Geological and geophysical investigation of CO2 storage site Smeaheia in the northern North Sea

For a subsurface CO2 storage it is imperative to evaluate the reservoir, seal and overburden viability to avoid any storage-related problems, or subsequent leakage risks. Whereas, in case of a hydrocarbon trap, the presence of oil and gas itself validates a working reservoir, seal and overburden system. The upper Jurassic Sognefjord Formation is a potential CO2 storage formation overlain by the Heather and Draupne Formations considered to be the cap rocks in the Smeaheie area within the northern North Sea. In this study, we extracted spectral decomposition and similarity attributes at various levels from the top reservoir to the sea floor from a 3D seismic survey covering the area. The attributes facilitated to identify various fault systems and surface features. A prestack seismic inversion was also carried out to obtain elastic property cubes, i.e. acoustic impedance, Vp/Vs ratio, and density. These elastic properties showed changes as a function of compaction and will be used to build a geomechanical model in the next stage of the study. The geological and geophysical properties derived from the seismic attributes, well logs and laboratory measurements of cores/cuttings will be used to calibrate the model.