Fine measurement device for rock fracture process in high-temperature environment

Abstract

The invention relates to the technical field of rock mechanics experiments, in particular to a fine measurement device for a rock fracture process in a high-temperature environment, and the device comprises a material selection module which is used for cutting same prefabricated cracks on a plurality of prefabricated rocks to obtain a plurality of experimental rocks, and selecting two target rocks; the experimental device is used for respectively obtaining a first acoustic emission signal and a second acoustic emission signal; the denoising module is used for denoising the second acoustic emission signal according to the first acoustic emission signal to obtain a rock fracture process acoustic emission signal; the analysis module is used for analyzing and describing rock fracture behaviors according to the acoustic emission signals in the rock fracture process; by simulating the high-temperature and high-pressure environment, acoustic emission signals in the three-point bending fracture experiment process in the high-temperature environment can be monitored, the fracture behavior of the rock under the high-temperature condition can be carefully captured and described, and the accuracy and practicability of the fine measurement device for the rock fracture process in the high-temperature environment are further improved.

Description

Technical Field

[0001] The invention relates to the technical field of rock mechanics experiments, and in particular to a device for precisely measuring rock fracture processes in a high-temperature environment. Background Art

[0002] With the increase of energy demand in my country, the development of deep earth resources with rich reserves has gradually become an important area to improve my country's oil and gas supply capacity. Hydraulic fracturing technology is a key technology for increasing production in deep reservoir development. Compared with shallow reservoir rocks, the increase in temperature in deep reservoirs makes the deformation and destruction of rocks have plasticity-enhanced mechanical properties, which leads to changes in the expansion of hydraulic fractures and the communication behavior with natural fractures, significantly affecting the fracturing effect. Rock fracture is caused by the expansion and evolution of tiny cracks inside the rock. At present, in indoor experimental research, the acquisition of rock fracture information has become increasingly important. In the past, fracture experiments could only measure less macroscopic data, which was difficult to be precise. Acoustic emission can capture the tiny signals in the process of microcrack development and eventually generating macroscopic fractures, but the acoustic emission probe cannot be directly attached to the surface of high-temperature rocks, and the instrument is easily damaged. Therefore, it is necessary to achieve precise measurement of rock fracture process in high-temperature environment. The research results obtained can provide parameter support for deep reservoir fracturing under high-temperature conditions.

[0003] Chinese patent application publication number: CN113885073A discloses a method for fine-grained analysis of rock fracture and fracturing acoustic emission based on original waveforms, including conducting a three-point bending fracture test on the test material under acoustic emission monitoring, analyzing the complete waveform characteristics of the elastic wave released during the fracture process of the material; calculating the waveform synchronization and waveform onset time, constructing the weight function of the nonlinear equation group and solving it through an unconstrained optimization algorithm; determining the spatial distribution characteristics of the acoustic emission event waveform parameters and wave velocity, and comprehensively characterizing the nonlinear fracture characteristics of the fracturing cracks through characteristic parameters directly related to the nonlinear fracture of the rock: acoustic emission energy, acoustic emission event wave velocity, acoustic emission frequency and source mechanism; significantly improving the positioning accuracy of the fracturing, and then determining the spatial distribution of waveform parameters related to the nonlinear fracture, and finally finely monitoring the nonlinear fracture characteristics of the expansion of the fracturing cracks through acoustic emission, to ensure the safe and efficient exploitation of geological energy such as oil, gas, geothermal energy, and coal.

[0004] Chinese patent application publication number: CN116796571A discloses a rock tectonic stress prediction system based on acoustic emission characteristics. The invention discloses a rock tectonic stress prediction system based on acoustic emission characteristics. The rock tectonic stress prediction system includes: an acoustic emission detection module, a data processing module, a data conversion module, and a data analysis module. The acoustic emission detection module is used to detect and record the acoustic emission phenomenon accompanied by deformation or fracture when the rock is loaded in real time. The data processing module collects the data monitored by the acoustic emission detection module and transmits the collected data to the computer terminal. The data conversion module is used to convert the collected analog signal. The rock tectonic stress prediction system based on acoustic emission characteristics detects the structure and stress of the rock through acoustic emission, compares and analyzes the basic characteristic parameters of the acoustic emission with the data of the destruction of the rock specimen, and uses algorithm calculation to accurately and effectively analyze the destruction of the rock, and timely and effectively warns and predicts the dangers such as rock burst.

