TY - JOUR
T1 - Characteristics of scales and their impacts on under‐deposit corrosion in an oil production well
AU - Yang, Yan
AU - Luo, Xuan
AU - Elsayed, Yousr E. A. N.
AU - Hong, Chuanshi
AU - Yadav, Abhijeet
AU - Rogowska, Magdalena
AU - Ambat, Rajan
PY - 2021
Y1 - 2021
N2 - This study examined the composition and characteristics of scales formed at different depths in an oil production well, which had developed over years of well operation, workovers, and interventions, by the combined use of optical microscopy, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, transmission electron microscopy, and X‐ray diffraction. The iron‐rich scales consist of several mineral phases, including a dominant portion of akagneite and hibbingite, some barite, silicon dioxide, copper sulfide, and small amounts of iron oxide and calcium carbonate. The scales typically have a layered structure consisting of five to six distinct layers, which impacts steel corrosion processes. The type of corrosion beneath the scale surface was found to be diversified. Pitting morphology corresponding to different stages in the development of scales was observed. The relation between pitting density and the extent of corrosion was analyzed. The effects of environmental factors, including calcium, chlorine, oxygen content, steel microstructure, and multiphase flow, on scale formation and corrosion mechanisms, were discussed. The results provide important insights into the formation of scales and the under‐deposit corrosion processes in the oil production tubes.
AB - This study examined the composition and characteristics of scales formed at different depths in an oil production well, which had developed over years of well operation, workovers, and interventions, by the combined use of optical microscopy, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, transmission electron microscopy, and X‐ray diffraction. The iron‐rich scales consist of several mineral phases, including a dominant portion of akagneite and hibbingite, some barite, silicon dioxide, copper sulfide, and small amounts of iron oxide and calcium carbonate. The scales typically have a layered structure consisting of five to six distinct layers, which impacts steel corrosion processes. The type of corrosion beneath the scale surface was found to be diversified. Pitting morphology corresponding to different stages in the development of scales was observed. The relation between pitting density and the extent of corrosion was analyzed. The effects of environmental factors, including calcium, chlorine, oxygen content, steel microstructure, and multiphase flow, on scale formation and corrosion mechanisms, were discussed. The results provide important insights into the formation of scales and the under‐deposit corrosion processes in the oil production tubes.
KW - Amorphous
KW - Corrosion assessment
KW - Pipelines security
KW - Pitting
KW - Scale deposit
U2 - 10.1002/maco.202012095
DO - 10.1002/maco.202012095
M3 - Journal article
VL - 72
SP - 1051
EP - 1064
JO - Materials and Corrosion - Werkstoffe und Korrosion
JF - Materials and Corrosion - Werkstoffe und Korrosion
SN - 0947-5117
IS - 6
ER -