A dual-channel testing device and method for damage and permeability evolution of rock materials

Abstract

The invention relates to a dual-channel testing device and method for damage and permeability evolution of rock materials, which are used to solve the problem that the testing methods in the prior art are difficult to meet the testing requirements of high precision and a wide range; the device and method comprise: a loading mechanism, a permeability detection mechanism, an acoustic wave detection mechanism and a heating mechanism; the loading mechanism applies pressure to a core sample; the permeability detection mechanism comprises an upstream pipeline, a downstream pipeline, an upstream reference pressure chamber, a downstream reference pressure chamber, an upstream pressure sensor, a downstream pressure sensor and a flow meter; the upstream reference pressure chamber is connected to the upstream pipeline, the downstream reference pressure chamber is connected to the upstream pipeline, the upstream pressure sensor is used to measure the fluid pressure in the upstream pipeline, the downstream pressure sensor is used to measure the fluid pressure in the downstream pipeline, the flow meter is used to measure the flow rate of the fluid in the upstream pipeline, and the heating mechanism is used to control the temperature in the protective cover.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical properties, permeability properties and damage deformation testing of rock materials, and in particular to a dual-channel testing device and method for damage and permeability evolution of rock materials. Background Art

[0002] Rock damage and permeability are key parameters for evaluating the safety of underground salt cavern storage projects. Accurately obtaining the permeability and damage evolution of surrounding rocks during storage operation is of great significance for the analysis of their airtightness and stability. Under the action of cyclic injection and production, the minimum principal stress of the surrounding rock near the salt cavern changes periodically, which will cause continuous shrinkage of the salt cavity volume and progressive damage to the surrounding rock during long-term operation. In previous studies, surrounding rock damage is an important indicator reflecting reservoir stability, but in fact, when the surrounding rock is subjected to high deviatoric stress, its internal damage will be aggravated, and a surge in permeability will occur. In other words, the damage of the surrounding rock not only directly determines the stability of the salt cavern storage, but also indirectly controls its airtightness.

[0003] The essence of damage-induced permeability surge is the result of the development and penetration of cracks inside the rock. For tight rocks that seal oil and gas, the permeability before and after disturbance usually differs by 3 to 5 orders of magnitude. Such a large range of fluctuations poses a great challenge to the accurate measurement of permeability. At present, most of the rock stress-seepage coupling experimental platform test methods are relatively simple. For permeability higher than 10 -17 m 2 For rocks with a permeability lower than 10 -17 m 2 The rock with high permeability is usually tested by the non-steady-state method; and the surrounding rock before and after the disturbance will be in the range of both changes at the same time due to the evolution of permeability. However, the testing methods in the existing technology are difficult to meet the requirements of high precision and wide range of testing. Summary of the invention

[0004] In view of the defects in the prior art, the present invention provides a dual-channel testing device and method for damage and permeability evolution of rock materials, which is used to solve the problem that the testing methods in the prior art are difficult to meet the requirements of high precision and wide range of testing.

[0005] In order to achieve the above-mentioned object, the present invention provides a dual-channel test device for damage and permeability evolution of rock materials, comprising: a loading mechanism, a permeability detection mechanism, an acoustic wave detection mechanism and a heating mechanism;

[0006] The loading mechanism comprises a pressure loading rod, a protective cover, an upper pressure head and a lower pressure head, wherein the lower pressure head is fixedly mounted on a machine base, the upper pressure head and the lower pressure head are arranged opposite to each other, one end of the pressure loading rod is fixedly connected to the upper pressure head, and the other end of the pressure loading rod is connected to a pressure element; a core sample is fixed between the upper pressure head and the lower pressure head, an elastic sealing layer is wrapped on the outer surface of the core sample, a fluid inlet is provided on the lower pressure head, a fluid outlet is provided on the upper pressure head, and a detection fluid enters from the fluid inlet and passes through the core sample and then flows out from the fluid outlet, the upper pressure head and the lower pressure head are both arranged inside the protective cover, and the protective cover is connected to a fluid pump;

