Dan M. Arnold

A multi-function compensated spectral natural gamma ray logging system

A natural gamma ray spectroscopy logging system has been designed which incorporates active compensation for differences in borehole conditions into the least squares calculation of the K-U-Th elemental concentrations. A low atomic number toolcase allows gamma rays in the photoelectric energy region to be detected, while a coincidence gain stabilization technique distinguishes formation gammas from those originating in the stabilizer source. These features permit additional measurements of formation lithology in open holes and mean casing thickness in cased wells.