Maleic acid based scale inhibitors for calcium sulfate scale inhibition in high temperature application

In anhydrite rich reservoir rock, calcium sulfate is one of the dominant scale components which unlike carbonate scale are not easily removable by acid or dissolver treatment. To inhibit calcium sulfate scale formation in high temperature producing brine water systems, maleic acid-acrylic acid and maleic acid-acrylamide copolymers of appropriate molecular weight were synthesized and characterized and inhibition efficiency of the copolymers was tested at static and dynamic conditions. Their iron dispersing ability measured through UV spectroscopy is found to be excellent and their biocidal activity investigated through agar culture and serial dilution technique is almost insignificant. XRD and SEM analyses proved the morphological changes of the calcium sulphate scale due to strong inhibition action.