and placed in a CT scanner to observe and analyze the crack characteristics.

9. The method for conducting an experiment on a test system for simulating hot dry rock proppant fracturing according to claim 8, characterized in that: The injection steps of proppant fracturing fluid at different stages include: The pipe valve (1-4) of the pipe (1-5) connecting the liquid storage box (1-2) containing distilled water and the booster pump (1-1) is opened, and the distilled water is injected into the rock specimen (2) to cause cracks; After the data is stabilized, the pipe valve (1-4) of the liquid storage box (1-2) containing distilled water is closed, and then the pipe valve (1-4) on the pipeline (1-5) connected to the liquid storage box (1-2) containing sand-carrying liquid is opened, and the injection rate of the booster pump (1-1) is controlled according to the test requirements to inject the sand-carrying liquid into the rock specimen (2); After the data is stabilized, the pipe valve (1-4) on the pipe (1-5) connected to the storage tank (1-2) containing the sand-carrying fluid is closed, and then the pipe valve (1-4) on the pipe (1-5) connected to the storage tank (1-2) containing the displacement fluid is opened, and the injection rate of the booster pump (1-1) is controlled according to the test requirements to inject the displacement fluid and bring the proppant in the sand-carrying fluid into the cracks of the rock specimen (2).

10. The test system for simulating hot dry rock proppant fracturing according to claim 8, characterized in that: When injecting distilled water, set the injection pressure to 50Mpa and the injection rate to 5ml / min; when injecting sand-carrying liquid, set the injection pressure to 10Mpa and the injection rate to 1ml / min; When injecting displacement fluid, the injection fracturing pressure is set to 20 MPa and the injection rate is set to 5 ml / min.

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