井下它激振荡脉冲射流机理研究

Mechanism of oscillating jet induced by external excitation

在油气井钻井中 ,为了充分利用井下水力能量 ,利用井下环空流体液柱压力作为激励源 ,实现了它激振荡脉冲射流。探讨了井下环空流体作为它激源实现它激振荡脉冲射流的机理 ,建立了物理模型。利用室内实验研究揭示了井下水力它激振荡脉冲射流的机理 ,为井下水力增压的研究提供了理论依据。实验结果表明 ,它激共振腔结构参数 (容积 ,上、下喷嘴直径 ,比值 ) ,它激孔位置、数量、直径以及水力参数 (流量、射流速度、环空液柱压力 )是影响它激作用的重要因素。在实验条件下 ,共振腔自增流量为泵入流量的 2 0 %左右 ;

In order to take full advantage of downhole hydraulic energy,a method for oscillating jet induced by external excitation was proposed,taking hydraulic pressure within annulus as external excitation resource.The physical models for achieving oscillating jet induced by pressure within annulus were presented.The mechanism of oscillating ject induced by external excitation was experimentally studied.The experimental results show that the structure parameters including volume,upper and down nozzle diameters of chamber as well as the position,number and diameter of external inducing hole,hydraulic parameters including flow rate,jetting velocity,hydraulic pressure within annulus are the important parameters for oscillating jet induced by hydraulic pressure within annulus.These parameters have important effects on external inducing process.Under the experimental conditions,the self-additional flow rate within resonant chamber is 20 percent of pump flow rate,and the outlet dynamic pressure produced by oscillating jet induced by external excitation is two times of that produced by selfoscillating jet.