Influence of Injection Well Location on Hydrogen Storage Capacity and Plume Migration in a Saline Aquifer: A Case Study from Central Poland

The efficiency of underground hydrogen storage (UHS) in an anticlinal dome structure in a saline aquifer largely depends on the geometry of the dome structure and the placement of injection wells, which determine both the dynamic capacity and the migration of the gas plume. In this study, we aimed to assess the impact of well location within the Jeżów anticlinal dome structure (central Poland) on storage capacity and hydrogen plume migration. A geological model of the structure was developed and used in TOUGH2 (version 2.0) software to simulate nine injection scenarios with different well placements. The results indicate that storage capacity increases with both the secant dip angle relative to the top of the dome structure and the tangent dip angle at the well location, reaching a maximum in areas with the steepest dip. During injection, the hydrogen plume migrates upward toward the top of the structure; afterwards, it gradually stabilizes and partially redistributes toward the top of the dome structure. Injection wells located in steeper parts of the anticline promote upward hydrogen migration, which may limit hydrogen recovery during the withdrawal phase. This study confirms that both structural dip and well placement are key factors determining UHS efficiency.