摘要
地热资源储量丰富、稳定性好,合理开发利用地热能对缓解能源短缺、实现碳达峰和碳中和目标至关重要.目前,地热可持续取热理论的研究体系尚不完善,准确的地热资源评价是地热可持续发展的关键所在.由于地热在大规模、长时间尺度运行时引起渗流屏障,热储静态预测不能满足热储资源准确评价,动态热储预测是至关重要的.地热井口周围流动复杂,由达西流向非达西流转变,流动具有非线性特性.搭建室内渗流砂箱实验系统,分析不同回灌温度、抽灌流量、补给边界下的渗流传热规律,采集热储动态运行井口压差信号,基于多尺度熵方法分析压差信号的动力学特性,提取大量流动信息,揭示了不同热储补给边界下的动力学特性.结果表明,3种补给边界的多尺度熵均小于1并呈现明显分辨规律,从大到小依次为:定流量补给边界>定水头补给边界>封闭边界,定流量补给边界下的流动更剧烈,回灌过程中受到的扰动更复杂,封闭边界下的熵值波动很小.研究得到的热储预测方法缩短了预测时间、降低了预测成本,能够快速准确地识别采灌过程中的补给模式,为越流型单井抽灌系统的参数选择提供理论指导,对热储动态资源评价具有重要意义,从理论层面上对热储预测提供新的思路,促进地热可持续取热理论的推广.
Geothermal resources are abundant and stable.Therefore,the rational development and utilization of geothermal energy is crucial to alleviating energy shortage and achieving the goals of carbon peaking and carbon neutrality.Presently,the research on sustainable geothermal heat extraction theory is not perfect,and the accurate evaluation of geothermal resources is the key to sustainable geothermal energy development.Due to the seepage barrier caused by the large-scale and long-term operation of geothermal energy plants,static prediction of thermal storage cannot accurately evaluate thermal storage resources.Thus,it is important to realize the dynamic prediction of thermal storage.The flow around the geothermal wellhead is complex,transitioning from Darcy to non-Darcy flow,and has nonlinear characteristics.In this study,we built an indoor-seepage sandbox experimental system to analyze the heat transfer laws of seepage under different recharge temperatures,pumping flow rates,and supply boundaries.Then,we collected data on the dynamic wellhead pressure differential signals of thermal storage operation,analyzed the dynamic characteristics of pressure differential signals based on the multiscale entropy method,and extracted a large amount of flow information,thus revealing the dynamic characteristics under different supply boundaries of thermal storage. The results indicate that the multiscale entropy of three types of supply boundaries is less than 1 and shows a clear resolution pattern. The order from large to small is as follows:constant flow supply boundary> constant head supply boundary>closed boundary. Furthermore,the flow under the constant flow supply boundary is more intense,and the disturbance during the recharge process is more complex. In addition,the fluctuation of en-tropy under the closed boundary is minimal. The results also reveal that the thermal storage prediction method devel-oped through research has shortened prediction time and reduced prediction cost,and it can quickly and accurately identify the supply mode during the extraction and irrigation process. This study provides theoretical guidance for the parameter selection of the overflow-type single-well pumping and irrigation system and is of great significance for the dynamic resource evaluation of heat storage. From a theoretical perspective,this work provides new ideas for thermal storage prediction and promotes sustainable geothermal heat extraction theory.
作者
赵军
周佳琦
宋超凡
李扬
Zhao Jun;Zhou Jiaqi;Song Chaofan;Li Yang(School of Mechanical Engineering,Tianjin University,Tianjin 300350,China;Key Laboratory of Efficient Utilization of Low and Medium Grade Energy of Ministry of Education,Tianjin University,Tianjin 300350,China)
出处
《天津大学学报（自然科学与工程技术版）》
EI
CAS
CSCD
北大核心
2024年第7期695-703,共9页
Journal of Tianjin University：Science and Technology
基金
中国博士后科学基金资助项目(2022M712347).
关键词
地热
多尺度熵
补给边界
热储预测
geothermal
multiscale entropy
supply boundary
thermal storage prediction
