Fracturing String Corrosion And Corrosion Inhibitor Screening Study Of Daqing Oil Field

With the rapid development of petroleum industry,the acidic gas such as CO₂ corrosion problem has become the important problem of the rapid and efficient gas field development,in order to solve this situation,need to analyze the corrosion law of fracturing string,and based on this screen is suitable for well killing fluid corrosion inhibitor.In this paper,the reason of corrosion failure of the fracturing pipe column is firstly studied,and the local corrosion of the oil pipe is found when the tubing is submerged in the pressure well.The surface of the tubing corrosion phenomena of well killing fluid is made up of O₂ and CO₂ joint caused by corrosion,and the existence of a large number of active chlorine ion in the kill fluid,accelerate the occurrence of pitting corrosion under the scale,promote each other,three types of corrosion caused the serious corrosion of tubing.And think well killing fluid in formation under the action of high temperature and long time,well killing fluid in progressive loss of moisture,salt precipitation outside the tubing wall,form a layer of dirt,creating a little bit of corrosion conditions,and on the inner wall of the tubing,moisture can't loss of well killing fluid,so the formation of scale,so corrosion is lighter,so should avoid as far as possible on the downhole tubing for a long time.After corrosion law of different well killing fluid system was studied,and comprehensive comparison of the N80 steel,13 cr stainless steel corrosion rate in the three kinds of high pressure well liquid,can obtain the corrosive order: KCl > pressure well liquid > NaNO₃ pressure well liquid sodium formate well killing fluid.Against corrosion is most serious after KCl-N80 steel of well killing fluid system,and evaluated the effect of different corrosion inhibitor on the corrosion of N80 steel,found that potassium silicate and polyacrylamide with 1:1 distribution when using,the corrosion effect can reach more than 90%.The corrosion inhibitor formulations Yu Daqing peripheral gas field application,the pipeline corrosion detection on corrosion inhibitor filling everywhere,test results show that belongs to the mild corrosion,the corrosion effect is good,which have been proved successful in daqing peripheral field corrosion control applications.