[0005] However, the above method has the following problems: analyzing the cracking characteristics of rocks through acoustic emission characteristics cannot effectively eliminate the interference of noise, and at the same time, it is impossible to observe the communication relationship between the cracks formed in the cracking process of rocks under high temperature and high pressure and the natural cracks. Summary of the invention

[0006] To this end, the present invention provides a precise measurement device for the rock fracture process under a high temperature environment, so as to overcome the problem that the prior art analyzes the cracking characteristics of rocks through acoustic emission characteristics, cannot effectively eliminate the interference of noise, and cannot observe the communication relationship between the cracks formed in the rock cracking process under high temperature and high pressure and the natural cracks.

[0007] To achieve the above object, the present invention provides a device for finely measuring rock fracture process in a high temperature environment, comprising: A material selection module, which is used to cut the same prefabricated cracks on a plurality of prefabricated rocks to obtain a plurality of experimental rocks, and to select a first target rock and a second target rock from the plurality of experimental rocks; An experimental device connected to the material selection module, used to assign the first target rock to a first experimental stage to obtain a first acoustic emission signal, and to assign the second target rock to a second experimental stage to obtain a second acoustic emission signal; A denoising module, connected to the experimental device, for denoising the second acoustic emission signal according to the first acoustic emission signal to obtain an acoustic emission signal of a rock fracture process; An analysis module, connected to the denoising module, for analyzing and describing rock fracture behavior according to the acoustic emission signal of the rock fracture process; Among them, the prefabricated rock is a rock with the same material, size and shape; the first target rock and the second target rock are two experimental rocks whose weight difference is within a preset weight difference; the first experimental stage is a high temperature stage; the second experimental stage is a high temperature and high pressure stage; the denoising process is to obtain a preprocessed signal by statistically analyzing the characteristics and spectrum information of the first acoustic emission signal, and filtering and eliminating the noise in the second acoustic emission signal according to the preprocessed signal.

[0008] Furthermore, the experimental device comprises: A heating cabinet, used to heat the first target rock and the second target rock and observe the cracking process of the first target rock and the second target rock; A guide device, which is arranged in the heating cabinet, and is used to support the first target rock and the second target rock, and to move the positions of the first target rock and the second target rock in a horizontal direction; A clamp, connected to the guide rail, for fastening the first target rock and the second target rock and moving the first target rock and the second target rock in a vertical direction; A pressurizer, which is arranged in the heating cabinet and is used to press the first target rock and the second target rock and measure the pressure value; A cooling pipe, which is arranged on the heating cabinet and is used to cool the heating cabinet after the heating is completed; A signal transmitter is arranged on the heating cabinet and is used to collect the first acoustic emission signal and the second acoustic emission signal.

[0009] Furthermore, the material selection module cuts the same prefabricated cracks on a number of the prefabricated rocks to obtain a number of the experimental rocks, weighs the experimental rocks in turn to obtain the weight of each experimental rock and selects two experimental rocks with the closest weights, and calculates the weight difference between the two experimental rocks.

[0010] Furthermore, the material selection module determines the two experimental rocks according to the comparison result between the weight difference and the preset weight difference, wherein: If the weight difference is less than the preset weight difference, determining that the two test rocks are the first target rock and the second target rock; If the weight difference is not less than the preset weight difference, re-preparing a plurality of the test rocks and selecting two of the test rocks to compare the weight difference with the preset weight difference until the first target rock and the second target rock are selected; Wherein, the preset weight difference is positively correlated with the density of the prefabricated rock.

[0011] Further, placing the first target rock in the fixture, and recording the first acoustic emission signal emitted by the first target rock during the heating process; The second target rock is placed in the fixture, the second target rock is pressurized using the pressurizer, and the second acoustic emission signal emitted by the second target rock during the heating process is recorded.

[0012] Further, the signal transmitter collects and transmits the first acoustic emission signal and the second acoustic emission signal to the denoising module respectively; The denoising module analyzes the sound features and spectrum information in the first acoustic emission signal, and processes the second acoustic emission signal according to the sound features and the spectrum information.

