Drilled hole effective extraction radius measuring method based on gas content method

Abstract

The invention provides a drilled hole effective extraction radius measuring method based on a gas content method, and belongs to the technical field of coal seam gas extraction. The method comprises the following steps that (1) the gas extraction rates under the different residual gas content conditions are respectively calculated; (2) the gas extraction rate eta 5 is determined according to the regulations of the Coal Mine Gas Extraction Basic Index; (3) the gas extraction rate eta is calculated; (4) the total extraction quantity of gas is calculated; (5) the number N of extraction drilled holes is calculated; (6) the N drilled holes are evenly distributed in an extraction drilled hole control area, and the drilled hole extraction radius within certain extraction time is calculated. The effective extraction radius can guide to design the reasonable extraction drilled holes, the aim of eliminating prominent dangerousness can be achieved through the method on the premise of meeting the pre-extraction time, and a large amount of manpower and a large number of financial resources and material resources can be saved.

Description

technical field [0001] The invention relates to the technical field of coal seam gas drainage, in particular to a method for measuring the effective drainage radius of a borehole based on a gas content method. Background technique [0002] Determining the reasonable extraction radius of coal seam gas is one of the most important technical tasks to achieve mine drainage standards. Reasonable drainage radius or drainage drilling spacing is obtained by making full use of the allowable pre-drainage time under certain conditions, reducing the amount of drilling work, and improving the optimization parameters of drainage efficiency. The traditional method of determining the drainage radius may obtain investigation results when the air permeability is good and the pressure measurement conditions of the coal seam are good, but its test efficiency is low; when the air permeability of the coal seam is poor, the measurement success rate is extremely low and the practicability is poor. ...

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Problems solved by technology

[0004] In view of this, the purpose of the present invention is to overcome the above-mentioned deficiencies and provide a method for measuring the effective drainage radius of a borehole based on the gas content method. This method solves the problem of low success rate of traditional measurement methods and is used to guide mine gas disaster control

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