1. n. [Formation Evaluation]
The fraction of water in a given pore space in the flushed zone. It is expressed in volume/volume, percent or saturation units and is given the symbol Sxo. Unless otherwise stated, the pore space concerned is usually the effective porosity. If the pore space concerned is the total porosity, the saturation is more correctly known as the total flushed-zone water saturation; or if it is the effective porosity, the effective flushed-zone water saturation.