Analysis of sensitivity calculations in the inversion of marine controlled source electromagnetic fields in two-dimensional anisotropic media
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.
SensitivityInversionElectromagnetic fieldAnisotropic media
万方数据
维普
