Laboratory Evaluation and Mechanistic Understanding of the Impact of Ferric Species on Oilfield Scale Inhibitor Performance

Abstract

Scale inhibitor chemicals are widely used in oilfield operations for mineral scale control. However, the presence of iron species in oilfield produced water can considerably impair the performance of scale inhibitors. To date, few studies have been conducted to experimentally investigate the mechanism of iron effect on scale inhibitors. Although Fe(II) is the major form of iron species in oilfield produced water, Fe(III) can be formed in produced waters due to oxidation of Fe(II). In this study, Fe(III) effect on various scale inhibitors was evaluated by examining the inhibitor performance to control barium sulfate (barite) scale formation. This study finds that Fe(III) can significantly impair the performance of both phosphonate and polymeric inhibitors with an iron concentration below 1 mg L–1. Moreover, the mechanism of the influence of Fe(III) on scale inhibitors was studied by investigating the adsorption capacity of ferric hydroxide solid of phosphonate scale inhibitor and also examining the efficac...