CN109578058B - Method for improving gas extraction concentration of extraction borehole through auxiliary drilling - Google Patents
Method for improving gas extraction concentration of extraction borehole through auxiliary drilling Download PDFInfo
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- CN109578058B CN109578058B CN201811501343.0A CN201811501343A CN109578058B CN 109578058 B CN109578058 B CN 109578058B CN 201811501343 A CN201811501343 A CN 201811501343A CN 109578058 B CN109578058 B CN 109578058B
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- E—FIXED CONSTRUCTIONS
- E21—EARTH 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 improving the gas extraction concentration of an extraction borehole through auxiliary drilling, which comprises the following steps: firstly, constructing a plurality of extraction drill holes on a roadway coal seam side by using a drilling machine with a small-diameter drill rod, and reaming on the basis of the drill holes by using the drilling machine with a large-diameter drill rod; secondly, after the drill hole is effectively plugged, primarily extracting gas in the drill hole by using a gas extraction pipe; when the gas extraction concentration is lower than 50%, further plugging the extraction drill hole and filling the hole sealing section with semi-fluid slurry; and thirdly, when the gas concentration is lower than 30%, constructing a plurality of auxiliary drill holes around the side-by-side extraction drill holes by using a drilling machine with a small-diameter drill rod, and plugging and grouting the auxiliary drill holes. The method can improve the utilization rate of the borehole extraction and the concentration of the gas extraction, shorten the effective extraction period, and take over the shortage phenomenon in the link of the extraction, and has simple operation and low cost.
Description
Technical Field
The invention relates to a gas extraction method, in particular to a method for improving the gas extraction concentration of an extraction borehole through auxiliary drilling, and belongs to the technical field of underground gas prevention and control.
Background
Along with the increase of the coal mining depth, the gas problem of the coal mine is increasingly serious, and particularly the gas treatment problem of a high-gas low-permeability coal seam is always seriously restricted on the safety production of the coal mine. Therefore, coal seam drilling gas extraction is widely used as an important measure for preventing and controlling gas outburst, but various problems of low extraction concentration, poor effect, short duration and the like exist in the gas extraction process.
In order to improve the coal seam drilling gas extraction effect, most outburst mines in China mostly adopt high-negative-pressure and high-flow extraction systems, but the gas leakage is increased and the gas extraction concentration is reduced, so that the effective gas extraction period is not shortened, the phenomenon of shortage in mining and replacement is relieved, the extraction concentration of a gas extraction pump station is lower than 30%, and the gas cannot be evacuated under the gas utilization conditions specified in coal mine safety regulations, and the environment is influenced.
And the coal seam drill holes cannot be comprehensively influenced by all factors of the ground stress during the gas extraction of the coal seam drill holes, so that the cracks around the coal seam drill holes are continuously developed, external air is easy to enter the extraction drill holes from the cracks under the action of extraction negative pressure, the gas extraction concentration is reduced, the effective extraction period of the extraction drill holes is shortened, and the utilization rate of the extraction drill holes is reduced.
Disclosure of Invention
In order to overcome various defects in the prior art, the invention provides the method for improving the gas extraction concentration of the extraction drill hole through the auxiliary drilling, which can improve the utilization rate and the gas extraction concentration of the drill hole, shorten the effective extraction period, relieve the phenomenon of insufficient mining and replacement, and has the advantages of simple operation and low cost.
In order to achieve the purpose, the invention provides a method for improving the gas extraction concentration of an extraction borehole through auxiliary drilling, which comprises the following steps:
firstly, constructing a plurality of extraction drill holes on a roadway coal seam side by using a drilling machine with a small-diameter drill rod, and reaming on the basis of the drill holes by using the drilling machine with a large-diameter drill rod;
secondly, after the drill hole is effectively plugged, primarily extracting gas in the drill hole by using a gas extraction pipe; when the gas extraction concentration is lower than 50%, further plugging the extraction drill hole and filling the hole sealing section with semi-fluid slurry;
and thirdly, when the gas concentration is lower than 30%, constructing a plurality of auxiliary drill holes around the side-by-side extraction drill holes by using a drilling machine with a small-diameter drill rod, and plugging and grouting the auxiliary drill holes.
