The study highlights the evaluation of radioactive materials within the clay and shale units of the Tanazeft Formation in well X1, located in the El-Feel Field, using Natural Gamma Ray (NGR) spectrometry to determine the concentrations of the radioactive elements K, U, and Th. Gamma-ray logs recorded values ranging from 116 to 200 API, with a notable increase in the lower section of the well, indicating higher abundances of clay minerals enriched in radioactive elements. The uranium curves and the Th/U ratio show a strong correlation with depositional conditions and organic carbon content, making them effective indicators of radioactive activity within the formation. The study also indicates that produced water associated with oil extraction contributes to transporting radioactive isotopes to the surface or depositing them on drilling equipment, thereby increasing the likelihood of naturally occurring radioactive material (NORM) contamination at production sites. Based on geological comparison with similar, well-documented regions, the findings reveal a potential radiological risk that necessitates a strict regulatory framework and specialized field safety programs to protect workers and the environment.............. Keywords:............ clay minerals, gamma ray, NGR, Murzuq Basin, oil radioactive contamination.