Coal bed gas shaft pulverized coal migration and settlement test system
By combining a simulated wellbore and a tuning fork resonant sensor, the problem of difficult monitoring of coal dust migration and settling in coalbed methane wellbores was solved, providing experimental data support and reducing the occurrence of downhole faults.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHINA UNITED COALBED METHANE
- Filing Date
- 2025-06-27
- Publication Date
- 2026-05-26
AI Technical Summary
During coalbed methane extraction, the migration and settling of coal powder can lead to downhole malfunctions such as pump jamming and low pump efficiency. The lack of systematic experimental research methods and data support makes it difficult to effectively prevent and control these problems.
A coalbed methane wellbore coal powder migration and settling test system is provided, including a simulated wellbore, a liquid injection system, a gas injection system, and a tuning fork resonant sensor. The system simulates the coal powder migration and settling process inside wellbores of different types and acquires experimental data through the tuning fork resonant sensor.
This provides experimental data support for the migration and settling of pulverized coal inside wells of different well types, optimizes engineering practices, and reduces the occurrence of downhole failures.
Smart Images
Figure CN224285911U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of coalbed methane development technology, and in particular to a coalbed methane wellbore coal powder migration and settling test system. Background Technology
[0002] Coalbed methane (CBM), as an important unconventional natural gas resource, possesses three major attributes: energy, safety, and environmental protection. In the process of CBM extraction, vertical wells, directional wells, and horizontal wells are the three most commonly used CBM production well types in the field. The drainage and extraction of CBM from different well types generally utilizes the principle of depressurization, which achieves gas-water separation and extraction by continuously draining water to reduce the pressure within the formation.
[0003] However, during the drainage process, coal dust generated in the coal seam enters the wellbore along with the gas-water mixture. As water production decreases, the coal dust in the reservoir settles. Due to the complex internal structure and flow patterns of various well types, the migration and settlement of coal dust can easily lead to downhole malfunctions such as pump jamming and low pump efficiency, shortening the production time of coalbed methane wells and increasing the number and cost of well workover operations. Currently, the understanding of the patterns of coal dust migration and settlement within different well types is still insufficient, lacking systematic experimental research methods and data support, making it difficult to take targeted and effective control measures in engineering practice.
[0004] Therefore, there is an urgent need to develop a coalbed methane wellbore coal powder migration and settling test system to solve the above-mentioned technical problems. Utility Model Content
[0005] The purpose of this invention is to provide a coalbed methane wellbore coal powder migration and settling test system that can simulate coal powder migration and settling inside wellbores of different types, thereby providing experimental data support for coal powder migration and settling inside wellbores of different types.
[0006] To achieve this objective, the present invention adopts the following technical solution:
[0007] This utility model provides a coalbed methane wellbore coal powder migration and settling test system, including:
[0008] The simulated wellbore includes an inner tubing string and an outer tubing string, with an annular space between the inner tubing string and the outer tubing string, and the annular space is interconnected with the inner tubing string. The simulated wellbore can rotate and tilt within a preset angle around its own center.
[0009] The liquid injection system is connected to the first end of the annular section, and the liquid injection system is used to inject coal powder slurry into the annular section.
[0010] The gas injection system is connected to the second end of the annulus. The gas injection system is used to input simulated gas into the annulus. The second end and the first end are located at opposite ends of the annulus along its own length. Both the simulated gas and the coal slurry can flow from the annulus to the inner tubular column and return to the injection system.
[0011] A tuning fork resonant sensor is installed in the simulated wellbore. The fork of the tuning fork resonant sensor is located inside the inner tubing. The fork is used to detect the vibration frequency of the coal slurry and the simulated gas when they flow inside the inner tubing.
[0012] In some embodiments, the coalbed methane wellbore coal powder migration and settling test system further includes a hollow mounting bracket with a receiving space. The simulated wellbore is at least partially located within the receiving space. A rotating shaft is fixedly connected to the outer peripheral surface at the center of the simulated wellbore. The rotating shaft is rotatably connected to the mounting bracket and is capable of rotating relative to the mounting bracket about its own axis.
