Staßfurt: fluid transport in rock salt - spatial distribution and dynamics

This project is part of the scientific joint venture "Dynamics of flooded or drowned salt mines and their overlying rock" funded by BMBF and coordinated by BGR.

This scientific joint venture revolves around the massive damages caused by flooded salt mines under the city of Staßfurt (Saxony-Anhalt). Salt mining is conducted extensively at Staßfurt since the middle of the 19th century. Due to the lack of geotechnical experience at that time meanwhile all salt mines are lost by massiv influx of water. The uncontrolled outwash of salt in the underground by intensive inflow of groundwater persists till this day. As a consequence the downtown area has sagged partially up to 7 meters, sink holes occured and wide areas of the town had to be teared down and turned partially into a lake. Further severe damages are anticipated.

This joint venture consists of several research institutions, universities and companies examining broadly the current situation to estimate the ongoing processes in the area. Staßfurt shall gain some planning reliability for the future on this way.

Our contribution is to examine the dynamics and mass transport of groundwater inside drilling cores taken from the salt rock and to visualise and quantify flow patterns and mass transport at the milli- and microscale. For this purpose we conduct flow through experiments with radioactive tracered water which we image by means of positron-emission-tomography (PET).

Positron emission tomography in geosciences

PET is mainly for financial reasons rarely applied in geosciences. Accordingly only few work was done on this topic so far.
The Reactive Transport Division of the Institute of Radiochemistry of the HZDR is examining the possibilities this technology offers for geosciences now for many years. For this purpose a commercial MiniPET scanner is available. Drilling cores and sediment columns up to 10 cm in diameter can be scanned with a spatial resolution of 1.15 mm and a time resolution of 60 s. A couple of isotopes are available as PET nuclides that can be used as inert tracer compounds accordingly to the posed problem. Radio tracer concentrations of 10-8g/l can be easily detected.

Cooperation partners

The Institute of Geosciences of the University of Mainz generates high resolution CT-data sets of the inner structures of these drilling cores in order to match the measured flow patterns with the structure. Additionally particle tracking simulations of the flow patterns are conducted that base on the Lattice-Boltzmann method. The alignment of simulations with PET measurements shall lead to a wider understanding of the ongoing processes as well as to possible strategies for upscaling to the kilometer scale.

Funding: Bundesministerium für Bildung und Forschung (BMBF)

Project executing organisation: Karlsruher Institute of Technology (KIT)

Coordination: Bundesanstalt für Geowissenschaften und Rohstoffe (BGR)

Literature: M. Wolf; Visualisierung und Quantifizierung der Fluiddynamik  in Bohrkernen aus dem Salinar und Deckgebirge des Raumes Staßfurt mittels Positronen-Emissions-Tomographie. PhD-thesis. Faculty of Physics and Geosciences, Leipzig University, 2010.


Dr. Johannes Kulenkampff (HZDR)