Surface and Subsurface Behavior of a Natural Gas Storage Site over Time: The Case of the Cornegliano Gas Field (Po Plain, Northern Italy)

Foredeep basins often host significant natural gas reservoirs within siliciclastic successions, as exemplified by the Po Plain (Northern Italy), one of Europe’s largest foredeep basins. Here, numerous depleted gas reservoirs have been successfully converted into underground gas storage (UGS) facilities. For safe and efficient storage operations, detailed reservoir characterization and continuous monitoring of surface and subsurface effects are crucial. This study investigates the Cornegliano Laudense reservoir during its first 5–7 years as a UGS facility, employing an integrated monitoring approach that combines traditional methods (InSAR for surface deformation, microseismic monitoring) with innovative techniques (Pulsed Neutron Log-PNL). The results clearly illustrate and quantify the significant increase in storage capacity over a relatively short operational period, primarily driven by the progressive displacement of formation water by injected gas. Despite increased stored gas volumes, monitoring revealed no adverse effects on surface stability or subsurface seismicity. This integrated methodology demonstrates substantial potential for refining predictive models, optimizing storage efficiency, and enhancing sustainable management practices for underground gas storage operations.