Study on the high-temperature gas field containing H2S sewage corrosive behavior

The sewage from high-temperature gas field containing H₂S has following features: high H₂S content, high temperatures and high salinity. Coupon test, microscopic observation of corrosion images and other methods have been used in the research of the corrosion behavior of high-temperature H₂S-contained sewage to N80 steel. The sewage corrosion behavior to N80 steel starts from the adsorption of sulfur particles, the corrosion products are a variety of iron sulfide and other compounds of trivalent iron, and the iron sulfide formation of passive film shows the trend of densification at high temperature. As the pH value of the sewage decreases, the corrosive enhances, the smoothness and oxide on the surface of N80 steel can affect the corrosion. The increasing oxygen content leads to the higher corrosion effect. In the sewage, the high concentration of CT ions accelerates the N80 steel corrosion caused by S^2- and HS^-. And the HS^- concentration in the sewage is the main factor that influences on the corrosion performance to N80 steel.