Decoding for Commercial Corrosion Inhibitor in Oil and Gas Production: Unveiling the Multifaceted Corrosion Dynamics and Protective Strategies

Abstract This study presents a comprehensive electrochemical evaluation of a commercial corrosion inhibitor for carbon steel in a simulated oilfield brine (3.5% NaCl) under acidic conditions (pH 3.4). The performance and mechanism were investigated using open circuit potential monitoring, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). The inhibitor demonstrated a concentration-dependent efficacy, with 100 ppm identified as the optimal dosage. At this concentration, a high inhibition efficiency of 93.8% (from polarization) and a significant increase in charge-transfer resistance (from 3.1 to 20.2 kΩ·cm 2 ) were achieved. Analysis of the electrochemical parameters revealed a mixed-type inhibition mechanism with predominant anodic control, attributed to the strong adsorption of the inhibitor molecules onto the steel surface. This adsorption, facilitated by functional groups such as –NH₂ and –C=O, forms a protective film that increases surface homogeneity and effectively blocks active corrosion sites. While the study establishes a robust performance baseline and mechanistic understanding under controlled laboratory conditions, it also highlights the necessity for future validation under dynamic flow and long-term exposure scenarios to fully assess field applicability. The findings provide critical data for the informed selection and application of inhibitors in corrosive, chloride-containing environments.