The SAFT-VR equation of state is combined with a semi-continuous thermodynamic approach to model several synthetic and crude oil systems. In our approach, the oil fractions are defined by a continuous distribution that is then represented as discrete pseudo-components using the Gaussian quadrature method. The SAFT-VR parameters for the pseudo-components are obtained from simple linear relationships that were defined in earlier work, which allows the approach to be easily applied to undefined oil systems. Good agreement between the theoretical predictions and experimental data is obtained for bubble point pressure calculations of several gas condensates and the solubility of gases such as methane, ethane, and carbon dioxide in several crude oils.