Deformation behavior of a regional shale formation from integrated laboratory and well data analysis: insights for underground fluid storage in northern Italy

The Po Plain in northern Italy is one of the most populated and industrialized European regions and hosts numerous gas fields, which have been in production for decades. Several reservoirs were subsequently converted into underground storage sites for natural gas (UGS) while others are currently candidates for future storage of CO2 or H2. In all cases, the reservoir caprock confining the fluids underground is the Argille del Santerno formation. The Argille del Santerno is a good-quality shale; it has a thickness ranging from several tens to hundreds of meters and it extends across a large part of the subsurface of the Po Plain. The part of the formation that acts as a caprock for the main reservoirs lies at an average depth of 1200–1500 m.