基于流固耦合的瓦斯抽采有效半径的数值模拟

Numerical Simulation of Effective Radius of Gas Drainage Based on Fluid-solid Coupling Model

瓦斯抽采有效半径的准确确定关系到钻孔布置参数的设定、矿井抽采的设计以及矿井的安全生产等诸多方面。本文通过建立流固耦合模型,模拟计算得到不同时间钻孔附近瓦斯压力变化曲线,并总结出瓦斯有效半径的变化趋势;通过参数化扫描对不同抽采负压进行模拟,得到60 d时瓦斯压力分布曲线,发现抽采负压的大小对有效半径的影响有限。通过分析,认为井下钻孔抽采瓦斯存在一定缺陷:钻孔附近由于应力集中,降低了煤层渗透率,不利于提高瓦斯抽采效率。

The accurate determination of effective radius of gas extraction relates to the setting of drilling parameters, the design of gas drainage and the safety production of coalmine. By the establishment of fluid-solid coupling model, the gas pressure curve near the borehole at different time is simulated and the changing trend of the effective radius of the gas is summarized. The 60 days gas pressure distributed curve chart is obtained by parameterized scanning of different negative pressure under simulation condition, it shows that the affect of negative pressure to effective radius are very limited. The analysis shows that underground borehole gas drainage has a certain defects, the stress concentration near the borehole reduces the permeability＇ of the coal seam and is not conducive to improving the gas extraction efficiency.