MANAGEMENT OF NORM IN THE PETROLEUM INDUSTRY Akpojevwa Tega Naomi, october 2016 | Page 31

geological formation), sulphate-reducing bacteria have been shown to enhance
the uptake of uranium which is deposited in bio-fouling deposits4, 5. In many
seawater injection systems this may not pose a significant hazard, however,
systems which utilise large quantities of seawater may encounter levels of
uranium in bio-fouling which present a risk to workers and a problem for waste
disposal. Concentrations of uranium up to ~2% by weight have been identified
in seawater injection systems.
2.1.5 Produced Water
In the petroleum reservoirs, crude oil co-exists with underground water, usually
called ‘formation water’ or ‘formation brine’. While the initial oil production
process is usually dry (Smith, 1992), as the reservoirs pressure falls over time,
water can be also co-produced with the crude oil, and this water is given the
name ‘produced water’.
The major radionuclide found in the produced water includes Radium-226,
Radium-228, Radium-224 and Lead-210, in concentration of up to few hundred
Becquerel’s per litre (IAEA, 2003).
The largest amount of waste produced by the oil and gas industry is produced
water. The ratio between oil produced and produced water is about 1 x 10 -1 or
0,33 meaning that for each one cubic meter oil extracted, three cubic meters of
produced water is co-produced. The ratio in the gas production is significantly
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