Patent ID: 7164266

Claim:
A nuclear magnetic resonance logging system comprising a conductive permanent magnet functioning with minimized induced eddy currents therein, the system comprising: (a) a tool; (b) conveyance means with a downhole end and an uphole end wherein said downhole end is operationally attached to said tool; (c) driver means disposed at the surface of the earth and operationally attached to said uphole end of said conveyance means; and (d) a magnet-coil assembly disposed within said tool and comprising (i) said conductive permanent magnet producing a static magnetic field, (ii) at least one RF coil oriented to produce a RF magnetic field essentially perpendicular to said static magnetic field, and (iii) soft ferrite elements so disposed with said at least one RF coil and said conductive permanent magnetic to minimize said eddy currents induced within said conductive permanent magnet by said RF magnetic field.