中深层U型对接井“取热不取水”技术研究

Study on “Heat Withdrawal but Water” U-shaped Butted Wells Technique

以河北工程大学U型对接井闭式换热试验为例,介绍了中深层“取热不取水”技术特点和研究成果。研究表明,大口径长水平距离的U型闭式对接井,换热量大、运行稳定,成功解决了中深层水热型砂岩回灌量小、破坏地下水资源的难题,也解决了单井同轴管模式换热量小、热量衰减快的难题。这种改进的中深层地热采热技术,实现了“取热不取水”,成为地热资源可持续发展探索的新方向,可以在全国范围内推广应用。实际应用时,应做好地热井勘查工作,可通过增加井深、水平段距离及循环水流量、降低注水温度等技术手段提高换热量。

Taking the U-shaped butted wells closed heat transfer test in the Hebei University of Engineering as an example,introduced medium deep“heat withdrawal but water”technological features and studied results.The study has shown that the large diameter long horizontal distance U-shaped closed butted wells have large heat transfer capacity,stable operation and successfully solved hard nut issues of small medium deep hydrothermal sandstone recharge,groundwater resource destruction;meanwhile also solved single well coaxial tube small heat transfer capacity,heat quantity attenuation quick etc.Such improved medium deep geothermal heat withdrawal technology has realized“heat withdrawal but water”,becomes geothermal resources sustainable development probing new orientation,can be widely applied in the whole country.In practices,geothermal well exploration should be done well,through technological means of well depth,horizontal segment distance and circulation water flow increasing,lowering down injection water temperature to improve heat transfer capacity.