Patent ID: 6018243
Filing Date: 2000-01-25
Classification: G01V

Abstract:
A nuclear magnetic resonance well logging apparatus, comprising:a magnet for inducing a static magnetic field in earth formations penetrated by a wellbore, said magnet polarized along a longitudinal axis of said apparatus, said static magnetic field having a sensitive volume within a substantially cylindrical sector on one side of the wellbore, said sector having a longitudinal axis substantially parallel to said longitudinal axis of the wellbore and a maximum longitudinal amplitude gradient related to an expected speed of motion of said apparatus along said wellbore;a transmitter for inducing a radio frequency magnetic field in said sector, said radio frequency magnetic field polarized substantially orthogonally to said static magnetic field, said static magnetic field and said radio frequency magnetic field particularly shaped to excite nuclei within said sector; anda receiver for detecting nuclear magnetic resonance signals from said sector.