(153e) Molecular Simulation of Double Retrograde Vaporization

Liquid dropout due to retrograde condensation during production of rich natural gas leaves valuable condensate fluids in the oil reservoirs, leading to significant loss of well productivity and potentially unfeasible recoveries. Thus, accurate modeling of fluid properties across a wide range of conditions is vital for the design and optimization of enhanced oil and gas recovery processes. In this work, Gibbs-ensemble Monte Carlo simulations using transferable force fields are applied to investigate double retrograde vaporization in fluid mixtures near the critical point of the lower-boiling compound. Here, methane/n-butane, carbon dioxide/n-alkane, and carbon dioxide/(benzene or toluene) mixtures are discussed. The molecular simulations allow one to provide molecular-level understanding of the phase behavior of these mixtures at relevant reservoir operation conditions.