Apparatus for nuclear magnetic resonance measuring while drilling a borehole

摘要

An apparatus for drilling a borehole and determining a parameter of interest of a formation surrounding a borehole during drilling. The apparatus comprises: (a) a longitudinal member (1) adapted to be conveyed in a borehole; and (b) a sensor assembly (54) including: (i) at least one NMR sensor for making NMR measurements relating to the parameter of interest, the sensor comprising a magnetic field generating assembly an RF antenna and a plurality of ferrite members (9,10) which couple with RF magnetic fields transmitted or received by the RF antenna; (ii) at least one clamping device (50) for engaging the borehole to clamp the sensor assembly to the borehole. The sensor assembly (54) is mounted via bearings (51) to the longitudinal member (1) so that the longitudinal member is free to move when the sensor assembly is engaged with the borehole. <IMAGE>