Chapter 4: PS Azimuth Moveout

The 3-D portion for this dissertation begins with Chapter 4. As discussed previously, OBS acquisition has many advantages. But it also presents new challenges for seismic processing and imaging. An example of such a challenge is dealing with irregularity in the acquisition geometry.

This chapter presents the azimuth moveout for converted waves, PS-AMO, that is the sequential application of converted-wave dip moveout and its inverse. PS-AMO preserves the resolution of dipping events and internally applies a correction for the lateral shift between the common midpoint and the common reflection/conversion point. This chapter also presents the implementation of PS-AMO in the log-stretch frequency-wavenumber domain.

Chapter 4 also formulates the irregular acquisition geometry problems in the least-squares problem. This method collapses the crossline offset dimension to form a 4-dimensional cube to be used for migration using the common-azimuth downward-continuation operator future processing techniques, such as common-azimuth migration. This method uses the information of surrounding traces, through the PS-AMO operator, to fill in the acquisition gaps, and form a regularized 4-dimensional cube. The solutions for the least-squares problem are illustrated using the real 3-D OBS dataset from the Alba oil field in the North Sea.