井下双级串联式水力旋流器数值模拟与实验

Numerical simulation and experiment of downhole two-stage tandem hydrocyclone

利用Euler-Euler法与大涡模拟相结合对井下双级串联式水力旋流器的分流特性和分离特性进行研究,并与实际实验结果相对比。结果表明:入口流量由20 m^3/d增加到60m^3/d时,总分流比的范围逐渐变大,且第一、二级水力旋流器的溢流口流量之比与总分流比的变化关系是函数关系;在一定范围内,底流含油质量浓度随着入口流量的增大先减小后增大,随着总分流比的增大先减小后增大;入口流量为25~50 m^3/d且总分流比为0.28~0.75时,底流含油质量分数不大于200×10^(-6);数值模拟预报的分流特性与实验结果一致,预报的分离特性与实验结果存在一定差异。该模拟解决了文献[23]提出的监测模型难以用于配带双级串联式水力旋流器井下油水分离系统工况诊断的问题,并给出了井下工况调节时总分流比的推荐范围,从而可以为现场应用提供一定指导。

A combination of the Euler-Euler approach and the large eddy simulation model is adopted for numerical simulation of split ratio and separation characteristics of downhole two-stage tandem hydrocyclone.The predictions are validated by comparison with experimental results.As inlet flow rate increases from 20 to 60 m^3/d,the range of total split ratio is broadened gradually,and the changing relation between overflow ratio of the first and second hydrocyclones and total can be defined as a deterministic function.In a certain range,the oil mass concentration in underflow undergoes decreases followed by increases with the increasing inlet flow rate and total split ratio.At inlet flow rate of 25-50 m^3/d and total split ratio of 0.28-0.75,the oil mass concentration of underflow is not greater than 200 × 10^-6.The split characteristics predicted by numerical simulation are consistent with experimental data,while the predicted separation characteristics have certain differences.This study solves the difficulty in applying monitoring model for diagnosis of the operating conditions in the downhole oil-water separation system with two-stage tandem hydrocyclone,as presented in Reference 23.The recommended range of the total split ratio for the adjustment of downhole operating conditions is given,which provides some guidances for field applications.