A long core seepage experimental device for simulating coalbed methane reservoirs

Abstract

The present application discloses a long core seepage test device for simulating coalbed methane reservoirs, and belongs to the technical field of core layered seepage test. It includes: a cylinder, a plurality of water outlet interfaces are arranged on the side wall of the cylinder; a sealing cover, the sealing cover is sealed and connected to the cylinder, and a center hole is opened on the sealing cover; a center tube, the first end of the center tube is inserted into the cylinder through the center hole, and a plurality of drainage holes are opened on the tube wall of the center tube located inside the cylinder. The seepage test device provided in the embodiment of the present application can realize liquid injection and drainage of coal rock at different positions by opening a plurality of drainage holes at the layered positions corresponding to the center tube, thereby simulating the interlayer interference of multiple coal seams or the intralayer interference conditions of thick coal seams in the production process, and then the calculated coal rock permeability can be used to analyze the interlayer interference of multiple coal seams and the intralayer interference problems of thick coal seams, thereby improving the accuracy of the data.

Description

Technical Field

[0001] The present application relates to the technical field of core layered seepage experiments, and in particular to a long core seepage experiment device for simulating coalbed methane reservoirs. Background Art

[0002] At present, my country's coalbed methane mining has entered a mature stage. Exploring deep coalbed methane and multi-coal seam development methods is an important topic today. Before effectively evaluating and developing coalbed methane blocks, it is necessary to accurately predict the permeability of coal seams.

[0003] However, the existing coal reservoir permeability prediction and seepage test equipment often only tests a single core, which is not suitable for analyzing the inter-layer interference of multiple coal seams and the intra-layer interference of thick coal seams. When multiple samples need to be tested, the experiment needs to be repeated, which is not only cumbersome, but also difficult to ensure the stability and accuracy of the experimental conditions and samples while disassembling the equipment, which is not conducive to the effective analysis of data. Summary of the invention

[0004] In view of this, the present application provides a long core seepage experimental device for simulating coalbed methane reservoirs.

[0005] Specifically, the following technical solutions are included:

[0006] A long core seepage experimental device for simulating coalbed methane reservoirs is provided, comprising:

[0007] A cylinder, wherein at least one water outlet interface is provided on the side wall of the cylinder, and a flow meter and a first pressure gauge are provided on the water outlet interface;

[0008] A sealing cover, the sealing cover is sealingly connected to the cylinder, and a center hole is opened on the sealing cover;

[0009] A center tube, wherein the first end of the center tube is inserted into the cylinder through the center hole, and the center tube and the center hole are sealedly connected, and at least one drainage hole is provided on the tube wall of the center tube located inside the cylinder; a water inlet interface is connected to the second end of the center tube, and a second pressure gauge is connected to the water inlet interface.

[0010] In a possible implementation manner, a sealing sleeve is provided in the central hole, so that the central tube and the central hole are sealed and rotatably connected;

[0011] The seepage experiment device also includes: a motor, a driving bevel gear and a linkage bevel gear;

[0012] The linkage bevel gear is fixedly sleeved on the central tube, and the linkage bevel gear is close to the upper end surface of the sealing cover; the motor is connected to the sealing cover through a bracket, the driving bevel gear is connected to the rotating shaft of the motor, and the driving bevel gear is meshedly connected to the linkage bevel gear.

[0013] In a possible implementation manner, the seepage experiment device further includes: a connection sleeve;

[0014] An annular groove is arranged on the inner wall of the connection sleeve, and a sliding block is fixedly connected to the central tube. The sliding block can move along the annular groove, so that the central tube can rotate relative to the water inlet interface.

[0015] In a possible implementation manner, the seepage experiment device further includes: a limiting plate;

[0016] The limiting plate is fixedly sleeved on the central tube, and the limiting plate is tightly attached to the lower end surface of the sealing cover.

[0017] In a possible implementation manner, the seepage experiment device further includes: an overflow interface; the overflow interface is arranged on the side wall of the cylinder close to the sealing cover.

[0018] In a possible implementation, a filter screen is provided at a position where the overflow interface is connected to the cylinder.

[0019] In a possible implementation manner, the seepage experiment device further includes: a curved tube, the curved tube being connected to the cylinder through the sealing cover;

[0020] The free end of the curved tube is covered with a pressing plate, and a sliding rod is fixedly connected to the pressing plate;

[0021] The positioning block is fixedly sleeved on the curved tube close to the pressing plate, and a rod sleeve is fixedly connected to the positioning block; the sliding rod and the rod sleeve are slidably sleeved;

[0022] A spring is sleeved on the sliding rod, one end of the spring is connected to the pressing plate, and the other end of the spring is connected to the rod sleeve.

