Bed-parallel drilling slot pressure relief permeability increase method

Abstract

The invention discloses a bed-parallel drilling slot pressure relief permeability increase method which includes the steps: (1) performing construction on bed-parallel gas extraction drilling by the aid of a high-pressure hydraulic slotting device to form a drilled hole according to bed-parallel gas extraction drilling design requirements; (2) leading high-pressure water into the high-pressure hydraulic slotting device without withdrawing a drill to rotatably and circumferentially cut coal to form a disc-shaped slot; (3) withdrawing the drill after the disc-shaped slot is formed, and radiallycutting the coal without rotating a drill bit and a drill rod to form a radial slot; (4) repeating the step (2) and the step (3), and forming a plurality of disc-shaped slots and a plurality of radialslots in the same drilled hole; (5) repeating the step (1) to the step (4), and performing drilling and slotting on the other bed-parallel drilled holes. According to the method, horizontal and vertical stress of a coal layer is reduced, drilling gas extraction concentration and flow is improved, the bed-parallel drilling number of a working surface is decreased, and the method is simple and convenient to operate.

Description

technical field [0001] The invention relates to the technical field of gas drainage in coal mines, in particular to a method for pressure relief and permeability enhancement by slit drilling in bedding. Background technique [0002] Coal and gas outbursts and rock bursts in deep mining are very serious and common natural disasters that threaten the safe production of coal mines. According to incomplete statistics, gas dynamic disasters have occurred in more than 20 countries and regions. The total number of disasters is more than 50,000, and more than 35,000 people died. Among them, rock burst accidents are also increasing year by year. With the increase of mining depth, the gas pressure, gas content and ground stress of coal seams increase, and the outburst danger of outburst mines becomes more and more serious, which has become one of the main problems threatening the safe production of mining areas; in addition, the increase of mining depth, The increase of mine pressure...

AI Technical Summary

Problems solved by technology

Although these measures have achieved certain effects in improving the drainage rate of low-permeability and high-gas coal seams, there are obvious limitations. Some mines have adopted anti-permeability measures to induce accidents such as outbursts and tunnel collapses, and the effect is not good; in addition, continuous unloading of coal seams is not possible. It cannot fundamentally guarantee the safe and efficient production of the mining face

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