Hydraulic fracturing control method of cut tight roof/top coal

A hydraulic fracturing and hard roof technology, which is applied in earth square drilling, surface mining, underground mining, etc., can solve problems such as potential safety hazards, large-area pressure on the roof, and gas exceeding the limit, so as to prevent sudden extrusion and reduce Air leakage, improve the effect of leakage

Active Publication Date: 2014-01-22
CHINA UNIV OF MINING & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] In many mining areas in my country (such as Yulin Shendong mining area, Datong mining area, etc.), there are hard roofs with high strength, large thickness, strong integrity, and no joints and fissures that occur directly on the coal seam or on the thinner direct roof. Since the roof of the coal mining face is supported by anchor cables + anchor rods + reinforced steel strips, the support strength is high, resulting in the overhang area of ​​the roof of the coal mining face during the initial mining period reaching several thousand square meters When the roof collapses in a large area, it is easy to squeeze out the gas accumulated in the goaf suddenly, causing the gas to exceed the limit and affecting the safe production of the working face; the roof collapse in the goaf is not timely , it is easy to cause air leakage from the side of the work facing the goaf, forming a safety hazard
[0003] In many coal mines, the hard or "two hard" (hard coal seam, hard roof) extra-thick coal seams are mined by fully mechanized caving. The phenomenon of gas exceeding the limit during the initial pressurization has affected the safe and normal recovery of the working

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  • Hydraulic fracturing control method of cut tight roof/top coal
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  • Hydraulic fracturing control method of cut tight roof/top coal

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Embodiment 1

[0026] Embodiment one: if figure 1 , figure 2 As shown, the average thickness of the coal seam in a certain mine is 2.28m, the height of the cut hole is 2.8m, the length is 300m, the width is 7.8m, and the length of the anchor cable is 8m; the immediate roof is dark gray sandy mudstone with an average thickness of 13.27m; the old roof is gray siltstone, The average thickness is 21.8m, and the immediate bottom is dark gray sandy mudstone, with an average thickness of 1.42m; the cut hole support is anchor cable + anchor rod + steel belt support. First use the drilling rig to construct two rows of fracturing boreholes 2 on the inner roof / top coal 1 of the cut hole 10, and the fracturing boreholes 2 near the front side of the cut hole 5 are arranged obliquely to the advancing direction of the coal mining face. The fracturing drill holes 2 near the auxiliary side of the hole are arranged vertically to the roof / top coal 1; a row of fracturing drill holes 2 is arranged near the fro...

Embodiment 2

[0027] Embodiment two: if Figure 5 As shown, the thickness of the coal seam in a mine is 7.25-20.19m, with an average of 11.17m, the thickness of pure coal is 4.3-19.34m, with an average of 10.02m, containing 2-10 layers of gangue, and the thickness of gangue is 0.2-6.8m, with an average of 1.15m. Single layer thickness 0.05 ~ 1m. The lithology of gangue is: gray-brown kaolinite, gray-black carbonaceous mudstone, mudstone, and local dark gray siltstone. Laoding is gray-white, dark gray, variegated siltstone, fine sandstone, medium-grained sandstone, coarse sandstone, and pebble-bearing coarse sandstone alternately occurring. The main composition is quartz, followed by feldspar and dark minerals. The cementation is dense and hard. The working face is arranged in three lanes, adopting the ventilation mode of "inlet, one back and one exhaust". The roof high suction lane 14 is excavated and arranged along the roof. 20m. The height of the cut hole 10 is 3.5m, the thickness of c...

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Abstract

The invention relates to a hydraulic fracturing control method of cut tight roof/top coal. The method comprises the following steps: constructing two rows of fracturing drill holes at intervals in the roof/top coal above an open-off cut by a drilling machine to a set depth, wherein one row of fracturing drill holes is close to a main upper of the open-off cut while the other row is close to an auxiliary upper of the open-off cut; constructing a row of anchor cable drill holes to the roof/top coal at the left and right ends of the open-off cut, respectively; or constructing rows of fracturing drill holes in different directions in a measure lane of the roof above the open-off cut; carrying out hydraulic fracturing on the drill holes, so that one or more cracks are generated on a rock body in a given plane to split the rock stratum to blocks or layers in certain shapes and sizes so as to damage the integrity of the rock and reduce the strength of the rock. Therefore, pressure of the roof in a large area and sudden extrusion of accumulated gases in a worked out section in an early mining stage on a coal face are prevented, air leak on the coal face is reduced, and the safety is ensured. Meanwhile, caving of top coal can be improved. The method is simple, convenient to construct, safe and reliable and good in effect.

Description

technical field [0001] The invention relates to a roof hydraulic fracturing method, in particular to a method for controlling hydraulic fracturing of a hard roof / top coal with cut holes. Background technique [0002] In many mining areas in my country (such as Yulin Shendong mining area, Datong mining area, etc.), there are hard roofs with high strength, large thickness, strong integrity, and no joints and fissures that occur directly on the coal seam or on the thinner direct roof. Since the roof of the coal mining face is supported by anchor cables + anchor rods + reinforced steel strips, the support strength is high, resulting in the overhang area of ​​the roof of the coal mining face during the initial mining period reaching several thousand square meters When the roof collapses in a large area, it is easy to squeeze out the gas accumulated in the goaf suddenly, causing the gas to exceed the limit and affecting the safe production of the working face; the roof collapse in t...

Claims

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Application Information

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IPC IPC(8): E21C41/18
Inventor 黄炳香马剑岳崇光
Owner CHINA UNIV OF MINING & TECH
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