A gas sampling device and method in near-surface formations

Abstract

This invention discloses a gas sampling device and method for near-surface rock formations, comprising: a drill frame with an annular drill tube fitted on its exterior, the annular drill tube being connected to the drill frame via a hydraulic cylinder; a rotating seat rotatably mounted on the upper part of the drill frame, with a hydraulic cylinder fixed at its center, the lower output end of the hydraulic cylinder being connected to a drill rod, and the lower part of the drill rod being provided with vertically distributed fixing devices and a water jet cutting device; a power mechanism for regulating the operation of the rotating seat being mounted on the drill frame; and a weighing sensor fixedly mounted on the lower part of the drill frame, with a sampling annular tube at its upper end, and vertically distributed gas collection devices and solid material collection devices on the sampling annular tube.

Description

Technical Field

[0001] This invention relates to the field of gas sampling technology in near-surface rock formations, specifically to a gas sampling device and method in near-surface rock formations. Background Technology

[0002] Gas sampling from near-surface rock strata is a crucial task in geological exploration and environmental monitoring. These gas samples help determine whether surface rock strata containing organic matter contain gas and further analyze the source of the gas, specifically whether it originates from the rock strata. Furthermore, determining the composition and content of gases is of significant value in assessing greenhouse gas emissions and environmental pollution risks. However, traditional gas sampling methods have many limitations, such as low sampling efficiency, poor sample representativeness, complex operation, and the inability to measure gas content simultaneously with sampling.

[0003] Currently, existing near-surface rock gas sampling technologies mainly suffer from the following problems:

[0004] Firstly, the separation of sampling and measurement leads to low efficiency. Traditional methods typically involve manual sampling or obtaining rock gas using simple drilling tools. Samples must then be transported to a laboratory for testing, which is not only time-consuming but also prone to compositional changes or contamination during transportation and storage, resulting in distorted measurement results. Although some field sampling devices integrate gas sensors, they cannot simultaneously acquire the mass of the rock sample, making it difficult to establish a quantitative relationship between gas content and unit mass of the rock layer.

[0005] Secondly, the samples lack representativeness, making accurate quantification difficult. Existing technologies mostly use overall gas extraction or adsorption methods to collect gas, which cannot clearly define the correspondence between gas and specific rock strata. When drilling reaches the target depth, due to the lack of effective stratum isolation methods, gases from different depths are prone to cross-layer mixing, making the collected gas samples unable to accurately reflect the gas composition of the target rock strata. At the same time, traditional sampling methods cannot obtain rock samples from the same location and depth, resulting in a lack of direct evidence for determining the gas source (autogenous or deep seepage).

[0006] Therefore, it is necessary to provide a gas sampling device and method in near-surface rock strata to solve the problems mentioned in the background art. Summary of the Invention

[0007] To achieve the above objectives, the present invention provides the following technical solution: a gas sampling device for near-surface rock strata, comprising:

[0008] The drill barrel frame is fitted with an annular drill barrel, which is connected to the drill barrel frame via a hydraulic cylinder.

[0009] The rotating seat is rotatably installed inside the upper part of the drill barrel frame. A hydraulic cylinder is fixed at its center. The lower output end of the hydraulic cylinder is connected to the drill rod. The lower part of the drill rod is equipped with a fixing device and a water jet cutting device distributed vertically. The drill barrel frame is equipped with a power mechanism for regulating the operation of the rotating seat.

[0010] The weighing sensor is fixedly installed inside the lower part of the drill barrel frame, and a sampling ring is provided at its upper end. The sampling ring is equipped with gas collection devices and solid material collection devices distributed vertically.

[0011] Preferably, the drill pipe includes:

[0012] The long rod section has a limiting sliding cavity at its lower end;

[0013] The drill bit has a limiting slider at its upper end that is slidably connected to the limiting slide cavity, and the drill bit is also connected to the long rod part by a spring.

[0014] Preferably, the waterjet cutting device includes:

[0015] The supply device is located on the upper part of the long pole;

[0016] The main flow pipe is located inside the long rod section, with its upper end connected to the supply device and its lower end connected to the branch pipe.

[0017] The jet channel is located on the drill bit, with its outlet pointing horizontally. The branch pipe is slidably connected to the jet channel inlet. When the limiting slider is located at the upper end of the limiting slide cavity, the jet channel outlet is located inside the lower end of the long rod. When the limiting slider is located at the lower end of the limiting slide cavity, the jet channel outlet is located outside the lower end of the long rod.

[0018] Preferably, the fixing device includes:

[0019] A rubber ring is fitted over the outer wall of the long rod.

[0020] The hydraulic chamber is located inside the long rod section. Its lower end is connected to the rubber ring bladder, and its upper end is equipped with a hydraulic cylinder three. The lower output end of the hydraulic cylinder three is equipped with a hydraulic plug.

