CN107130997B - Technical method for mining bedding drilling and extracting pressure relief gas on working face of unequal length protective layer - Google Patents
Technical method for mining bedding drilling and extracting pressure relief gas on working face of unequal length protective layer Download PDFInfo
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- CN107130997B CN107130997B CN201710504674.9A CN201710504674A CN107130997B CN 107130997 B CN107130997 B CN 107130997B CN 201710504674 A CN201710504674 A CN 201710504674A CN 107130997 B CN107130997 B CN 107130997B
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- permeability
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- 238000005553 drilling Methods 0.000 title claims abstract description 26
- 238000000034 method Methods 0.000 title claims abstract description 17
- 238000005065 mining Methods 0.000 title claims description 33
- 239000011241 protective layer Substances 0.000 title claims description 14
- 239000003245 coal Substances 0.000 claims abstract description 35
- 230000035699 permeability Effects 0.000 claims abstract description 20
- 238000009828 non-uniform distribution Methods 0.000 claims abstract description 10
- 239000010410 layer Substances 0.000 claims description 60
- 238000000605 extraction Methods 0.000 claims description 19
- 230000035515 penetration Effects 0.000 claims description 7
- 238000009826 distribution Methods 0.000 claims description 6
- 230000000694 effects Effects 0.000 claims description 3
- 239000011435 rock Substances 0.000 claims description 3
- 238000003825 pressing Methods 0.000 claims description 2
- 238000010276 construction Methods 0.000 abstract description 4
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004031 devitrification Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- 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
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/30—Specific pattern of wells, e.g. optimising the spacing of wells
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- Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- Drilling And Exploitation, And Mining Machines And Methods (AREA)
Abstract
On the basis of obtaining the non-uniform distribution characteristics of the stress and permeability of the working surface of the protected layer, the working surface of the protected layer is divided into three areas, namely a pressure relief area (an anti-reflection area), a stress concentration area (a permeability reduction area) and an original stress area (an original permeability area), so that a bedding drilling hole arrangement mode with reasonable spacing and length is provided, bedding drilling holes are constructed in lanes on two sides of the working surface of the protected layer, and the pressure relief gas of the working surface of the protected layer is extracted. The technical method is simple and easy to implement, has strong reliability, less drilling construction amount and low cost, greatly improves the working efficiency, and provides technical guarantee for eliminating the coal and gas outburst risk of the working face of the protected layer.
Description
Technical Field
The invention relates to a technical method for extracting pressure relief gas in a coal mine, in particular to a technical method for extracting pressure relief gas from a bedding drill hole in the mining of a working face with unequal length protective layers, which is suitable for extracting the pressure relief gas under the condition that the stress and permeability of the working face of a protected layer in the coal mine are unevenly distributed.
Technical Field
Coal is the main energy source of China, and the great amount of coal mining causes the increase of the coal mining depth year by year. Along with the increase of the mining depth, the gas pressure and the gas content of the coal bed are gradually increased, the gas emission amount is continuously increased, the coal and gas outburst disasters are increasingly frequent and serious, and the threat to the coal mine safety production is also increased. Meanwhile, the permeability coefficient of most coal beds is only 10 -3 ～1.0m 2 /(MPa 2 D), resulting in poor gas extraction. Long-term theoretical researchMining practices of outburst dangerous coal seams prove that mining protective layers are regional measures for effectively preventing coal and gas outburst. Therefore, under the prior art condition, the mining protection layer is combined with the reinforced gas extraction to become a preferred technology for effectively preventing and treating the coal and gas outburst, and the mining protection layer has important practical significance for guaranteeing the safe and efficient mining of the coal and gas outburst dangerous coal seam.
However, under the influence of mining planning and face layout, the trend and trend length of the upper protective layer face are generally difficult to be consistent with those of the protected layer, i.e. the protective layer face and the protected layer face are not equally long and equally wide. When the trend and the trend length of the working face of the upper protective layer are smaller than those of the protective layer, the pressure relief area of the underlying protective layer is limited, and the reserved coal pillar of the upper protective layer further aggravates the stress concentration degree of the underlying protective layer. Therefore, how to optimize the hole distribution mode of the pressure relief gas extraction drilling holes ensures that the working surface of the protected layer thoroughly eliminates the danger of coal and gas outburst, reduces the gas treatment cost as much as possible, and is a difficult problem in front of field engineering technicians.
Object of the Invention
The invention aims to provide a technical method for extracting the pressure relief gas of the protected layer by sequential drilling, which has the advantages of simple and easy method, strong technical reliability and low construction cost under the condition that the pressure relief area of the protected layer is limited.
