A drilling cuttings gas desorption index determination while drilling sampling device and method

Abstract

The present application belongs to the technical field of coal mine safety, and relates to a drilling cuttings gas desorption index determination while-drilling sampling device and method, which comprises a drill rod and a drill bit connected to the front end of the drill rod, and further comprises an ejector device, a filter assembly, a sealing device, a coal sample collecting assembly and a sampling cylinder. The present application can perform drilling sampling of coal samples in a specified coal seam, prevent other coal samples in each layer from entering the sampling device before sampling, and timely remove the coal samples in the sampling device after sampling, so as to ensure that the sampled coal samples are in the target coal seam when entering the next sampling cycle. Moreover, the present application is provided with a sampling cavity for determining the drilling cuttings gas desorption index while drilling of the coal samples, so as to directly determine the drilling cuttings gas desorption index while drilling of the coal samples. The present application solves the problems of long exposure time of the coal samples and mixed sampling of coal samples at different depths in the coal samples obtained by the existing sampling technology, and improves the accuracy of the drilling cuttings gas desorption index determination.

Description

Technical Field

[0001] This invention belongs to the field of coal mine safety technology and relates to a drilling cuttings gas desorption index determination and sampling device and method. Background Technology

[0002] As the geological conditions in coal mines become increasingly complex, unfavorable factors such as floor bulging, roof subsidence, and localized gas accumulation make coal and gas outbursts highly likely to occur. Drill cuttings gas desorption index is an important indicator for predicting coal and gas outbursts.

[0003] Current sampling techniques suffer from problems such as long exposure times and mixing of coal samples from different depths, which affect the accuracy of measuring gas desorption in drill cuttings. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a drilling cuttings gas desorption index determination sampling device and method to solve the problem of coal sample mixing at different depths in existing sampling technologies.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A drilling cuttings gas desorption index determination and sampling device includes a drill rod and a drill bit connected to the front end of the drill rod, and also includes an ejector device, a filter assembly, a sealing device, a coal sample collection assembly, and a sampling cylinder. The ejector device is fitted inside the drill rod and has a guide cavity and an inner tube connected in sequence. One end of the guide cavity is connected to the hollow channel of the drill bit, and the other end is connected to the front end of the inner tube. The inner tube is provided with an ejector device air guide hole and a first coal sample collection hole. The drill rod is provided with a drill rod air guide hole that communicates with the ejector device air guide hole, and a compressed air pipe is connected to the tail end of the drill rod. The guide cavity is also provided with an ejector hole that communicates with the internal channel of the drill rod. The sealing device includes a sealing plug, which is installed at the rear end of the inner tube and is movable along the axial direction of the drill rod.

[0007] The filter assembly is disposed in the inner tube and has a conical filter screen and a circular filter screen connected in sequence from front to back. The diameter of the large diameter end of the conical filter screen matches the inner diameter of the inner tube, the outer diameter of the circular filter screen matches the inner diameter of the inner tube, the inner diameter of the circular filter screen matches the diameter of the small diameter end of the conical filter screen, and the mesh size of the conical filter screen is larger than that of the circular filter screen.

[0008] The air guide hole of the ejector device is located on the side of the circular filter screen away from the conical filter screen and at the front end of the sealing plug; the first coal sample collection hole is located between the conical filter screen and the circular filter screen.

[0009] The coal sample collection assembly has an airflow channel and a coal sample collection chamber. An air inlet is provided at the front end of the airflow channel. The coal sample collection chamber is connected to the rear end of the airflow channel. The airflow channel is installed in the inner tube. A second coal sample collection hole is provided on the airflow channel, which is connected to the first coal sample collection hole. An air outlet is provided on the side of the coal sample collection chamber near the ejector device, which is connected to the inner cavity of the drill rod. A coal sample filter screen that can move along the drill rod axis is provided at the air outlet. The mesh size of the coal sample filter screen is the same as that of the annular filter screen.

