Coal bed gas advanced detection sampling device suitable for multi-coal-bed condition

Abstract

According to the coal bed gas advanced detection sampling device suitable for the multi-coal-bed condition, an adjustable sampler with an upper sealer and a lower sealer is arranged, the sealing position is controlled by combining an electric telescopic rod, accurate packing of a target coal bed is achieved, coal bed gas is collected through cooperation of an exhaust fan and a sampling bottle, and the sampling efficiency is improved. The sampling process is stable and reliable, residual gas in the lower exploring pipe can be exhausted through the exhaust system, upper-layer coal bed gas is prevented from interfering follow-up sampling, in addition, a gas isolation belt is formed by injecting high-pressure inert gas into the shaft, longitudinal migration and mixing of multiple coal bed gas bodies are further prevented, and the device is reasonable in overall structure, convenient to operate and high in practicability. The problem of data distortion caused by gas mixing in traditional multi-coal-seam sampling can be effectively solved, the layering precision and sample representativeness of sampling are remarkably improved, and reliable technical support is provided for scientific evaluation and accurate mining of coal-seam gas resources.

Description

Technical Field

[0001] The present invention relates to a detection and sampling device, in particular to a coalbed methane advanced detection and sampling device applicable to multi - coal seam conditions in the sampling field. Background Art

[0002] The coalbed methane advanced detection and sampling device for multi - coal seam conditions refers to, after the drilling is completed, by setting a special sampling device in the well, successively extracting coalbed methane samples from multiple coal seams at different depths. This technology can accurately obtain parameters such as gas content, composition, and pressure of each coal seam, and has the characteristics of layered sampling and real data, providing a reliable basis for coalbed methane resource evaluation, layered development, and optimization of mining plans.

[0003] Chinese Patent with publication number CN117367897B discloses a self - sealing coalbed methane sampling device, which lowers a sampling bag to the position of coalbed methane and samples and collects coalbed methane through the sampling bag.

[0004] The above - mentioned patent is only applicable to the sampling of single - coalbed methane. In the sampling of multi - coalbed methane, there is often a problem of mixed gas interfering with sampling, that is, the gas mixture of the upper coal seam and the lower coal seam, resulting in the mixing of components and distortion of data in the gas samples collected from different coal seams, affecting the accuracy of layered evaluation. Therefore, effectively isolating each coal seam and controlling the gas passage is the key to improving the sampling accuracy of multi - coal seams. Summary of the Invention

[0005] Aiming at the above - mentioned prior art, the technical problem to be solved by the present invention is that the mixed gas interference in multi - coalbed methane sampling means that the coalbed methane in the upper coal seam rushes into the lower sampling area along the wellbore, resulting in the mixing of sample components and distortion of data.

[0006] To solve the above problems, the present invention provides a coalbed methane advanced detection and sampling device applicable to multi - coal seam conditions, including a pressure - maintaining well and a sampler. The sampler includes a suction fan and a fixed pipe. A down - exploration pipe is fixedly connected between the top end of the fixed pipe and the input end of the suction fan. The inner wall of the top end of the fixed pipe is fixedly connected with an electric telescopic rod. The output end of the electric telescopic rod is fixedly connected with an adjusting rod, and the adjusting rod is in sealed sliding connection with the inner wall of the fixed pipe. The outer wall of the fixed pipe is provided with air intake holes. The output end of the suction fan is communicated with a sampling bottle. The outer walls of the fixed pipe and the adjusting rod are both fixedly connected with upper sealers and lower sealers. Each of the upper sealers and lower sealers includes an inner frame and an inner pressure pump. The outer wall of the inner frame is fixedly connected with an inner sealing bag. The output end of the inner pressure pump is communicated with the inner sealing bag. The side wall of the inner sealing bag is fixedly connected with an air release pipe, and one end of the air release pipe is fixedly connected with an electromagnetic valve.

[0007] As a further improvement of the present application, the pressure - maintaining well includes a wellhead. The inner wall of the top end of the wellhead is fixedly connected with an annular frame, and the inner wall of the annular frame is fixedly connected with an outer sealing bag.

