Development of a novel relationship between salt content and radium concentration in crude oil

Radium is one of the most important natural radioactive sources associated with crude oil and its extraction processes. The importance of this radioactive element is highlighted by its ability to precipitate inside oil pipelines, forming what is known as scales. Depending on its concentrations in the extracted oils, its concentrations vary according to the type of oil reservoir and its geological formations. The aim of the current study is to find a mathematical relationship linking the salt content of crude oil with the concentration of radium. Thirty samples of crude oil were taken from the fields in Thi Qar province, Iraq, and tested to determine the concentrations of radium resulting from the 238U and 232Th series using gamma ray spectroscopy based on a sodium iodide scintillation detector with dimensions of 3 × 3 inch. At the same time, the salt content was also determined in each of the studied samples. The obtained results were used to create a mathematical relationship linking the radioactive concentration of radium isotopes to the salt content in crude oil. The relationship showed an accuracy of nearly 90% and demonstrated a direct relationship between the salt content and the concentrations of radium isotopes.