Viscosity Models and Effects of Dissolved CO₂

A comprehensive study is carried out on viscosity modeling for the geologic sequestration of CO 2 in the pressure and temperature range of 1–600 bar and 20–105 °C, respectively. For the liquid phase, we present viscosity models for pure water (H 2 O), brine (H 2 O + NaCl), H 2 O + CO 2, H 2 O + NaCl + CO 2, 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 CO 2 are studied extensively. For liquid phase viscosity calculations we have found that, if the presence of CO 2 is neglected, deviations can be even 38% when the solution is CO 2 saturated and, with 2% (by weight) CO 2 dissolution, the difference is 0.6–8%.