Research On The Corrosion Behavior Of Casing Steel In The Produced Liquid

Daqing oilfield has entered high water cut period,in order to improve oil recovery of polymer flooding and asp flooding technology is becoming a important technology to keep stable oil field production after water flooding.Due to polymer flooding,asp flooding agent and various kinds of agents to join such as scale and corrosion inhibitor,complicate the produced components and a variety of flooding coexist,the problems of corrosion and protection in extraction system becomes more complex.In this paper,analysis and research on the asp flooding produced fluid in casing corrosion behavior of steel,and a large number of field test.The concrete research content is as follows:1.The ternary component and the relationship between the casing corrosion.This study using instruments such as the electrochemical workstation,using the orthogonal test and immersion corrosion electrochemical corrosion under the condition of experiment with the combination of research methods to explore and get the following results:NaOH is three yuan components in the main factors affecting casing steel corrosion;Within a certain range,the corrosion rate of steel casing with the increase of the ternary component content decreases after increasing first.In the process of production,unfavorable use higher concentration of NaOH,otherwise will increase the scaling tendency of medium,lead to local corrosion is serious.2.Determine the scale inhibitor and acid wash after joining effluence on the influence law of casing corrosion.This part USES electrochemical experiment method,the determination of N80 steel in different distribution of produced liquid of potentiodynamic polarization curves and electrochemical impedance spectroscopy,orthogonal experimental analysis method of electrochemical experiment results are analyzed.Test and analysis results show that the influence significance of all for casing steel corrosion rate is roughly as anti-scaling agent concentration,temperature and lower residual acid lotion in the order.Alkaline corrosion effect is better,anti-scaling agent on the impact of anti-scaling agent concentration on corrosion rate is the most prominent contribution.3.The corrosion morphology by using scanning electron microscopy(sem)observation,using spectrometer analyzes the composition of corrosion products;Weightlessness method is used to calculate the three types of casing produced fluid medium corrosion rate of steel in composite gentle erosion rate,the results showed that the acidic or alkaline antiscale agent,the corrosion effect is not ideal,in most cases,the addition of anti-scaling agent will accelerate corrosion,acid corrosion inhibitor of three kinds of materials in case more serious than in alkaline antiscale agent.Using uniform experimental method to design the experiment scheme,the use of high temperature and high pressure reaction kettle,with ternary compound produced fluid as a medium for the corrosion of high temperature and high pressure simulation experiment,by using uniform experimental fitting software fitting,data of the corrosion rate under different working conditions,determine the corrosion rate varies with temperature,concentration of anti-scaling agent and the changing rule of the parameters such as pressure and function relationship,to realize the more complex conditions of material corrosion rate under the influence of parameters prediction.