Geothermal Reinjection in Tianjin, China

Abstract

Tianjin is a big city with abundant low- and midgrade- temperature geothermal resources used for space heating, greenhouses, spas, and domestics hot water. Large-scale extraction of geothermal water has caused a rapid decline of water level in the geothermal wells. In order to protect geothermal resources, geothermal reinjection has been required during the development of geothermal resources in Tianjin since 1999. At present, 53 reinjection wells have been drilled, and the annual reinjection amount is 5.62 million m3/yr. This accounts for 22.5% of total production from the reservoir in 2008. As indicated by temperature and pressure monitoring in geothermal reservoirs, the water level close to reinjection wells declines much slower than in other parts, and no temperature changes have been observed in the surrounding production wells yet. The experiences and problems related to reinjection in Tianjin are discussed.