Improvement of Seismic Depth Imaging on Carbonate Reef Through the Application of Common Reflection Angle Migration: An Example From Salawati Basin, Indonesia

Abstract

We perform Pre Stack Depth Migration (PSDM) using Common Reflection Angle Migration on 2D onshore seismic lines from Salawati basin. This process was carried out in order to investigate the existence of reefal build which featured in time domain seismic section. In addition, the processing was expected to eliminate the pull-up effect on intra-carbonate layer due to high velocity influence. Pre-stack depth migration improves seismic limitation on imaging the geological condition where strong lateral velocity contrasts exist. The Miocene Carbonate Kais Formation of Salawati Basin is good example for applying this depth imaging, since the appearance of mounded structures in seismic cause some uncertainties of its geometry and existence. In addition to the common Kirchoff Migration in the standard Pre-stack depth migration, we also applied the Common Reflection Angle Migration in migration stage. It is multi arrival migration which works based on ray tracing, using all parts of the wave in a controlled aperture. Unlike conventional ray tracing method, in this case the ray tracing were performed from imaging point across all directions, including turning arrays to come out to the surface. Common Reflection Angle Migration which applied in PSDM process has proven to be efficient way to give clearer image of the carbonate layer of Miocene Kais Formation, consider acquire new seismic survey would cost many. It also has eliminated one of the mound structures which pre-defined as reefal build up in time domain seismic section, understandably that Pre-stack depth migration using Common Reflection Angle Migration has shown significant improvement from the seismic quality and reduce the uncertainty.

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015