| Earth media is characterized by its anisotropy.Seismic anisotropy is mainly manifested in the following aspects: seismic wave propagation velocity differs with the change of the propagation direction,body-wave couples mutually and S-wave splits,etc.As one of the leading-edge topics in seismology study,seismic anisotropy study is of theoretical and practical significance for the cognition of earth structure,the exploration and development of complex oil and gas reservoirs,and the forecasting of geological hazards as well.Through the analysis of structure characteristics and lithology of the shale gas project in south China,combined with the parameters in observation system of acquisition about reflection seismic,we designed the 2-D observation system for the anisotropic problems in shale gas project,meanwhile,we researched the seismic data on shales gas obtained by this system in NC area.By contrasting the processing procedure on conventional seismic data and shale gas seismic data in complex mountain area,we points out the differences on static correction in complex mountain shales gas seismic data.We find the problem of static correction that cased by using layer chromatography static correction on solving complex surface seismic data.we focus on the difficulty in velocity analysis on NMO stack and prestack time migration.We discuss the anisotropic factor on velocity analysis in complex mountains areas.We use the conventional velocity analysis methods and velocity picked up based on the assumption of VTI media on stack and prestack time migration respectively.Through comparing the different results of real data,we obtain the NMO method and prestack time migration method based on VTI media for NC project.By analyzing the section processed by regular processing and the processing considering anisotropic factor,we find the necessary of introducing anisotropic factor in seismic data processing about the shale gas and give the suitable processing procedure. |
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