[0007] The permeability detection mechanism includes an upstream pipeline, a downstream pipeline, an upstream reference pressure chamber, a downstream reference pressure chamber, an upstream pressure sensor, a downstream pressure sensor and a flow meter;

[0008] The upstream pipeline is in communication with the fluid inlet, the downstream pipeline is in communication with the fluid outlet, the upstream reference pressure chamber is in communication with the upstream pipeline, the downstream reference pressure chamber is in communication with the upstream pipeline, the upstream pressure sensor is used to measure the fluid pressure in the upstream pipeline, the downstream pressure sensor is used to measure the fluid pressure in the downstream pipeline, the flow meter is arranged on the upstream pipeline, and the flow meter is used to measure the flow rate of the fluid in the upstream pipeline;

[0009] The acoustic wave detection mechanism comprises an acoustic wave transmitting probe, an acoustic wave receiving probe, and an acoustic wave positioning probe. The acoustic wave transmitting probe and the acoustic wave receiving probe are respectively fixedly arranged in the upper pressure head and the lower pressure head, and a plurality of the acoustic wave positioning probes are arranged on the surface of the core sample;

[0010] The heating mechanism is arranged outside the protective cover, and the heating mechanism is used to control the temperature in the protective cover.

[0011] The core sample is subjected to pressure by the loading mechanism, wherein pressure is applied to the pressure loading rod by a pressure element, and the pressure loading rod applies axial pressure to the core sample through the upper pressure head, and a liquid with a certain pressure is introduced into the protective cover, and the liquid applies confining pressure to the core sample, thereby effectively restoring the original stress state of the core sample; a fluid is introduced into the upstream pipeline, and the fluid can be a liquid or a gas, and the fluid passes through the core sample and enters the downstream pipeline, so that the permeability of the core sample can be tested, and the damage evolution process of the core sample can be detected by the acoustic wave detection mechanism, and the temperature in the protective cover is kept constant during the test by the heating mechanism.

[0012] Optionally, the upper pressure head and the lower pressure head are both provided with a plurality of annular grooves and a plurality of radial grooves, the annular grooves and the radial grooves are connected to each other, the fluid inlet and the annular grooves on the lower pressure head are connected to the radial grooves, and the fluid outlet and the annular grooves on the lower pressure head are connected to the radial grooves, so as to increase the contact area between the fluid and the core sample and ensure uniform and stable seepage.

[0013] Optionally, a branch pipe is provided on the upstream pipeline, and both ends of the branch pipe are respectively connected to the upstream pipeline on both sides of the flow meter, and a valve is provided on the branch pipe to facilitate switching between non-steady-state permeability test and steady-state permeability test.

[0014] Optionally, the heating mechanism includes a heating pad and a temperature sensor, the heating pad is wrapped around the outside of the protective cover, the temperature sensor is arranged on the inside of the protective cover, the temperature sensor is used to detect the temperature inside the protective cover, the protective cover is heated by the heating pad, and the heat is transferred to the inside of the protective cover through the protective cover.

[0015] Optionally, the dual-channel testing device for damage and permeability evolution of rock materials also includes a nitrogen input module, which is used to input nitrogen into the upstream pipeline and the downstream pipeline. Before the permeability test, nitrogen is introduced into the upstream pipeline and the downstream pipeline to facilitate testing the sealing performance of the permeability testing system.

[0016] Optionally, the elastic sealing layer includes a wrapping portion, a conical portion and a sealing portion, the conical portion and the sealing portion are provided at both ends of the wrapping portion, the conical portion is provided between the wrapping portion and the sealing portion, the sealing portion at one end of the wrapping portion is pressed against the end face of the lower pressure head through a first fastening sleeve, the sealing portion at the other end of the wrapping portion is pressed against the end face of the upper pressure head through a second fastening sleeve, and the conical portion fits with the conical surfaces on the upper pressure head and the lower pressure head respectively. The design of the sealing portion and the conical portion enhances the airtightness of the elastic sealing layer, prevents liquid from entering the core sample when a confining pressure is applied to the core sample, and prevents fluid leakage during a permeability test.

