High temperature sweet corrosion and inhibition in the oil and gas industry: Progress, challenges and future perspectives

Sweet corrosion is one of the most often encountered type of corrosion of steel materials in oil and gas production wells and also a major cause of serious corrosion–related material failure in the industry. The use of corrosion inhibitors is one of the most economical methods of controlling sweet corrosion. Corrosion inhibitors applied under bottom-hole temperatures up to 100 °C are usually stable and generally show no technology-related problems in their performance. Above this temperature, however, the literature report of corrosion inhibitors is relatively scarce. This poses a serious challenge to controlling sweet corrosion as drilling operations now drift to deeper wells with higher temperature and pressure. Consequently, no scientific or patent review on corrosion inhibitors for sweet corrosion at high temperature is visible in the literature. Therefore, a thorough review of high-temperature sweet corrosion inhibitors is important. Herein, we review scientific research publications and patents related to corrosion inhibitors reported for sweet corrosion of steel at temperature at least 90 °C. Nitrogen–based compounds are the most widely used inhibitor chemistries. Research gaps still exists on localized and high total dissolved solids (TDS) brine high temperature sweet corrosion inhibitors. Future research directions have also been highlighted.