低透煤层CO2气相致裂卸压增透技术研究

Study on Gas Phase Cracking and Pressure Reducing Technology of CO2 in Low Permeability Coal Seam

针对高瓦斯低透气性煤层效率低,提出CO2相变致裂爆破增透技术来提高抽采效率。通过理论分析和FLAC3D数值模型研究分析液态CO2相变致裂爆破煤层增透效果,并进行了现场试验,结果证明:当爆破参数为CO2爆破器间距5 m、爆破孔间距7.5 m,此时多孔连续爆破煤层增透效果最好;爆破后煤体透气性距爆破孔由远及近的变化规律为非线性增加。1312材料巷实施液态CO2相变致裂爆破增透技术后,透气性系数增大了16.89~20.97倍,平均瓦斯抽采混量和浓度分别提高43.1%和55.8%,保证了矿井安全生产和煤层气资源的有效利用。

In view of the low efficiency of high gas permeability and low permeability coal seam,a CO2 phase change cracking blasting anti-reflection technology is proposed to improve the extraction efficiency.Through theoretical analysis and FLAC3D numerical model research,the effect of liquid CO2 phase change cracking blasting coal seam anti-reflection is analyzed and field test is carried out.The results show that when the blasting parameters are CO2 blaster spacing 5 m and blasting hole spacing7.5 m,this time porous the effect of continuous blasting coal seam is the best.After blasting,the variation of the permeability of the coal body from the far and near blasthole is nonlinear.After 1312 material roadway implemented liquid CO2 phase change cracking blasting anti-reflection technology,the gas permeability coefficient increased by 16.89 to 20.97 times,and the average gas extraction mixing concentration and concentration increased by 43.1%and 55.8%,respectively,ensuring mine safety production and coal seam effective use of gas resources.