Underground H2 and CO2 storage

The Reservoir Technology department approaches geological hydrogen storage from the vantage point of their substantial expertise in CO2-storage and reservoir fluid flow behavior. We combine fluid flow experiments under in-situ reservoir conditions with geochemical reservoir analysis and numerical modelling to address key geological challenges to hydrogen storage, such as reservoir and caprock integrity, hydrogen injectivity and reproducibility, and the contamination of stored hydrogen due to geochemical and biological processes. While our prime focus is on hydrogen storage in porous reservoirs, which are more available around Norway, we do also address storage in salt caverns and other cavern storage options.

Due to the size of the hydrogen molecule, the integrity of shales and similar caprocks, and the sealability of fractures are key challenges for hydrogen storage in porous reservoirs. Likewise, the sealing-quality of (OPC-based) wellbore sealants to hydrogen needs to be tested and ensured. These challenges require experimental research exposing various relevant caprocks and sealants to a flow of hydrogen under in-situ conditions, to study permeability and other effects. Our Porous Flow laboratory aims to measure the permeability of natural and man-made rock-like materials to hydrogen under a range of relevant PT-conditions, with and without water. Furthermore, we can also address geochemical interactions between hydrogen and selected minerals/phases that may impact both caprock or seal integrity, and hydrogen purity.

As geochemical and biological processes may affect the purity of geologically stored hydrogen, such processes need to be studied thoroughly, and may need to be monitored during the lifetime of a hydrogen store. Our analysis laboratory has already built a considerable expertise in analysing low concentration impurities in hydrogen generated during hydrogen production, and this expertise can be used to measure and monitor impurity generation due to underground processes. Furthermore, stable isotope techniques may be used to pinpoint reactant sources, and to identify the processes that lead to impurity generation.

Numerical modelling extrapolates empirical observations on the flow behavior of rocks and fluids to length and time scales (and conditions) beyond what can be achieved in the laboratory, and thus forms an important part in our research on geological hydrogen storage. Models developed for CCS and other reservoir storage and production technologies, for example to identify potential leakage mechanisms and to quantify injectivity and productivity, will readily be adapted to hydrogen storage integrity and flow assurance.