The Structural Design Of The Linear Drive Screw Pump And System Dynamics Analysis

As the continuous development of petroleum exploitation in our large oil fields,the difficulties of petroleum exploitation increases gradually.Some oil wells have welled up thick oil with high percentage of containing sand and hign ratio between oil and gas.Some oil fields have been in the high-water,even much higher-water exploitative period in the end of water-drive reservoir.If we keep on using the quondam mechanical oil extraction equipments which work with pumping units,the fact of low working efficiency will be arised.It is an ideal method of exploitation to use Progressing Cavity Pump(PCP) in this condition.However, since using any current PCP, a great number of past pumping units will be discarded.The beeline driving PCP is put forward in this paper.It uses the past pumping units and sucker rods as driving devices.It has not only the unique advantages of being fit to extract crude oil with high viscidity,but also the advantages including good adaptability,reliable work,longevity of service and being fit to extract oil in the deep well like rod pumping.At first,this paper introduces the principle of mechanical oil extraction,puts forward the beeline driving PCP oil extraction system,and analyses the movement of the power conversion device in detail.A kind of beeline driving PCP has been designed,and all parts of PCP have been drawed and assembled together with Solidworks.And then,this paper analyses the force of the ball spline and the ball screw in the upward and downward stroke,and establishes their dynamic models.It also analyses the character of kinematics and dynamics about the rotor of PCP detailedly,and establishes its dynamics model.At the same time,the mathematical model about the conventional beam pumping unit is established.This paper analyses the force of sucker rod and establishes its longitudinal vibration mechanical model with one dimension.The longitudinal vibration mechanical models which are based on the mutual function between the sucker rod and the liquid column and among the sucker rod,the liquid column and the oil string are established.Moreover,this paper makes analysis on the reason of distortion about sucker rod,and establishes its torsional vibration model.At the same time,the initial conditions and the boundary conditions are given in every vibration models.At last,the simulation about the beeline driving PCP oil extraction system has been done in the condition of using fixed slip electric moter and taking no account of the sucker rod's elastic deformation.The simulated curve has been drawn with Matlab.We conclude that the fluctuation of the instant rotational speed is high,but the fluctuation of the driving torque is relatively low by analyzing the simulation consequence.It indicates that the beeline driving PCP put forward in this thesis has good characteristic.