Water jet dense comb-shaped drilling type coal seam gas outburst reduction and pre-drainage treatment method for roadway to be excavated

Abstract

A water-jet intensive comb-shaped drilling method for coal seam gas outburst pre-drainage treatment method to be excavated, which includes the following steps: Step 1: construction to form a directional long borehole, step 2: construction to form a water-jet intensive comb-shaped borehole, Step 3: Sealing holes for gas extraction. The invention utilizes the extremely small-radius water jet dense comb-shaped branch drilling on the bottom plate of the roadway to be excavated in the coal mine, which reduces the drilling depth of a single branch hole, greatly increases the number of branch holes, and improves the coal seam growth rate of the directional long drilling. The effect of penetration and gas drainage has achieved the purpose of gas pre-drainage and outburst in the coal seam of the roadway to be excavated, and has ensured the safe excavation of the coal seam roadway.

Description

technical field [0001] The invention relates to the technical field of coal seam gas control, in particular to a water jet intensive comb-shaped drilling type coal seam gas outburst pre-extraction control method for roadway to be excavated. Background technique [0002] With the increase of coal mining depth in my country, the in-situ stress, gas gradient, gas content and gas emission volume continue to increase, high-gas mines and outburst mines are also increasing, and the frequency and intensity of coal and gas outbursts and gas overruns are also increasing. Therefore, it is necessary to take measures to prevent coal and gas outburst and gas overrun in underground coal roadway excavation. The pre-extraction of gas by drilling is an effective means to control gas outburst and overrun. At present, the main method of gas control in the coal roadway to be excavated is to first construct the gas drainage rock roadway in the coal roadway floor rock layer, and then construct the ...

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Problems solved by technology

The effect of gas pre-extraction by using the drilling roadway to drill through the layers is the best, but the construction period is long and the cost is high; the economy and period of gas pre-extraction by using the directional long drilling holes along the coal seam are good, but the main problems The problem is that the coal seams of high-gas or outburst mines are relatively broken, and the directional long boreholes in construction are prone to hole collapse or even drill stuck accidents under high ground stress and high gas pressure, which greatly affects the effect of drainage and outburst prevention; Although the pre-pumping of directional comb-shaped drilling in the floor can avoid accidents in the main hole to a certain extent, there are problems that the number of branch drilling is limited, and the drilling rate of the whole hole coal seam is low, and the drainage effect is difficult to guarantee.

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