[0017] Optionally, a plurality of first telescopic elements are fixedly mounted in parallel on the lower pressure head, the sealing portion and the first fastening sleeve are fastened to the telescopic ends of the first telescopic elements, and a plurality of second telescopic elements are fixedly mounted on the upper pressure head, the sealing portion and the second fastening sleeve are fastened to the telescopic ends of the second telescopic elements.

[0018] Optionally, the loading mechanism further comprises a fastening rod, the telescopic end of the first telescopic element and the telescopic end of the second telescopic element are both hingedly connected to the fastening rod, and a torsion spring is provided at the hinge of the fastening rod.

[0019] Optionally, the protective cover includes a cover body and a cover cover, the pressure loading rod and the cover cover are slidably matched, one end of the cover body is fixedly connected to the machine base, and the other end of the cover body is fixedly connected to the cover cover, which facilitates the installation of the core sample.

[0020] A dual-channel test method for damage and permeability evolution of rock materials comprises the following steps:

[0021] Permeability non-steady-state method test steps: a fluid with a certain pressure is introduced into the upstream pipeline, and when the value of the upstream pressure sensor reaches the set value, the fluid input is stopped, and the valve is closed so that the upstream reference pressure chamber, the upstream pipeline, the core sample, the downstream reference pressure chamber and the downstream pipeline form a sealed space. Driven by the osmotic pressure, the fluid will flow through the core sample into the downstream reference pressure chamber until the pressure in the upstream reference pressure chamber and the downstream reference pressure chamber reaches a balance. According to the upstream and downstream pressure balance rules, the permeability value can be calculated based on the non-steady-state method test principle;

[0022] Permeability steady-state test steps: the upstream pipeline and the downstream pipeline are connected to the outside world, so that the downstream reference pressure chamber and the upstream reference pressure chamber are balanced with the atmospheric pressure in the chamber, and then the valves of the downstream reference pressure chamber and the upstream reference pressure chamber are closed, so that the upstream reference pressure chamber and the downstream reference pressure chamber are disconnected from the upstream pipeline and the downstream pipeline respectively, and a certain pressure fluid is introduced into the upstream pipeline. After the value of the upstream pressure sensor reaches the specified pressure, this pressure value is stabilized, and the fluid flows through the core sample and is finally discharged from the downstream pipeline. The permeability value can be calculated based on the fluid flow rate and the pressure value in the upstream pipeline and the pressure value in the downstream pipeline.

[0023] The permeability test method can be switched according to the degree of rock damage to ensure the accuracy of the permeability test. It has the advantages of high accuracy and wide test range. In addition, the device can also simultaneously obtain damage-strain, permeability-strain and stress-strain curves, which has certain guiding significance for revealing the rock damage-permeability coupling mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of the structural principle of a dual-channel testing device for damage and permeability evolution of rock materials according to an embodiment of the present invention;

[0025] Figure 2 An exploded diagram of a dual-channel test device for damage and permeability evolution of rock materials according to an embodiment of the present invention;

[0026] Figure 3It is a schematic diagram of the three-dimensional structure of the elastic sealing layer according to an embodiment of the present invention;

[0027] Figure 4 Schematic diagram of the three-dimensional structure of the upper pressure head (or lower pressure head) according to an embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of installing an elastic sealing layer according to an embodiment of the present invention;

[0029] Figure 6 For the embodiment of the present invention Figure 5 Enlarged view of part C in the middle. DETAILED DESCRIPTION

[0030] The specific embodiments of the present invention will be described in detail below. It should be noted that the embodiments described herein are only for illustration and are not intended to limit the present invention. In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is obvious to those of ordinary skill in the art that these specific details do not need to be adopted to implement the present invention. In other examples, in order to avoid confusing the present invention, known circuits, software or methods are not specifically described.