[0010] The coal sample collection chamber is provided with a piston hole on the side away from the ejector device. The sampling cylinder is slidably connected to the piston hole, and a sampling chamber is provided in the middle of the sampling cylinder. The sampling cylinder can move along the drill rod axis.

[0011] Furthermore, the air guide hole of the ejector device is connected to the air guide hole of the drill rod through an air guide pipe, and the air guide pipe is evenly arranged in the circumferential direction of the drill rod.

[0012] Furthermore, the sealing device also includes a third power source for driving movement along the drill rod axis, the coal sample filter screen is driven to move along the drill rod axis by a second power source, and the sampling cylinder is driven to move along the drill rod axis by a first power source.

[0013] Furthermore, the first power source, the second power source, and the third power source are all linear motors.

[0014] Furthermore, the cone-shaped filter screen has a mesh size of 3mm, while the coal sample filter screen and the circular filter screen have a mesh size of 1mm.

[0015] Furthermore, the outer diameter of the sampling cylinder located on both sides of the sampling chamber matches the inner diameter of the piston hole to form a sealed connection.

[0016] A method for sampling while drilling to determine the desorption index of drill cuttings gas, comprising the above-mentioned sampling device for measuring the desorption index of drill cuttings gas, specifically including the following steps:

[0017] a. During normal drilling, the sealing plug is moved backward along the drill rod axis to remove the inner tube, so that the compressed air in the drill rod can directly enter the inner tube from the tail end and be blown out through the drill bit to prevent drill cuttings from entering the inner tube through the drill bit.

[0018] b. When drilling into the target coal seam, the sealing plug is moved forward along the drill rod axis to enter the inner tube, sealing the tail end of the inner tube, so that the compressed air in the drill rod enters the guide cavity from the ejector hole and enters the airflow channel from the air inlet.

[0019] c. Compressed air entering the guide cavity enters the air guide hole of the ejector device through the inner tube, and then leaves the drill rod through the air guide pipe and the drill rod air guide hole, forming a negative pressure in the ejector device. Under the action of negative pressure, the ejector device draws the crushed coal sample into the inner tube. After being screened by the filter component, the coal sample enters the first coal sample collection hole and enters the airflow channel through the second coal sample collection hole.

[0020] d. Move the coal sample filter screen backward along the drill rod axis to seal the air outlet. The compressed air entering the airflow channel from the air inlet blows the coal sample, causing the coal sample to enter the coal sample collection chamber through the airflow channel. Under the sealing effect of the coal sample filter screen, the coal sample accumulates in the coal sample collection chamber.

[0021] e. Move the sampling tube forward along the drill rod axis so that the sampling chamber on the sampling tube is inserted into the coal sample collection chamber, thereby allowing some of the coal sample accumulated in the coal sample collection chamber to enter the sampling chamber. Then move the sampling tube backward along the drill rod axis so that the sampling chamber is inserted into or removed from the coal sample collection chamber, and the sampling is completed.

[0022] Furthermore, it also includes step f;

[0023] f. Once sampling is complete, move the coal sample filter screen forward along the drill rod axis to open the air outlet, move the sealing plug backward along the drill rod axis to exit the inner tube, and use the compressed air entering the airflow channel through the air inlet to discharge the coal sample in the coal sample collection chamber through the air outlet. Then, discharge the coal sample directly from the drill rod through the ejector device and drill bit to ensure that the coal sample taken is from the target coal seam when entering the next sampling cycle.

[0024] The beneficial effects of this invention are as follows:

[0025] This invention provides a drilling cuttings gas desorption index determination sampling device and method, which can perform drilling sampling of coal samples from a specified coal seam. This prevents coal samples from other seams from entering the sampling device before sampling, and promptly removes coal samples from the sampling device after sampling to ensure that the sampled coal is from the target coal seam when entering the next sampling cycle. Furthermore, it includes a sampling chamber for drilling cuttings gas desorption index determination, allowing for direct measurement of the desorption index. This solves the problems of long coal sample exposure time and mixing of coal samples from different depths encountered with existing sampling techniques, thus improving the accuracy of drilling cuttings gas desorption index determination.

