Unveiling the effect of polymer on pipeline corrosion

This study unveiled the corrosion modification potential of an enhanced oil recovery polymer on flowline material in different saline environments. Polymers such as xanthan gum are usually used to control the mobility of the displacing fluid during flooding process to achieve better sweep efficiency. These polymers and brines are normally transported through flowlines into and from reservoirs, but their effect on flowline materials is not known. The weight loss method was used to study the corrosion rates of mild steel of known weights that were exposed to 0%, 10%, 50%, and 100% formation brine environments and varied concentrations (0.5%, 1%, 3%, and 5%) of xanthan gum for a total period of 432 hours. The results showed that the corrosion rate of mild steel increases with increase in exposure time, but the use of xanthan gum generally reduced the corrosion rates. Also, the corrosion rate of mild steel reduces with an increase in the concentrations of xanthan gum. Furthermore, higher corrosion inhibition efficiencies (>70%) were observed in 10% formation brine environment and the effective corrosion inhibition concentration of xanthan gum was found to be 1 wt.% in all saline environments investigated. Conclusively, from the results of this study, it is evident that the application of xanthan gum polymer commonly used in the enhanced oil recovery process has the potential to reduce the corrosion rate of mild steel in saline environments. The result of this study is significant for the design of polymer-enhanced oil recovery operations.