1. n. [Formation Evaluation]

A technique for cleaning core samples in which the water fraction is removed by distillation and the oil fraction is extracted using solvents. Cleaning is done with either the Soxhlet or, when fluid saturation measurements are required, the Dean-Stark apparatus. Different solvents are used depending on the type of fluids and rock, the most common ones being toluene, methanol, xylene, and chloroform. Several solvents may be used in sequence.

See related terms: centrifuge,  Dean-Stark extraction