Computer-controlled, portable pulsed NMR instrument and method of use wherein a DC magnetic field gradient is artificially introduced

摘要

In accordance with the present invention, fluid-flow properties of a rock sample based on NMR response of the hydrogen nuclei of interstitial fluids within the pore space of such sample, can be swiftly and accurately achieved using a computer-controlled, portable NMR instrument. The inherent instrument inadequacy of phase background jitter is controllably augmented by generating (via a computer-initiated DC source current) a DC magnetic field gradient across the sample. Result: A DC field inhomogeneity of D gauss is discontinuously introduced to the steady DC field to maintain high data-throughput efficiency, i.e., the number of NMR responses performed per unit time. And, even though the instrument is placed at field sites away from the usual processing center, quick analysis of rock samples as during the drilling of a well, still occurs.