Geochemical study of the Xianyang low-temperature geothermal field, Shaanxi province, China

Abstract

Xianyang geothermal field, located in the Shaanxi province, is characterized by relatively higher temperature and discharge of geothermal water compared to other low-temperature geothermal fields in China. This study involves the application of geochemical methods to estimate the properties of thermal water from Xianyang. Geothermal water from fifteen wells, divided into three groups based on the distance from the North Wei River fault, is classified according to the Cl-SO4-HCO3 triangle diagram, as ranging from mature geothermal water to peripheral waters. Quartz and Na/K geothermometers suggest subsurface temperatures in the range of 76-118°C. Some scaling potential is observed for calcite and magnesium-silicates. Application of a mixing model concludes that mixing with colder water is not obvious. The reservoir is responding to increasing utilization, as changes in the chemical content of the fluid are observed without changes in the measured wellhead temperature.