Earth Science Frontiers ›› 2024, Vol. 31 ›› Issue (6): 196-203.DOI: 10.13745/j.esf.sf.2024.7.18

Previous Articles     Next Articles

Insights into the root causes of difficulties in reinjection in sandstone geothermal reservoir and countermeasures

ZHAO Kan1,2(), SHEN Jian1,2, CAI Yun1,2,*(), ZHAO Sumin2   

  1. 1. Tianjin Institute of Geothermal Exploration and Development-Design, Tianjin 300250, China
    2. Observation and Research Station of Tianjin Low-Medium Temperature Geothermal Resources, Ministry of Natural Resources, Tianjin 300250, China
  • Received:2024-05-31 Revised:2024-08-29 Online:2024-11-25 Published:2024-11-25

Abstract:

Abundant sandstone geothermal reservoirs with large reservoir thickness are widely distributed in China, and they are the main geothermal resource for heating in the country’s northern and western regions. However, sandstone reserviors are difficult to recharge due to the small rechargeable volume, high recharge decay, and difficulty to develop on a large scale. Previous researches mainly focused on the common causes, such as drilling fluid contamination and physical/chemical clogging. Based on comprehensive review of oilfield water injection technology and results from sandstone core experiments and field reinjection tests, combined with analysis and summary of production reinjection data as well as results from sandstone reservoirs in Tianjin, Shandong and Shaanxi, we considered that the root causes of small recharge volume and recharge decay were small pore diameter, highly tortuous pore channel, and high frictional resistance (pressure dissipation) along the seepage channel of reinjection fluids. The countermeasures identified included accurate characterization of sandstone reservoirs, enlargement of reinjection wells, reduction of reinjection flow rate in the near-well area, and inhibition of speed-sensitive hydrological interactions.

Key words: sandstone geothermal reservoirs, reinjection, clogging, Guantao Formation, seepage channel, pressure gradient

CLC Number: