任意各向异性介质三维有限元航空电磁响应模拟  

3D Vector Finite-Element Airborne Electromagnetic Modelling in an Arbitrary Anisotropic Medium

作　　者：曾昭发[1,2] 霍祉君 李文奔 李静 赵雪宇[1,2] 何荣钦[1,2] Zeng Zhaofa;Huo Zhijun;Li Wenben;Li Jing;Zhao Xueyu;He Rongqin(College of GeoExploration Science and Technology, Jilin University, Changchun 130026, China;Key Laboratory of Applied Geophysics, Ministry of Land and Resources of PRC, Changchun 130026, China;College of Information Engineering, Hebei GEO University, Shijiazhuang 050031, China)

机构地区：[1]吉林大学地球探测科学与技术学院,长春130026 [2]国土资源部应用地球物理重点实验室,长春130026 [3]河北地质大学信息工程学院,石家庄050031

出　　处：《吉林大学学报（地球科学版）》2018年第2期433-444,共12页Journal of Jilin University：Earth Science Edition

基　　金：国家重点专项子课题(2016YFC060110402);国家自然科学基金项目(41504083);中国博士后科学基金项目(2015M571366)~~

摘　　要：在航空电磁探测方法应用中,地下探测环境复杂,地下介质物性参数存在各向异性特征。如果采用常规各向同性介质模型,在资料解释过程中会产生严重的偏差。本文基于矢量有限元法开展三维任意各向异性频率域航空电磁响应模拟计算研究。首先,将总场分解成一次场和二次场,对空气介质的均匀全空间进行一次场解析计算,同时利用矢量有限元法对二次电场的双旋度方程进行求解。为提高求解速度,采用共享内存直接求解器PARDISO对大规模稀疏矩阵并行计算,大大提高了三维模型的计算速度。之后开展了4种典型目标模型的三维各向异性介质模拟:围岩各向同性-目标体各向异性(绕z轴旋转)模型;围岩各向同性-目标体各向异性(绕x轴旋转)模型;围岩各向异性-目标体各向异性(绕z轴旋转)模型;围岩各向异性-目标体各向异性(绕x轴旋转)模型。对比分析了不同模型在不同旋转角度情况下,磁场实虚分量的变化特征,进而总结了各向异性参数对航空电磁响应的影响规律和识别方法。In the application of airborne electromagnetic detecting method,underground detection environment is complex,and the physical parameters of underground media are anisotropic.If we use the conventional model of isotropic medium,serious deviations will occur during the data interpretation.This paper presents three-dimensional frequency-domain airborne electromagnetic modeling in an arbitrary anisotropic medium based on the vector finite element method.By decomposing the total field into primary and secondary fields,the uniform space of the air medium is subjected to the analytic calculation of the primary field,and the vector finite element method is used to solve the double-rotation equation of the secondary electric field.The parallel solution of the large-scale sparse matrix is calculated by using the shared-memory direct solver PARDISO,so that the3D model calculation is greatly speeded up.Then the3D anisotropic media simulations of four typical target-models are carried out,including isotropic rock-anisotropic target(rotate around the z axis)model,isotropic rock-anisotropic target(rotate around x axis)model,isotropic rock-anisotropic target(rotate around z axis)model,and anisotropic rock-anisotropic target rotate(around x axis)model.The change characteristics of the real and imaginary components of the magnetic field under different rotating angles in different models are analyzed and compared,and the influence law and identification method of the anisotropic parameters in airborne electromagnetic response are summarized.The research can provide a reference for the accurate interpretation and inversion of the airborne electromagnetic data.

关 键 词：频率域航空电磁法 矢量有限元法 任意各向异性 

分 类 号：P631.1[天文地球—地质矿产勘探]