[0013] In some embodiments, two rotating shafts are provided, and the central axes of the two rotating shafts are collinear and perpendicular to the central axis of the simulated wellbore.
[0014] In some embodiments, the walls of both the inner and outer tubing layers are made of transparent material.
[0015] In some embodiments, the coalbed methane wellbore coal powder migration and settling test system further includes a camera device disposed on the outside of the mounting bracket, the camera device being used to acquire images of coal powder inside the simulated wellbore.
[0016] In some embodiments, the camera device includes a guide rail and a camera, the guide rail being spaced apart from the mounting bracket and extending vertically, and the camera being movably connected to the guide rail.
[0017] In some embodiments, the injection system includes a mixing tank and a screw pump, the mixing tank being used to form and contain the pulverized coal slurry, and the screw pump being connected between the mixing tank and the annulus.
[0018] In some embodiments, the gas injection system includes a gas storage device and an air compressor, the gas storage device being used to contain the simulated gas, and the air compressor being connected between the gas storage device and the annulus.
[0019] In some embodiments, the inner tube column has a plurality of through-holes on its tube wall, and the annular portion and the inner tube column are interconnected through the plurality of through-holes.
[0020] In some embodiments, the tuning fork resonant sensor includes a mounting sleeve and a sensor body. The mounting sleeve is connected through the simulated wellbore, and the sensor body is partially connected inside the mounting sleeve. The mounting sleeve has a through hole that connects the mounting sleeve to the inner tubing string, and the fork of the sensor body is located inside the through hole.
[0021] The beneficial effects of this utility model are:
[0022] The coalbed methane wellbore coal powder migration and settling test system provided by this utility model can simulate and reproduce the coal powder migration and settling process inside the simulated wellbore through a liquid injection system and a gas injection system. It can also acquire coal powder migration and settling data through a tuning fork resonant sensor. Furthermore, the simulated wellbore can rotate and tilt to simulate coal powder migration and settling inside wellbores of different types. This provides experimental data support for coal powder migration and settling inside wellbores of different types, which is beneficial for optimizing actual operations in engineering practice and reducing the occurrence of downhole failures. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this utility model and these drawings without creative effort.
[0024] Figure 1 This is a three-dimensional structural schematic diagram of the coalbed methane wellbore coal powder migration and settling test system provided in this embodiment of the utility model;
[0025] Figure 2 This is a front view of the coalbed methane wellbore coal powder migration and settling test system provided in this embodiment of the utility model;
[0026] Figure 3 This is a schematic diagram of the structure of the simulated well shaft and mounting bracket provided in this embodiment of the utility model;
[0027] Figure 4 This is a schematic diagram of the structure of the simulated wellbore provided in this embodiment of the utility model;
[0028] Figure 5 This is a cross-sectional view of the simulated wellbore provided in an embodiment of the present invention;
[0029] Figure 6 yes Figure 5 A partial cross-sectional view of the middle tuning fork resonator sensor.
[0030] In the picture:
[0031] 1. Simulated wellbore; 11. Inner tubing string; 111. Screen; 12. Outer tubing string; 13. Annulus; 131. First end; 132. Second end; 14. Rotating shaft;
[0032] 2. Liquid injection system; 21. Mixing tank;
[0033] 3. Gas injection system; 31. Gas storage device;
[0034] 4. Tuning fork resonant sensor; 41. Fork body; 42. Mounting sleeve; 421. Through hole; 43. Sensor body;
[0035] 5. Install brackets; 51. Accommodation space;
[0036] 6. Camera device; 61. Guide rail; 62. Camera. Detailed Implementation
[0037] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0038] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0039] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0040] In the description of this utility model, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.
[0041] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0042] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0043] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.
[0044] like Figures 1-6 As shown, this embodiment provides a coalbed methane wellbore coal powder migration and settling test system, including a simulated wellbore 1, a liquid injection system 2, a gas injection system 3, and a tuning fork resonant sensor 4.
