Saturday, November 10, 2007
"Only a crude estimate can be made of the annual total 226Ra activity transferred from oil reservoirs to the surface. A United States Environmental Protection Agency (US EPA) study of 10 oil production wells analysed scale and sludge production rates. (11) The amount estimated was about 250m3 for a period of 20 years. The resulting amount of waste generated by one oil-producing well per year is about 2.25 tons, using a waste density of 1.8 tonnes.m-3. In order to derive an average 226Ra activity concentration, the same study used results of a large number of external gamma readings (6,274) taken in several oil production facilities and converted these to the activity concentration. There is a significant uncertainty attached to such a procedure because of the effects of equipment wall thickness, self-absorption of the radiation in the scale and thickness of the scale, and distribution of radium within the scale. The published average radium concentration was 4.6Bqg-1. Hence, the resulting estimate of total 226Ra activity brought to the surface is 918GBq per year. Similar studies are due to be undertaken in oil and gas-extracting facilities in other parts of the world, so an average 226Ra activity brought to the surface per year can be derived with any degree of certainty."
Posted by Elpaso at Saturday, November 10, 2007