S1P/S2P wave separation and shear wave splitting correction for SVP data

For shear（S）-wave source seismic exploration，extracting fracture information from the data and per- forming fast/slow S-wave separation and S-wave splitting correction are of great significance for S-wave seismic data imaging with azimuthal anisotropy. The difference between SP converted wave（P-wave converted from S-wave）in S-wave source exploration data and PS converted wave（S-wave converted from P-wave）is that the S-wave splitting occurs in the process of downgoing wave or upgoing wave propagation. Therefore，the S-wave split- ting characteristics of the SP wave are similar to those of the PS wave. In this paper，the tangent energy minimiza- tion method of PS wave is applied to the S-wave splitting analysis of SP wave to find the direction of underground cracks. In the application of 3D nine-component（3D9C）actual data，a technical process is formed based on the pre- processing of SP wave seismic data including common conversion point（CCP）gather extraction and NMO correc- tion，and the corresponding crack direction of CCP is obtained by azimuthal superposition. In addition，the fast and slow converted（S1P and S2P）wave separation is carried out. At the same time，a strategy is proposed to obtain the time difference by picking up the horizon on the fast and slow wave superimposed profile. After the time dif- ference is applied to the S-wave splitting correction，SVP without the S-wave splitting effect is obtained，and the image quality of the profile is improved. The application results of synthetic data and actual data show that the imaging profiles of S1P and S2P waves are significantly improved compared with those before separation，and the SVP reflection energy is improved after S-wave splitting correction，which verifies the feasibility of the proposed method for fast and slow wave separation and S-wave splitting correction in actual SP wave seismic data. © 2023 Editorial office of Oil Geophysical Prospecting. All rights reserved.