摘要
针对轿子山煤矿M9煤层渗透率低、瓦斯含量高、压力大等特点,将液态CO_(2)相变致裂技术应用于本煤层增透工程试验。从多角度探究了CO_(2)相变致裂增透原理,通过分组对比试验,重点考察致裂孔不同施工顺序、不同装液量对有效抽采半径的影响。结果表明:预抽时间相同时,先施工辅助钻孔致裂时会提供更多的裂隙通道,应力波传播时阻力降低更多,从而使瓦斯抽采有效半径更大;预抽时间90d内致裂孔瓦斯抽采有效半径与装液量呈正相关,预抽时间在90~150d时,在构造应力作用下,钻孔变形大,装液量越多的致裂孔瓦斯抽采有效半径越小;致裂后钻孔瓦斯抽采有效半径是普通孔的3.6~4.2倍,单孔抽采瓦斯纯流量平均增加2.9~5.8倍,瓦斯抽采浓度增加2.3~3.1倍,瓦斯有效预抽时间缩短65%以上。研究结果可为瓦斯抽采钻孔的合理布置提供参考依据。
In view of the high gas content, high pressure, and low extraction efficiency in the M9 coal seam of Jiaozishan Coal Mine, the liquid CO_(2) phase change fracturing technology was applied to the coal seam permeability-enhancing project test. The principle of CO_(2) phase change fracturing and permeability enhancement was explored from multiple angles. Through grouped comparative tests, the focus was on the effects of different construction sequences of fracturing holes and different liquid loadings on the effective extraction radius. The gas content index method was used to study the law of the change of gas extraction radius at different pre-extraction time is described. The results show that: under the same pre-extraction time, more fracture channels will be provided when the auxiliary drilling is constructed first, and the resistance reduces when the stress wave propagates, so that the effective extraction radius of gas is larger;within 90 days of pre-extraction, the effective radius of gas extraction from fracture holes is positively correlated with the amount of liquid;when the pre-extraction time is 90 to 150 days, under the action of tectonic stress, the borehole deformation is large, and the effective radius of gas extraction in the fracture hole with more liquid is smaller;after fracturing, the effective radius of gas extraction in boreholes is larger, 3.6~4.2 times of that of ordinary holes. The net gas flow rate of single-hole extraction increases by 2.9~5.8 times on average, and the gas extraction concentration increases by 2.3~3.1 times. The pre-extraction time is shortened by more than 65%.
作者
衡献伟
付金磊
李青松
马曙
HENG Xian-wei;FU Jin-lei;LI Qing-song;MA Shu(Guizhou Coal Mine Design Research Institute Co.,Ltd.,Guiyang 550025,China;Guizhou Mine Safety Scientific Research Institute Co.,Ltd.,Guiyang 550025,China;School of Safety Engineering,China University of Mining and Technology,Xuzhou 221116,China)
出处
《煤炭工程》
北大核心
2021年第10期126-130,共5页
Coal Engineering
基金
贵州省科学技术基金资助项目(黔科合基础[2019]1189号,黔科合基础[2019]1426号)
黔科合平台人才[2019]5675
黔科合支撑[2020]2Y056号
黔科合支撑[2020]4Y049号
黔科合支撑[2021]一般348。
关键词
CO_(2)相变致裂
瓦斯抽采
增透
抽采半径
CO_(2)phase change fracturing
gas extraction
permeability-enhancing
extraction radius
