Viscosity of binary and multicomponent hydrocarbon fluids at high pressure and high temperature conditions: measurements and predictions

Viscosity estimation is essential for predicting flow regime and pressure drop through porous media and surface facilities. The experimental data of reservoir fluid viscosity especially at high pressure and high temperature condition are scarce and the need for knowledge of fluid property at this condition is increasing.

In this communication, new experimental viscosity measurements at high pressure and high temperature are reported for three binary hydrocarbon systems: methane/heptane, methane/decane and methane/toluene and three multi-component mixtures: a natural gas, a gas condensate and a synthetic volatile oil. The measurements were conducted in a HPHT PVT cell equipped with capillary tube at pressures ranging from 34.5–138 MPa and temperature up to 473.15 K.

The experimental data obtained for these mixtures have been used to evaluate the performance of different viscosity models. The investigated viscosity models are the Lohrenz–Bray–Clark (LBC) correlation, the Pedersen correlation and a modified LBC correlation. Although the viscosity models were applied at challenging HPHT conditions, the predictions were in reasonable agreement with experimental results. In general, the Pedersen method showed slightly better viscosity predictions for the mentioned hydrocarbon systems.