The initial saturation state of a rock directly affects the reliability of petrophysical measurements, since small variations in fluid distribution can influence parameters derived from water-based measurements, such as permeability and capillary pressure. This thesis compares three procedures for saturating sandstone core plugs: a vacuum–pressure sequence performed with a Vinci saturator, a controlled-rate injection using a threshold-pressure apparatus, and a continuous vacuum method implemented in a custom chamber. All techniques were applied to the same plugs spanning low, intermediate and high permeability ranges, and water uptake was quantified gravimetrically, with pressure and flow data from the injection method used only to verify stable hydraulic conditions.