CN107313743B - Method for repairing weak zone of coal seam floor water-resisting layer by utilizing coal seam gas well - Google Patents

Method for repairing weak zone of coal seam floor water-resisting layer by utilizing coal seam gas well Download PDF

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Publication number
CN107313743B
CN107313743B CN201710535523.XA CN201710535523A CN107313743B CN 107313743 B CN107313743 B CN 107313743B CN 201710535523 A CN201710535523 A CN 201710535523A CN 107313743 B CN107313743 B CN 107313743B
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grouting
water
hole
coal bed
coal
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CN107313743A (en
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孟召平
姚爱军
白建平
田永东
李超
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China University of Mining and Technology Beijing CUMTB
Shanxi Jincheng Anthracite Mining Group Co Ltd
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China University of Mining and Technology Beijing CUMTB
Shanxi Jincheng Anthracite Mining Group Co Ltd
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    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21BEARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B33/00Sealing or packing boreholes or wells
    • E21B33/10Sealing or packing boreholes or wells in the borehole
    • E21B33/13Methods or devices for cementing, for plugging holes, crevices, or the like

Abstract

The invention belongs to the technical field of coal and coalbed methane resource co-mining, and provides a method for repairing a weak zone of a coalbed methane well on a coalbed methane floor by using a coalbed methane well in order to fully utilize grouting, reinforcing and repairing the weak zone of the coalbed methane floor water-stop layer to be mined; and then high-pressure grouting is carried out by extending the drilling hole of the grouting repairing section, and a water guiding crack in the water-resisting layer of the coal seam floor is filled, so that the strength of the weak water-resisting layer of the coal seam floor is reinforced, the water guiding crack is sealed, a water source supply channel is cut off, and the possibility of water inrush of the coal seam floor is reduced.