[0021] Preferably, the solid material collection device includes:

[0022] The annular cavity is located inside the wall of the sampling ring cylinder, with an annular opening at the upper part of its inner wall and a stirring assembly at the bottom.

[0023] The ring cover is coaxially fitted around the outside of the drill rod and located on the inner wall of the sampling ring cylinder above the ring opening. A grinding disc rotates at its lower end.

[0024] The second power mechanism, located in the ring cover, is used to regulate the movement of the grinding disc;

[0025] A sealing assembly is located on the inner wall of the sampling ring cylinder below the ring opening.

[0026] Preferably, the grinding disc includes a carrier ring rotatably connected to the lower end of the ring cover, and an abrasive scraper corresponding to the ring opening is provided on the lower circumference of the ring.

[0027] Preferably, the sealing assembly includes:

[0028] Multiple thin plates are arranged circumferentially on the inner wall of the sampling ring cylinder;

[0029] An arc plate is placed between adjacent thin plates, and its exterior is fitted with a rolling arc-shaped sleeve.

[0030] Preferably, the stirring assembly includes:

[0031] Hydraulic cylinder four is located at the bottom of the annular cavity, and its upper end is provided with a bottom ring located in the annular cavity. The bottom ring is provided with a rotatable rotating ring one and a power mechanism three for regulating the movement of the rotating ring one. A magnetic column one is also provided inside the rotating ring one.

[0032] The second rotating ring rotates at the upper end of the bottom ring. Inside it is a second magnetic column that attracts the first magnetic column. Its outer wall is equipped with a scraper, and the upper end of the scraper is equipped with a stirring rod.

[0033] One arc-shaped opening is evenly distributed around the lower part of the outer wall of the annular cavity;

[0034] The second arc opening is located on the outer wall of the circumferential drill barrel and is set in correspondence with the first arc opening.

[0035] Preferably, the gas collection device includes:

[0036] A heating ring is located inside the outer wall of the ring cavity;

[0037] A vent is located at the top of the annular cavity, and a brush rod that interacts with the vent is connected to the outer end of the abrasive scraper.

[0038] The transfer chamber is located above the vent.

[0039] The gas ring chamber is located on the sampling ring cylinder. Its inlet is connected to the transfer chamber and is equipped with a valve. Its outlet is connected to a vacuum pump. A non-dispersive infrared sensor is installed at the top of the chamber.

[0040] A method for gas sampling in near-surface rock formations includes the following steps:

[0041] Step 1: When the circumferential drill barrel reaches the required sampling position, it retracts through the hydraulic cylinder and simultaneously rotates by adjusting the drill barrel frame to perform circumferential drilling for a certain length until the required length is reached, forming a cylindrical sample;

[0042] Step 2: Start the power mechanism to control the rotation of the rotating seat, and then control the drill rod through the hydraulic cylinder to drill a certain length into the center of the cylindrical sample until the required length is reached, forming a ring sample;

[0043] Step 3: Activate the water jet cutting device to horizontally cut the annular sample until the annular sample is severed;

[0044] Step 4: Activate the fixing device to fix the truncated annular sample to the drill rod;

[0045] Step 5: Adjust the drill rod to reset using hydraulic cylinder 2, and simultaneously start the solid material collection device to sample the truncated annular sample;

[0046] Step 6: Collect the gas escaping from the solid material collection device using a gas collection device.

[0047] Compared with the prior art, the present invention provides a gas sampling device and method in near-surface rock strata, which has the following beneficial effects:

[0048] This invention integrates multiple functions, including annular drilling, central drilling, water jet cutting, sample fixation, crushing and collection, and gas analysis, into a single device. Through the coordinated operation of the drill frame, annular drill barrel, drill rod, and sampling ring, the entire process of obtaining cylindrical samples, processing annular samples, horizontal cutting at the bottom, sample lifting, layer-by-layer crushing, and real-time gas detection can be completed sequentially in a single drilling operation. This eliminates the need for multiple drill lifting or equipment changes, significantly shortening on-site operation time and improving sampling efficiency. A weighing sensor is installed at the bottom of the sampling ring to monitor the overall weight change of the sampling ring in real time. By comparing the empty weight, the weight after loading the annular sample, and the weight after solid material discharge, the total mass of the collected rock sample can be accurately calculated. This mass data, combined with the total gas volume measured by the gas collection device, yields the gas release per unit mass of rock. This provides crucial quantitative evidence for evaluating the gas content of rock strata and identifying gas sources, overcoming the shortcomings of traditional methods that either provide gas without quantity or separate quantity from quality.

