Abstract
To mitigate the effect of highly corrosive water injection media (aquifer water), which has a very high total dissolve solid (TDS) value with high oxidizing agents, internal fusion bonded epoxy (FBE) coatings, in addition to corrosion inhibitor were used to provide internal corrosion protection of water injection plant piping. A year after start-up of water injection plant (WIP), the plant piping started experiencing internal FBE coating failure. The failed coatings were found at the strainer and recycle valve after causing high differential pressure during operation. Seven different types of failed coating films were collected from the suction strainer. A comprehensive failure investigation was conducted to determine the root cause of the failure, and identify the source of various failed coating films found. Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray Spectroscopy (EDS), X-ray diffraction (XRD) and differential scanning calorimetry (DSC), were used to identify the type of coating and its manufacture. A robotic video crawler (RVC) was used to inspect the internal coating condition for the piping system. The effect of corrosion inhibitor injection and plant operating parameters on the coatings were all reviewed and evaluated. It was concluded that improper coating application was the root cause of the failure.
