高黏度流体垂直井筒携砂临界流速实验与计算

生产实践证明适度出砂开采稠油能够有效增加油井产能，高黏度流体在井筒内携砂临界流速的确定是稠油适度出砂生产设计的关键参数之一。结合调研文献资料，考虑砂粒形状、砂粒浓度和器壁干涉等因素影响后，给出了适用于高黏流体计算砂粒沉降速度的砂粒器壁干涉沉降速度经验公式，采用垂直井筒携砂模拟实验装置进行实验，静态沉降实验得出了砂粒形状校正系数，高黏流体携砂临界流速实验测得实际携砂临界流速，拟合砂粒器壁干涉沉降速度和携砂临界流速，得出高黏流体携带不同粒径砂粒的临界流速计算式。结果表明，砂粒器壁干涉沉降速度与携砂临界流速基本上呈线性关系；黏度越大，砂粒器壁干涉沉降速度与其携砂临界流速值越接近。

Experiment and calculation of critical sand-carrying velocity for high-viscosity fluid in vertical wellbore

Productive practice proves that the recovery of heavy oil using moderate sand production technology can effectively increase oil well productivity. The critical sand-carrying velocity for high-viscosity fluid in vertical wellbore is one of the key factors regarding the moderate sand production design for heavy oil. Referring to research documents and considering the influences of some factors such as sand particle shape, concentration and container wall interference, an empirical equation is proposed for the interference settlement velocity of sand-particle container wall, which is applicable to calculate the sedimentation velocity of sand particles in high-viscosity fluid. By the use of vertical-wellbore sand-carrying simulation experiment device, the sand particle shape correction coefficient is obtained by static settlement experiment, and the actual sand-carrying critical velocity is acquired by critical sand-carrying velocity experiment for high-viscosity fluid. Further, by fitting the interference settlement velocity of sand-particle container wall and the critical sand-carrying velocity, a formula is acquired for calculating the critical velocity of high-viscosity fluid carrying sand particles with different sizes. The results show that the interference velocity of sand-particle container wall has a bacically liner relationship with the critical sand-carrying velocity. The greater the viscosity is, the closer to critical sand-carrying velocity value the interference settlement velocity of sand-particle container wall will be.