[0008] As a further improvement of the present application, an external pressure pump is fixedly connected to the side wall at the top of the wellhead. An external pressure pipe is connected between the output end of the external pressure pump and the external seal bag.

[0009] As a further improvement of the present application, the pressure-holding well further includes a compressor. A gas guide pipe is fixedly connected between the output end of the compressor and the wellhead. The input end of the compressor is connected to a gas storage cylinder, and an inert gas is filled inside the gas storage cylinder.

[0010] As another improvement of the present application, the exhaust fan and the sampling bottle are connected through a connecting pipe. A drain pipe is fixedly connected to the side wall of the connecting pipe. A first valve and a second valve are respectively fixedly connected to one end of the drain pipe and the connecting pipe.

[0011] As a supplement to another improvement of the present application, four driving wheels distributed in a rectangular shape are rotatably connected to the inner wall of the wellhead. The driving wheels are in transmission connection with the downhole pipe. A driver is fixedly connected to the outer wall of the wellhead, and the driver is used to drive the driving wheels to rotate.

[0012] As a supplement to another improvement of the present application, a positioning frame is fixedly connected to the side wall of the wellhead. A sponge block is fixedly connected to the inner wall of the positioning frame. A lubricating fluid is filled inside the sponge block. An oil filling hole is opened at the top of the positioning frame.

[0013] In summary, the present invention effectively isolates a single coal seam to prevent the interference of mixed gases. By setting controllable upper and lower sealing devices on the sampler, which are respectively located at the upper and lower interfaces of the target coal seam, and using an internal pressure pump to drive the seal bag to expand and closely fit with the well wall to form a closed space, the gas channels between the upper and lower coal seams can be effectively isolated. This structure realizes the independent sealing of a single coal seam, eliminating the possibility of gas migration from the upper coal seam to the lower layer and interfering with the lower layer sampling from the source, and significantly improving the accuracy and representativeness of the stratified sampling data. The present invention ensures the sampling efficiency and gas integrity by setting an air extraction and sampling device. This device uses an exhaust fan to extract coal seam gas from the closed coal seam area and transports it to the sealed sampling bottle through a connecting pipe, realizing a sampling process with low interference and stable flow. The air extraction process is completed in a sealed environment, avoiding gas leakage or doping with other gas sources in the wellbore, ensuring the originality and integrity of the sample gas composition, and meeting the requirements for the sample quality in subsequent component analysis and gas measurement. The present invention avoids cross-contamination by providing residual gas discharge. Since the sampling device moves sequentially between multiple coal seams, it is inevitable that gas from the previous coal seam remains in the downhole pipe and the pipeline. To address this problem, the present invention is provided with a drain pipe and control valves on the connecting pipe, which can perform directional evacuation of the gas inside the system before sampling to remove the residual sample gas and avoid the mixing of the gas from the upper coal seam into the current sampling gas. This measure improves the layer correspondence of the samples and ensures the physical isolation and data independence between the samples of each coal seam. In the present invention, the wellbore space is filled with an inert gas to form a longitudinal isolation barrier. During the process of moving the sampler to the next coal seam, high-pressure inert gas (such as nitrogen or helium) is filled into the wellbore through an external compressor, forming a physical gas isolation barrier between the coal seams. The inert gas has the characteristics of not participating in reactions, high density, and easy-to-control flow, which can effectively block the vertical penetration and diffusion of gases between coal seams, further avoiding the contamination of samples by mixed gases, and enhancing the tightness and credibility of the sampling process. Description of the Drawings

[0014] Figure 1 It is a front view of the whole in the first and second embodiments of the present application; Figure 2 It is a connection structure diagram at the wellhead in the first and second embodiments of the present application; Figure 3 It is a front sectional view at the fixed pipe in the first and second embodiments of the present application; Figure 4 It is a front sectional view at the inner sealing capsule in the first and second embodiments of the present application; Figure 5 It is a state diagram when the upper sealing device and the lower sealing device are respectively located on the upper and lower sides of the coal seam in the first and second embodiments of the present application; Figure 6 It is a front sectional view at the wellhead in the second embodiment of the present application; Figure 7 It is a top view at the drain pipe in the second embodiment of the present application.

