钻孔流量法在本煤层钻孔抽采半径考察中的应用

Study on Application of Borehole Flow Method in Investigation of Borehole Extraction Radius in Mining Coal Seam

为准确考察本煤层钻孔有效抽采半径,根据煤层瓦斯流动理论建立了钻孔瓦斯流量与时间的关系式,分析了在不同瓦斯赋存条件下进行试验考察的指标标准,并结合肥田煤矿为突出煤层开采的实际情况采用瓦斯含量和抽采率指标法确定抽采达标时间,最终得出抽采半径与抽采时间之间的相关关系为R=0. 7005lnt-2. 0749。考察结果表明:有效抽采半径随时间增加而增大,逐渐趋于极限有效抽采半径2m;抽采时间为37d、89d、168d、318d时对应的有效抽采半径为0. 5m、1m、1. 5m、2m。通过现场试验证明钻孔流量法可用于本煤层钻孔抽采半径考察。

In order to accurately investigate the effective extraction radius of mining coal seam borehole,the relationship between the gas flow rate of the borehole and the time was established based on the theory of gas flow in the coal seam. The index standard of experimental investigation under different gas occurrence conditions was analyzed. The extraction standard time t was determined using the gas content and extraction rate index method in combination with the actual situation of Feitian Coal Mine in order to highlight the coal seam mining. Finally,the correlation between the extraction radius r and the extraction time t was obtained as R = 0. 7005 lnt-2. 0749. The investigation results show that the effective extraction radius increases with time and gradually approaches the limit effective extraction radius of 2 m. When the extraction time is 37 d,89 d,168 d,318 d,the corresponding effective extraction radius is 0. 5 m,1 m,1. 5 m,2 m. The field test proves that the drilling flow method can be used to investigate the extraction radius of drilling holes in mining coal seam.