Open-Source InSAR data to detect ground displacement induced by underground gas storage reservoirs

This study investigates ground displacement in Underground Gas Storage (UGS) areas using Interferometric Synthetic Aperture Radar (InSAR) techniques applied to free and open-source Sentinel-1 data extracted from the European Ground Motion Service (EGMS). Three UGS facilities in Lower Saxony, Germany, are examined to understand how reservoir type plays a key role in surface deformation. In pore storage reservoirs, such as those at Uelsen and Rehden, UGS operations cause pressure changes propagating to the surface and resulting in observable seasonal uplift and subsidence. Conversely, in the Etzel salt caverns, subsidence is inherent, with deformation rates influenced by the balance of gas withdrawal and injection. The analysis includes mapping the displacement velocity in both ascending and descending geometries, as well as the vertical and horizontal components of the displacement. The extracted time series of ground displacement reveal temporal relationships between UGS operations and surface fluctuations. By integrating InSAR data with the UGS operational records, this study highlights significant differences in ground displacement behaviours between geological settings. The Etzel site exhibited the most significant deformations, while the Uelsen and Rehden sites showed seasonal 'breathing' patterns. This work represents a novel application, filling a significant gap in the literature by using free and open-source data to investigate UGS activities over different geological contexts. The results highlight the complexity of the interactions between UGS operations and the environment, emphasising the need for further research to improve the sustainable management of subsurface resources.