In-situ electrochemical corrosion behavior of oil well tubing in CO₂-containing highly mineralized oilfield produced water: Revealing the effect of temperature

Abstract The in-situ electrochemical corrosion behavior of oil well tubing at 80 °C and 150 °C in highly mineralized oilfield produced water was investigated by conventional electrochemical methods. The results indicated that N80 steel is controlled by charge transfer in the initial-corrosion stage (2-8 h) of 80 °C, and the corrosion rate weakens with the accumulation of corrosion product films. The post-corrosion stage (12-72 h) is controlled by a combination of reactive adsorption and charge transfer, and the adsorbed intermediates lead to enhanced reactive dissolution of the substrate, which promotes corrosion. At 150 °C, the electrochemical corrosion in the initial-corrosion stage (2-24 h) is controlled by the diffusion process. In the post-corrosion stage (12-72 h), the double-capacitance resistance characteristic exhibits the active deposition state, and the corrosion process is weakened. In addition, the kinetic potential polarization curves at both temperatures indicate that the corrosion product layer has pseudo-passivation properties. The increase in temperature contributes to the nucleation and growth of carbonate crystals, and the mixed FeCO 3 and CaCO 3 film at 150 °C is more protective than the amorphous layer structure at 80 °C.