Geomechanical Assessment of Flow Barriers Observed from 4D Time-lapse Survey for CO2 Storage in Snøhvit Field

This study assesses the characteristic of flow barriers observed from 4D time-lapse survey for CO2 storage in Tubåen Formation, Snøhvit field by geomechanical analysis. The flow barriers are hypothesized as structural compartments (e.g. sub-seismic faults) and then the stability of faults are assessed by both numerical and analytical approaches. The analytical approach results in stable condition of hypothetical sub-seismic faults. However, stability seems to be underestimated mainly due to simplified assumption of the analytical approach. The numerical approach estimates failure of flow barriers that can cause communication even outside the flow barrier, which seems to be inconsistent with the seismic 4D observation. The numerical estimation may imply that the observed flow barrier is a feature of depositional flow channel rather than a structural compartmentalization. However, the assessment was carried out based on conservative scenario. Further work on realistic implementations of complex fault structure into the analysis would be important for better assessment of fault integrity and characterization of flow barrier.