Research and Progress of Geothermal Reinjection in Beijing, China

Abstract

Since geothermal fields were found in the 1970’s in urban areas of Beijing, a variety of tests on geothermal reinjection have been carried out in geothermal production wells drilled in urban and suburban areas. Tap water, shallow, cold groundwater, factory wastewater and geothermal backwater after heating have been used for the tests and a certain amount of experience has been accumulated. Productive reinjection has been gradually implemented and expanded in the Xiaotangshan geothermal field since the 21st century. At present, more than 36.5%[1] (up to 63%[2]) of geothermal water can be reinjected in this geothermal field. The pressure (water level) of geothermal reservoir has gradually risen since 2005, which was higher than that of 2004[3,4]. Geothermal reinjection can save costs for geothermal exploration and significant environmental benefits have been achieved. Research on the mechanism of geothermal reinjection has been carried out since the 1970’s, but there was only a partial understanding at the early stages of the small-scale pilots. With the implementation of large-scale reinjection, progress has been made on water balance, heat balance and geochemical aspects. On this basis, recommendations have been made on geothermal reinjection in Beijing in the future.