自吸环空流体式自激振荡脉冲粒子射流调制机制分析

基于现有技术分析,提出利用环空水力能量在井下调制脉冲粒子射流用于硬地层钻井提速的技术设想。模拟分析所提出的自吸环空流体式自激振荡脉冲射流调制元件吸入环空粒子,并振荡加速形成脉冲粒子射流的机制。结果表明:随着围压、粒径、粒子密度和泵压的增大,粒子在自激振荡腔室内的停留时间逐渐缩短,运行轨迹趋于简化;粒子出口速度随着围压、粒径和泵压的增大而增大,随着粒子密度的增大呈先增大后减小的趋势,存在最优粒子密度。研究结果证实了井下调制式脉冲粒子射流钻井方法的原理可行,为实际钻井技术的发展提供了重要依据。

Mechanism analysis for self-oscillation pulse particle jet based on automatic fluid sucking from annulus

Based on the existing technology of pulse particle jet assisted oil well drilling, a method using the hydraulic power in annulus to modulate the pulse particle jet was proposed to increase the penetration rate. The sand or metal particles in annulus can be automatically sucked into a modulating component or chamber that has self-priming and self-oscillation functions to generate pulse particle jet. The mechanisms of the process and its influencing factors were studied by numerical simulation. The results show that with the increase of the ambient pressure, particle diameter, particle density and pump pressure, the residence time of particles in the self-oscillation chamber can be shorted and their moving trajectory is straighten out gradually. The exit velocity of the particles increases with the increase of the ambient pressure, particle diameter and pumps pressure, but increases firstly and then decreases with the particle density increasing, so there is an optimum particle density. The results indicate that the modulated pulse jet technique is plausible in principle and can form an important basis for the improvement of the drilling technology.