瞬变电磁法三维问题正演及激电效应特征研究

THE RESEARCH ON THE 3D TDEM MODELING AND IP EFFECT

利用并矢格林函数理论和积分方程方法计算两层大地中三维异常体的频率域电磁响应，并利用反余弦变换方法将其转换为时间域电磁响应．为了解释时间域电磁响应晚期段经常出现的场值变号现象，将描述电阻率频散特征的Ｃｏｌｅ－Ｃｏｌｅ模型引入到正演计算之中．计算表明，时间域电磁法的激电效应（ＩＰ）特征不仅受异常体的激电及电阻率参数的影响，而且受异常体的几何参数影响．

The FDEM responses of 3D body are calculated by integral equation method, which can be changed into TDEM responses by inverse cosine tranform. To explain the sign reversals of TDEM responses in late time stage, Cole-Cole model which describes the character of frequency-diversity of resistivity of polarizable body are introduced into the direct calculation. It has been shown that IP effects on TDEM field are influenced by the the geometric, electrical and IP parameters.