Conditions for the enrichment of karst hydrothermal resources in Bohai Bay Basin

Drilling for karst hydrothermal resources in eastern China has posed challenges, including disparities between the temperature and yield of geothermal water. It is evident that relying solely on geothermal anomalies or indications of karst reservoirs is inadequate for the exploration of karst hydrothermal resources. This study seeks to elucidate the cause of geothermal sweet spots by analyzing the interplay between geothermal anomalies and karst reservoirs and the underlying geological conditions for karst hydrothermal enrichment. Key findings include: (1) the Bohai Bay Basin has been geologically favorable for the development of karst hydrothermal resources since the Mesozoic era; (2) the karst hydrothermal enrichment varies significantly between the basin’s margin and its interior. On the basin margin, the enrichment is largely driven by groundwater activity and faults, particularly where faults facilitate the upwelling of geothermal water. In contrast, within the basin’s interior, karst hydrothermal resources are predominantly influenced by buried hills and are especially enriched in areas facilitating the discharge of deep geothermal waters.