This paper presents new coupled three-phase relative permeability and capillary pressures models for implementation in a four-phase flow compositional EOS simulator. Identification of hydrocarbon and aqueous phases based on their molar Gibbs free energy is a key feature of the new model. Instead of using phase labels (gas/oil/solvent/aqueous) to define parameters such as relative permeability endpoints, residual saturations and exponents, the parameters are continuously interpolated between reference values using the Gibbs free energy of each phase at each time step. Models independent of phase label have many advantages in terms of both numerical stability and physical consistency. The models integrate and unify relevant physical parameters including trapping number and hysteresis into one rigorous algorithm for application in numerical reservoir simulators. The robustness of the new models is demonstrated with simulations of miscible WAG and solvent stimulation to remove condensate and/or water blocks in both conventional and unconventional formations.

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