Determination of Fluid Saturation in Porous Media by a Radio-Frequency Method

Abstract

A KNOWLEDGE of fluid saturation at any one cross-section is very often required when studying fluid behaviour in porous media. Investigators measuring this have employed a variety of techniques including resistivity methods^1,2, radioactive tagging of a fluid³, X-rays⁴, and light absorption⁵. Very often it is required to know the extent of saturation of water or a water solution in a porous medium. Since water has a high dielectric constant, it has seemed worth while to consider a method which is dependent on this fact, and which would be used primarily for water or water solution. The technique proposed here has its origins in high-frequency titrations^6,7, where a high-frequency signal is fed into an electrode or coil on the tit rat ion cell. Changes in composition during the course of a titration are then measured in terms of change in current or voltage of the plate or grid of the oscillator valve or change in frequency of the oscillator. A change in degree of saturation in a porous medium will produce a similar loading effect in an oscillator as a high-frequency titration, and consequently, a similar method of detection may be employed.