Conclusions

We have applied  post stack migration to obtain a preliminary seismic images of tapes 20 and 21. Tape 20 was the most challenging data set to process due to the presence of conflicting dips and backscattering from the surrounding structures. The strategy to  re-pick velocities to overcome under-migration and to flatten reflectors coming from the seismic line only was not very successful. The under-migration still persisted and artifacts due to the backscattering as well. The  DMO correction improved the migration of the high dipping reflectors but it also introduced several artifacts, suggesting that further treatment to improve the image was still needed. Finally we suggested to include DMO and migration on the pre-stacked data. Additional suggestions include a second pre-stack migration to further enhance the image. We interpreted the preliminary image delineating the top of  the igneous basement below a sedimentary layer. The sedimentary layer thins and the igneous rock breaks through the sedimentary layer forming the high dipping structures.

Contributors

Kathie Guerra: Read in data files into SEGD files, Tape 21 pre-processing, main processing (velocity analysis, NMO, migration) and interpretation
Edith Sotelo: Tape 20 pre-processing, NMO- migration, investigated Paradigm modules for pre-stack processing, proposed pre-stack processing workflow, interpretation
Jingxuan Wei: Tape 20 velocity picker expert : initial stacking  velocities, re-picked higher velocities to improve under- migration, re-picked stacking velocities to flatten only reflectors below the seismic line to improve backscattering issues.
Ji Hyun Yang: Tape 20 Pre-processing, investigated several Paradigm modules to implement DMO, Applied DMO processing to the data set.