No immediate end to ‘worst environmental disaster’

Author : Paul Gay

01 June 2010

As the Mexican Gulf oil spill disaster enters its sixth week, it is feared by BP that the leak from Well MC252 could pollute the seas until August, when two relief wells currently being drilled stem the flow of oil. In the meantime millions of barrels of oil spew into the Gulf, creating what President Obama terms the worst environmental disaster in US history. And the latest attempt to stop the flow oil has failed.

Oil is now affecting an area the size of Luxembourg

The plan to kill the well by injecting heavy drilling fluids through the blowout preventer (BOP) on the seabed has failed to stem the flow of oil and gas and despite successfully pumping a total of over 30,000 barrels of heavy mud in three attempts at rates of up to 80 barrels a minute. BP's so called 'top kill' operation, which also fired materials such as golf balls and shredded tyres into the BOP to clog it, will now be followed with the use of a containment device known as a lower-marine riser package cap, a piece of equipment that sits on top of the failed blowout preventer at the seabed, 5000 ft below the surface of the sea, where only robots can operate.
Other attempts to stop the crude include using remotely operated submarines to trigger the switches to close the blowout preventer valves and placing the Top Hat, a steel and concrete container, over the broken pipe to collect the oil.

Proposals that have not yet been tried include a smaller top hat containment dome to collect the escaping oil, in the hope that it would be less vulnerable to the ice crystals that stopped the larger container from working; attaching a new BOP to the top of the failed valve and inserting additional pipes to draw off more of the oil to be collected by ships. This technique has already been attempted with partial success.

The leak followed the explosion and sinking of the Deepwater Horizon rig on 22 April with the loss of 11 workers. The spill is now thought to have cost BP about $940m and this figure could well treble by the time the leak has been stemmed and the contaminated area, which is now about the size of Luxembourg, has been cleaned up.

US government advisers have estimated that the volume of oil released so far is at least 450,000 barrels, which is already greater than the 260,000 barrels in the 1989 Exxon Valdez spill, hitherto the worst disaster of its kind in the US. A further 12,000-19,000 barrels were estimated to be escaping daily.

Shares in BP fell on the London Stock Exchange when markets reopened on Tuesday after the Bank Holiday. Traders reacted to the news that its latest attempt to cut the rate of oil leaking from its well in the Gulf of Mexico had failed. BP shares, which have already lost about a quarter of their value since the leak began in April, fell to their worst level since March 2009.