高瓦斯低透气性煤层CO_2相变致裂增透技术研究  

Research on CO_2 phase-transition fracturing technology for permeability improvement in high gas and low permeability coal seam

作　　者：洪紫杰 王成[1,2] 熊祖强[1,2] 

机构地区：[1]河南理工大学能源科学与工程学院,河南焦作454003 [2]煤炭安全生产河南省协同创新中心,河南焦作454003

出　　处：《中国安全生产科学技术》2017年第1期39-45,共7页Journal of Safety Science and Technology

基　　金：国家自然科学基金项目(51304065;51274088;50908076)

摘　　要：针对高瓦斯低透气性煤层瓦斯抽采效果差,且炸药爆破增透存在危险性大等问题,采用理论分析与计算、数值模拟及现场实验等方法,分析了液态CO_2致裂增透煤层原理及煤层损伤,计算了液态CO_2致裂当量,模拟优化了关键部件释放管几何类型及参数,研究了相变致裂点数对致裂效果的影响。结果表明:CO_2相变致裂利用高压气体冲击破碎煤岩体,增强了煤岩层的裂隙发育及透气性;1 kg液态CO_2相变致裂爆炸的当量相当于398 g TNT炸药;关键部件释放管最优结构为空心圆柱结构,最优长度18 mm,最优直径24 mm,最优压力276 MPa;瓦斯抽放影响半径与致裂管数满足三次函数关系,单孔一点致裂方案能够实现增透促抽;致裂后增透促抽瓦斯效果显著,为安全高效抽采瓦斯提供了有效的技术支撑。Aiming at the problems of poor gas drainage effect and high risk in permeability improvement by explosives blasting in high gas and low permeability coal seam,through the combined methods of theoretical analysis and calculation,numerical simulation and field test,the principles and coal seam damage of liquid CO2 fracturing for permeability improvement in coal seam were studied,and the fracturing equivalent of liquid CO2 was calculated,then the geometric types and parameters of the key part,release tube,were simulated and optimized,finally,the influence of phase-transition fracturing points on the fracturing effect was studied. The results showed that CO2phase-transition fracturing enhances the fractures development and permeability of coal and rock seams through impacting and breaking the coal and rock by high pressure gas. The equivalent of 1 kg liquid CO2phase-transition fracturing blasting is equal to 398 kg TNT explosive. The optimal structure of the release tube is a hollow cylinder structure,of which the optimal length,diameter and pressure is 18 mm,24 mm and 276 MPa respectively. The influence radius of gas drainage presents a cubic function relationship with the amount of fracturing pipes. The single hole and one point fracturing scheme can achieve the permeability improvement and drainage promoting.The effect of permeability improvement and drainage promoting after fracturing is obvious,which provides effective technical support for safe and efficient gas drainage.

关 键 词：低透气煤层 增透促抽 相变致裂 致裂能量 释放管参数 

分 类 号：TD713[矿业工程—矿井通风与安全]