[0026] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0027] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0028] Figure 1 This is a schematic cross-sectional view of a drilling cuttings gas desorption index measurement sampling device in the embodiment;

[0029] Figure 2 This is an explosion diagram of a drilling cuttings gas desorption index measurement sampling device in the embodiment;

[0030] Figure 3 This is a schematic diagram of the drill pipe structure;

[0031] Figure 4 This is a schematic diagram of the ejector device.

[0032] Figure 5 This is a schematic diagram of the filter assembly.

[0033] Figure 6 This is a schematic diagram of the coal sample collection assembly.

[0034] Figure 7 This is a schematic diagram of the sampling cylinder.

[0035] Reference numerals: Drill rod 1, Drill rod air guide hole 11, Ejector device 2, Ejector hole 21, Guide cavity 22, Inner tube 23, Ejector device air guide hole 231, First coal sample collection hole 232, Sealing plug 24, Air guide tube 25, Drill bit 3, Filter assembly 4, Conical filter screen 41, Circular filter screen 42, Coal sample collection assembly 5, Air inlet 51, Airflow channel 52, Second coal sample collection hole 521, Coal sample collection cavity 53, Air outlet 531, Coal sample filter screen 532, Piston hole 533, Sampling cavity 54, Sampling cylinder 6, Sampling chamber 61, Sealing device 7, Power source 8, First power source 81, Second power source 82, Third power source 83. Detailed Implementation

[0036] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0037] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0038] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and 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, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0039] Please see Figures 1 to 7 This is a drilling cuttings gas desorption index determination and sampling device, which includes a drill pipe 1, an ejector device 2, a drill bit 3, a filter assembly 4, a coal sample collection assembly 5, a sampling tube 6, a sealing device 7, and a power source 8.

[0040] The drill rod 1 is a hollow drill rod, the drill bit 3 is installed at the front end of the drill rod 1 and has a hollow channel, the tail end of the drill rod 1 is connected to a compressed air pipe, and the drill rod 1 is provided with a drill rod air guide hole 11.

[0041] The ejector device 2 is fitted inside the drill rod 1, and one end is connected to the hollow channel of the drill bit 3. The ejector device 2 has a guide cavity 22 and an inner tube 23 connected in sequence. One end of the guide cavity 22 is connected to the hollow channel of the drill bit 3, and the other end is connected to the inner tube 23. The inner tube 23 is provided with an ejector device air guide hole 231 and a first coal sample collection hole 232. The ejector device air guide hole 231 is connected to the drill rod air guide hole 11 through an air guide pipe 25. The air guide pipe 25 has a circumferentially evenly distributed structure inside the drill rod 1. The guide cavity 22 is also provided with an ejector hole 21 that connects to the internal channel of the drill rod 1 to introduce the compressed air in the drill rod 1 into the ejector device 2.

[0042] The sealing device 7 includes a sealing plug 24 and a third power source 83. The sealing plug 24 is installed at the rear end of the inner tube 23, and the third power source 83 is installed at the rear end of the sealing plug 24 to drive the movement along the axial direction of the drill pipe 1.

[0043] The filter assembly 4 has a conical filter screen 41 and a circular filter screen 42. Both the conical filter screen 41 and the circular filter screen 42 are installed in the inner tube 23. The circular filter screen 42 is installed at the rear end of the conical filter screen 41. The diameter of the large diameter end of the conical filter screen 41 matches the inner diameter of the inner tube 23. The outer diameter of the circular filter screen 42 matches the inner diameter of the inner tube 23. The inner diameter of the circular filter screen 42 matches the diameter of the small diameter end of the conical filter screen 41. The large diameter end of the conical filter screen 41 and / or the circular filter screen 42 are connected to the inner wall of the inner tube 23 to fix the filter assembly 4.

[0044] The air guide hole 231 of the ejector device is located on the side of the circular filter screen 42 away from the conical filter screen 41 and at the front end of the sealing plug 24. The first coal sample collection hole 232 is located between the conical filter screen 41 and the circular filter screen 42, so that only the coal sample that has passed through the conical filter screen 41 can enter the first coal sample collection hole 232.

