Study On Mechanism Of Influence Of Produced Liquid In Polymer Flooding Wells On Eccentric Wear Between Sucker Rod And Oil Tube

Polymer flooding has been an important enhanced oil recovery method adopted at the later stage of oilfield development in China. But, a problem has been put forward that the rate and degree of eccentric wear between sucker rod and oil tube aggravated in polymer flooding wells than which in water flooding wells since polymer wells put into production. Viscosity of produced liquid elevating lead to friction increasing associated with viscosity. That is, force status of sucker rod and tube turn too bad, and the lengthways compressive loads increased in downstroke. And so, eccentric wear between sucker rod and oil tube become serious, the rate of sucker rod also increased, operating wells obvious add a lot, it must influence the production of polymer flooding well.This article aimed at the problem, obtained polymer sample from field, studied experiment on rheology of produced liquid, including the influence of temperature, concentration and oil content etc on viscosity, regress the consistency coefficient and rheological coefficient of constitutive equation, depicted consistency coefficient and rheological coefficient three-dimensional curve respectively under different temperature and concentration circumstances. Experiment on dynamic shear was carried out, obtaining relationship of composite modulus, loss modulus and storage modulus following change of frequency, getting the relationship of frequency and equivalent point of loss modules and storage modules. Calculation formulas of pumping unit suspension point load were obtained, the distributing forces along the axis direction were analyzed, and the position of neutral point and critical condition of rod and tubing wear were derived. The mathematical models velocity distributions of eccentric annular under the moving to and fro axially for the power-law fluid were deduced. The Maxwell fluid was used to calculate the lateral force in the eccentric annular by using bipolar coordinates conversion. Some factors including water content and submergence depth which is related to sucker rod and oil tube wear were analyzed. Measures of protection eccentric wear, mainly are lower sinker rod and centralizer, were designed and calculated.