Geothermal well recharge is a bottleneck that restricts the sustainable development of hydrothermal type geothermal,especially the recharge of sandstone thermal storage is more difficult.In order to reveal the blockage that restrict the process of sandstone thermal storage and reinjection,an experimental study is conducted using a sandstone geothermal well in the"one extraction,one irrigation"model in the Weihe Basin of Guanzhong,Shaanxi Province as an example to explore the four types of blockage mechanisms in the process of sandstone thermal storage and reinjection,and corresponding blockage removal measures are proposed.The results show that the precipitation of carbonates,some aluminosilicates and iron minerals is greatly affected by temperature,and the increase of stratum temperature will accelerate the formation of chemical blockage.With the increase of temperature,suspension blockage and chemical blockage will constitute a synergistic effect.Meanwhile,the Brownian motion velocity of suspended particles also increases with the increase of temperature,which makes the blockage more serious.The main reasons for gas blockage caused by recharge are as follows:it is difficult for large volume bubbles to enter the reservoir,and the bubble diameter is equivalent to the size of the bottom throat.Saprophytic bacteria and iron bacteria are the main microorganisms that cause microbial blockage.Adding scale inhibitors can effectively prevent chemical blockage,adopting multi-stage filtration can slow down physical blockage,adding automatic exhaust devices in the recharge system can prevent gas blockage,and disinfecting the tail water can reduce the risk of microbial blockage.After on-site warm-up season testing,the measures taken to remove blockages are applied to the target geothermal well,resulting ina 100%reinjection rate,reducing the negative impact of possible blockages on reinjection during the reinjection process.
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