[0023] In a possible implementation manner, three water outlet interfaces are provided on the side wall of the cylinder, and three pairs of drainage holes are opened on the wall of the central tube;

[0024] The three water outlet interfaces correspond to the three pairs of drainage holes respectively.

[0025] In a possible implementation manner, the intervals between two adjacent pairs of drainage holes in the three pairs of drainage holes are equal.

[0026] In a possible implementation manner, the free end of the water outlet interface is connected to a transition interface via a flange;

[0027] The second pressure gauge is arranged on the transition interface.

[0028] The beneficial effects of the technical solution provided by the embodiments of the present application include at least:

[0029] The seepage experiment device provided in the embodiment of the present application can realize the injection and drainage of coal rocks at different positions by opening multiple drainage holes at the layered positions corresponding to the central pipe, thereby simulating the interlayer interference of multiple coal seams or the intralayer interference conditions of thick coal seams in the production process, and then the calculated coal rock permeability can be used to analyze the interlayer interference of multiple coal seams and the intralayer interference problems of thick coal seams, thereby improving the accuracy of the data. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 A schematic diagram of the structure of a long core seepage experimental device for simulating coalbed methane reservoirs provided in an embodiment of the present application;

[0032] Figure 2 for Figure 1 An enlarged schematic diagram of the middle connection sleeve;

[0033] Figure 3 for Figure 1 Enlarged schematic diagram of the medium pressure plate.

[0034] The reference numerals in the figures represent respectively:

[0035] 1-Cylinder;

[0036] 2- Water outlet interface;

[0037] 3- Flow meter;

[0038] 4-First pressure gauge;

[0039] 5- Sealing cover;

[0040] 6- Water inlet interface;

[0041] 7-Center hole;

[0042] 8-Center tube;

[0043] 9- Drainage hole;

[0044] 10- Second pressure gauge;

[0045] 11- Motor;

[0046] 12-driving bevel gear;

[0047] 13-linked bevel gear;

[0048] 14-connection sleeve;

[0049] 15- annular groove;

[0050] 16- Slider;

[0051] 17-Limiting plate;

[0052] 18- Overflow interface;

[0053] 19-Filter;

[0054] 20-curved tube;

[0055] 21-pressing plate;

[0056] 22- Slider;

[0057] 23- rod sleeve;

[0058] 24-spring;

[0059] 25- positioning block;

[0060] 26-transition interface;

[0061] X-coal rock sample.

[0062] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0063] Unless otherwise defined, all technical terms used in the embodiments of the present application have the same meanings as those generally understood by those skilled in the art. To make the technical solutions and advantages of the present application clearer, the embodiments of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0064] The present application embodiment provides a long core seepage experimental device for simulating coalbed methane reservoirs, such as Figure 1 As shown, the seepage experiment device comprises: a cylinder 1, a plurality of water outlet interfaces 2 are arranged on the side wall of the cylinder 1, and a flow meter 3 and a first pressure gauge 4 are arranged on the water outlet interfaces 2;

[0065] A sealing cover 5, the sealing cover 5 is sealingly connected to the cylinder 1, and a central hole 7 is opened on the sealing cover 5;

[0066] A center tube 8, the first end of the center tube 8 is inserted into the cylinder 1 through the center hole 7, and the center tube 8 and the center hole 7 are sealed and connected, and a plurality of drainage holes 9 are opened on the tube wall of the center tube 8 located inside the cylinder 1; a water inlet interface 6 is connected to the second end of the center tube 8, and a second pressure gauge 10 is connected to the water inlet interface 6.

[0067] When in use, first fill the coal rock sample X into the cylinder 1 according to the required combination form, and open a channel compatible with the center tube 8 in the middle position; fix the sealing cover 5 on the cylinder 1, insert the center tube 8 into the channel of the coal rock sample X through the center hole 7 on the sealing cover 5, and then connect the water inlet interface 6 and the water outlet interface 2 with the corresponding hard stainless steel pipes to ensure the flow of the test liquid, and then pump the test liquid into the center tube 8 through the water inlet interface 6 through an external water pump, the test liquid enters the wellbore 1 to infiltrate the coal rock sample X, and flows out from the water outlet interface 2.

