Corrosion Behavior Research Of L360 Steel In H₂S/CO₂ System

With the development of oil and gas industry, the corrosion of metal materials in H2S/CO2 system restricts the development and production. Therefore, it is imperative to study the corrosion behavior and mechanism of metal materials. In view of this situation, the corrosion behavior and mechanism of L360 steel was studied, and a corrosion prediction software in sour gas environment was developed.The influences of salinity, sulphur content and temperature on corrosion behavior of L360 steel in H2S/CO2 system and couple corrosion were studied by means of weight loss method, electrochemical techniques, SEM, EDS and XRD. The results are as follows:(1)The corrosion rate of L360 steel increases at first and then decreases with increasing of brine salinity. The peak of corrosion rate appears at 67864mg/L of brine salinity. Corrosion products- FeS1-x (Mackinaw) films are formed on the surfaces of the samples. H2S corrosion is the main one.(2)Elemental sulphur could accelerate the corrosion rate of L360 steel, and cause serious localized corrosion. The corrosion rate increased with the sulphur content and temperature increased. The peak of corrosion rate appears at 20g/L of elemental sulphur and 70℃.(3)Galvanic current density and galvanic effect between L360 steel and Cr13 steel increase with increasing the ratio of cathodic and anodic areas.An aritifical neueal network(ANN) model for the prediction of the corrosion rate of L360 steel in H2S/CO2 environment, neural network architecture is 5-4-1. After the succession of training, the model is applied to predict the corrosion rate of L360 steel in H2S/CO2 environment. The results show that the forecast results of network model check with the experimental date, the comparative error is less than 14%.