Abstract:

Temperatures of geothermal reservoirs are calculated in 4 ways with data of 49 thermal water samples in this study. Taking thermal groundwater of Tianjin as an example, calculation of temperature of geothermal reservoirs under regional geologic conditions is discussed. In addition, mixing models are established in the sample which is doubted to have mixed with cold water. The results indicate that conditions for applications of various geothermometers are different from each other. These geothermometers are applied to calculate temperature based on field data. However, the results obtained are quite different. The Na-K-Ca diagram and the lg（Q/K）figure are used to examine the mineralfluid equilibrium.Lost of steam and mixture with other water are also needed to be considered. The reservoir temperature estimated at 8 geothermal wells in the Tianjin area ranges from 83 to 120 ℃. The reservoir temperature before mixture estimated at the Sanyuanli well in Guangzhou is 79.3 ℃ and the percentage of mixed cold water is 83%.

Key words: geothermometer, chemical equilibrium, temperature of geothermal reservoir, thermal groundwater, hot spring, the Tianjin area