Towards an integrated seismostratigraphic framework in the Bavarian part of the North Alpine Foreland Basin: Implications for geothermal exploration

The Bavarian part of the North Alpine Foreland Basin (NAFB) is highly relevant for geothermal exploration, especially amid recent play developments, highlighting the importance of an integrative geological and geophysical approach. Our work focuses on establishing a robust seismostratigraphic framework for the Bavarian NAFB using an unprecedented dataset consisting of digitised (vintage) seismic and well log data.

Based on this unique data set, we interpreted and correlated well logs and identified important seismic reflectors across the NAFB using seismic-to-well ties and synthetic seismograms, refining seismostratigraphic concepts from previous models such as GeoMol [GeoMol Team – Project Report (2015)]. Our study incorporates considerations of different depositional facies, focusing on the continuous traceability of major reflectors throughout the basin. We identified five major Tertiary reflectors that can be consistently tracked across various lithological and facial boundaries and follow major basin-wide unconformities. Especially the main reflectors identified within the complex Egerian successions and their ability to be traced across different lithostratigraphic units (i.e. Lower Freshwater/Brackish/Marine Molasse), serve as an example of how the reflectors are partially independent from stratigraphic boundaries and their varying facies distributions. Instead, the presence of major seismic reflectors in the NAFB is rather determined by basin-wide unconformities, whose distinctive seismic signatures serve as a basis for consistent identification across the basin.

Our work provides a fundamental step towards an integrated seismostratigraphic framework for the Bavarian NAFB, aiming for a coherent approach of seismic interpretation in industry, academia and authorities, thus promoting standardized methodologies for future (geothermal) well development.