Heavy Oil Viscosity Modeling with Friction Theory

A new tuning method is proposed for the cubic equation-of-state-based friction theory viscosity model, which improves the viscosity prediction of heavy oils. With the existing tuning method, the error in viscosity prediction increases with increasing viscosity. Particularly, at pressures below the saturation pressure, the error keeps increasing as the pressure is farther away from the saturation pressure. With the proposed tuning method, whereas the single-phase error is almost the same, the two-phase error is approximately 1/3 the value of the error from the existing tuning method. Most importantly, the proposed tuning method successfully uses experimental viscosity data below the saturation pressure to reduce prediction errors.