On Friday 28 February, four Weatherford drilling rig workers at a QGC coal seam gas (CSG) well site near Tara in Queensland were exposed to as yet undisclosed levels of radiation. They handled a radioactive equipment component left at the site by workers from another oil and gas services company, Schlumberger. The radiation source was not shielded and labeled as required by regulation.(1)
According to an anonymous source, radiation incident response personnel from the USA have been summoned to the Tara area to investigate and provide support. The health of the four workers is “under observation”.
Radioactive tracer material is used by drilling companies to measure the properties of rock and other materials where a well is being drilled to help determine the presence of water, gas or oil.
As a May 2002 press release from the US Nuclear Regulatory Commission (NRC) states, Schlumberger at that time temporarily lost control of a radioactive well logging source containing 1.2 curies of Cesium-137 at an oil rig site near Havre, Montana.(2)
In the 2002 incident, thirty-one oilfield workers were identified as being exposed to the source, including thirteen who received doses estimated to be in excess of NRC's 0.1 rem annual limit for individual members of the public.(3)
According to the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) document, the National Directory for Radiation Protection,(4) the requirements for bore hole logging or well logging include: the licence must require the licensee to comply with the ARPANSA/NOHSC Standard for limiting occupational exposure to ionizing radiation RPS1 (2002); the licence must require the licensee to comply with the Code of Practice for the Safe Use of Sealed Radioactive Sources in Borehole Logging (1989); and the licence must require the licensee to ensure the direct supervision of any field site while radioactive sources or radiation apparatus are in use, to ensure that unauthorised persons do not enter the site.(5)
1. http://www.arpansa.gov.au/pubs/rhs/rhs28.pdf www.arpansa.gov.au/pubs/rps/rps6.doc https://apps.legislation.qld.gov.au/Search/isysquery/e5a957ba-e7b9-4d03-...
4. National Directory for Radiation Protection, Radiation Protection Series Publication No. 6, www.arpansa.gov.au/pubs/rps/rps6.doc
5. The RHS 28 - Code of Practice for the Safe Use of Sealed Radioactive Sources in Borehole Logging has been adopted as requirements, licence or registration conditions in all states except South Australia. www.arpansa.gov.au/pubs/rps/rps6.doc