Abstract: A method and system for processing induction measurements of sub-surface formations taken by an induction logging system at various depths in a borehole is disclosed. The method reduces the unwanted contributions in the measurements from induction currents flowing in the formations spaced apart from each measurement depth (shoulder effect) and the effects of variations in the logging system transfer function with variations in the conductivity of the formations being investigated (skin effect). Shoulder effect is reduced by generating a spatial deconvolution filter which when convolved with the sonde response function sharpens the main lobe and reduces the sidelobes to near zero. The skin effect is reduced by filtering the quadrature-phase component measurements according to a non-linear spatial filtering function to obtain a correction component measurement representative of the change in the sonde response function as a function of the formation conductivity.

Abstract: A method and system for processing induction measurements of sub-surface formations taken by an induction logging system at various depths in a borehole is disclosed. The method reduces the unwanted contributions in each measurement from induction currents flowing in the formations spaced apart from each measurement depth. The spatial domain sonde response function obtained at zero conductivity is Fourier transformed and truncated at a spatial frequency less than the spatial frequency at which the transformed function first goes to zero. A Kaiser window transfer function is then selected and the inverse Fourier transform of the ratio of the Kaiser window function to the transformed truncated sonde response function is formed to obtain a deconvolution filter function which when convolved with the sonde response function reduces the non-zero sidelobes in the system response function and thus reduces the shoulder effect.