Method for both protecting soft coal seam borehole and improving gas drainage efficiency

Abstract

The invention discloses a method for both protecting soft coal seam borehole and improving gas drainage efficiency. A method that large plastic balls with holes and small plastic balls with holes aresequentially filled is adopted, the two types of plastic balls with holes can play a protective supporting role for a gas drainage borehole after the borehole is filled, and the possibility of collapse and deformation of the borehole is reduced; a formed gas drainage channel is kept smooth; and with the decrease of the gas drainage concentration, water is injected into the borehole, and the waterneutralizes with quicklime to accelerate the gas desorption after a coal body is heated, so that the efficiency of the gas drainage is improved. By injecting of the water many times, the reaction of calcium oxide and the water can be effectively utilized to release heat, and the efficiency of the gas drainage can be gradually improved. The method integrates borehole protection and improvement of the gas desorption rate, the gas drainage efficiency is high, the effect is good, and the smooth gas drainage channel can be ensured without special installation equipment, so that the whole implementation process is convenient and easy, the method is convenient for field use, and the practicability is wide.

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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