[0015] Explanation of the reference numerals in the drawings: 1, exhaust fan; 101, fixed pipe; 102, lower exploration pipe; 103, sampling bottle; 104, electric telescopic rod; 105, adjusting rod; 106, air inlet hole; 2, wellhead; 201, ring frame; 202, outer sealing capsule; 203, outer pressure pump; 204, outer pressure pipe; 205, compressor; 206, gas guide pipe; 207, gas storage cylinder; 208, driving wheel; 209, driver; 210, positioning frame; 211, sponge block; 212, oil filling hole; 3, connecting pipe; 301, drain pipe; 302, first valve; 303, second valve; 4, inner frame; 401, inner pressure pump; 402, inner sealing capsule; 403, gas discharge pipe; 404, solenoid valve. Specific Embodiments

[0016] The following will describe the two embodiments of the present application in detail with reference to the drawings.

[0017] The first embodiment: Figures 1-5Disclosed is a coalbed methane advanced detection and sampling device applicable to multi - coal - seam conditions, including a pressure - maintaining well and a sampler. The sampler includes a suction fan 1 and a fixed pipe 101. A down - exploration pipe 102 is fixedly connected between the top end of the fixed pipe 101 and the input end of the suction fan 1. An electric telescopic rod 104 is fixedly connected to the inner wall of the top end of the fixed pipe 101. The output end of the electric telescopic rod 104 is fixedly connected to an adjusting rod 105. The adjusting rod 105 is hermetically and slidably connected to the inner wall of the fixed pipe 101. An air inlet hole 106 is formed in the outer wall of the fixed pipe 101. The output end of the suction fan 1 is communicated with a sampling bottle 103. Upper sealers and lower sealers are fixedly connected to the outer walls of both the fixed pipe 101 and the adjusting rod 105. Each of the upper sealer and the lower sealer includes an inner frame 4 and an inner pressure pump 401. An inner sealing bag 402 is fixedly connected to the outer wall of the inner frame 4. The output end of the inner pressure pump 401 is communicated with the inner sealing bag 402. A gas discharge pipe 403 is fixedly connected to the side wall of the inner sealing bag 402. One end of the gas discharge pipe 403 is fixedly connected to an electromagnetic valve 404.

[0018] When sampling, the fixed pipe 101 is lowered into the sampling well through the pressure - maintaining well until the upper sealer is located above the coal seam. Then, the lower sealer is adjusted to be located below the coal seam through the electric telescopic rod 104. The inner pressure pump 401 is started to inflate the inside of the inner sealing bag 402, so that the inner sealing bag 402 is closely attached to the well wall, playing a role in sealing the coal seam. After the coal seam is sealed, the suction fan 1 is started to extract the coalbed methane and discharge it into the sampling bottle 103, completing the sampling of the coal seam.

[0019] When sampling the next coal seam, the electromagnetic valve 404 is opened to release the gas inside the inner sealing bag 402, so that the inner sealing bag 402 loosens the well wall, and the fixed pipe 101 descends to the next coal seam for sampling.

[0020] Through the above - mentioned setting, when sampling multiple coal seams in sequence, it can play a role in sealing the coal seam, preventing the gas of other coal seams from interfering with the sampled samples, and greatly improving the accuracy of the sampling results.

[0021] The present invention effectively isolates a single coal seam to prevent the interference of mixed gases. By setting controllable upper and lower sealing devices on the sampler, which are respectively located at the upper and lower interfaces of the target coal seam, and using an inner pressure pump to drive the sealing bag to expand and closely fit with the well wall to form a closed space, it can effectively isolate the gas channels between the upper and lower coal seams. This structure realizes the independent sealing of a single coal seam, eliminating the possibility of the gas of the upper coal seam migrating downward and interfering with the sampling of the lower coal seam from the source, and significantly improving the accuracy and representativeness of the stratified sampling data.

[0022] The present invention ensures the sampling efficiency and gas integrity by setting up an air extraction and sampling device. This device uses a suction fan to extract coalbed methane from the enclosed coal seam area and transports it through a connecting pipe into a sealed sampling bottle, realizing a sampling process with low interference and stable flow. The air extraction process is completed in a sealed environment, avoiding gas leakage or admixture with other gas sources in the wellbore, ensuring the originality and integrity of the sample gas composition, and meeting the requirements for the sample quality in subsequent component analysis and gas determination.

