Stable and High-Efficiency Attenuation Compensation in Reverse-Time Migration Using Wavefield Decomposition Algorithm

摘要

Q-compensated reverse time migration (Q-RTM) can compensate seismic attenuation caused by the anelastic behavior of subsurface media. Although, the traditional Q-RTM has high computational efficiency, it is instable because the high frequency or wavenumber ambient noise is exponentially boosted during forward and backward seismic wavefield propagation. The existing stable Q-RTM method costs twice as much computing time and memory compared to the traditional Q-RTM. In this letter, we propose a new Q-RTM method to address the above issues simultaneously. First, a new viscoacoustic wave equation is derived based on a wavefield decomposition method to obtain the velocity-dispersion-only and viscoacoustic wavefields efficiently. Then, a theoretical framework of stable and high-efficiency Q-RTM method is proposed based on the velocity-dispersion-only and viscoacoustic wavefields. The synthetic example shows that the new stable Q-RTM results match well with the reference images (without attenuation images). Moreover, the field data images also demonstrate the stability and high-efficiency of our proposed Q-RTM method.