地热深井生产过程的井筒传热数值模拟  

Numerical simulation of wellbore heat transfer in the production process of geothermal deep well

作　　者：单丹丹[1,2] 闫铁 李玮[1,2] 薛云龙[3] 张弦[1,2] 罗鹏飞 SHAN DanDan;YAN Tie;LI Wei;XUE YunLong;ZHANG Xian;LUO PengFei(College of Petroleum Engineering,Northeast Petroleum University,Daqing 163318,China;Key Laboratory of Enhanced Oil Recovery(Northeast Petroleum University),Ministry of Education,Daqing 163318,China;Exploration and Development Research Institute,Changqing Oilfield,Xi’an 710016,China;Exploration and Development Research Institute,Liaohe Oilfield,Panjin 124010,China)

机构地区：[1]东北石油大学石油工程学院,大庆163318 [2]提高油气采收率教育部重点实验室(东北石油大学),大庆163318 [3]长庆油田勘探开发研究院,西安710016 [4]辽河油田勘探开发研究院,盘锦124010

出　　处：《地球物理学进展》2021年第5期1891-1899,共9页Progress in Geophysics

基　　金：国家自然科学基金面上项目“基于岩石共振的旋冲钻井动力学系统的破岩机理研究”(51774093);东北石油大学引导性创新基金项目“多尺度下热储与井筒多场耦合模拟研究”(2018YDL-10)联合资助。

摘　　要：从地热储层中提取热流体的过程中,在井筒流体与周围地层之间存在着热量交换,使得热流温度发生着变化,为探究流体在生产井中的热量损失过程,本文的目的是开发一种可靠的数值模型用以说明地热井在生产过程中的流动与换热问题,在此选取COMSOL Multiphysics建立了仿真模型,并对模拟结果进行了解析验证.井筒热量损失的表征要素除了温度以外,热损失功率也起着至关重要的作用,为了全面评价地热生产井的热能损失,故对井口水温及热损失功率两项评价指标进行研究,分析得出水的操作参数及环空热导率变化对井筒热损失的影响.研究结果表明:(1)数值模拟中应用TD代数表达式的连续形式与解析模型中应用Ramey定义的f(t)不连续函数表达式进行热流温度的求解时,对于较长的生产时间,数值解与解析解吻合良好.(2)井底水温的线性变化也将带来井口水温和井筒热损失功率的线性变化,井口水温和井筒热损失功率随井底水温的变化直线斜率随时间的增加略有减小,纵截距也略有减小,说明时间越长,井口温度升高的越慢,井筒热损失功率增大的越小,系统越趋于稳定状态.(3)增量为10 kg/s的采出流量与增量为10℃的井底水温相比,对井口水温的升高及热损失功率的减小影响程度均相应减弱,最终也将趋于稳定状态.(4)环空热导率对井口水温和井筒热损失功率的影响呈现相反的效应,即环空热导率增大井口水温降低,井筒热损失功率增大.结论认为,综合考虑热流温度及井筒热损失功率两项指标对于高效地热能开采,提高热能利用率等方面具有重要意义,并可全面评价井筒的热量损失大小,为地热能开发提供可靠理论依据.In the process of extracting thermal fluid from the geothermal reservoir, there is heat transfer between the wellbore fluid and the surrounding formation, which causes the heat flow temperature to change. In order to probe into the heat loss process of fluids in the production wells, the purpose of this paper is to develop a reliable numerical model to illustrate the flow and heat exchange problems of geothermal wells during production. Here, COMSOL Multiphysics is selected to establish a simulation model, and the simulation results were analyzed and verified. In addition to temperature, the heat loss power also plays an important role in the characterization of wellbore heat loss. In order to comprehensively evaluate the thermal energy loss of geothermal production wells, the two evaluation indicators of wellhead water temperature and thermal loss power were studied, and the influence of water operating parameters and annulus thermal conductivity changes on wellbore heat loss was analyzed. The research results show that:(1)When the continuous form of T;algebraic expression used in numerical simulation and the discontinuous function expression of f(t) defined by Ramey used in the analytical model to solve the heat flow temperature, for long production time, the numerical solution and the analytical solution agrees well.(2)The linear change of the wellhole water temperature will also bring about a linear change of the wellhead water temperature and the wellbore thermal loss power. It decreases slightly with time that the linear slope and longitudinal intercept of wellhead water temperature and also wellbore thermal loss power with wellhole water temperature. It means that the longer the time, the slower the temperature rise at the wellhead, the smaller the increase in the wellbore thermal loss power, and the more the system tends to a stable state.(3)Compared with the wellhole water temperature in increments of 10 ℃, the produced rate in increments of 10 kg/s has a correspondingly weaker effect on the increase i

关 键 词：热流温度 生产井 COMSOL Multiphysics 井口水温 热损失功率 井底水温 采出流量 环空热导率 

分 类 号：P314[天文地球—固体地球物理学]