Revisiting the structural setting of the Glueckstadt Graben salt stock family, North German Basin

Abstract

Reprocessing of seismic data of a salt stock family from the North German Basin provided new insights into the structural evolution 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 super gathers even if dipping structures are present. This leads to a considerably improved signal-to-noise ratio in the CRS stack compared to CMP stack sections. Moreover, the CRS stack 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. The obtained depth images provided structural details not seen before, motivating an alternative view on the structural setting of the area. The image of the Jurassic salt plug indicates tectonics similar to observations in the Allertal region, where reverse faulting plays a major role in the evolution of the salt structures. As a consequence, shortening of the Mesozoic strata was included into the revised interpretation of the Glueckstadt Graben area. The new depth images also allowed an updated look on the petroleum system of this graben, which indicates new possible exploration targets.