On the dangers of “tuning” equation of state parameters

Abstract

Equations of state (EOS) are widely used in phase equilibrium calculations for mixtures containing undefined, heavy hydrocarbons. “Tuning” to measured PVT data is commonly used to find EOS parameters describing the thermodynamic properties of the mixtures in question. It is shown that “tuning” is unnecessary if the composition of the oil is properly described on the basis of an experimental compositional analysis and a newly developed characterization procedure. It is found that using EOS parameters “tuned” to one specific property yields unreliable predictions of other thermodynamic properties.