Q-PHASE COMPENSATION OF SEISMIC RECORDS IN THE FREQUENCY-DOMAIN

The attenuation process acts as a low-pass filter that attenuates the high frequencies (absorption) of the signal spectrum and also changes the phase of the seismic wavelet (dispersion). Seismic frequency losse s are usually recovered according to an appropriate processing techniq ue (such as deterministic or statistical deconvolution methods), while phase distortions are generally disregarded. Therefore, accurate proc essing of seismic data requires a careful investigation of the relatio nship between absorption and phase. In this article, a procedure is pr esented to accomplish this goal. To account for anelastic losses, a co mplex power function of frequency for the phase velocity is introduced into the one-way wave-field equation in 1D. The compensation, for bot h effects (absorption and dispersion) described here, is analyzed in t he context of wave-field extrapolation in one dimension 1D, equivalent to that in the f-k domain as phase-shift and/or Stolt migration. The phase-only inverse Q filtering works in the frequency domain. It provi des for dispersion according to a constant-Q (frequency-independent) m odel and is valid for any positive value of Q. The extension of this a lgorithm for a Q depth-variable model is also shown. The amplitude com pensation is accomplished through the use of a standard statistical ap proach. Synthetic and real data are shown to illustrate both amplitude and phase inverse Q filtering of seismic reflection records.