Tighter cap fitted to gushing BP oil well

BP has successfully placed a tighter cap over the leaking oil well in the Gulf of Mexico, hoping it will stem the flow of toxic crude after 13 weeks. But the company warned the cap’s efficiency and ability to contain the oil and gas “cannot be assured".

Reuters

Robotic submarines relayed live pictures of the operation 1.6 kilometres below the surface.

The engineers will next aim to close valves on the 75-tonne system and start taking readings as its pressure sensors bear the brunt of the gusher.

The test, which will begin sometime on Tuesday, will last anywhere from six to 48 hours "or more depending on the measurements that are observed," said Admiral Thad Allen, the former Coast Guard chief who is leading the US government's response to the crisis.

If the pressure readings are high enough, BP officials have suggested the valves will be kept shut, effectively sealing the well.

But if they are too low that would indicate a leak somewhere in the casing of the well, which extends four kilometres below the sea floor.

"We need to make sure that the flow can't come around the well bore rather than through the well bore," explained BP's chief operating officer Doug Suttles.

An estimated 2.1 to 4.1 million barrels of oil has gushed into the sea since the BP-leased Deepwater Horizon sank on 22 April, two days after a deadly explosion.