[0013] Furthermore, the denoising module processes the first acoustic emission signal according to the sound characteristics using a maximum a posteriori probability algorithm and a minimum mean square error algorithm to obtain the preprocessed signal, and extracts the frequency range of the first target rock cracking sound in the preprocessed signal according to the spectrum information.

[0014] Furthermore, the denoising module filters each original sound wave frequency in the second acoustic emission signal according to the frequency range of the first target rock cracking sound, wherein: If the original sound wave frequency is less than the first frequency value or greater than the second frequency value, removing the original sound wave corresponding to the original sound wave frequency from the second acoustic emission signal; If the original sound wave frequency is not less than the first frequency value and not greater than the second frequency value, retaining the original sound wave corresponding to the original sound wave frequency in the second acoustic emission signal; Among them, the first frequency value and the second frequency value are respectively the minimum and maximum boundary values ​​of the frequency range of the first target rock cracking sound; the first frequency value is less than the second frequency value; and the original sound wave is the sound wave emitted by different sound sources contained in the second acoustic emission signal.

[0015] Furthermore, the denoising module compares the sound features of the preprocessed signal with the sound features of the original sound wave retained in the second acoustic emission signal, and selects the sound waves with consistent sound features to obtain the rock fracture process acoustic emission signal.

[0016] Furthermore, when the pressure value measured by the pressurizer is less than a preset pressure value, the signal transmitter stops collecting the second acoustic emission signal; Wherein, the preset pressure value is positively correlated with the density of the prefabricated rock.

[0017] Compared with the prior art, the beneficial effect of the present invention lies in that the present invention utilizes a material selection module to cut the same cracks on prefabricated rocks to obtain experimental rocks, and prefabricates natural cracks on the rocks, thereby effectively simulating the communication relationship between the cracks formed in the cracking process of rocks under high temperature and high pressure and the natural cracks, and effectively improving the accuracy of the fine measurement device of the rock fracture process under high temperature environment.

[0018] Furthermore, the present invention utilizes an experimental device to simulate a high temperature and high pressure environment, and is able to monitor the acoustic emission signals during a three-point bend fracture experiment under a high temperature environment, thereby achieving precise capture and characterization of the fracture behavior of rocks under high temperature conditions. The research results can provide accurate parameters for hydraulic fracturing under high temperature conditions, further improving the accuracy of the precise measurement device for the rock fracture process under a high temperature environment.

[0019] Furthermore, the present invention collects and processes and compares the acoustic emission signals of rock cracking at high temperature under normal pressure and the acoustic emission signals of rock cracking under high temperature and high pressure, thereby effectively removing noise in the acoustic emission signals and further improving the accuracy of the fine measurement device of the rock fracture process under high temperature environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the structure of the experimental device of the device for finely measuring rock fracture process under high temperature environment of the present invention; Figure 2 It is a schematic diagram of the structure of the internal device of the heating cabinet of the experimental device of the present invention; Figure 3 A schematic diagram of prefabricated cracks according to an embodiment of the present invention; Figure 4 This is a schematic diagram of determining target rock in an embodiment of the present invention; Among them, 1, heating cabinet; 2, pressure head; 3, waveguide rod; 4, signal acquisition probe; 5, signal transmission line; 6, guide rail; 7, signal receiving device; 8, loading hydraulic cylinder; 9, connecting pin; 10, pressure head locking nut; 11, pressure roller fixing plate; 12, pressure roller; 13, target rock; 14, cooling pipe; 15, waveguide rod fixing plate; 16, sealing ring; 17, waveguide rod screw; 18, fixing bolt; 19, fastening screw; 20, clamp support; 21, guide rail support, 22, prefabricated crack. DETAILED DESCRIPTION

