| Abstract |
Tianjin is the earliest city of geothermal exploration, development and utilization in China, but Large-scale extraction of geothermal water has caused a rapid decline of water level and increased mining costs in the geothermal field. In order to protect geothermal resources, geothermal reinjection has been required in Tianjin. Reinjection has been widely used in geothermal management, and geothermal production-reinjection doublet was demanded by government. While geothermal production-reinjection doublet systems are new well, most of the old single geothermal well is still mining in urban area which population and construction are very dense. If it is built up recharge wells, mostly constrained economy, construction sites and geological conditions, the implementation is very difficult. The method of geothermal single well integrated or rebuild recharge wells to build production-reinjection doublet systems , which can effectively alleviate the drawdown rate , while applying new technologies such as using heat pump can increase level of geothermal resource utilization, reduce the temperature , and promote the sustainable development and utilization .In recent years we have made a detailed investigation and research in geothermal resource integration and optimization configuration , and also completed a lot of practical engineering cases. In this paper, two successful examples of these projects are mentioned. One is a project of integration in geothermal resources. Two productions well are located in the center of Tianjin city, which also located in the center of drawdown funnel. We converted one production well to recharge well to build production-reinjection doublet system. The ultimate realization of rejection rate is 100%. This is the first successful geothermal resources integrate case in built-up areas of Tianjin. Another is the case of using heat pump technology to improve resource utilization, increasing heating area and constructing recharge well, ultimately geothermal resource utilization rate reaches 100 %, while geothermal tail water has reached 100% recharge. |