[0031] Throughout the specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment of the present invention. Therefore, the phrases "in one embodiment," "in an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily all refer to the same embodiment or example. In addition, particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combination and / or subcombination. In addition, it should be understood by those of ordinary skill in the art that the figures provided herein are for illustrative purposes and that the figures are not necessarily drawn to scale.

[0032] See also Figure 1-Figure 6 , the present invention provides an embodiment of a dual-channel testing device for damage and permeability evolution of rock materials, comprising: a loading mechanism, a permeability detection mechanism, an acoustic wave detection mechanism and a heating mechanism;

[0033] The loading mechanism includes a pressure loading rod 201, a protective cover 202, an upper pressure head 203 and a lower pressure head 204, wherein the lower pressure head 204 is fixedly mounted on a machine base 205, the upper pressure head 203 and the lower pressure head 204 are arranged opposite to each other, one end of the pressure loading rod 201 is fixedly connected to the upper pressure head 203, and the other end of the pressure loading rod 201 is connected to a pressure element; the pressure element applies axial pressure to the core sample 1, which can simulate the stress failure of the rock, the core sample 1 is fixed between the upper pressure head 203 and the lower pressure head 204, and the outer surface of the core sample 1 is wrapped There is an elastic sealing layer 206, the lower pressure head 204 is provided with a fluid inlet, and the upper pressure head 203 is provided with a fluid outlet. The detection fluid enters from the fluid inlet and passes through the core sample 1 and then flows out from the fluid outlet. The upper pressure head 203 and the lower pressure head 204 are both arranged inside the protective cover 202, and the protective cover 202 is connected to a fluid pump. Liquid or gas with a certain pressure is introduced into the protective cover 202 through the fluid pump, and the liquid or gas can pressurize the core sample 1 in all directions, which can well simulate the original stress state of the core sample 1.

[0034] The permeability detection mechanism includes an upstream pipeline 301, a downstream pipeline 302, an upstream reference pressure chamber 303, a downstream reference pressure chamber 304, an upstream pressure sensor 305, a downstream pressure sensor 306 and a flow meter 307;

[0035] The upstream pipeline 301 is connected to the fluid inlet, the downstream pipeline 302 is connected to the fluid outlet, the upstream reference pressure chamber 303 is connected to the upstream pipeline 301, the downstream reference pressure chamber 304 is connected to the upstream pipeline 301, the upstream pressure sensor 305 is used to measure the fluid pressure in the upstream pipeline 301, the downstream pressure sensor 306 is used to measure the fluid pressure in the downstream pipeline 302, and the flow meter 307 is arranged on the upstream pipeline 301, and the flow meter 307 is used to measure the flow rate of the fluid in the upstream pipeline 301;

[0036] The acoustic wave detection mechanism includes an acoustic wave transmitting probe 402, an acoustic wave receiving probe 401, and an acoustic emission positioning probe 403. The acoustic wave transmitting probe 402 and the acoustic wave receiving probe 401 are fixedly arranged in the upper pressure head 203 and the lower pressure head 204 respectively, and several of the acoustic emission positioning probes 403 are arranged on the surface of the core sample 1; the acoustic emission positioning probe 403 is used to detect the location of damage in the core sample 1.

[0037] The heating mechanism is disposed outside the protection cover 202 , and the heating mechanism is used to control the temperature in the protection cover 202 .

