Simple experimental setup to study effects of microbial activity on rock permeability important for hydrogen storage

Effects of microbial activity on permeability of porous rock is a significant research topic in the context of underground hydrogen storage. However, the introduction of microorganisms into conventional experimental setups for permeability measurements under in situ pressure and temperature conditions might cause several risks for the outcome. Maintaining sterile conditions is important as well as the exclusion of oxygen and the avoidance of toxic materials such as lead foil. Thus, careful planning and consideration of the experimental set up is crucial to avoid incorrect assessment of microbial rock interactions. This study presents the interdisciplinary development of a simple experimental setup to gain basic knowledge on microbial rock interactions. The system was successfully used to introduce microorganisms into porous rocks while the anaerobic microorganisms stayed alive and active and no contamination was observed. At the same time, the setup was sensitive enough to detect a permeability reduction induced by the introduced microorganisms. Consequently, this experimental setup helps gaining fundamental knowledge needed for more complex experiments e.g. in high pressure Hassler cells where in situ pressure, temperature and flow conditions can be simulated.