Patent ID: 8115481

Claim:
A method for analytically separating properties of hydrocarbon materials from properties of non-hydrocarbon materials in an earth formation penetrated by a borehole using NMR relaxation times, the method comprising: performing a first nuclear magnetic resonance (NMR) measurement for sodium-23 ( 23 Na) at a resonance frequency in a first sensitive volume in the earth formation outside of the borehole, using NMR relaxation times for the first sensitive volume that correlates to a relaxation time for the sodium-23 ( 23 Na), wherein the first sensitive volume has a homogeneous magnetic field having a magnetic field strength; performing a second NMR measurement for hydrogen ( 1 H) at another resonance frequency in a second sensitive volume in the earth formation outside of the borehole, using NMR relaxation times for the second sensitive volume that correlates to a relaxation time for the hydrogen ( 1 H), wherein the second sensitive volume has a magnetic field gradient having a maximum magnetic field strength that is less than the magnetic field strength of the homogeneous magnetic field of the sodium-23 ( 23 Na); wherein the first and second NMR measurements, respectively of sodium-23 ( 23 Na) and hydrogen ( 1 H), are performed with a magnet that comprises at least one of a barrel magnet, a bar magnet, and the combination of a barrel and bar magnet; and analytically separating the properties of the hydrocarbon materials from the properties of the non-hydrocarbon materials using the first sodium-23 ( 23 Na) NMR measurement and the second hydrogen ( 1 H), NMR measurement.