井下节流气井井底压力计算方法应用研究

Application of Bottom Hole Pressure Calculation Method for Gas Well with Downhole Throttling

准确预测井下节流气井井底压力,是预测气井产能、诊断井筒积液、制定合理排水采气制度的重要基础。通过引入滑脱因子K表征气液两相间滑脱效应,建立了气液两相嘴流压降模型,并将气液两相嘴流压降模型与优选出的No-Slip/H-B管流压降模型进行全井筒耦合,形成井下节流气井全井筒压力预测新方法,并开发出计算软件,可实时定量预测气井全井筒积液高度和井底流压值。评价结果表明,新方法预测井下节流气井井筒流压值与实测值较接近,平均误差为2.87%,满足工程计算精度要求,可以有效指导东胜气田气井积液诊断和动态排水采气分析工作。

Accurate prediction of bottom hole pressure in downhole throttle gas wells is an important basis for predicting gas well productivity,diagnosing liquid loading and establishing a reasonable drainage gas recovery system.In this paper,slippage factor K is introduced to characterize the slippage effect between gas and liquid,a pressure drop model of gas-liquid two-phase nozzle flow is established,and the pressure drop model of gas-liquid two-phase nozzle flow is coupled with the optimized No-Slip/H-B pipe flow pressure drop model to form a new method which is used to predict the whole wellbore pressure of downhole throttling gas wells.In addition,a calculation software is developed to predict the whole wellbore liquid loading height and bottom hole pressure of gas wells in real time.The evaluation result shows that the prediction value of wellbore flow pressure is close to the measured value,with average error of 2.87%.It shows that this new method meets the accuracy requirements of engineering calculation,and can effectively guide the diagnosis of liquid loading and dynamic drainage gas production analysis in Dongsheng Gas Field.