[0031] The content of the present invention will be described below in conjunction with specific embodiments.
[0032] Such as Figure 1-Figure 11 As shown, the method for comprehensively judging and predicting gas sources in goafs according to the present invention includes the following steps:
[0033] S1: Determine the main coal seam and gas-containing coal seam of the minefield, and sample the main coal seam and gas-containing coal seam;
[0034] S2: Collect gas in the main coal seam and gas-containing coal seam corresponding to the mark in S1 through the desorption experiment, and test the δ value and gas of the methane carbon, hydrogen isotope, ethane carbon isotope and carbon dioxide stable carbon isotope of the desorbed gas sample Component volume content, where the δ value is a thousandth difference between the isotope ratio of the sample and the isotope ratio of the standard sample;
[0035] S3: Establish multiple standard plates, and project the data of the test hydrocarbon isotopes in S2 into the corresponding standard plates;
[0036] S4: Collect gas mixture samples in the goaf, test the δ values and gas component volume content of methane stable carbon and hydrogen isotopes, ethane carbon isotopes and carbon dioxide stable carbon positions in the mixed gas sample, and test the carbon and hydrogen isotopes The data is cast in the corresponding standard plate;
[0037] S5: Compare the data in S4 with the data in S2, combine with S3, and use the mean interval estimation method to determine the approximate source of gas emission in the goaf.
[0038] In the above scheme, the standard plates in S2 include methane carbon isotope plates, ethane carbon isotope plates, carbon dioxide carbon isotope plates, methane hydrogen isotope plates, methane carbon-ethane carbon isotope comprehensive plates, and ethane carbon-carbon dioxide carbon isotope plates. Comprehensive chart, carbon dioxide-methane hydrogen isotope comprehensive chart, methane carbon-carbon dioxide carbon isotope comprehensive chart, ethane carbon-methane hydrogen isotope comprehensive chart, methane carbon-methane hydrogen isotope comprehensive chart.
[0039] In order to realize the qualitative identification of the gas source in the goaf, this plan also includes the following steps:
[0040] S6: According to S2, determine the volume content of gas components in each coal seam, and determine the source of gas gushing out of the goaf through numerical calculation of isotope fractional sources. The calculation formula is as follows
[0041] σ mix =(v 1 ×a×σ 1 + v 2 ×b×σ 2 + v 3 ×c×σ 3 +v 4 ×d×σ 4 +...+v n ×m×σ n )/[(v 1 + v 2 + v 3 + v 4 +…+ v n )×f], where am refers to the volume content of a certain predetermined component in the main coal seam and gas-containing coal seam corresponding to the mark in S2, and f refers to the volume content of the predetermined component in the gas emitted from the goaf , V 1 -V m Respectively refer to the volume of gas from the main coal seam and gas-containing coal seam corresponding to the mark in S2, σ 1 —Σ n Respectively refer to the δ value of a predetermined component of the hydrocarbon isotope in the gas of the main mining seam and the gas-containing coal seam corresponding to the mark in S2, mix Refers to the δ value of the hydrocarbon isotope of the predetermined component in the gas emitted from the goaf.
[0042] In the above solution, the predetermined components are methane, ethane or carbon dioxide.
[0043] Take a coal seam as an example, figure 1 In the box, the upper and lower bounds of the box represent the 75% and 25% points of the data, the hollow point in the middle of the box represents the average value of the data, and the upper and lower bounds of the vertical line represent the maximum and minimum values of the data, respectively. The hollow triangle Indicates that No. 1 (H1:5302尾巷8#横川里, 9:40 on January 14, 2016), No. 2 (H2:5302尾巷9#横川里, 10:00 on January 14, 2016) lags Hengchuan The average carbon isotope of internal mixed gas. figure 1 Among them, the methane carbon isotope value of coal seam desorbed gas gradually becomes heavier (absolute value becomes smaller) as the depth increases, and the methane carbon isotope value of the desorbed gas of shallow 3, 5, and 7 coal is significantly different, 8-1 # Coal Yishen The desorption gas of each coal seam varies slightly, but it is still gradually heavier. The mixed gas methane carbon isotope value of No. 1 (H1) and No. 2 (H2) lagging Hengchuan in 3# coal mined area is between 5 and 7# coal, and the recovered coal seam is 3# coal, so the gas source is certain Including: 3, 5, 7# coal, which may contain 8-1, 8-2, 9, 15# coal.
