Analysis of controlling factors of salt window formation: A case study of typical basins on both sides of South Atlantic

Salt windows are critical pathways for hydrocarbon migration. Whether they are developed or not determines whether sub-salt hydrocarbons can migrate upward, influencing reservoir formation and exploration in supra-salt domains. In order to analyze the formation and controlling factors of salt windows, this study focuses on Lower Congo Basin and South Gabon Basin, which exhibit significant differences in supra-salt hydrocarbon enrichment, and compares them with Campos Basin. By integrating seismic data, well logging, and hydrocarbon discovery data, differences in residual salt composition, supra-salt fault characteristics, and host rock properties among the three basins are analyzed to assess their impacts on salt window formation.The study indicates that: Residual salt dominated by anhydrite (rather than halite) facilitates salt window development due to its higher brittleness, requiring greater thickness to form a continuous sealing layer. Supra-salt normal faults (compared to reverse faults) enhance extensional thinning of salt and promote salt window formation. Host rocks with favorable physical properties strengthen hydrodynamic conditions and increase water flow rates, accelerating salt dissolution and aiding salt window development. These findings provide guidance for supra-salt hydrocarbon exploration in the studied region.