Seismic wave field decomposition method based on vector rotation in τ-p domain
(2.School of Geophysics and Information Technology, China University of Geosciences (Beijing), Beijing, China 100083)
【Abstract】High-fidelity elastic wave field decomposition has become a key processing step in multi-wave and multi-component seismic exploration. Conventional wave filed decomposition methods can be classified into two categories: kinematic methods and dynamic methods. Kinematic methods decompose the wave filed into P-P wave field and P-SV wave field in τ-p domain or in spatial domain. Dynamic methods focus on obtaining polarization characteristics of different types of wave. However, neither of them can achieve ideal decomposition results because of their inherent limitations. Motivated by the idea of combining both kinematic and dynamic characteristics of the wave field, a wave field decomposition method based on vector rotation in τ-p domain was proposed in this paper. It takes near-surface velocity as the key parameter of wave field decomposition and applies polarity rotation to the vertical and horizontal components of seismic wave field in τ-p domain. According to the polarization characteristics of different types of wave, it decomposes seismic wave field into P-P wave field and P-SV wave field to the corresponding polarization directions respectively. Model tests are carried out based on layered medium model and Marmousi-II model, and the method is also applied to real seismic data. The results demonstrate that the method can separate P-P wave and PSV wave more accurately compared with conventional methods. It avoids energy anomaly, wave field aliasing and spatial aliasing and preserved amplitude well after wave field decomposition.
【Keywords】 multi-component; wave field decomposition; τ-p transform; vector rotation;
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