Design of a permanent magnet configuration for nuclear magnetic resonance logging

Nuclear magnetic resonance logging (NMRL) as one kind of oil- and gas- detecting logging tools has been widely applied to commercial logging, and the magnet of the sensor mainly adopts permanent magnet (PM) configuration. MRIL-Prime and Combinable MR sensor are typical examples of two logging modes for NMR logging. By comparing these two structures and analyzing the magnetic field performance in the detection region, an improved PM configuration is proposed. Through simulating the magnetic field distribution characteristics of the proposed magnet structure, the detecting depth and other technical specifications are summarized and its advantages are presented. According to the technical specifications, the proposed magnet structure is optimized.