Performance evaluation of glutaraldehyde-modified red onion skin extract as oilfield scale inhibitors

Scale deposition occurs due to changes during injection operations and the mixing of incompatible brines. Scale inhibitors are used to mitigate such occurrences. The inhibition efficiency of the glutaraldehyde-ROSE resin (ROG) was evaluated in synthetic brines containing CaSO4, BaSO4, and CaCO3 under static conditions according to NACE standard methods. The formulated scale inhibitor was compatible with the brine and thermally stable. The inhibition studies of ROG revealed optimal inhibition of 89% at 80 ppm and 58% at 100 ppm at 90 °C and 22 h, respectively, for BaSO4 and CaCO3 scales, while for CaSO4 scales, optimal inhibition of 67% was observed at 100 ppm, 71 °C, and 22 h. On comparison, the Commercial Scale Inhibitor (CSI) showed optimal inhibition of 97% at 100 ppm and 94% at 80 ppm at 71 °C and 22 h, respectively, for BaSO4 and CaSO4 scales, while for CaCO3 scales, optimal inhibition of 98% was observed at 80 ppm, 90 °C, and 22 h, respectively. This indicates that ROG efficiently mitigated the formation of CaSO4, BaSO4, and to some reasonable extent, CaCO3 scales, and its inhibition performance compared favorably with the CSI, thus unveiling its potential for consideration as a green oilfield scale inhibitor.