[0049] This invention employs a two-step processing method: first, annular drilling, then central drilling. This creates a uniformly thick annular sample within the rock strata. The inner and outer walls of the annular sample form sealed spaces with the drill rod and sampling ring, respectively. A water jet cutting device is used to smoothly separate the bottom of the annular sample from the parent rock, ensuring that the collected sample originates entirely from the target depth strata. Furthermore, during the crushing process, the inner and outer walls of the annular sample remain sealed, effectively preventing gas from different layers from entering and external air pollution. This ensures that the gas detection results accurately reflect the gas composition of the target rock strata. The solid material collection device incorporates a two-stage crushing mechanism: a grinding disc and a stirring assembly. The grinding disc grinds the upper surface of the annular sample layer by layer using an abrasive scraper, gradually crushing the sample from the outside in and from top to bottom. The solid material entering the annular cavity is further stirred and crushed by the scraper and stirring rod in the stirring assembly, refining the rock particles and increasing the specific surface area. Simultaneously, a heating ring is installed on the outer wall of the annular cavity to moderately heat the solid material, promoting the full release of adsorbed and encapsulated gases, improving the gas release rate, and ensuring the accuracy and representativeness of the test results.

[0050] In this invention, a sealing component is installed on the inner wall of the sampling ring cylinder, consisting of multiple thin plates and an arc plate between adjacent thin plates. A rollable arc-shaped sleeve is fitted outside the arc plate. When the drill rod moves the annular sample up and down, the outer wall of the annular sample contacts the arc-shaped sleeve, causing the arc-shaped sleeve to roll and achieve dynamic sealing. While ensuring the sealing effect between the outer wall of the annular sample and the inner wall of the sampling ring cylinder, the frictional resistance between the two is significantly reduced, avoiding the problem of sealing failure caused by excessive wear of the sealing components. This allows the device to maintain long-term stable sealing performance during multiple reciprocating movements. In addition, the water jet cutting device is linked with the drill rod structure: when the supply device is started, the pressure of the high-pressure water flow causes the drill bit to automatically overcome the spring force and extend downward, exposing the jet channel outlet outside the lower end of the long rod, achieving horizontal annular cutting. After the cutting is completed, the supply device stops, the spring resets, and the drill bit retracts to avoid interfering with subsequent operations. At the same time, the rubber ring of the fixing device expands hydraulically and fits tightly against the central column cavity wall of the annular sample, achieving rapid clamping and release. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0052] Figure 2 This is a schematic diagram of the mainstream tube structure of the present invention;

[0053] Figure 3 This is a schematic diagram of the fixing device structure of the present invention;

[0054] Figure 4 This is a schematic diagram of the solid material collection device of the present invention;

[0055] Figure 5This is a schematic diagram of the stirring assembly structure of the present invention;

[0056] Figure 6 This is a schematic diagram of the sealing assembly structure of the present invention;

[0057] Figure 7 This is a schematic diagram of the grinding disc structure of the present invention;

[0058] Figure 8 This is a schematic diagram of the gas collection device of the present invention;

[0059] In the diagram: 1. Drill barrel frame; 2. Hydraulic cylinder one; 3. Ring drill barrel; 4. Hydraulic cylinder two; 5. Drill rod; 6. Water jet cutting device; 7. Fixing device; 8. Solid material collection device; 9. Gas collection device; 11. Weighing sensor; 12. Sampling ring barrel; 31. Power mechanism one; 32. Rotating seat; 51. Long rod section; 52. Drill bit; 53. Spring; 511. Limiting slide cavity; 521. Limiting slider; 522. Jet channel; 61. Supply device; 62. Main stream pipe; 63. Branch pipe; 71. Rubber ring bladder; 72. Hydraulic cavity; 73. Hydraulic cylinder three; 74. Hydraulic plug; 81. Ring cavity; 82. Ring opening; 83. Ring cover; 84. 85. Grinding blade; 86. Power mechanism two; 87. Sealing assembly; 88. Stirring assembly; 89. Carrier ring; 80. Abrasive scraper; 81. Brush rod; 82. Thin plate; 83. Arc plate; 84. Arc bladder sleeve; 85. Hydraulic cylinder four; 86. Bottom ring; 87. Rotating ring one; 88. Magnetic column one; 89. Power mechanism three; 80. Rotating ring two; 81. Magnetic column two; 82. Scraper; 83. Stirring rod; 84. Arc opening one; 85. Arc opening two; 96. Heating ring; 97. Vent hole; 98. Transfer chamber; 99. Gas ring box; 90. Valve; 91. Vacuum pump; 92. Non-dispersive infrared sensor. Detailed Implementation

[0060] Reference Figures 1-8 The present invention provides a technical solution: a gas sampling device for near-surface rock strata, comprising:

[0061] Drill barrel frame 1, with an annular drill barrel 3 fitted on its outside, and the annular drill barrel 3 and the drill barrel frame 1 are connected by a hydraulic cylinder 2;

[0062] Rotary seat 32 is rotatably installed inside the upper part of the drill barrel frame 1. A hydraulic cylinder 4 is fixed at its center. The lower output end of the hydraulic cylinder 4 is connected to the drill rod 5. The lower part of the drill rod 5 is provided with a fixing device 7 and a water jet cutting device 6 distributed vertically. The drill barrel frame 1 is provided with a power mechanism 31 for regulating the operation of the rotating seat 32.

