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Seismic interpretation, PSDM, seismic inversion, NMO, AVO, acquisition design, the wavelet, synthetics, polarity and all other topics about Geophysics and Seismic Interpretation.
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Migration in complex geological areas

Fri Feb 22, 2013 2:00 pm

Hello, I am new to processing and interpretation of seismic data. So I was wondering what is the best migration method to be applied during the processing when we are looking for subsalt reflections? I know prestack depth migration algorithms are a must when subsalt imaging is required, but which PSDM method gave you best results in practice? Also I would like to know if there is a PSTM algorithm except Kirchoff migration that can be used to get better subsalt image quality.

NOTE: I am working on a 2D survey if that is relevant.

Re: Migration in complex geological areas

Thu Oct 03, 2013 3:36 pm

Buenas soy procesador sismico con un poco de experiencia y te puedo decir que en produccion la que mas se usa es la PSTM (Kichooff) si el dato esta en 2D, lo que si te recomiendo que tienes que acondiccionar el dato previamente antes de hacer la migracion en cuanto a la conservacion de amplitudes sismicas y usar por ejemplo una secuencia como si fueras a hacer AVO.

Re: Migration in complex geological areas

Thu Feb 13, 2014 1:09 pm

Sorry got up late.
But still replying as it may benefit you next time.
If the structure is complex like salt ..., best is PSDM.
best module available are Reverse time/ shot / Beam or CRAM / Kirchhoff. Arranged according to decreasing cost and decreasing quality.
Usually Kirchhoff is good enough.
happy time ahead in the wonderland of Seismic
Rajesh

Re: Migration in complex geological areas

Sat Feb 15, 2014 7:43 am

While Rajesh is totally correct, I think its worth commenting that there are some hybrid pre-stack time/depth migrations that might give a "good enough" solution depending on what you are after.

These are usually Kirchhoff pre-stack time migrations that use more sophisticated approaches to developing an operator which is asymmetric and varies with the (RMS) velocity of the output location - its a better approximation than a standard Kirchhoff preSTM but one that runs many times faster than a standard preSDM.

In general, things like preSDM obey the "80/20" rule - in that 80% of the time/cost is in getting the last 20% of image improvement. Hybrid PreSTM/DM routines can get you to the "80%" solution for 20% of the time/cost.

Re: Migration in complex geological areas

Sat Feb 15, 2014 1:06 pm

Yes well said. The 80-20 rule amply defines the situation.
In short any algorithm that accounts for ray bending/ multi path will do.
Thanks
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