Storage Behaviour (2009-2013)
Overall objective: The main objective was to provide an improved physical and practical basis for determining best practice for CO2 storage.
The various trapping mechanisms for CO2 in the underground are structural trapping (i.e. existence of a cap rock), capillary trapping, dissolution into brine, and so-called chemical trapping. Dissolution is a generally an important medium to long time scale mechanism, potentially removing all possibilities of long term leakage from a storage site. The work in BIGCCS improved the basic understanding and especially the timing of this trapping mechanism, which is important for qualification and storage safety.
New mathematical results on gravitational driven instabilities of CO2 – brine solutions. In particular, the instability operator was explicitly derived, and novel properties on the spectrum of this operator highlight properties of the onset of convective mixing. Upscaling of dissolution mechanisms, as well as experimental and numerical studies of convective mixing in homogenous and heterogeneous porous media were also studied in this Task.