A method for evaluating saturation of a kerogen bearing subterranean formation includes obtaining conductivity and permittivity values of the formation and providing an effective medium model relating the conductivity and the permittivity to a water filled porosity of the formation and an effective aspect ratio of graphitic kerogen particulate in the formation. The obtained conductivity and the permittivity values are input into the model which is in turn processed to compute the water filled porosity. The method may further optionally include evaluating the water filled porosity to estimate a hydrocarbon producibility of the formation.