[0021] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0023] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0024] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] See also Figure 1 As shown, it is a schematic diagram of the structure of an experimental device of a fine measurement device for rock fracture process in a high temperature environment of the present invention, a fine measurement device for rock fracture process in a high temperature environment, comprising: A material selection module, which is used to cut the same prefabricated cracks on a plurality of prefabricated rocks to obtain a plurality of experimental rocks, and to select a first target rock and a second target rock from the plurality of experimental rocks; An experimental device, which is connected to the material selection module, is used to assign the first target rock to the first experimental stage to obtain a first acoustic emission signal, and to assign the second target rock to the second experimental stage to obtain a second acoustic emission signal; A denoising module, which is connected to the experimental device and is used to denoise the second acoustic emission signal according to the first acoustic emission signal to obtain an acoustic emission signal of the rock fracture process; An analysis module, which is connected to the denoising module, is used to analyze and describe the rock fracture behavior according to the acoustic emission signal of the rock fracture process; Among them, the prefabricated rock is a rock with the same material, size and shape; the first target rock and the second target rock are two experimental rocks with a weight difference within a preset weight difference; the first experimental stage is a high temperature stage; the second experimental stage is a high temperature and high pressure stage; the denoising process is to statistically analyze the characteristics and spectrum information of the first acoustic emission signal to obtain a preprocessed signal, and filter and eliminate the noise in the second acoustic emission signal according to the preprocessed signal.

[0026] See also Figure 2 As shown, it is a schematic diagram of the structure of the internal device of the heating cabinet of the experimental device of the present invention, and the experimental device includes: A heating cabinet for heating the first target rock and the second target rock and observing the cracking process of the first target rock and the second target rock; A guide device is arranged in the heating cabinet to support the first target rock and the second target rock and to move the positions of the first target rock and the second target rock in a horizontal direction; A clamping device connected to the guide device, used to fasten the first target rock and the second target rock, and to move the first target rock and the second target rock in a vertical direction; A pressurizer, which is arranged in the heating cabinet and is used to press the first target rock and the second target rock and measure the pressure value; A cooling pipe is provided on the heating cabinet to cool the heating cabinet after heating is completed; The signal transmitter is arranged on the heating cabinet and is used for collecting the first acoustic emission signal and the second acoustic emission signal.

[0027] Example 1: In this example, please cooperate with Figure 1 See also Figure 2 As shown, the guide rail device of the present invention includes a guide rail 6 and a guide rail support 21; the clamp device includes a waveguide rod 3, a pressure roller fixing plate 11, a pressure roller 12, a waveguide rod fixing plate 15, a sealing ring 16, a waveguide rod screw 17, a fixing bolt 18, a fastening screw 19 and a clamp support 20; the pressurizer includes a pressure head 2, a loading hydraulic cylinder 8, a connecting pin 9 and a pressure head locking nut 10; the signal transmitter includes a signal acquisition probe 4, a signal transmission line 5 and a signal receiving device 7.

[0028] Among them, the pressure roller 12 is connected to the pressure head 2 through the pressure roller fixing plate 11; the waveguide rod screw 17 is connected to the waveguide rod 3; the waveguide rod screw 17 penetrates and connects the front and rear waveguide rod fixing plates 15; the loading hydraulic cylinder 8 is arranged in the heating cabinet 1; the pressure head 2 is connected to the loading hydraulic cylinder 8 through the connecting pin 9; the guide rail support 21 is arranged in the heating cabinet 1; the guide rail 6 is arranged on the guide rail support 21; the clamp support 20 is connected to the guide rail 6 through a T-slot and is fixed to the guide rail 6 by a fastening screw 19; One side of the heating cabinet 1 is a cabinet door, and a waveguide rod through hole is opened on the cabinet door and the other side opposite to the cabinet door, and a visualization window is set, the visualization window is completely sealed, the waveguide rod 3 passes through the waveguide rod through hole and is sealed by a sealing ring 16; the cooling tube 14 is wrapped around the waveguide rod 3; the waveguide rod 3 is equipped with a signal acquisition probe 4 at one end outside the heating cabinet 1; the signal acquisition probe 4 is connected to the signal receiving device 7 through a signal transmission line 5; the pressure head locking nut 10 is connected to the pressure head 2; the fixing bolt 18 is connected to the guide rail 6.

[0029] Specifically, the material selection module cuts the same prefabricated cracks on several prefabricated rocks to obtain several experimental rocks, weighs the experimental rocks in turn to obtain the weight of each experimental rock, selects two experimental rocks with the closest weight, and calculates the weight difference between the two experimental rocks.