[0045] The simulated wellbore 1 includes an inner tubing string 11 and an outer tubing string 12, with an annulus 13 between them. The annulus 13 is interconnected with the inner tubing string 11. The simulated wellbore 1 can rotate and tilt within a preset angle around its center. Specifically, the simulated wellbore 1 can rotate according to the different inclination angles of vertical, directional, and horizontal wells. The outer tubing string 12 simulates the production casing of a coalbed methane well in the field, and the inner tubing string 11 simulates the oil tubing of a coalbed methane well in the field. The dimensions of the simulated wellbore 1 can be set according to the actual needs of the field.
[0046] The liquid injection system 2 is connected to the first end 131 of the annular section 13. The liquid injection system 2 is used to inject pulverized coal slurry into the annular section 13. Pulverized coal slurry refers to the liquid obtained by uniformly mixing pulverized coal and water. The gas injection system 3 is connected to the second end 132 of the annular section 13. The gas injection system 3 is used to inject simulated gas into the annular section 13. The second end 132 and the first end 131 are located at opposite ends of the annular section 13 along its length. Both the simulated gas and the pulverized coal slurry can flow from the annular section 13 to the inner tubular column 11 and return to the liquid injection system 2. It is understood that liquid and gas transfer can be achieved between the liquid injection system 2 and the annular section 13, and between the gas injection system 3 and the annular section 13 via connecting pipelines (not shown in the diagram).
[0047] The tuning fork resonant sensor 4 is installed in the simulated wellbore 1. The fork body 41 of the tuning fork resonant sensor 4 is located inside the inner tubing 11. The fork body 41 is used to detect the vibration frequency of the coal powder slurry and simulated gas flowing inside the inner tubing 11.
[0048] In practice, the simulated wellbore 1 is first rotated to a preset angle, and after being rotated to the preset angle, the simulated wellbore 1 remains relatively fixed. Figure 1 Taking the shown orientation as an example, the simulated wellbore 1 is rotated and fixed in a vertical well configuration. The injection system 2 and gas injection system 3 are activated, allowing pulverized coal slurry to be injected into the annulus 13 from the first end 131, and simulated gas to be injected into the annulus 13 from the second end 132. The pulverized coal slurry and simulated gas entering the annulus 13 flow into the inner tubing string 11 and move within it until returning to the injection system 2. This allows the pulverized coal slurry and simulated gas to form a continuous circulation within the simulated wellbore 1. Preferably, combined with... Figure 5The first end 131 is the top end of the annulus 13, and the second end 132 is the bottom end of the annulus 13. In this way, the coal slurry is injected from the top of the annulus 13, flows downward and flows into the inner tubing 11, and the simulated gas is injected from the bottom of the annulus 13. After flowing into the inner tubing 11, the simulated gas moves upward and forms a gas-liquid mixture with the coal slurry in the inner tubing 11. Due to the gas lift effect of the simulated gas, the gas-liquid mixture flows upward in the inner tubing 11 (simulating the actual wellbore flowback process). During this process, the coal powder will undergo suspension, sedimentation and other movement. Finally, the gas-liquid mixture can return from the top of the inner tubing 11 to the injection system 2 for cyclic injection.
[0049] The tuning fork resonant sensor 4 serves as the data acquisition device for the coal dust migration and settling test system in this coalbed methane wellbore. The fork body 41 is located inside the inner tubing 11. When the fluid flows inside the inner tubing 11, it passes through the fork body 41. When the fluid being measured flows through the fork body 41, a resonance phenomenon occurs. The fork body 41 has a stable natural resonant frequency in its initial state. Since different densities of fluid will produce different vibration frequencies when flowing through the fork body 41, it is only necessary to detect the vibration frequency when the fluid flows through the fork body 41 to calculate the fluid density value. In practical applications, the fluid concentration is often required rather than the density. Therefore, the fluid concentration value can be further deduced from the fluid density value. During the experiment, it is necessary to observe the stability of the data collected by the tuning fork resonant sensor 4. Data recording begins after the data stabilizes.
