基于热流固耦合的单井增强地热系统数值模拟
Numerical simulation of a single-well enhanced geothermal system based on thermal-hydraulic-mechanical coupling
郭志鹏 1卜宪标 2赵源 3李华山 2王令宝2
作者信息
- 1. 中国科学技术大学 工程科学学院,安徽 合肥 230026;中国科学院 广州能源研究所,广东 广州 510640
- 2. 中国科学院 广州能源研究所,广东 广州 510640
- 3. 中国电建集团华东勘测设计研究院有限公司,浙江 杭州 311122
- 折叠
摘要
为提高深井换热器的取热效率,借鉴干热岩的开发思路,本文提出了一种单井增强地热系统.对单井套管底部岩体进行小范围压裂改造,将单井套管由封闭式系统改为开式系统来提高单井系统的取热性能.建立了热-流-固耦合的三维非稳态数值模型,研究了单井增强地热系统的系统性能表现和各关键参数的影响.结果表明:与传统深井换热器相比,单井增强地热系统的取热性能有较大提升,相同注入工况下,生产温度和取热功率分别提高了 62.21℃和 2 612.99 kW;从地热工程周期和优化角度出发,单井增强地热系统流量控制在 10 kg/s较为适宜,过小的单井增强地热系统流量导致取热效率较低,过大使得系统运行寿命较短;增大井筒封隔间距、减小内管导热系数是提高系统取热性能的有效方法.本文研究可为单井增强地热系统的理论分析和实际应用提供参考.
Abstract
To improve the heat extraction efficiency of deep well heat exchangers,a single-well enhanced geother-mal system(SEGS)was proposed using the development idea of hot dry rock for reference.The rock mass at the bottom of a single-well casing was reformed by small-scale fracturing;the single-well casing was changed from a closed system to an open system to improve the heat extraction performance of a single-well system.A thermal-hy-draulic-mechanical coupling three-dimensional unsteady-state numerical model was established to study the system performance of SEGS and the influence of various key parameters.Results show that compared with the traditional deep well heat exchanger,SEGS has a greatly improved heat collection performance.Under the same injection con-dition,the production temperature and heat collection power are increased by 62.21℃and 2 612.99 kW,respec-tively.In terms of a geothermal engineering cycle and optimization,it is more appropriate to control the SEGS flow at 10 kg/s.A small flow of SEGS decreases heat extraction efficiency,and a large flow shortens service life.In-creasing the wellbore spacing and reducing the thermal conductivity of the inner pipe effectively improves the heat transfer performance of the system.Herein,we provide a reference for the theoretical analysis and practical appli-cation of SEGS.
关键词
地热能/深井换热器/增强型地热系统/单井/多孔介质/压裂储层/渗透率/热流固耦合Key words
geothermal energy/deep borehole heat exchanger/enhanced geothermal system/single well/porous media/fractured reservoir/permeability/thermal-hydraulic-mechanical coupling引用本文复制引用
出版年
2024
国家科技期刊平台
NSTL
万方数据