二维各向异性介质海洋可控源电磁场反演中灵敏度计算分析  

Analysis of sensitivity calculations in the inversion of marine controlled source electromagnetic fields in two-dimensional anisotropic media

作　　者：叶益信 胡双贵 YE YiXin;HU ShuangGui(School of Resources and Geosciences,China University of Mining and Technology,Xuzhou 221116,China)

机构地区：[1]中国矿业大学资源与地球科学学院,徐州221116

出　　处：《地球物理学进展》2024年第4期1639-1647,共9页Progress in Geophysics

基　　金：国家自然科学基金项目(42274104)资助。

摘　　要：灵敏度的计算是海洋可控源电磁数据线性反演中的关键一环,决定了电磁数据反演的质量和效率,因此有必要对灵敏度计算进行检验和分析.本文推导了频率域可控源电磁2.5维反演中灵敏度的计算公式,采用自适应非结构有限元算法计算电磁正演响应,采用伴随互易的方式计算电磁场灵敏度,只需计算两个基本相同的边值问题(原始场和伴随场),然后对两个相应的场进行点积积分,便可得到观测的电磁场分量对电导率参数的偏导数矩阵.采用一维各向同性模型对算法进行了检验,并通过与一维各向同性算法比较,验证了本文灵敏度计算方法的准确性.然后对一维各向异性模型和二维各向异性模型进行了计算分析,分析了不同电磁场分量在高低阻各向异性介质中的灵敏度分布特征.The calculation of sensitivity is a key link in the linear inversion of marine controlled source electromagnetic data,which determines the quality and efficiency of electromagnetic data inversion,so it is necessary to examine and analyze the sensitivity calculation.In this paper,we derive the formula for calculating the sensitivity in the controlled-sources electromagnetic 2.5-dimensional inversion in the frequency domain,and use the adaptive unstructured finite element algorithm to calculate the electromagnetic response,and the adjoint reciprocal method to calculate the electromagnetic sensitivity,which only needs to calculate two basically the same bound-value problems(the primary field and the adjoint field),and then integrate the dot product of the two corresponding fields to get the deviation of the observed electromagnetic field components from the conductivity parameter.The algorithm is examined using a one-dimensional isotropic model,and the accuracy of the sensitivity calculation method in this paper is verified by comparing it with the one-dimensional isotropic modeling algorithm.Then the one-dimensional anisotropic model and the two-dimensional anisotropic models are computationally analyzed to characterize the sensitivity distributions of different electromagnetic field components in high-and low-resistance anisotropic media.

关 键 词：灵敏度 反演 电磁场 各向异性介质 

分 类 号：P631[天文地球—地质矿产勘探] P738[天文地球—地质学]