水力振荡器振动特性对减阻规律的影响研究

Effects of vibration characteristics of hydraulic oscillator on friction reduction law

为了掌握水力振荡器振动特性对减阻规律的影响,基于Lu Gre摩擦理论,建立了钻柱与井壁岩石间摩擦力的计算模型,得到了水力振荡器的单因素振动特性对钻柱与井壁间摩擦力的影响规律;利用正交试验,分析水力振荡器振动强度、振幅、振动频率综合作用下对钻柱与井壁岩石间摩擦力的影响。研究结果表明:提高水力振荡器振动强度、振幅、振动频率均能降低钻柱与井壁岩石间摩擦力,其中摩擦力随振动频率的增大呈现先增强后减弱趋势,在振动频率大于20Hz时,各振动强度对应的减阻效率有下降趋势,最佳振荡频率为22Hz;水力振荡器各振动特性对钻柱与井壁岩石间摩擦力影响显著性由大到小,依次为振动强度、振幅、振动频率。

In order to understand friction reduction law of vibration characteristics of hydraulic oscillator, based on Lu Gre friction theory, the influence of single factor about the vibration characteristics of the hydraulic oscillator on the friction force between the drill string and the borehole wall is obtained by the established calculation model of the friction between the drill string and borehole wall rock, and then the influences of vibration intensity, vibration amplitude and vibration frequency on the friction force between drill string and borehole wall are analyzed by orthogonal test. The results show that with the increase of hydraulic oscillator strength, the vibration amplitude and vibration frequency, the friction between the drill string and borehole wall rock decreases. With the increase of the vibration frequency, the friction force increases first and then decreases, when the vibration frequency is greater than 20 Hz, the efficiency of drag reduction of vibration intensity shows a downward tendency, and the optimal oscillating frequency is 22 Hz. The vibration characteristics of hydraulic oscillator have significant effects on the friction between drill string and borehole rock, the order of significance from large to small is vibration intensity, vibration amplitude and vibration frequency in turn.