余吾煤业瓦斯抽采钻孔合理间距研究

Research on reasonable spacing of gas drainage boreholes in Yuwu Coal Mine

瓦斯抽采钻孔间距的设计与钻孔瓦斯的高效抽采密切相关,采用单一的瓦斯流量法或压降法测定钻孔间距存在很大误差。为减小单一测定方法带来的误差,将瓦斯流量法与压降法进行结合,统一测定钻孔间距,提高钻孔间距布置的合理性。首先介绍了瓦斯流量法的测定原理,基于钻孔成孔时的影响范围在1 m左右,布置测定钻孔间距为2、3、4、5 m,得到不同预抽期时合理的钻孔间距,排除大于3 m的钻孔间距;其次,在流量法基础上,利用压降法测定钻孔间距,通过布置测压钻孔并借助origin处理数据,得到抽采半径与时间的对数关系,计算出预抽期为20、45、60、90 d合理的钻孔间距分别为1.5、2、2.5、2.8 m。

The design of borehole spacing in gas drainage is closely related to the efficient gas extraction in boreholes.There is a big error in determining the borehole spacing by using a single gas flow method or pressure drop method.To reduce the error caused by a single measurement method,this paper uniformly determined the hole spacing by combining the gas flow method and the pressure drop method,so as to improve the rationality of the drill hole spacing arrangement.Firstly,the measuring principle of gas flow method was introduced.Becausethe influence range of drilling hole is about 1 m,the hole spacing was designed as2 m,3 m,4 m and 5 m,the reasonable hole spacing in different pre-pumping period was obtained,and the hole spacing greater than 3 m was excluded.Secondly,on the basis of flow method,the borehole spacing was determined by pressure drop method.By arranging pressure measuring boreholes and processing data with the aid of origin,the logarithmic relationship between extraction radius and time was obtained.It was calculated that the reasonable borehole spacing of 20 d,45 d,60 d and 90 d was 1.5 m,2.0 m,2.5 m and 2.8 m respectively.