Method of correcting formation resistivity well logs for the effects of formation layer inclination with respect to the wellbore

摘要

A method for correcting response of an induction logging instrument for inclination of earth formations with respect to an axis of the instrument. The instrument has a transmitter and a plurality of receivers at spaced apart locations. The method includes calculating expected receiver responses of simulated media having different conductivities. The calculations are performed for a plurality of different inclinations. The calculations are also performed for media having a plurality of different conductivity contrasts. 2-dimensional filters corresponding to a charge effect portion of each of the expected responses are calculated. 2-dimensional filters corresponding to a volumetric effect portion of each of the expected responses are calculated. An angle of inclination of the earth formations with respect to the instrument is determined. An approximate conductivity contrast of the earth formations is determined. Coefficients are interpolated between the 2-dimensional charge effect filters having simulated inclinations and contrasts closest to the angle of inclination and conductivity contrast of the formations. The interpolated filter coefficients are applied to measured receiver responses, generating charge effect-filtered measured responses. Coefficients are interpolated between the 2-dimensional volumetric effect filters having simulated inclinations and conductivity contrasts closest to the angle of inclination and conductivity contrast of the formations. The interpolated coefficients are applied to the charge effect-filtered measured responses to calculate corrected receiver responses.