Internal corrosion in oil and gas wells during casings and tubing: Challenges and opportunities of corrosion inhibitors

Background: Casing and tubing for oil and gas wells are frequently made of steel alloys. Many corrosive gases, organic acids, salts, and other contaminants are present in the fluids of oil and gas wells, which hurt their productivity, efficiency, and continuous production. The common corrosive species include carbon dioxide (CO₂), hydrogen sulfide (H₂S), water (H₂O), organic acids (HCOOH, CH₃COOH etc.) and salts (NaCl, CaCl₂, MgCl₂, NH₄Cl etc.) that can cause the corrosion of metals at any stage of production, purification, storage and transportation processes. Methods: The purpose of the current article is to cover the corrosion of oil and gas well casing and tubing and corrosion mitigation techniques. Significant Findings: Numerous factors influence the corrosion rate in these wells, and various management techniques and procedures have been implemented to address corrosion-related problems in oil and gas wells. Corrosion-resistant materials are one of the most popular and frequently used techniques. To prevent internal pipeline corrosion, anti-corrosive and wear-resistance coatings are also utilized. Another frequent method against corrosion is using scavengers, primarily for H₂S and O₂, to lessen the corrosivity of the well fluids. The most popular H₂S-scavenging technique uses alkaline solutions and activated carbon. Triazine and aldehydes are the most common and efficient non-generative H₂S scavengers. The use of corrosion inhibitors is one of the most practical and cost-effective ways to prevent corrosion in well casing and tubing. The corrosion inhibitors adsorb at the point where corrosive fluids and internal pipelines interface, preventing the corrosive attack.