Coal seam gas loss measuring method

Abstract

The invention discloses a coal seam gas loss amount measuring method, which comprises the following steps: drilling a hole in a coal seam to a position to be subjected to coal sample taking, enabling gas balance in the drill hole, and measuring the amount of gas released by the drill hole in unit time; secondary drilling is conducted for a certain distance, the time spent from the beginning of secondary drilling to coal body blowing-out, gas release started when the coal body is broken and gas concentration increase at a hole opening are recorded, the total gas loss amount generated by the wall face of a drill hole and coal drilling-out in the drilling process is counted, then the coal body blown out through secondary drilling is weighed, and the coal body blown out through secondary drilling is obtained. The total gas loss amount is the sum of the original gas loss amount in the drill hole and the gas loss amount of the newly exposed coal body, and then the gas loss amount of the coal body with the unit mass is accurately calculated.

Description

Technical Field

[0001] This invention relates to the field of coal mine safety, and in particular to a method for measuring coal seam gas loss. Background Technology

[0002] Coal seam gas loss refers to the amount of gas lost from a coal sample during a specific process, and is an important concept in coal seam gas content determination. Coal seam gas loss is affected by various factors, including the coal seam's occurrence conditions, coal sample properties, and the measurement method. Coal seam gas loss mainly includes loss during the process of the coal sample leaving the coal body, loss during transportation and storage, and loss during the measurement process.

[0003] In existing technologies, determining coal seam gas content requires drilling a borehole, extracting a coal sample, and then desorbing the sample. During desorption, gas is gradually released, and the total amount of released gas is calculated. The gas content is the sum of gas loss, gas desorption, and residual gas. When the coal sample is extracted from the original coal seam by drilling, gas release begins as soon as the sample is exposed. The process of sampling and loading the sample into a sealed container takes time, resulting in gas loss, which accounts for a significant portion of the actual measured gas content.

[0004] Regarding the aforementioned technologies, the traditional method for determining gas loss involves using empirical formulas to calculate the amount of gas loss. This method uses the time from coal sample exposure to containerization as the main parameter for back-calculation, which results in a large error and makes it impossible to accurately calculate the gas loss of the coal seam. Summary of the Invention

[0005] In order to accurately calculate the amount of coalbed methane loss, this application provides a method for measuring the amount of coalbed methane loss.

[0006] This application provides a method for determining coal seam gas loss, employing the following technical solution: A method for determining coal seam gas loss includes: S1: Drill a hole into the coal seam using drilling equipment. After drilling to the location where the coal sample is to be taken, stop drilling and blow air into the hole to expel all the coal and bring the gas into equilibrium. At this point, measure the volumetric flow rate of the air at the hole opening. and gas concentration ,flow The product of the gas concentration and the amount of gas released per unit time in borehole (3) is the amount of gas released per unit time. , , The unit is m³ / min. The unit is m³ / min. The unit is % S2: Secondary drilling into the coal seam, drilling distance... Then the coal was blown out; and the time taken from the start of the second drilling to the coal being blown out was recorded. The unit is min; drilling distance All the coal within the borehole changes from its original state to a broken state. This breakage begins to release methane gas, leading to an increase in methane concentration at the borehole opening. The total methane loss during drilling, caused by the borehole wall and coal extraction, is then tallied. , , The unit is m³ / min; S3: Second drilling distance The coal ejected during the process is collected and weighed; the mass is... , The unit is kg; the volumetric flow rate of the air at the orifice was measured again. and gas concentration And calculate the drilling distance. After stopping, the amount of gas released per unit time , ; The unit is m³ / min. The unit is m³ / min. The unit is % S4: The total gas loss is the sum of the original gas loss in the borehole and the gas loss from the newly exposed coal seam. The gas loss per unit mass of coal seam is... ,Right now In the formula Therefore, it can be calculated that , The unit is m³ / min.

[0007] Optionally, the drilling equipment is a pneumatic drill. Compressed air from the pneumatic drill enters the borehole and then comes out. The compressed air carries gas and coal and blows it out from the borehole opening. The air volume of the pneumatic drill is the air volume at the borehole opening.

[0008] Optionally, between S1 and S2, the compressed air can be reduced to ensure that the coal dust generated during subsequent drilling falls into the borehole.

[0009] Optionally, a flow meter may be used when measuring the volumetric flow rate of the air at the orifice.

[0010] In summary, this application includes at least one of the following beneficial technical effects: 1. First, drill a hole into the coal seam to the location where the coal sample is to be taken, and then bring the gas in the hole to a state of gas equilibrium. Measure the amount of gas released per unit time in the hole. Drill a certain distance a second time and record the time taken from the start of the second drilling to the coal body being blown out. The coal body breaks and begins to release gas, and the gas concentration at the borehole opening increases. Calculate the total gas loss caused by the borehole wall and the coal being blown out during the drilling process. Then weigh the coal body blown out during the second drilling and calculate the amount of gas released per unit time after the second drilling stops. The total gas loss is the sum of the original gas loss in the borehole and the gas loss of the newly exposed coal body. Then, accurately calculate the gas loss per unit mass of coal body. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the overall structure of a method for measuring coal seam gas loss according to an embodiment of this application.

[0012] Explanation of reference numerals in the attached diagram: 1. Drilling equipment; 2. Coal seam; 3. Borehole; 4. Orifice; 5. Flow meter. Detailed Implementation

[0013] The present application will be further described in detail below with reference to all the accompanying drawings.

