The oil and water content represent the fraction of the effective porosity occupied by the specific fluid in a core sample. They are measured by Dean-Stark methodology. According to the procedure oil is removed from the sample by extraction, i.e. dissolved in a suitable solvent, most commonly toluene, xylene, naphtha or solvent mixtures of selected composition. The mixture of core’s water and solvents’ vapors is evaporated by distillation and further condensed in a suitable volumetric tube, where water is separated gravimetrically and quantitatively determined.