Data-driven Hydraulic Barriers Delineation and Migration Pathway Detection within the CO2 Geological Storage of Sleipner

The deep saline aquifers constitute the strongest storage capacity for CO2 storage among the portfolio of possible geological opportunities. The upward and lateral migration of CO2 after being injected into such formations depends (i) on permeability and porosity of the storage formation, (ii) on the potential hydraulic barriers. At Sleipner, the CO2 is injected inside the Utsira formation, where hydraulic barriers correspond to thin intra-shale layers identified by logs without information on their lateral continuity. Furthermore, conventional interpretations of 3D seismic data cannot provide better constraints because the intra-shale layer thickness is smaller than seismic resolution. The proposed method consists in refining intra-shale layer delineation using 4D seismic data in the area invaded by CO2, but also in the Utsira formation part covered by time-lapse seismics. The shale bottom delineation is consistent with 3D-detailed geometry of the CO2 plume and with independent observations of shale at a well. To our knowledge such a detailed 3D description of the Utsira hydraulic barriers has not been published before. Hence, the intra-shale layer discontinuities, allowing the upward migration of CO2, can be identified and could be integrated, in further steps, in the geological static model, unavoidable stage for an efficient dynamic flow simulation.