| Abstract |
Carbonate geothermal reservoirs, characterized by widespread distribution, high discharge capacity, and favorable reinjection conditions, have become a key target for geothermal resource development. However, the karst geothermal reservoir system in the Fanxian geothermal field exhibits significant heterogeneity, leading to substantial disparities in productivity among multiple geothermal wells and severely restricting efficient regional exploitation. This study systematically investigates the hydraulic characteristics and development potential of the karst geothermal reservoir in the Fanxian Geothermal Field using sodium fluorescein tracing experiment technology. The results reveal that the reservoir system contains multiple flow channels with distinct permeability differences. The dominant flow pathways, controlled by fault structures, exhibit an apparent velocity of up to 30 m/h, significantly higher than other regions in the study area. In contrast, low-permeability zones, influenced by the burial depth of the Ordovician strata, show poor connectivity due to limited karst development, with the lowest apparent velocity of only 2 m/h. By integrating pumping test data and tracer response characteristics, the dominant flow direction demonstrates stronger recharge capacity and water abundance, offering higher development value. Conversely, the low-permeability zone has weaker water production and constrained recharge conditions, resulting in relatively limited development potential. Additionally, it is recommended that the direction of future geothermal well placement in the Fanxian geothermal field should avoid being parallel to the fault strike to prolong the thermal breakthrough arrival time. |