Assessment of geothermal resources in the Lishuiqiao area, Beijing, China

Abstract

The Lishuiqiao geothermal system is a low-temperature sedimentary system, with conduction dominated heat flow and a reservoir temperature of about 80?C. The first geothermal well in the area, SR-6, was successfully drilled during the winter of 1999-2000. It has been used for space heating since November 2000. In order to reduce air pollution resulting from the use of coal boilers, the Beijing Government encourages the use of environmentally friendly energy to heat houses. A plan has been made to develop the geothermal resources in the Lishuiqiao area to provide heating and domestic hot water for some inhabitants in the area. Three more geothermal wells have been drilled successfully, but have not been utilized yet. Available data from well SR-6, including well test data and 2 years for production and waterlevel data, provide the basis of model development and calculations. Two lumped parameter models have been set up and used to estimate the properties of the Lishuiqiao geothermal system and to calculate predictions for different production scenarios. Based on the models, the system acts like a closed geothermal reservoir with a surface area of about 110 km2, a volume of about 55 km3 and a reservoir permeability-thickness varying between 20 and 68 Darcy-m. According to conservative water level predictions of a closed three-tank model, the production potential of the system is about 14 l/s without reinjection, 28 l/s with 50% reinjection and 56 l/s with 75% reinjection, on the average for the next 10 years. Reinjection will, in fact, be essential for sustainable...