The small-diameter drill rod is used for drilling holes, and then the large-diameter drill rod is used for expanding the holes, so that cracks around the drilled holes can be reduced; by constructing auxiliary drill holes around the extraction drill hole, fracture air leakage channels in the coal seam area related to the extraction drill hole are effectively communicated; semi-fluid slurry is injected into the closed section of the extraction drill hole and the auxiliary drill hole to plug peripheral cracks, and compared with the traditional solid hole sealing, the semi-fluid slurry has fluidity, so that the semi-fluid slurry can more easily enter the tiny cracks to plug tiny air leakage channels.
The distance L between the centers of all the extraction drill holes which are arranged side by side is 0.43H +/-L0H is the height of the coal seam, and the error is0And must not exceed 0.0625H.
Preferably, three auxiliary drill holes are uniformly distributed around each extraction drill hole, the auxiliary drill holes arranged between the two extraction drill holes are shared by the two extraction drill holes, the distances between the three auxiliary drill holes and the centers of the extraction drill holes are equal, and the included angle between each auxiliary drill hole corresponding to each extraction drill hole and the central connecting line of the extraction drill holes is 120 degrees.
Specifically, the distance l between the three auxiliary drill holes and the center of the extraction drill hole is 0.25H +/-l0H is the height of the coal seam, and the error is0And must not exceed 0.0625H.
The extraction drill hole and the auxiliary drill hole are not intersected in the axial direction, and the auxiliary drill hole depth is 1-3 m smaller than the extraction drill hole depth.
In the second step, during primary extraction, a gas extraction pipe with two ends bound with cotton cloth is used for plugging the drilled hole; and when the gas extraction concentration is lower than 50%, further plugging the extraction drill hole in a mode of installing polyurethane hole sealing bags at two ends.
The semifluid slurry comprises main materials, auxiliary materials and water, wherein the main materials are a mixture of sodium bentonite and kaolin, the auxiliary materials are a mixture of one or more than two of sodium silicate, lithium silicate, silicon dioxide and sodium chloride, and the mass ratio of the main materials to the auxiliary materials to the water is 1: 12-1: 8.
the mixed semi-fluid slurry is non-solidified inorganic semi-fluid hole sealing slurry and is always kept in a non-dehydration state during the whole plugging period, so that certain fluidity is maintained; the cemented fluid can also play a certain elastic supporting role on the wall of the drilled hole, effectively improves the compactness of the hole sealing section and reduces the seepage quantity of the continuously acting static water.
And after the corresponding auxiliary drill holes of the extraction drill holes are constructed, injecting semi-fluid slurry into the extraction drill holes and the auxiliary drill holes at the pressure of 2-3 MPa simultaneously to plug the cracks in the whole coal seam.
According to the method, firstly, a drilling machine with a small drill rod diameter is used for drilling holes, and then a drilling machine with a large drill rod diameter is used for reaming holes, so that the influence of stress change on the coal seam is reduced, and therefore, the generation of drilling cracks can be reduced to the greatest extent; all fracture air leakage channels in the circular coal seam area with each extraction drill hole as the center and the radius of H/2 are effectively plugged by constructing auxiliary drill holes with the depth smaller than that of the extraction drill holes on the periphery of the extraction drill holes; semi-fluid slurry is adopted for plugging, and certain pressure is maintained, so that self-plugging can be realized once new cracks develop and generate. The method greatly increases the gas extraction concentration, is particularly suitable for gas extraction at the later stage of drilling holes in coal seams arranged in a side-by-side mode, can extract more gas when the gas extraction concentration is low, effectively utilizes gas resources, promotes the safety production of coal mines, and reduces the emission of greenhouse gases.
Drawings
FIG. 1 is a schematic diagram of arrangement of extraction boreholes and auxiliary boreholes in accordance with the present invention;
in the figure: 1. and (3) auxiliary drilling, 2, extraction drilling, and 3, coal seam of a coal roadway.
Detailed Description
The invention is described in detail below with reference to the figures and the specific embodiments.
