软厚煤层液态CO_2相变多点致裂增透技术
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摘要
针对松软、低透气性高瓦斯突出厚煤层瓦斯抽采效率低、抽采钻孔瓦斯浓度衰减快等问题,利用优化的液态CO_2相变致裂系统,在长平矿4306采区进行了(底板)穿层钻孔多点致裂试验。试验结果表明:CO_2相变多点致裂有效影响半径约为12. 5 m,且与致裂点数无关;瓦斯浓度随致裂点数的增加呈线性增加; CO_2相变致裂提高了瓦斯抽采浓度,随着时间的推移瓦斯浓度逐渐下降。因此,在煤层的不同位置和不同的时间对煤层进行致裂,是维持或提高煤层瓦斯抽采效率的可选方案。
In view of the problem in soft thick coal seam with low permeability and high gas content outburst,such as the gas extraction efficiency is low,the gas concentration of extraction borehole decreases quickly,by using the optimized liquid CO_2 phase transition fracturing system,the multi-point fracturing test of perforating borehole( floor) in 4306 mining area of Changping Coal Mine was carried out. The experimental results show that the effective influence radius of multi-discharge crack of CO_2 phase transition is about 12. 5 m,and it is independent of the number of cracking points; the gas concentration increases linearly with the number of cracking points; the concentration of gas extraction is increased by CO_2 phase transition cracking,and decreases with time going on. Therefore,it is an alternative to maintain or improve the gas extraction efficiency of coal seam to crack the coal seam at different locations and different times.
In view of the problem in soft thick coal seam with low permeability and high gas content outburst,such as the gas extraction efficiency is low,the gas concentration of extraction borehole decreases quickly,by using the optimized liquid CO_2 phase transition fracturing system,the multi-point fracturing test of perforating borehole( floor) in 4306 mining area of Changping Coal Mine was carried out. The experimental results show that the effective influence radius of multi-discharge crack of CO_2 phase transition is about 12. 5 m,and it is independent of the number of cracking points; the gas concentration increases linearly with the number of cracking points; the concentration of gas extraction is increased by CO_2 phase transition cracking,and decreases with time going on. Therefore,it is an alternative to maintain or improve the gas extraction efficiency of coal seam to crack the coal seam at different locations and different times.
引文
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[2]郭继圣,张宝优.我国煤层气(煤矿瓦斯)开发利用现状及展望[J].煤炭工程,2017,49(3):83-86.
[3]申宝宏,刘见忠,张泓.我国煤矿瓦斯治理的技术对策[J].煤炭学报,2007,32(7):673-679.
[4]李磊,李中军,武文宾.松软低透气性煤层井下水力压裂工艺技术研究[J].矿业安全与环保,2015,42(6):5-9.
[5]宋维源,王忠峰,唐巨鹏.水力割缝增透抽采煤层瓦斯原理及应用[J].中国安全科学学报,2011,21(4):78-82.
[6]王兆丰,范迎春,李世生.水力冲孔技术在松软低透突出煤层中的应用[J].煤炭科学技术,2012,40(2):52-55.
[7]侯松,翟文杰,董浩.低透气性煤层深孔预裂爆破增透技术应用[J].煤炭技术,2017,36(1):206-208.
[8]赵宝友,王海东.我国低透气性本煤层增透技术现状及气爆增透防突新技术[J].爆破,2014,31(3):34-37.
[9]韩颖,史晓辉,雷云,等.液态CO2相变致裂增透预抽瓦斯技术试验研究[J].煤矿安全,2017,48(10):17-20.
[10]罗朝义,江泽标,郑昌盛,等.低透煤层CO2相变致裂增透解吸技术的应用[J].西安科技大学学报,2018,38(1):59-64.
[11]王兆丰,李豪君,陈喜恩,等.液态CO2相变致裂煤层增透技术布孔方式研究[J].中国安全生产科学技术,2015,11(9):11-16.
[12]雷云,刘建军,张哨楠.CO2相变致裂本煤层增透技术研究[J].工程地质学报,2017,25(1):215-221.
[13]邹永洺.煤与瓦斯突出煤层CO2相变致裂增透技术试验研究[J].煤矿安全,2018,49(3):5-8.
[14]李豪君,王兆丰,陈喜恩,等.液态CO2相变致裂技术在布孔参数优化中的应用[J].煤田地质与勘探,2017,45(4):31-37.
[15] LU Tingkan,WANG Zhaofeng,YANG Hongming,et al.Improvement of coal seam gas drainage by under-panel cross-strata stimulation using highly pressurized gas[J].International Journal of Rock Mechanics&Mining Sciences,2015,77:300-312.