Assessment of naturally occurring radioactive material (NORM) in the oil drilling mud of Az Zubair oil field, Basra, Iraq

The concentration of naturally occurring radioactive material (NORM) in oil drilling mud samples collected from 14 geological formations begins with Dibdibba Formation depth (140–150 m) and ends with Ahmadi Formation depth (2764.5 m) of the oil well in Az Zubair oil field (ZB-296) in Basra governorate were determined using NaI gamma spectrometer. Gamma spectrometric analyses of natural radionuclides ²³⁸U, ²³²Th and ⁴⁰K have indicated average concentrations in Bq kg⁻¹ as 614.5, 233.0 and 6201.4 Bq m⁻³, respectively. Radon levels and radium contents for different formations were measured using solid state nuclear track detector CR-39. The obtained values of radon concentration were ranged from 209.3 to 1876.6 Bq m⁻³ and the values of radium content ranged from 0.76 to 6.79 Bq kg⁻¹ for Tayarat and Sa’adi formations, respectively.