Three-component Joint Inversion of Large Loop Transient Electromagnetic Field

摘要

The TEM response of large loop source on the surface of horizontally layered media can be equivalent to the joint-response of several electric dipoles when the loop is divided into a lot of short lines from which we can get electromagnetic three-component integral expression of large loop source on the surface of layered media.Since the analytical expression of the response is unavailable,digital filtering can be used to do TEM three-component 1-D forward modeling calculation.Based on the idea of inverse function,the definition of apparent resistivity can be available by a calculating method of the first derivative-based approximation.On the basis of all-region apparent resistivity and apparent depth,the basic model for multi-component inversion can be established and damped least squares method is used for multi-component joint inversion of large loop transient electromagnetic.At last,H-type model calculation has been made to validate the effectiveness of joint inversion of three-component.