[0023] The second implementation mode: Figures 1-7 There is shown a coalbed methane advanced detection sampling device applicable to multi - coal - seam conditions. Different from the first implementation mode, the pressure - maintaining well includes a wellhead 2. The inner wall at the top of the wellhead 2 is fixedly connected with a ring frame 201. The inner wall of the ring frame 201 is fixedly connected with an outer sealing bladder 202. The side wall at the top of the wellhead 2 is fixedly connected with an outer pressure pump 203. There is an outer pressure pipe 204 communicating between the output end of the outer pressure pump 203 and the outer sealing bladder 202. The pressure - maintaining well further includes a compressor 205. There is a gas guide pipe 206 fixedly connected between the output end of the compressor 205 and the wellhead 2. The input end of the compressor 205 is communicated with a gas storage cylinder 207, and the inside of the gas storage cylinder 207 is filled with inert gas.

[0024] Through the above - mentioned setting, when the fixed pipe 101 moves to sample different coal seams, to prevent the gas between multiple coal seams from mixing, the compressor 205 can be started to fill the inside of the sampling well with high - pressure inert gas. At this time, when the fixed pipe 101 moves, the coalbed methane is squeezed into the inside of the coal seam, and the situation of mixing between multiple coalbed methane can be prevented.

[0025] The suction fan 1 and the sampling bottle 103 are connected through a connecting pipe 3. The side wall of the connecting pipe 3 is fixedly connected with a discharge pipe 301. The discharge pipe 301 and one end of the connecting pipe 3 are respectively fixedly connected with a first valve 302 and a second valve 303. When using the sampling bottle 103 to collect coalbed methane, the sampling bottle 103 is connected to the connecting pipe 3. When sampling different coal seams, the inside of the down - hole pipe 102 will have residues of the sample from the previous coal seam, affecting the accuracy of the sample. Through the above - mentioned setting, when collecting samples from different coal seams, the first valve 302 can be opened, the second valve 303 can be closed to empty the residues of the sample inside the down - hole pipe 102. After emptying for a period of time, the first valve 302 is closed, and the second valve 303 is opened to fill the inside of the sampling bottle 103 with the coalbed methane sample.

[0026] The present invention is provided with residual gas discharge to avoid cross - contamination. Since the sampling device moves successively between multiple coal seams, it is inevitable that the gas of the previous coal seam remains in the down - hole probe and the pipeline. To solve this problem, the present invention is provided with a discharge pipe and a control valve on the connecting pipe, which can direct the evacuation of the gas inside the system before sampling, remove the residual sample gas, and avoid the mixing of the coal seam gas of the upper layer into the current sampling gas. This measure improves the layer correspondence of the samples and ensures the physical isolation and data independence between the samples of each coal seam.

[0027] The present invention forms a longitudinal isolation barrier by filling the wellbore space with inert gas. During the process of moving the sampler to the next coal seam, the present invention fills the wellbore with high - pressure inert gas, such as nitrogen or helium, through an external compressor, forming a physical gas isolation barrier between the coal seams. Inert gas has the characteristics of not participating in reactions, high density, and easy - to - control flow, which can effectively block the vertical penetration and diffusion of gas between coal seams, thus further avoiding the contamination of samples by mixed gas and enhancing the tightness and credibility of the sampling process.

[0028] The inner wall of the wellhead 2 is rotatably connected with four driving wheels 208 distributed in a rectangle. The driving wheels 208 are in transmission connection with the down - hole probe 102. The outer wall of the wellhead 2 is fixedly connected with a driver 209, and the driver 209 is used to drive the driving wheels 208 to rotate. Through the above - mentioned setting, the driving wheels 208 can drive the down - hole probe 102 to drive the fixed pipe 101 to move up and down to different coal seams.

[0029] The side wall of the wellhead 2 is fixedly connected with a positioning frame 210. The inner wall of the positioning frame 210 is fixedly connected with a sponge block 211. The inside of the sponge block 211 is filled with lubricating fluid. The top of the positioning frame 210 is provided with an oil - filling hole 212. Through the above - mentioned setting, the sponge block 211 can evenly apply the lubricating fluid to the surface of the down - hole probe 102 through the driving wheels 208, reducing the friction between the down - hole probe 102 and the outer sealing capsule 202, so that the down - hole probe 102 can better pass through the outer sealing capsule 202.

