A stable Q reverse time migration method with regularization

Abstract

Q reverse time migration (Q-RTM) is an effective method to compensate the deep amplitude energy of seismic records and improve the resolution. However, an important problem of the Q-RTM method is that the wavefield extrapolation process will generate high-frequency noise, resulting in unstable imaging results. On the basis of the decoupled viscousacoustic wave equation based on standard linear solid model, a viscoacoustic wave equation with regularization term is derived, and a stable Q-RTM based on this equation is developed. And the detailed derivation process of the viscousacoustic wave equation containing the regularization term is given. Compared with the commonly used low-pass filtering method, the method based on the regularization term avoids the design of the filter and the selection of the cutoff frequency. We test the Q-RTM method on the BP gas layer model, the Marmousi model and real seismic data. The numerical example results show that the Q-RTM method proposed in this paper can effectively solve the instability problem, compensate the amplitude energy, and obtain a higher resolution seismic profile.