[0050] The relationship between the density of the fluid being measured and the vibration frequency is as follows:
[0051] ρ=K0+K1T+K2T2
[0052] Where: ρ—density of the fluid being measured, g / cm³ 3 K0, K1, K2—coefficients of the tuning fork resonant sensor, which need to be calibrated; T—natural frequency of the fork body 41, Hz; T2—vibration frequency of the fluid being measured passing through the fork body 41, Hz.
[0053] Furthermore, the conversion relationship between fluid density and concentration is as follows:
[0054]
[0055] Where: C—concentration of the fluid being measured, g / cm³ 3 ρ0—density of pulverized coal, g / cm³ 3 ;ρ c —Density of water, g / cm³ 3 .
[0056] In the tuning fork resonant sensor 4, the root of the fork 41 has an excitation coil responsible for exciting vibration; the piezoelectric device at the other end of the fork 41 is responsible for detecting the vibration frequency; the circuit at the top amplifies the signal, thereby accurately measuring the vibration frequency of the fork 41. The tuning fork resonant sensor 4 is a mature existing technology in this field, and its detailed measurement principle will not be elaborated here.
[0057] The coalbed methane wellbore coal powder migration and settling test system provided in this embodiment can simulate and reproduce the coal powder migration and settling process inside the simulated wellbore 1 through the liquid injection system 2 and the gas injection system 3. It can also acquire coal powder migration and settling data through the tuning fork resonant sensor 4. Furthermore, the simulated wellbore 1 can rotate and tilt to simulate coal powder migration and settling inside wellbores of different types. This provides experimental data support for coal powder migration and settling inside wellbores of different types, which is beneficial for optimizing actual operations in engineering practice and reducing the occurrence of downhole failures.
[0058] Optionally, the preset angle is set to 0° to 90°. Figure 1 Taking the orientation state shown as an example, when the simulated well shaft 1 is in a vertical well state, it is the reference state of rotation and tilt, and the preset angle is 0°. When the preset angle is 90°, the simulated well shaft 1 rotates from the vertical well state to the horizontal well state. When the preset angle is between 0° and 90°, it corresponds to the state of the simulated well shaft 1 as a directional well. For example, when the preset angle is 45°, the simulated well shaft 1 corresponds to a 45° directional well.
[0059] like Figure 6 As shown, in some embodiments, the tuning fork resonant sensor 4 includes a mounting sleeve 42 and a sensor body 43. The mounting sleeve 42 is connected through the simulated wellbore 1, and the sensor body 43 is partially connected inside the mounting sleeve 42. The mounting sleeve 42 has a through hole 421 that connects the mounting sleeve 42 to the inner tubing string 11. The fork 41 of the sensor body 43 is located inside the through hole 421. With this configuration, the mounting sleeve 42 provides a stable mounting carrier for the sensor body 43, and the through hole 421 on the mounting sleeve 42 does not affect the fork 41's detection of the fluid inside the inner tubing string 11.
[0060] like Figure 1 and Figure 2 As shown, in some embodiments, the injection system 2 includes a mixing tank 21 and a screw pump. The mixing tank 21 is used to form and contain pulverized coal slurry, and the screw pump is connected between the mixing tank 21 and the annular portion 13.
[0061] In practice, coal powder and water are first added to the mixing tank 21 and mixed evenly to form a coal powder slurry. The slurry is then pumped into the annular section 13 using a screw pump. The high-speed pulverizer and standard sieve used to prepare the coal powder sample are standard laboratory equipment; therefore, the equipment and preparation steps will not be described in detail here.
[0062] With this setup, the mixing tank 21 can not only be used to stir and form pulverized coal slurry, but also to temporarily store it. Furthermore, by incorporating a screw pump, the injection rate of the pulverized coal slurry can be controlled to flexibly meet various simulated operating conditions.
