螺杆式连续油管水力振荡器轴向力及其影响因素分析

Analysis of Axial Force and Its Influencing Factors of Screw Type Coiled Tubing Hydraulic Oscillator

随着长水平段油气井的增多,外径小、柔性大的连续油管在井下越来越易发生螺旋屈曲锁死以至无法继续下入。连续油管水力振荡器能够有效降摩减阻,延迟螺旋屈曲锁死,增加连续油管的下入深度,因而得到广泛应用。根据螺杆式连续油管水力振荡器工作过程中的运动和受力分析,得出其轴向力计算公式。采用灰色关联度法分析各影响因素对连续油管水力振荡器轴向力的影响程度,得出流量、流体密度以及转子偏心距对其轴向力影响最大。实例计算表明:连续油管水力振荡器最大轴向力随流量、流体密度以及转子偏心距的增加而变大;连续油管水力振荡器轴向力变化频率与流体密度无关,随流量增加而变大,随转子偏心距增加而减小。

With the increase of oil and gas wells with long horizontal section,coiled tubing with small outer diameter and large flexibility is more and more prone to spiral buckling locking in the downhole,so that it can not continue to run.Coiled tubing hydraulic oscillator can effectively reduce friction and drag,delay spiral buckling locking,and increase the running depth of coiled tubing,so it is widely used.According to the motion and force analysis of screw coiled tubing hydraulic oscillator in the working process,the axial force calculation formula was obtained.The grey correlation method was used to analyze the influence degree of various influencing factors on the axial force of coiled tubing hydraulic oscillator.It is found that flow rate,fluid density and rotor eccentricity have the greatest impact on its axial force.The example calculation shows that the maximum axial force of coiled tubing hydraulic oscillator increases with the increase of fluid density,flow rate and rotor eccentricity;the change frequency of axial force of coiled tubing hydraulic oscillator is independent of fluid density,and increases with the increase of flow rate and decreases with the increase of rotor eccentricity.