SRK Equation Of State Research Articles

Thermodynamics of petroleum mixtures containing heavy hydrocarbons. 2. Flash and PVT calculations with the SRK equation of state

The oil and gas mixtures described in part 1 of this series are subjected to three PVT experiments commonly performed on oil and gas mixtures: constant mass expansion, differential liberation, and constant volume depletion. In addition, P,T flashes at separator conditions are determined experimentally. These experimental results are simulated with the SRK equation of state plus various correlations for the liquid-phase molar volumes. It is found that the hydrocarbon characterization methods presented in part 1 give satisfactory simulations of the P,T flash and PVT data. The most suitable liquid-phase molar volume correlations are the Standing-Katz and Alani-Kennedy correlations.

SRK-EOS calculation for crude oils

Analytical data for North Sea oils and gas condensates have been measured. The data include GC and TBP analyses and measurements of molecular weights, specific gravities, and PNA-distributions of most TBP-fractions. For each mixture, a few dew and bubble points have been measured, and in addition PVT-data and separator flash compositions have been determined. These experimental results are simulated using the SRK equation of state and a suitable characterization procedure based on the analytical information. It is shown that accurate predictions of the phase behavior can be achieved using only a total of six hydrocarbon fractions. No “matching” or “tuning” to experimental phase equilibrium or PVT data is needed.