Validity of permeability prediction from NMR measurements

Low field nuclear relaxation measurements applied to porous media can provide a wide variety of information. One important use of NMR measurements in the petroleum industry is the estimation of in-situ permeability as a function of depth. Such information is not available from any other tool and is critical for oil recovery predictions. A large number of empirical relationships have been published without clear explanation of their physical origin. We present some understanding and illustration of the link between NMR relaxation measurements and permeability, which is useful to select the appropriate law as a function of the geological context.