CN110991081B - Method for determining gas extraction amount of adjacent layer based on gas extraction of ground drilling - Google Patents
Method for determining gas extraction amount of adjacent layer based on gas extraction of ground drilling Download PDFInfo
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- 238000005553 drilling Methods 0.000 title claims abstract description 102
- 238000000605 extraction Methods 0.000 title claims abstract description 55
- 238000000034 method Methods 0.000 title claims abstract description 14
- 239000003245 coal Substances 0.000 claims abstract description 54
- 238000010276 construction Methods 0.000 claims description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 6
- 229910052799 carbon Inorganic materials 0.000 abstract description 6
- 239000007789 gas Substances 0.000 description 124
- 239000010410 layer Substances 0.000 description 23
- 238000005065 mining Methods 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 238000004445 quantitative analysis Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
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- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F7/00—Methods or devices for drawing- off gases with or without subsequent use of the gas for any purpose
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Abstract
The invention discloses a method for determining gas extraction amount of adjacent layers based on gas extraction of ground drilling, wherein high-level drilling is constructed around the ground drilling so that the two are positioned at the same extraction layer; then, respectively extracting gas from the ground drilling hole and the high-level drilling hole, and measuring the concentration of the gas extracted from the high-level drilling hole, the concentration of the gas extracted from the ground drilling hole and the flow of the gas extracted from the ground drilling hole; and then constructing a ground drilling extraction multi-coal-bed gas split-source calculation model according to the mass conservation law, namely, the pure gas quantity flowing into the ground hole in unit time is equal to the pure gas quantity flowing out of the ground hole, and the non-gas quantity flowing into the ground hole in unit time is equal to the non-gas quantity flowing out of the ground hole. And substituting the measured data and the known data into a source-division calculation model to obtain the flow of the gas flowing into the ground holes of the adjacent coal seam. According to the invention, carbon isotope test is not needed, so that the time for determining the gas extraction amount of the adjacent layer is effectively shortened, and the accuracy of the obtained gas extraction amount of the adjacent layer can be effectively ensured.
Description
Technical Field
The invention relates to a method for determining gas extraction amount of multiple coal beds, in particular to a method for determining gas extraction amount of adjacent layers based on ground drilling gas extraction.
Background
The ground drilling is one of the most common methods for extracting coal seam group gas from coal mines. For a mine mined by the protective layer, the gas extracted by the ground drilling is mainly formed by mixing the gas in the goaf of the coal bed and the pressure relief gas in the adjacent layer. The sub-source calculation for extracting multi-coal-bed gas from the ground drilling has important significance for the extraction effect investigation of the coal bed, especially the adjacent layers. At present, the source-dividing calculation of the ground drilling extraction mixed gas mainly adopts a carbon isotope test method, and the principle is that the carbon isotopes of different coal beds are obviously different (namely, the different carbon isotopes in the gas extracted by measuring the extraction drilling holes are different), and a quantitative analysis source calculation model of the gas sources of each coal bed is established based on the difference, so that the extraction gas quantity of the adjacent layers extracted by the ground drilling can be obtained and used for the research of the subsequent adjacent layers; although the mode can obtain the gas extraction amount of the adjacent layer, the method has the defects of long time required by test data, expensive equipment required by test isotope analysis, high popularization difficulty and the like.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a method for determining the gas extraction amount of the adjacent layer based on the gas extraction of the ground drilling without carbon isotope test, so that the time for determining the gas extraction amount of the adjacent layer is effectively shortened, the precision of the obtained gas extraction amount of the adjacent layer can be effectively ensured, and meanwhile, the method is simple in construction, low in required cost and convenient to use in various different coal beds.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: a method for determining the gas extraction amount of an adjacent layer based on the gas extraction of a ground drilling hole comprises the following specific steps:
