Seepage and gas bubbles detected around wellhead

The seepage feared to be linked to BP’s crucial well test in the Gulf of Mexico is three kilometres away from the actual wellhead, the White House said yesterday.

The US government earlier authorised BP to keep the busted well shut in for another 24 hours despite the mysterious seepage and other anomalies that could indicate the wellbore below the seabed is damaged and leaking.

White House spokesman Robert Gibbs did not elaborate on the “seepage”, but confirmed that gas bubbles had also been detected by underwater cameras around the actual wellhead.

A vessel belonging to the government’s National Oceanic and Atmospheric Administration (NOAA) had also discovered other “anomalies” that needed to be checked out, he added.

BP wants to keep the valves on its containment cap closed continuously until an operation to permanently seal the well can be performed in less than two weeks time, meaning no more toxic crude would stream into the Gulf.

But the government is granting extensions only in 24-hour increments and has ordered BP to be ready to remove the cap immediately if the seepage is confirmed to be methane.

Measuring devices on BP’s cap have given steadily increasing high-pressure readings since tests began last Thursday, indicating there are no major leaks in the wellbore.

Seismic and sonar surveys and video footage filmed by robotic submarines in the murky depths of the Gulf have also been monitoring whether any oil or gas was leaking through the rock formations on the sea floor.

The announcement last week that BP stopped the oil flow with a new cap, as it conducted key pressure tests on the well, had raised hopes of devastated coastal communities that their three-month nightmare may soon be over.

But fresh concerns were raised on Sunday after bubbles were detected at the site, even though BP said it did not believe they were caused by hydrocarbons – meaning the wellbore reaching deep to the oil reservoir below may be compromised and leaking oil, even as it is choked off at the wellhead.

BP has said the valves on the cap would remain shut as long as no leaks are discovered. The start of a two-week operation to plug the well permanently by pumping in heavy drilling fluids and then cement is now less than a fortnight away as engineers have only 30 metres left vertically to drill.

Gulf residents, who have seen the crude tarnish their shorelines and cripple the local economy since a rig leased by BP exploded and killed 11 workers in April, reacted cautiously to news that the cap was holding back oil.