The response functions of electromagnetic wave logs in the 2-D axis-symmetric formation
二维轴对称介质中电磁波测井的响应函数

The fundamental feature of electromagnetic wave logs is the logging response(phase difference and amplitude ratio)dependent on the dielectric constant and conductivity in general.In this paper we derived the response functions(RF)of the electromagnetic wave logs in a 2-D axis-symmetrical formation and proposed a fast algorithm based on the integral equation of electromagnetic field and the weak scattering approximation.Based on a relationship between the RF and Jacobi matrix,a novel method which is independent of the forward modeling for a fast algorithm of Jacobi matrix employing the RF was advanced.The theoretical results about the investigating characteristics of phase difference and amplitude ratio were also gained.It was shown that the phase difference is sensitive to the conductivity(dielectric constant)within substantially the same volume as the amplitude ratio is sensitive to the dielectric constant(conductivity)in homogeneous medium.