This paper builds on the evidence for the optimum dose of organic film-forming corrosion inhibitor (FCCI) being at the critical micelle concentration (CMC) of the surfactant components, and the concept of micelle detection as a tool for understanding the effectiveness of the inhibitor dose in the field. It extends the underlying principles from laboratory testing, to the rapid analysis of field fluids and explores the different results available from alternative instrumentation. An inhibitor optimisation trial was undertaken on an offshore oil production platform for protection of a subsea pipeline used to tie back wells 10 miles from the platform. Two micelle detection devices were used, both primarily using fluorescence detection - a simple handheld device for offshore testing and a more complex device used for testing shipped samples in an onshore lab (CoMic). Electrochemical corrosion monitoring was also used to analyse the produced fluids as the inhibitor dose was varied from zero to 200% of the estimated optimum dose. Results were clouded by operational issues outside the control of the experiment but interpretation of the whole suggested that the offshore portable micelle analysis was overcome by large quantities of dispersed oil, which masked the optical process. However the lab CoMic testing gave some promising results, demonstrating a correlation between increased micelle levels and high inhibitor dose and suggesting that the original dose was sub-optimal. A further experiment was conducted on samples arriving at a receiving terminal via an offshore transportation pipeline. Water samples water analysed as they arrived at the facility and CoMic analysis confirmed optimum inhibition with only slight variability observed over the duration of the trial Analysis of water associated with pigging revealed a high micelle population, suggesting that the action of the pigs strips the corrosion inhibitor film from the pipeline walls. These experiments supported the need to use the more complex instrument to be able to detect micelles in very impure systems. Field deployment of the CoMic technology is now underway.
Micelle detection for optimising corrosion inhibitor dose on an offshore platform
Mizellenerfassung zur Optimierung der Korrosionsinhibitordosierung auf einer Offshore-Produktionsplattform
Corrosion Management ; 109 ; 14-19
2012
6 Seiten, 8 Bilder, 11 Quellen
Article (Journal)
English
Dosierung , Effizienz , elektrochemische Korrosion , Erfassung , Filmbildung , Fluoreszenzmessung , Handgerät , Inhibitor (Hemmstoff) , Korrosionsinhibitor , Korrosionsschutz , Labortest , Mizelle , Mizellenkonzentration , Offshore-Plattform , Ölpipeline , Optimierungsverfahren , Schnelltest , Unterwasserrohrleitung