[0030] Combined with the current actual requirements, the above - mentioned implementation manner adopted by the present application does not limit the protection scope thereto. Within the knowledge scope of those skilled in the art, various changes made without departing from the concept of the present application still fall within the protection scope of the present invention.

Claims

1. A coalbed methane advanced detection and sampling device applicable to multi - coal seam conditions, comprising a pressure - maintaining well and a sampler, characterized in that: The sampler includes a suction fan (1) and a fixed pipe (101). A down - probe pipe (102) is fixedly connected between the top end of the fixed pipe (101) and the input end of the suction fan (1). The inner wall of the top end of the fixed pipe (101) is fixedly connected with an electric telescopic rod (104). The output end of the electric telescopic rod (104) is fixedly connected with an adjusting rod (105). The adjusting rod (105) is hermetically and slidably connected with the inner wall of the fixed pipe (101). An air inlet hole (106) is formed in the outer wall of the fixed pipe (101). The output end of the suction fan (1) is communicated with a sampling bottle (103). Upper seals and lower seals are fixedly connected to the outer wall of the fixed pipe (101) and the outer wall of the adjusting rod (105). Each of the upper seal and the lower seal includes an inner frame (4) and an inner pressure pump (401). An inner seal bag (402) is fixedly connected to the outer wall of the inner frame (4). The output end of the inner pressure pump (401) is communicated with the inner seal bag (402). A gas discharge pipe (403) is fixedly connected to the side wall of the inner seal bag (402). One end of the gas discharge pipe (403) is fixedly connected with an electromagnetic valve (404).

2. The coalbed methane advanced detection and sampling device applicable to multi-seam conditions according to claim 1, characterized in that: The pressure - maintaining well includes a wellhead (2). An annular frame (201) is fixedly connected to the inner wall of the top end of the wellhead (2). An outer seal bag (202) is fixedly connected to the inner wall of the annular frame (201).

3. The coalbed methane advanced detection and sampling device applicable to multi-seam conditions according to claim 2, characterized in that: An outer pressure pump (203) is fixedly connected to the side wall of the top end of the wellhead (2). An outer pressure pipe (204) is communicated between the output end of the outer pressure pump (203) and the outer seal bag (202).

4. The coalbed methane advanced detection and sampling device applicable to multi-seam conditions according to claim 3, wherein: The pressure - maintaining well further includes a compressor (205). A gas guide pipe (206) is fixedly connected between the output end of the compressor (205) and the wellhead (2). The input end of the compressor (205) is communicated with a gas storage cylinder (207). The inside of the gas storage cylinder (207) is filled with inert gas.

5. The coalbed methane advanced detection and sampling device applicable to multi - coal - seam conditions according to claim 1, wherein: The suction fan (1) and the sampling bottle (103) are communicated through a connecting pipe (3). A drain pipe (301) is fixedly connected to the side wall of the connecting pipe (3). A first valve (302) and a second valve (303) are respectively fixedly connected to one end of the drain pipe (301) and the connecting pipe (3). When using the sampling bottle (103) to collect coal - bed methane, the sampling bottle (103) is connected to the connecting pipe (3).

6. The coalbed methane advanced detection and sampling device applicable to multi - coal - seam conditions according to claim 2, wherein: Four driving wheels (208) distributed in a rectangular shape are rotatably connected to the inner wall of the wellhead (2). The driving wheels (208) are in transmission connection with the down - probe pipe (102). A driver (209) is fixedly connected to the outer wall of the wellhead (2).

7. The coalbed methane advanced detection and sampling device applicable to multi - coal - seam conditions according to claim 2, wherein: A positioning frame (210) is fixedly connected to the side wall of the wellhead (2). A sponge block (211) is fixedly connected to the inner wall of the positioning frame (210). The inside of the sponge block (211) is filled with lubricating fluid. An oil - filling hole (212) is formed in the top end of the positioning frame (210).

Images