The Influence of the Salt Diapir Büsum on the Thermal and Maturity History of Surrounding Sedimentary Rocks: A 3-D Numerical Modeling Study in the North German Basin

Rodon, Sabine, Ralf Littke, Technical University of Aachen, Aachen, Germany

A special problem in basin modeling is the widespread occurrence of salt structures in hydrocarbon provinces. It is well known that the petrophysical properties of salt differ from those of other sedimentary rocks. In particular salt has a much higher thermal conductivity and therefore can significantly affect the temperature and maturity distribution in a sedimen­tary basin as well as the timing of hydrocarbon generation. The central part of the North German Basin is characterized by a multitude of huge salt diapirs derived from Rotliegend and Zechstein salt. In a 3D numerical modeling study we analyzed the influence of such a salt diapir on the temperature and maturity evolution of the surrounding sedimentary rocks. For the calibration of the model we used temperature and vitrinite reflectance data from 7 wells, located at different distances to the salt diapir. At the western flank of this salt diapir the large Mittelplate oil field is located. The reconstruction of this oil field was also availed to proof the correctness of the chosen model. We want to show that sedimentary basins comprising salt structures have to be modeled in 3D in order to obtain correct results for the thermal and maturity history of the basin. Furthermore we also want to emphasize the importance of correct physical rock properties, especially thermal conductivities in model­ing temperature histories. For this purpose thermal conductivities were measured for parts of the sedimentary sequence and finally implemented into the model.