Conclusions

We presented a series of important concepts in non-conventional PS-seismic processing for an important problem in converted wave seismic processing: the polarity flip.

We used frequency domain common shot migration in order to obtain an image of the subsurface with converted wave data. The shot-profile migration algorithm enables the use of two different velocity models, one for the P-wave path and the other for the S-wave path of the data; therefore, we do not have to introduce a mixed PS-velocity model.

We introduce common angle gather for converted waves. In this domain the normal incidence reflection is determined by the polarity flip angle, this polarity flip angle helps to regularize the polarities in the angle domain; we demonstrated this fact with a synthetic PS data set.

The introduction of common angle gather in converted waves seismic processing and imaging brings a series of opportunities for building S-velocity models, and analysis of amplitude versus angle for converted waves; therefore, the opportunity to extract as much information as possible from PS seismic data.

 

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Figure 6 Final migration sections: The top figure shows the image with the polarity correction in the model space. The center figure shows the image with the polarity correction in the data space. The bottom figure shows the image without any correction