Description

Method for repairing weak zone of coal seam floor water-resisting layer by utilizing coal seam gas well
Technical Field
The invention belongs to the technical field of coal and coalbed methane resource co-mining, and particularly relates to a method for repairing a weak zone of a coal bed bottom plate water-resisting layer by utilizing a coalbed methane well.
Background
Along with the expansion of the development scale of the coal bed gas, the influence of the coal bed gas development on future coal exploitation is increasingly prominent, and if a sleeve is left in a ground coal bed gas extraction well, the coal exploitation is not facilitated; permeability-increasing measures such as ground drilling and hydraulic fracturing damage the conditions of the top and bottom plates of the coal seam, are easy to communicate with a water-bearing stratum, and bring potential safety hazards to future coal mining. The coal bed gas development vertical well is generally completed 40-50m below a coal bed bottom plate, the coal bed gas drilling well has the disturbance and damage effects on the coal bed bottom plate, and after the coal bed gas is drained and mined, the mining effect of coal causes secondary damage to the bottom plate. If the interlayer spacing between the coal bed and the aquifer is small, the danger of water inrush from the bottom plate exists in coal mining after coal bed gas development.
For example, in a Zhuang-land in the mine area of the Jincheng in the south of Qin basin in Shanxi, coal bed gas is drilled to the lower part of about 40-50m of the 15# coal of the Taiyuan group of the charcoal system. According to geological data, the water level elevation of the Ordovician limestone aquifer in the area is 454.70 m-535 m; the mining elevation of the coal seam is 420-730 m, and the water level of the Ordovician limestone aquifer is 0-112 m higher than the bottom plate of each coal seam. In this case, the coal bed gas well drilling has the possibility of conducting the Ordovician water. At present, Shanxi blue flame coal bed gas company has constructed the remaining 260 coal bed gas wells in the range of the banked mine in the mine area of Jincheng, and the development of the coal bed gas in the area adopts a combined mining mode, namely 3#, 9# and 15# coal are used for mining the coal bed gas simultaneously. Production practices show that the liquid level of some wells cannot be lowered in a late time and is always maintained above a No. 3 coal seam, the liquid level is difficult to lower, communication with Ordovician limestone aquifer water at the bottom of the coal seam is possible, and water inrush hidden danger is possible in the coal mining process after coal bed gas development.
Therefore, the existing coal bed gas well is fully utilized, the reinforcement and repair are carried out on the weak area of the water-resisting layer of the coal bed bottom plate, the production cost can be reduced, the water inrush of the bottom plate can be effectively prevented, and the safety guarantee capability of future coal mining is remarkably improved.
Disclosure of Invention
The key technical problems to be solved by the invention are as follows:
(1) how to fully utilize the existing abandoned coal bed gas well to carry out grouting reinforcement and repair on a weak zone of a water-resisting layer of a coal bed bottom plate to be exploited. Obviously, the grouting reinforcement treatment is carried out on the coal seam floor water-resisting layer belt, the rock stratum strength of the coal seam floor structural crushing area and the weak water-resisting layer belt can be increased, the damage of mining pressure and bearing water pressure to the floor water-resisting layer is reduced, and the purpose of safe production is achieved. Under the general condition, underground drilling grouting reinforcement and ground drilling grouting reinforcement are commonly adopted in engineering, rotary drilling is adopted in the underground bottom plate grouting reinforcement technology, the inclination angle of a drilled hole is fixed, the formed hole is also a straight hole, hole traces are not easy to control, the grouting section is short, the grouting effect is not good, the utilization rate of the drilled hole is low, a temporary grouting station is arranged underground, manpower and material resources are consumed, and the mechanization degree is not high. The ground drilling grouting has relatively good working environment and greatly improved working efficiency, but can obviously increase the drilling engineering cost and prolong the construction period. Therefore, the coal bed gas well is fully utilized for grouting, the drilling cost is reduced, the grouting efficiency and quality are improved, the versatility of the coal bed gas well is exerted, and the high utilization rate of the coal bed gas well is realized.
