In petroleum seismic exploration,dense seismic ray coverage is often guaranteed through dense seismic sources and geophones.Dense ray coverage facilitates the high-resolution 3D velocity structure imaging of near surf...In petroleum seismic exploration,dense seismic ray coverage is often guaranteed through dense seismic sources and geophones.Dense ray coverage facilitates the high-resolution 3D velocity structure imaging of near surfaces using surface waves.In this study,the 3D velocity and anisotropy structure of a petroleum exploration area are obtained using the azimuth-dependent dispersion curve inversion(ADDCI)method.Imaging results show that low-velocity zones correspond to a river channel.The fast propagation direction(FPD)of S-waves along this channel is basically consistent with the direction of the channel.The eastern part of the study area has a surface sediment layer with a thickness of less than 20 m,which corresponds to the sand and gravel deposits formed by the river alluvial deposition near the surface.In addition,a relatively thick sedimentary layer is formed on the southern side of the study area.The anisotropy shows that the FPD is positively correlated with the direction of alluvial fl ow and that the magnitude of anisotropy in the deep part is greater than that in the shallow part.Inversion results are basically consistent with the geological data and suggest that the obtained model can truly refl ect the 3D velocity structure and anisotropy of the near-surface area.This study shows that the ADDCI method can maximize the high-energy surface waves in exploration data to obtain near-surface velocity structures,which provide a highly accurate model for near-surface static correction.展开更多
基金supported by the National Key Research and Development Program of China(No.2017YFC0601206)the Science and Technology Innovation(Seedling Project)Cultivation Program of Sichuan Province in 2020(No.2020127)the National Natural Science Foundation of China(Nos.41674059,41340009)。
文摘In petroleum seismic exploration,dense seismic ray coverage is often guaranteed through dense seismic sources and geophones.Dense ray coverage facilitates the high-resolution 3D velocity structure imaging of near surfaces using surface waves.In this study,the 3D velocity and anisotropy structure of a petroleum exploration area are obtained using the azimuth-dependent dispersion curve inversion(ADDCI)method.Imaging results show that low-velocity zones correspond to a river channel.The fast propagation direction(FPD)of S-waves along this channel is basically consistent with the direction of the channel.The eastern part of the study area has a surface sediment layer with a thickness of less than 20 m,which corresponds to the sand and gravel deposits formed by the river alluvial deposition near the surface.In addition,a relatively thick sedimentary layer is formed on the southern side of the study area.The anisotropy shows that the FPD is positively correlated with the direction of alluvial fl ow and that the magnitude of anisotropy in the deep part is greater than that in the shallow part.Inversion results are basically consistent with the geological data and suggest that the obtained model can truly refl ect the 3D velocity structure and anisotropy of the near-surface area.This study shows that the ADDCI method can maximize the high-energy surface waves in exploration data to obtain near-surface velocity structures,which provide a highly accurate model for near-surface static correction.
