Soft coal seam roof directional drilling hydraulic fracturing anti-reflection device and application method

Abstract

The invention discloses a soft coal seam roof directional drilling hydraulic fracturing anti-reflection device and an application method, and belongs to coal mine disaster prevention and control methods. A directional long drill hole is constructed in a roof rock stratum in a coal roadway of a soft coal seam, a fracture network is formed in the roof rock stratum through a hydraulic sand fracturing technology, and fluid pressure is continuously improved to enable fractures to extend into the soft coal seam, the fracture network in the coal seam can be kept unclosed for a long time due to the influence of the non-homogeneous interface effect on the contact face of the soft coal seam and the roof rock stratum, meanwhile, the directional long-drill-hole staged fracturing technology can be achieved through mutual cooperation of a packer and a cut-off device, and the fracturing effect is improved. The method can achieve the purposes of releasing crustal stress, increasing coal seam gas permeability and strengthening soft low-permeability coal seam gas extraction, the working efficiency is high, and the engineering cost is saved.

Description

technical field [0001] The invention relates to the field of coal seam gas drainage technology research, in particular to a soft coal seam roof directional drilling hydraulic fracturing anti-permeability device and an application method. Background technique [0002] As the world's largest producer and consumer of coal resources, coal accounts for more than 60% of energy consumption in my country's energy structure. With the development of coal mining in my country, the stress and gas pressure of coal seams continue to increase, and coal and gas outburst disasters are becoming more and more serious. Especially, the prevention and control of coal-rock gas dynamic disasters in areas where tectonic coal occurs is urgent. At present, gas drainage is the core means to eliminate gas disasters in coal seams and realize safe mining. However, due to the soft and broken characteristics of structural coal, especially when there are thick and hard rock layers on the roof, the ground str...

AI Technical Summary

Problems solved by technology

However, there are still some problems in the actual implementation process

The main performance is that the coal body is soft, broken, and the structure is complex. After the implementation of hydraulic permeability enhancement measures to generate a fracture network, the drainage boreholes are prone to "closing effects" under the action of in-situ stress, resulting in rapid flow attenuation during gas drainage and poor drainage effects. Not obvious; and due to the limitations of the physical and mechanical properties of soft coal, coal seam drilling is difficult, and fluids entering are more likely to cause problems such as hole collapse and blockage

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