Method and device for repairing downhole coal-bed gas extraction drilled hole

Abstract

The invention relates to a method and device suitable for repairing a downhole failed gas extraction drilled hole. According to the method and the device, a guiding pipe outside the drilled hole is connected to a drainage pipeline through a flange and a quick connector, when the drainage flow or concentration of gas is greatly lowered, the flange is dismounted, a water pressure self-driven drilled hole repairing system device is connected, post-positioned reverse spray nozzles of a water pressure self-driven drill bit form reverse a jet flow so as to supply advancing power to the drill bit in the drilled hole, prepositioned forward outer-ring spray nozzles form an annular jet flow so as to supply rotating, reaming and deslagging power to the drill bit, and forward inner-ring spray nozzles form an annular jet flow and a center spray nozzle forms a forward jet flow, so as to supply power to slag removal and slag discharge; the exterior of the water pressure self-driven drill bit is of a shuttle-shaped structure, so that driving resistance can be reduced, and the withdrawing and reuse of the drill bit are facilitated. A simple and efficient method for repairing the failed drilled hole is provided, and the aims of prolonging the service time of the drilled hole and increasing the use efficiency of the drilled hole are achieved.

Description

technical field [0001] The invention relates to a coal mine safety control method, in particular to a fast and efficient repair method for underground gas drainage boreholes in coal mines. Background technique [0002] Gas drainage is an important means to prevent and control gas disasters and realize the comprehensive utilization of gas energy. With the continuous increase of mine mining depth, the gas drainage conditions tend to be more complicated. For example, when gas drainage is carried out in areas with high ground stress, surrounding rock fissures and soft coal seams, due to disturbances of ground stress and external forces, collapses often occur in boreholes. Holes, blocked holes and other phenomena lead to blockage of gas drainage channels, and the gas drainage flow rate and concentration are extremely low. For this problem, the commonly used method is to re-drill with a drilling rig according to the original drilling parameters. This method is not only time-cons...

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Problems solved by technology

However, this method is only suitable for coal cinders with small particle sizes, and it is difficult to insert a drainage pipe at the bottom of the hole, and it is impossible to discharge coal cinders and rock cinders with large particle sizes when the borehole collapses.

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