Desenvolvimento de metodologia para cálculo de formação de precipitado de sulfato de bário

Abstract

One of the methods of oil recovery is the injection of sea water, which, despite its benefits, can trigger the formation of scale, an operational problem that obstructs, totally or partially, the flow channels of the equipment present in the well, generating costs related to interventions, replacement of equipment and contracting of services. Precipitation is a consequence of temperature and pressure variations resulting from the exploitation of the reservoir or from the mixture of incompatible species originating from the injection water and the conata water, promoting a thermodynamic state of imbalance of the confined fluids in the reservoir. Among the types of possible incrustations, there is the inorganic salt of barium sulfate, which has less solubility in water and whose removal is more complex. Thus, it is of paramount importance for the oil industry to predict the amount of precipitate and estimate the severity of the scale. Thus, the objective was to develop a methodology for calculating the solubility of barium sulfate through the use of the equilibrium constant, performing a thermodynamic study involving the formation and precipitation of this salt in oil production wells, visualizing the joint effect of temperature and pressure in this phenomenon. The result is a chart composed of these values, representing the maximum solubility limit of barium sulphate, and which allows us to visualize the appropriate conditions to avoid the formation of a precipitate of barium sulphate.