Abstract
Organic corrosion inhibitors (CIs) are widely used in the oil and gas industry to control pipeline corrosion. Batch treatment is a method commonly used to apply CIs for top-of-the-line corrosion mitigation in gas lines and in downhole tubulars. In this approach, the CI forms a thick protective film on the pipe surface, but this film gradually degrades due to various factors, leading to loss of inhibition. Therefore, understanding CI persistency and the parameters affecting its degradation is critical for improving the efficacy of batch treatments. A novel methodology and experimental setup were developed to address previous limitations and investigate CI persistency under batch treatment conditions. This setup effectively removed all CI residuals after application and prevented oxygen contamination during the film formation step. A commercial inhibitor was used to study the effects of temperature, presence of hydrocarbon, and contact time on CI persistency, by application in situ on API 5L X65 steel inside a deoxygenated glass cell. In addition, different model compound CIs with different solvents/carriers were tested for investigating their persistency. Electrochemical measurements were taken at intervals to track inhibitor performance over time.
