System and method for measuring borehole geometry while drilling

A system for determining a geometry of a borehole comprising:

• a nuclear magnetic resonance (NMR) logging device having a plurality of coils being configured to, when disposed in the borehole, acquire scans of the borehole using each of the plurality of coils, wherein the NMR logging device is configured to acquire the scans of the borehole using each of the plurality of coils by propagating RF energy at one or more frequencies with each coil, wherein each scan comprises a frequency range from approximately 100 kilohertz (kHz) to 2 megahertz (MHz);
• a processing module configured to determine a borehole wall distance between each coil of the NMR logging device and the borehole based at least partially on NMR measurements derived from the scans, and determine the geometry of the borehole based upon the determined borehole wall distance between each coil and the borehole wall;
• wherein the NMR logging tool is, for each coil, configured to obtain a porosity measurement value at each of a selected plurality of frequencies in the frequency range, wherein each of the plurality of selected frequencies corresponding to a different depth of investigation;
• and
• wherein the processing module is configured to identify a location of the borehole wall as corresponding to a depth of investigation where a decrease in porosity measurement values is observed, and determine the borehole wall distance between the coil and the borehole wall based on the identified location of the borehole wall.