[0063] like Figure 1 and Figure 2 As shown, in some embodiments, the gas injection system 3 includes a gas storage device 31 and an air compressor. The gas storage device 31 is used to contain simulated gas, and the air compressor is connected between the gas storage device 31 and the annular portion 13. That is, simulated gas is injected into the annular portion 13 by the air compressor, which can achieve gas injection quickly and controllably. The gas storage device 31 includes, but is not limited to, a gas cylinder.
[0064] Optionally, the simulated gas can be air or an inert gas such as nitrogen; no specific limitation is made here.
[0065] like Figure 5 As shown, in some embodiments, the inner tube column 11 has multiple through-holes 111 on its tube wall, and the annular portion 13 and the inner tube column 11 are interconnected through the multiple through-holes 111. The through-holes 111 have a simple structure, are easy to process, and can achieve interconnection without additional complex structures.
[0066] like Figure 3 As shown, in some embodiments, the coalbed methane wellbore coal powder migration and settling test system further includes a perforated mounting bracket 5. The mounting bracket 5 has a receiving space 51, within which the simulated wellbore 1 is at least partially located. A rotating shaft 14 is fixedly connected to the outer circumferential surface at the center of the simulated wellbore 1. The rotating shaft 14 is rotatably connected to the mounting bracket 5 and can rotate relative to the mounting bracket 5 around its own axis, thereby causing the simulated wellbore 1 to rotate and tilt. Exemplarily, a motor can be provided to drive the rotation of the rotating shaft 14, and the rotating shaft 14 can be controlled to remain relatively fixed after rotation.
[0067] With this setup, the mounting bracket 5 can provide stable support for the simulated wellbore 1, and the tilt angle of the simulated wellbore 1 can be precisely controlled through the rotating shaft 14 to adapt to different test conditions.
[0068] It should be noted that the structure and dimensions of the mounting bracket 5 are designed so as not to affect the rotation of the simulated well barrel 1, that is, the simulated well barrel 1 will not collide with the mounting bracket 5 when it rotates.
[0069] In some embodiments, two rotating shafts 14 are provided, with their central axes collinear and perpendicular to the central axis of the simulated wellbore 1. This arrangement allows the two rotating shafts 14 to balance the forces on the simulated wellbore 1, which helps improve the stability of the simulated wellbore 1 during rotation and testing.
[0070] In some embodiments, the walls of both the inner tubing 11 and the outer tubing 12 are made of transparent material.
[0071] This setup allows users to visually observe the migration and settling of coal dust inside the simulated wellbore 1, thus enabling visualization of the simulation test process.
[0072] Optionally, the walls of the inner tube column 11 and the outer tube column 12 may be made of transparent acrylic material, including but not limited to.
[0073] like Figure 1 and Figure 2 As shown, in some embodiments, the coalbed methane wellbore coal powder migration and settling test system further includes a camera device 6, which is disposed outside the mounting bracket 5 and is used to acquire images of coal powder inside the simulated wellbore 1.
[0074] By setting up camera device 6 to take pictures, images of coal powder inside the simulated well shaft 1 can be obtained, enabling image analysis of the migration and settling process of coal powder. Furthermore, image analysis technology can be used to achieve quantitative analysis of coal powder concentration and particle size.
[0075] like Figure 1 and Figure 2 As shown, in some embodiments, the camera device 6 includes a guide rail 61 and a camera 62. The guide rail 61 is spaced apart from the mounting bracket 5 and extends vertically. The camera 62 is movably connected to the guide rail 61.
[0076] With this setup, the camera 62 can move up and down along the guide rail 61, and can acquire real-time photos of coal dust at different locations in the simulated wellbore 1.
[0077] Optionally, the camera 62 can be slidably connected to the guide rail 61 or rolledly connected to the guide rail 61; this application does not make any specific limitation.
[0078] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.