Technical proposal
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
a. according to the geological conditions of the coal mine, the occurrence rules of the coal seam and the mining conditions of the coal face, comprehensively adopting a mine pressure and rock stratum control theory and FLAC3D numerical simulation software, analyzing the mining stress space-time evolution rules of the working face of the protected layer in the mining process of the working face of the protected layer, and obtaining the non-uniform distribution characteristics of the mining stress;
b. dividing the working surface of the protected layer into a pressure relief area, a stress concentration area and an original stress area from the plane according to the mining stress non-uniform distribution characteristic of the working surface of the protected layer;
c. analyzing a functional relation K=f (sigma) of mining stress sigma and coal seam permeability K according to a seepage mechanics theory, and further obtaining the permeability non-uniform distribution characteristic of the working face of the protected layer;
d. dividing the working surface of the protected layer into an anti-reflection area, an anti-reflection area and an original penetration area from the plane according to the characteristic of non-uniform permeability distribution of the working surface of the protected layer, wherein the pressure relief area and the anti-reflection area, the stress concentration area and the anti-reflection area and the original stress area and the original penetration area are respectively completely overlapped according to the functional relation of the mining stress and the permeability;
e. when adopting the bedding drill holes to extract the pressure-relief gas of the working surface of the protected layer, analyzing the influence of bedding drill hole spacing and extraction time on the gas extraction effects of different areas of the working surface of the protected layer, and obtaining the effective extraction radius of the bedding drill holes of different areas of the working surface of the protected layer under the condition of a certain extraction time;
f. according to the effective extraction radius of the bedding boreholes, determining reasonable spacing of bedding boreholes in different areas of the working surface of the protected layer, wherein the bedding boreholes for extracting gas in the anti-reflection area are large in length and spacing, and the bedding boreholes are called bedding long boreholes; the length and the interval of the bedding boreholes for extracting the gas in the permeability-reducing area are smaller, and the bedding boreholes are called bedding short boreholes; the gas in the permeability-reducing area is extracted while the gas in the permeability-reducing area is extracted through the long-layer drilling holes, and the arrangement mode of the drilling holes is shown as the alternate arrangement of the long drilling holes and the short drilling holes on a plane;
g. and respectively constructing bedding boreholes with reasonable spacing and length on two side tunnels of the working face of the protected layer, wherein stubble pressing of bedding long boreholes is at least 1m, and extracting pressure relief gas of the working face of the protected layer until the working face of the protected layer eliminates the risk of coal and gas outburst.
The invention has the beneficial effects that:
(1) According to the partition characteristics of stress and permeability of the working surface of the protected layer, the bedding drill holes with different intervals and lengths are constructed to extract the pressure relief gas of the protected layer, so that the working surface of the protected layer is ensured to thoroughly eliminate the outburst risk of coal and gas, and the method is simple and easy to implement and has strong technical reliability;
(2) According to the invention, the pressure relief gas extraction drilling and hole distribution mode is optimized, so that the drilling construction amount is reduced, the construction cost is reduced, and the working efficiency is greatly improved.
Drawings
Fig. 1 is a schematic perspective view of the technical method of the present invention.
Fig. 2 is a schematic plan view of the technical method of the present invention.
In the figure: 1-a protective layer working surface; 2-a working surface of the protected layer; 3-pressure relief zone (anti-reflection zone); 4-stress concentration zone (devitrification zone); 5-original stress zone (original penetration zone); 6, drilling along the layer length; 7-short and smooth drilling.
Detailed Description
Embodiments of the present invention are further described below with reference to fig. 1 and 2:
the technical method of the invention relates to a reasonable hole distribution mode for sequential layer drilling at positions of different areas of a protected layer, which comprises a protected layer working surface 1, a protected layer working surface 2, a pressure relief area (anti-reflection area) 3, a stress concentration area (anti-reflection area) 4, an original stress area (original permeability) 5, sequential layer long drilling holes 6 and sequential layer short drilling holes 7, and comprises the following specific operation steps:
a. according to the geological conditions of a coal mine, occurrence rules of a coal seam and mining conditions of a coal face, comprehensively adopting a mine pressure and rock stratum control theory and FLAC3D numerical simulation software, analyzing the mining stress space-time evolution rules of a protected layer working face 2 in the mining process of a protected layer working face 1, and obtaining mining stress non-uniform distribution characteristics;
b. dividing the working surface 2 to be protected into a pressure relief area 3, a stress concentration area 4 and an original stress area 5 from the plane according to the mining stress non-uniform distribution characteristic of the working surface 2 to be protected;
c. analyzing a functional relation K=f (sigma) of the mining stress sigma and the coal seam permeability K according to a seepage mechanics theory, and further obtaining the permeability non-uniform distribution characteristic of the working face 2 of the protected layer;
d. dividing the working surface 2 of the protected layer into an anti-reflection area 3, an anti-reflection area 4 and an original penetration area 5 from the plane according to the characteristic of non-uniform permeability distribution of the working surface 2 of the protected layer, wherein the pressure relief area and the anti-reflection area, the stress concentration area and the anti-reflection area and the original stress area and the original penetration area are respectively completely overlapped according to the functional relation of the mining stress and the permeability;
e. when adopting the bedding boreholes 6 and 7 to extract the pressure relief gas of the working surface 2 of the protected layer, analyzing the influence of bedding borehole spacing and extraction time on the gas extraction effect of different areas of the working surface 2 of the protected layer, and obtaining the effective extraction radius of the bedding boreholes of different areas of the working surface 2 of the protected layer under the condition of a certain extraction time;
f. according to the effective extraction radius of the bedding boreholes 6 and 7, determining reasonable spacing of bedding boreholes in different areas of the working face 2 of the protected layer, wherein the bedding boreholes for extracting gas in the anti-reflection area are large in length and spacing, and the method is called bedding long borehole 6; the length and the interval of the bedding boreholes for extracting the gas in the permeability-reducing area are smaller, and the bedding boreholes are called bedding short boreholes 7; the bedding long drilling holes 6 are used for extracting gas in the permeability-reducing area while extracting gas in the permeability-reducing area, and the arrangement mode of the drilling holes is shown as long and short drilling holes alternately arranged on a plane;
g. and respectively constructing bedding boreholes 6 and 7 with reasonable spacing and length on the two side roadways of the working face 2 to be protected, wherein the bedding long borehole 6 is stubble-pressed for at least 1m, and extracting the pressure relief gas of the working face 2 to be protected until the working face 2 to be protected eliminates the coal and gas outburst risk.