[0068] When the injection and seepage of the experimental device reach a steady state, the permeability of the coal rock sample can be calculated by K=(QμL) / A(p1-p2), where k is the coal rock permeability; Q is the sum of the liquid flow rates at multiple water outlet interfaces, which can be measured by the flowmeter 3; μ is the fluid viscosity of the liquid in the test; L is the length of the coal rock sample in the cylinder; A is the sum of the cross-sectional areas of multiple water outlet interfaces; p1 is the inlet pressure, which can be measured by the second pressure gauge 10; p2 is the outlet pressure, which can be measured by the first pressure gauge 4.

[0069] The seepage experiment device provided in the embodiment of the present application can realize the injection and drainage of coal rocks at different positions by opening multiple drainage holes at the layered positions corresponding to the central pipe, thereby simulating the interlayer interference of multiple coal seams or the intralayer interference conditions of thick coal seams in the production process, and then the calculated coal rock permeability can be used to analyze the interlayer interference of multiple coal seams and the intralayer interference problems of thick coal seams, thereby improving the accuracy of the data.

[0070] In the above-mentioned seepage experimental device, the sealing cover 5 is sealed to the barrel 1. The embodiment of the present application does not strictly limit the connection relationship between the two, as long as the sealing can be achieved. In a possible implementation, the sealing cover 5 can be connected to the barrel 1 by threads. For example, an external thread can be set on the sealing cover 5, and an internal thread can be set on the barrel 1.

[0071] Furthermore, a sealing gasket may be provided between the seal 5 and the cylinder 1 to enhance the sealing effect therebetween.

[0072] The flow meter and the pressure gauge are used to measure the fluid flow and fluid pressure, respectively. The embodiments of the present application do not strictly limit the models of the flow meter and the pressure gauge, as long as they can meet the measurement requirements. For example, a flow meter and a pressure gauge with a digital display function can be used. For example, the model of the flow meter 3 can be DN25, and the model of the first pressure gauge 4 and the model of the second pressure gauge 10 can both be AZ82100.

[0073] The drainage holes 9 are arranged on the wall of the central tube 8. The present application simulates the interference between multiple coal seams or the interference within thick coal seams during the production process by arranging multiple pairs of drainage holes 9. The embodiment of the present application does not strictly limit the number of drainage holes 9, and can be selected according to actual conditions.

[0074] In a possible embodiment, Figure 1 As shown, three pairs of drainage holes 9 can be opened on the wall of the central pipe 8 to simulate the interference between the three coal seams. At the same time, correspondingly, three water outlet interfaces 2 can be set on the side wall of the cylinder 1, and the three water outlet interfaces 2 correspond to the three pairs of drainage holes 9 respectively. The water outlet interfaces 2 can ensure the normal injection and discharge of the corresponding drainage holes 9, making the simulated conditions closer to the real situation.

[0075] It is understandable that each pair of drainage holes 9 can be arranged relatively on the wall of the central tube. Such arrangement allows the test fluid to evenly infiltrate the coal rock sample. In order to achieve a better simulation effect, the spacing between the three water outlet interfaces 2 can also be made the same and on the same straight line with the positions of the corresponding drainage holes 9.

[0076] The three water outlet interfaces 2 are respectively connected with a flow meter 3 and a first pressure gauge 4 to measure the flow rate and pressure of the corresponding outlets.

[0077] In addition, the number of the drainage holes 9 can be set to 2 pairs, 4 pairs, 5 pairs, etc., which can be set and selected according to actual conditions.

[0078] In a possible implementation, in order to facilitate the discharge of water at the water outlet interface 2 , in a possible real-time manner, the free end of the water outlet interface 2 can be connected to the transition interface 26 ; the second pressure gauge 10 is disposed on the transition interface 26 .

[0079] When used, the transition interface 26 can be connected to a corresponding hard stainless steel pipe to ensure the flow of water.

[0080] The embodiment of the present application does not strictly limit the connection method between the water outlet interface 2 and the transition interface 26, as long as a sealed connection between the two can be achieved. In a possible implementation, the free end of the water outlet interface 2 can be connected to the transition interface 26 through a flange.

[0081] In the above-mentioned seepage test device, in order to further ensure that the test fluid infiltrates the coal rock sample, the central tube 8 is rotated relative to the coal rock sample during the injection process. By rotating the central tube 8, the water pressure impact force and impact surface on the coal rock sample X can be increased, so that the test fluid can enter the coal rock sample faster and more effectively.

