Method for ensuring smooth gas extraction channel of soft coal seam

Abstract

The invention discloses a method for ensuring a smooth gas extraction channel of a soft coal seam. The method is characterized in that a downward drilling hole is sequentially filled with small-numberperforated coal balls, medium-number perforated coal balls and large-number perforated coal balls, wherein the interiors of the perforated coal balls of various models are provided with spherical hollow structures and communicate with the outside through vent holes, and after the drilling hole is filled with the perforated coal balls of various models, a certain supporting effect can be achievedon the downward drilling hole, and the possibility of collapse and deformation of the downward drilling hole is reduced; in addition, due to the fact that the coal balls are spherical, gaps still exist after the coal balls make direct contact with each other in the drilling hole, at the moment, gas in the coal seam forms the gas extraction channel through the perforated coal ball gaps, vent holesand inner spherical hollow structures of various models, so that the gas extraction is smooth; and the coal balls rely on the inclination angle of the downward drilling hole during filling, and roll into the drilling hole under the action of the gravity of the coal balls so as to conduct protection support, and special installation equipment is not needed, so that field use is facilitated, and wide practicability is achieved.

Description

technical field [0001] The invention relates to a method for ensuring smooth gas extraction channels, in particular to a method for ensuring smooth gas extraction channels in soft coal seams. Background technique [0002] According to statistics, 52% of mines in China are high-gas mines, and gas control is a prerequisite for ensuring safe and efficient production in mines. However, the proportion of soft coal seams in my country is very high, and the main coal seams in many mining areas are soft, low-permeability, and high-gas coal seams, and many mines have the risk of coal and gas outburst. Pre-extraction of coal seam gas by construction drilling is an effective means of gas control, and it is also a measure commonly adopted by various coal mines. However, in the soft coal seam, more than 90% of the gas drainage holes will be deformed, collapsed or even closed for a short time after the gas drainage holes are formed, thus blocking the gas gushing and flowing channels, ser...

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Problems solved by technology

However, both of these two methods require the preparation of specific borehole pipes, and a variety of equipment must be used to cooperate with each other to achieve the effect of putting the borehole pipe into the gas borehole for protection, resulting in large capital investment and time-consuming for these two methods Laborious, complex on-site operation, not widely applicable

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