[0045] The coal sample collection assembly 5 has an air inlet 51, an airflow channel 52, a coal sample collection chamber 53, and a sampling chamber 54. The air inlet 51 is located at the front end of the airflow channel 52, and the coal sample collection chamber 53 is connected to the rear end of the airflow channel 52. The airflow channel 52 is installed on the outside of the inner tube 23 and fits against the outer circle of the inner tube 23. The airflow channel 52 is provided with a second coal sample collection hole 521 that communicates with the first coal sample collection hole 232, so that the coal sample enters the airflow channel 52 from the ejector device 2.

[0046] The coal sample collection chamber 53 is provided with an air outlet 231 that connects to the inner cavity of the drill rod 1 on the side near the ejector device 2. A coal sample filter screen 532 is provided at the air outlet 231, and a second power source 82 for driving the coal sample filter screen 532 to move along the axial direction of the drill rod 1 is provided on the coal sample filter screen 532.

[0047] The coal sample collection chamber 53 is provided with a piston hole 533 communicating with the sampling chamber 54 on the side away from the ejector device 2. The sampling cylinder 6 is located in the coal sample collection assembly 5 and is slidably connected with the piston hole 533. The sampling cylinder 6 is provided with a sampling chamber 61 in the middle, and the outer diameter of the sampling cylinder 6 located on both sides of the sampling chamber 61 matches the inner diameter of the piston hole 533 to form a sealed connection. At the tail end of the sampling cylinder 6 (the end away from the coal sample collection chamber 53), a first power source 81 is provided for driving it to move along the axial direction of the drill rod 1.

[0048] Preferably, axial retaining rings and sealing rings are provided on the outer circles of the sampling cylinder 6 located on both sides of the sampling chamber 61 to achieve axial positioning and better sealing performance.

[0049] The mesh size of the conical filter 41 is larger than that of the coal sample filter 532 and the circular filter 42. Preferably, the mesh size of the conical filter 41 is 3mm, and the mesh size of the coal sample filter 532 and the circular filter 42 is 1mm, so that some coal samples of 1-3mm can enter the first coal sample collection hole 232 under the joint filtration of the conical filter 41 and the circular filter 42.

[0050] The first power source 81, the second power source 82, and the third power source 83 constitute the power source 8 of the device. Specifically, the first power source 81, the second power source 82, and the third power source 83 can be configured as linear motors or other drive devices capable of providing linear motion. The present invention can achieve drilling sampling by controlling the air intake of the power source 8 and the compressed air pipeline at the tail end of the drill rod, and ensure that the coal sample taken is the target coal seam.

[0051] The specific steps of the sampling method for determining the gas desorption index of drill cuttings using the above-mentioned drilling sampling device are as follows:

[0052] During normal drilling, the sealing plug 24 is driven out of the inner tube 23 by the third power source 83, so that the compressed air in the drill rod 1 can directly enter the inner tube 23 from the tail end of the inner tube 23 and then enter the drill bit 3, preventing drill cuttings from entering the device through the drill bit 3.

[0053] When drilling into the target coal seam, the sealing plug 24 is driven by the third power source 83 to enter the inner tube 23 and seal the tail end of the inner tube 23, so that the compressed air in the drill rod 1 enters the guide cavity 22 from the ejector hole 21 and enters the airflow channel 52 from the air inlet 51.

[0054] The compressed air entering the guide cavity 22 mainly enters the air guide hole 231 of the ejector device, and then leaves the drill rod through the air guide pipe 25 and the drill rod air guide hole 11. It forms a negative pressure in the ejector device 2 and part of it enters the first coal sample collection hole 232. Under the action of negative pressure, the ejector device 2 draws the broken coal sample into the inner tube 23. The coal sample is screened by the filter component 4. The 1-3mm coal sample enters the first coal sample collection hole 232 and enters the airflow channel 52 through the second coal sample collection hole 521.

