(425c) Modeling Barite Precipitation in High Temperature Systems Based on Molecular Statistical Thermodynamics Model

A molecular statistical thermodynamic (MST)-based model has been implemented to reliably predict the solubility of barium sulfate for a range of thermodynamic region poorly described using the conventional Helgeson-Kirkham-Flowers model for ions and neutral molecules (ion pairs) in water. The experimental solubility data of barium sulfate compare well with both MST and HKF predicted values at temperatures below 300 ^oC. As the temperature increases toward and beyond the critical point of pure water, the HKF model loses accuracy while our model consistently shows reasonable agreement with the experimental data. This trend shows the validity of the MST model to predict solubility limits hence the mineral scale precipitation in high-temperatures systems typically encountered in high-enthalpy geothermal systems and ultra-deep oil reservoirs.