High-pressure sealing micro-damage fixed-point sampling device and method
By using high-pressure sealed micro-loss fixed-point sampling device and method in the determination of coal seam gas content, the problem of gas loss calculation error during the sampling process is solved, and a more accurate measurement of coal seam gas content data is achieved.
Patent Information
- Application Number
- CN202411519681.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2025-02-11
AI Technical Summary
In the existing coal seam gas content measurement methods, there is an error in the calculation of gas loss during the sampling process, resulting in inaccurate data on coal seam gas content.
The high-pressure sealing micro-loss fixed-point sampling device and method are adopted to shorten the time from the beginning of coal drop to the beginning of desorption, and use high-pressure capsule bags and one-way shut-off valves to achieve rapid high-pressure sealing sampling to reduce gas loss.
The coal sample exposure time during the sampling process is shortened, the accuracy of gas content measurement data is improved, and the error between the calculated value of the loss and the true value is reduced.
Smart Images
Figure CN119413494A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of coal seam gas content determination, and in particular relates to a high-pressure sealed micro-loss fixed-point sampling device and method. Background Art
[0002] Coal seam gas content determination (GB / T23250-2009 "Direct underground determination method of coal seam gas content"), the occurrence of coal seam gas in a mine directly determines the gas reserves of the mine and the gas emission of the mine during the production period. The coal seam gas content is an important basic data for calculating the gas reserves of the mine and predicting the gas emission of the mine. Production mines and infrastructure mines generally use the underground desorption method to determine the coal seam gas content.
[0003] The principle of the desorption method for determining the gas content of coal seams is: collect fresh original coal samples underground, measure the gas desorption amount of the coal samples, calculate the gas loss of the coal samples during the sampling process based on the gas desorption law of the coal samples, and then determine the residual gas amount of the coal samples in the laboratory. Finally, calculate the gas content of the coal seam based on the sampling gas loss amount of the coal samples, the underground gas desorption amount, the residual gas amount and the weight of the coal samples.
[0004] 1. Determination method (1) Determination of underground gas desorption The principle of determining the gas content in coal seams is that it is generally believed that the cumulative amount of gas desorbed from the borehole coal sample during the initial exposure period is proportional to the square root of the desorption time of the coal sample, that is: , where V z : Total gas desorption volume of the coal sample from the time of exposure to the time t of desorption measurement, mL; k: proportional constant, ml / min 1 / 2 ; t0: exposure time of coal sample before desorption measurement, min; t: desorption measurement time of coal sample, min.
[0005] The method for measuring the desorption of coal seam gas underground is as follows: Use a drilling rig to drill into the newly exposed coal wall to obtain coal dust, which is then sealed in a can. This period of time should be controlled within 2 minutes. If there are gangue and debris mixed in the coal core, they should be removed. The coal sample must not be washed with water, and it should be canned in its original state without being compacted. It is advisable to leave a gap of 10mm between the coal sample and the can mouth. Connect the coal sample can to the desorber for on-site desorption, and record the tube reading and measurement time at regular intervals for 60 to 120 minutes or when the desorption amount is less than 2cm 3 Read the number every 1 minute within 30 minutes before the start of observation, and read the number every 2 to 5 minutes thereafter.
[0006] (2) Calculation of gas loss According to GB / T23250-2009 "Direct Determination Method of Coal Seam Gas Content Underground", the loss amount calculation method is: the gas desorption amount V determined by desorption is only a part of the total desorption amount of the coal sample, that is, only the desorption amount from t0 to t. The gas amount lost by the coal sample at the exposure time t0 before the desorption determination is ,therefore: ; According to the above formula The horizontal axis is taken as the horizontal axis, and the measured cumulative amount of gas desorption is taken as the vertical axis to draw a graph. The graph is used to determine the measuring points with linear relationships. Then, based on the coordinate values of the measuring points, the loss amount is calculated using the least squares method or the graphical method.
[0007] (3) Determination of residual gas desorption Residual gas desorption amount V of coal sample c The determination is carried out in the laboratory using the natural degassing method; or by measuring the sum of the naturally desorbed gas before crushing, the coal mine desorbed gas and the non-desorbable gas.
