Downhole nuclear magnetic resonance (NMR) tool for one-dimensional NMR imaging

摘要

A nuclear magnetic resonance (NMR) tool includes an antenna assembly and a magnet assembly. The NMR tool also includes a motional sensor comprising at least one radio frequency (RF) antenna disposed about a tool axis and about at least a portion of the magnet assembly, in which the motional sensor is operable to generate readings for lateral motion of the antenna assembly and the magnet assembly. The at least one RF antenna has a soft magnetic core and a coil winding disposed around the soft magnetic core. The motional sensor can determine a one-dimensional NMR image indicating a lateral displacement of the NMR tool based on one or more spatial positions of NMR excitation volumes in the region of interest that correspond to respective excitation frequencies in the at least one RF antenna.