CHARACTERISTICS OF UPPER PALEOZOIC AND MESOZOIC SEDIMENTS AS DEPICTED FROM BOREHOLE EVIDENCE IN THE GERMAN NORTH SEA BASIN

The joint research project “Geopotential of the German North Sea” (GPDN) determine and supply geological basic information with regard to a better understanding of the deeper underground and its potential usage. Based on available maps from Baldschuhn et al. (2001) together with the first mapping of the northwest part of the German North Sea, a geological 3D model is constructed within the project that serves as framework for a 3D facies model. The aim of our study will be the elaboration of a 3D facies model to gain a better understandig of the spatial distribution of reservoir and seal rocks in different stratigraphic levels in the deeper subsurface.

As a first step, we selected a suite of boreholes from the eastern part of the German North Sea that comprise Permian and Mesozoic formations to construct 2D profiles through the study area. For stratigraphic correlation we use markers that include both, information from well descriptions and seismic interpretation. Furthermore, we show the reconstruction and interpretation of the lithology based on cuttings and core descriptions as well as other available data like geophysical logs (GR and Sonic).

The selected cross section runs from NE to SW from the Westschleswig Block to the border of the Netherlands. The basis of the Upper Rotliegend formation as the deepest existing stratigraphic marker in the wells is located at depths between 4000 and 5200 m. Jurassic sediments are missing throughout the section. The greatest variation of thickness can be observed in the Upper Rotliegend, Zechstein and in the Keuper deposits. Based on the situation in the centre of the Southern Permian Basin the facies differs considerably in time and only in minor part in the stratigraphic extent.

Baldschuhn, R., Binot, F., Fleig, S. & Kockel, F. (2001): Tectonic Atlas of Northwest Germany and the German North Sea Sector. – Geol. Jb., A 153, Hannover.