【摘要】 基于CFD理论并应用CFD软件建立了简化的全井段天然气井井下节流工艺的物理模型。考虑到地温梯度对井筒温度的作用,编写了关于温度梯度的UDF程序,对井下全井段流场与温度场进行了数值模拟。得到了井下气体温度、压强、流速关于井深的分布曲线并对节流处的参数变化进行分析。通过模拟发现,节流前后的温降较大,温度在节流口出口附近存在最小值。地热对节流后天然气起到了加温作用;模拟结果证实了井下节流工艺具有保温的特点,为合理确定节流嘴下入深度,使节流后天然气温度高于节流后压力下水合物生成温度,从而为预防水合物生成提供了一定的理论依据。更多还原

【Abstract】 Based on the CFD theory,a simplified physical model of the throttling technique of natural gas in the subsurface gas well is established with the CFD software.Considering the influence of the temperature gradient on the wellbore temperature,the present author writes a UDF program concerning temperature gradient to simulate the temperature field and flow field of the whole gas well in the subsurface gas well.As a result,the gas temperature,pressure,velocity,and the distribution curve of the well depth are achieved.The parameter variation of the throttling zone is also analyzed.The results show that the temperature drops greatly before and after throttling,and the minimum value of temperature is at the outlet of throttling.Geothermal plays a part in the throttling gas,which can heat the gas after throttling.The simulation results complies with the engineering practice,which proves that the throttling process has the characteristics of thermal insulation.Therefore,it provides a theoretical foundation for ascertaining the reasonable down-into depth of the throttling mouth,making the after-throttling temperature higher than the generated temperature under the pressure of natural gas hydrates after throttling,and preventing the generation of hydrate.更多还原