Viscosity Models and Effects of Dissolved CO2

A comprehensive study is carried out on viscosity modeling for the geologic sequestration of CO2 in the pressure and temperature range of 1-600 bar and 20-105 degrees C, respectively. For the liquid phase, we present viscosity models for pure water (H2O), brine (H2O + NaCl), H2O + CO2, H2O + NaCl + CO2, and typical seawater compositions. In each case, we attempted to develop very accurate formulations having fewer parameters than existing models. Because of their simpler forms these also help obtain some computational speedup. The effects of dissolved CO2 are studied extensively. For liquid phase viscosity calculations we have found that, if the presence of CO2 is neglected, deviations can be even 38% when the solution is CO2 saturated and, with 2% (by weight) CO2 dissolution, the difference is 0.6-8%.