Time domain electromagnetic migration imaging

Abstract

Abstract-This article is about the study of time domain electromagnetic data migration imaging. First, based on the electromagnetic diffusion theory and the boundary conditions, we deduce the analytical formula of electromagnetic migration field. Then, we complete the calculation of electromagnetic migration field filter by electromagnetic migration field theory in frequency domain. The analytical electromagnetic migration filter is discretized to achieve electromagnetic numerical migration filter to make it able to be applied into practical discrete sampling. By analyzing the error caused by of discretization procedure according to the theory of electromagnetic migration filter, we deduce discretization error correction formula. Moreover, we study and realize the transform from time domain to frequency domain, and make it able to be used in time domain electromagnetic migration imaging. In order to test migration imaging technology, whole space 2D or 3D geoelectric models are built with the transmiter-receiver distance varying from near field to several thousand kilometers. Using the technology presented by this paper to the numeric data, the reasonable position of underground exploration body can be recovered. Finally, we deduce 2D migration field analytical formula in time domain and discretize it, then complete the numeric calculation in time domain directly. We analyze the kernel function of time domain electromagnetic migration filter and its influence factors, and test the effect of time domain migration field imaging by several simple geoelectric models.