地面驱动螺杆泵采油系统启动过程动力学研究

Study of start-up process dynamics of the oil production system with surface-driven progressive cavity pump

综合考虑地面驱动与传动系统的机械特性、杆柱扭转振动、杆柱所受的液体阻尼与负载扭矩,建立了地面驱动螺杆泵采油系统动力学分析的数学模型,该数学模型由描述转盘旋转的动力学常微分方程与描述杆柱扭转振动的波动方程组成,既可以分析螺杆泵采油系统启动过程的动力学特性,也可以分析其停车过程的动力学特性。建立了一种独立模块仿真算法,求解转盘旋转动力学常微分方程组与杆柱扭转振动波动方程所组成的耦合数学模型。开发了地面驱动螺杆泵采油系统动态参数的计算机仿真软件。仿真计算结果表明,对于机械特性较硬的Y系列电动机所驱动的螺杆泵采油系统,电动机在较短时间内就能达到其稳定工作转速,驱动头处有较大的动载扭矩,动载系数随工作转速的增加而增加。当工作转速增加至300r/min时,动载系数达1.3,在对采油杆柱进行强度计算时,有必要考虑动载系数的影响。

The mathematical model for analyzing the dynamics of the oil production system with surface-driven progressive cavity pump is established by taking the mechanical property of the surface-driven and transmission system,the torsional vibration of the rod string and the liquid damping and load torque acting on the rod string into full consideration.This model is composed of the ordinary differential equation(which is used to describe the rotary movement of the rotor)and the wave equation(which is used to describe the torsional vibration of the rod string).It can not only be used to analyze the dynamic behavior of the oil production system during the starting process,but also to analyze the dynamic behavior during the stopping process.A coupling mathematical model is established by using an independent module simulating algorithm to calculate the dynamic ordinary differential equations of rotor rotation and the wave equation of the rod torsional vibration.The computer software of simulating the dynamic parameters of the oil production system with surface-driven progressive cavity pump is developed.The simulating calculation results show that for the oil production system with progressive cavity pump driven by the Y-series motors of low slippage,the motor can get the steady rotation speed in a short time;moreover,the greater dynamic torque acts on the driving shaft,and the dynamic torque coefficient increases with the increasing of the rotary speed.When the rotary speed is equal to 300 r/min,the dynamic load coefficient reaches 1.3.When the strength of the rod string is calculated,it is necessary to consider the influence of the dynamic load coefficient.