复合射孔气液作用后气体上移运动规律实验研究

Experimental Study on Gas Movement Mechanism in Wellbore after Compound Perforation

利用复合射孔压井液运动相似模拟实验装置,研究了复合射孔过程中气液作用结束后气柱在压井液中的上移运动规律。观测了复合射孔过程中气液冲击作用结束后气体在模拟井筒的上移运动过程,考察了不同气体压力、不同气体体积作用下的气液作用结束后气体在液柱中的上移运动状态及变化规律。分析了实测的气体上移运动速度变化曲线。作用的气体压力越大、作用的气体的量越多,气泡的上移速度就越快。此外井筒内液柱的波动对气体的上移运动速度有增大作用。通过与Taylor模型的计算结果对比,结合油田实际状况,得出目前大部分油田现场复合射孔施工后,井底的高能气体均是以Taylor泡的形式在压井液中向上运动。实验结果对深入研究复合射孔气液作用结束后气体上移运动机理有一定的指导意义。

The similar control fluid movement stimulated experimental device is used to study the explosive gas movement mechanism in the wellbore after compound perforation. The flow phenomenon of gas movement is observed in the stimulated wellbore. The gas movement state and gas movement rule at the different initial gas pressures and different initial gas volumes are analyzed. The velocity curve of gas movement that was measured is analyzed. The results indicate that, the higher initial gas pressure, the more initial gas volume, and the faster gas movement, after initial gas-liquid interaction. Moreover, the function of liquid column is benefit to increase the velocity of gas movement. Through contrasting the results with Taylor formation and experimental results, and also considering the compound perforation in the oilfield, it is concluded that the gas movement in the wellbore is similar to the Taylor bubble after compound perforation in the most part of compound perforations in the oilfield. The experimental results have directive significance in studying gas movement mechanism in the wellbore after compound perforation.