[0038] The core sample 1 is subjected to pressure by the loading mechanism, wherein pressure is applied to the pressure loading rod 201 by a pressure element, and the pressure loading rod 201 applies axial pressure to the core sample 1 through the upper pressure head 203, and a liquid with a certain pressure is introduced into the protective cover 202, and the liquid applies confining pressure to the core sample 1, so that the original stress state of the core sample 1 can be effectively restored; a fluid is introduced into the upstream pipeline 301, and the fluid can be a liquid or a gas, and the fluid passes through the core sample 1 and enters the downstream pipeline 302, so that the permeability of the core sample 1 can be tested, and the damage evolution process of the core sample 1 can be detected by the acoustic wave detection mechanism, and the temperature in the protective cover 202 is kept constant during the test by the heating mechanism.

[0039] In this embodiment, please refer to Figure 1-Figure 4 The upper pressure head 203 and the lower pressure head 204 are both provided with a plurality of annular grooves 2032 and a plurality of radial grooves 2031, the annular grooves 2032 and the radial grooves 2031 are connected to each other, the fluid inlet and the annular grooves 2032 on the lower pressure head 204 are connected to the radial grooves 2031, and the fluid outlet and the annular grooves 2032 on the lower pressure head 204 are connected to the radial grooves 2031. It is used to increase the contact area between the fluid and the core sample 1 to ensure uniform and stable seepage.

[0040] In this embodiment, please refer to Figure 1 A branch pipe 308 is provided on the upstream pipeline 301, and both ends of the branch pipe 308 are respectively connected to the upstream pipeline 301 on both sides of the flow meter 307. A valve is provided on the branch pipe 308 to facilitate the switching between the non-steady-state permeability test and the steady-state permeability test. When the non-steady-state permeability test is performed, the fluid passes through the branch pipe 308, and when the steady-state permeability test is performed, the fluid passes through the flow meter 307.

[0041] In this embodiment, please refer to Figure 1 and Figure 2 The heating mechanism includes a heating pad 501 and a temperature sensor. The heating pad 501 is wrapped around the outside of the protective cover 202. The temperature sensor is arranged on the inside of the protective cover 202. The heating pad 501 is electrically connected to a temperature controller. The temperature sensor is used to detect the temperature inside the protective cover 202. The protective cover 202 is heated by the heating pad 501, and the heat is transferred to the inside of the protective cover 202 through the protective cover 202. The heating mechanism can be used to simulate the ambient temperature in deep formations.

[0042] In this embodiment, please refer to Figure 1 and Figure 2The dual-channel test device for damage and permeability evolution of rock materials also includes a nitrogen input module, which is used to input nitrogen into the upstream pipeline 301 and the downstream pipeline 302. Before the permeability test, nitrogen is introduced into the upstream pipeline 301 and the downstream pipeline 302 to facilitate testing the sealing performance of the permeability test system.

[0043] In this embodiment, please refer to Figure 1-Figure 4 The elastic sealing layer 206 includes a wrapping portion 2061, a conical portion 2062 and a sealing portion 2063. The conical portion 2062 and the sealing portion 2063 are arranged at both ends of the wrapping portion 2061. The conical portion 2062 is arranged between the wrapping portion 2061 and the sealing portion 2063. The sealing portion 2063 at one end of the wrapping portion 2061 is pressed against the end surface of the lower pressure head 204 through the first fastening sleeve 207, and the sealing portion 2063 at the other end of the wrapping portion 2061 is pressed against the end surface of the upper pressure head 203 through the second fastening sleeve 208. The conical portion 2062 is respectively fitted with the conical surfaces 2033 on the upper pressure head 203 and the lower pressure head 204. The sealing portion 2063 and the tapered portion 2062 can enhance the airtightness of the elastic sealing layer 206, prevent liquid from entering the core sample 1 when confining pressure is applied to the core sample 1, and prevent fluid leakage during the permeability test. In the prior art, the elastic sealing layer 206 is installed by wrapping an elastic seal around the outer surface of the core sample 1 and then bonding it with a sealing tape or an adhesive. The two ends of the core sample are then sealed with sealing gaskets and fastening sleeves. The entire assembly process is cumbersome and the seal is prone to leakage. The elastic sealing layer 206 in this embodiment is an integrated structure with good sealing performance and easy installation.

