Study On Corrosion Rules And Protective Measures Of Effusion Package In Sunan Eighteenth Station

With the expansion of gas production,reserves of gas and formation energy decrease sharply that make gas moisture content increase and some gas well more serious.Under the circumstances,there exists seriously corrosion of effusion package in well block,especially in Sunan thirteen station,corrosion rate 2.30mm/a that has a serious influence on normal production.Therefore,it is necessary to study on corrosion mechanism and protection measures of effusion package.In this paper,based on effusion package in Sunan eighteenth station,influence rules in different factors were researched by water physical and chemical property analysis,weight loss experiment,electrochemical test and corrosion product analysis,and three protection measures were selected by eight loss experiment,electrochemical test and numerical simulation.There includes the following aspects:?1?The analyzing results of water show pH nearly neutral,uneven general corrosion and corrosion products mainly for FeCO₃.Therefore,there exists serious CO₂ corrosion in effusion package.?2?The results of studying on environmental and process factors include the followings.With Cl^-concentration increasing,the corrosion rate decreases and gradually keeps flat.The smaller the pH,the more prone to corrode,and corrosion is most serious in neutral solution.With the increase of O₂ concentration,corrosion rate is increasing,and corrosion form changes from general corrosion to localized corrosion.With CO₂ concentration increasing,the corrosion rate and nonuniformity of general corrosion increase.With pressure increasing,corrosion rate decreases,and general corrosion form is more uniform.With the increase of temperature,corrosion product film translates from monolayer film into double membrane,and eventually into a uniformal general corrosion;and accumulation rate of corrosion products in the specimen surface is faster,but bonding force is weaker.When the temperature is high?60??,there is little corrosion products in specimen surface.With the increase of flow rate,corrosion morphology is mainly uneven general corrosion and corrosion product particle is smaller,and local corrosion get worse.?3?Protection measures including corrosion inhibitor,coating and cathodic protection were selected.The optimal corrosion inhibitor is DNS-03,and concentration of 100ppm is best.The optimal coating is HCC,and polarization resistance in thickness of 500?m is largest,up to 5.38×10¹⁰?.The optimal sacrificial anode is AC-3 aluminum anode,and 4 pieces are uniformly distributed at the bottom of effusion package,distance 150mm and bolt connection,and life of sacrificial anode for 21 years.