[0063] The weighing sensor 11 is fixedly installed in the lower part of the drill barrel frame 1, and a sampling ring cylinder 12 is provided at its upper end. The sampling ring cylinder 12 is provided with a gas collection device 9 and a solid material collection device 8 distributed vertically.

[0064] Reference Figure 1 As shown, by adjusting the rotation of the drill barrel frame 1, the annular drill barrel 3 can be rotated. Then, by retracting the hydraulic cylinder 2 downward, the annular drill barrel 3 can be driven to move in an annular drilling manner to form a cylindrical sample. After completing the required length of cylindrical sample, the rotation of the drill barrel frame 1 is stopped. Then, the rotation of the drill rod 5 is adjusted by the power mechanism 31, and the drill rod 5 is adjusted to drill downward by the hydraulic cylinder 4, that is, to drill again in the center of the cylindrical sample to form a cylindrical cavity of a certain length, thereby forming an annular sample. Then, the water jet cutting device 6 is started to horizontally cut the annular sample until it is cut off. Then, the cut annular sample is fixed to the outside of the drill rod 5 by the fixing device 7. Then, the drill rod 5 is reset by the hydraulic cylinder 4, and the solid material collection device 8 is used to process the annular sample from the top end until the annular sample is completely processed. Then, the gas generated in the solid material collection device 8 during the process is collected by the gas collection device 9.

[0065] The weighing sensor 11 weighs the entire sampling ring cylinder 12, and then weighs it again using the weight of the sample inside, thus obtaining the weight of the sampled sample.

[0066] In this embodiment, the drill pipe 5 includes:

[0067] The long rod portion 51 has a limiting sliding cavity 511 at its lower end;

[0068] The drill bit 52 has a limiting slider 521 at its upper end that is slidably connected to the limiting slide cavity 511, and the drill bit 52 is also connected to the long rod part 51 by a spring 53.

[0069] Reference Figure 3 As shown, in the initial state, the spring 53 is in a contracted state, so that the limiting slider 521 is located at the uppermost end of the limiting slide cavity 511. When the spring 53 is in a fully stretched state, the limiting slider 521 is located at the lowermost end of the limiting slide cavity 511. In addition, a recessed space of a certain length is formed between the upper end of the drill bit 52 and the lower end of the long rod 51, corresponding to the upper outer wall of the drill bit 52.

[0070] In this embodiment, the waterjet cutting device 6 includes:

[0071] A supply device 61 is located on the upper part of the long rod 51;

[0072] The main flow pipe 62 is located inside the long rod section, with its upper end connected to the supply device 61 and its lower end connected to the branch flow pipe 63.

[0073] The jet channel 522 is provided on the drill bit 52, and its outlet is horizontal. The branch pipe 63 is slidably connected to the inlet of the jet channel 522. When the limiting slider 521 is located at the upper end of the limiting slide cavity 511, the outlet of the jet channel 522 is located inside the lower end of the long rod 51. When the limiting slider 521 is located at the lower end of the limiting slide cavity 511, the outlet of the jet channel 522 is located outside the lower end of the long rod 51.

[0074] Combination Figure 2 , Figure 3 As shown, the branch pipe 63 and the jet channel 522 are arranged correspondingly and are evenly arranged in a circle to improve cutting efficiency. The lower end of the branch pipe 63 extends into the upper end of the jet channel 522. It should be noted that when the supply device 61 is started, the spring 53 will be in a fully stretched state due to the pressure. At this time, the length of the branch pipe 63 exposed in the jet channel 522 is increased, and the branch pipe 63 and the jet channel 522 are still in a connected state.

[0075] In addition, when the limiting slider 521 is located at the lower end of the limiting slide cavity 511, the outlet of the jet channel 522 is located outside the lower end of the long rod portion 51 and in the recessed space area.

[0076] In this embodiment, the fixing device 7 includes:

[0077] A rubber ring 71 is fitted onto the outer wall of the long rod 51;

[0078] Hydraulic chamber 72 is located inside the long rod section. Its lower end is connected to rubber ring 71. Hydraulic cylinder 73 is provided at its upper end. Hydraulic plug 74 is provided at the lower output end of hydraulic cylinder 73.

[0079] The outer wall of the long rod 51 is provided with an annular groove to accommodate the rubber ring 71. When the rubber ring 71 is in a contracted state, it can be stored in the annular groove. Specifically, when the hydraulic cylinder 73 adjusts the hydraulic plug 74 to move downward, the rubber ring 71 expands outward, so that the rubber ring 71 can be in close contact with the central column cavity wall of the annular sample and be fixed by friction.

