ntu meaning in oil and gas

nephelometric turbidity unit

A nephelometer is an instrument for measuring suspended particulates in a liquid. It does so by employing a light beam (source beam) and a light detector set to one side (usually 90°) of the source beam. Particle density is then a function of the light reflected into the detector from the particles. To some extent, how much light reflects for a given density of particules is dependent upon properties of the particles such as their shape, colour, and reflectivity. <p> The more popular term for this instrument in water quality testing is a turbidimeter. However, there can be differences between models of turbidimeters, depending upon the arrangement (geometry) of the source beam and the detector. A nephelometric turbidimeter always monitors light reflected off the particles and not attenuation due to cloudiness. The units of turbidity from a calibrated nephelometer are called Nephelometric Turbidity Units (NTU).<p> An ntu is thus a measure of the "cleanliness" of a fluid, for our purposes generally completion brine.