A. drilling holes on the ground of the coal mine ground construction, enabling the holes to penetrate through the adjacent coal seam and extend into the roof of the coal seam to perform gas extraction; then around the surface boreholeConstructing a high-level drilling hole, so that the gas inlet end of the high-level drilling hole and the gas inlet end of the ground drilling hole are positioned at the same extraction layer; (because the two are positioned at the same extraction layer position, the extracted gas is diffused from the goaf to the same height of the top plate, so that the two can be approximately equal) so as to determine the concentration c of the gas extracted by the high-level drilling in the coal seam 0 Equal to the gas concentration c extracted from the coal seam by ground drilling 1 ；
B. Respectively carrying out gas extraction on the ground drilling hole and the high-level drilling hole, and respectively measuring the concentration c of the gas extracted by the high-level drilling hole 0 Concentration c of gas extracted from ground drilling 3 And the gas standard condition flow Q extracted from the ground drilling 3 ；
C. C, establishing a ground drilling extraction multi-coal-bed gas split-source calculation model 2 Concentration of gas entering the ground holes in the adjacent coal seam,%; q (Q) 1 Standard condition flow, m, for drilling holes on ground for gas inflow of coal seam 3 /min；Q 2 For the standard condition flow of the holes drilled on the ground adjacent to the gas inflow of the coal seam, m 3 A/min; setting the gas entering the ground drilling holes adjacent to the coal bed as pure gas; (because the adjacent layer is the original gas before pressure relief, is not disturbed by mining, and has no other gas entering, even when the coal layer is mined, the adjacent layer is the pressure relief gas to be flushed out and not other gas entering, so the extracted pressure relief gas can be determined to be pure gas)
Namely:
C 2 ＝100% (1)
according to the law of conservation of mass, the amount of pure gas in the gas flowing into the ground borehole is equal to the amount of pure gas in the gas flowing out of the ground borehole in unit time, namely:
Q 1 c 1 +Q 2 c 2 ＝Q 3 c 3 (2)
according to the law of conservation of mass, the amount of non-gas flowing into the ground borehole is equal to the amount of non-gas flowing out of the ground borehole in a unit time, namely:
Q 1 (1-c 1 )＝Q 3 (1-c 3 ) (3)
the system of equations consisting of equations (1) through (3) yields:
Q 2 ＝Q 3 c 3 -Q 1 c 1 (5)
the formula (4) and the formula (5) are ground drilling extraction multi-coal-bed gas split-source calculation models:
D. c, measuring the concentration c of gas extracted from the high-order drilling hole according to the step B 0 Concentration c of gas extracted from ground drilling 3 And the gas standard condition flow Q extracted from the ground drilling 3 The method comprises the steps of carrying out a first treatment on the surface of the And the concentration c of the gas extracted from the high-order drilling hole 0 Equal to the gas concentration c extracted from the coal seam by ground drilling 1 Substituting the calculation model of the ground drilling extraction multi-coal-bed gas source obtained in the step C to obtain the gas standard condition flow Q of the ground drilling holes into which the coal-bed gas is flushed 1 And gas standard condition flow Q of holes drilled on the ground adjacent to gas inflow of coal seam 2 ；
E. D, obtaining the gas standard condition flow Q of the holes on the ground where the gas of the adjacent coal seam is flushed 2 And the gas extraction amount of the adjacent coal seam in unit time is the gas extraction amount.
Compared with the prior art, because the gas concentration of the goaf extracted by the ground drilling hole cannot be directly measured, the invention constructs the high-position drilling holes around the ground drilling hole, and the gas inlet end of the high-position drilling hole is close to the gas inlet end of the ground drilling hole, so that the gas concentration extracted by the high-position drilling hole in the coal seam can be determined to be equivalent to the gas concentration extracted by the ground drilling hole in the coal seam; then, respectively extracting gas from the ground drilling hole and the high-level drilling hole, and measuring the concentration of the gas extracted from the high-level drilling hole, the concentration of the gas extracted from the ground drilling hole and the flow of the gas extracted from the ground drilling hole; and then constructing a ground drilling extraction multi-coal-bed gas source-dividing calculation model according to the mass conservation law, namely, the pure gas quantity flowing into the ground hole in unit time is equal to the pure gas quantity flowing out of the ground hole, and the non-gas quantity flowing into the ground hole in unit time is equal to the non-gas quantity flowing out of the ground hole. And substituting the measured data and the known data into a source-division calculation model to obtain the flow of the gas flowing into the ground holes of the adjacent coal seam. Therefore, the invention does not need to carry out carbon isotope test, thereby not only effectively shortening the time for determining the gas extraction amount of the adjacent layer, but also effectively ensuring the precision of the gas extraction amount of the adjacent layer, and simultaneously having simple construction, lower required cost and being convenient for the use and popularization of various different coal beds.
Drawings
Fig. 1 is a schematic view of the construction layout of the present invention.
Detailed Description
The present invention will be further described below.