[0080] In this embodiment, the solid material collection device 8 includes:

[0081] An annular cavity 81 is located inside the wall of the sampling ring cylinder 12, with an annular opening 82 on the upper part of its inner wall and a stirring assembly 87 at its bottom.

[0082] The ring cover 83 is coaxially sleeved on the outside of the drill rod 5 and located on the inner wall of the sampling ring cylinder 12 above the ring opening 82. A grinding disc 84 rotates at its lower end.

[0083] The second power mechanism 85 is located in the ring cover 83 and is used to regulate the movement of the grinding disc 84;

[0084] The sealing assembly 86 is located on the inner wall of the sampling ring cylinder 12 below the ring opening 82;

[0085] Combination Figure 4 As shown, the inner wall of the annular sample is sealed by the rubber ring bladder 71, and the outer wall of the annular sample is sealed by the sealing component 86. The annular sample is moved upward by adjusting the drill rod 5, and the grinding disc 84 is adjusted by the power mechanism 85 to gradually grind the upper annular surface of the annular sample, so that the solid material and gas formed can enter the annular cavity 81 through the annular opening 82. Through the action of the stirring component 87, the solid material in the annular cavity 81 can be further stirred and crushed, thereby fully expelling the gas in the solid material.

[0086] In this embodiment, the grinding disc 84 includes a carrier ring 841 rotatably connected to the lower end of the ring cover 83, and an abrasive scraper 842 corresponding to the ring opening 82 is provided on the lower circumference of the ring.

[0087] Combination Figure 4 , Figure 7 As shown, the lower end of the abrasive scraper 842 continuously grinds the upper surface of the annular sample, and under the scraping action of the abrasive scraper 842, the ground solid material flows smoothly into the annular opening 82 and then enters the annular cavity 81.

[0088] In this embodiment, the sealing assembly 86 includes:

[0089] Multiple thin plates 861 are arranged circumferentially on the inner wall of the sampling ring cylinder 12;

[0090] An arc plate 862 is disposed between adjacent thin plates 861, and a rollable arc-shaped sleeve 863 is fitted over its exterior.

[0091] Combination Figure 4 , Figure 6 As shown, when the drill rod 5 moves the annular sample upward, the annular sample can drive the arc sleeve 863 to roll, thereby reducing the friction between the outer wall of the annular sample and the inner wall of the sampling ring cylinder 12 while ensuring the sealing effect between them, so that they have a long-term and efficient sealing effect.

[0092] In this embodiment, the stirring assembly 87 includes:

[0093] Hydraulic cylinder 4 871 is located at the bottom of annular cavity 81, and its upper end is provided with bottom ring 872 located in annular cavity 81. Bottom ring 872 is provided with rotatable rotating ring 1 873 and power mechanism 3 875 for regulating the movement of rotating ring 1 873. Magnetic column 1 874 is also provided inside rotating ring 1 873.

[0094] Rotating ring 2 876 rotates on the upper end of bottom ring 872. Inside it is magnetic column 2 877 that attracts magnetic column 1 874. Its outer side wall is provided with scraper 878, and scraper 878 is provided with stirring rod 879 at the upper end of scraper 878.

[0095] Arc-shaped opening 8710 is evenly distributed in a circular pattern on the lower part of the outer wall of the annular cavity 81;

[0096] Arc opening 2 8711 is located on the outer wall of the annular drill barrel 3 and is set in correspondence with arc opening 1 8710;

[0097] Combination Figure 5 As shown, the vertical span of the outer wall of the bottom ring 872 is greater than that of the arc opening 8710. Therefore, when the bottom ring 872 is blocked by the hydraulic cylinder 871, the ring cavity 81 is in the collecting state. After the collecting and monitoring are completed, the hydraulic cylinder 871 adjusts the bottom ring 872 to move down, so that the level where the scraper 878 is located is aligned with the arc opening 8710 and the arc opening 8711. At this time, the rotating ring 873 is rotated by the power mechanism 875, which drives the rotating ring 876 to rotate, thereby driving the scraper 878 to rotate, so that the solid material is discharged outward for the next sampling operation.

[0098] In this embodiment, the gas collection device 9 includes:

[0099] Heating ring 91 is disposed inside the outer wall of ring cavity 81;

[0100] Vent hole 92 is located at the top of annular cavity 81, and a brush rod 843 that interacts with vent hole 92 is connected to the outer end of abrasive scraper 842.

[0101] The transfer chamber 93 is located above the vent hole 92;

[0102] A gas ring box 94 is installed on the sampling ring cylinder 12. Its inlet is connected to the transfer chamber 93, and its inlet is equipped with a valve 95. Its outlet is connected to a vacuum pump 96. A non-dispersive infrared sensor 97 is installed at the top of the box.

