Elevated concentrations of the radium isotopes Ra-224,Ra-226,Ra-228 exist in the scale and produced water in oil exploration. The activity concentration of Ra-226 was calculated from 186.2 keV peak with no usual spectral interference of 185.7 from U-235. The activity concentration of Ra-228 was calculated from its first daughter product Ac-228 using the 911.2 keV gamma rays since it is a pure beta emitter. The activity concentration of Ra-224 was calculated from Pb-212 using the 238.6 keV gamma-ray and the secular equilibrium equation with Ra-228. The IAEA 448 (oil contaminated field soil) reference material was used as a quality control for Ra-226,Ra-228 and but was unreliable for Ra-224 using Pb-212.