Composite fracturing and uniform permeability-improving method for tree-like boreholes in coal seams of underground coal mine

A composite fracturing and coal seam technology, applied in drilling equipment and methods, earthwork drilling, drilling equipment, etc., can solve the problems of high cost, poor effect, low efficiency, etc., and achieve large drilling size and good rock breaking effect. , the effect of small size

Active Publication Date: 2015-12-16
CHONGQING UNIV
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Problems solved by technology

[0006] The purpose of the present invention is to overcome the shortcomings of low efficiency, poor effect and high cost in the application of intensive drilling hydraulic fracturing pre-dr

Method used

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  • Composite fracturing and uniform permeability-improving method for tree-like boreholes in coal seams of underground coal mine
  • Composite fracturing and uniform permeability-improving method for tree-like boreholes in coal seams of underground coal mine
  • Composite fracturing and uniform permeability-improving method for tree-like boreholes in coal seams of underground coal mine

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Embodiment 1

[0061] Embodiment 1: see figure 1 , figure 2 and image 3 In the following, taking drilling into a multi-layer sub-hole network as an example, the detailed process of the method for uniform anti-permeability enhancement of tree-shaped coal seam drilling and fracturing in underground coal mines of the present invention will be described in detail. The thickness of the coal seam is 5m, two layers of sub-hole networks are designed, the distance between the sub-hole networks is 2m, and the upper layer of sub-hole networks is 1.5m away from the roof; because the coal is hard and the buried depth is medium, the design drilling pressure is 32Mpa, and the angle between the sub-holes 45°, the sub-hole length is 18m, and the fracturing pressure is 30Mpa. The specific operation steps are as follows:

[0062] (1) Drill the pilot hole in advance to the coal seam (17) in the rock roadway (19) to form the mother hole (20) of tree-shaped drilling. Drilling needs to be drilled to the roof...

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Abstract

The invention discloses a composite fracturing and uniform permeability-improving method for tree-like boreholes in coal seams of an underground coal mine. The composite fracturing and uniform permeability-improving method is suitable for permeability improvement of soft low-permeability coal seams, and is characterized in that a gas exhausting and mining hole serve as a mother hole, uniformly distributed self-advancing boreholes serve as tree-like son boreholes, and a tree-like borehole net is subjected to hole-sealing fracturing. Compared with a conventional hydraulic fracturing method, the composite fracturing and uniform permeability-improving method can realize uniform fracturing of the low-permeability coal seams to enlarge the fracturing range of single crossing boreholes, so that uniform permeability improvement is achieved, and the shortcomings that the crossing boreholes subjected to conventional hydraulic fracturing are low in utilization ratio, and a single major fracture can damage top and bottom beds are overcome. The composite fracturing and uniform permeability-improving method is simple to operate, large in permeability improvement range and good in permeability improvement effect and provides a guarantee for safety production of the underground coal mine.

Description

technical field [0001] The invention relates to a uniform anti-permeability method for tree-like drilling and composite fracturing of underground coal seams in coal mines, which belongs to the technical field of gas control in underground coal mine areas, and is especially suitable for comprehensive anti-permeability of soft and low-permeability coal seams. Background technique [0002] Most of the coal seams in my country are high-gas and low-permeability coal seams, and the gas gushes out with the coal seam mining, which leads to frequent coal mine gas accidents and wastes energy. At present, gas drainage is the fundamental method to solve the gas problem. There are various methods of gas extraction in coal mines in my country. The intensive drilling pre-extraction method is mainly used in underground mines. The intensive drilling pre-extraction method requires drilling a large number of bed-crossing boreholes from the rock roadway to the coal seam, especially when the roc...

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Application Information

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IPC IPC(8): E21B43/26E21B7/00E21B33/13
Inventor 卢义玉葛兆龙夏彬伟汤积仁周哲左少杰程玉刚宋晨鹏
Owner CHONGQING UNIV
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