Viscoacoustic Full-Wavefield Migration and Its Application

Conventional acoustic full-wavefield migration (AFWM) based on one-way wave propagators is typically derived under the assumption of an acoustic medium. However, real subsurface media exhibit viscoacoustic properties, where seismic wave propagation is accompanied by amplitude attenuation and phase dispersion. As a result, AFWM and wavefield simulation approaches fail to accurately capture the viscoacoustic effects of realistic subsurface media. To address this issue, this paper derives a one-way wave propagator for viscoacoustic media based on the time-fractional viscoacoustic wave equation, and incorporates it into the framework of full-wavefield migration (FWM). A novel full-wavefield imaging method, referred to as viscoacoustic full-wavefield migration (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i>FWM), is proposed. The proposed <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i>FWM method is tested and compared with AFWM methods. Numerical experiments on a simple three-layer horizontal model, a gas chimney model with a highly attenuative gas layer, and the Marmousi model demonstrate that <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i>FWM significantly outperforms AFWM in imaging quality and multiple wave suppression when applied to viscoacoustic data. Furthermore, real data tests validate the superiority of the proposed method over AFWM in terms of imaging quality. The proposed method highlights the critical importance of accounting for viscoacoustic effects in seismic imaging and offers a robust solution for improving the accuracy of FWM in complex subsurface media.