考虑重力对流动影响的地热水平井布井数值模拟

Numerical Simulation of Geothermal Horizontal Well Distribution Considering the Influence of Gravity on Fluid Flow

建立干热岩石热流耦合数学模型,采用经典单裂缝二维岩石基质模型对该文模型进行了验证。以美国沙漠峰EGS项目为例,分别模拟计算并分析了水平井开采地热时的注采井间距、纵向高度差对采热的影响。通过正交实验设计,计算得到了获取最高采热温度时水平井注采井间距与纵向高度差的理论关系,按照该文设计方案开采地热,注采井间距150 m时,采用高度差23.02 m布置水平井网,能有效提高采出温度,使地热开发系统寿命延长8年。该文提出的地热水平井布井方案设计方法,能有效提高水平井采出温度,增加系统开采寿命,对地热资源的开发具有很好的实践指导价值。

The mathematical model of TH coupling for hot dry rock was established, and the model was verified by the classical two-dimensional rock matrix model with single fracture. Taking the EGS project in the desert peak of the United States as an example, the effect of injection-production well spacing and vertical height difference during the geothermal extraction in horizontal wells was simulated and analyzed. By orthogonal experimental, the theoretical relationship between the injection-production well spacing and the vertical height difference was obtained. The results indicated that,when the injection-production well spacing was 150 m and the vertical height difference was 23.02 m, the production temperature was effectively improved, and the life of geothermal development system was extended by 8 years. The design method of geothermal horizontal wells can effectively improve the production temperature and increase the production life of the system,it has a good practical value for geothermal energy development.