Characterization of Naturally Occurring Radioactive Material (NORM) Generated from the Lower Cretaceous Carbonate Formations in the Arabian Peninsula and Gulf

For most of the petroleum reservoirs in the world, the impact of the mother nuclides such as uranium-238 on the deposition of radioactive materials a.k.a. NORM from the formation and particularly as mineral scales adherent to tubulars and other equipment is considered insignificant. Uranium is regarded as insoluble in the reservoir formation and the prevailing understanding is that dissolved radium is not generated necessarily by U and Th in solution. Consequently, “uranium scale”, as a technical term, seems to be non-existent in the oil and gas industry. However, gamma spectroscopy and chemical analysis of NORM scale samples of carbonate origin, performed in the course of this research, has proven that they actually can contain uranium. A fundamental relationship between uranium and vanadium in scales is presumed. The highest specific activity of 238 U in scale analyzed with gamma spectroscopy was at 11.4 [Bq/g] and supplementary chemical analysis has shown concentrations of up to 740 ppm total uranium and up to 260 ppm vanadium.