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Since the centerline of the drainage pipe in the crude oil tank is about 300 mm higher than the bottom of the tank, and due to factors such as liquid viscosity and unevenness in the tank bottom, sedimented water remains at the bottom of the tank over time. Moreover, because the mineralization degree of the aqueous solution is high, electrochemical corrosion occurs primarily. The corrosion of the water phase in the tank is mainly caused by the following factors: (1) The influence of Cl-. Cl- has a small diameter and strong penetration ability, so it preferentially adsorbs at the areas where the coating peels off or cracks. Due to the poor mobility of sludge at the bottom of the tank, rust layers, and pitting defects, pitting nuclei form on the surface of the tank bottom, which gradually grow into sources of cavitation corrosion. In these areas, the metal undergoes severe local acidification, leading to an increase in ion concentrations; this results in a corrosion pattern characterized by a large cathode and a small anode, thereby intensifying local corrosion. (2) Effects of H2S, CO2, O2. CO2 and O2 in the air have difficulty diffusing into the sedimented water layer; although the concentration of these gases at the bottom of the tank is low, some air is introduced during oil collection and discharge processes, so the aqueous solution does not form a completely anaerobic environment. H2S gas plays an important role among the factors that cause gas corrosion in storage tanks; when it dissolves in water, it forms a weak acid that releases H+, giving it strong corrosive properties. Meanwhile, H2S acts as a catalyst, accelerating the reduction process of H+ at the cathode and leading to sulfide stress corrosion. After dissolution, this sulfur compound forms a high-strength sulfidic acid, which further exacerbates the corrosion. (3) Effect of conductivity. According to the principles of corrosion electrochemistry, the higher the conductivity of the water deposited on the tank bottom, the greater the corrosion current in this system. This indicates that the higher the mineralization degree of the water deposited on the tank bottom, the higher the ion concentration, the lower the resistance, and the more severe the corrosion.