Impact of fault rock properties on CO2 storage in sandstone reservoirs

An optimal reservoir for CO2 storage should ideally have high porosity and permeability and exhibit predictable communicational properties. Within sandstone reservoirs, faults and deformation bands may act as barriers and baffles, thus introducing compart mentalization and areas of flow retardation, deviation or acceleration and hence make sub-surface fluid flow less predictable. This will in turn affect the injection rate and the total capacity of the reservoir or compartments. CO2 injection in aquifers creates a fluid pressure increase, which causes changes in the stress state of the aquifer and the reservoir seals. This might affect and reactivate faults, fractures or other deformation structures both within and around the reservoir. (Li et al., 2007). The proposed project aims to increase our understanding of the processes and products of faulting in porous sandstone in order to forecast the distribution and impact of faults and deformation bands on reservoir/aquifer performance and seal properties. Th is will contribute to improved risk assessment when planning and developing potential reservoirs for CO2 sequestration. To achieve these aims, a comprehensive integrated and cross-disciplinary study, which combines analysis of empirical outcrop and subsu rface data, experiments using physical analogues, micro-structural analysis, is called for. The experiments will utilize the existing CIPR database and the state-of-the-art geo-mechanical testing equipments at the Norwegian Geotechnical Institute, support ed by numerical back calculations of the experiments. The final results will be also utilized to verify and, where possible, improve the theories for development of faults and deformation bands.