[0103] Combination Figure 4 , Figure 8 As shown, heating the solid material through the heating ring 91 facilitates the release of gas from the solid material. The gas accumulates in the transfer chamber 93 through the vent 92. Under the control of the valve 95, the gas in the transfer chamber 93 enters the gas ring box 94 under the vacuum and is collected. The gas is then monitored by the non-dispersive infrared sensor 97.

[0104] In its specific implementation, it includes the following steps:

[0105] Step 1: When the circumferential drill barrel 3 reaches the required sampling position, it retracts through the hydraulic cylinder 2, and at the same time, it rotates by adjusting the drill barrel frame 1 to perform circumferential drilling for a certain length until the required length is reached, forming a cylindrical sample.

[0106] In other words, the drill barrel frame 1 starts to rotate under the drive of external power, which drives the annular drill barrel 3 connected to it via hydraulic cylinder 2 to rotate synchronously. At this time, hydraulic cylinder 2 slowly retracts, causing the annular drill barrel 3 to move downward in an annular drilling manner, cutting an annular groove in the rock layer, leaving an uncut rock column in the center to form a columnar sample. When the drilling reaches the preset depth (i.e. the required sample length), the rotation of the drill barrel frame 1 stops, and the annular drill barrel 3 remains at that depth position.

[0107] Step 2: Start the power mechanism 31 to control the rotation of the rotating seat 32, and then control the drill rod 5 through the hydraulic cylinder 4 to drill a certain length into the center of the cylindrical sample until the required length is reached, forming a ring sample;

[0108] In other words, after the cylindrical sample is formed, it enters the central drilling stage. The power mechanism 31 is started, driving the rotating seat 32 to rotate, thereby driving the hydraulic cylinder 4 at its center and the drill rod 5 connected below to rotate as a whole. At the same time, the hydraulic cylinder 4 extends downward, so that the drill bit 52 at the lower end of the drill rod 5 contacts the upper surface of the cylindrical sample and continues to drill downward.

[0109] During the drilling process, the spring 53 inside the drill rod 5 is in a contracted state, the limiting slider 521 is located at the uppermost end of the limiting slide cavity 511, and the drill bit 52 is in a retracted position relative to the long rod part 51. As the drill bit 52 drills downwards in the center of the cylindrical sample, a central cylindrical cavity of a certain depth is gradually formed. The original cylindrical sample is processed into an annular sample with uniform wall thickness. When the drilling reaches the preset depth (i.e. the required length of the annular sample), the rotation and downward feed of the drill rod 5 are stopped.

[0110] Step 3: Activate the water jet cutting device 6 to horizontally cut the annular sample until the annular sample is severed;

[0111] In other words, after the center drilling is completed, the water jet cutting device 6 is activated to perform bottom transverse cutting. The supply device 61 is activated to deliver ultra-high pressure water (or water abrasive mixture) to the main pipe 62. The water flows through the branch pipe 63 into the jet channel 522 inside the drill bit 52. The pressure of the high-pressure water flow causes the drill bit 52 to overcome the elastic force of the spring 53 and extend downward until the limiting slider 521 slides to the bottom of the limiting slide cavity 511. At this time, the outlet of the jet channel 522 is fully exposed from the lower end of the long rod 51 and is located in the recessed space between the upper end of the drill bit 52 and the lower end of the long rod 51. The outlet is horizontal and points towards the bottom inner wall of the annular sample.

[0112] As the drill rod 5 slowly rotates, multiple jet channels 522 with uniform circumferential distribution simultaneously spray high-pressure water to perform a horizontal annular cut on the bottom of the annular sample. The high-pressure water jet gradually severs the connection between the annular sample and the parent rock below until the annular sample is completely detached.

[0113] Step 4: Activate the fixing device 7 to fix the truncated annular sample on the drill rod 5;

[0114] In other words, after the annular sample is cut, the fixing device 7 is activated, the hydraulic cylinder 73 drives the hydraulic plug 74 to move downward, and the liquid pressure in the hydraulic chamber 72 causes the rubber ring 71 sleeved on the outer wall of the long rod 51 to expand outward. The rubber ring 71 bulges out of the ring groove and fits tightly against the central column cavity wall of the annular sample, generating sufficient frictional clamping force to firmly fix the annular sample to the outside of the drill rod 5.

[0115] Step 5: Adjust the drill rod 5 to reset using hydraulic cylinder 2 4, and simultaneously start the solid material collection device 8 to sample the truncated annular sample;

[0116] In other words, after the fixation is completed, the hydraulic cylinder 4 retracts upward, driving the drill rod 5 and the annular sample fixed outside it to move upward as a whole. During the upward process, the outer wall of the annular sample and the inner wall of the sampling ring cylinder 12 are kept dynamically sealed by the sealing component 86. The annular sample drives the arc bladder sleeve 863 to roll between adjacent thin plates 861, which not only ensures the sealing performance but also reduces the frictional resistance.

