Investigating gas shows and migration pathways to mitigate drilling risks of deep geothermal wells in Eastern Bavaria

This abstract describes one of the work packages of TUM.GTT´s GeoChaNce.Bayern research project, funded by the Bavarian Environmental Agency. A shallow seismic campaign was conducted near the eastern Bavarian town of Simbach am Inn. The poster will provide an overview of the initial results of the shallow seismic campaign and an outlook on the ongoing work on seismic interpretation in the eastern part of the North Alpine Foreland Basin in Germany.

Deep geothermal energy has the potential to replace fossil-fueled heating in Bavaria. However, an increase in geothermal site construction and, thus, drilling activity is necessary to reach the goal of supplying 25% of the building heat used in Bavaria. Drilling efficiency and safety are often compromised by the subsurface's challenging geological and geomechanical conditions. One critical aspect of ensuring a safe drilling process is mitigating the risk of encountering uncontrolled gas influxes, also known as kicks. To do so, potential gas reservoirs in shallow and deep stratigraphic layers should be identified and mapped prior to drilling. An additional step is to reconstruct the migration history of hydrocarbons from source to surface, in order to understand the likelihood of gas occurrence. Here we integrate newly acquired shallow and legacy deep seismic reflection data, well logs and documented drilling incidents in the Altötting-Simbach area, which represents a shallow and deep gas-prone area in the eastern Bavarian part of the North Alpine Foreland. Comprising a large fault-bounded basement high (Landshut-Neuötting High) and basement trough (Giftthal trough) as well as proven shallow and deep natural gas deposits, makes the Altötting-Simbach area an ideal candidate to study gas migration in the North Alpine Foreland Basin. We will introduce the dataset, initial interpretations, and planned workflows to unravel the gas migration history and provide context for drilling risk mitigation in deep geothermal energy production in the North Alpine Foreland Basin.