| dc.description.abstract | Corrosion poses significant economic, safety, and environmental challenges in the oil and gas industry, necessitating effective corrosion inhibition strategies. Chemical inhibitors offer a cost-effective solution, yet selecting the appropriate formulation remains complex due to diverse field compositions and metallurgies. Film-forming inhibitors such as phosphate esters, imidazolines, and quaternary ammonium compounds along with sulfur compounds are widely used to combat CO2 and H2S corrosion. However, the environmental and health impacts of using sulfur compounds warrant investigation into alternative formulations.
This study aims to assess the synergistic effect of H2S in the absence of sulfur compounds on C1018 carbon steel corrosion. The corrosion behavior of C1018 carbon steel in 3% NaCl brine with either pure CO2 or CO2/H2S was evaluated using the static bubble test and dynamic rotating cage autoclave experiment at 60 °C and 20 °C to investigate the synergistic effect of H2S on carbon steel pipes. The influence of pH, temperature, and H2S concentration on corrosion inhibitor performance was reviewed. Results indicate that phosphate esters, imidazoline, and quaternary amines exhibit higher inhibition efficiency in CO2/H2S environments without sulfur compounds. Notably, even at lower H2S concentrations, imidazolines, and quaternary amines demonstrate stable inhibitory rates. In a field case study, the corrosion rate of an imidazoline corrosion inhibitor was measured. When exposed to 0.035% H2S, the average corrosion rate was determined to be 0.0365 mm/y. This rate was lower than the corrosion rate observed when both a sulfur compound and 0.035% H2S were present, which was 0.08 mm/y. Eliminating sulfur compounds from corrosion inhibitor formulations offers environmental benefits and mitigates health risks. The findings underscore the importance of understanding chemistry and complex chemical interactions in corrosion environments and should be investigated further to optimize the inhibitor formulations for enhanced performance and reduced environmental impact. | |
