Part 2. Special Issues in Intellectual Systems Theory

Reconciliation of Wilson formulas and the equation of state for calculating the phase equilibrium of oil and gas

E. V. Koldoba

Lomonosov Moscow State University, Faculty of Mechanics and Mathematics

Abstract: Iterative methods are used to compute phase equilibrium in multicomponent hydrocarbon solutions. Wilson’s formula is taken to calculate initial approximations, and the equation of state is taken to calculate chemical potentials or volatility. The paper proposes a method for adjusting Wilson’s formula to the equation of state used. It is shown that the consistent coeficients for heavy components are greater than for light ones. The approach allows one to construct a thermodynamically consistent system and eliminate some non-physical solutions and numerical instabilities.

Keywords: equations of state, Wilson’s formula, compution of phase equilibrium, multicomponent solutions, oil, numerical modeling