摘要
针对现有水力振荡器的阀盘接触压力高、零件冲蚀及磨损严重、自身压耗偏大,且螺杆马达工作寿命短的问题,研制了一种采用涡轮马达作为动力系统的水力振荡器。该水力振荡器通过涡轮马达将钻井液的动能转化为机械能并驱动阀系产生周期性变化的脉冲压力,该脉冲压力作用在振荡短节使工具产生周期性高频轴向往复蠕动,改变钻柱与井壁间的摩擦状态,减小摩阻、提高机械钻速和钻压传递效率。采用理论计算及滑移网格技术进行CFD仿真的方式,重点研究了阀芯的运动规律及脉冲单元压降随阀芯转角的变化关系。结果表明:阀系开口的连通和关闭改变了流场结构,使得阀系脉冲压力发生周期性变化;采用滑移网格技术可真实地模拟阀系流场结构变化所导致的压力场和速度场的变化情况,提高了水力振荡器的研制效率,并为其优化设计提供了技术支持。滑移网格技术能够满足水力振荡器理论设计的要求,并可弥补试验研究的高成本、长周期等缺陷。
To address the current hydraulic oscillator’s problems of high contact pressure of valve discs,severe erosion and wear of parts,large pressure drop,and short working life of screw motor,a hydraulic oscillator using turbine as the power system was developed.The hydraulic oscillator converts the kinetic energy of drilling fluid into mechanical energy through the turbine motor and drives the valve system to generate a periodically changing pulse pressure.The pulse pressure acts on the oscillating device to generate periodic high-frequency axial reciprocating creep.The improved friction state of drill string with the well wall reduces friction,improves mechanical drilling speed,and improves the weight-on-bit transmission efficiency.Theoretical calculation and sliding grid technology for CFD simulation are used to study the valve core movement and the relationship between the pulse unit pressure drop and the valve core rotation angle.The results show that the opening and closing of the valve system changes the flow field structure,which causes the periodical pulse pressure of the valve system.The sliding grid technology can simulate the pressure field and velocity field caused by the change of the valve system flow field structure,which could improve the development efficiency of the hydraulic oscillator and provided technical support for its optimization design.
作者
倪华峰
李国宏
Ni Huafeng;Li Guohong(Changqing Drilling Company,CNPC Chuanqing Drilling Engineering Company Limited;Engineering Technology Department of PetroChina Changqing Oilfield Company)
出处
《石油机械》
北大核心
2020年第4期31-36,共6页
China Petroleum Machinery
关键词
水力振荡器
脉冲压力
滑移网格技术
CFD仿真
hydraulic oscillator
pulse pressure
sliding grid technology
computational fluid dynamics simulation
