Abstract: Dispersion coefficients of fluids in porous media are determined by NMR spin echo techniques while the fluid is flowing through the porous medium.

Abstract: The pore size distribution and the distribution of fluid in a porous media, such as a reservoir rock formation, is determined by nuclear magnetic resonance spectrometry technique. A sequence of three radio frequency pulses is applied to a sample which is placed in a large static magnetic field. The resultant spin echo is measured and is utilized to determine the pore size distribution in the porous medium. If water is present in the sample, the sample is doped so as to substantially eliminate the nuclear magnetic resonance response of the hydrogen in water. The technique can be utilized to distinguish between hydrocarbon filled and water filled pores in the sample thus providing information concerning the fluid distribution in the sample.