Impact of fault rock properties on CO₂ storage in sandstone reservoirs

The aim of the project is to improve risk assessment when planning and developing potential reservoirs for CO₂ sequestration. This will be achieved by increasing 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 performance and seal properties.
• In-situ measurements of stiffness and permeability of deformed/ faulted sandstone can be used to predict the behaviour of these rocks in response to stress change and/or fluid flow.
• Intense grain crushing in immature and poorly consolidated sandstone could occur at shallow burial depth during deformation independent of mineralogy of the rock, which will locally reduce the permeability of these rocks up to two orders of magnitude.
• The degree of consolidation of sandstone at the time of faulting affects the sealing property of sandstone, resulting in variable CO₂ column heights in fault related rocks.
• Slip surfaces in poorly consolidated sandstone could form conduits to fluid, which might cause a risk of CO₂ leakage in these kinds of reservoirs.
• Faults can change from a baffle to a conduit to fluid flow during different deformation episodes.
• Triaxial experiments on poorly consolidated sandstone and sand are used to understand the mechanism of deformation at different stress levels and predict the final deformation products and their effects on reservoir quality.
• Structural imaging using seismic attribute analysis and analogue fault models help understanding the kinematic and possible reactivation scenarios of faults in Snøhvit Field (Barent Sea).