[0008] pass The gas loss during the sampling process is calculated by back-calculating the desorption amount and From the relationship graph, we can see that the desorption rate of gas in coal is fast in the initial stage, and then gradually slows down until it approaches the horizontal level. The gas loss amount during the sampling process is calculated by the reverse method, that is, the desorption amount and the square root of time at the beginning of the desorption stage of the coal sample are approximately fitted into a straight line, but the longer the sampling time is, the larger the t0 is, the smaller the slope of the fitted straight line is, and the greater the error between the loss value V2 and the true value is. On the contrary, the shorter the sampling time is, the smaller the t0 is, the larger the slope of the fitted straight line is, and the smaller the error between the loss value V2 and the true value is. Summary of the invention
[0009] The purpose of the present invention is to provide a high-pressure sealed micro-loss fixed-point sampling device and method. The present invention shortens the time t0 from the beginning of coal falling to the beginning of desorption, that is, the desorption curve is moved upward as a whole, so that the calculated loss value V2 is consistent with the true value V 2真 The error is reduced, and more accurate coal seam gas content data is obtained, providing more accurate data for mine gas control work.
[0010] The present invention adopts the following technical solution: A high-pressure sealed micro-loss fixed-point sampling device comprises a sampling tube, one end of the sampling tube is provided with a four-sided drill bit, a high-pressure hole sealer is provided in the sampling tube, the high-pressure hole sealer comprises a seamless steel pipe, the end of the seamless steel pipe close to the four-sided drill bit is a blind head, the other end of the seamless steel pipe is connected to the sampling tube through a connecting head, the other end of the connecting head is provided with a one-way stop valve, the end of the seamless steel pipe close to the blind head is provided with a high-pressure capsule bag, the two ends of the high-pressure capsule bag are anchored to the seamless steel pipe by iron rings, and the part of the surface of the seamless steel pipe located in the high-pressure capsule bag is provided with a guide hole.
[0011] Furthermore, a sealing ring is provided at the connecting end of the sampling tube and the seamless steel pipe.
[0012] Furthermore, the one-way stop valve is connected and sealed to the connector via threads or a quick plug.
[0013] Furthermore, the blind end of the seamless steel pipe is arc-shaped.
[0014] Furthermore, the axes of the sampling tube and the seamless steel pipe are located in the same straight line.
[0015] A high-pressure sealed micro-loss fixed-point sampling method comprises the following steps: S1. After the drill pipe is drilled to the predetermined sampling depth, the drill bit and drill pipe are retracted, and a high-pressure micro-damage fixed-point sampling device is installed at the first section of the drill pipe to perform fixed-point micro-damage sampling; S2. After the high-pressure micro-loss fixed-point sampling device is pushed to the predetermined depth, the drilling rig stops supplying air / water, and the drill rod slowly drills to a depth of 0.8 m. At this time, when the coal sample in the high-pressure micro-loss fixed-point sampling device is sufficient, high-pressure water is connected through the tail end of the drill rod; S3, high-pressure water flows through the inner cavity of the drill pipe, flows through the one-way stop valve, and finally expands the high-pressure capsule bag of the high-pressure sealer to fit tightly with the wall of the sampling tube, thus achieving high-pressure sealing of the coal sample; S4. After the water pressure reaches 4MPa, the water supply is stopped, and the one-way stop valve seals the high-pressure water in the high-pressure sealer to seal the high-pressure capsule bag and the wall of the sampling tube, and the coal sample is sealed between the sampling tube and the high-pressure sealer; S5. Then withdraw the drill pipe, high-pressure micro-loss fixed-point sampling device and four-sided drill bit from the borehole, and then bring the high-pressure sealed micro-loss fixed-point sampling device back to the laboratory to depressurize the one-way stop valve and desorb it, and then obtain the desorption law. Calculate the amount of loss.
[0016] The beneficial effects of the present invention are as follows: 1. The high-pressure micro-loss fixed-point sampling device of the present invention realizes fixed-point sampling in the coal seam and avoids the influence of coal falling from the hole wall due to friction caused by the rotation of the drill rod.