As shown in fig. 1, a method for improving gas extraction concentration of an extraction borehole through auxiliary drilling comprises the following steps:
firstly, constructing a plurality of extraction drill holes on a roadway coal seam side by using a drill with a drill rod of 30mm, and reaming on the basis of the drill hole of 30mm by using the drill with the drill rod of 80 mm; the distance L between the centers of the extraction boreholes 2 arranged side by side is 0.43H +/-L0H is the height of the coal seam, and the error is0Not more than 0.0625H;
secondly, plugging the drilled hole by using a gas extraction pipe with two ends bound with cotton cloth, and performing primary extraction on gas in the drilled hole by using the gas extraction pipe; when the gas extraction concentration is lower than 50%, further plugging the extraction drill hole in a mode of mounting polyurethane hole sealing bags at two ends, and filling the hole sealing section with semi-fluid slurry;
thirdly, when the gas concentration is lower than 30%, constructing a plurality of auxiliary drill holes around the side-by-side extraction drill holes by using a drill with a drill rod of 30mm, wherein the extraction drill hole 2 does not intersect with the auxiliary drill hole 1 in the axial direction, and the depth of the auxiliary drill hole 1 is 1-3 m smaller than that of the extraction drill hole 2;
three auxiliary drill holes 1 are uniformly distributed around each extraction drill hole 2, the auxiliary drill holes 1 arranged between the two extraction drill holes 2 are shared by the two extraction drill holes 2, the distances between the three auxiliary drill holes 1 and the centers of the extraction drill holes 2 are equal, and the included angle between the central connecting line of each auxiliary drill hole 1 corresponding to each extraction drill hole 2 and the extraction drill hole 2 is 120 degrees; the distance l between the three auxiliary drill holes 1 and the center of the extraction drill hole 2 is 0.25H +/-l0H is the height of the coal seam, and the error is0Not more than 0.0625H;
after the corresponding auxiliary drill hole 1 of the extraction drill hole is constructed, semi-fluid slurry is simultaneously injected into the extraction drill hole 2 and the auxiliary drill hole 1 at the pressure of 2-3 MPa to plug the crack in the whole coal seam.
The small-diameter drill rod is used for drilling holes, and then the large-diameter drill rod is used for expanding the holes, so that cracks around the drilled holes can be reduced; by constructing auxiliary drill holes around the extraction drill hole, fracture air leakage channels in the coal seam area related to the extraction drill hole are effectively communicated; semi-fluid slurry is injected into the closed section of the extraction drill hole and the auxiliary drill hole to plug peripheral cracks, and compared with the traditional solid hole sealing, the semi-fluid slurry has fluidity, so that the semi-fluid slurry can more easily enter the tiny cracks to plug tiny air leakage channels.
The semifluid slurry comprises main materials, auxiliary materials and water, wherein the main materials are a mixture of sodium bentonite and kaolin, the auxiliary materials are a mixture of one or more than two of sodium silicate, lithium silicate, silicon dioxide and sodium chloride, and the mass ratio of the main materials to the auxiliary materials to the water is 1: 12-1: 8.
the mixed semi-fluid slurry is non-solidified inorganic semi-fluid hole sealing slurry and is always kept in a non-dehydration state during the whole plugging period, so that certain fluidity is maintained; the cemented fluid can also play a certain elastic supporting role on the wall of the drilled hole, effectively improves the compactness of the hole sealing section and reduces the seepage quantity of the continuously acting static water.
Claims (4)
1. A method for improving the gas extraction concentration of an extraction borehole through auxiliary drilling comprises the following steps:
firstly, constructing a plurality of extraction drill holes (2) on a roadway coal seam side by adopting a drilling machine with a small-diameter drill rod, and then reaming on the basis of the extraction drill holes (2) by utilizing a drilling machine with a large-diameter drill rod;
secondly, plugging the extraction drill hole (2) by using a gas extraction pipe with two ends bound with cotton cloth, and primarily extracting gas in the extraction drill hole (2) by using the gas extraction pipe; when the gas extraction concentration is lower than 50%, further plugging the extraction drill hole (2) in a mode of mounting polyurethane hole sealing bags at two ends, and filling the hole sealing section with semi-fluid slurry; the semifluid slurry comprises main materials, auxiliary materials and water, wherein the main materials are a mixture of sodium bentonite and kaolin, the auxiliary materials are a mixture of one or more than two of sodium silicate, lithium silicate, silicon dioxide and sodium chloride, and the mass ratio of the main materials to the auxiliary materials to the water is 1: 12～1：8；
Thirdly, when the gas concentration is lower than 30%, constructing a plurality of auxiliary drill holes (1) around the side-by-side extraction drill hole (2) by using a drill machine with a small-diameter drill rod, and using 2～Injecting semifluid slurry into the extraction drill hole (2) and the auxiliary drill hole (1) at the same time under the pressure of 3MPa to plug the cracks in the whole coal seam;
three auxiliary drill holes (1) are uniformly distributed around each extraction drill hole (2), the auxiliary drill holes (1) arranged between the two extraction drill holes (2) are shared by the two extraction drill holes (2), the distances between the three auxiliary drill holes (1) and the centers of the extraction drill holes (2) are equal, and the included angle between the center connecting lines of the auxiliary drill holes (1) and the extraction drill holes (2) corresponding to each extraction drill hole (2) is 120 degrees.
