| Abstract |
As renewable resource, geothermal energy is very important to the development of the economy of the China. Re-injection of the geothermal fluids after use is effective means for maintaining reservoir pressure which is the key to sustainable utilization of geothermal resources. Re-injection of the geothermal fluid is also important environmentally way preventing surface disposal and pollution of surface waters. In Tianjin area, research regarding re-injection into sandstone reservoirs have been carried out during 1980s to now. Due to chemical scaling in wells and formation, plugging of aquifers and corrosion of casings, the re-injection rates into the sandstone reservoirs decreased dramatically with time. During the re-injection evaluation and research of the drilling techniques, filtering techniques and re-injection regulations. Up to the recent years, we have made a great progress in re-injecting return geothermal water into sandstone reservoirs in several different areas. Five demonstration projects were set up and the re-injection rates acquired great progress, up to 100-120m3/h into a single sandstone re-injection well. In this report, we describes re-injection issues from different perspectives including: reservoir configuration, aquifer characteristics, drilling techniques, filtering techniques as well as re-pumping at the interval of re-injection. We also describe the reinjection experience during the past decades in Tianjin China. |