[0082] In a possible implementation, a sealing sleeve is provided in the center hole 7, and the center tube 8 is sealedly connected to the center hole 7 through the sealing sleeve. Providing the sealing sleeve can not only realize the sealed connection between the center hole 7 and the center tube 8, but also will not affect the rotation of the center tube 8 relative to the center hole 7. In a possible implementation, the sealing sleeve can be a sealing rubber gasket.

[0083] Furthermore, in order to realize the rotation of the central tube 8 relative to the coal rock sample, as Figure 1 As shown, the seepage experiment device can also include: a motor 11, a driving bevel gear 12 and a linkage bevel gear 13; the linkage bevel gear 13 is fixedly sleeved on the central tube 8, and the linkage bevel gear 13 is close to the upper end surface of the sealing cover 5; the motor 11 is connected to the sealing cover 5, the driving bevel gear 12 is connected to the rotating shaft of the motor 11, and the driving bevel gear 12 is meshed and connected to the linkage bevel gear 13.

[0084] When in use, the motor 11 is turned on, so that the motor 11 drives the driving bevel gear 12 to rotate, so that the driving bevel gear 12 engages with the linkage bevel gear 13 to rotate, and the linkage bevel gear 13 drives the center tube 8 to rotate. The rotation of the center tube 8 can further rotate the drainage hole 9, thereby realizing rotational water spraying, thereby increasing the water pressure impact on the coal rock sample X. After the impact is completed, the test liquid will flow out from the three water outlet interfaces 2.

[0085] In the embodiment of the present application, the central tube 8 is rotated to cause the drainage holes 9 to rotate and spray water, thereby achieving uniform pressure on the rock sample and further improving the accuracy of the experiment.

[0086] The embodiment of the present application does not strictly limit the connection method between the electrode 11 and the sealing cover 5, as long as the above connection can be achieved. In a possible real-time method, the electrode 11 can be connected to the sealing cover 5 through a bracket.

[0087] In addition, the embodiment of the present application does not strictly limit the model of the electrode 11, as long as it can achieve the above functions. For example, the model of the motor 11 can be 51K90GU-C, and the motor 11 can be fixedly connected to the indoor power socket through a wire plug.

[0088] In the above-mentioned seepage experimental device, the linkage bevel gear 13 is fixedly connected to the central tube 8 and is close to the sealing cover 5, that is, during operation, the linkage bevel gear 13 drives the central tube 8 to rotate relative to the sealing cover 5. Based on this, lubricating grease can be applied between the linkage bevel gear 13 and the sealing cover 5 to reduce the friction resistance between the two and ensure the smooth rotation of the central tube 8.

[0089] During the above rotation process, the water inlet interface 6 can rotate together with the central tube 8. Considering the convenience of water injection, the water inlet interface 6 can also be kept fixed and the central tube 8 can rotate relative to the water inlet interface 6.

[0090] In order to realize the rotation of the central tube 8 relative to the water inlet interface 6 , the seepage experiment device may include a connection sleeve 14 , through which the central tube 8 is rotatably connected to the water inlet interface 6 .

[0091] Specifically, an annular groove 15 may be provided on the inner wall of the connecting sleeve 14 , and a slider 16 may be fixedly connected to the central tube 8 . The slider 16 may move along the annular groove 15 , so that the central tube 8 may rotate relative to the water inlet interface 6 .

[0092] like Figure 2 As shown, a connection sleeve 14 is provided at the upper end of the central tube 8, a water inlet interface 6 is embedded in the connection sleeve 14, a second pressure gauge 10 is embedded in the water inlet interface 6, an annular groove 15 is provided on the connection sleeve 14, a slider 16 is fixedly connected to the central tube 8, the slider 16 is slidably connected to the annular groove 15, and the connection sleeve 14 can be a half-spliced ​​structure. The water inlet interface 6 is connected to the external hard stainless steel pipe flange, which is used to pump in the test liquid through a water pump and ensure the water supply pressure. At the same time, through the rotation of the central tube 8, the drainage hole 9 can rotate to drain water, thereby improving the water pressure effect on the coal rock sample X.

[0093] The embodiment of the present application does not strictly limit the shape of the connection sleeve 14, which can be a regular shape, such as a square or a circle; or an irregular shape.

