Core-scale geophysical and hydromechanical analysis of seabed sediments affected by CO2 venting

•Experimental assessment of CO2 venting through North Sea seafloor sediments.•Joint geophysical-hydromechanical datasets to improve subseafloor CO2 monitoring.•Enhanced porosity and saturation estimates from resistivity and composition.•CO2 venting induces fracturing preferentially in fine-grained seafloor sediments.•CO2-induced fracturing reduces the retention capacity of sediments.