钻井水射流附壁振荡短节的频率和压降分析

水平井、大位移井等复杂井在钻进过程中会出现大摩阻、钻压拖拽等问题。水力振荡器可以有效降摩减阻、提高钻井效率,而侧壁高度、侧壁角度、劈尖距离及反馈角度等结构参数是影响振荡短节振动特性的关键因素。在阐明水力振荡器工作原理、进行理论分析的基础上,利用CFD数值模拟方法及单因素分析法研究了结构性能参数变化和振荡器压降频率之间的关系。研究结果表明:振荡短节压降、和振荡频率随侧壁角度的增大而增大,且振荡频率逐渐趋于稳定; 随着侧壁高度的增大,压降和频率呈现先降低后上升的趋势,且在侧壁高度2 mm时达到最低值; 劈尖距离增大,压降和频率逐渐降低; 反馈角度增大时,振荡频率基本保持不变。研究成果对射流式水力振荡短节的设计及结构优化具有一定的指导意义。

Frequency and Pressure Drop Analysis of Walling Oscillation Subsection of Drilling Water Jet

In complicated wells such as horizontal wells and extended reach wells,problems such as large friction and drag on the bit during the drilling process occurs.The hydraulic oscillator can effectively reduce friction and drag and improve drilling efficiency.Structural parameters such as sidewall height,sidewall angle,wedge distance,and feedback angle are the key factors that affect the vibration characteristics of the oscillating pup.Based on clarifying the working principle of the hydraulic oscillator and conducting theoretical analysis,the relationship between the change of structural performance parameters and the frequency of the oscillator’s voltage drop was studied by using the CFD numerical simulation method and the single factor analysis method.The research results show that the pressure drop and the oscillation frequency of the oscillation nipple increase with the increase of the sidewall angle,and the oscillation frequency gradually tends to be stable;with the increase of the sidewall height,the pressure drop and frequency show the first decrease and then increase When the height of the sidewall is 2 mm,the minimum value is reached;the distance between the wedge tips increases,and the pressure drop and frequency gradually decrease;when the feedback angle increases,the oscillation frequency remains unchanged.The research conclusions obtained have a certain guiding significance for the design and structural optimization of jet hydraulic oscillation sub-joints.