[0117] When the drill rod 5 is fully reset to the initial position, the annular sample is located inside the sampling ring cylinder 12, and its upper end face is in contact with the lower end face of the grinding disc 84. At this time, the upper and lower ends of the annular sample are respectively sealed by the sealing component 86 (outer wall) and the rubber ring bladder 71 (inner wall), forming a relatively sealed processing space.

[0118] Step 6: Collect the gas that escaped from the solid material collection device 8 using the gas collection device 9;

[0119] In other words, when entering the solid material collection stage, the second power mechanism 85 is started, driving the grinding disc 84 to rotate. The abrasive scraper 842 at the lower end of the grinding disc 84 contacts the upper annular surface of the annular sample. As the drill rod 5 drives the annular sample to move slowly upward, the abrasive scraper 842 grinds and scrapes the upper annular surface of the annular sample layer by layer. The rock fragments (solid material) generated by grinding are collected inward under the scraping action of the abrasive scraper 842 and fall into the annular cavity 81 below through the annular opening 82.

[0120] The solid material falling into the annular cavity 81 is further processed by the stirring assembly 87. The hydraulic cylinder 871 keeps the bottom ring 872 in the position of the sealing arc 8710, so that the bottom of the annular cavity 81 is closed. The power mechanism 875 drives the rotating ring 873 to rotate. Through the magnetic attraction between the magnetic column 874 and the magnetic column 877, the rotating ring 876 rotates synchronously. This causes the scraper 878 and the stirring rod 879 to continuously stir and crush the solid material in the annular cavity 81, further refining its particle size and fully releasing the gas adsorbed or trapped in the solid material.

[0121] In addition, while the solid material is being crushed and stirred, the gas collection device 9 works simultaneously. The heating ring 91 is energized and heated to moderately heat the solid material in the ring cavity 81, promoting the accelerated precipitation of gas from the solid material. The precipitated gas rises in the ring cavity 81 and is continuously brushed by the brush rod 843 at the outer end of the abrasive scraper 842 to prevent blockage, and smoothly enters the transfer cavity 93 above the vent hole 92.

[0122] At this time, the gas ring box 94 has been pre-evacuated to a vacuum state by the vacuum pump 96, and the valve 95 at its inlet is opened. The gas in the transfer chamber 93 is drawn into the gas ring box 94 for collection under the action of pressure difference. The non-dispersive infrared sensor 97 at the top of the gas ring box 94 detects the concentration of methane and carbon dioxide in the collected gas in real time and outputs the data for analysis.

[0123] Throughout the sampling and processing process, the weighing sensor 11 continuously monitors the overall weight change of the sampling ring cylinder 12. By comparing the empty weight, the weight after loading the ring sample, and the weight after the solid material is discharged, the mass of the collected ring sample can be accurately calculated. This mass data, combined with the gas detection data, can calculate the gas release per unit mass of rock, providing key quantitative basis for determining the gas source (autogenous rock formation or deep seepage).

[0124] The above description is merely a preferred embodiment of the invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A gas sampling device for near-surface rock strata, characterized in that, It includes: The drill barrel frame (1) is fitted with an annular drill barrel (3) on its outside. The annular drill barrel (3) is connected to the drill barrel frame (1) by a hydraulic cylinder (2). Rotary seat (32) is rotatably installed on the upper part of the drill barrel frame (1). A hydraulic cylinder (4) is fixed at its center. The lower output end of the hydraulic cylinder (4) is connected to the drill rod (5). The lower part of the drill rod (5) is provided with a fixing device (7) and a water jet cutting device (6) distributed vertically. A power mechanism (31) for regulating the operation of the rotary seat (32) is provided on the drill barrel frame (1). The weighing sensor (11) is fixedly installed in the lower part of the drill barrel frame (1), and a sampling ring cylinder (12) is provided at its upper end. The sampling ring cylinder (12) is provided with a gas collection device (9) and a solid material collection device (8) distributed vertically.

2. The gas sampling device for near-surface rock strata according to claim 1, characterized in that, The drill pipe (5) includes: The long rod (51) has a limiting slide cavity (511) at its lower end. The drill bit (52) has a limiting slider (521) at its upper end that is slidably connected to the limiting slide cavity (511), and the drill bit (52) is also connected to the long rod part (51) by a spring (53).

3. A gas sampling device for near-surface rock strata according to claim 2, characterized in that, The waterjet cutting device (6) includes: A supply device (61) is located on the upper part of the long rod (51); The main pipe (62) is located inside the long rod section, with its upper end connected to the supply device (61) and its lower end connected to the branch pipe (63). The jet channel (522) is located on the drill bit (52), and its outlet is horizontal. The branch pipe (63) is slidably connected to the inlet of the jet channel (522). When the limiting slider (521) is located at the upper end of the limiting slide cavity (511), the outlet of the jet channel (522) is located inside the lower end of the long rod (51). When the limiting slider (521) is located at the lower end of the limiting slide cavity (511), the outlet of the jet channel (522) is located outside the lower end of the long rod (51).

