S1 and S2 separation based on SS-wave splitting analysis

Abstract

Shear wave splitting analysis is a key technology for pure shear wave (SS) data processing of azimuthally anisotropic media. In this paper, the Alford rotation method (Alford, 1986) is applied to the 4C field data for the shear wave splitting analysis. During the calculation of fracture parameters from a shallow window, the fracture orientations were limited to a certain angle range according to the shear wave splitting characteristics on the azimuthal stack sections of the 4C data of the radial and transverse direction. Then according to the fracture orientations obtained from each CMP, the 4C data was rotated to obtain new 4C data, and fast shear wave (S1) and slow shear wave (S2) are separated, and better stack imaging results are achieved. The new 4C data after rotation was used to judge whether the fracture orientation changes with depth, and the judgment criteria is proposed in this paper and is verified by synthetic data and is applied in real data.