Abstract: Nuclear magnetic resonance well logging apparatus and a method of use for geophysical examination of a bore hole as the bore hole is drilled. The apparatus is connected to the drill bit to follow it through the bore hole as the bore hole is formed. The apparatus comprises a resilient, tubular, permanent magnet for generating a static magnetic field in the region of a portion of the bore hole adjacent the apparatus, which region includes materials sought to be analyzed, an antenna mounted on the magnet and connected to associated circuitry for exciting nuclei of the materials sought to be analyzed in the region, and a receiver connected to the antenna for receiving nuclear magnetic resonance signals from the excited nuclei and for providing an output signal indicative of properties of the materials sought to be analyzed.

Abstract: A method for conducting borehole NMR measurements comprising the steps of:providing a magnetic field and a magnetic field gradient at a desired location along a borehole;carrying out at least one NMR experiment in the presence of the magnetic field gradient;sensing the diffusion effect on the decay of at least the first echo; anddetermining therefrom the diffusion coefficient.Apparatus for carrying out the method is also described.

Abstract: Nuclear magnetic resonance sensing apparatus including at least three magnets operative to generate a static magnetic field in a region remote therefrom containing materials sought to be analyzed, the at least three non-conductive permanent magnets being arranged along a longitudinal axis in side to side arrangement and having generally uniform cross sections, which, when joined, together define a circular cross section, the overall length of said at least three magnets along said longitudinal axis being greater than their dimensions perpendicular to said longitudinal axis and greater than twice the radial separation of said remote region and said longitudinal axis, the at least three magnets being magnetized in magnetization directions extending generally perpendicular to the longitudinal axis, at least one of the at least three magnets having a magnetization direction opposite to the magnetization direction of at least another one of the at least three magnets, the static magnetic field having a static fiel

Abstract: Nuclear magnetic resonance sensing apparatus includingone or more magnets operative to generate a static magnetic field in a region remote therefrom containing materials sought to be analyzed, the one or more magnets defining a longitudinal axis, the static magnetic field having a static field direction substantially perpendicular to the longitudinal axis and having generally uniform amplitude along the azimuth with respect to the longitudinal axis in the remote region;apparatus for generating a variable magnetic field in said remote region in a direction substantially parallel to the static magnetic field;apparatus for generating a radio frequency magnetic field in the remote region for exciting nuclei of the materials sought to e analyzed and having a radio frequency magnetic field direction substantially perpendicular to both the longitudinal axis and to the static field direction; andapparatus for receiving nuclear magnetic resonance signals from the excited nuclei and for providing an output indication o

Abstract: Nuclear magnetic resonance sensing apparatus including one or more magnets operative to generate a static magnetic field in a region remote therefrom containing materials sought to be analyzed, the one or more magnets defining a longitudinal axis, the static magnetic field having a static field direction substantially perpendicular to the longitudinal axis and having generally uniform amplitude along the azimuth with respect to the longitudinal axis in the remote region;apparatus for generating a radio frequency magnetic field in the remote region for exciting nuclei of the material sought to be analyzed and having a radio frequency magnetic field direction substantially perpendicular to both the longitudinal axis and to the static field direction; andapparatus for receiving nuclear magnetic resonance signals from the excited nuclei and for providing an output indication of the properties of the material sought to be analyzed.Methods for nuclear magnetic resonance sensing are also described and claimed.