[0044] figure 2 Among them, the carbon isotope value of ethane in coal seam desorbed gas gradually becomes heavier (absolute value becomes smaller) as the depth increases, and the carbon isotope value of ethane in desorbed gas of shallow coal 3, 5, 7, 8-1 The difference is obvious. The desorption gas of coal seams of 8-2# has a small change range, but it is still gradually heavier. The carbon isotope value of mixed gas ethane in No. 1 (H1) and No. 2 (H2) lagging Hengchuan of 3# coal goaf is located between 5 and 7# coal, and the recovered coal seam is 3# coal, so its gas source It must include: 3, 5, and 7# coal, which may contain 8-1, 8-2, 9, 15# coal.
[0045] image 3 Among them, the carbon isotope value of carbon dioxide in coal seam desorption gas gradually becomes heavier (absolute value becomes smaller) as the depth increases, and a small inflection point appears at the 8-1# coal. The depth of coal seam desorption gas changes little and the region is stable . No. 1 (H1) and No. 2 (H2) coal goaf of 3# coal goaf. The carbon isotope value of mixed gas in Hengchuan lagging behind is between 3 and 5# coal. Therefore, its gas sources must include: 3, 5# coal, May contain 7, 8-1, 8-2, 9, 15# coal.
[0046] Figure 4 Among them, the methane hydrogen isotope value of coal seam desorbed gas gradually becomes heavier (absolute value becomes smaller) as the depth increases, and the methane hydrogen isotope value of the desorbed gas of coal 3, 5, and 7 in the shallow part is significantly different. , 8-1, 8-2# coal has a relatively small change in hydrogen isotope of desorption gas, while 8-2, 9, 15# coal has a large spacing and a large change in hydrogen isotope value. 3# coal goaf No. 1 (H1), No. 2 (H2) lagging Hengchuan, the mixed gas methane hydrogen isotope value is between 5 and 7# coal, and the coal seam is 3# coal, so the gas source is certain Including: 3, 5, 7# coal, which may contain 8-1, 8-2, 9, 15# coal.
[0047] Figure 5 Among them, the methane (carbon)-ethane (carbon) isotopes in the coal seam desorbed gas gradually become heavier (absolute value becomes smaller) with the increase in depth. No. 1 (H1) and No. 2 (H2) of the 3# coal goaf The content of the methane (carbon)-ethane (carbon) two markers in the lagging Yokogawa is between 5 and 7# coal, and the recovered coal seam is 3# coal. Therefore, its gas sources must include: 3, 5, 7# coal may contain 8-1, 8-2, 9, 15# coal.
[0048] Image 6 Among them, the ethane (carbon)-carbon dioxide (carbon) isotopes in coal seam desorbed gas gradually become heavier (absolute value becomes smaller) with the increase of depth. No. 1 (H1) and No. 2 (H2) of 3# coal goaf The content of ethane (carbon) markers in the lagging Hengchuan is between 5 and 7# coals, while the content of carbon dioxide (carbon) markers is between 3 and 5# coals, and the coal seam is 3# coal. Its gas sources must include: 3, 5, and 7# coal, which may contain 8-1, 8-2, 9, 15# coal.
[0049] Figure 7 Among them, the carbon dioxide (carbon)-methane (hydrogen) isotope values in coal seam desorption gas gradually become heavier (absolute value becomes smaller) with increasing depth. No. 1 (H1) and No. 2 (H2) of 3# coal goaf The content of methane (hydrogen) markers in the lagging Hengchuan are all between 5 and 7# coals, while the content of carbon dioxide (carbon) markers is between 3 and 5# coals, and the recovered coal seam is 3# coal. Gas sources must include: 3, 5, and 7# coal, which may contain 8-1, 8-2, 9, and 15# coal.
[0050] Figure 8 Among them, the methane (carbon)-carbon dioxide (carbon) isotope values in coal seam desorbed gas gradually become heavier (absolute value becomes smaller) as the depth increases. No. 1 (H1) and No. 2 (H2) coal mined areas of 3# The content of methane (carbon) markers in the lagging Hengchuan is between 5 and 7# coals, while the content of carbon dioxide (carbon) markers is between 3 and 5# coals, and the recovered coal seam is 3# coal. Gas sources must include: 3, 5, and 7# coal, which may contain 8-1, 8-2, 9, and 15# coal.
