Drilling with casing method for gas extraction hole of soft broken coal seam

Abstract

The invention relates to a drilling with casing method for a gas extraction hole of a soft broken coal seam. The problems that a deep gas extraction hole in a soft broken coal seam is difficult to drill and the hole forming effect is poor can be effectively solved. According to the technical scheme for solving the problems, the method comprises the following steps: 1, stabilizing a drilling machine; 2, installing a drilling tool; 3, drilling; 4, carrying out drilling with casing operation; 5, connecting a long sleeve and a drill stem; 6, rinsing boring mud; 7, drilling the deep hole in circulation; and 8, retreating the drilling tool. The construction method disclosed by the invention is scientific and reasonable, the collapse of a hole wall is avoided, and meanwhile, a smooth slag discharge channel is provided for the boring mud at the bottom of the hole, so that not only are the drilling speed and the drilling depth of the gas hole improved, but also the target of protecting the hole is achieved, and the gas extraction efficiency is significantly improved. The method is simple and practical in operation, the operation environment is improved, and the drilling with casing method is an innovation of gas extraction methods of a soft broken coal seam.

Description

technical field [0001] The invention relates to the technical field of gas drainage in coal mines, in particular to a drilling method for gas drainage holes and pipes in soft and broken coal seams. Background technique [0002] For a long time, gas drainage in high-gas mines is the premise of safe and efficient production in coal mines, and is the key factor to realize the maximum economic benefits of mines. At present, gas drainage holes are generally drilled by using extensions of drill bits and drill pipes. After the holes are formed, drainage is carried out without any treatment on the boreholes. This hole-forming process is more suitable for medium-hard coal seams, but in soft and broken coal seams, it often shows: ①During the drilling process, the drilling stability is poor, the hole wall often collapses before drilling, and the hole-forming quality is poor; ②Due to The wall of the borehole collapses in a large area, the discharge channel of the drilling slag is block...

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Problems solved by technology

[0003] In view of the above situation, in order to solve the defects of the prior art, the purpose of the present invention is to provide a method for drilling gas extraction holes in soft and broken coal seams with pipes, which can effectively solve the difficulties of deep hole drilling of gas drainage holes in soft and broken coal seams and The problem of poor hole forming effect

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