A method for drilling protection in soft coal seams and improving gas extraction efficiency

Abstract

The invention discloses a method for protecting drilling holes in soft coal seams and improving the efficiency of gas drainage. The method of filling large-scale plastic balls with holes and small plastic balls with holes in sequence is used. It can protect and support the gas drainage borehole, reduce the possibility of its collapse and deformation; keep the formed gas drainage channel smooth; as the concentration of gas drainage decreases, inject water into the borehole, water and quicklime A neutralization reaction occurs, and the gas desorption is accelerated after the coal body is heated, thereby improving the efficiency of gas extraction. By injecting water multiple times, the heat released by the reaction of calcium oxide and water can be effectively utilized, and the efficiency of gas extraction can be gradually improved. The invention integrates drilling protection and gas desorption rate improvement, high gas drainage efficiency and good effect, and it can ensure smooth gas drainage channel without special installation equipment, so the whole implementation process is convenient and simple to operate, convenient Field use, with a wide range of practicability.

Description

technical field [0001] The invention relates to a method for improving gas drainage efficiency in soft coal seams, in particular to a method for both drilling protection in soft coal seams and improving gas drainage efficiency. 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 g...

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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, complicated on-site operation, and not widely applicable; In addition, the above two methods are only for the protection of gas drilling, and do not provide a solution to improve the efficiency of gas drainage, which makes the effect of gas drainage for a long time poor

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