Study On Scaling And Corrosion Mechanism And Influencing Factors Of ASP Flooding Wellbore

Daqing Oilfield is in the middle and late stage of production,and the produced fluid carries a large amount of scale-forming ions from the formation.During the whole production process,the changes of temperature,pressure,flow rate and other parameters will cause the original balance to be broken,causing the scale-forming ions to collide with each other.The scale particles formed by the chemical reaction coalesce and deposit on the wall of the cylinder,resulting in scaling.The accumulation of scale will not only lead to blockage of the wellbore,but also cause corrosion under the scale,causing irreversible damage to the wellbore.It seriously affects the safety of oil production and high economical and efficient operation.In view of the scaling and corrosion problems in the production process of production wells,the following researches are carried out in this paper:1.By studying the mechanism of wellbore scaling and corrosion,it is found that under the influence of various factors,the production well will induce scaling.Therefore,by analyzing the components of the produced fluid on site and combining with the production status of Daqing Oilfield,it is found that the produced fluid contains a large amount of bicarbonate ions,carbonate ions,calcium ions and other scaling ions;Scale Chem software,which is more suitable for the current situation of Daqing Oilfield,can be used for fouling prediction and simulation analysis.It was found that the scale type was mainly calcium carbonate,which was in line with the actual situation on site.2.Based on the predicted data,the indoor static scaling and corrosion experiment was carried out to study the scaling and corrosion mechanism of the production well in Daqing Oilfield.By analyzing the experimental scale samples,it is concluded that the main type of scale samples is calcium carbonate,which verifies the accuracy of the prediction and simulation.The carbonate ions,bicarbonate ions,calcium ions and barium ions carried in the produced fluid are the main reasons for the formation of this scale.As the concentrations of carbonate ions and sulfate ions increase,the amount of scaling and corrosion will increase;as the concentration of bicarbonate ions increases,the amount of scaling will increase and the amount of corrosion will decrease;with the increase of p H value,the amount of scaling and corrosion will increase.The amount of corrosion will decrease.And the fouling experimental data is consistent with the software prediction trend.3.Based on software prediction data and laboratory experiment data,establish a prediction model of wellbore scaling rate in production wells,and use field data of production wells in Daqing Oilfield to study calcium carbonate scale particles at the upper stroke pump,the lower stroke pump,and the sucker rod.Mass fraction distribution of the three locations at the collar.The mass fraction distribution of calcium carbonate scale particles was simulated and analyzed by changing the initial inlet flow rate and the scaling ion concentration.Provide reasonable mining suggestions and theoretical basis for the site.