[0094] In the above-mentioned seepage experimental device, Figure 1 As shown, it also includes a limiting plate 17 ; the limiting plate 17 is fixedly sleeved on the central tube 8 , and the limiting plate 17 is in close contact with the lower end surface of the sealing cover 5 .

[0095] In the above-mentioned seepage experimental device, the limiting plate 17 is fixedly connected to the central tube 8 and is close to the sealing cover 5, that is, during operation, the central tube 8 drives the limiting plate 17 to rotate relative to the sealing cover 5. Based on this, lubricating grease can be applied between the limiting plate 17 and the sealing cover 5 to reduce the friction resistance between the two and ensure the smooth rotation of the central tube 8.

[0096] In the process of pumping the test liquid, in order to promptly remove the overflow liquid, the seepage experiment device can also include an overflow interface 18, which can be arranged on the side wall of the cylinder 1 near the sealing cover 5. Figure 1 As shown, it can be arranged on the side wall of the cylinder 1 corresponding to the limiting plate 17.

[0097] When in use, the overflow interface 18 is connected to a corresponding hard stainless steel pipe to ensure the flow of overflow liquid.

[0098] Furthermore, a filter screen 19 may be provided at the position where the overflow interface 18 is connected to the cylinder 1. The filter screen 19 may intercept the coal seam sample X to prevent the sample from flowing out.

[0099] like Figure 1 As shown, the cylinder 1 is filled with a coal rock sample X, the upper end surface of the coal rock sample X is in contact with the limit plate 17, an overflow interface 18 is embedded in the cylinder 1, and a filter screen 19 is fixedly connected to the contact position between the overflow interface 18 and the cylinder 1, which can discharge the overflowed liquid when the test liquid is injected.

[0100] During the process of injecting liquid, the pressure inside the cylinder 1 will increase. In order to prevent the cylinder 1 from bursting, the pressure inside the cylinder 1 can also be released.

[0101] In order to achieve the above purpose, Figure 1 and 3 As shown, the seepage experiment device includes a curved tube 20, which is connected to the cylinder 1 through a sealing cover 5; the free end of the curved tube 20 is covered with a pressure plate 21, and a slide rod 22 is fixedly connected to the pressure plate 21; a positioning block 25 is fixedly sleeved on the curved tube 20 close to the pressure plate 21, and a rod sleeve 23 is fixedly connected to the positioning block 25; the slide rod 22 and the rod sleeve 23 are slidably sleeved; a spring 24 is sleeved on the slide rod 22, one end of the spring 24 is connected to the pressure plate 21, and the other end of the spring 24 is connected to the rod sleeve 23.

[0102] During application, when the air pressure in the cylinder 1 exceeds a preset value, the air pressure will be discharged through the curved tube 20 to push open the pressure plate 21; when the air pressure in the cylinder 1 is less than the preset value, the pressure plate 21 can be reset by the spring 24 so that the pressure plate 21 can cover the curved tube 20 again.

[0103] The embodiment of the present application can prevent the situation in which the air pressure introduced during water supply cannot be discharged and causes the sealed cylinder to burst through the pressure relief effect of the curved tube.

[0104] In a possible implementation, Figure 1 As shown in FIG. 1 , the specific implementation process of the seepage experimental device is as follows:

[0105] First, fill the coal rock sample X into the cylinder 1 according to the required combination form, and open a channel adapted to the central tube 8 in the middle position; fix the sealing cover 5 with the central tube 8 to the cylinder 1, and insert the central tube 8 into the channel of the rock sample X; connect the overflow interface 18, the water inlet interface 6, and the transition interface 26 to the corresponding hard stainless steel pipes to ensure the flow of water; pump the test liquid into the central tube 8 through an external water pump, adjust the water supply speed of the water pump according to the second pressure gauge 10, and turn on the motor 11 at the same time, so that the motor 11 drives the driving bevel gear 12 to rotate, so that the driving bevel gear 12 engages with the linkage bevel gear 13 to rotate, realizes the rotation of the central tube 8, and then enables the drainage hole 9 to rotate and spray water; after the impact is completed, the test liquid will flow out from the three water outlet interfaces 2, the flow rate is detected by the flow meter 3, and the water outlet pressure is detected by the first pressure gauge 4 on the transition interface 26, and then the permeability of the rock is calculated by the formula K=(QμL) / A(p1-p2).