(2) The range and the quality control technology for grouting, reinforcing and repairing the weak zone of the water-resisting layer of the coal seam floor 4 by using the coal seam gas well. The coal bed gas well is a drilled well which is excavated according to the distribution characteristics of coal bed gas resources, and the well spacing and the layout of the drilled well cannot cover a weak area of a water-resisting layer of a coal bed bottom plate, so that measures need to be taken in the aspects of a drilling extension section 16, grouting pressure, grouting materials and the like of the coal bed gas well, the grouting reinforcement and repair range and quality are strictly controlled, the strength of the coal bed bottom plate 4 is furthest repaired and enhanced, and the water conductivity of rock mass of the coal bed bottom plate 4 is reduced.
The invention specifically adopts the following technical scheme:
a method for repairing a weak zone of a water-resisting layer of a coal bed bottom plate by using a coal bed gas well is characterized in that the water-resisting layer of the coal bed bottom plate is reinforced by using a waste coal bed gas well, and a hole of an extension grouting repairing section of a downward extension section of the coal bed gas well is formed by drilling at the bottom of the waste coal bed gas well; and then high-pressure grouting is carried out by extending the drilling hole of the grouting repairing section, and a water guiding crack in the water-resisting layer of the coal seam floor is filled, so that the strength of the weak water-resisting layer of the coal seam floor is reinforced, the water guiding crack is sealed, a water source supply channel is cut off, and the possibility of water inrush of the coal seam floor is reduced.
The specific construction process comprises the following steps:
1) selecting a coal bed gas well, a drilling machine and construction materials for preparation;
2) a pneumatic down-the-hole hammer is put along the coal bed gas well to drill a drill hole in the extension grouting section of the coal bed gas well, when the drill hole in the extension grouting repair section is constructed, the drill hole is continuously drilled from the bottom of a two-cut drill hole or a three-cut drill hole of the original abandoned coal bed gas well, and a water flowing crack of the coal bed bottom plate passes through a water-resisting layer of the coal bed bottom plate to the bottom of the hole to form a drill hole in the extension grouting repair section;
3) performing a water pressure test in the well, and measuring the permeability of the drill hole of the extension grouting section;
4) a high-pressure grouting device is put into the bottom of the hole, a grout stop plug is arranged at the top of the drilled hole of the extension grouting repairing section, and high-pressure grouting is carried out in the hole;
5) after grouting, waiting for solidification;
6) adopting a pneumatic down-the-hole hammer to carry out hole sweeping on the drill hole of the extension grouting repairing section and drill the drill hole to the bottom of the hole;
7) performing a pressurized water test in the well again, measuring the permeability of the drill hole of the extension grouting section, and repeating the steps 4) -5) if the permeability does not meet the requirement; if the permeability meets the requirement, stopping repairing and grouting, and filling the coal bed gas well with cement soil slurry to a position above the coal bed top plate to form plugging slurry;
8) and (4) sealing and protecting the wellhead of the coal-bed gas well.
And if the sectional grouting is carried out, starting grouting from the bottom of the hole, finishing grouting at the lower part, then carrying out upper grouting, and repeating the steps 4) -5) until the whole drilled hole of the extension grouting repair section is grouted and reinforced and is in waiting for setting.
And the final hole depth of the drill hole of the extension grouting repairing section is 40-60 m below the coal seam floor or the depth from the drill hole to the water-bearing stratum top plate.
The grouting slurry adopts pure cement slurry, and the water-cement ratio is 1: 1.6, density 1.65t/m3
The final pressure of the grouting is 6-10 MPa.
After the coal bed gas well is drained and mined, the pipe well of the coal bed gas well is reformed and reused, holes are drilled continuously at the bottom of the holes (the bottoms of the two-way drilled holes or the three-way drilled holes), water flowing cracks penetrate through the coal bed bottom plate until the water flowing cracks are close to a water-bearing layer, and drilled holes of an extension grouting repairing section are formed. The method has the advantages that the weak area and the water guide cracks of the coal seam floor are reinforced by grouting in a full-hole or sectional high-pressure grouting mode through the extension grouting repairing section drill holes, so that the water permeability of the water guide cracks is gradually reduced, a water source supply channel is cut off, the mechanical strength of the coal seam floor is increased, and the water inrush prevention capacity of the coal seam floor is greatly improved.
Drawings