[0030] Example 2: Please refer to Figure 3 As shown, it is a schematic diagram of the prefabricated cracks in an embodiment of the present invention. Based on Example 1, this embodiment is different from it in that the same prefabricated cracks 22 are cut on the prefabricated rock to obtain a number of experimental rocks, the experimental rocks are weighed in turn to obtain the weight of each experimental rock, and the two experimental rocks with the closest weight are selected, and the weights of the two experimental rocks are calculated to obtain the weight difference.

[0031] Specifically, the present invention utilizes a material selection module to cut identical cracks on prefabricated rocks to obtain experimental rocks, and prefabricates natural cracks on the rocks, thereby effectively simulating the communication relationship between cracks formed during the cracking process of rocks under high temperature and high pressure and natural cracks, and effectively improving the accuracy of the fine measurement device of the rock fracture process under high temperature environment.

[0032] See also Figure 4 As shown, it is a schematic diagram of determining the target rock in an embodiment of the present invention. The material selection module determines the two experimental rocks according to the comparison result between the weight difference and the preset weight difference, wherein: If the weight difference is less than the preset weight difference, the two experimental rocks are determined to be the first target rock and the second target rock; If the weight difference is not less than the preset weight difference, a number of experimental rocks are prepared again and two experimental rocks are selected to compare the weight difference with the preset weight difference until the first target rock and the second target rock are selected; Embodiment 3: Based on Embodiment 2, this embodiment is different from it in that the preset weight difference is 10 grams. If the weight difference of the two experimental rocks is 5 grams, which is less than the preset weight difference of 10 grams, then the two experimental rocks are determined to be target rocks; If the weight difference of the two experimental rocks is 15 grams, which is greater than the preset weight difference of 10 grams, several experimental rocks are re-prepared and two experimental rocks are selected to compare the weight difference with the preset weight difference until the target rock is selected.

[0033] Among them, the preset weight difference is positively correlated with the density of the prefabricated rock.

[0034] It is understandable that the greater the density of the prefabricated rock, the greater the weight at the same volume, and the greater the preset weight difference.

[0035] Optionally, the density of the prefabricated rock is 1500 kg per cubic meter, and the preset weight difference is 5 grams; The density of the prefabricated rock is 2000 kg per cubic meter, and the preset weight difference is 7.5 grams; The density of the prefabricated rock is 2500 kg per cubic meter, and the preset weight difference is 10 grams.

[0036] Specifically, a first target rock is placed in a fixture, and a first acoustic emission signal emitted by the first target rock during a heating process is recorded; The second target rock is placed in the fixture, the second target rock is pressurized by using a pressurizer, and a second acoustic emission signal emitted by the second target rock during the heating process is recorded.

[0037] Specifically, the present invention utilizes an experimental device to simulate a high temperature and high pressure environment, and is able to monitor the acoustic emission signals during a three-point bend fracture experiment under a high temperature environment, thereby achieving precise capture and characterization of the fracture behavior of rocks under high temperature conditions. The research results can provide accurate parameters for hydraulic fracturing under high temperature conditions, further improving the accuracy of the precise measurement device for the rock fracture process under a high temperature environment.

[0038] Specifically, the signal transmitter collects and transmits the first acoustic emission signal and the second acoustic emission signal to the denoising module respectively; The denoising module analyzes the sound features and spectrum information in the first acoustic emission signal, and processes the second acoustic emission signal according to the sound features and spectrum information.

[0039] Specifically, the denoising module processes the first acoustic emission signal using the maximum a posteriori probability algorithm and the minimum mean square error algorithm according to the sound characteristics to obtain a preprocessed signal, and extracts the frequency range of the first target rock cracking sound in the preprocessed signal according to the spectrum information.

[0040] It is understandable that for those skilled in the art, the maximum a posteriori probability algorithm is a method of estimating parameters by combining prior knowledge and observation data using Bayes' theorem; the minimum mean square error algorithm is a method of minimizing the mean square error between the actual output and the expected output. Both are obvious methods and will not be described in detail here.

