Viscosity-dependent empirical formula for electrical conductivity of H₂O-NaCl fluids at elevated temperatures and high salinity

This study proposes a new viscosity-dependent empirical model to calculate the electrical conductivity of H₂O-NaCl fluids at elevated-temperature and high-salinity conditions. The proposed model is developed based on the experimental data of Bannard (1975), which covers a wide range of pressure, temperature, and salinity conditions, i.e., pressures up to 200 MPa, temperatures up to c.a. 525 ^∘C, and NaCl concentrations from 0.06 to ca. 25 wt% NaCl. To the author's knowledge, this is the first model which is fully consistent with the experimental data of Bannard (1975). A comparison study with existing conductivity models showed that the proposed model can predict the conductivity of H₂O-NaCl fluids with higher accuracy particularly at temperatures above 200 ^∘C. On the other hand, detailed verification of the proposed model indicated that extrapolation of the proposed model to the low fluid density conditions (< 400 kg/cm³) may produce large errors (> 30%). Furthermore, we discussed pressure- and salinity-dependence of the fluid conductivity at elevated temperatures, as well as the bulk property of the two-phase (vapor-liquid) fluids, using the proposed model.