Chemical and hydrodynamic processes leading to accumulation of radioactive scales on technological equipment as well as their chemical, radiochemical and isotope composition are considered. Radioactive wastes that accumulate in a considerable volumes in the oil-field objects such as gathering and sedimentation tanks as well as sand collectors are also investigated. Principal ways of radioactive contaminated materials treatment are offered.
Radio-active scales on technological oil producing and desalting - dewatering equipment and radioactive wastes are represented with insoluble sulfates of Ra226, Ra228 isotopes and products of their decay. As the larger radioactive contaminated wastes volumes, the higher their disposal costs the technologies goal is to minimize waste volume. The technological processes includes two stages:
separation of hydrocarbons and water for further use, from the mineral part,
extraction of radioactive elements compounds from the mineral part.
This part of radioactive wastes should be disposed and its volume is not higher than 1.0 - 1.5 % of the initial waste volume. Specific activity of recovered hydrocarbons, water and remaining mineral part does not exceed safe level.
Radioactive scales were discovered on technological equipment connected with production, transport and treatment of oil and gas in many oil-producing regions of the world.
In the former Soviet Union radioactive scales contaminations were found in oil fields of the Western Siberia, the Northern Caucasus, Apsheron and some other regions.
Radioactive scales were found on the well equipment (tubing, electric centrifugal submersible pump - ECSP) in the Tatarstan oil fields for the first time in the middle of 1960-s. 22% of tested wells have been contaminated with radioactive scales in the early 1970-s. The number of cases of radioactive Contamination of tubing and pumping equipment decreased sharply in 1970 – 1975. Only single cases of radioactive scales occur on this equipment nowadays.
Repeated cases of radioactive scales were detected on the technological equipment of gathering, transport and oil treatment systems in 1990 - 1991.