[0055] Driven by the second power source 82, the coal sample filter screen 532 seals the air outlet 531. Compressed air entering the airflow channel 52 from the air inlet 51 blows the coal sample, causing the coal sample to enter the coal sample collection chamber 53 through the airflow channel 52. Under the sealing effect of the coal sample filter screen 532, 1-3mm coal samples accumulate in the coal sample collection chamber 53.

[0056] Driven by the first power source 81, the sampling cylinder 6 enters the coal sample collection chamber 53 at the location of the sampling chamber 61, allowing a certain mass of coal sample to enter the sampling chamber 61. Driven by the first power source 81, the sampling cylinder 6 then enters the sampling chamber 54 at the location of the sampling chamber 61, completing the sampling process. Specifically, the drill cuttings gas desorption index can be directly measured while drilling in the sampling chamber 54.

[0057] Preferably, after sampling and measurement are completed, the sampling cylinder 6, driven by the first power source 81, enters the coal sample collection chamber 53 where the sampling chamber 61 is located. Driven by the second power source 82, the coal sample filter 532 leaves the air outlet 531. The third power source 83 drives the sealing plug 24 to exit the inner tube 23, and the compressed air entering the airflow channel 52 through the air inlet 51 discharges the coal sample in the coal sample collection chamber 53 and the sampling chamber 61 through the air outlet 531. Then, the drill rod 1 is directly discharged through the ejector device 2 and the drill bit 3. Then, driven by the first power source 81, the sampling cylinder 6 enters the sampling chamber 54 where the sampling chamber 61 is located, so as to ensure that the coal sample taken is the target coal seam when entering the next sampling cycle.

[0058] This invention enables drilling sampling of coal samples from designated coal seams, solving the problem of long coal sample exposure time. It also prevents coal samples from other coal seams from entering the sampling device before sampling and promptly removes coal samples from the device after sampling, ensuring that the sampled coal is from the target coal seam before entering the next sampling cycle. Furthermore, it includes a sampling chamber 54 for drilling cuttings gas desorption index measurement, allowing for direct measurement of drilling cuttings gas desorption index. This solves the problems of long coal sample exposure time and mixing of coal samples from different depths encountered with existing sampling techniques, improving the accuracy of drilling cuttings gas desorption index measurement.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A drilling cuttings gas desorption index determination and sampling device, comprising a drill pipe and a drill bit connected to the front end of the drill pipe, characterized in that: It also includes an ejector device, a filter assembly, a sealing device, a coal sample collection assembly, and a sampling tube. The ejector device is fitted inside the drill rod. The ejector device has a guide cavity and an inner tube connected in sequence. One end of the guide cavity is connected to the hollow channel of the drill bit, and the other end is connected to the front end of the inner tube. The inner tube is provided with an ejector device air guide hole and a first coal sample collection hole. The drill rod is provided with a drill rod air guide hole that communicates with the ejector device air guide hole. A compressed air pipe is connected to the tail end of the drill rod. The guide cavity is also provided with an ejector hole that communicates with the internal channel of the drill rod. The sealing device includes a sealing plug. The sealing plug is installed at the rear end of the inner tube and can move along the axial direction of the drill rod. The filter assembly is disposed in the inner tube and has a conical filter screen and a circular filter screen connected in sequence from front to back. The diameter of the large diameter end of the conical filter screen matches the inner diameter of the inner tube, the outer diameter of the circular filter screen matches the inner diameter of the inner tube, the inner diameter of the circular filter screen matches the diameter of the small diameter end of the conical filter screen, and the mesh size of the conical filter screen is larger than that of the circular filter screen. The air guide hole of the ejector device is located on the side of the circular filter screen away from the conical filter screen and at the front end of the sealing plug; the first coal sample collection hole is located between the conical filter screen and the circular filter screen. The coal sample collection assembly has an airflow channel and a coal sample collection chamber. An air inlet is provided at the front end of the airflow channel. The coal sample collection chamber is connected to the rear end of the airflow channel. The airflow channel is installed in the inner tube. A second coal sample collection hole is provided on the airflow channel, which is connected to the first coal sample collection hole. An air outlet is provided on the side of the coal sample collection chamber near the ejector device, which is connected to the inner cavity of the drill rod. A coal sample filter screen that can move along the drill rod axis is provided at the air outlet. The mesh size of the coal sample filter screen is the same as that of the annular filter screen. The coal sample collection chamber is provided with a piston hole on the side away from the ejector device. The sampling cylinder is slidably connected to the piston hole, and a sampling chamber is provided in the middle of the sampling cylinder. The sampling cylinder can move along the drill rod axis.

