基于附壁效应的水力振动工具研制

Development of hydraulic vibration tool based on Coanda effect

针对现有水力振动工具存在工作压降大、耐腐蚀和耐高温性能差、寿命短、成本高等问题,根据附壁效应和旋流器的工作原理,设计了一种新型水力振动工具。该工具利用特殊流道和钻井液循环产生周期性振动,结构简单、无活动部件、工作压降小。文中利用流体动力学软件模拟研究了该工具的工作特性及影响因素,结果表明:随着入口流量的增大,进出口压降幅值、平均压降以及振动频率均逐渐增大;随着钻井液密度的增大,进出口压降幅值和平均压降逐渐增大。采用响应曲面法建立了进出口平均压降数学模型,室内实验验证了该数学模型的可靠性。工具适用排量为20~35 L/s,冲击力大于30 kN,振动频率大于10 Hz。现场试验表明,基于附壁效应的水力振动工具可减少钻井定向过程中的托压现象,提高钻井效率。

The hydraulic vibration tool generally has such problems as large pressure drop, poor corrosion resistance and high temperature resistance, short life and high cost. In response to these problems, a new type of hydraulic vibration tool was designed based on the Coanda effect and the working principle of the cyclone. The tool can generate periodic vibration by using the special flow channels and drilling fluid circulation. It has the characteristics of simple structure, no moving parts and small pressure consumption. In this paper, the working characteristics of the tool and its influencing factors were studied by using computational fluid dynamics software. The results show that with the increase of inlet flow rate, the pressure drop amplitude, average pressure drop and vibration frequency increase gradually;with the increase of drilling mud density, the pressure drop amplitude and average pressure drop increase gradually. Response surface methodology was adopted to establish the mathematical model for the average pressure drop between the inlet and outlet. The laboratory experiments show that the model used predict the average pressure drop of the tool is effective, the applicable displacemeng for the tool is 20-35 L/s, the impact force generated by the tool is greater than 30 kN, and the vibration frequency is greater than 10 Hz. It provides theoretical guidance for the field application of the tool. The field tests show that the hydraulic vibration tool based on the Coanda effect can reduce the backing pressure on the orientation process and improve the drilling efficiency.