中深层U型地热井取热影响因素数值模拟研究

Numerical Simulation of Influencing Factors of Heat Extraction in Middle-deep U-shaped Geothermal Well

在“采热不采水”的背景下,U型地热井是实现中深层地热高效开采的一种重要手段.结合河南豫东地区地质与储层资料,以建设3000 m深U型地热井为对象,通过数值模拟研究了20年运行情景下运行参数对取热和出口温度的影响.结果表明,在满足该区用户负荷情况下,合理的注入水温度为9℃、流量为120 m^(3)/h;若要求较高的出口温度,建议采用导热油作为工作介质;在长期运行情况下,工作介质类型和流量影响水平取热段的温度扰动突破时间,出口温度在该时间之前基本保持稳定;建议从负荷要求和长期运行角度出发,优化确定合理的运行参数.

Under the background of“heat mining without water mining”,U-shaped geothermal well is an important means to realize efficient exploitation of medium-deep geotherm.Based on the geological and reservoir data of eastern Henan Province,the influence of operating parameters on heat extraction and outlet temperature under 20 years of operation scenario is studied by numerical simulation with a 3000 m deep U-shaped geothermal well as the object.The results show that the reasonable water injection temperature is 9℃and the flow rate is 120 m^(3)/h when the user load in this area is satisfied.If higher outlet temperature is required,heat conduction oil is recommended as the working medium.In long-term operation,the type of working medium and flow rate affect the breakthrough time of temperature disturbance in the horizontal heat extraction section,and the outlet temperature basically stays stable before this time.It is suggested to optimize and determine reasonable operation parameters from the perspective of load requirements and long-term operation.