Reliable corrosion inhibition in the oil and gas industry RR 1023 Research Report
The objective of the work was to undertake a literature review on the subject of corrosion inhibition in the offshore oil and gas industry to understand the current issues. The application of chemical corrosion inhibitors can significantly reduce the rate of corrosion of carbon steel pipelines due to the presence of CO2 and/or H2S. An inhibited corrosion rate of 0.1 mm/year can typically be achieved, which is largely independent of the uninhibited corrosion rate. The report covers the main factors affecting the effectiveness of chemical corrosion inhibitors; they are not effective against corrosion due to the presence of oxygen or microbacterial corrosion. High flow rates, high temperature, solids (either dissolved or suspended) and pre-existing corrosion can all have a negative effect on corrosion inhibitor effectiveness. The role of Key Performance Indicators (KPIs), the main factors affecting the performance of inhibition injection systems, and the levels of inhibitor availability that can be assumed at the design stage and achieved in practice are also discussed. This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy. You may reuse this information (not including logos) free of charge in any format or medium, under the terms of the Open Government Licence. To view the licence visit Some images and illustrations may not be owned by the Crown so cannot be reproduced without permission of the copyright owner. Enquiries should be sent to Objectives To undertake a literature review on the subject of corrosion inhibition in the oil and gas industry to understand the current issues. Main Findings • The application of chemical corrosion inhibitors can significantly reduce the rate of corrosion of carbon steel pipelines due to the presence of CO 2 and/or H 2 S. An inhibited corrosion rate of 0.1 mm/year can typically be achieved, which is largely independent of the uninhibited corrosion rate; • Various factors can affect the effectiveness of chemical corrosion inhibitors; they are not effective against corrosion due to the presence of oxygen or microbacterial corrosion. High flow rates, high temperature, solids (either dissolved or suspended) and pre-existing corrosion can all have a negative effect on corrosion inhibitor effectiveness; • The main Key Performance Indicator (KPI) used for assessing effectiveness of corrosion inhibitors is based on the proportion of time that …
Localized Corrosion in the Presence of Corrosion Inhibitors at High Flow Velocities in CO 2 Environments
High fluid velocities and associated shear stresses are typically encountered in oil and gas transportation pipelines and can lead to severe corrosion attack. One way to mitigate corrosion is by injection of corrosion inhibitors, which need to be effective in this challenging environment. The main objective of this research was to evaluate the performance of different commercial inhibitors with emphasis on the impact of high flow velocities under highly corrosive conditions. The importance of inhibitor concentration and effect of acetic acid was also investigated. Experiments were performed in a mid-scale flow loop, called thin channel flow cell, that enables the simulation of high flow velocities (high shear stress). Linear polarization resistance and weight loss measurements were performed to assess the inhibitors ability to decrease the general corrosion rate, while scanning electron microscopy was used for surface analysis. The occurrence of localized corrosion was evaluated by means of profilometry analysis. All the inhibitors tested showed excellent inhibition properties for general corrosion. However, localized corrosion as high as 100 mm/y was observed in some cases.
Top of the Line Corrosion in Presence of Acetic Acid and Carbon Dioxide
This paper deals with the phenomena of corrosion by acetic acid and carbon dioxide at the top of a horizontal pipeline under dewing conditions. The effect of different parameters known to influence the Top of the Line Corrosion (TLC), such as the condensation rate and the bulk temperature is studied. The free acetic acid concentration varies from 0 to 1000 ppm, the bulk temperature, is set mainly at 70C, the condensation rate is varied while the partial pressure of carbon dioxide and the gas velocity are set at a fixed value. The presence of acetic acid increases the corrosion rate both at the top and at the bottom of the line in different ways. The condensation rate influences strongly the top of the line corrosion when it has a small influence at the bottom. Evidences of localized corrosion are found at the bottom of the line. The corrosion at the top is uniform in the experiments conducted.