2. The drilling cuttings gas desorption index determination and sampling device according to claim 1, characterized in that: The air guide hole of the ejector device is connected to the air guide hole of the drill rod through an air guide pipe, which is evenly arranged in the circumferential direction of the drill rod.

3. The drilling cuttings gas desorption index determination and sampling device according to claim 1, characterized in that: The sealing device also includes a third power source for driving the movement along the drill rod axis. The coal sample filter screen is driven to move along the drill rod axis by a second power source, and the sampling cylinder is driven to move along the drill rod axis by a first power source.

4. The drilling cuttings gas desorption index determination and sampling device according to claim 3, characterized in that: The first power source, the second power source, and the third power source are all linear motors.

5. The drilling cuttings gas desorption index determination and sampling device according to claim 1, characterized in that: The cone-shaped filter screen has a mesh size of 3mm, while the coal sample filter screen and the circular filter screen have a mesh size of 1mm.

6. The drilling cuttings gas desorption index determination and sampling device according to claim 1, characterized in that: The outer diameter of the sampling cylinder located on both sides of the sampling chamber matches the inner diameter of the piston hole to form a sealed connection.

7. A method for determining the gas desorption index of drill cuttings through sampling while drilling, characterized in that, The drilling cuttings gas desorption index determination sampling device according to claim 2 specifically includes the following steps: a. During normal drilling, the sealing plug is moved backward along the drill rod axis to remove the inner tube, so that the compressed air in the drill rod can directly enter the inner tube from the tail end and be blown out through the drill bit to prevent drill cuttings from entering the inner tube through the drill bit. b. When drilling into the target coal seam, the sealing plug is moved forward along the drill rod axis to enter the inner tube, sealing the tail end of the inner tube, so that the compressed air in the drill rod enters the guide cavity from the ejector hole and enters the airflow channel from the air inlet. c. Compressed air entering the guide cavity enters the air guide hole of the ejector device through the inner tube, and then leaves the drill rod through the air guide pipe and the drill rod air guide hole, forming a negative pressure in the ejector device. Under the action of negative pressure, the ejector device draws the crushed coal sample into the inner tube. After being screened by the filter component, the coal sample enters the first coal sample collection hole and enters the airflow channel through the second coal sample collection hole. d. Move the coal sample filter screen backward along the drill rod axis to seal the air outlet. The compressed air entering the airflow channel from the air inlet blows the coal sample, causing the coal sample to enter the coal sample collection chamber through the airflow channel. Under the sealing effect of the coal sample filter screen, the coal sample accumulates in the coal sample collection chamber. e. Move the sampling tube forward along the drill rod axis so that the sampling chamber on the sampling tube is inserted into the coal sample collection chamber, thereby allowing some of the coal sample accumulated in the coal sample collection chamber to enter the sampling chamber. Then move the sampling tube backward along the drill rod axis so that the sampling chamber is inserted into or removed from the coal sample collection chamber, and the sampling is completed.

8. The method for determining the gas desorption index of drill cuttings and sampling while drilling according to claim 7, characterized in that: It also includes step f; f. Once sampling is complete, move the coal sample filter screen forward along the drill rod axis to open the air outlet, move the sealing plug backward along the drill rod axis to exit the inner tube, and use the compressed air entering the airflow channel through the air inlet to discharge the coal sample in the coal sample collection chamber through the air outlet. Then, discharge the coal sample directly from the drill rod through the ejector device and drill bit to ensure that the coal sample taken is from the target coal seam when entering the next sampling cycle.

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