[0106] When the air pressure in the cylinder 1 is too high, the air pressure will pass through the curved tube 20, push open the pressure plate 21 and be discharged, and the pressure plate 21 can cover the curved tube 20 again through the restoring action of the spring 24.

[0107] The seepage experiment device provided in the embodiment of the present application can realize the injection and drainage of coal rocks at different positions by opening multiple drainage holes at the layered positions corresponding to the central pipe, thereby simulating the interlayer interference of multiple coal seams or the intralayer interference conditions of thick coal seams in the production process, and then the calculated coal rock permeability can be used to analyze the interlayer interference of multiple coal seams and the intralayer interference problems of thick coal seams, thereby improving the accuracy of the data.

[0108] In the present application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The term "plurality" refers to two or more than two, unless otherwise clearly defined.

[0109] The above description is only for the purpose of facilitating those skilled in the art to understand the technical solution of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A long core seepage test device for simulating coalbed methane reservoirs, characterized in that: include: A cylinder (1), wherein a plurality of water outlet interfaces (2) are arranged on a side wall of the cylinder (1), and a flow meter (3) and a first pressure gauge (4) are arranged on the water outlet interfaces (2); a sealing cover (5), the sealing cover (5) being sealingly connected to the cylinder (1), the sealing cover (5) being provided with a center hole (7), the center hole (7) being provided with a sealing sleeve, so that the center tube (8) and the center hole (7) are sealed and rotatably connected; a central tube (8), wherein a first end of the central tube (8) is inserted into the cylinder (1) through the central hole (7), and the central tube (8) and the central hole (7) are sealedly connected, and a plurality of drainage holes (9) are provided on a tube wall of the central tube (8) located inside the cylinder (1); a water inlet interface (6) is connected to the second end of the central tube (8), and a second pressure gauge (10) is connected to the water inlet interface (6); A motor (11), a driving bevel gear (12) and a linkage bevel gear (13); The linkage bevel gear (13) is fixedly sleeved on the central tube (8), and the linkage bevel gear (13) is in close contact with the upper end surface of the sealing cover (5); the motor (11) is connected to the sealing cover (5) via a bracket, the driving bevel gear (12) is connected to the rotating shaft of the motor (11), and the driving bevel gear (12) is meshedly connected to the linkage bevel gear (13); A connecting sleeve (14), wherein an annular groove (15) is provided on the inner wall of the connecting sleeve (14), a slider (16) is fixedly connected to the central tube (8), and the slider (16) can move along the annular groove (15), so that the central tube (8) can rotate relative to the water inlet interface (6); a curved tube (20), the curved tube (20) being in communication with the cylinder (1) through the sealing cover (5); The free end of the curved tube (20) is covered with a pressing plate (21), and a sliding rod (22) is fixedly connected to the pressing plate (21); A positioning block (25) is fixedly sleeved on the curved tube (20) near the pressing plate (21), and a rod sleeve (23) is fixedly connected to the positioning block (25); the sliding rod (22) and the rod sleeve (23) are slidably sleeved; A spring (24) is sleeved on the sliding rod (22); one end of the spring (24) is connected to the pressing plate (21), and the other end of the spring (24) is connected to the rod sleeve (23).

2. The seepage experiment device according to claim 1, characterized in that: Also includes a limit plate (17); The limiting plate (17) is fixedly sleeved on the central tube (8), and the limiting plate (17) is in close contact with the lower end surface of the sealing cover (5).

3. The seepage experiment device according to claim 1, characterized in that: It also includes an overflow interface (18); the overflow interface (18) is arranged on the side wall of the cylinder (1) close to the sealing cover (5).

4. The seepage experiment device according to claim 3, characterized in that: A filter screen (19) is provided at a position where the overflow interface (18) is in communication with the cylinder (1).

5. The seepage experiment device according to claim 1, characterized in that: The side wall of the cylinder (1) is provided with three water outlet interfaces (2), and the wall of the central tube (8) is provided with three pairs of drainage holes (9); The three water outlet interfaces (2) correspond to three pairs of drainage holes (9) respectively.

6. The seepage experiment device according to claim 5, characterized in that: The spacing between two adjacent pairs of drainage holes (9) in the three pairs of drainage holes (9) is equal.

7. The seepage experiment device according to claim 5, characterized in that: The free end of the water outlet interface (2) is connected to a transition interface (26) via a flange; The second pressure gauge (10) is arranged on the transition interface (26).

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