1887

Abstract

A method to localize conductive layers in a horizontally stratified media is presented in this paper. A loop-loop<br>system is assumed to stay on the earth surface, here modeled as a conductive half-space hosting a more<br>conductive layer as inhomogeneity. The transmitter is a vertical magnetic dipole and the receiver can measure<br>both vertical and horizontal magnetic field components (Hz and Hr, respectively) in the frequency domain.<br>The influence of the inhomogeneity on the magnetic field has been calculated through a detectability function Δ.<br>Using the parameters related to the extremals of Δ and their analysis of stability under variations of size and<br>conductivity contrast, it was possible to find the position of the inhomogeneity’s center corresponding to the<br>maximum influence in the measurements. Such a position is defined as main zone center. Best results were<br>obtained through Hr amplitude.<br>The main zone center was found to be po = 0.16 r, where r is the transmitter-receiver separation. Using this<br>result, it was drawn a plot of maximum values of Δ, calculated through Hr amplitude, versus po. Such plot<br>indicates the conductivity distribution in a 1D earth, and the extremals of the curve correspond to the center of<br>the more conductive layers. The maximum error in this method is about 30 %. The curves so drawn can be very<br>helpful to electromagnetic data interpretation because they are very similar to the well-known apparent<br>resistivity curves, largely used for electric and magnetotelluric interpretation methods.

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/content/papers/10.3997/2214-4609-pdb.215.sbgf216
1999-08-15
2021-10-24
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http://instance.metastore.ingenta.com/content/papers/10.3997/2214-4609-pdb.215.sbgf216
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