ROCK POROSITY DETERMINATIONS USING PARTICLE DENSITIES MEASURED IN DIFFERENT FLUIDS

Rock porosity, when calculated from measurements of bulk and particle rock density, is found to depend on the method used to determine these densities. The particle density, which is found experimentally, varie s with the immersion fluid used; hence, the porosity determined depend s on it, too. Organic fluids are recommended in standards for describi ng particle density for special applications; however water is general ly considered to be virtually inert when in contact with inorganic par ticles, particularly if the particles are composed of silicates. Thus, the results of measurements made using water as the immersion liquid are not considered to have been measurably affected by water. This pap er shows that water does, in fact, alter measurably the value of silic ate particle density obtained compared with measurements made using an organic fluid, viz., n-heptane. Explanations for this finding are und er further consideration.