Natural gamma-ray (GR) well-logging technique is used to estimate the radioactive heat production (HP) parameter as a function of depth, in the phosphatic Khneifis deposit in Palmyrides region in Syria. Seven available drilled wells with their natural GR records are used to characterize and estimate the HP magnitude in the study region. The analysis of 2660 measured points in those wells shows that HP varies between a minimum of 0 and a maximum of 7.97 μw/m3, with an average of 1.33 μw/m3 and a standard deviation of 1.68 μw/m3.Multi-fractal approach with the use of concentration-number (C-N) model and log–log plots is originally proposed and used as a new approach for characterizing the HP variations and isolating different HP populations in the study region. The high HP ranges are mainly related to the phosphatic layers, relatively enriched by uranium concentrations, comparing with their surroundings.