Claims (1)
1. A technical method for extracting pressure relief gas of a protected layer by bedding drilling after mining of a working face of a non-equilong protected layer is characterized by comprising the following steps:
a. according to the geological conditions of a coal mine, occurrence rules of a coal seam and mining conditions of a coal face, in combination with factors such as coal seam air permeability, reserved coal pillars of an upper protective layer and the like, comprehensively adopting mine pressure and rock stratum control theory and FLAC3D numerical simulation software, analyzing the mining stress space-time evolution rules of the working face of a protected layer in the mining process of the working face of the protective layer, and obtaining mining stress non-uniform distribution characteristics;
b. dividing the working surface of the protected layer into a pressure relief area, a stress concentration area and an original stress area from the plane according to the mining stress non-uniform distribution characteristic of the working surface of the protected layer;
c. analyzing a functional relation K=f (sigma) of mining stress sigma and coal seam permeability K according to a seepage mechanics theory, and further obtaining the permeability non-uniform distribution characteristic of the working face of the protected layer;
d. dividing the working surface of the protected layer into an anti-reflection area, an anti-reflection area and an original penetration area from the plane according to the characteristic of non-uniform permeability distribution of the working surface of the protected layer, wherein the pressure relief area and the anti-reflection area, the stress concentration area and the anti-reflection area and the original stress area and the original penetration area are respectively completely overlapped according to the functional relation of the mining stress and the permeability;
e. when adopting the bedding drill holes to extract the pressure-relief gas of the working surface of the protected layer, analyzing the influence of bedding drill hole spacing and extraction time on the gas extraction effects of different areas of the working surface of the protected layer, and obtaining the effective extraction radius of the bedding drill holes of different areas of the working surface of the protected layer under the condition of a certain extraction time;
f. according to the effective extraction radius of the bedding boreholes in different areas of the working face of the protected layer, determining the reasonable spacing of the bedding boreholes in different areas of the working face of the protected layer, wherein the bedding boreholes for extracting the gas of the anti-reflection area are large in length and spacing, and the method is called bedding long borehole; the length and the interval of the bedding boreholes for extracting the gas in the permeability-reducing area are smaller, and the bedding boreholes are called bedding short boreholes; the gas in the permeability-reducing area is extracted while the gas in the permeability-reducing area is extracted through the long-layer drilling holes, and the arrangement mode of the drilling holes is shown as the alternate arrangement of the long drilling holes and the short drilling holes on a plane;
g. and respectively constructing bedding boreholes with reasonable spacing and length on two side tunnels of the working face of the protected layer, wherein stubble pressing of bedding long boreholes is at least 1m, and extracting pressure relief gas of the working face of the protected layer until the working face of the protected layer eliminates the risk of coal and gas outburst.
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| CN201710504674.9A CN107130997B (en) | 2017-06-28 | 2017-06-28 | Technical method for mining bedding drilling and extracting pressure relief gas on working face of unequal length protective layer |
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Families Citing this family (4)
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| CN110685732B (en) * | 2019-09-29 | 2021-06-15 | 华北科技学院 | Coal seam drilling gas extraction method based on extraction pipeline valve control |
| CN110836114B (en) * | 2019-11-21 | 2021-07-30 | 中煤科工集团重庆研究院有限公司 | Method for treating coal mine rock burst and gas composite disaster |
| CN113586133A (en) * | 2021-09-08 | 2021-11-02 | 中煤科工集团重庆研究院有限公司 | Method for extracting pressure-relief gas from adjacent layer mined by upper protection layer of close-distance thin coal seam group |
| CN115030702B (en) * | 2022-06-16 | 2023-05-12 | 中国矿业大学 | Accurate pressure relief and permeability increase method for gas unsteady occurrence coal seam |
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