High-Resolution Genetic Interpretation of Salt Structure Geometries and Their Near-Diapir Sedimentation

Mohr, Markus¹, Peter A. Kukla¹, Janos L. Urai¹, Georg Bresser² (1) RWTH Aachen University, Aachen, Germany (2) Gaz de France Production Exploration Germany GmbH, Lingen (Ems), Germany

High quality seismic data enable us to present complex outlines of salt structures relat­ed to hydrocarbon systems of the North German basin. Our high-resolution genetic inter­pretation of salt structure geometries and their associated sedimentation improves explo­ration in the subsalt and at the diapir flanks.

We combine 3D and 2D seismic interpretation of pre-stack depth migrated data with 2D & 3D kinematic and geometrical backward modelling. Retro-deformed models for specific time slices characterize the evolution of the salt terrane. This allows us to identify salt move­ment at certain times, to assign possible regional tectonic trigger mechanisms and to uncov­er the relevant salt tectonic processes. We achieved a better resolution of the sedimentary patterns and processes affected by salt movement with additional well-log analysis and compared the results to the regional sedimentary and stratigraphic framework.

We interpreted several salt wedges formed by lateral extrusions during periods with emerged diapirs and reduced sediment accumulation. Paleo-cap rock blocks identified inside the diapirs give evidence of long phases of dissolution. An increased sediment-sup-ply resulted in the onlapping of strata onto the diapir. These halokinetic sequences record­ed the salt-sediment interaction of predominantly non-marine layers and bear a number of potential hydrocarbon traps.

Our better understanding of the structural, sedimentary and salt tectonic evolution and our improved knowledge of the position and amount of salt has effects on seismic model­ling and depth conversion and improves the prediction of potential Upper Permian gas reservoirs in the sub-salt sequences.