煤体复电性频散响应实验研究

Experimental study on the frequency dispersion response of composite electrical properties of coal

为研究煤体复电性频散响应特征,实测不同测量面积,不同方向煤体的复电阻实部R和虚部X,分析其频散特征,并用不同经典模型进行数据反演对比。结果表明:任意方向煤体的复电参数(R、X的绝对值)与测量面积成反比,频散曲线的特征频率点不发生偏移,X频散度随测量面积增大而减小;相同测量面积,不同方向煤体的复电性频散响应不同,复电频散曲线发生偏移,平行层理方向煤体X的频散度大于垂直层理方向;Debye模型与Cole-Cole模型对煤体复电性频散曲线均可高精度拟合,但前者模型参数精简,物理意义明确,与煤体复电频散曲线开合情况吻合度较高。本研究可为复电性评价法监测煤层裂隙发育及评价煤层渗透率提供实验基础。

In order to study the characteristics of frequency dispersion response of the composite electrical properties of coal,the real part R and imaginary part X of the composite resistance of coal body at different direction in different measured areas were measured,the frequency dispersion characteristics were analyzed,different classical models were used to conduct data inversion and comparison.The results show that the composite electrical property parameters(absolute value of R and X)of coal are inversely proportional to the measured area,the characteristic frequency points are not offset,the X-frequency divergence decreases with the increase of measurement area;for the same measured area,the frequency dispersion response of the composite electrical property of coal at different direction is different,the frequency dispersion of the composite electrical curve deviates,the frequency dispersion of X parallel to coal bedding is greater than that vertical to bedding;Debye model and Cole-Cole model can be used to fit the dispersion curve of the composite electrical property of coal,but the former model has simple parameters and clear physical meaning,and coincides well the composite electrical frequency dispersion curve of coal.This study provides an experimental basis for monitoring the seam crack and evaluating coal seam permeability by the evaluation method of the composite electrical property.