石油地球物理勘探2019，Vol.54Issue(2)：330-340,前插3,12.DOI:10.13810/j.cnki.issn.1000-7210.2019.02.011
VTI介质角度域叠前深度偏移
Angle-domain prestack depth migration in VTI media
摘要
Abstract
The angle domain migration in VTI media is discussed in this paper.Based on the angle domain migration of isotropic double-square-root equation,a wavefield extension operator of angle domain migration in VTI media is derived from the qP wave dispersion equation. The complex velocity and anisotropic parameter field are divided into two parts,one is lateral uniform background field,and the other is the disturbances of velocity and anisotropic parameters.Then the wave propagated at a uniform velocity and anisotropy field is processed in the frequency wavenumber domain,and the wave propagated at a velocity and anisotropy disturbance field is corrected by time-shift in the spatial domain.So the accuracy of wave field extension is greatly improved.Based on our model and real data tests,the following observation are obtained:A.Because the isotropic migration method does not take into account the influence of anisotropy parameters, the diffraction wave cannot be completely converged and the wavefield is misfocused,which causes low resolution and low signal-to-noise ratio.So conventional migration methods cannot accurately image geological structures,while the VTI media migration can accurately image faults,salt mounds,and small scale geological bodies;B.For the angle domain common imaging gathers(ADCIGs)generated by the prestack migration, the event of the isotropic method cannot be equalized, the residual fault diffraction is wound and the wavefield cannot be properly focused,which cannot correctly reflect local geological characteristics,while the ADCIGs from VTI media migration are relatively straight,the angle range is wider,the wavefield is accurately positioned.So the image accuracy is higher. Therefore,the angle domain migration in VTI media can be suitable for complex-structure accurate imaging.关键词
VTI介质/角度域偏移/双平方根方程/频散关系/波场延拓Key words
VTI media/angle domain migration/double square-root equation/dispersion equation/wavefield continuation分类
天文与地球科学引用本文复制引用
李江,李庆春..VTI介质角度域叠前深度偏移[J].石油地球物理勘探,2019,54(2):330-340,前插3,12.基金项目
本项研究得到国家自然科学基金项目"海底节点地震波场模拟与转换波成像方法研究"(41874123)资助. （41874123）
