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The key prerequisite for hydrogen sulfide corrosion in oil and gas fields is that H₂S must be dissolved in water to be corrosive. There are mainly two mechanisms of action: First, the electrochemical corrosion process – when H₂S dissolves in water, it ionizes to produce H⁺, HS⁻, and S²⁻, creating a weakly acidic environment that triggers the anodic dissolution reaction of iron: Fe → Fe²⁺ + 2e⁻; simultaneously, a hydrogen evolution reaction occurs at the cathode: 2H⁺ + 2e⁻ → H₂, thereby continuously causing the metal layer on the pipe walls to thin out. The FeS corrosion product formed as a result of the reaction has crystal structure defects, which allow it to form electrochemical microcells with the steel matrix. As the cathode, FeS accelerates the local dissolution of the metal, further intensifying the corrosion process. II. During the hydrogen-induced damage process, the hydrogen atoms released react and penetrate into the steel, where they accumulate at inclusions and grain boundaries to form H₂ molecules. This creates localized high pressures that lead to hydrogen embrittlement (HB) and hydrogen-induced cracking (HIC). If residual stress exists in the equipment, hydrogen atoms will accumulate in areas under triaxial tensile stress, leading to brittle fracture failures such as sulfide stress corrosion cracking (SSCC) and stress-oriented hydrogen-induced cracking (SOHIC).