西藏羊易EGS开发储层温度场与开采寿命影响因素数值模拟研究

西藏羊易地区具有丰富的地热能，单井开发潜力接近10 MW，对其深部热储进行EGS开采，可缓解西部能源紧缺问题。本文建立二维理想EGS开发模型，探讨深层地热开采过程中开采流量、注采方式、注入温度等参数对热储温度场分布及开采寿命的影响。基于羊易温度信息设计了12个数值模型，对比研究发现，开采流量对EGS开采的影响较大，为保证开采50年内的商业利用价值，最大开采流量应控制在0.028 kg/s以下；考虑到钻井成本，注采方式的选择以高注高采和中注高采为最佳；注入温度对热储开采影响较小，可选择40℃ ~ 80℃之间任意温度的地热尾水进行回灌，实现地热资源梯级利用。

Numerical Simulation Study of the Parameters Effect on Temperature Distribution and Mining Life during EGS Exploitation,Yangyi of Tibet

There is a rich geothermal energy in Yangyi area of Tibet and the potential energy of single well can be up to 10 MW. Utilization of Enhanced Geothermal System (EGS) technology in the exploitation of deep geothermal energy can alleviate the western energy shortage problem. An idealized 2D EGS numerical model was built to discuss the influence of production flow, injection-production pattern, injection temperature and other parameters on reservoir temperature distribution and mining life during the process of deep geothermal exploitation. 12 cases were designed based on the temperature information of Yangyi and the conclusions are as follows: production flow has a great influence on EGS exploitation, maximum production flow should be controlled below 0.028 kg/s to ensure commercial exploitation value for 50 years; considering the drilling cost, it is better to take high-injection-high-production and middle-injection-high-production pattern; the influence of injection temperature on the reservoir is small, any tail water between 40oC ~ 80oC can be reinjection into EGS reservoir to achieve the utilization of geothermal gradient.