|
Mikhail Baykulov, University of Hamburg (Germany)
Heinz-Jürgen Brink, University of Hamburg (Germany)
Dirk Gajewski, University of Hamburg (Germany)
Mi-Kyung Yoon, University of Hamburg (Germany)
|
|
Reprocessing of seismic data of a salt stock family from the North German Basin provided improved seismic images of this area. The Common Reflection Surface (CRS) stack technique was applied to reprocess the reflection data acquired by the hydrocarbon industry in the 1980s. Due to the low fold of these data and the complex geology in the study area severe imaging challenges were encountered when the data were initially processed using conventional CMP stack. The CRS stack technique is particularly suited for low fold data in complex areas since it builds physically correct supergathers even if dipping structures are present. This leads to a considerably improved signal-to-noise (SN) ratio in the CRS stack compared to CMP stack sections.
Kinematic wavefield attributes or CRS parameters computed during the automatic CRS stack are also used to enhance the quality of prestack seismic reflection data. Based on the CRS traveltime formula, partial stacked CRS supergathers are computed. These gathers are regularized and have better SN ratio compared to original CMP gathers. Improved prestack data could be used in any conventional processing tool (e.g., velocity analysis and prestack depth migration) instead of original data, providing enhanced images and better quality control.
Moreover, the CRS parameters obtained during the stack form the foundation for a robust reflection tomography used for velocity model building. These models allowed the application of pre-stack and post-stack depth migration.
Application of the new methods to seismic data from the Jurassic salt plug in the area of Glckstadt Graben show a significant improvement of the image quality of depth-migrated sections. The obtained depth images provided structural details not seen before, motivating an alternative view on the structural setting of the area and an updated look on the petroleum system of the graben.
|