FIG. 1 is a sectional view of a grouted repaired borehole (lower grout);
FIG. 2 is a sectional view of a grouted repaired borehole (top grouting);
FIG. 3 is a sectional view of a grouting repaired borehole (downhole backfill);
in the figure: 1. a fourth series; 2. an overlying rock formation of the coal seam; 3. a coal seam; 4. a coal seam floor water barrier; 5. an aqueous layer; 6. an orifice; 7. drilling a hole; 8. a surface casing; 9. outer layer is sleeved with shell material; 10. secondly, drilling a hole; 11. a technical sleeve; 12. grouting outside the technical casing; 13. three-opening drill holes; 14. producing a sleeve; 15. producing casing outer grouting body; 16. drilling a section for extending, grouting and repairing; 17. a grout stopping plug; 18. water flowing cracks of a coal seam floor; 19. bottom of the hole; 20. grouting; 21. and (5) plugging the slurry.
Detailed Description
The embodiments of the invention will be further explained with reference to the accompanying drawings:
aiming at the recycling problem of the waste coal-bed gas well, the invention solves the technical problem of repairing and reinforcing the weak area of the water-resisting layer of the coal-bed bottom plate by using the waste coal-bed gas well based on the auxiliary technologies of drilling of the extension section of the grouting hole at the bottom of the coal-bed gas well, pressure grouting of the extension section, filling of the coal-bed gas well and the like. The method is technically characterized in that a pneumatic down-the-hole hammer is adopted to continuously drill (the diameter of a drill hole is phi 94-phi 75) at the bottom of a waste coal-bed gas well (the bottom of a second-cut drill hole 10 or a third-cut drill hole 13) to form a grouting hole 16 of a downward extending section of the coal-bed gas well. And then, high-pressure grouting is carried out at an extension grouting section of the coal bed gas well, and water-conducting cracks 18 (weathering cracks, tectonic cracks, karst cracks or karst caves) of a water-resisting layer of the coal bed bottom plate 4 are filled, so that the strength of the weak water-resisting layer is strengthened, the water-conducting cracks are sealed, a water source supply channel is cut off, the possibility of water inrush of the coal bed bottom plate is reduced, and the comprehensive reutilization of the waste coal bed gas well is realized.
The construction process of the invention is as follows:
1) selecting a coal bed gas well, a drilling machine and construction materials for preparation;
2) a pneumatic down-the-hole hammer is put along the coal bed gas well to drill a drill hole 16 of the extension grouting section of the coal bed gas well, the drill hole penetrates through a water-resisting layer 4 of a coal bed bottom plate and a water guide crack 18 of the water-resisting layer to reach a hole bottom 19, the final hole depth Hz of the drill hole is a disturbance area (40-60 m can be taken) below the coal bed bottom plate or is close to a water-bearing layer top plate, and the drill is lifted;
3) performing a water pressure test in the well, and measuring the permeability of the borehole 16 of the extension grouting section;
4) and (3) a high-pressure grouting device is put into the hole bottom 19, a grout stop plug 17 is arranged at the top of the drilling hole of the grouting section, and high-pressure grouting is carried out in the hole, wherein the grouting parameters are as follows:
① grouting slurry proportion is pure cement slurry, the concentration can be adjusted according to parameters such as drilling hole slurry suction amount, hole pressure and the like by taking the water-cement ratio of 1: 1.6 and the density of 1.65t/m3 as the reference, and the optimal proportion is determined by a grouting test;
② grouting final pressure Pz, wherein the grouting final pressure can adopt 6-10MPa based on the orifice pressure, and is determined by a grouting test;
③ maximum grouting amount Qz the maximum grouting amount is estimated from the grouting range and the fracture rate.
5) After grouting, waiting for solidification;
6) if the sectional grouting is carried out, grouting from the bottom of the hole is needed, grouting at the upper part is carried out after grouting at the lower part is finished, and the steps 4) -5) are repeated until the borehole 16 of the extension grouting repair section is completely grouted and reinforced and is in waiting for setting;
7) adopting a pneumatic down-the-hole hammer to sweep the drill hole 16 of the extension grouting repair section and drill the hole to the bottom 19 of the hole;
8) and performing a pressurized water test in the well again, and measuring the permeability of the borehole 16 of the extension grouting section. If the permeability is not satisfactory, repeating 4) -6); if the permeability meets the requirement, stopping repairing and grouting, and filling the coal bed gas well with cement soil slurry to a position above the coal bed top plate to form plugging slurry 21;
9) and (4) sealing and protecting the wellhead of the coal-bed gas well.

