Summary
The speed and accuracy of compositional steamflood simulation were compared for four K-value calculation methods: the Antoine equation, table look-up, the Peng-Robinson equation of state (PR-EOS), and the Hong-Makhlouf modification of Wilson's equation. These methods were used with a compositional steamflood simulator to model light-oil steamfloods in three- and one-dimensional (3D and 1D) reservoir models. The results indicate that the table look-up and the Hong-Makhlouf modification of Wilson's equation are the most preferred methods to use in terms of both speed and accuracy of computation. While the PR-EOS method is the most accurate, it fails to converge for certain problems and takes twice as much computing time to do the same simulation as the other methods. The Antoine equation method is not accurate for high-volatility oils and hence should not be used for those oils.
This paper describes how the four methods are used in compositional steamflood simulation and discusses the advantages and disadvantages of each method.