A Space-Time Self-Adaptive Gaussian Beam Migration with Optimized Dynamic Beam Parameter

In Gaussian beam (GB) method, initial beam parameters are the principal factors influencing the accuracy of seismic depth imaging. To overcome the shortcoming of conventional space-time Gaussian beam migration, a new space-time self-adaptive Gaussian beam migration approach is proposed by introducing the optimized dynamic beam parameter to the construction of beam. The beam width of our method at each time step of central space-time ray can be automatically calculated to obtain a more stable beam propagation, which is equal to the wavelength limited by local velocity field. Based on the refactored source wavelet and Kirchhoff integral equation, the direct and backward wave-fields are constructed in 2D acoustic media expressed by space-time self-adaptive Gaussian beam for the implementation of migration. The proposed method resolves the imaging contradictions between the shallow and deep regions caused by constant beam parameter. Numerical experiments conducted demonstrate the accuracy of this new optimal approach.