基于CDI和拟二维反演的时间域航空电磁数据级联解释方法  

A cascade interpretation method based on CDI and quasi-2D inversion for airborne time-domain electromagnetic data

作　　者：王键 陆从德[2] 张澎 WANG Jian;LU Congde;ZHANG Peng(Chengdu University of Technology,College of Geophysics,Chengdu 610059,China;Chengdu University of Technology,College of Mechanical and Electrical Engineering,Chengdu 610059,China;Chengdu University of Technology,College of Computer and Network Security(Oxford Brooks College),Chengdu 610059,China;Key Lab of Earth Exploration and Information Technology of Ministry of Education(Chengdu University of Technology),Chengdu 610059,China)

机构地区：[1]成都理工大学地球物理学院,成都610059 [2]成都理工大学机电工程学院,成都610059 [3]成都理工大学计算机与网络安全学院(牛津布鲁克斯学院),成都610059 [4]成都理工大学地球探测与信息技术教育部重点实验室,成都610059

出　　处：《物探化探计算技术》2023年第4期463-477,共15页Computing Techniques For Geophysical and Geochemical Exploration

基　　金：国家重点研发计划(2017YFC0601806)。

摘　　要：时间域航空电磁法(ATEM)是一种具有大面积探测,探测速度快、相对成本较低、受地形地貌影响较小等优点的地球物理方法。由于航空电磁数据量巨大,三维反演成本太大,目前主要使用一维反演或者拟二维反演方法来进行解释。对于航空电磁探测而言,大面积探测区域和复杂地形条件使得研究人员很难获取到勘探区域的地质信息,因此反演时选取初始模型变得很困难。而电导率-深度成像(CDI)无需建立初始模型,即可快速获得地下介质的大致电性分布情况。因此CDI结果可以用来作为反演的初始模型,应对缺少地质信息的区域。本次研究中,提出CDI与拟二维反演的级联解释方法。首先使用CDI方法来近似估计地下介质的电导率和深度;其次在此基础上建立反演的初始模型;最后采用横向约束反演(LCI)方法对ATEM数据进行反演。通过对理论数据和实测数据的实验得出,CDI与拟二维反演的级联解释方法能够在获得较好的反演结果的同时减少计算时间。Airborne time-domain electromagnetic method(ATEM)is a geophysical method with the advantages of large-area detection,fast detection speed,relatively low cost,and less impact on topography.Due to the considerable amount of airborne electromagnetic data,the cost of 3D inversion is too high.Currently,1D inversion or quasi-2D inversion methods are mainly used for interpretation.For aerial electromagnetic detection,the large detection area and complex terrain conditions make it difficult for researchers to obtain the geological information of the exploration area,so it is challenging to select the initial model during inversion.Conductivity depth imaging(CDI)can quickly obtain a large electrical distribution of subsurface media without building an initial model.Therefore,the CDI results can be used as an initial inverted model in a Greenfield area.This study proposes a cascade interpretation method of CDI and quasi-2D inversion.First,the CDI method is used to approximate the conductivity and depth of the subsurface medium.Secondly,the initial model of inversion is established on this basis.Finally,the laterally constrained inversion(LCI)method is used to invert the ATEM data.Experiments on theoretical data and measured data conclude that the cascaded interpretation method of CDI and quasi-2D inversion can obtain better inversion results and reduce computation time.

关 键 词：时间域航空电磁法 电导率-深度成像 横向约束反演 初始模型 

分 类 号：P631.3[天文地球—地质矿产勘探]