单裂隙热储热流耦合数值模拟分析

Numerical Simulation and Analysis of Thermal-Hydraulic Coupling in A Single-Fracture Thermal Reservoir

为探究影响增强型地热系统(EnhancedGeothermalSystem,EGS)高效运行的各项因素,以单裂隙热储为研究对象,基于裂隙岩体热流耦合数学模型,对单裂隙下EGS热流耦合进行数值模拟,利用有限元软件COMSOL实现对裂隙岩体温度场与渗流场的耦合求解,分析热储层内渗流、温度的分布规律,以及基岩渗透率、热传导系数等岩体热物性参数变化;裂隙宽度、裂隙流流速、开采时间等基本计算参数变化对裂隙岩体渗流与传热的影响,得出在一定范围内基岩渗透率与热传导系数增大会使系统运行寿命提高,裂隙宽度及裂隙流流速对热开采效率的影响呈现正相关性。

In order to explore the factors affecting the efficient operation of enhanced geothermal system(Enhanced Geothermal System,EGS),taking a single-fracture thermal reservoir as the research object,based on the mathematical model of thermal-hydraulic coupling of fracture rock mass,the numerical simulation of EGS thermal-hydraulic coupling under a single-fracture was carried out.The coupling solution of temperature field and seepage field of fracture rock mass was realized by using finite element software COMSOL,and the distribution of seepage and temperature in thermal reservoir was analyzed,as well as the variation of thermal physical parameters of rock mass,such as permeability and heat conduction coefficient of bedrock.The influence of basic calculation parameters such as fracture width,fracture flow velocity and mining time on seepage and heat transfer of fracture rock mass was investigated.The results showed that the increase of bedrock permeability and heat conduction coefficient in a certain range will increase the operating life of the system,and the influence of fracture width and fracture flow velocity on thermal mining efficiency was positively correlated.