瓦斯抽采有效半径影响因素的数值模拟

Numerical Simulation of the Influencing Factors of Effective Radius for Gas Drainage

采用Fluent数值模拟软件对钻孔周围煤体瓦斯渗流规律进行了模拟,包括煤层渗透率、煤层瓦斯压力、钻孔直径、抽采负压及抽采时间对抽采半径的影响。得出结论:煤层渗透率是决定抽采半径及钻孔抽采能力的决定性因素,其次是抽采时间与钻孔直径;抽采负压与煤层原始瓦斯压力为次要因素,对抽采半径及抽采量影响很小。因此,减少钻孔施工量、提高抽采量的最有效方法就是提高煤层渗透率,如采用水力割缝、水力压裂、深孔松动爆破等措施,以及增大钻孔直径等。

The seepage law of the gas around the drill holes is simulated on coal with Fluent soft. It includes the influences on the radius of the extraction which are caused by the permeability of coal seam, the gas pressure of coal seam, the diameter of the hole and negative pressure and time of gas drainage. The results show that the permeability of coal seam decides on the radius and capacity of the extraction, then it is time of gas drainage and the diameter of the hole. The last factors are negative pressure of gas drainage and the original gas pressure of coal seam. So the most effective method of improving permeability of coal seam is reducing the drilling work and improving the quantity of extraction, such as taking hydraulic slotting, hydraulic fracturing, blasting deep loose hole and increasing the drilling diameter.