The Bavarian Petrophysics-Database

The Bavarian Geological Survey is developing a comprehensive petrophysical database for characterization of the underground potential. It includes thermal, hydraulic, elasto-mechanical, and electromagnetic rock properties, from samples from our drill core repository, containing more than 90,000 m core/cuttings material.

A standardized internal lab workflow allows for the determination of several parameters in a single sample, including thermal conductivity and diffusivity (under dry and saturated conditions), bulk and grain density, porosity, and magnetic susceptibility. Selected samples are further analyzed for ultrasonic velocities, uniaxial compression, mineralogy (XRD), and geochemistry (XRF).

Currently, the database features over 6,500 samples from 70 drill cores, representing more than 280 geological (sub-)units and 70 lithological types described with different levels of detail and ranging from 0.2 to 5,400 m depth. All data must fulfill five minimum criteria and are georeferenced for 3D geological modeling at different scales. For these models, two distinct data generalization approaches are used: a “Top-to-Bottom” approach for rapid estimation using medians for lithologies and geological units, and a “Bottom-to-Top” weighted averaging, which accounts for the lithological/geological heterogeneity of each model layer.

The database plays a key role in current LfU projects, especially in geothermal reservoir modelling in the Bavarian Molasse basin. Its usage extends to research on CO₂ capture and storage, search for a radioactive waste repository, as well as hydrogen production and storage. Public data access to this database via the “UmweltAtlas Bayern” online platform is under development in accordance with the German law (Geologiedatengesetz, 2020).