Study of BaSO₄ formation kinetics and inhibition effect of polyphosphino-carboxylic acid (PPCA) with Synchrotron X-Ray Diffraction (SXRD)

Precipitation of barium sulphate from aqueous supersaturated solutions is one of the most well known problems in the oil industry. Precipitation of barite and other insoluble scale types (metal sulphates, calcium carbonate and silicates) propagate to undesirable formations, which adhere strongly in production tubing and in equipment parts. Formation of BaSO₄ lead to a decrease in the performance of the petroleum facilities and to inevitable damage in the oil industry. Barium sulphate is one of the most insoluble types of inorganic scale. It resists many chemical methods of removal. Inhibition of barium sulphate by chemicals is generally recognized as the most appropriate approach for flow assurance. In this study Synchrotron X-Ray Diffraction was used to investigate the kinetics of barium sulphate formed on stainless steel surface at two different temperatures. For the first time SXRD measurements of BaSO₄ formed in the presence of foreign ions (Sr²⁺, Ca²⁺ etc) are presented. The in-situ measurements allowed the assessment of the crystallographic nature of the formed scale and the probation into the precipitation mechanisms. Additionally this study focused on the effect of PPCA on the barium sulphate precipitation. PPCA was examined for its inhibition action in two concentrations at both temperatures. The formed barite crystal faces after the treatment with PPCA were recorded. Copyright 2008, Society of Petroieum Engineers.