水平电偶极源层状模型垂直磁场全区视电阻率计算方法  

The calculation method of whole zone apparent resistivity of vertical magnetic field on the surface of layered model excited by horizontal electric dipole source

作　　者：伏海涛 罗维斌 丁志军 余其林 张世宽 FU Hai-Tao;LUO Wei-Bin;DING Zhi-Jun;YU Qi-Lin;ZHANG Shi-Kuan(Gansu Nonferrous Geological Survey Institute,Lanzhou 730000,China)

机构地区：[1]甘肃省有色地质调查院

出　　处：《物探与化探》2019年第6期1309-1319,共11页Geophysical and Geochemical Exploration

基　　金：国家自然科学基金项目“相关辨识技术在谱激电中的应用研究”(41374185);中国地震局地震科技星火计划(XH18046)联合资助

摘　　要：利用水平电偶极源层状模型电磁场公式系统计算了不同收发距、不同层状地电模型的电磁场分量,给出了由循环互相关法辨识出频率响应,并计算全区视电阻率的方法。利用水平电场Ex分量和垂直磁场Hz分量计算了全区视电阻率,与层状模型大地电磁测深卡尼亚视电阻率和可控源音频大地电磁测深卡尼亚视电阻率进行比较,水平电场Ex分量和垂直磁场Hz分量全区视电阻率均能很好地反映出地电特征,且垂直磁场Hz分量全区视电阻率与层状模型大地电磁测深卡尼亚电阻率在低频段有相似的频率响应特征。对于大埋深基底,Hz分量全区视电阻率在小收发距条件下就能有较好的响应。垂直磁场分量进入近区的频率低于水平电场进入近区的频率,更有利于在小收发距条件下进行大深度勘探。Using the electromagnetic field formula of horizontal electric dipole source on the surface of layered model,the authors cal?culate electromagnetic field components of different transmitting and receiving distances and different layered geoelectric models system?atically.The method for identifying frequency response by circular cross?correlation method and calculating the whole zone apparent re?sistivity is given.The apparent resistivity of the whole zone is calculated by using the Ex component of horizontal electric field and the Hz component of vertical magnetic field.Compared with the Cagniard apparent resistivity of layered model of magnetotelluric sounding and the Cagniard apparent resistivity of controlled source audio magnetotelluric sounding,the whole zone apparent resistivity of Ex com?ponent of horizontal electric field and the Hz component of vertical magnetic field can well reflect the geoelectric characteristics.Moreo?ver,the whole zone apparent resistivity of the vertical magnetic field with the Hz component has similar frequency response characteris?tics with the Cagniard resistivity of the layered model of magnetotelluric sounding in low frequency band.As for deep buried basement,the whole zone apparent resistivity of the Hz component can respond well under the condition of small transceiver distance.The frequen?cy of the vertical magnetic field component entering the near zone is lower than that of the horizontal electric field entering the near zone,which proves the proposed means is more conducive to deep exploration under the condition of small transceiver distance.

关 键 词：水平电偶极源 层状模型 垂直磁场 水平电场 全区视电阻率 

分 类 号：P631[天文地球—地质矿产勘探]