3D pre‐stack Kirchhoff time migration of PS‐waves and migration velocity model building

Dai, Hengchang; Li, Xiang‐Yang; Conway, Paul

doi:10.1190/1.1845099

Cited by 4 publications

(2 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For 3D, this is not an easy task, particularly if the 3D velocity model varies with azimuth. In this data set, we find that the azimuthal velocity variation is weak, satisfying the condition of transverse isotropy (Dai, Li and Conway 2004). Therefore, the tools developed for the 2D case can be applied directly to this 3D data set.…”

Section: Model Updatingmentioning

confidence: 84%

Converted‐wave imaging in anisotropic media: theory and case studies

Dai

Mancini

2007

Geophysical Prospecting

Self Cite

View full text Add to dashboard Cite

SUMMARYCommon-conversion-point binning associated with converted-wave (C-wave) processing complicates the task of parameter estimation, especially in anisotropic media. To overcome this problem, we derive new expressions for converted-wave prestack time migration (PSTM) in anisotropic media and illustrate their applications using both 2D and 3D data examples.The converted-wave kinematic response in inhomogeneous media with vertical transverse isotropy (VTI) is separated into two parts: the response in horizontally layered VTI media and the response from a point scatter. The former controls the stacking process and the latter controls the process of PSTM. The C-wave traveltime in horizontally layered VTI media is determined by four parameters: the C-wave stacking velocity V C2 , the vertical and effective velocity ratios γ 0 and γ eff , and the C-wave anisotropic parameter χ eff . These four parameters are referred to as the C-wave stacking velocity model. In contrast, the C-wave diffraction time from a point scatter is determined by five parameters: γ 0 , V P2 , V S2 , η eff and ζ eff , where η eff and ζ eff are, respectively, the P-and S-wave anisotropic parameters, and V P2 and V S2 are the corresponding stacking velocities. V P2 , V S2 , η eff and ζ eff are referred to as the C-wave PSTM velocity model. There is a one-to-one analytical link between the stacking velocity model and the PSTM velocity model. There is also a simple analytic link between the C-wave stacking velocities V C2 and the migration velocity V Cmig , which is in turn linked to V P2 and V S2 .Based on the above, we have developed an interactive processing scheme to build the stacking and PSTM velocity model and to perform 2D and 3D C-wave anisotropic PSTM.Real data applications show that the PSTM scheme substantially improves the quality of Cwave imaging compared with the DMO (dip moveout) scheme, and these improvements have been confirmed by drilling.

show abstract

Section: Model Updatingmentioning

confidence: 84%

Converted‐wave imaging in anisotropic media: theory and case studies

Dai

Mancini

2007

Geophysical Prospecting

Self Cite

View full text Add to dashboard Cite

show abstract

“…The second example is a 3D 4C data from North Sea (Courtesy KerMcGee). Further details of this data can be found in Dai et al (2004). Again, the purpose is to improve imaging beneath gas clouds.…”

Section: Data Examplesmentioning

confidence: 99%

Converted‐wave imaging in anisotropic media: An overview

Dai

Mancini

2004

SEG Technical Program Expanded Abstracts 2004

Self Cite

View full text Add to dashboard Cite

This paper reviews the recent developments in convertedwave (C-wave) processing for vertical transverse isotropy (VTI), and addresses issues such as how many parameters are required to perform C-wave anisotropic prestack time migration (PSTM), and how to estimate these parameters. Both recent 2D and 3D data examples will be used to illustrate these developments. The converted-wave kinematic response in inhomogeneous VTI media is separated into two parts: the zero-dip response for horizontally layered VTI media and the all dip response from a point scatter. The former controls the stacking process and the latter controls the process of PSTM. The C-wave traveltime in horizontally layered VTI media is determined by four parameters: the C-wave stacking velocity V C2 , the vertical and effective velocity ratios γ 0 and γ eff , and the C-wave anisotropic parameter χ eff. These four parameters are referred to as the C-wave stacking velocity model. In contrast, the C-wave diffraction time from a point scatter is determined by five parameters: γ 0 , V P2 , V S2 , η eff and ζ eff , where η eff and ζ eff are, respectively, the P-and S-wave anisotropic parameters, and V P2 and V S2 are the corresponding stacking velocities. V P2 , V S2 , η eff and ζ eff are referred to as the C-wave PSTM velocity model. There is a one-to-one analytical link between the stacking velocity model and the PSTM velocity model. Based on the above understanding, we have developed an interactive processing scheme to build the stacking and PSTM velocity model and to perform 2D and 3D C-wave anisotropic PSTM. Real data applications show that the PSTM scheme substantially improves the quality of Cwave imaging compared with the DMO scheme, and these improvements have been confirmed by drilling.

show abstract