平凉台井下地电阻率观测影响系数分析

Sensitivity Coefficient Analysis of the Deep-well Apparent Resistivity Measurement of the Pingliang Seismic Station

摘要:

根据地电阻率影响系数理论，以平凉台4层电性结构为例，分析了井下对称四极地电阻率观测影响系数随深度和极距的变化。结果表明：对于固定的观测极距，影响系数与电极埋深之间的关系复杂；通过计算各层影响系数的大小，认为平凉台井下观测对地表及浅层干扰有较好的抑制作用，其分析结果可为在类似台址电性结构中实施井下地电阻率观测时选择电极埋深和供电极距提供参考。

Abstract:

Based on geo-electric resistivity sensitivity coefficient,we take the four layer electrical structure of the Pingliang station as an example to analyze the distributions of sensitivity coefficients with the spacing and depth of the electrodes when the Schlumberger arrays are used in the resistivity measurement. The results show that for a fixed Schlumberger array,sensitivity coefficients display complex variations with the increase of electrode depth. By calculating the size of the sensitivity coefficient of each layer,we find that the well observations of the Pingliang station has good inhibition to surface and shallow interference of deep well geo-electric resistivity. The result of the analysis can be references for the selection of electrode depths and power supply distance in the implementation of deep well geo-electric resistivity observation for similar stations.