Study On Key Problems Of Geothermal Reinjection In Xiaotangshan Area,Beijing

Geothermal Reinjection is an important method of realization of geothermal sustainable development. It can make people use heat and no water from geothermal resource, which not only can protect geothermal, but also relieve the decent speed of water lever. It can resolve pollution and discharging of heating water. In the 1970's, reinjection test had been carried out. After 2000, Producing reinjection test was carried out in Xiaotangshan area and succeeded. But there are some key problems fund from geothermal reinjection test, including: problem of restrictions of reinjection ability, problem of reservoir influence after reinjection,problem of reinjection ability decrease and reinjection bloke, unreasonable reinjection process. These have became the technical bottlenecks of geothermal reinjection. The paper chooses Xiaotangshan field as the study area and performs the four key problems of geothermal reinjection by collecting and analyzing the material from work.The paper analyzes restrictions of reinjection ability, including quality of reinjection well, reservoir stress and reinjection resource water etc. and present the thicker reservoir naked in the well is, the lower area press of reservoir is, the lower temperature of reservoir is, The smaller concentration of special components is, the stronger the reinjection ability is. From motoring, it is fund that the reservoir press has decreased because the reinjection and has increased in 2005-2007. The reinjection has made the temperature of reservoir near the well decrease, but has no influence with the reservoir temperature near producing well,and will not form "thermal short-circuiting". With the balance method of water and Dynamic correlation method, the reservoir recharge of nature in Xiaotangshan is predicted, and put forward the conditions of balance of producing and reinjection is that the production is lower than 222m3/a. By checking the well, corrosion and scaling is identified as the main reason. Attempt of injecting the hydrochloric acid, air pressure wash well on the ground and press reinjection is introduced. In addition, the paper analyzes the existing reinjection process, and puts forward the improvement method of well structure design, pressure reinjection, pumping test, temperature monitoring and installing well equipment. In the last, this paper gives some suggestions. The numerical model of reinjection should be constructed as soon as possible, which can provide technical support for government. Construct the theoretical basis of reinjection decrease and block-up and find the science solve method and predicted measure.Perfect the monitoring systems; Strengthen the improve of equipment and management of resource, and make sure of integrity and accuracy of information.