ABSTRACT
There are two major differences on force between suck-rods in polymer-flooding directional wells and water-flooding directional wells. First of all, the polymer-flooding produced liquid contains elasticity as well as viscosity. The visco-elastic fluid flowing in the eccentric annulus between the wellbore and suck-rod will inevitably produce radial forces [1-5]; secondly, there is a certain inclination in the directional wells, gravity on directional well suck-rods inevitably contains the transverse component. In the direction perpendicular to the axis
1 INTRODUCTION
As the number of water-flooding to polymerflooding wells increases, oil recovery is improved markedly, but at the same time new technology problems in the production process have gradually emerged. One of the most serious problems is, after taken the anti-eccentric wear measures of whole well rod centralizing, eccentric-wear of the suck-rods in big slop segment is still serious. Therefore, it is necessary to further study on stress and deflection calculation methods of directional well suck-rods, thus to put forward to the effective measures to prevent the eccentric-wear. Based on the analysis of the stress on suck-rods in the polymer-flooding directional wells, the force on directional well suck-rods in detail and the reasons of eccentric-wear of sucker rod in polymer-flooding directional wells were analyzed, the optimization method of anti-eccentric wear measures were proposed. The results show that: polymer flooding pumping rod in directional well is suffered by the force of the longitudinal force such as fluid drag force and inertia force, and at the same time it is
direction. Take out a suck-rod in polymer flooding wells and directional wells respectively, the stress conditions is as shown in Figure 1. In Figure 1, q represents the radial force of suck-rod, which is uniform load; G represents suck-rod gravity, and is also the uniform load; Fi represents the inertia force of suck-rods in the process of movement; Ff represents the frictional resistance acting on suckrods, the inertial force and frictional resistance are in alternating state in a campaign period [6]; F1 and F2 represent the forces of the other suck-rods on lower and upper side acting on this suck-rod; F3 and F4 represent the forces of the other centralizers on the lower and upper side acting on this suck-rod.
