Practical Experience and Research in the Reinjection Into Sandstone Reservoirs in Tianjin, China

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.