[0017] 2. The high-pressure micro-loss fixed-point sampling device of the present invention utilizes the tight combination of the capsule of the high-pressure capsule bag sealer and the tube wall to achieve rapid high-pressure sealed sampling, and utilizes high-pressure liquid / gas to achieve high-pressure, long-term, tight sealing of the coal sample when the gas pressure on the inner wall of the sampling tube is less than 4MPa.
[0018] 3. The one-way stop valve simplifies the sealing system of the sampling device, and the device has a simple structure, convenient maintenance and easy operation underground.
[0019] 4. The high-pressure micro-loss fixed-point sampling device and method shorten the exposure time of coal samples during the sampling process, making the calculated loss value closer to the actual loss value, and the coal seam gas content measurement result more accurate. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is a structural schematic diagram of the high-pressure sealed micro-loss fixed-point sampling device of the present invention; Figure 2 It is a structural schematic diagram of a high pressure hole sealer; Figure 3 This is a schematic diagram of the high-pressure seal micro-loss fixed-point sampling process of the present invention; Figure 4 This is a schematic diagram of the end of the plugging process of the high-pressure sealing micro-loss fixed-point sampling process of the present invention; Figure 5 This is a schematic diagram of a gas desorption rate measuring device; Figure 6 for Gas loss curve diagram during sampling by back-calculation method; Figure 7 This is the principle diagram of micro-loss sampling of the high-pressure sealed micro-loss fixed-point sampling device; Among them: 1-sampling tube; 2-four-sided drill bit; 3-seamless steel pipe; 4-blind head; 5-connecting head; 6-one-way stop valve; 7-high-pressure capsule bag; 8-iron ring; 9-guide hole; 10-sealing ring; 11-coal sample; 12-drill rod tail end; 13-high-pressure water; 14-drill rod; 15-drill hole; 16-drain outlet; 17-measuring tube; 18-spring clip; 19-bottom plug; 20-exhaust pipe; 21-puncture needle or valve; 22-coal sample tank; 23-lifting ring. DETAILED DESCRIPTION
[0021] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0022] A high-pressure sealed micro-loss fixed-point sampling device comprises a sampling tube 1, one end of the sampling tube 1 is provided with a four-sided drill bit 2, a high-pressure hole sealer is provided in the sampling tube 1, the high-pressure hole sealer comprises a seamless steel tube 3, the end of the seamless steel tube 3 close to the four-sided drill bit 2 is a blind head 4, the other end of the seamless steel tube 3 is connected to the sampling tube 1 through a connector 5, the other end of the connector 5 is provided with a one-way stop valve 6, the end of the seamless steel tube 3 close to the blind head 9 is provided with a high-pressure capsule bag 7, both ends of the high-pressure capsule bag 7 are anchored on the seamless steel tube 3 through iron rings 8, and the partial surface of the seamless steel tube 3 located in the high-pressure capsule bag 7 is provided with a guide hole 9.
[0023] A sealing ring 10 is provided at the connection end of the sampling tube 1 and the seamless steel tube 3 .
[0024] The one-way stop valve 6 is connected and sealed to the connector 5 via threads or a quick plug.
[0025] The blind end 4 of the seamless steel pipe 3 is in an arc shape.
[0026] The axes of the sampling tube 1 and the seamless steel tube 3 are located in the same straight line.
