The deeper subsurface of Lower Saxony – Developing a generalised 3D geological model from heterogeneous and inconsistent data

The creation and application of 3D geological models has become increasingly important within the geological surveys in recent years. In the joint project TUNB (Tieferer Untergrund Norddeutsches Becken - Deeper Underground North German Basin), the geological surveys of northern Germany together with the Federal Institute for Geosciences and Natural Resources (BGR) created a coordinated and largely border-harmonised 3D geological model of the North German Basin for their respective state areas. The objective of this presentation is to describe the approach to develop a generalised 3D geological model from the base Zechstein to the Tertiary of Lower Saxony based on heterogeneous and inconsistent data within this project. The data basis for the current model was the predecessor model GTA3D, digitally available borehole data, depth migrated 2D and 3D seismic data and supplementary data such as thickness and structural maps of lithostratigraphic units. 3D geological modelling was carried out with Emerson SKUA-GOCAD, taking into account the project-related generalisation specifications and geological plausibility. The problem of inconsistencies occurring in the input data due to their different sources, quantity, and quality could not be solved by automated procedures. Instead, this was often subject to the geological expertise of the modeller, who took into account the regional geological conditions to weight the data and create a model that is as free of contradictions as possible. We demonstrate how the integration of new data led to changes in the geometry of salt structures and lithostratigraphic horizons with respect to the predecessor model.