This paper presents results of some recent laboratory study on barium sulphate scale inhibition in oilfield brines and investigation of several factors potentially affecting scale inhibition efficiency, In addition to well known mechanisms of scale nucleation inhibition and crystal growth retardation, dispersion/anti-conglomeration appears to be a significant
inhibition mechanism associated with some scale inhibitors, which may play an important role in a dynamic flowing system. The contamination of a brine by an organic chelating agent such as EDTA or citric acid did not, in this study, show any sigtilcant effect on the barium sulphate inhibition efficiency of any of the three generically different scale inhibitors included. Experiments show that, in a properly enclosed system, the pH of an oilfield brine even with hydrogen bicarbonate presence can be sufficiently buffered with acetic acid. These new results are believed to be useful
in evaluating/selecting scale inhibitors and improving barium sulphate scale inhibition test methods.
Keywords: scale, barium sulphate, oilfield brines, inhibition mechanism inhibition efficiency, dispersion, chelants, pH control.