Balance Full Waveform Inversion Update by Compensating the Q-effects with Dissipation-Dispersion Decoupling

Seismic attenuation distorts the seismic data by damping the amplitudes (dissipation) and shifting the phases (dispersion), especially in the presence of fluid or partial melt in the Earth interior. The conventional full waveform inversion (FWI) without considering the correction of seismic attenuation could lead to artifacts in inverted seismic models. Thus, it is essential to incorporate the seismic attenuation (Q) into the full FWI workflow to conduct the Q-FWI. However, in the Q-FWI applications with the reflection acquisition geometry, the high-attenuation structure would create a wiped-out zone in the FWI gradient due to the double-damping issue, which results in an imbalanced update and a slow convergence. In this study, we propose to construct a Q-free FWI gradient with Q-compensation. By using a recently developed viscoacoustic wave propagator with dissipation-dispersion decoupling, this compensation can be done conveniently by keeping the dispersion term and flipping the dissipation term when we simulate both the forward and the time-reversed adjoint wavefields. As a result, the FWI gradient obtained by interacting these two wavefields has correct kinematics and Q-free amplitudes. We find that this Q-compensated FWI can balance the update between Q- and no-Q-areas, which we demonstrate using synthetic examples.