[0027] A high-pressure sealed micro-loss fixed-point sampling method comprises the following steps: S1, after the drill rod 14 is drilled to a predetermined sampling depth, the drill bit and the drill rod 14 are retracted, and a high-pressure micro-damage fixed-point sampling device is installed at the first section of the drill rod 14 to perform fixed-point micro-damage sampling; S2, after the high-pressure micro-loss fixed-point sampling device is pushed to the predetermined depth, the drilling rig stops supplying air / water, and the drill rod 14 slowly drills into a depth of 0.8 m. At this time, when the coal sample in the high-pressure micro-loss fixed-point sampling device is sufficient, the high-pressure water 13 is connected through the drill rod tail end 12; S3, high-pressure water 13 passes through the inner cavity of the drill pipe 14, flows through the one-way stop valve 6, and finally expands the high-pressure capsule bag 7 of the high-pressure sealer to fit tightly with the wall of the sampling tube 1, achieving high-pressure sealing of the coal sample; S4, after the water pressure reaches 4MPa, the water supply is stopped, and the one-way stop valve 6 seals the high-pressure water in the high-pressure sealer to achieve the sealing of the high-pressure capsule bag 7 and the wall of the sampling tube 1, and the coal sample 11 is sealed between the sampling tube 1 and the high-pressure sealer; S5, then withdraw the drill rod 14, the high-pressure micro-loss fixed-point sampling device, and the four-sided drill bit 2 from the borehole 15, and then bring the high-pressure sealed micro-loss fixed-point sampling device back to the laboratory to depressurize the one-way stop valve 6 to obtain the desorption law, and then use Calculate the amount of loss.
Claims
1. A high-pressure sealed micro-loss fixed-point sampling device, characterized in that: The invention comprises a sampling tube (1), one end of which is provided with a four-sided drill bit (2), a high-pressure hole sealer is provided inside the sampling tube (1), the high-pressure hole sealer comprises a seamless steel tube (3), one end of the seamless steel tube (3) close to the four-sided drill bit (2) is a blind head (4), the other end of the seamless steel tube (3) is connected to the sampling tube (1) via a connector (5), the other end of the connector (5) is provided with a one-way stop valve (6), the end of the seamless steel tube (3) close to the blind head (9) is provided with a high-pressure capsule bag (7), both ends of the high-pressure capsule bag (7) are anchored to the seamless steel tube (3) via iron rings (8), and a guide hole (9) is provided on the surface of the seamless steel tube (3) located inside the high-pressure capsule bag (7).
2. A high-pressure sealed micro-loss fixed-point sampling device according to claim 1, characterized in that: A sealing ring (10) is provided at the connection end between the sampling tube (1) and the seamless steel tube (3).
3. A high-pressure sealed micro-loss fixed-point sampling device according to claim 1, characterized in that: The one-way stop valve (6) is connected and sealed to the connector (5) via threads or a quick plug.
4. A high-pressure sealed micro-loss fixed-point sampling device according to claim 1, characterized in that: The blind end (4) of the seamless steel pipe (3) is in an arc shape.
5. The high-pressure sealed micro-loss fixed-point sampling device according to claim 1 is characterized in that: The axes of the sampling tube (1) and the seamless steel tube (3) are located on the same straight line.
6. A sampling method based on the high-pressure sealing micro-loss fixed-point device according to any one of claims 1 to 5, characterized in that: The steps include: S1. After the drill rod (14) has been drilled to a predetermined sampling depth, the drill bit is retracted from the drill rod (14), and a high-pressure micro-damage fixed-point sampling device is installed at the first section of the drill rod (14) to perform fixed-point micro-damage sampling; S2. After the high-pressure micro-loss fixed-point sampling device is pushed to a predetermined depth, the drilling rig stops supplying air / water, and the drill rod (14) slowly drills to a depth of 0.8 m. At this time, when there is enough coal sample in the high-pressure micro-loss fixed-point sampling device, high-pressure water (13) is connected through the rear end (12) of the drill rod; S3, high-pressure water (13) passes through the inner cavity of the drill rod (14), flows through the one-way stop valve (6), and finally expands the high-pressure capsule bag (7) of the high-pressure hole sealer to fit tightly with the wall of the sampling tube (1), thereby achieving high-pressure sealing of the coal sample; S4. After the water pressure reaches 4 MPa, the water supply is stopped, and the one-way stop valve (6) seals the high-pressure water in the high-pressure sealer to seal the high-pressure capsule bag (7) and the wall of the sampling tube (1), thereby sealing the coal sample (11) between the sampling tube (1) and the high-pressure sealer; S5, then withdraw the drill rod (14), the high-pressure micro-loss fixed-point sampling device, and the four-sided drill bit (2) from the borehole (15), and then bring the high-pressure sealed micro-loss fixed-point sampling device back to the laboratory to depressurize the one-way stop valve (6) to obtain the desorption law, and then use Calculate the amount of loss.