Claims
1. A coalbed methane wellbore coal dust migration and settling test system, characterized by, include: The simulated wellbore (1) includes an inner tubing string (11) and an outer tubing string (12). There is an annular space (13) between the inner tubing string (11) and the outer tubing string (12), and the annular space (13) is interconnected with the inner tubing string (11). The simulated wellbore (1) can rotate and tilt around its own center within a preset angle. The injection system (2) is connected to the first end (131) of the annular portion (13), and the injection system (2) is used to inject coal powder slurry into the annular portion (13); The gas injection system (3) is connected to the second end (132) of the annular section (13). The gas injection system (3) is used to input simulated gas into the annular section (13). The second end (132) and the first end (131) are located at opposite ends of the annular section (13) along its own length. The simulated gas and the coal slurry can both flow from the annular section (13) to the inner tubular column (11) and return to the liquid injection system (2). A tuning fork resonant sensor (4) is installed in the simulated wellbore (1). The fork body (41) of the tuning fork resonant sensor (4) is located inside the inner tubing (11). The fork body (41) is used to detect the vibration frequency of the coal slurry and the simulated gas when they flow inside the inner tubing (11).
2. The coalbed methane wellbore coal powder migration and settling test system according to claim 1, characterized in that, The coalbed methane well shaft coal powder migration and settling test system also includes a hollow mounting bracket (5), the mounting bracket (5) has a receiving space (51), the simulated well shaft (1) is at least partially located in the receiving space (51), and a rotating shaft (14) is fixedly connected to the outer peripheral surface at the center of the simulated well shaft (1). The rotating shaft (14) is rotatably connected to the mounting bracket (5), and the rotating shaft (14) can rotate relative to the mounting bracket (5) around its own axis.
3. The coalbed methane wellbore pulverized coal migration and settling test system according to claim 2, characterized in that, There are two rotating shafts (14), and the central axes of the two rotating shafts (14) are collinear and perpendicular to the central axis of the simulated wellbore (1).
4. The coalbed methane wellbore coal powder migration and settling test system according to claim 2, characterized in that, The walls of both the inner tube column (11) and the outer tube column (12) are made of transparent material.
5. The coalbed methane wellbore pulverized coal migration and settling test system according to claim 4, characterized in that, The coalbed methane wellbore coal powder migration and settlement test system also includes a camera device (6), which is located on the outside of the mounting bracket (5) and is used to acquire coal powder images inside the simulated wellbore (1).
6. The coalbed methane wellbore pulverized coal migration and settling test system according to claim 5, characterized in that, The camera device (6) includes a guide rail (61) and a camera (62). The guide rail (61) is spaced apart from the mounting bracket (5) and extends vertically. The camera (62) is movably connected to the guide rail (61).
7. The coalbed methane wellbore pulverized coal migration and settling test system according to any one of claims 1 to 6, characterized in that, The injection system (2) includes a mixing tank (21) and a screw pump. The mixing tank (21) is used to form and contain the coal powder slurry, and the screw pump is connected between the mixing tank (21) and the annulus (13).
8. The coalbed methane wellbore coal powder migration and settling test system according to any one of claims 1 to 6, characterized in that, The gas injection system (3) includes a gas storage device (31) and an air compressor. The gas storage device (31) is used to contain the simulated gas, and the air compressor is connected between the gas storage device (31) and the annular section (13).
9. The coalbed methane wellbore coal powder migration and settling test system according to any one of claims 1 to 6, characterized in that, The inner tube column (11) has multiple through-holes (111) on its tube wall, and the annular portion (13) and the inner tube column (11) are interconnected through the multiple through-holes (111).
10. The coalbed methane wellbore coal powder migration and settling test system according to any one of claims 1 to 6, characterized in that, The tuning fork resonant sensor (4) includes a mounting sleeve (42) and a sensor body (43). The mounting sleeve (42) is connected through the simulated wellbore (1). The sensor body (43) is partially connected inside the mounting sleeve (42). The mounting sleeve (42) has a through hole (421) that connects the mounting sleeve (42) to the inner tubing string (11). The fork body (41) of the sensor body (43) is located inside the through hole (421).