海上油井用井下高处理流量旋流分离器的仿真分析

Numerical Analysis of High Flow Rate Cyclone Separator for Offshore Oil Well

根据对海上油井用井下高处理流量(500m3/d)旋流器进行仿真分析,介绍了油水分离用旋流器的CFD数值模拟及结果分析方法。针对海上油井高产液量的特点,从能耗和效率两方面评价了高处理流量旋流器的分离性能。利用仿真结果,分析旋流器流场速度、压力、油滴切应力、湍动能等随流量的变化规律,通过分析可知,当流量增加时,切向速度及径向压力梯度增大,在一定程度上使得分离效率增加;涡流场中油滴时均切应力随流量变化较小,但由湍流引起的瞬时切应力受流量影响较大,这是加剧油滴破碎的主要原因;流量相同时,多级小名义直径旋流器并联的分离性能要优于单级旋流器,但单级旋流器结构紧凑,便于布置流道,更适合井下应用。

The numerical simulation and analysis of hydrocyclone for high flow rate oil/water separation are conducted. The simulation results of the high flow rate( 500 m3/d) hydrocyclone are analyzed. The separation performance of the high flow rate cyclone was evaluated from the aspects of energy consumption and efficiency in view of the characteristics of high oil production in offshore oil wells. The results show that the tangential velocity and the radial pressure gradient of the hydrocyclone increase with the increase of the flow rate, and the velocity and pressure of the hydrocyclone, the shear stress of the oil droplet and the turbulent kinetic energy vary with the flow rate. The shear stress of the oil droplet in the eddy current field is smaller than that of the flow, but the instantaneous shear stress caused by the turbulence is greatly affected by the flow rate, which is the main factor that aggravates the breakage of small oil droplet. The separation performance of the multi-stage small nominal diameter cyclone is better than that of the single-stage cyclone, but the single-stage cyclone is compact and easy to arrange the runner, which is more suitable for downhole application.