中心回线瞬变电磁测深法快速电阻率成像方法及应用

A rapid resistivity imaging method for central loop transient electromagnetic sounding and its application

利用导电全空间与均匀半空间中心回线源和磁偶极子在阶跃电流激发下磁场公式和扩散速度的定义 ,导出了不同条件下瞬变场的扩散速度公式。在此基础之上 ,引入瞬变电磁测深全区视电阻率定义数值计算方法 ,给出了电阻率成像的一阶与二阶近似公式 ,从而建立了一套中心回线瞬变电磁测深快速电阻率成像方法。模型检验结果、实测剖面电阻率成像以及对大地电磁测深视电阻率曲线进行静偏移校正效果均良好 ,说明该方法是可行的、有效的。

We developed a fast resistivity imaging method for central loop transient electromagnetic sounding(TEM).Firstly,diffusion velocities were derived on the basis of propagation features of transient electromagnetic filed in full conductive space and half conductive space.Secondly,the all time apparent resistivity curve was calculated with numerical method after studying the half space function of vertical component of magnetic field.And finally,imaging formulas were given with diffusion velocity and all time apparent resistivity.The model tests and field example testified the validity of imaging for geo-electrical structure and electromagnetic sounding(MT)correction.