Search Results (2)

The coal-dominated energy structure in the Beijing–Tianjin–Hebei region has caused serious air pollution and contradicts the construction of a clean, low-carbon, safe and efficient energy system. Substituting geothermal energy for fossil energy such as coal can effectively alleviate this problem. Located in the hinterland of the Beijing-Tianjin-Hebei region, the Jizhong Depression is rich in geothermal resources and has great development potential, though the degree of current development and utilization is not high. Vigorously developing geothermal energy can not only effectively alleviate the air pollution problem in the Beijing–Tianjin–Hebei region, but also optimize the regional energy structure. Geothermal reservoir temperature determines the development and utilization value of geothermal resources, and accurate evaluation of the geothermal reservoir temperature of geothermal resources can provide a reliable basis for the subsequent development of geothermal resources in the Jizhong Depression. Aiming at the commonly used sandstone geothermal reservoir and carbonate geothermal reservoir in the Jizhong Depression, this paper collected 24 sandstone geothermal reservoir geothermal fluids and 14 carbonate geothermal reservoir geothermal fluids in the central-southern area of the Jizhong Depression and a water chemistry test was carried out. According to the test results of water chemistry, the temperature of the geothermal reservoir is estimated by using the cation geothermometer, the SiO₂ geothermometer and the multi-mineral equilibrium method, and it is compared with the actual temperature measurement results of the boreholes. The results show that the direct use of a geothermal geothermometer for calculation will cause large errors. Through water–rock balance analysis, the use of a Na-K-Mg balance diagram, SiO₂ and 1000/T relationship diagram and Na/K and 1000/T relationship diagram can determine whether the geothermal fluid is suitable for the geothermometer, which can effectively reduce the error. The chalcedony geothermometer in the central and southern part of the Jizhong Depression is the most suitable. The multi-mineral balance method, the Na-K geothermometer and the K-Mg geothermometer have also achieved good results, while the quartz and Na-K-Ca geothermometers are not suitable for the south-central Jizhong Depression area. Full article

The Tatun geothermal system is located in Northern Taiwan and is hosted by the Tatun volcano group (TVG). The variation in the geochemical composition of thermal waters is considered to be an important indicator of volcanic activity. In this study, we analyzed the chemical and isotopic compositions of hot springs in the TVG. A chemical and multicomponent geothermometer was used to estimate the reservoir temperature, and hydrogen and oxygen isotopes were used to determine the source of the thermal water. The presence of thick andesite and fractures allowed the formation of different type of springs in the center close each other with lower temperatures and acidic springs with higher temperatures at the northeast and southwest sides of the Tatun geothermal field. The saturation index showed that the concentration of SiO₂ in the thermal water was controlled by quartz. The multicomponent geothermometer indicated a reservoir temperature between 130 °C and 190 °C, and the geothermal water in Longfengku, Lengshniken, Matsao and Szehuangping may have mixed with shallow groundwater. Isotope data indicated that the stream water and groundwater originated from meteoric water, and the spring water showed a significant oxygen shift, due to water–rock interaction and evaporation. The isotopes of the fluid in the TVG are also affected by the seasonal monsoon. These results can serve as a reference for designing a conceptual model of the spring in the Tatun geothermal system. Full article