Abstract

Geologically complex structures require reasonably clear seismic image for them to be identified with relatively higher degree of confidence and acceptable level of certainty. Complex structures carry with them some geologic problems that are not satisfactorily handled in routine seismic data processing designed for simple geologic conditions. Foremost of these problems are steep dips and rapid velocity variation which characterize seismic data acquired over complex geological and structural settings. They invariably degrade stacking. Applying special algorithms designed to handle these problems such as dip moveout and steep dip migration, while not perfect solutions, help tremendously in improving the seismic image of these complex structures. Subsequent interpretation of the stacked data through seismic modeling yields an optimal velocity field that is further applied to a recursive pre-stack depth migration process. The depth migrated data results in a more enhanced image of the subsurface.

We adopted this processing and interpretation strategy to the identification of a huge antiformal structure in the thrust fault system of Southwest Palawan. The much improved image of the structure indicates creditable result for the method and it demonstrates that prospective plays and viable drilling objectives can be identified with reduced risk in geologically complex environment such as Southwest Palawan.