A long-term effective solid capsule with matrix-type structure for the anticorrosion in oil and gas fields

The oil and gas industry frequently uses liquid corrosion inhibitors to reduce equipment and pipeline corrosion. However, this approach requires frequent additions, which are costly in terms of labor and materials. Solid corrosion inhibitor capsules (SCICs) have become an optimal alternative, as they provide long-term corrosion protection. However, the current encapsulation materials need to be modified for improving encapsulation capability. In this study, lauryl acrylate (LA) was grafted onto Ethylene-vinyl-acetates (EVA) to reduce its crystallinity and increase the interface force between EVA and oleic imidazoline (OIM). OIM was then encapsulated using the grafted EVA (EVA-g-LA) to form matrix-type solid capsules that possess the high encapsulation efficiency and long service life. The analysis with a UV–Vis spectrophotometer revealed that OIM had a stable release process from the SCIC matrix. Over a period of 91 days, the released OIM still had a high corrosion inhibition efficiency towards N80 steel (>80%). Using the prepared SCIC can reduce annual anticorrosion costs in oil and gas fields by 70%.