基于瓦斯自然涌出规律的有效抽采半径研究

Research on effective extraction radius based on natural gas emission law

为确定穿层钻孔有效抽采半径,提出基于钻孔瓦斯自然涌出规律的测定方法。利用COMSOL Multiphysics软件分析钻孔周围瓦斯流动规律;根据模拟结果及煤层瓦斯流动理论,建立钻孔瓦斯自然排放影响圈内瓦斯含量、瓦斯涌出量和残存瓦斯量之间的函数关系式,提出以钻孔瓦斯自然涌出有效影响半径代替抽采负压影响下的有效抽采半径;在鹤壁三矿、十矿和古汉山矿进行现场实测。结果表明:有效抽采半径内,瓦斯压力呈线性分布;受钻孔周围煤体蠕变卸压影响,瓦斯自然涌出具有明显的阶段性特征,确定的有效抽采半径最大可达4m,研究结果符合实际。

In order to determine the effective extraction radius of the boreholes through strata,a method based on the natural gas emission characteristics of boreholes was proposed. The gas flow law around boreholes was analyzed by COMSOL Multiphysics software. According to the simulation results and the theory of coalbed methane flow,a function relationship was established between gas content,gas emission and residual gas quantity in the gas natural discharge of borehole. It is proposed that the effective extraction radius under the influence of extraction negative pressure was replaced by that based on natural gas emission law of the borehole. Field measurements were carried out in Hebi No.3 Mine,No.10 Mine and Guhanshan Mine. The results show that the gas pressure is linearly distributed within the effective extraction radius,that the natural gas emission has obvious periodic characteristics under the influence of pressure relief due to creep deformation,and the effective extraction radius is up to 4 m,and that the research result conforms with the reality.