天然气钻井影响下综采工作面底板破坏特征分析

Floor failure characteristics of fully mechanized mining face under influence of natural gas drilling

废弃天然气钻井的存在会导致工作面回采过程中底板破坏特征发生变化,同时采动也会造成废弃天然气钻井密封结构发生破坏,增加天然气逸散到工作面的可能性。针对青龙寺煤矿5-20111工作面回采过废弃天然气钻井开展数值模拟研究,分析在天然气钻井影响下工作面底板竖向位移和底板破坏深度的变化规律,探究采动对废弃天然气钻井密封结构的影响规律。研究结果表明,在天然气钻井影响下5-20111综采工作面底板最大竖向位移为40mm,底板最大扰动破坏深度约为16m。5-20111工作面开采过程中,工作面底板下方废弃天然气钻井及周边1m范围内岩体的最大破坏深度约为80m,在此范围内钻井周边0.3m范围内的岩体会发生破坏而出现逸气通道。

The existence of abandoned natural gas drilling will lead to changes in the failure characteristics of the floor during the mining process of the working face,and mining will also cause the failure of the sealing structure of the abandoned natural gas drilling,increasing the possibility of natural gas escaping to the working face.In this paper,a numerical simulation study is carried out in the abandoned natural gas drilling on the 5-20111 working face of Qinglongsi Coal Mine.The variation law of vertical displacement and failure depth of floor under the influence of natural gas drilling was analyzed.The influence of mining on the sealing structure of abandoned natural gas drilling was studied.The research results show that under the influence of natural gas drilling,the maximum vertical displacement of the floor of 5-20111 fully mechanized mining face is 40 mm,and the maximum disturbance failure depth of the floor is about 16 m.In the mining process of the working face,under the working face floor,the maximum rock failure depth of the abandoned natural gas well and within 1 m of the surrounding rock mass is about 80 m.Within this 80 m of range,the rock mass within 0.3 m of the drilling well will be damaged,leading to the appearance of air escape channel.