Quick pressure-relief gas discharge method for exposing super-thick and soft outburst coal seam in vertical wellbore

Abstract

The invention discloses a quick pressure-relief gas discharge method for exposing a super-thick and soft outburst coal seam in a vertical wellbore. The method comprises the following steps: designing discharge drilling holes in several circles along the contour of the wellbore heading face; dividing the drilling holes into a plurality of nine-hole thrusting units, and nine-hole injection units; drilling for each nine-hole thrusting unit and each nine-hole injection unit; conducting pressure test for drilling; thrusting coal of the 9 holes of the nine-hole thrusting units and the nine-hole thrusting units sequentially; constructing a gas inspection hole in the area of the nine-hole thrusting and nine-hole injection units in the thrusting, and measuring gas content; cementing the 9 drill holes of the nine-hole thrusting units and the nine-hole injection units after measuring the gas content; thrusting and cementing all the nine-hole thrusting units and the nine-hole injection units sequentially. The quick pressure-relief gas discharge method avoids the problem of cracking of the borehole wall after the change of the punching stress, and strengthens the coal, and increases the single hole discharge under the premise of ensuring the safety, and realizes the quick pressure-relief gas discharge of the super-thick and soft outburst coal seam.

Description

technical field [0001] The invention relates to a rapid pressure relief and gas discharge method for piercing through an ultra-thick, soft, and outburst coal seam by an underground shaft shaft, and is suitable for gas elimination and outburst discharge of the ultra-thick, soft, and outburst coal seam with a narrow working surface of the shaft shaft. Background technique [0002] The current "Regulations on the Prevention and Control of Coal and Gas Outbursts" stipulates in Article 49 (4) that the outburst prevention measures for the coal seam gas area in the coal seam area should be in the area where the coal seam is exposed. The minimum normal distance between the coal working face and the coal seam shall be implemented before 7m (the distance should be appropriately increased in the structural failure zone). The minimum control range of drilling is: 12m outside the roadway contour line at the coal mining site of Shimen, vertical shaft and inclined shaft (6m at the bottom o...

AI Technical Summary

Problems solved by technology

At the same time, for the soft coal seam, the air permeability is poor, and the downward drilling is easily affected by the water seal, which makes it difficult to discharge gas and the control range of a single hole is small

Based on the above factors, using the traditional gas discharge method, the number of drilling holes is huge, and the working face of the wellbore is small, so it is impossible to carry out construction

In order to increase discharge and reduce the number of boreholes, it is necessary to adopt hydraulic measures to relieve pressure and increase permeability. wall cracking

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