Steeply dipping structural target-oriented viscoacoustic least-squares reverse time migration and its application

Steeply dipping structural imaging is a significant challenge because surface geophones cannot obtain seismic primary reflection wave information from steeply dipping structures. Prismatic waves with a significant amount of steeply dipping information can be used to improve the imaging effect on steeply dipping structures. Subsurface attenuation leads to amplitude loss and phase distortion of seismic waves, and ignoring this attenuation during imaging can cause blurring of migration amplitudes. In this study, we proposed a steeply dipping structural target-oriented viscoacoustic least-squares reverse time migration (LSRTM) method with prismatic and primary waves as an objective function based on the viscous wave equation, while deriving Q-compensated wavefield propagation and joint operators of prismatic and primary waves and the Q-compensated demigration operator. Numerical examples on synthetic and field data verified the advantages of the proposed viscoacoustic LSRTM method of joint primary and prismatic waves over conventional viscoacoustic LSRTM and non-compensated LSRTM when using attenuating observed data.