The methods that are used to measure values of original rock saturation can be classified to two classes: Evaporation of the fluids in the rock and Leaching out the fluids in the rock by extraction with a solvent.
The extraction method is based on the extracting with a solvent during a distillation process. The core is placed and a vapor of solvent rises through the core and is condensed to reflux back over the core. This process leaches out oil and water in the core. The water and extracting fluid are condensed and collect in a graduated receiving tube.