The Dynamics Analysis Of Rod String In Screw Pump Well And Research Eccentric Wear Prevention Methods

As new artificial lifting equipment, Screw pump production system is widely used on oil field as its simple structure, high pump efficiency, and energy saving and so on. But as screw pump oil product technology further generalized, the eccentric wear of rod string problem is more and more serious, it restrict the production efficiency seriously. So analysis the eccentric wear reason of rod string and provide eccentric wear prevention method is practical significance.This article mainly analysis the surface driven screw pump system. At first do statistic analyses to eccentric wear data of 2006 and 2007 years of screw pump well, and know that rotation speed, submergence depth radius of rod and the location of centralizer are all affect pump detection period.Analysis screw pump system, get the mechanical model of rod string, deduct and calculate undertaking load of rod string. Establish the finite analysis model of rod string through simplified the boundary conditions. Taking for 10-2435 well, calculating result is mainly accordance with engineering practice situation. It shows that the correctness of this calculation method. On the base of this calculation method, comparative analysis calculating result, and know that the well body structure,motion state,centralizer location,working parameters and vibration etc are mainly factors which lead rod string to eccentric wear. Do model analysis,transient dynamic analysis and kinematics analysis etc by using finite analysis software ANSYS. Considering the effect of well body structure,rotational speed,submerge degree,centralizer layout etc in the calculating process. Taking for 10-2435 well arrangement centralizers again, decrease lateral displacement of rod string effectively, furthermore reduce eccentric wear.Non vertical of well body structure is mainly factor which cause eccentric wear, its mainly present at deviating axis position under gravity action. Rod string of high speed will generate lateral displacement under the effect of centrifugal force. So fully considered the particularity of well body, making different schemes separate, the calculating result shows that the new method reduce the eccentric wear effectively. This method have reference value to centralizer's location scheme.The study of this method is inosculated with engineering. Establishing the finite model of rod string which can show the real motion state and stressing state basically. So calculation analysis to this model will have guiding significance to actual situation.