基于有效牵引力系数的水力振荡器减阻效果评价方法

A Evaluation Method for Drag Reduction Effect of Hydraulic Oscillator Based on Effective Tractoring Force Coefficient

水力振荡器的优化设计和合理使用受到水力振荡器减摩阻效果评价标准不够完善的影响,为此建立了钻柱轴向振动传播模型,提出用有效牵引力系数评价水力振荡器的减摩阻效果,并基于此研究了有效牵引力系数的影响因素。研究表明:水力振荡器产生的有效牵引力系数随着机械钻速的增加而降低;激振力幅值和振荡短节碟簧组刚度对减摩阻效果有较大影响,而激振频率的影响较小;有效牵引力系数随着水力振荡器离钻头距离的增加而先增加后趋于平稳,最佳的工具安放位置为有效牵引力系数达到平稳的第一个位置点。

The standard for evaluating the drag-reduction effect of hydraulic oscillators is not perfect,which affects the optimal design and reasonable use of hydraulic oscillators.For this reason,the axial vibration propagation model of drill string is established,and it is proposed that the drag-reduction effect of hydraulic oscillator is evaluated using an effective tractoring force coefficient.Based on this indicator,the influencing factors of the effective tractoring force coefficient are studied.The results show that the effective tractoring force produced by the hydraulic oscillator decreases with the increase of ROP.The amplitude of excitation force and the stiffness of the shock tool disc spring group have great influence on the drag-reduction effect,while the excitation frequency has little influence.As the distance between the hydraulic oscillator and the bit increases,the effective tractoring force coefficient increases first and then tends to stabilize.The optimal tool placement position is where the effective traction coefficient reaches a stable value for the first time.