As shown in fig. 1, the specific steps of the present invention are:
A. drilling holes on the ground of the coal mine ground construction, enabling the holes to penetrate through the adjacent coal seam and extend into the roof of the coal seam to perform gas extraction; then constructing high-level drilling holes around the ground drilling holes, so that the gas inlet ends of the high-level drilling holes and the gas inlet ends of the ground drilling holes are positioned at the same extraction layer; (because the two are positioned at the same extraction layer position, the extracted gas is diffused from the goaf to the same height of the top plate, so that the two can be approximately equal) so as to determine the concentration c of the gas extracted by the high-level drilling in the coal seam 0 Equal to the gas concentration c extracted from the coal seam by ground drilling 1 ；
B. Respectively carrying out gas extraction on the ground drilling hole and the high-level drilling hole, and respectively measuring the concentration c of the gas extracted by the high-level drilling hole 0 Concentration c of gas extracted from ground drilling 3 And the gas standard condition flow Q extracted from the ground drilling 3 ；
C. C, establishing a ground drilling extraction multi-coal-bed gas split-source calculation model 2 Concentration of gas entering the ground holes in the adjacent coal seam,%; q (Q) 1 Standard condition flow, m, for drilling holes on ground for gas inflow of coal seam 3 /min；Q 2 For the standard condition flow of the holes drilled on the ground adjacent to the gas inflow of the coal seam, m 3 A/min; setting the gas entering the ground drilling holes adjacent to the coal bed as pure gas; (since the gas is the original gas before the pressure relief of the adjacent layer, the adjacent layer is not disturbed by mining, and no other gas entersEven when mining coal seams, adjacent layers are pressure relief gas-surging and other gases are not entering, so the extracted pressure relief gas can be determined to be pure gas
Namely:
C 2 ＝100% (1)
according to the law of conservation of mass, the amount of pure gas in the gas flowing into the ground borehole is equal to the amount of pure gas in the gas flowing out of the ground borehole in unit time, namely:
Q 1 c 1 +Q 2 c 2 ＝Q 3 c 3 (2)
according to the law of conservation of mass, the amount of non-gas flowing into the ground borehole is equal to the amount of non-gas flowing out of the ground borehole in a unit time, namely:
Q 1 (1-c 1 )＝Q 3 (1-c 3 ) (3)
the system of equations consisting of equations (1) through (3) yields:
Q 2 ＝Q 3 c 3 -Q 1 c 1 (5)
the formula (4) and the formula (5) are ground drilling extraction multi-coal-bed gas split-source calculation models:
D. c, measuring the concentration c of gas extracted from the high-order drilling hole according to the step B 0 Concentration c of gas extracted from ground drilling 3 And the gas standard condition flow Q extracted from the ground drilling 3 The method comprises the steps of carrying out a first treatment on the surface of the And the concentration c of the gas extracted from the high-order drilling hole 0 Equal to the gas concentration c extracted from the coal seam by ground drilling 1 Substituting the calculation model of the ground drilling extraction multi-coal-bed gas source obtained in the step C to obtain the gas standard condition flow Q of the ground drilling holes into which the coal-bed gas is flushed 1 And gas standard condition flow Q of holes drilled on the ground adjacent to gas inflow of coal seam 2 ；
E. D, obtaining the gas standard condition flow Q of the holes on the ground where the gas of the adjacent coal seam is flushed 2 And the gas extraction amount of the adjacent coal seam in unit time is the gas extraction amount.
Claims (1)
1. The method for determining the gas extraction amount of the adjacent layer based on the gas extraction of the ground drilling is characterized by comprising the following specific steps:
A. drilling holes on the ground of the coal mine ground construction, enabling the holes to penetrate through the adjacent coal seam and extend into the roof of the coal seam to perform gas extraction; then constructing high-level drilling holes around the ground drilling holes, so that the gas inlet ends of the high-level drilling holes and the gas inlet ends of the ground drilling holes are positioned at the same extraction layer; thereby determining the concentration c of the gas extracted from the coal seam by the high-order drilling 0 Equal to the gas concentration c extracted from the coal seam by ground drilling 1 ；
B. Respectively carrying out gas extraction on the ground drilling hole and the high-level drilling hole, and respectively measuring the concentration c of the gas extracted by the high-level drilling hole 0 Concentration c of gas extracted from ground drilling 3 And the gas standard condition flow Q extracted from the ground drilling 3 ；
C. C, establishing a ground drilling extraction multi-coal-bed gas split-source calculation model 2 Concentration of gas entering the ground holes in the adjacent coal seam,%; q (Q) 1 Standard condition flow, m, for drilling holes on ground for gas inflow of coal seam 3 /min；Q 2 For the standard condition flow of the holes drilled on the ground adjacent to the gas inflow of the coal seam, m 3 A/min; setting the gas entering the ground drilling holes adjacent to the coal bed as pure gas;
namely:
C 2 ＝100％ (1)
according to the law of conservation of mass, the amount of pure gas in the gas flowing into the ground borehole is equal to the amount of pure gas in the gas flowing out of the ground borehole in unit time, namely:
Q 1 c 1 +Q 2 c 2 ＝Q 3 c 3 (2)
according to the law of conservation of mass, the amount of non-gas flowing into the ground borehole is equal to the amount of non-gas flowing out of the ground borehole in a unit time, namely:
Q 1 (1-c 1 )＝Q 3 (1-c 3 ) (3)
the system of equations consisting of equations (1) through (3) yields:
Q 2 ＝Q 3 c 3 -Q 1 c 1 (5)
the formula (4) and the formula (5) are ground drilling extraction multi-coal-bed gas split-source calculation models:
D. c, measuring the concentration c of gas extracted from the high-order drilling hole according to the step B 0 Concentration c of gas extracted from ground drilling 3 And the gas standard condition flow Q extracted from the ground drilling 3 The method comprises the steps of carrying out a first treatment on the surface of the And the concentration c of the gas extracted from the high-order drilling hole 0 Equal to the gas concentration c extracted from the coal seam by ground drilling 1 Substituting the calculation model of the ground drilling extraction multi-coal-bed gas source obtained in the step C to obtain the gas standard condition flow Q of the ground drilling holes into which the coal-bed gas is flushed 1 And gas standard condition flow Q of holes drilled on the ground adjacent to gas inflow of coal seam 2 ；
E. D, obtaining the gas standard condition flow Q of the holes on the ground where the gas of the adjacent coal seam is flushed 2 And the gas extraction amount of the adjacent coal seam in unit time is the gas extraction amount.
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