[0044] In this embodiment, please refer to Figure 2 and Figure 3 The wrapping part 2061 is made of a heat shrinkable film. When the wrapping part 2061 is heated, the wrapping part 2061 shrinks due to the heat and tightly wraps the core sample, which has a good sealing effect and is easy to install.

[0045] In this embodiment, please refer to Figure 1 and Figure 2 A plurality of first telescopic elements 209 are fixedly installed in parallel on the lower pressure head 204, the sealing portion 2063 and the first fastening sleeve 207 are fastened to the telescopic end of the first telescopic element 209, and a plurality of second telescopic elements 210 are fixedly installed on the upper pressure head 203, the sealing portion 2063 and the second fastening sleeve 208 are fastened to the telescopic end of the second telescopic element 210, with good sealing performance and easy installation.

[0046] In this embodiment, please refer to Figure 1-Figure 6The loading mechanism further comprises a fastening rod 211, and the telescopic ends of the first telescopic element 209 and the second telescopic element 210 are both hinged with the fastening rod 211, and a torsion spring is arranged at the hinge of the fastening rod 211. After the telescopic end of the first telescopic element 209 passes through the sealing part 2063 and the first fastening sleeve 207 in sequence, the fastening rod 211 rotates under the elastic force of the torsion spring, so that the fastening rod 211 and the first telescopic element 209 are perpendicular, the first telescopic element 209 contracts, the fastening rod 211 presses on the first fastening sleeve 207, and the first fastening sleeve 207 presses the sealing part 2063 tightly on the lower pressure head; similarly, when the second telescopic element 210 contracts, the fastening rod 211 presses on the second fastening sleeve 208, and the second fastening sleeve 208 presses the sealing part 2063 tightly on the upper pressure head. The installation is quick and convenient.

[0047] In this embodiment, please refer to Figure 1 and Figure 2 The protective cover 202 includes a cover body 2022 and a cover 2021. The pressure loading rod 201 and the cover 2021 are slidably matched. One end of the cover body 2022 is fixedly connected to the machine base 205, and the other end of the cover body 2022 is fixedly connected to the cover 2021, which is convenient for the installation of the core sample 1.

[0048] In this embodiment, please refer to Figure 1-Figure 6 The installation steps of the core sample 1 include: sleeve the first fastening sleeve 207 and the second fastening sleeve 208 on the outside of the elastic sealing layer 206, press the first fastening sleeve 207 and the sealing part 2063 on the end surface of the lower pressure head 204, put the core sample into the elastic sealing layer 206, and then press the upper pressure head 203 on the core sample 1, and use the second fastening sleeve 208 to press the elastic sealing layer 206 on the end surface of the upper pressure head 203. The cover body 2021 is fixed on the machine base 205, and the cover cover 2021 is covered. The cover body 2022 is added through the heating pad 501, and the wrapping part 2061 shrinks under heat to tightly wrap the core sample 1. The core sample 1 is easy to install and efficient.

[0049] A dual-channel test method for damage and permeability evolution of rock materials comprises the following steps:

[0050] Permeability non-steady-state test steps: a fluid with a certain pressure is introduced into the upstream pipe 301, and when the value of the upstream pressure sensor 305 reaches the set value, the fluid input is stopped, and the valve is closed to form a sealed space among the upstream reference pressure chamber 303, the upstream pipe 301, the core sample 1, the downstream reference pressure chamber 304 and the downstream pipe 302. Driven by the osmotic pressure, the fluid will flow through the core sample 1 into the downstream reference pressure chamber 304 until the pressure in the upstream reference pressure chamber 303 and the downstream reference pressure chamber 304 reaches a balance. According to the upstream and downstream pressure balance law, the permeability value can be calculated based on the non-steady-state test principle;

