Saying icy water and thicker crude in the Passage would cause oil to sink
rather than coat the shore is, quite literally, cold comfort.
L.D. Cross (author, The Quest for the Northwest Passage:
Exploring the elusive route through Canada’s Arctic waters.
Beaufort Sea Project Reprints - Oil Spill Countermeasures
The first part of this book describes the rudiments of an undersea well, the precautions
that are taken to resist the forces that cause a blowout, and the nature of ice into which
oil could leak.
The latter part addresses questions and challenges that would arise in the event of an
uncontrolled blowout: determining how oil and gas interact with ice, tracking the oil and
cleaning it up ? both on the water and on shorelines, and disposing of the collected oil and
associated contaminated materials.
The premise is that blowouts do happen, principally because of human error,
notwithstanding extensive precautionary practices. In 1974 an experiment was conducted in
Saanich Bay, British Columbia, involving the release of large volumes of compressed air at
sea-floor level to simulate an uncontrolled release of gas from a well. This led to a new
understanding of horizontal and vertical water flows surrounding the vertical plume of air.
It indicated that a certain degree of natural confinement of oil released simultaneously with
the gas would occur initially; over time, however, the combined behaviour of the gas and oil
in icy conditions would increase the rate of oil spread.
When associated with ice, oil takes several distinctly different forms, and therefore
many different techniques are needed to recover it. A worst condition prevails when oil is
entrapped in moving polar pack ice. It could take years for such oil to be released. Based
on the assumptions made in this study, a swath of contaminated ice 1 km wide by 600 km long
could form during a single winter. The frozen seas result in completely different and quite
dynamic working environments - 11 weeks of darkness - severe storms – only 15 to 30 calendar
days available to get the job done. Ice conditions would not permit the use of heavy machinery.
Tracking of contaminated ice is crucial. The assumption is made that a likely time for a
blowout would be the end of a drilling season. Descriptions are given of multiple techniques
to track movement during the winter months, when capping of a blowout and recovery of the oil
are deemed to be virtually impossible. The scenario is given of the release of 67,000 tonnes of oil.
During experiments conducted in Balaena Bay on the Beafort Sea coast confined quantities
of oil were released under ice, and this led to an understanding of the mechanism by which
oil seeps through ? or is entrapped beneath ? ice. Trial burns of oil generated voluminous
quantities of sooty black smoke and tarry residue of from 10-60 per cent of the volume of
oil available for burning. Ignition of the oil required priming with gasoline, and as many
as 6 burns were needed over 20 days to effect reasonably complete disposal of the oil.
What can be done with oil that is recovered, be it from ice, sea surface, or the
different types of shoreline? In the Beaufort Sea area at least, there is no land on which
the oily materials can be dumped without very extensive civil-engineering work, and ongoing
care would be required.
The book’s epilogue repeats 11 conclusions published in early 1978 by the Environmental
Protection Services’ Draft Review of Potential Beaufort Sea Oil Spill Countermeasures.
They encapsulate the vigilance that will be required, and questions that need addressing,
before undertaking drilling that involves a risk of under-ice release of oil and gas. It
would appear that the only way to avoid extensive contamination of Beaufort Sea beaches,
and consequent damage to wildlife, is to guarantee that if a blowout should occur at an
offshore drilling site, it will be brought under control rapidly.
Oil Spill Countermeasures - The Beaufort Sea and the Search for Oil (reprint)
by S.L. Ross; W.J. Logan; Wade Rowland
Edited by A.R. Milne
Reproduced with the permission of Her Majesty the Queen in Right of Canada, 2010.
67 pages (PDF format - 82 MB)
|