The multi-horizontal section hot dry rock (HDR) heat extraction system is proposed for efficient deep geothermal resources mining in this study. The thermal-hydraulic numerical model of the multi-horizontal section geothermal exploitation system is set up, the space-time evolution of temperature field is analyzed. The sensitivity factors including completion schemes, horizontal well diameter, quantity of horizontal sections and spacing of horizontal sections are investigated. The simulation results show that the production temperature and heating power of the multi-horizontal HDR production system decrease with the development of mining, and the decreasing speed gradually slows down. The open hole completion can be preferred when the formation conditions permit. The variation of horizontal well diameter has little effect on heat production when other conditions remain unchanged. The quantity of horizontal sections to be 3 or 4 for better heat extraction performance under the spacing of horizontal section remains 300m and the spacing of the horizontal section to be 150m is recommended within the scoped of this study. The results of this study can provide guidance for HDR mining research.

中文翻译：

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多水平U型井热采效果分析


本研究提出了多水平段干热岩（HDR）排热系统，用于高效深层地热资源开采。建立了多水平断面地热开发系统的热工水力数值模型，分析了温度场的时空演化。考察了完井方案、水平井直径、水平段数量、水平段间距等敏感因素。仿真结果表明，多水平HDR生产系统的生产温度和加热功率随着挖矿的发展而降低，且降低速度逐渐减慢。当地层条件允许时，可优先采用裸眼完井。在其他条件不变的情况下，水平井直径的变化对产热量影响不大。在水平段间距保持300m的情况下，为了获得更好的排热性能，水平段数量为3或4个，在本研究范围内建议水平段间距为150m。本研究结果可为HDR挖掘研究提供指导。