Time versus frequency domain measurements: layered model

Abstract

The effect of receiver coil alignment errors δ on the response of electromagnetic measurements in a layered earth model is studied. The statistics of generalized least square inverse was employed to analyzed the errors on three different geophysical applications. The following results were obtained: (i) The FEM ellipiticity is insensitive to orientation error;(ii) The TEM has an error less than 1% for times greater than 0.5 msecs after turn off time. (iii) The standard errors of TEM and FEM for the important parameters of buried conductor models yield approximately the same errors for TEM and FEM data sets; for models with a conductive overburden, the FEM ellipticity gave substantially better parameter errors in comparison with TEM data; and all the data needed less time than the FEM in their high frequency content while among TEM data sets with low frequency content, the averaging times for the FEM ellipticity were shorter than the TEM quality.

Keywords: ellipticity, frequency domain, frequency electromagnetic method, model parameter, orientation error, time domain, transient electromagnetic method

Global Journal of Geological Sciences Vol. 3(2) 2005: 117-132