Abstract
Accurate estimation of seismic quality factor (Q) is important in seismic data processing to correct for the velocity dispersion effects and to compensate for absorption losses through inverse Q filtering. To estimate it, often logarithmic spectral ratios of the non-stationary seismic signal between two depth levels are linearly inverted. As these ratios are usually derived from the standard Fourier transform (FT) which has a poor time-frequency resolution, this can lead to biased Q estimation. We have calculated spectral ratios from the high-resolution time-frequency spectrum using the Stockwell transform (ST). We then non-linearly inverted these improved spectral ratios to estimate Q using the Levenberg-Marquardt (LM) method. For a synthetic wedge model, results demonstrate a reasonable improvement in the accuracy of Q estimation with the combined ST-LM approach. Application on a real P-wave reflection seismic dataset revealed an anomalous attenuation zone of very low Q (29–75) values. Inverse Q filtering using the estimated Q profile has enhanced the seismic resolution below it and minimized the differential viscous losses. Frequency slice filtering on Q compensated data has improved the S/N ratio and hence the amplitude fidelity of reflectors.
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