Electrochemical corrosion behavior of PI110 tubing steel in annular environment

The effect of solution pH value and H₂S partial pressure on the electrochemical corrosion of PI 10 tubing steel in solutions containing dissolved H₂S/C0₂ in an autoclave, which aimed to simulate the annular service environment, was studied by electrochemical measurements, U-bent specimen immersion test and surface analysis technique. Results indicate that, with the increase of solution pH value and H₂S partial pressure, the corrosion current density of PI 10 tubing steel decreases significantly. H₂S partial pressure suppress the anode reaction of PI 10 tubing steel but enhance the cathode hydrogen permeation, which then promotes crack initiation and increases its stress corrosion susceptibility.