含硫高产气井套压预测技术与应用

Prediction of Casing Pressure for High-productivity Gas Wells with Sulfur

气井生产期间,地层高温流体在井筒内流动,导致井筒温度升高,进而导致套压升高、油管臌胀效应增大。通过分析高产气井生产过程中环空压力变化的原因,综合考虑井筒温度变化、密闭空间液体体积变化及油管臌胀效应等因素对气井生产过程中井口套压的影响,建立了井口套压增量耦合运算预测模型,为完井投产方案中合理选择完井液密度、优化设计井下工具参数、井筒安全评估及生产制度的优化设计提供了理论依据。

In production period,high-temperature formation fluid can raise wellbore temperature,further lead to an increase of casing pressure and an enlargement of tubing expansion effect. According to an analysis on the reason why annulus pressure of high-productivity gas wells changes during production,considering the effects of wellbore temperature variation,liquid volume change of enclosed space,and tubing expansion effect on casing pressure, we developed a model to predict coupling operation of casing pressure increment. It provides a theoretic basis for selecting completion-fluid density,optimizing downhole-tool parameter,assessing wellbore safety,and optimizing production system.