Study On Corrosion Regularity And Residual Life Prediction Of Production Pipeline In Panyu 30-1 Platform

Several kinds of corrosive gas can be found from the natural gas of Panyu30-1gas field, like H2S and CO2, produced-water not only is acidic, but also contain HCO3-and Cl-. Under high-temperature and high-pressure environments, these substances can make the pipeline corrosion easily. The failure incidents caused by corrosion can bring some serious consequences. So it is necessary to study the corrosion reason of pipelines on Panyu30-1platform and forecast their remaining life. This paper selects the corrosion pipelines of4-PW-1002-E5-P,8-PV-2060-E2,12-PV-1010-E5and6-WS-4064-A5and their material quality (16Mn steel,20#steel and duplex stainless steel F51) as study materials, and study their corrosion reason with energy spectrum analysis, X-ray diffraction, evaluation of soldered joint, evaluation of HIC-resistance property, electrochemical experiment and so on. What is more, calculate their corrosion speed with stimulating site environment experiment based on loss-weight method. At last, evaluate the pipeline’s residual intensity based on AIP579and SY/T6151-2009, then forecaste remaining life with uniform corrosion and test data remaining life prediction model if the four pipelines’residual intensity are confirmed qualified. The main conclusion including:(1) The corrosion mechanism of4-PW-1002-E5-P pipeline is SRB, HCO3-and stress corrosion by Cl-, the mechanism of both8-PV-2060-E2and12-PV-1010-E5pipelines is H2S, CO2, HCC>3-and stress corrosion by Cl-, the mechanism of6-WS-4064-A5pipeline is dissolved O2in the sea by Cl-.(2) Accroding to visual and radiographic inspection investigation, Several external and internal defects can be found on soldered joints. What is more, the tensile property of all the soldered joints are not qualified. Meanwhile, some soldered joints are not qualified in both tenacity and hardness properties.(3)4-PW-1002-E5-P,8-PV-2060-E2,12-PV-1010-E5and6-WS-4061-A5pipelines conform to present operating request. The remaining life of8-PV-2060-E2is16a, while the other three pipelines satisfy the design life of20a.In conclussion, Cl-, H2S, CO2, HCO3-and SRB are the main corrosion reason. What is more, although4-PW-1002-E5-P,8-PV-2060-E2,12-PV-1010-E5and6-WS-4064-A5have suffered corrosion, they can go on working right now.