无人机频率域半航空电磁法三维反演  

3-D inversion of UAV semi-airborne electromagnetic method in frequency domain

作　　者：王堃鹏[1,2] 罗威 曹辉 王绪本[1] 蓝星[3] 段长生 WANG KunPeng;LUO Wei;CAO Hui;WANG XuBen;LAN Xing;DUAN ChangSheng(College of Geophysics,Chengdu University of Technology,Chengdu 610059,China;Chengdu Center,China Geological Survey,Chengdu 610081,China;Sichuan Metallurgical Geological Survey and Design Group Co.,Ltd.,Chengdu 610051,China;Ganzhongnan Institute of Geology and Mineral Exploration,Nanchang 330029,China)

机构地区：[1]成都理工大学地球物理学院,成都610059 [2]中国地质调查局成都地质调查中心,成都610081 [3]四川省冶勘设计集团有限公司,成都610051 [4]赣中南地质矿产勘查研究院,南昌330029

出　　处：《地球物理学报》2021年第5期1759-1773,共15页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(42004057,41974090);四川省科技计划(2021ZHCG0014);数学地质四川省重点实验室开放基金(scsxdz2018yb02)联合资助.

摘　　要：当前无人机频率域半航空电磁方法(SAEM)成为地球物理勘探中的新兴技术,该方法通过空中无人飞行器测量地面上单个或多个可控源的垂直磁场.本文为无人机频率域SAEM开发了三维反演程序,正演采用交错网格有限差分.由于无人机采集的数据量巨大,因此使用了有限内存拟牛顿法(LBFGS)实现快速的三维反演,以避免计算和存储巨大的灵敏度矩阵.为了提升无人机频率域SAEM的三维反演效果,本文进一步实现了无人机频率域SAEM与大地电磁(MT)的三维联合反演,并对联合反演实施了地震结构约束,结构约束采用交叉梯度法实现.MT可以增加勘探深度,而结构约束可以提高电磁法反演的分辨率.最后通过建立四个理论模型,证明了本文程序的有效性.The current semi-airborne electromagnetic method(SAEM)in the frequency domain of unmanned aerial vehicle(UAV)has become an emerging technology in geophysical exploration.This method measures the vertical magnetic field of a single or multiple controlled-sources on the ground through an UAV.In this paper,a three-dimensional(3D)inversion program is developed for the frequency domain SAEM of UAV,and the forward modeling uses staggered-grid finite difference.Due to the huge amount of data collected by the UAV,the limited-memory Broyden-Fletcher-Goldfarb-Shanno(LBFGS)method is used to achieve fast 3D inversion to avoid calculating and storing huge sensitivity matrices.In order to improve the 3D inversion results of UAV frequency domain SAEM,this paper further realizes the 3D joint inversion of UAV frequency domain SAEM and magnetotelluric(MT)and implements seismic structural constraints for the joint inversion.The structural constraints are realized by the cross-gradient method.MT can increase the depth of exploration,and structural constraints can improve the resolution of electromagnetic inversion.Finally,four theoretical models are established to prove the effectiveness of the program in this paper.

关 键 词：无人机 垂直磁场 大地电磁 LBFGS 交叉梯度 

分 类 号：P631[天文地球—地质矿产勘探]