Effect of Additives on Phase Diagrams: Normal Butane Added to Condensate-natural Gas System.
Producers Monthly 1968 Dec; 32(12):8-15
The effect on phase-boundary pressures of a related series of condensate mixtures of additions of normal butane was determined with a windowed pvt cell. The investigation was conducted at pressures up to 5,000 psia and at temperatures in the range of 70 deg to 310 deg f. Relationship of the critical state to changing compositions was evaluated. The fluids were a mixture of intermediate hydrocarbons and selected distillation cuts from a field condensate combined with mole fractions of natural gas in the range 0.800 to 0.933. The data were subjected to statistical analysis using a computing program that provided a polynomial for interpreting the results. The polynomial yields phase-boundary pressures, and independent variables are temperature, natural gas content, and mole fractions of normal butane additive. A method is described for approximating such a polynomial before measurements are complete using a mathematical model that requires more measurements than are available.
Producers Monthly, V. 32, No. 12, December 1968, PP. 8-15