Reservoir evaluation for the Lishuiqiao-Beiyuan geothermal system in Beijing, China : based on a six year production history

Abstract

The Lishuiqiao-Beiyuan geothermal system in Beijing is a low-temperature sedimentary system with conduction-dominated heat flow and a reservoir temperature of about 80°C. Well SR-6, the first geothermal well in the field, was successfully drilled during the winter of 1999-2000 and has been used for district heating since November 2000. In order to make the most of geothermal resources in this area, three more geothermal wells were drilled in 2001-2002, of which well BY-1 has been used for district heating for two years now. Water level and production data from wells SR-6 and BY-1 and water level data from three observation wells have been utilized for simple reservoir modelling including lumped parameter modelling. The results indicate a system area on the order of 160 km2 and a permeability-thickness as high as 80 Dm in the centre of the field. The permeability decreases towards the edges of the field and the average permeability is estimated to be around 10 Dm. Future water level predictions for both wells SR-6 and BY-1 show clearly the benefits of reinjection. Well SRG-1 is the reinjection well for SR-6, but the distance between the wells is only 230 m and cooling predictions show that there is considerable danger of cooling in SR-6 due to reinjection into SRG-1. Reinjection wells should, in general, be located at a greater distance from production wells. The Beijing government needs to put great emphasis on improved management of the geothermal resources under the city, including improved monitoring and increased reinjection.