Compositional model improves gas-lift optimization for Iranian oil field

A simulation with a compositional model improved the accuracy when compared with a black-oil model for predicting the performance of gas-lift wells in the Aghajari oil field in Iran. The Marun oil field gas compressor station supplies the lift gas, which is drier and has a lower molecular weight than the gas from the Aghajari field separators. These differences in gas cause inconsistencies in black-oil model calculations. The black-oil method is fast but not accurate when one must take into account compositional differences. The study evaluated the gas-lift system with black oil and compositional models combined with multiphase flow correlations. The compositional modeling employs the Peng-Robinson equation of state (PR EOS) for rigorous thermodynamic and physical properties evaluation.