Radioactivity of drill cutting samples collected from the oil industry area and assessment of their hazard

The drilling fluid is a complex colloidal mixture of water, bentonite clays, chemical additives and trace amounts of oil from the sludge of hydrocarbon bearing zones. Drilling fluids,including various mixtures, known as drill cuttings, perform an important role in drilling operations in the exploration and production of oil and gas. A relatively large amount of solid waste stream from drilling operations in the exploration and production of oil and gas is generated depending on the size of the well and the types of drilling mud used in the drilling process. The environmental impact of drilling waste can be devastating and dangerous to water and land receptors. All rocks have some radiation in them. Rocks in and around some oil and gas reservoirs may contain natural radioactivity. Drilling through these rocks or carrying them to the surface can lead to the formation of waste containing radioactivity. The ultimate sources of most of the radioactivity are from daughter products of uranium (²³⁸U, ²³⁵U) and thorium (²³²Th) that are naturally present in subsurface formations from which oil and gas are produced. Therefore, the providing of radio ecological monitoring for estimation of radioactivity and radiation risks has a scientific and practical importance.