分离腔结构对井下旋流器分离性能的影响研究

为得到水力旋流器的最佳分离效果,采用数值模拟方法,通过改变入口进液速度和分流比,对导锥式旋流器和倒锥式旋流器的流场特性及分离性能进行了对比分析,获得了相同操作参数下两种结构的速度场、浓度场(溢流口油相体积分数)及压力场分布特性。分析结果表明:当入口进液速度为0.3~1.5 m/s时,导锥式旋流器具有较高的分离性能,此时压降比不高于1.5,溢流口油相集中,随入口进液速度增大分离效率由97.5%上升到99.2%;当进液速度为1.5~3.5 m/s时,倒锥式旋流器分离高效且稳定,此时压降比不高于1.5,溢流口油相集中,随入口进液速度增大分离效率由98.0%上升到99.7%;倒锥式旋流器的零轴向速度包络面有扩充作用,且倒锥结构可减缓流场中混合液速度;导锥式旋流器最佳分流比为20%,倒锥式旋流器最佳分流比为30%。研究结果可为同井注采工艺中油水分离器选型提供参考。

Influence of Separation Chamber Structure on Separation Performance of Downhole Hydrocyclone

To obtain the best separation performance of hydrocyclone,the flow field characteristics and separation performance of the starting-taper hydrocyclone and back-taper hydrocyclone are analyzed using numerical simulation method by changing the inlet velocity and the split ratio. The velocity field,concentration field and pressure field distribution of the two hydrocyclone structures under the same operating parameters are obtained. Under the inlet velocity of 0. 3 ~ 1. 5 m/s,the starting-taper hydrocyclone has a better separation performance. The pressure drop ratio is not higher than 1. 5,and the oil phase of the overflow port is concentrated. The separation efficiency increases from 97. 5% to 99. 2% with the increase of the inlet velocity from 0. 3 m/s to 1. 5 m/s. When the inlet velocity is 1. 5 ~ 3. 5 m/s,the back-taper hydrocyclone separation efficiency is better and stable. The pressure drop ratio is not higher than 1. 5,and the oil phase of the overflow port is concentrated. The separation efficiency increases from 98. 0% to 99. 7% with the inlet velocity increased from 1. 5 m/s to 3. 5 m/s. The back-taper structure can slow down the velocity of the mixed liquid in the flow field. The optimal split ratio of the starting-taper hydrocyclone and the back-taper hydrocyclone is 20% and 30%,respectively.