发射电流波形对瞬变电磁一维正反演的影响  

Effect of Transmitter Waveform on 1D Modeling and Inversion of Transient Electromagnetic Method Data

作　　者：王胜涛 林昌洪[1] 王旭东 WANG Shengtao;LIN Changhong;WANG Xudong(School of Geophysics and Information Technology,China University of Geosciences,Beijing 100083,China)

机构地区：[1]中国地质大学(北京)地球物理与信息技术学院,北京100083

出　　处：《现代地质》2023年第1期99-106,共8页Geoscience

基　　金：国家自然科学基金项目(41874159)。

摘　　要：本研究实现了考虑发射电流波形的瞬变电磁一维正反演算法。正演采用矩形回线源,通过Duhamel积分计算梯形波的感应电压;反演采用Occam反演方案,得到一个光滑的层状反演结果模型。理论模型合成算例的计算结果表明:上升沿时间、持续时间和下降沿时间不同程度地影响了垂直磁感应强度对时间的偏导数(dB/dt)响应以及电阻率反演结果。理论模型的正演结果显示,上升沿时间、持续时间和下降沿时间分别主要影响晚期、中晚期和早期的瞬变电磁响应,并且取值越大影响越大。理论模型合成数据的反演算例显示,不同上升沿时间对反演结果几乎没有影响,而下降沿时间和持续时间分别影响浅部和深部的反演结果。We have developed a 1D modeling and inversion algorithm for transient electromagnetic method(TEM)data with transmitter waveform.The source is a horizontal rectangular loop for the implementation.Through the Duhamel integral,the step response was converted to the response generated by the trapezoidal waveform.In the inversion,the Occam strategy is adopted to obtain a smooth layered model.The synthetic examples show that the time derivatives of the vertical magnetic fields,dB/dt,and the inversion results are distorted to different extents by the turn-on,steady and turn-off times.The investigated model response shows that the turn-on,steady,and turn-off times mainly affect the TEM data at late,intermediate-late,and early gate times,respectively.Furthermore,the distortions become greater with increasing durations of the turn-on,steady and turn-off times.Inversion results of the synthetic data indicate that the turn-on times have only minor influence on the inversion results,whilst the turn-off and steady times affect the inversion results of the shallow and deep parts,respectively.

关 键 词：瞬变电磁 发射波形 一维正反演 

分 类 号：P631[天文地球—地质矿产勘探]