Open AccessThree‐dimensional time‐domain electromagnetic modelling using a compact finite‐element frequency‐stepping method
Author(s) -
Gupta P. K.,
Raiche A. P.,
Sugeng F.
Publication year - 1989
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1989.tb06007.x
Subject(s) - helmholtz equation , finite element method , overburden , mathematical analysis , electromagnetic wave equation , partial differential equation , time domain , integral equation , perfectly matched layer , electrical conductor , frequency domain , mathematics , geometry , computer science , electromagnetic field , geology , physics , boundary value problem , engineering , geotechnical engineering , structural engineering , quantum mechanics , optical field , computer vision
SUMMARY A class of time‐domain electromagnetic modelling problems is solved using a frequencystepping solution to the vector diffusion equation. The model consists of a heterogeneous structure embedded in the bottom layer of a two‐layer half‐space. The compact finite‐element method (CFEM) is used for the vector Helmholtz equation part of the solution. The CFEM combines finite‐element and integral‐equation techniques in a direct, rather than an iterative, solution. The partial use of an isoparametric formulation allows the modelling of a dipping heterogeneous zone without a staircase effect. For sheet‐like models, the technique is consistent with modelling results for resistivity contrasts of up to 300: 1. As an illustrative application, the responses of vertical and dipping prisms, in contact with and below a conductive overburden, are compared.