[0051] Picture 9 Among them, the isotope values of ethane (carbon)-methane (hydrogen) in coal seam desorbed gas gradually become heavier (absolute value becomes smaller) as the depth increases. No. 1 (H1) and No. 2 (H2) of 3# coal goaf ) The content of the ethane (carbon)-methane (hydrogen) two markers in the lagging Yokogawa are located between 5 and 7# coal, and the recovered coal seam is 3# coal. Therefore, the gas source must include: 3, 5 , 7# coal may contain 8-1, 8-2, 9, 15# coal.
[0052] Picture 10 Among them, the methane (carbon)-methane (hydrogen) isotope values in coal seam desorbed gas gradually become heavier (absolute value becomes smaller) as the depth increases. No. 1 (H1) and No. 2 (H2) of 3# coal goaf The content of the methane (carbon)-methane (hydrogen) two markers in the lagging Yokogawa is located between 5 and 7# coal, and the recovered coal seam is 3# coal. Therefore, its gas sources must include: 3, 5, 7 # Coal, may contain 8-1, 8-2, 9, 15# coal.
[0053] There are some differences in the stable carbon isotope composition of desorbed gas in different coal seams in this mining area. As the depth increases, the stable carbon isotope in desorbed gas in each coal seam gradually becomes heavier (the absolute value gradually decreases).
[0054] According to the average interval estimation method, it can only be determined that there must be source gas from coal seams 3#, 5#, and 7 during the recovery process of coal 3#, but it cannot be determined whether it contains desorption gas from coal seams deeper than 8-1#. The specific source and The content can be obtained through a calculation model, that is, presumption by mathematical analysis.
[0055] Taking Hengchuan 1 as an example, combining Hengchuan 1 coal seam, gas component and hydrocarbon isotope data, coal seam 3~8-2 gas component content characteristics and gas hydrocarbon isotope characteristics to establish a simultaneous five-element linear equation system, the calculation process is as follows :
[0056] -32.77543=[a×78.80233%×(-34.22358‰)+b×83.235%×(-32.935‰)+c×88.16133%×(-31.21167‰)+d×93.7835%×(-30.35‰)+e× 95.58%×(-29.9425‰)]/[(a+b+c+d+e)×83.60288%] (1)
[0057] -12.35511=[a×0.01325%×(-13.76442‰)+b×0.018%×(-12.835‰)+c×0.0235%×(-11.295‰)+d×0.0265%×(-10.45‰)+e× 0.0295%×(-10.1425‰)]/[(a+b+c+d+e)×0.01811%] (2)
[0058] -12.19567=[a×5.08267%×(-12.61346‰)+b×2.61875%×(-11.84186‰)+c×1.58817%×(-10.99462‰)+d×1.046%×(-10.46901‰)+e× 0.9145%×(-10.21168‰)]/[(a+b+c+d+e)×3.22034%] (3)
[0059] -171.57692=[a×78.80233%×(-175.04683‰)+b×83.235%×(-172.7025‰)+c×88.16133%×(-167.26583‰)+d×93.7835%×(-164.6525‰)+e× 95.58%×(-162.9955‰)]/[(a+b+c+d+e)×83.6 (4)
[0060] 1=a+b+c+d+e (5)
[0061] Transform the equations (1) ~ (5) into
[0062] 0=43.2225×a-1.22438×b-11.542×c-106.20888×d-121.78381×e (1)
[0063] 0=0.041372×a-0.00728×b-0.04168×c-0.05317×d-0.07545×e (2)
[0064] 0=-24.83585×a+8.26333×b+21.81288, ×c+28.32362×d+29.93562×e (3)
[0065] 0=550.22659×a-30.56793×b-402.05338×c-1097.36308×d-1234.78524×e(4)
[0066] 1=a+b+c+d+e (5)
[0067] Construct coefficient matrices A and B.
[0068] A=[43.2225 -1.22438 -11.542 -106.20888 -121.78381;
[0069] 0.041372 -0.00728 -0.04168 -0.05317 -0.07545;
[0070] -24.83585 8.26333 21.81288 28.32362 29.93562;
[0071] 550.22659 -30.56793 -402.05338 -1097.36308 -1234.78524;
[0072] 1 1 1 1 1];
[0073] B=[0;0;0;0;1]
[0074] Using Matlab calculations, it is obtained that the proportions of Hengchuan 1 gas from coal 3~8-2 are 38%, 37%, 12%, 8% and 5% respectively, namely: a=0.38, b=0.37, c= 0.12, d=0.08, e=0.05.
[0075] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement and improvement made within the spirit and principle of the present invention shall be included in the protection of the present invention. Within range.
