Abstract: The present disclosure relates to borehole logging methods and apparatuses for estimating at least one parameter of interest of a volume of interest of an earth formation using nuclear radiation. The method may include obtaining an energy spectrum; using at least one processor to remove at least one energy spectrum component using a method selected from a spectral decomposition and spectral windows method; and estimating the concentration of at least one radionuclide using the energy spectrum after the removal. The estimation of the at least one radionuclide concentration may include using the other of the method selected form the removal. The apparatus may include at least one processor configured to perform the method.

Abstract: The present disclosure relates to borehole logging methods and apparatuses for estimating at least one parameter of interest of a volume of interest of an earth formation using nuclear radiation. The method may include obtaining an energy spectrum; using at least one processor to remove at least one energy spectrum component using a method selected from a spectral decomposition and spectral windows method; and estimating the concentration of at least one radionuclide using the energy spectrum after the removal. The estimation of the at least one radionuclide concentration may include using the other of the method selected form the removal. The apparatus may include at least one processor configured to perform the method.

Abstract: The present disclosure relates to borehole logging methods and apparatuses for estimating a density of an earth formation using nuclear radiation, particularly by detecting naturally emitted gamma ray spectra. The method may include estimating a naturally emitted total gamma ray spectra; generating one or more simulated naturally emitted gamma ray spectra; and estimating the density of the earth formation using a comparison between the naturally emitted gamma ray spectra and at least one of the simulated naturally emitted gamma ray spectra. The apparatus may include at least one radiation detector configured to generate gamma information about an earth formation; and at least one processor configured to generate at least one simulated naturally emitted gamma ray spectra and to estimate the density of the earth formation using a comparison of the at least one naturally emitted gamma ray spectra with the at least one simulated naturally emitted gamma ray spectra.