Heat flux measurements and thermal potential of the Garze geothermal area in the eastern Himalayan Syntaxis

Abstract

A comprehensive heat flux assessment method that includes soil temperature measurement and a chloride-inventory method to evaluate the heat energy of a fissured geothermal area was developed. A novel optimized function was created to deal with the anisotropy of the sequential Gaussian simulation while calculating the conductive thermal energy release, and the accuracy of the result was improved. This method was applied to geothermal potential studies on the fracture-controlled Garze geothermal system in the western Sichuan Plateau, which belongs to the eastern Himalayan syntaxis. The field work was limited to the Garyungo Thermal Area (GYGTA), with an area of 0.91 km2. Soil temperature measurements in the field at more than 400 points and soil thermal conductivity measurements in the laboratory revealed that the conductive heat output accounts for 18.2 ± 0.2 MW. The convective heat output through soil evaporation comes up to 2.8 ± 0.5 MW. The heat output from the hot springs (seepage) accounts for 32.6 ± 6.2 MW. The total heat output reaches 53.6 ± 6.2 MW, with a heat flux of 59 ± 7 W m−2. The heat flux of the GYGTA was consistent with that of the Yangbajing geothermal area and some other high-temperature hydrothermal areas related to volcanic activities; therefore, the high-temperature nonvolcanic-hydrothermal area may produce significant geothermal energy.