Stable Q-compensated reverse-time migration based on regularization strategy

Viscosity is general in subsurface media, and the seismic waves are inevitably accompanied by amplitude attenuation and velocity dispersion during its propagation, which seriously reduces the accuracy and the resolution of seismic imaging. It is essential to consider attenuation-compensated strategy during seismic imaging, and the attenuation-compensated Reverse-Time Migration (RTM) based on the viscoacoustic wave equation can recover the amplitude attenuation and the phase distortion experienced by seismic waves along the propagation path. However, the attenuation of seismic waves varies exponentially, and the non-synchronous growth of the high and low frequency components during the compensation would face the challenge of numerical instability. For this reason, we propose in this paper a stable attenuation-compensated RTM based on a regularization scheme, which uses the decoupled constant Q fractional-order Laplacian viscoacoustic wave equation to describe the propagation effect of seismic waves in the subsurface media, and introduces an amplitude regularization term into the analytical solution in the time-wavenumber domain of this wave equation to ensure stable extrapolation of seismic wavefield during attenuation-compensated RTM. Migrated images of two- and three-dimensional synthetics and field data have demonstrated the feasibility and effectiveness of the proposed method. It can effectively solve the instability problem during attenuation-compensation and significantly improve the imaging quality of seismic data.