Characteristics and regionalization of geothermal resources in Beijing

Geothermal resources in Beijing belong to middle-low temperature geothermal resources, which have experienced more than 50 years of concentrated development and utilization. After years of development and utilization, there have occurred some highlighted environmental geological problems in Beijing. In order to reasonably determine the direction of the development and utilization of geothermal resources in Beijing and to build a livable city, this paper summarizes the distributive characteristics of these resources by analyzing the features of geotemperature, hydrogeochemical and stable isotope characteristics. It is found that the geothermal reservoir with the roof temperature higher than 80oC is mainly located in the center of Beijing depression and near the Fengheying in the southern part of Daxing superimposed uplift, and the water chemistry type in Beijing is mainly HCO₃~Na type. The authors also put up zonation for geotemperature regionalization, geothermal resources exploitation and utilization as well as potential regionalization. The geothermal resources protection regionalization is based on the division of the geothermal fields, the characteristics of geothermal resources in combination with the exploitation degree, resource conditions and regional economic development requirements. The region can be divided into restricted mining area, control mining area, mining area and other areas, with the respective area being 378.65 km², 562.88, km², 1612.07 km², and 3722.31 km². The results obtained by the authors are of great significance for understanding the overall characteristics of the geothermal resources and the sources of geothermal water supply and for formulating the geothermal utilization planning. The results also has a guiding significance for protection and exploitation of geothermal resources.