地热井倾斜度对热采效率影响的三维数值分析

Three-dimensional numerical analysis of the influence of geothermal well inclination on thermal recovery efficiency

由于地热开采场地地质条件的复杂性,钻井过程中可能出现倾斜井.地热井倾斜度对热采效率影响的相关研究非常少见.为研究地热井倾斜度对热采效率的影响,基于地热井概念模型,应用离散元程序分析不同地热井倾斜度下岩体温度场、地热井温度场与地热井出口水温的演变特征.结果表明:(1)随着地热井倾斜度增大,地热井长度逐渐缩短,模型最低温度上升幅度逐渐减小,岩体和地热井的热流密度变小,岩体和地热井的导热速率变慢.(2)模型达到稳态所需要的时间随地热井倾斜度增大而缩短,地热井出口水温随地热井倾斜度增大而升高.研究结果可为实际热采工程中地热井倾斜度对热采效率的影响提供一定的指导.

Due to the complexity of geological conditions of geothermal exploitation site,inclined drilling may occur during drilling.The research on the influence of geothermal well inclination on thermal recovery efficiency of rock mass is very rare.In order to study the influence of geothermal well inclination on thermal recovery efficiency,based on the conceptual model of geothermal well inclination,the evolution characteristics of rock mass temperature field,geothermal well temperature field and geothermal well outlet water temperature under varying geothermal well inclination were calculated and analyzed by discrete element program.The results show that:(1)With the increase of geothermal well inclination,the length of geothermal well is gradually shortened,the minimum temperature rise of model is gradually reduced,the heat flux density of rock mass and geothermal well becomes smaller,and the heat conduction rate of rock mass and geothermal well becomes slower.(2)The time required for the model to reach steady state is shortened with the increase of geothermal well inclination,and the outlet water temperature of geothermal well tend to be elevated with the increase of geothermal well inclination.The results can provide the important guiding significance for the influence law of geothermal well inclination on thermal recovery efficiency in practical thermal recovery engineering.