钻孔循环注热煤层巷道围岩水渗流场变化规律  

Variation law of water seepage field in roadway surrounding rock of drilling and circulating hot coal seam injection

作　　者：李茂林 LI Maolin(Xishan Coal Electricity(Group)Co.,Ltd.,Taiyuan 030053,China)

机构地区：[1]西山煤电(集团)有限责任公司,山西太原030053

出　　处：《煤炭科技》2024年第5期12-18,23,共8页Coal Science & Technology Magazine

摘　　要：基于渗流力学、传热学等理论,建立了流热耦合数值计算模型,针对不同注热钻孔封孔深度条件下,采用单一钻孔间歇注热及相邻钻孔交替注热的2种方式进行注热时,煤层巷道围岩水渗流场变化规律开展数值模拟研究。研究表明,采用单一钻孔循环注热时,随着注热循环次数增加,煤层流体压力由钻孔向两侧逐渐传递。在抽采过程中,煤层流体压力峰值转移到钻孔两侧,在靠近巷帮的区域,高流体压力区域随着封孔深度的减小而增加。采用相邻钻孔交替注热时,巷道围岩压力峰值在两个钻孔处交替出现。随着注热次数的增加,升压范围不断扩大;注热钻孔的间距越大,煤层中流体高压力区域范围越大。随着封孔深度的减小,煤层中应力集中区内的高流体压力区域增大。巷道围岩热水泄漏风险随着注热循环周期的增长、封孔深度的增加而减小;在相同封孔深度与注热循环周期条件下,热水泄漏风险大小依次为:单一钻孔循环注热<相邻钻孔交替注热(间距2 m)<相邻钻孔交替注热(间距4 m)。Based on the theories of seepage mechanics and heat transfer,a numerical calculation model of fluid-heat coupling was established.Numerical simulation research was conducted on the changes in the water seepage field of surrounding rock in coal seam roadways under different sealing depths of heat injection drilling,using two methods of intermittent hot injection between single drilling and alternating hot injection between adjacent drilling for hot injection.Research shows that when using a single drilling cycle for heat injection,as the number of heat injection cycles increases,the fluid pressure in the coal seam gradually transfers from the drilling to both sides.In the process of extraction,the peak value of coal seam fluid pressure is transferred to both sides of the drilling.In the area near the roadway wall,the high fluid pressure area increases with the decrease of the hole sealing depth.When adjacent drilling are used for alternating heat injection,the peak pressure of the surrounding rock in the roadway appears alternately at the two drilling positions.As the number of heat injections increases,the range of pressure rise continues to expand;the larger the spacing of heat injection drilling,the larger the range of high fluid pressure areas in the coal seam.As the depth of sealing decreases,the high fluid pressure area within the stress concentration zone in the coal seam increases.The risk of hot water leakage in the surrounding rock of the roadway decreases with the increase of the injection cycle and the depth of the sealing hole.The risk of hot water leakage under the same sealing depth and injection cycle conditions is in the following order:single drilling cycle heat injection<alternating injection of heat between adjacent drilling(with a spacing of 2 meters)<alternating injection of heat between adjacent drilling(with a spacing of 4 meters).

关 键 词：煤层气 注热强化煤层气抽采 巷道围岩 水渗流场 

分 类 号：TD311[矿业工程—矿井建设]