Density
The density at all points of a homogeneous object equals its total mass divided by its total volume. The mass is normally measured with a scale or balance; the volume may be measured directly (from the geometry of the object) or by the displacement of a fluid. To determine the density of a liquid or a gas, a hydrometer, a dasymeter or a Coriolis flow meter may be used, respectively. Similarly, hydrostatic weighing uses the displacement of water due to a submerged object to determine the density of the object.
Density logging
Assuming that the measured bulk density (formula_1) only depends on matrix density (formula_8) and fluid density (formula_9), and that these values are known along the wellbore, porosity (formula_10) can be inferred by the formula