Research On The Reasons And Influence Factors Of Pipe Rod Corrosion Of Polymer Flooding Oil Well

In oil and gas field development，corrosion of metal seriously affected the normal oilproduction, resulting in greater economic losses. By coupon corrosion weightlessness method,the paper aims at exploring the reason and influence factors of pipe rod corrosion of polymerflooding oil well in Shengli oilfield Gudong oil production plant. A few studies as followswere conducted in this paper: first, the degree of metal corrosion in polymer solution withdifferent concentrations, different molecular weights and different degree of hydrolysis werestudied，the results show that with the increases of concentration, molecular weight of HPAM,the metal corrosion rate in solution is decrease. However, with the degree of hydrolysis ofHPAM increase, the metal corrosion rate in solution is also increase. Second, how the salinityor ion composition of the experiment solutions and the environments of the solutionsinfluence on metal corrosion were studied. The results show that with the increase ofsalinity(except HCO-and CO32-), metal corrosion rate in mixture solution also increases. Thecorrosion rate in mixture solution with HPAM is littler than that without HPAM in mixturesolution as other conditions are same; when there are HCO-and CO32-in mixture solution, thecorrosion rate is decrease with the concentrations of HCO-and CO32-increase. All of HPAM,HCO-and CO32-can inhibit metal corrode, and the degree of inhibition by HCO-or CO32-isgreater than mixture between HPAM and HCO-or HPAM and CO32-, and the effect bydivalent ions on corrosion is greater than the effect by monovalent metals; environments(temperature, oxygen content, flow rate, etc.) have a certain impact on the corrosion of metal.With the increases of temperature, the extensions of the time that solutions expose to oxygenand the acceleration of the flow velocity of the liquid, the corrosion rate also increases. Third,polarization curves of metal corrosion in different concentrations or different molecular weight polymer solution were tested by electrochemical workstation, and the corrosionmechanisms of metal in different concentrations and different molecular of polymer solutionwere discussed, the results are same as that by coupon corrosion weightlessness method; forth,the proppant carrying capacity of polymer solution and the influence on eccentric wear bypolymer solution were comprehensive analyzed and researched. Due to the densification ofHPAM, HPAM can increase solution viscosity, in one hand, it increases the sand-carryingcapacity of the produced fluid and leading to the sharpening effect of grit to metal surfaceincreases, on the other hand, HPAM solution as a typical viscoelastic fluid, it adds a normalforce to metal pipe in polymer flooding than water flooding, leading to the sucker rod partialwear heavier. In addition, through research and field data analyses show that HAPM canprovide nutrition for the breed and growth of bacteria exacerbates the corrosion of metal. Atlast, according to the factors that affect corrosion, the basic countermeasures and specificmeasures to prevent or slow down the oil well pipe rod corrosion of polymer flooding wereput forward. Wish this study can provide some reference to solve the serious corrosion of thepipe rod in polymer flooding well.