A method for controlling the expansion of coal mine fracturing cracks

A technology of fracture propagation and control method, applied in the field of fracture propagation control of fracturing in coal mines, can solve the problems of increasing the influence range of a single fracturing hole and not considering the direction of fracture propagation, so as to increase the effective fracturing range and reduce damage , the effect of reducing the pump pressure

Active Publication Date: 2018-05-29
CHONGQING JIAOTONG UNIVERSITY
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But it does not consider the direction of fracture propagation and how to greatly increase the range of influence of a single fracturing hole

Method used

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  • A method for controlling the expansion of coal mine fracturing cracks
  • A method for controlling the expansion of coal mine fracturing cracks
  • A method for controlling the expansion of coal mine fracturing cracks

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Embodiment Construction

[0032] An embodiment of the present invention is described below in conjunction with accompanying drawing:

[0033] see figure 1 , figure 2 and image 3 , the coal mine underground fracturing crack expansion control method proposed by the present invention, at first is to determine the position of the fracturing borehole 1 according to the calculation method and steps of the coal mine underground fracturing crack expansion control process parameters, and in combination with the physical and mechanical properties of the construction coal seam 17 , on both sides of the fracturing borehole 1, the pressure-holding water injection boreholes 2 are arranged at equal intervals according to the area of ​​the fracturing coal seam; then the hole sealing device is installed, the sealing material is allocated, and the fracturing borehole 1 and the pressure-holding water injection are performed using a grouting pump. Drill hole 2 is sealed by grouting, and the sealing effect should meet ...

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Abstract

The invention discloses a method for controlling the expansion of hydraulic fracturing cracks in underground coal mines. Arrangement of the expansion direction of the fracturing, (2) Grouting and sealing of the fracturing drilling and pressure-holding water injection drilling, (3) According to the calculated pressure-holding hole water injection pressure and single-hole pressure-holding water injection time, the pressure-holding water injection drilling (4) Hydraulic fracturing of the fracturing borehole. In the present invention, a number of boreholes are preset on both sides of the fracturing borehole according to the artificially expected expansion direction of hydraulic cracks, and pressure-maintaining water injection is performed on them before formal fracturing, so that a continuous band is formed around the fracturing borehole. In the high pore pressure area, hydraulic fractures can be induced to expand along the high pore pressure area, increasing the effective fracturing range; at the same time, reducing the crack initiation and expansion pressure of the fracturing drilling hole, reducing the damage to the coal seam roof and floor strata.

Description

technical field [0001] The invention relates to a method for controlling the expansion of underground fracturing cracks in coal mines. Background technique [0002] In recent years, hydraulic fracturing has been widely used in coal mine gas drainage enhancement. Underground coal mine hydraulic fracturing has a significant effect on increasing coal seam permeability, increasing gas pre-drainage concentration, and shortening gas drainage time. However, in the deep complex coal seam, the coal seam has the characteristics of high ground stress and the development of joints and fissures, which leads to a substantial increase in the initiation pressure of underground hydraulic fracturing, which greatly increases the deformation and damage of the roof and floor of the coal seam, the cost of corresponding fracturing equipment and safety risks. At the same time, the hydraulic fractures are easily disturbed during the expansion process, resulting in disordered crack expansion, and the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B43/26E21F7/00
Inventor 宋晨鹏卢义玉张旋夏彬伟贾云中葛兆龙汤积仁
Owner CHONGQING JIAOTONG UNIVERSITY
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