Study and application of PS-wave pre-stack migration in HTI media and an anisotropic correction method

摘要

Anisotropy correction is necessary during the processing of converted PS-wave seismic data to achieve accurate structural imaging,reservoir prediction,and fracture detection.To effectively eliminate the adverse effects of S-wave splitting and to improve PS-wave imaging quality,we tested methods for pre-stack migration imaging and anisotropic correction of PS-wave data.We based this on the propagation rules of seismic waves in a horizontal transverse isotropy medium,which is a fractured medium model that reflects likely subsurface conditions in the field.We used the radial (R) and transverse (T) components of PS-wave data to separate the fast and slow S-wave components,after which their propagation moveout was effectively extracted.Meanwhile,corrections for the energies and propagation moveouts of the R and T components were implemented using mathematical rotation.The PS-wave imaging quality was distinctly improved,and we demonstrated the reliability of our methods through numerical simulations.Applying our methods to three-dimensional and three-component seismic field data from the Xinchang-Hexingchang region of the Western Sichuan Depression in China,we obtained high-quality seismic imaging with continuous reflection wave groups,distinct structural features,and specific stratigraphic contact relationships.This study provides an effective and reliable approach for data processing that will improve the exploration of complex,hidden lithologic gas reservoirs.