复杂异常体模型下的三维MT倾子正演模拟  

Forward modeling of MT tipper based on 3D complex anomalous body model

作　　者：田郁 乐彪 TIAN Yu;YUE Biao(Guizhou Geological Survey,Guiyang 550000,China;Guizhou Engineering Research Center for Geological Development and Application,Guiyang 550000,China;Zhengye Engineering&Investment Incorporation Ltd.,Guiyang 550000,China)

机构地区：[1]贵州省地质调查院,贵州贵阳550000 [2]贵州省地质物探开发应用工程技术研究中心,贵州贵阳550000 [3]贵州正业工程技术投资有限公司,贵州贵阳550000

出　　处：《物探与化探》2021年第4期1021-1029,共9页Geophysical and Geochemical Exploration

基　　金：贵州省地质矿产勘查开发局地质科研项目“大地电磁倾子特征研究及其在地球物理解释中的应用”(黔地矿科合[2020]28);贵州省地质物探开发应用工程技术研究中心项目(黔科合[2016]平台人才5401)。

摘　　要：倾子对地下构造的电性不均匀性反映较灵敏,在大地电磁资料解释中可作为复杂构造的表征。本文在三维大地电磁有限元正演模拟的基础上,根据倾子定义推导出三维倾子计算公式,构建复杂异常体模型进行三维倾子正演模拟。研究表明针对多个异常体模型,倾子的各个分量均能反映出异常体的空间位置,倾子不仅能准确地反映出单个异常体的边界,且对多个异常体的边界反映也较准确,其中对低阻异常体反映较高阻异常体敏感,由此进一步了解了三维倾子资料特征和规律,为倾子资料的应用提供了理论依据。Tipper is very sensitive to the lateral inhomogeneity of the geoelectric structure and can be used to characterize the complex structure.In this paper,based on the three-dimensional complex anomalous body model of magnetotelluric sounding,the formula for calculating the three-dimensional tipper is derived according to the definition of the dump,and three-dimensional anomalous volume models with different combinations are constructed for forward modeling.Forward modeling studies show that the tipper data better reflect the abnormal body boundary,and it is also more accurate to reflect the boundary of several abnormal bodies,whereas the low resistivity body sensitively reflects a high resistance abnormal body.The study of tipper data further explains the characteristics and laws of tipper data and provides a theoretical basis for the application of tipper data.

关 键 词：大地电磁测深法 倾子 三维正演模拟 复杂异常体模型 

分 类 号：P631[天文地球—地质矿产勘探]