[0041] Specifically, the denoising module filters the original sound wave frequencies in the second acoustic emission signal according to the frequency range of the first target rock cracking sound, wherein: If the original sound wave frequency is less than the first frequency value or greater than the second frequency value, removing the original sound wave corresponding to the original sound wave frequency from the second acoustic emission signal; If the original sound wave frequency is not less than the first frequency value and not greater than the second frequency value, retaining the original sound wave corresponding to the original sound wave frequency in the second acoustic emission signal; Embodiment 4: Based on Embodiment 3, this embodiment is different from it in that the frequency range of the target rock cracking sound is 3 Hz to 20 Hz, the first frequency value is 3 Hz, and the second frequency value is 20 Hz. If the original sound wave frequency is 2 Hz, which is less than the first frequency value of 3 Hz, the original sound wave corresponding to the original sound wave frequency of 2 Hz is removed from the second acoustic emission signal; If the original sound wave frequency of 30 Hz is greater than the second frequency value of 20 Hz, then the original sound wave corresponding to the original sound wave frequency of 30 Hz is removed from the second acoustic emission signal; If the original sound wave frequency is 15 Hz, which is greater than the first frequency value of 3 Hz and less than the second frequency value of 20 Hz, then the original sound wave corresponding to the original sound wave frequency of 15 Hz is retained in the second acoustic emission signal; Among them, the first frequency value and the second frequency value are respectively the minimum and maximum boundary values ​​of the frequency range of the first target rock cracking sound; the first frequency value is less than the second frequency value; and the original sound wave is the sound wave emitted by different sound sources contained in the second acoustic emission signal.

[0042] Specifically, the denoising module compares the sound features of the preprocessed signal with the sound features of the original sound wave retained in the second acoustic emission signal, and screens the sound waves with consistent sound features to obtain the acoustic emission signal of the rock fracture process.

[0043] Specifically, the present invention collects and processes and compares the acoustic emission signals of rock cracking at high temperature under normal pressure and the acoustic emission signals of rock cracking under high temperature and high pressure, thereby effectively removing noise in the acoustic emission signals and further improving the accuracy of the fine measurement device of the rock fracture process under high temperature environment.

[0044] Specifically, when the pressure value measured by the pressurizer is less than the preset pressure value, the signal transmitter stops collecting the second acoustic emission signal; Embodiment 5: Based on Embodiment 4, this embodiment is different from it in that the preset pressure value is 1000 Newtons, the pressure value measured by the pressurizer is 900 Newtons, which is less than 1000 Newtons, and the signal acquisition probe 4 stops collecting the second acoustic emission signal.

[0045] Among them, the preset pressure value is positively correlated with the density of the prefabricated rock.

[0046] It can be understood that the greater the density of the prefabricated rock, the greater the pressure it can withstand, and the greater the preset pressure value.

[0047] Optionally, the density of the prefabricated rock is 1500 kg per cubic meter and the preset pressure value is 500 Newton; The density of the prefabricated rock is 2000 kg per cubic meter, and the preset pressure value is 1000 Newton; The density of the prefabricated rock is 2500 kg per cubic meter and the preset pressure value is 1500 Newton.

[0048] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A device for finely measuring rock fracture process in a high temperature environment, characterized in that: include: A material selection module, which is used to cut the same prefabricated cracks on a plurality of prefabricated rocks to obtain a plurality of experimental rocks, and to select a first target rock and a second target rock from the plurality of experimental rocks; An experimental device connected to the material selection module, used to assign the first target rock to a first experimental stage to obtain a first acoustic emission signal, and to assign the second target rock to a second experimental stage to obtain a second acoustic emission signal; A denoising module, connected to the experimental device, for denoising the second acoustic emission signal according to the first acoustic emission signal to obtain an acoustic emission signal of a rock fracture process; An analysis module, connected to the denoising module, for analyzing and describing rock fracture behavior according to the acoustic emission signal of the rock fracture process; Among them, the prefabricated rock is a rock with the same material, size and shape; the first target rock and the second target rock are two experimental rocks whose weight difference is within a preset weight difference; the first experimental stage is a high temperature stage; the second experimental stage is a high temperature and high pressure stage; the denoising process is to obtain a preprocessed signal by statistically analyzing the characteristics and spectrum information of the first acoustic emission signal, and filtering and eliminating the noise in the second acoustic emission signal according to the preprocessed signal.

