(540c) Efficiencies and Performance of Commercial and New Oilfield Antiscalants for Calcium Carbonate Inhibition

Mineral scale formation, in particular calcium carbonate, continues to persistent across various industries ranging from oil and gas to desalination. Consequences of scale formation can be dramatic, and often leads to production shutdown. Antiscalants are widely used to inhibit scale formation within reservoirs, wellbore tubing and equipment, but according to literature their inhibitory ability remain limited and most often questionable. This study aimed to investigate the inhibition efficiency and performance characteristics of most common commercial and an in-house synthesized formulations. Seven antiscalants, four from different manufacturers and three in-house formulations produced via grafting polymerization at various concentrations were tested in batch experiments for the inhibition of calcium carbonate. Positive compatibility test results were achieved prior to testing by mixing two incompatible cationic and anionic brines. The inhibition efficiency was calculated by the amount of calcium ions left in solution that was determined by ICP-OES. Several observations were highlighted from the study findings. First, the inhibition efficiency appeared to increase with increasing temperature and pH after 16 hours of reaction time. Second, the inhibition efficiencies were higher at lower inhibitors’ dosages. Finally, the commercial antiscalants appeared to reach a plateau of about 68% efficiency at brine solutions salt concentrations beyond 85,000 ppm. Two of the inhouse formulations resulted in 83% and 87% inhibition efficiencies at brine concentrations up to 200,000 ppm. The third in-house formulation showed a much lower efficiency at brine salt concentrations below 85,000 ppm, but exhibited an interesting and promising corrosion inhibition of carbon steel.