Review of barium sulphate solubility measurements

Barium sulphate (BaSO4) scaling is a known issue but still an unresolved problem in the petroleum and geothermal industries. It can cause severe damage to the wellbore and surface facilities. Prevention of scale formation is the technically and economically advantageous solution to apply. This requires knowledge of the BaSO4 solubility in different brines at elevated pressure and temperature. This work aims at obtaining a comprehensive understanding of the status of BaSO4 solubility and to outline the way for future research. It provides a review of the experimental methods used to measure BaSO4 solubility, followed by a critical analysis of the general trends indicated by data from the different references. This information was used to draw recommendations for future studies regarding the measurement and calculation of BaSO4 solubility in brines. A comprehensive literature search was done to retrieve data on BaSO4 solubility in various electrolyte solutions. The findings were summarized and compared to phase equilibrium calculations performed using the Extended UNIQUAC model. Existing experimental data does not allow for unambiguous modelling of the solubility curve in such mixtures. This review also suggests there is only one reliable report of solubility measurements in pure water at temperatures greater than 100 °C. This points to the urgent need of extending the knowledge of the equilibrium properties of such solutions. Moreover, data on BaSO4 solubility in multicomponent aqueous solutions are limited to a few electrolytes and organic solvents. The addition of chlorides (NaCl, CaCl2, and MgCl2) into the solution increases BaSO4 solubility; whereas sulphates (Na2SO4) greatly reduce BaSO4 solubility due to a common ion effect. Development of a fine-tuned Extended UNIQUAC parameter set, with more ions, is challenging due to the low number of solubility measurements reported in the literature. The comparisons between experimental data and model clearly indicate that further experimental work is crucial to improve the accuracy of barite scale calculations. [Display omitted] •Barium sulphate solubility can be accurately calculated by the Extended UNIQUAC model in a wide range of environments.•Moderate amount of experimental data, but existing measurements are inconclusive.•Scaling prediction could be improved by further investigating solubility in a vast range of brines, temperatures, and pressures.