1. n. [Formation Evaluation]

A technique for measuring the effective porosity of a core sample by summing the volumes of the fluids recovered from it. The volumes of the gas, oil and water in the sample usually are determined by the retort method, which also determines the bulk volume. The porosity is then the ratio of the total fluid volume to the bulk volume.

See: Boyle's Law Double Cell,  Boyle's Law Single Cell,  buoyancy,  core plug,  liquid saturation method,  mercury displacement method,  porosimeter,  retort method,  routine core analysis