Claims (1)

1. A method for repairing a weak zone of a water-resisting layer of a coal bed bottom plate by using a coal bed gas well is characterized in that the water-resisting layer of the coal bed bottom plate is reinforced by using a waste coal bed gas well, and a hole of an extension grouting repairing section of a downward extension section of the coal bed gas well is formed by drilling at the bottom of the waste coal bed gas well; then high-pressure grouting is carried out through the extending grouting repairing section drill hole, and a water guiding crack in a water-resisting layer of the coal seam floor is filled, so that the strength of the weak water-resisting layer of the coal seam floor is reinforced, the water guiding crack is sealed, a water source supply channel is cut off, and the possibility of water inrush of the coal seam floor is reduced;
the specific construction process comprises the following steps:
1) selecting a coal bed gas well, a drilling machine and construction materials for preparation;
2) a pneumatic down-the-hole hammer is put along the coal bed gas well to drill a drill hole in the extension grouting section of the coal bed gas well, when the drill hole in the extension grouting repair section is constructed, the drill hole is continuously drilled from the bottom of a two-cut drill hole or a three-cut drill hole of the original abandoned coal bed gas well, and a water flowing crack of the coal bed bottom plate passes through a water-resisting layer of the coal bed bottom plate to the bottom of the hole to form a drill hole in the extension grouting repair section;
3) performing a water pressure test in the well, and measuring the permeability of the drill hole of the extension grouting section;
4) a high-pressure grouting device is put into the bottom of the hole, a grout stop plug is arranged at the top of the drilled hole of the extension grouting repairing section, and high-pressure grouting is carried out in the hole;
5) after grouting, waiting for solidification;
6) adopting a pneumatic down-the-hole hammer to carry out hole sweeping on the drill hole of the extension grouting repairing section and drill the drill hole to the bottom of the hole;
7) performing a pressurized water test in the well again, measuring the permeability of the drill hole of the extension grouting section, and repeating the steps 4) -5) if the permeability does not meet the requirement; if the permeability meets the requirement, stopping repairing and grouting, and filling the coal bed gas well with cement soil slurry to a position above the coal bed top plate to form plugging slurry;
8) sealing and protecting the wellhead of the coal-bed gas well;
if the segmented grouting is adopted, grouting from the bottom of the hole is started, grouting at the lower part is finished, then grouting at the upper part is carried out, and the steps 4) -5) are repeated until all the holes in the extended grouting repair segment are grouted and reinforced, and waiting for setting;
the final hole depth of the drill hole of the extension grouting repairing section is 40-60 m below the coal seam floor or the drill hole reaches the top plate of the aquifer;
the grouting slurry adopts pure cement slurry with the water-cement ratio of1: 1.6, density 1.65t/m3
The final pressure of the grouting is 6-10 MPa.
CN201710535523.XA 2017-07-04 2017-07-04 Method for repairing weak zone of coal seam floor water-resisting layer by utilizing coal seam gas well Active CN107313743B (en)

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Publication number Priority date Publication date Assignee Title
CN110630211B (en) * 2018-08-31 2021-08-17 中国矿业大学 Method for blocking overburden mining-induced fracture by ultrasonic in-situ slurry making
CN112664159A (en) * 2020-12-24 2021-04-16 北京大地高科地质勘查有限公司 Horizontal directional leaking stoppage method for small-sized cracks of coal seam roof

Citations (4)

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Publication number Priority date Publication date Assignee Title
CN201474608U (en) * 2009-08-19 2010-05-19 兴和鹏能源技术(北京)有限公司 Coal-bed-gas production-increase and gas water-inrush-prevention horizontal well
CN103216249A (en) * 2013-04-02 2013-07-24 中国矿业大学 Waterproof support method of water sump of water-swellable soft rock of underground coal mine
CN106437790A (en) * 2016-12-02 2017-02-22 淮北矿业股份有限公司 High-pressure-intensity water-containing layer karst fissure grouting method of difficult mining coal seam base plate thin-layer limestone
CN106545296A (en) * 2016-12-02 2017-03-29 淮北矿业股份有限公司 A kind of surface drilling grouting treatment method of deep mining coal seam base plate limestone water damage

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201474608U (en) * 2009-08-19 2010-05-19 兴和鹏能源技术(北京)有限公司 Coal-bed-gas production-increase and gas water-inrush-prevention horizontal well
CN103216249A (en) * 2013-04-02 2013-07-24 中国矿业大学 Waterproof support method of water sump of water-swellable soft rock of underground coal mine
CN106437790A (en) * 2016-12-02 2017-02-22 淮北矿业股份有限公司 High-pressure-intensity water-containing layer karst fissure grouting method of difficult mining coal seam base plate thin-layer limestone
CN106545296A (en) * 2016-12-02 2017-03-29 淮北矿业股份有限公司 A kind of surface drilling grouting treatment method of deep mining coal seam base plate limestone water damage

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