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Separating Quasi P Wave in VTI Medium by Composing Main Stress
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 77th EAGE Conference and Exhibition 2015, Jun 2015, Volume 2015, p.1 - 5
Abstract
The key technology of vector-wave imaging in anisotropic medium is to separate quasi P (qP) and S wavefield. So far, it is very difficult to quickly and accurately obtain real P and S wave by wave-field separation. In this paper, based on theory of dynamic elasticity, the concept of pressure field which build relationship between seismic P-wave and main stress field is introduced. It is known that, in homogeneous elastic isotropic media, P-wave decomposed by Helmholtz formula is a real strain field, and has the same kinematics and dynamics characteristics with pressure field. However, qP-wave is not equal to a pure pressure field in vertical transverse isotropic (VTI) media. A new method of qP-wave separation by composing main stress is proposed in this paper. Numerical examples demonstrated that the new method can be used in qP-wave mode separation in VTI media, and provide a new path for elastic anisotropic vector-wave fast imaging.