Naturally occurring radioactive materials

Naturally Occurring Radioactive Materials (NORM) include a wide range of radioactive isotopes that include elements such as carbon 14 and potassium 40, both of which are present in the human body. But the main radioactive elements involved in oil and gas production are those found throughout earth's crust, specifically those present in the formations from which oil and gas are produced. These elements include Uranium and Thorium and their respective daughter products, including Radon gas.

Testing for NORM

Scaling in downhole and surface production equipment is well known where water-drive reservoirs are in production. Sulfate scales, mainly consisting of barium, strontium, and calcium, occur on surface and downhole equipment. Radium traces could be present in such scales. causing radioactivity. Cleaning such scaled equipment for future use can present a potential health hazard. Alternately, the equipment may have to be removed, stored, and disposed of according to established procedures for low-level radioactive waste.

Measuring radiation levels at the wellsite requires the use of rugged gamma ray survey meters by specially trained personnel. The measurement of low levels of radiation on individual tubing sections can be difficult in the presence of natural background radiation. Fortunately, gamma ray well logging tools are highly sensitive instruments that can measure radiation inside scaled tubing in wells with less sensitivity to background signal. Evaluation of scale radioactivity before removal of tubing from the well benefits from a a reconnaissance logging technique that uses a gamma ray logging tool calibrated specifically for radium.