Conceptual model and potential assessment for the Xiaotangshan geothermal field, Beijing, China

Abstract

The Xiaotangshan low-temperature geothermal field is located about 20 km north of the city of Beijing. The geothermal water has been used for space heating, health spas, greenhouses, fish farming etc. for nearly 30 years. Xiaotangshan is one of the two most exploited and studied geothermal fields in Beijing. The geothermal energy is stored in limestone and dolomite reservoirs. The area identified with the geothermal resource is about 86.5 km2 with three separate reservoirs. The temperature of the geothermal water is 38-70°C. The geothermal water contains SiO2 and other components that are good for human health, and has been used in balneology for more than 300 years. In this paper a conceptual model of the Xiaotangshan geothermal field is developed. An empirical method and lumped parameter modelling are used for production potential assessment of the field. A two-tank lumped model is used successfully to simulate the production and water level history and used to predict future water level changes in the geothermal reservoir. The results show that if the annual production of 87 l/s is maintained, the water level will decline about 19 m in 20 years. This indicates that great emphasis should be placed on management of the geothermal exploitation in this field in the future. Geothermal reinjection is a very efficient method for maintaining reservoir pressure and will be required for sustainable development of geothermal resources in the Beijing area....