4. A gas sampling device for near-surface rock strata according to claim 2, characterized in that, The fixing device (7) includes: A rubber ring (71) is fitted onto the outer wall of the long rod (51); The hydraulic chamber (72) is located inside the long rod section. Its lower end is connected to the rubber ring bladder (71), and its upper end is equipped with a hydraulic cylinder three (73). The lower output end of the hydraulic cylinder three (73) is equipped with a hydraulic plug (74).

5. A gas sampling device for near-surface rock strata according to claim 1, characterized in that, The solid material collection device (8) includes: The annular cavity (81) is located inside the wall of the sampling ring cylinder (12), with an annular opening (82) on the upper part of its inner wall and a stirring assembly (87) on its bottom. The ring cover (83) is coaxially sleeved on the outside of the drill rod (5) and located on the inner wall of the sampling ring cylinder (12) above the ring opening (82), with a grinding disc (84) rotating at its lower end. The second power mechanism (85) is located in the ring cover (83) and is used to regulate the movement of the grinding disc (84); The sealing assembly (86) is located on the inner wall of the sampling ring cylinder (12) below the ring opening (82).

6. A gas sampling device for near-surface rock strata according to claim 5, characterized in that, The grinding disc (84) includes a carrier ring (841) rotatably connected to the lower end of the ring cover (83), and an abrasive scraper (842) corresponding to the ring opening (82) is provided on the lower circumference of the ring.

7. A gas sampling device for near-surface rock strata according to claim 5, characterized in that, The sealing assembly (86) includes: Thin plates (861) are arranged in a circular pattern on the inner wall of the sampling ring cylinder (12); An arc plate (862) is disposed between adjacent thin plates (861), and a rollable arc-shaped sleeve (863) is fitted on its outside.

8. A gas sampling device for near-surface rock strata according to claim 5, characterized in that, The stirring assembly (87) includes: Hydraulic cylinder four (871) is located at the bottom of the annular cavity (81), and its upper end is provided with a bottom ring (872) located in the annular cavity (81). The bottom ring (872) is provided with a rotatable rotating ring one (873) and a power mechanism three (875) for regulating the movement of rotating ring one (873). A magnetic column one (874) is also provided inside the rotating ring one (873). Rotating ring 2 (876) rotates at the upper end of bottom ring (872), and is provided with magnetic column 2 (877) that attracts magnetic column 1 (874). It is provided with scraper (878) on its outer side wall, and is provided with stirring rod (879) at the upper end of scraper (878). Arc opening 1 (8710) is evenly distributed in a circular pattern on the lower part of the outer wall of the annular cavity (81); Arc 2 (8711) is located on the outer wall of the ring drill tube (3) and is set in correspondence with arc 1 (8710).

9. A gas sampling device for near-surface rock strata according to claim 6, characterized in that, The gas collection device (9) includes: A heating ring (91) is located inside the outer wall of the ring cavity (81); A vent (92) is provided at the top of the annular cavity (81), and a brush rod (843) that interacts with the vent (92) is connected to the outer end of the abrasive scraper (842). The transfer chamber (93) is located above the vent (92); A gas ring box (94) is located on the sampling ring cylinder (12). Its inlet is connected to the transfer chamber (93), and its inlet is equipped with a valve (95). Its outlet is connected to a vacuum pump (96), and a non-dispersive infrared sensor (97) is installed on the top of its chamber.

10. A method for sampling gas in near-surface rock strata, comprising using a gas sampling device for near-surface rock strata as described in any one of claims 1-9, characterized in that, It includes the following steps: Step 1: When the circumferential drill barrel (3) reaches the required sampling position, it retracts by hydraulic cylinder 1 (2) and rotates by adjusting the drill barrel frame (1) to make a certain length of circumferential drilling until the required length is reached, forming a cylindrical sample; Step 2: Start the power mechanism (31) to control the rotation of the rotating seat (32), and then control the drill rod (5) through the hydraulic cylinder (4) to drill a certain length into the center of the cylindrical sample until the required length is reached, forming a ring sample; Step 3: Start the water jet cutting device (6) to make horizontal cuts on the annular sample until the annular sample is cut off; Step 4: Activate the fixing device (7) to fix the truncated annular sample on the drill rod (5); Step 5: Adjust the drill rod (5) to reset by hydraulic cylinder 2 (4), and at the same time start the solid material collection device (8) to sample the cut-off annular sample; Step 6: Collect the gas that escaped from the solid material collection device (8) using the gas collection device (9).

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