Near-Critical Phase Behavior of Reservoir Fluids Using Equations of State

SUMMARY Phase behavior prediction by an equation of state in the near-critical region shows extreme sensitivity to the binary interaction coefficients. For binary mixtures, these coefficients have a systematic decreasing trend as the critical point is approached. Such a trend can be used to calculate the phase behavior of binary mixtures in the critical region. For complex near-critical reservoir fluids, a variable interaction coefficient may not provide satisfactory results. A fixed reduction of the binary interaction coefficients is a simple practical step towards EOS prediction of phase behavior of complex reservoir fluids.