Patent ID: 6166543
Filing Date: 2000-12-26
Classification: G01N,G01V

Abstract:
An apparatus for measuring a nuclear magnetic resonance property of earth formations surrounding a borehole, without the application of RF pulses, comprising:a) means for applying a static magnetic field, Ba, in a volume of the formation which polarizes the nuclei of hydrogenous connate fluids within the formation;b) means for applying a static magnetic field, Bb, in the volume of the formation such that the static magnetic fields Ba, and Bb are substantially orthogonal in the volume of the formation and a change in polarity of the magnetic field Bb reverses the direction of precession thereby generating a gradient echo; and,c) means for detecting a signal induced in the formation after the nuclei begin to precess in the plane perpendicular to static magnetic field Bb wherein the precession frequency is proportional to the strength of static magnetic field Bb.