Abstract: The logging experiments and the analytical methods with neutron-Gamma-ray
spectra from simulative formation elements are studied in the model boreholes. Namely, the analytical methods are studied for inelastic & capturing Gamma-ray spectra, respectively. The formulae of the quality fractions of the formation elements are derived theoretically by means of the inelastic & capturing Gamma-ray spectra, respectively. Two spectra union analytical and normalizing methods are used. The quality fractions of all formation elements in rock matrixes and porous fluid are found out. The practical applications are performed in oil field. The results show that the method is successful.