2. The method for increasing the gas extraction concentration of an extraction borehole through an auxiliary borehole according to claim 1, characterized in that the distance L between the centers of the side-by-side extraction boreholes (2) is 0.43H ± L0H is the height of the coal seam, and the error is0And must not exceed 0.0625H.
3. The method for increasing the gas extraction concentration of an extraction borehole through an auxiliary borehole according to claim 1, characterized in that the distance l between the three auxiliary boreholes (1) and the center of the extraction borehole (2) is 0.25H ± l0H is the height of the coal seam, and the error is0And must not exceed 0.0625H.
4. The method for improving the gas extraction concentration of the extraction borehole through the auxiliary borehole according to claim 3, characterized in that the extraction borehole (2) does not intersect with the auxiliary borehole (1) in the axial direction, and the depth of the auxiliary borehole (1) is less than the depth 1 of the extraction borehole (2)～3m。
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| CN111173556B (en) * | 2020-01-13 | 2022-04-05 | 中煤平朔集团有限公司 | Method for preventing borehole collapse during large-diameter borehole replacement traversing |
| CN112627766B (en) * | 2020-12-23 | 2022-12-27 | 中煤科工集团重庆研究院有限公司 | External injection compensation type hole sealing method for gas extraction drill hole |
| CN113464122A (en) * | 2021-06-23 | 2021-10-01 | 中国矿业大学 | Method for improving gas pressure determination accuracy through auxiliary drilling |
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| CN102434194A (en) * | 2011-09-30 | 2012-05-02 | 神华集团有限责任公司 | Gas drainage drill hole structure formed in coal layer and method for fabricating same |
| CN105114030A (en) * | 2015-08-20 | 2015-12-02 | 中国矿业大学 | Gas extraction drilling non-solidification constant-pressure slurry hole sealing method |
| CN108590742A (en) * | 2018-05-10 | 2018-09-28 | 西安科技大学 | Reducing reaming improves the mine gas extraction system and method for gas extraction concentration |
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| US6280000B1 (en) * | 1998-11-20 | 2001-08-28 | Joseph A. Zupanick | Method for production of gas from a coal seam using intersecting well bores |
| CN104975868A (en) * | 2015-06-13 | 2015-10-14 | 山西晋城无烟煤矿业集团有限责任公司 | Top plate high-position boring large-diameter long-drill-hole gas extraction method based on directional drilling |
| CN106220121B (en) * | 2016-07-21 | 2018-06-08 | 中煤科工集团重庆研究院有限公司 | A kind of parent's coal base mash gas pumping drilling sealing material and its application method |
| CN108316964A (en) * | 2018-02-01 | 2018-07-24 | 西安科技大学 | A kind of low air permeability coal seam pressure relief gas pumping mining method |
| CN108150127B (en) * | 2018-02-13 | 2024-03-19 | 安徽佳泰矿业科技有限公司 | Hole sealing device and hole sealing method for mine gas extraction drilling |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102434194A (en) * | 2011-09-30 | 2012-05-02 | 神华集团有限责任公司 | Gas drainage drill hole structure formed in coal layer and method for fabricating same |
| CN105114030A (en) * | 2015-08-20 | 2015-12-02 | 中国矿业大学 | Gas extraction drilling non-solidification constant-pressure slurry hole sealing method |
| CN108590742A (en) * | 2018-05-10 | 2018-09-28 | 西安科技大学 | Reducing reaming improves the mine gas extraction system and method for gas extraction concentration |
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