[0014] This application discloses a method for measuring coal seam gas loss.

[0015] Example Reference Figure 1 A method for determining coal seam gas loss, comprising: S1: Drill hole 3 into coal seam 2 using drilling equipment 1. After drilling to the position where coal sample is to be taken for the first time, stop drilling and blow air into the borehole 3 to blow out all the coal in the borehole 3 and make the borehole 3 reach a gas balance state. Drilling equipment 1 uses a pneumatic drill. The pneumatic drill pressurized air enters the borehole 3 and comes out from the borehole 3. The pressurized air carries gas and coal and blows it out from the hole opening 4. The air volume of the pneumatic drill pressurized air is the air volume at the hole opening 4.

[0016] At this time, the volumetric flow rate of the wind was measured at point 4 of the orifice. and gas concentration When measuring the volumetric flow rate of the air at orifice 4, flow meter 5 is used; flow rate The product of the gas concentration and the amount of gas released per 3 unit time in the borehole is the amount of gas released. , , The unit is m³ / min. The unit is m³ / min. The unit is %; reduce the compressed air to ensure that the coal dust generated during subsequent drilling falls into borehole 3.

[0017] S2: Secondary drilling into coal seam 2, drilling distance... Then the coal was blown out; and the time taken from the start of the second drilling to the coal being blown out was recorded. The unit is min; drilling distance All the coal within the borehole changed from its original state to a broken state. The breaking of the coal began to release gas, which in turn increased the gas concentration at the borehole opening. The total gas loss during drilling due to the borehole wall and coal extraction was calculated. , , The unit is m³ / min.

[0018] S3: Second drilling distance The coal ejected during the process is collected and weighed; the mass is... , The unit is kg; the volumetric flow rate of the air at the four orifice openings was measured again. and gas concentration And calculate the drilling distance. After stopping, the amount of gas released per unit time , ; The unit is m³ / min. The unit is m³ / min. The unit is %.

[0019] S4: The total gas loss is the sum of the original gas loss in borehole 3 and the gas loss from the newly exposed coal seam. The gas loss per unit mass of coal seam is... ,Right now In the formula Therefore, it can be calculated that , The unit is m³ / min.

[0020] The implementation principle of the method for measuring coal seam gas loss in this application embodiment is as follows: First, a drill hole 3 is drilled into the coal seam 2 using drilling equipment 1 to the location where the coal sample is to be taken. Then, the gas in the drill hole 3 is brought into gas equilibrium, and the amount of gas released per unit time in the drill hole 3 is measured. A certain distance is drilled a second time, and the time taken from the start of the second drilling to the coal body being blown out is recorded. The coal body breaks and begins to release gas, and the gas concentration at the borehole opening 4 increases. The total gas loss caused by the wall of the drill hole 3 and the coal produced during the drilling process is calculated. The coal body blown out during the second drilling is weighed, and the amount of gas released per unit time after the second drilling stops is calculated. The total gas loss is the sum of the original gas loss in the drill hole 3 and the gas loss of the newly exposed coal body, thereby accurately calculating the gas loss per unit mass of coal body.

[0021] In the description of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] In the description of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0024] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for determining coal seam gas loss, characterized in that: include: S1: Using drilling equipment (1), drill a hole (3) into the coal seam (2). After drilling to the position where the coal sample is to be taken for the first time, stop drilling and blow air into the hole (3) to blow out all the coal in the hole (3) and make the hole (3) reach a gas balance state. At this time, the volumetric flow rate of the air is measured at the hole opening (4). and gas concentration ,flow The product of the gas concentration and the amount of gas released per unit time in borehole (3) is the amount of gas released per unit time. , , The unit is m³ / min. The unit is m³ / min. The unit is % S2: Secondary drilling into coal seam (2), drilling distance Then the coal was blown out; and the time taken from the start of the second drilling to the coal being blown out was recorded. The unit is min; drilling distance All the coal within the borehole changes from its original state to a broken state. The broken coal begins to release gas, which in turn increases the gas concentration at the borehole opening (4). The total gas loss during drilling due to the borehole wall (3) and coal extraction is calculated. , , The unit is m³ / min; S3: Second drilling distance The coal ejected during the process is collected and weighed; the mass is... , The unit is kg; the volumetric flow rate of the air at the orifice (4) was measured again. and gas concentration And calculate the drilling distance. After stopping, the amount of gas released per unit time , ; The unit is m³ / min. The unit is m³ / min. The unit is % S4: The total gas loss is the sum of the original gas loss in borehole (3) and the gas loss of the newly exposed coal seam. The gas loss per unit mass of coal seam is... ,Right now In the formula Therefore, it can be calculated that , The unit is m³ / min.

2. The method for determining coal seam gas loss according to claim 1, characterized in that: The drilling equipment (1) uses a pneumatic drill. The compressed air from the pneumatic drill enters the borehole (3) and then comes out from the borehole (3). The compressed air carries the gas and coal and blows it out from the hole opening (4). The compressed air volume of the pneumatic drill is the air volume at the hole opening (4).

3. The method for determining coal seam gas loss according to claim 1, characterized in that: Between S1 and S2, reduce the compressed air to ensure that the coal dust generated during subsequent drilling falls into the borehole (3).

4. The method for determining coal seam gas loss according to claim 1, characterized in that: A flow meter (5) is used to measure the volumetric flow rate of the air at the orifice (4).

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