[0051] Permeability steady-state test steps: the upstream pipeline 301 and the downstream pipeline 302 are connected to the outside world, so that the downstream reference pressure chamber 304 and the upstream reference pressure chamber 303 are balanced with the indoor atmospheric pressure, and then the valves of the downstream reference pressure chamber 304 and the upstream reference pressure chamber 303 are closed, so that the upstream reference pressure chamber 303 and the downstream reference pressure chamber 304 are disconnected from the upstream pipeline 301 and the downstream pipeline 302 respectively, and a certain pressure fluid is introduced into the upstream pipeline 301. After the value of the upstream pressure sensor 305 reaches the specified pressure, this pressure value is stabilized, and the fluid flows through the core sample 1 and is finally discharged from the downstream pipeline 302. The permeability value can be calculated based on the fluid flow rate and the pressure value in the upstream pipeline 301 and the pressure value in the downstream pipeline 302.

[0052] The permeability test method can be switched according to the degree of rock damage to ensure the accuracy of the permeability test. It has the advantages of high accuracy and wide test range. In addition, the device can also simultaneously obtain damage-strain, permeability-strain and stress-strain curves, which has certain guiding significance for revealing the rock damage-permeability coupling mechanism.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A dual-channel test device for damage and permeability evolution of rock materials, It is characterized in that include: Loading mechanism, The loading mechanism comprises a pressure loading rod, a protective cover, an upper pressure head and a lower pressure head, wherein the lower pressure head is fixedly mounted on a machine base, the upper pressure head and the lower pressure head are arranged opposite to each other, one end of the pressure loading rod is fixedly connected to the upper pressure head, and the other end of the pressure loading rod is connected to a pressure element; a core sample is fixed between the upper pressure head and the lower pressure head, an elastic sealing layer is wrapped on the outer surface of the core sample, a fluid inlet is provided on the lower pressure head, a fluid outlet is provided on the upper pressure head, and a detection fluid enters from the fluid inlet and passes through the core sample and then flows out from the fluid outlet, the upper pressure head and the lower pressure head are both arranged inside the protective cover, and the protective cover is connected to a fluid pump; Permeability testing agency, The permeability detection mechanism includes an upstream pipeline, a downstream pipeline, an upstream reference pressure chamber, a downstream reference pressure chamber, an upstream pressure sensor, a downstream pressure sensor and a flow meter; The upstream pipeline is in communication with the fluid inlet, the downstream pipeline is in communication with the fluid outlet, the upstream reference pressure chamber is in communication with the upstream pipeline, the downstream reference pressure chamber is in communication with the upstream pipeline, the upstream pressure sensor is used to measure the fluid pressure in the upstream pipeline, the downstream pressure sensor is used to measure the fluid pressure in the downstream pipeline, the flow meter is arranged on the upstream pipeline, and the flow meter is used to measure the flow rate of the fluid in the upstream pipeline; Sonic wave detection mechanism, The acoustic wave detection mechanism comprises an acoustic wave transmitting probe, an acoustic wave receiving probe, and an acoustic wave positioning probe. The acoustic wave transmitting probe and the acoustic wave receiving probe are respectively fixedly arranged in the upper pressure head and the lower pressure head, and a plurality of the acoustic wave positioning probes are arranged on the surface of the core sample; Heating mechanism, The heating mechanism is arranged outside the protective cover, and the heating mechanism is used to control the temperature in the protective cover.

2. The dual-channel test device for damage and permeability evolution of rock materials according to claim 1, Features: The upper pressure head and the lower pressure head are both provided with a plurality of annular grooves and a plurality of radial grooves, the annular grooves and the radial grooves are connected to each other, the fluid inlet and the annular grooves on the lower pressure head are connected to the radial grooves, and the fluid outlet and the annular grooves on the lower pressure head are connected to the radial grooves.

3. The dual-channel test device for damage and permeability evolution of rock materials according to claim 1, Features: The upstream pipeline is provided with a branch pipe, both ends of the branch pipe are respectively connected with the upstream pipelines on both sides of the flow meter, and the branch pipe is provided with a valve.

