Effect of temperature and fluid speed on the corrosion behavior of carbon steel pipeline in Qatari oilfield produced water

Abstract

Metals integrity, such as carbon steel used in pipeline network can be seriously damaged by produced water causing serious corrosion problems. This can result in significant threats to safe operation of the oilfield facilities and leads to considerable economic losses. In this study, the effect of produced water from the North oilfield of Ras Laffan in Qatar on corrosion and scaling of carbon steel is investigated using electrochemical methods. The specimen rotation speed ranged from 0 to 2 m/s and temperature between 20 and 60 C were used as test parameters for the study. X-ray power diffractometer (XRD) and scanning electron microscopy (SEM) techniques were employed in the analysis of the corroded steel samples. It was found that the corrosion rate increased with increasing temperature and specimen rotation speed. These results also showed that the steel reacted with the corrosive ions at the early stage of its exposure to the produced water leading to the formation of corrosion products on the steel surface in which CaCO3 scale layer were deposited on the surface of the specimen as loose products due to the presence of large amounts of Ca2 + and HCO3- ions contained in the Rass Lafan oilfield produced water. More so, pitting and cracks were observed on the steel surface which increased as the temperature and specimen rotation speeds were increased, suggesting localized corrosion mechanism.