Experimental Study On The Technology Of Increasing Permeability By Drilling The Coal Bed With High-Prssure Gas

The poor effects of gas extraction, because most of the coal seams in China are high gas and low-permeability. Therefore, it cannot solve the problems of gas in mine with the methods of"draining gas before coal mining"and"draining while mining".Directing at how to increase the permeability in high gas and low permeability coal seam,this paper advance a new technology of increasing permeability that drilling the coal bed with high-pressure gas .It has high adaptability and high safety compared with other technologyies that of"hydraulic facturing"and"hydraulic cutting seam"and"presplitting blasting".Its main contents bases on the theory of seam gas occurrence and fluid and the mechanism of high-pressure air burst ,analyses and discusses its process and characteristics during the high-pressure air burst in coal seam in detail . Selecting samples from 30 groups in Haizhou coal mine and Aiyou coal mine of Fuxin mining Group, 10groups for compression experiment and 20groups for high-pressure air burst experiment in the laboratory, recording physical parameters and experimental parameters of coal samples, calculating the permeability before and after the high-pressure air bust of the coal samples.The study shows that:(1) Permeability of coal samples as a whole increased after gas burst, the average increase of 81% or more.(2) The greater the pressure of high pressure gas, the bigger the permeability increment of the coal samples after gas burst .according to the permeability increment and the pressure of the 10coal samples from Haizhou mine ,regression analysis shows that the permeability incrementΔk was a power function with the pressure p,the function isΔk =2×10^-13p^11.148(3) The more hard coal, the greater the permeability increment after gas burst.It raises the production and reduces the menace of coal-and-gas outburst, further solves the problem of gas concentration and gas outburst on working face in the high gas-outburst coal seam, so it is a technology with great valuable to popularize...