利用CO_(2)气相压裂技术提高煤层透气性:以吉宁煤矿为例

Improving the permeability of coal seam with CO_(2)gas phase fracturing technique:a case study in Jining Coal Mine

为破解复杂低渗高瓦斯煤层瓦斯治理技术难题,本文以山西华晋吉宁煤矿2号煤层2203工作面为研究对象,通过采取CO_(2)气相压裂增透技术,对4组(共12个)抽采钻孔的瓦斯抽采浓度和瓦斯抽采纯量进行分析,得出有效致裂影响范围,进一步评价瓦斯抽采效果和防突效果。结果表明:该地质单元的有效致裂裂缝影响范围为6~7 m;常规抽采孔的瓦斯抽采纯量为0.018 m^(3)/min,与其相比,4组抽采钻孔百米瓦斯抽采纯量平均值为0.179 m^(3)/min,提升了8.9倍;在衰减区域,瓦斯抽采浓度均值64.7%、纯量均值0.150 m^(3)/min,在稳定区浓度,瓦斯抽采均值为73.2%、纯量均值0.188 m^(3)/min,相比稳定区域瓦斯抽采参数更高。该技术有效增大了2号煤层的透气性,提高了瓦斯抽采效率和煤巷掘进速度,减少了钻孔施工投入,缓解了采掘接替紧张的局面。

In order to solve the technical problems of gas treatment in complex low-permeability and high-gas coal seams,this paper takes the 2203 working face of No.2 coal seam in Jining Coal Mine,Huajin,Shanxi Province as the research object.By adopting the CO_(2)gas phase fracturing antipenetration technology,the gas extraction concentration and gas extraction purity of 4 groups(12)of extraction boreholes are analyzed,the effective extraction radius is inferred,and the effective fracturing range is determined.Then evaluate the effect of gas extraction and outburst prevention.The results show that:the influence range of effective cracking fractures in this geological unit is 6-7 m.The average gas extraction purity of the four groups of boreholes is 0.179 m^(3)/min,which is 9.9 times higher than that of the conventional extraction holes of 0.018 m^(3)/min.In the attenuation area,the average gas extraction concentration is 64.7%and the average gas extraction purity is 0.150 m^(3)/min.In the stable region,the average gas extraction concentration is 73.2%,and the average gas extraction purity is 0.188 m^(3)/min.It is found that the gas extraction parameter value in the stable region is higher.This technology can effectively increase the gas permeability of No.2 coal seam,improve the efficiency of gas extraction and the speed of coal roadway driving,reduce the investment of drilling construction,and relieve the tense situation of mining succession.