各向异性激发极化层状介质可控源音频大地电磁响应模拟研究  

Synthesis modeling of CSAMT responses in multi-layer earth with anisotropic induced polarized effect

作　　者：刘卫强 林品荣[3] 严加永[2] 陈家坤[1] 杨良勇 LIU WeiQiang;LIN PinRong;YAN JiaYong;CHEN JiaKun;YANG LiangYong(College of Geophysics,China University of Petroleum-Beijing(CUP),Beijing 102249,China;Chinese Academy of Geological Science,Deep Earth Exploration Center,Beijing 100037,China;Institute of Geophysical and Geochemical Exploration of Chinese Academy of Geological Science,Key Laboratory of Geophysical Electromagnetic Probing Technologies of Ministry of Natural Resources,Langfang 065000,China;Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China)

机构地区：[1]中国石油大学(北京)地球物理学院,北京102249 [2]中国地质科学院地球深部探测中心,北京100037 [3]中国地质科学院地球物理地球化学勘查研究所,自然资源部地球物理电磁法探测技术重点实验室,廊坊065000 [4]中国科学院地质与地球物理研究所,北京100029

出　　处：《地球物理学进展》2021年第6期2503-2518,共16页Progress in Geophysics

基　　金：中国石油大学(北京)科研基金(2462020YJRC010,2462020YXZZ005);中国博士后科学基金(2021M693492);国家重点研发计划(2018YFE0208300);自然资源部重点实验室开放课题(KLGEPT201908)联合资助。

摘　　要：在自然界中,电性各向异性和激发极化效应是岩矿石客观存在的物理性质,传统的电磁勘探方法通常将地下介质简化为不含激电效应的各向同性电阻率模型,不利于实现多参数精细探测.本文开展了考虑介质各向异性激发极化效应的层状大地可控源音频大地电磁响应数值模拟研究.首先提出了各向异性的Cole-Cole模型,然后将各向异性复电阻率代入电偶源激发各向异性地层电磁场响应公式,实现了地面电磁场各分量的正演计算,进一步分析了各参数对地表电磁场响应及全区视电阻率的影响.在正演模拟的基础上,提出了一种基于粒子群最优化算法的反演方法.通过对地下模型参数取对数,并对各参数取值范围进行约束,可以依次反演得到各地层在平行层理与垂直层理两个方向上的电阻率、充电率及时间常数.本文的研究表明,当测区中浅部存在各向异性激发极化地层时,电磁响应会受到较大影响,全局最优化反演可以获得地下介质的电性多参数信息,更好地拟合观测数据.In practical,electrical anisotropy and Induced Polarization(IP)are objective physical properties of rocks and ores.Traditional electromagnetic exploration methods usually simplify underground medium to isotropic resistivity model without IP effect,which is not conducive to the realization of multi-parameter detailed detection.In this paper,the numerical simulation of Controlled-Source Audio Magnetotelluric(CSAMT)responses in layered earth with anisotropic induced polarized effect is carried out.Firstly,the anisotropic Cole-Cole model is proposed.Then,the anisotropic complex resistivity is substituted into the formula of anisotropic electromagnetic field responses to forward each component of the ground electromagnetic field.We further analyze the influence of each parameter on the surface electromagnetic field response and the full-field apparent resistivity.Based on the forward simulation,an inversion method based on particle swarm optimization(PSO)algorithm is proposed.By taking logarithm of the parameters in underground model and restricting the value range of each parameter,the resistivity,charging rate and time constant of each layer in two directions of parallel and vertical bedding can be obtained successively by inversion.The research in this paper shows that the electromagnetic responses will be greatly affected when there is an anisotropic induced polarized layer in the shallow and middle part of the survey area.The global optimization inversion can help to obtain the multi-parameter electrical information of the properties of the underground medium to further fit the observed data.

关 键 词：可控源音频大地电磁 激发极化效应 电性各向异性 层状介质正演 粒子群优化 

分 类 号：P631[天文地球—地质矿产勘探]