凝析气井异常产能评价

Abnormal Productivity Evaluation of Condensate Gas Well

渤海某凝析气井DST测试过程中,产能测试资料出现异常,通过取样分析,该气藏属特高含凝析油凝析气藏,地露压差仅3.21 MPa,产能测试过程中井底存在反凝析作用,凝析油造成渗流通道堵塞、气相有效渗透率下降,造成气产量降低。文章梳理了目前常用的产能评价方法,应用该井产能测试数据,对比不同方法评价气井产能的差异,评估反凝析伤害对产能的影响。结果表明,考虑气、液两相流动的拟压力法计算无阻流量相较理想状态采用单相法计算的无阻流量下降19.1%,凝析气藏产能评价过程中需充分考虑井下流体流动特征,选择合理的产能评价方法。

During the drill-stem test of a condensate gas well in Bohai oilfield,productivity test data is abnormal,the sampling analysis results show that this reservoir belongs to the condensate gas reservoir with extremely high condensate oil content,and the difference between formation pressure and dew point pressure is only 3.21 MPa,condensate oil exists at the bottom of the well during productivity test,the condensate oil caused the partial seepage channel to be blocked,lead to the gas effective permeability and productivity decreased.This paper summarizes the main productivity evaluation methods,applying productivity data of this test,compared the deviation of different methods for productivity evaluation to assess the effect of retrograde condensation damage,the results show that the two-phase flow pseudo pressure method to calculate QAOF compared with ideal single-phase method dropped 19.1%,the result points out that the condensate gas reservoir productivity evaluation should be fully considered in the downhole flow characteristics,choose the most rational productivity evaluation method.