PERBAS: An International Project to Study Potential Sites for the Permanent Offshore Storage of CO2 in Marine Basalts

CO₂ neutrality by 2045 requires increasing the currently worldwide achieved CO₂ storage volume (40 Mt/y) to the order of tens of Gt/y. With current storage techniques, CO₂ often remains in the gaseous phase, thus, free to spread underground risking unwanted leakage in the distant future. As an alternative, the mineralization of CO₂ in basalts, where the vast majority (>90%) of the carbon is mineralized and fixed in carbonates within two years, offers a permanent safe storage as a solid (e.g. CarbFix, Iceland).
The international joint project PERBAS (ACT4) with partners from Norway, USA and India aims to pave the way for the commercialization of large-scale, permanent CO₂ sequestration into marine basalt complexes off the coast of Norway and India. The project seeks solutions for reservoir selection, CO₂ transport, injection and monitoring. PERBAS will investigate the feasibility of supercritical CO₂ injection, using water in the pore space, in order to avoid the requirement to inject 20 t of water for 1 t of CO₂. This would have the additional advantage that supercritical CO₂ would be associated with a free gas phase, which allows the application of geophysical remote sensing for monitoring thereby reducing the number of monitoring wells required.
Within the German sub-project CO2PR, geophysical field data (seismics and electromagnetics) will be collected during a research cruise offshore Norway currently planned for 2024. The resolution and efficiency of associated inversion techniques will be made usable for large-volume (Gt) reservoirs and complemented with new AI methods to identify signals suitable for monitoring.