The Gibbs-Helmholtz constrained (GHC) equation of state (Lucia, 2010; Lucia et al., 2012) is a new equation of state that uses molecular scale information and a novel up-scaling equation to estimate the attraction parameter in the Soave-Redlich-Kwong equation of state (Soave, 1972). Recently, a general purpose modeling framework for simultaneous phase and chemical reaction equilibrium has been developed around the GHC equation of state for systems containing any number of ions (Lucia et al., 2014). This new modeling framework permits molecular salt (or mineral) deposition/dissolution, has been implemented within a FORTRAN library called GFLASH, and has been interfaced with the Automatic Differentiation General Purpose Research Simulator (AD-GPRS) (Voskov and Zhou, 2012).
In this talk, a number of isothermal, isobaric (TP) flash solutions and phase diagrams for systems containing multiple dissolved ions will be presented and validated using comparisons to experimental data from the open literature. Finally, numerical results from fully compositional simulations of CO2 injection into the Johansen formation with multiple fluid phases and dissolution/precipitation of multiple salt phases will be presented and discussed.