AN INTEGRAL EQUATION REPRESENTATION OF WIDE-BAND ELECTROMAGNETIC SCATTERING BY THIN SHEETS

Abstract

An efficient, accurate numerical modeling scheme has been developed, based on the integral equation solution to compute electromagnetic (EM) responses of thin sheets over a wide frequency band. The thin‐sheet approach is useful for simulating the EM response of a fracture system in the earth. The focus of this development has been the accuracy of the numerical solution over a wide‐band frequency range of up to 100 MHz. The effect of displacement currents is included to correctly evaluate high‐frequency EM scattering. Currently, EM responses of two thin sheets with different geometrical and electrical properties embedded in a three‐layer earth can be modeled over a frequency band of 10 ⁻³ to 10 ⁸ Hz. The layered earth and the sheets can be electrically dispersive, an important feature that allows analysis of frequency‐dependent characteristics of the model under investigation. The source field can be generated by a remote or local electric or magnetic dipole located on the surface or in a borehole. A plane‐wave source can also be used, and numerical analyses have been made for magnetotellurics and the high‐frequency impedance method.