低透煤层CO_2相变致裂增透解吸技术的应用

Application of CO_2 phase transformation fracturing enhanced desorption technology in low permeability coal seam

针对贵州省喀斯特地质条件下松软低透高瓦斯煤层掘进过程中瓦斯抽采难度大、抽采效率低、抽采时间长等难点问题,提出应用CO_2相变致裂增透解吸技术提高煤层透气性系数、增大煤层透气性、提高瓦斯抽采量和抽采效率。研究了CO_2相变致裂增透解吸技术对绿塘煤矿工作面卸压增透效果,并与深孔预裂卸压增透技术效果进行了对比研究,发现该区域CO_2相变致裂增透技术增透效果较明显,CO_2致裂与深孔预裂相比较,前者煤层透气性系数约为后者透气性系数的1.9倍,CO_2致裂后的衰减系数比深孔预裂后衰减系数低约20%,CO_2致裂后平均抽采浓度约为70%,结果表明:采用CO_2相变致裂增透解吸技术后,该煤矿总体抽采效率提高了约6倍,抽采达标周期大幅缩短,为同类矿井的瓦斯治理提供了可借鉴技术与经验。

In order to improve the gas extraction effect of soft and low permeability coal seam in karst geological condition of Guizhou Province,the CO2 phase transformation fracturing enhanced desorption technology was applied to improve the permeability of coal seams,gas drainage quantity and drainage efficiency.The effect of CO2 transformation fracturing enhanced desorption technology and deep hole pre-cracking on the pressure relief was applied in Lv tang coal mine working face relieving stress,and improved permeability effect was compared with deep hole pre-cracking.It is pointed that the effect of CO2 transformation in this region is obvious,and the permeability coefficient of the former coal seam is about 1.9 times higher than that of the deep hole pre-cracking.CO2 attenuation coefficient after fracturing is about 20%lower than the deep hole pre splitting,CO2 average drainage concentration is about 70%.The results indicate that based on the CO2 phase transformation fracturing enhanced desorption technology,the overall coal mine drainage efficiency is increased by about 6 times,greatly shorten the period of extraction standards,provide a reference for the similar coal mine gas control.