4. The dual-channel test device for damage and permeability evolution of rock materials according to claim 1, Features: The heating mechanism comprises a heating pad and a temperature sensor. The heating pad is wrapped around the outside of the protective cover. The temperature sensor is arranged inside the protective cover. The temperature sensor is used to detect the temperature inside the protective cover.

5. The dual-channel test device for damage and permeability evolution of rock materials according to claim 1, Features: It also includes a nitrogen input module, which is used to input nitrogen into the upstream pipeline and the downstream pipeline.

6. The dual-channel test device for damage and permeability evolution of rock materials according to claim 1, Features: The elastic sealing layer includes a wrapping portion, a conical portion and a sealing portion. The conical portion and the sealing portion are arranged at both ends of the wrapping portion. The conical portion is arranged between the wrapping portion and the sealing portion. The wrapping portion is made of a heat shrinkable film. The sealing portion at one end of the wrapping portion is pressed against the end surface of the lower pressure head through a first fastening sleeve, and the sealing portion at the other end of the wrapping portion is pressed against the end surface of the upper pressure head through a second fastening sleeve. The conical portion is respectively fitted with the conical surfaces on the upper pressure head and the lower pressure head.

7. The dual-channel test device for damage and permeability evolution of rock materials according to claim 6, Features: A plurality of first telescopic elements are fixedly mounted in parallel on the lower pressure head, the sealing portion and the first fastening sleeve are fastened to the telescopic end of the first telescopic element, and a plurality of second telescopic elements are fixedly mounted on the upper pressure head, the sealing portion and the second fastening sleeve are fastened to the telescopic end of the second telescopic element.

8. The dual-channel test device for damage and permeability evolution of rock materials according to claim 7, Features: The loading mechanism further comprises a fastening rod, to which the telescopic end of the first telescopic element and the telescopic end of the second telescopic element are both hinged, and a torsion spring is arranged at the hinge of the fastening rod.

9. The dual-channel test device for damage and permeability evolution of rock materials according to claim 1, Features: The protective cover comprises a cover body and a cover cover, the pressure loading rod and the cover cover are slidably matched, one end of the cover body is fixedly connected to the machine base, and the other end of the cover body is fixedly connected to the cover cover.

10. A dual-channel test method for damage and permeability evolution of rock materials, applicable to the dual-channel test device for damage and permeability evolution of rock materials according to any one of claims 1 to 9, It is characterized in that The steps include: Permeability non-steady-state method test steps: a fluid with a certain pressure is introduced into the upstream pipeline, and when the value of the upstream pressure sensor reaches the set value, the fluid input is stopped, and the valve is closed so that the upstream reference pressure chamber, the upstream pipeline, the core sample, the downstream reference pressure chamber and the downstream pipeline form a sealed space. Driven by the osmotic pressure, the fluid will flow through the core sample into the downstream reference pressure chamber until the pressure in the upstream reference pressure chamber and the downstream reference pressure chamber reaches a balance. According to the upstream and downstream pressure balance rules, the permeability value can be calculated based on the non-steady-state method test principle; Permeability steady-state test steps: the upstream pipeline and the downstream pipeline are connected to the outside world, so that the downstream reference pressure chamber and the upstream reference pressure chamber are balanced with the atmospheric pressure in the chamber, and then the valves of the downstream reference pressure chamber and the upstream reference pressure chamber are closed, so that the upstream reference pressure chamber and the downstream reference pressure chamber are disconnected from the upstream pipeline and the downstream pipeline respectively, and a certain pressure fluid is introduced into the upstream pipeline. After the value of the upstream pressure sensor reaches the specified pressure, this pressure value is stabilized, and the fluid flows through the core sample and is finally discharged from the downstream pipeline. The permeability value can be calculated based on the fluid flow rate and the pressure value in the upstream pipeline and the pressure value in the downstream pipeline.

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