阳泉七尺煤层瓦斯抽放参数计算

CALCULATION OF GAS DRAINAGE PARAMETERS FOR QI CHI COAL SEAM IN YANGQUAN

本文以达西定律为基础,建立了煤层瓦斯流动方程,并利用电子计算机进行了数值求解。通过对阳泉七尺煤层现场实测数据的整理分析和模拟计算,探讨了阳泉七尺煤层的瓦斯抽放参数计算问题,根据模拟计算结果,得出抽放负压对瓦斯涌出量的影响较小,煤层瓦斯抽放率主要与钻孔间距、钻孔直径及抽放时间有关,其关系符合文中式(19),该式可作为阳泉七尺煤层瓦斯抽放设计的依据。由该式还可以得出,延长抽放时间对于提高瓦斯抽放率亦具有不可忽视的作用;当抽放时间受到限制时,要想提高瓦斯抽放率,与其增大钻孔直径,不如减小钻孔间距来得合算。

This paper has established a gas flow equation based on Darcy Law,and solu- tion of values is made by using a computer.Based on collation and analysis of data obtained in field observations made in Qi Chi Seam in Yangquan and on simulation calculation,the paper discusses problems related to calculation of param- eters for gas drainage from Qi Chi Seam in Yangquan.According to the calcu- lated results from simulation we have come to a conclusion that the suction pres- sure has little effect on gas emission,and that gas drainage rate is mainly related to borehole spacing,borehole diameter and time of gas drainage.And its relation is in conformity with equation(19)described in the paper,which can be regarded as a criterion for design of Qi Chi Seam gas drainage system.From the equa- tion we can see the considerable effect of lengthening the time duration on the rate of gas drainage.In case time of gas drainage is limited,we would rather decrease borehole spacing than to increase the diameter of borehole in order to improve the rate of gas drainage.