2. The device for finely measuring rock fracture process in a high temperature environment according to claim 1 is characterized in that: The experimental device includes: A heating cabinet, used to heat the first target rock and the second target rock and observe the cracking process of the first target rock and the second target rock; A guide device, which is arranged in the heating cabinet, and is used to support the first target rock and the second target rock, and to move the positions of the first target rock and the second target rock in a horizontal direction; A clamp, connected to the guide rail, for fastening the first target rock and the second target rock and moving the first target rock and the second target rock in a vertical direction; A pressurizer, which is arranged in the heating cabinet and is used to press the first target rock and the second target rock and measure the pressure value; A cooling pipe, which is arranged on the heating cabinet and is used to cool the heating cabinet after the heating is completed; A signal transmitter is arranged on the heating cabinet and is used to collect the first acoustic emission signal and the second acoustic emission signal.

3. The device for finely measuring rock fracture process in a high temperature environment according to claim 2 is characterized in that: The material selection module cuts the same prefabricated cracks on a number of the prefabricated rocks to obtain a number of the experimental rocks, weighs the experimental rocks in turn to obtain the weight of each experimental rock, selects two experimental rocks with the closest weights, and calculates the weight difference between the two experimental rocks.

4. The device for finely measuring rock fracture process in a high temperature environment according to claim 3 is characterized in that: The material selection module determines the two experimental rocks according to the comparison result between the weight difference and the preset weight difference, wherein: If the weight difference is less than the preset weight difference, determining that the two test rocks are the first target rock and the second target rock; If the weight difference is not less than the preset weight difference, re-preparing a plurality of the test rocks and selecting two of the test rocks to compare the weight difference with the preset weight difference until the first target rock and the second target rock are selected; Wherein, the preset weight difference is positively correlated with the density of the prefabricated rock.

5. The device for finely measuring rock fracture process in a high temperature environment according to claim 4 is characterized in that: placing the first target rock in the fixture, and recording the first acoustic emission signal emitted by the first target rock during the heating process; The second target rock is placed in the fixture, the second target rock is pressurized using the pressurizer, and the second acoustic emission signal emitted by the second target rock during the heating process is recorded.

6. The device for finely measuring rock fracture process in a high temperature environment according to claim 5 is characterized in that: The signal transmitter collects and transmits the first acoustic emission signal and the second acoustic emission signal to the denoising module respectively; The denoising module analyzes the sound features and spectrum information in the first acoustic emission signal, and processes the second acoustic emission signal according to the sound features and the spectrum information.

7. The device for finely measuring rock fracture process in a high temperature environment according to claim 6 is characterized in that: The denoising module processes the first acoustic emission signal using a maximum a posteriori probability algorithm and a minimum mean square error algorithm according to the sound characteristics to obtain the preprocessed signal, and extracts the frequency range of the first target rock cracking sound in the preprocessed signal according to the spectrum information.

8. The device for finely measuring rock fracture process in a high temperature environment according to claim 7 is characterized in that: The denoising module filters each original sound wave frequency in the second acoustic emission signal according to the frequency range of the first target rock cracking sound, wherein: If the original sound wave frequency is less than the first frequency value or greater than the second frequency value, removing the original sound wave corresponding to the original sound wave frequency from the second acoustic emission signal; If the original sound wave frequency is not less than the first frequency value and not greater than the second frequency value, retaining the original sound wave corresponding to the original sound wave frequency in the second acoustic emission signal; Among them, the first frequency value and the second frequency value are respectively the minimum and maximum boundary values ​​of the frequency range of the first target rock cracking sound; the first frequency value is less than the second frequency value; and the original sound wave is the sound wave emitted by different sound sources contained in the second acoustic emission signal.

9. The device for finely measuring rock fracture process in a high temperature environment according to claim 8 is characterized in that: The denoising module compares the sound features of the preprocessed signal with the sound features of the original sound waves retained in the second acoustic emission signal, and selects the sound waves with consistent sound features to obtain the rock fracture process acoustic emission signal.

10. The device for finely measuring rock fracture process in a high temperature environment according to claim 9, characterized in that: The pressure value measured by the pressurizer is lower than the preset pressure value, and the signal transmitter stops collecting the second acoustic emission signal; Wherein, the preset pressure value is positively correlated with the density of the prefabricated rock.

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