三维时间域航空电磁任意各向异性正演模拟（英文）

发布时间：2018-09-10 18:22

【摘要】：在自然界中地层会呈现出各向异性特征,各向异性介质的研究有助于资料解释和认识地球动力学的过程,但当前数据处理中多数使用各向同性理论解释各向异性构造,因而对电磁资料解释造成了一定的偏差。当前,时间域航空电磁法关于各向异性的解释仍局限于一维情况,且相应的三维数值模拟也正处于研究中,因此本文针对任意各向异性介质中三维时间域航空电磁法进行正演模拟。将各向同性介质的电导率经过坐标旋转后,得到任意各向异性介质的电导率张量,将其引入到麦克斯韦方程组中,采用矢量有限元法的规则网格对求解区域进行剖分,利用直接求解器对总体合成的线性方程组进行求解。通过与解析解对比,验证了算法的精确性和可行性;同时与各向同性情况进行对比,通过响应的分布特征及幅值变化分析任意各向异性对三维时间域航空电磁响应的影响,得出在不同情况下各向异性对时间域航空电磁响应的影响情况存在较大差异。
[Abstract]:The study of anisotropic media is helpful to the interpretation of data and the process of geodynamics. However, the isotropic theory is used to explain anisotropic structures in current data processing. Therefore, the interpretation of electromagnetic data caused a certain deviation. At present, the interpretation of anisotropy in time-domain aero-electromagnetic method is still confined to one-dimensional case, and the corresponding three-dimensional numerical simulation is also under study. Therefore, in this paper, the forward modeling of three dimensional time domain aero-electromagnetic method in arbitrary anisotropic media is carried out. The conductivity of the isotropic medium is rotated in coordinates, and the conductivity of any anisotropic medium is obtained by Zhang Liang, which is introduced into Maxwell's equations. The regular mesh of the vector finite element method is used to divide the solution region. A direct solver is used to solve the system of linear equations. The accuracy and feasibility of the algorithm are verified by comparing with the analytical solution, and compared with the isotropic case, the influence of arbitrary anisotropy on the three-dimensional time-domain aero-electromagnetic response is analyzed by analyzing the distribution characteristics and amplitude variation of the response. It is concluded that the influence of anisotropy on time domain aeronautical electromagnetic response is quite different in different cases.
【作者单位】：中国地质科学院地球物理地球化学勘查研究所;国土资源部地球物理电磁法探测技术重点实验室;吉林大学地球探测科学与技术学院;
【基金】：financially supported by National Nonprofit institute Research Grant of IGGE(Nos.AS2017J06,AS2017Y04,and AS2016J10) Survey on coastal area for airborne magnetic method of UNV in Jiangsu(No.DD20160151-03) Key National Research Project of China(No.2017YFC0601900) Key Program of National Natural Science Foundation of China(No.41530320) Natural Science Foundation(No.41274121) China Natural Science Foundation for Young Scientists(No.41404093)
【分类号】：P631.325

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