摘要
提取地下热储层内热水为建筑进行供暖是提取中深层地热能的重要技术手段之一。其中,将地热水进行回灌有助于维持地热储层压力,但可能产生热贯通等问题。利用FEFLOW软件建立了三维抽灌井水-热耦合模型,并对影响抽灌井系统取热性能的因素进行了模拟研究。结果表明,在该地热含水热储层条件下,抽灌井间距为300 m时,系统运行20年(7300 d)后,抽水井处不会产生热贯通效应。抽灌流量对系统运行性能有着直接的影响,抽灌流量越大,抽水井温度下降越早,系统末期抽水井温度越低,但仍能提供较高的产热量,较大流量与较小流量工况下系统运行末期温差约为3.87℃,取热量差可达2252471 W。抽水井温度随回灌温度的增加而增加,但含水层取热量逐渐降低。较大回灌温度与较小回灌温度工况下系统运行末期温差约为1.92℃,取热量差可达3150440 W。天然水流方向一定时,在不同水力坡度条件下,水力坡度对抽灌井系统性能的影响逐渐增加。当水力坡度为0.01时,位于地下水渗流下游方向的抽水井产生热贯通效应时间比位于上游时早1732 d,含水层取热量减少634270 W。因此,热储层中地下水渗流方向与抽灌井连线方向相同(即抽水井位于上游)时,系统取热性能较优。
Extracting warm water from geothermal reservoir to heat buildings is one of the important technical means for extracting middle-deep geothermal energy.Among them,reinjection of geothermal water helps to maintain the pressure of the geothermal reservoir,but may cause problems such as thermal breakthrough.A three-dimensional hydro-thermal coupling model of geothermal wells system was conducted by using software FEFLOW,and the factors affecting the heat extraction performance of the system were simulated.The results show that,under the conditions of this paper,when the well spacing is 300 m,after the system has operated for 20 years(7300 d),there will be no thermal breakthrough effect at the pumping wells.The production rate has a direct impact on the performance of the system.The larger the production rate is,the earlier the production temperature decreases,and the lower the production temperature at the end of the system,but it can still provide higher heat extraction.Under working conditions,the temperature difference at the end of the system operation is about 3.87℃,and the difference in heat extraction from the thermal reservoir can reach 2252471 W.The production temperature increases with the increase of the injection temperature,but the heat extraction of the thermal reservoir decreases gradually.The temperature difference between the larger injection temperature and the lower injection temperature at the end of system operation is about 1.92℃,and the difference in heat extraction can reach 3150440 W.When the direction of groundwater flow is constant,under different hydraulic gradient conditions,the influence of hydraulic gradient on the performance of the system gradually increases.When the hydraulic gradient is 0.01,the production well located in the downstream direction of groundwater flow will produce a thermal breakthrough effect 1732 d earlier than when located upstream,and the heat extraction from the aquifer is reduced by 634270 W.Therefore,when the groundwater flow direction in the thermal reserv
作者
康文凯
杨向儒
阎若萍
刘峰
KANG Wen-kai;YANG Xiang-ru;YAN Ruo-ping;LIU Feng(School of Energy and Environment Engineering,Hebei University of Technology,Tianjin 300401,China;Institute of Hydrogeology and Environment Geology,Chinese Academy of GeologicalSciences,Shijiazhuang 050061,China;Technology Innovation Center of Geothermal and Hot Dry RockExploration and Development,Ministry of Natural Resources,Shijiazhuang 050061,China)
出处
《建筑节能（中英文）》
CAS
2022年第1期107-113,共7页
Building Energy Efficiency
基金
中国地质调查局项目(DD20190128,DD20190555)。
关键词
抽灌井系统
回灌
井间距
抽水温度
doublet well system
injection
well spacing
production temperature
