Elastic wave-mode separation for anisotropic media based on equation-decoupling method

Due to the coupling characteristics of P-wave and S wave in anisotropic media, the acquisition of P wave information is of great significance for seismic data acquisition and processing of anisotropic unconventional reservoirs. Conventional methods are mainly divided into two categories: Helmholtz decomposition based on divergence curl field and acoustic approximation based on dispersion relation. However, both of these methods change the amplitude and phase information of P wave field, and further affect the final results of forward numerical simulation and P wave migration imaging. Based on the equation decoupling method, the coupling terms of P wave and S wave in the component of elastic stiffness coefficient are approximated to linear functions of P - and S wave modulus, and the separate P wave and S wave equations are derived, so as to realize the separation of P wave and S wave fields in anisotropic media. Compared with the conventional method, the amplitude and phase information of P -wave field obtained by the " equation decoupling" algorithm is more accurate, and the wave field information is more complete, which can provide an important guarantee for P-wave data processing in anisotropic media.