A relief well being drilled deep into the sea floor of the Gulf of Mexico to shut down the gushing oil well could be completed ahead of a long-set deadline of mid-August only if conditions are ideal, government and BP officials said yesterday.
The relief well is currently the best hope for stanching the oil leak set off by the 20 April explosion aboard the BP-operated Deepwater Horizon drilling rig, which killed 11 workers and began an environmental catastrophe for the region.
National Incident Commander and retired Coast Guard Admiral, Thad Allen, said that the relief well is expected to intercept and penetrate the Deepwater Horizon well pipe about 5,500 metres below sea level within seven to 10 days.
But they won't know how long it will take to stop the oil until they get there. The well has several concentric rings, and oil could be coming up through multiple rings, Admiral Allen said. The plan is to pump heavy mud and then cement into the well to overcome the upward pressure of the huge oil reservoir below.
If the oil is coming through the outer ring of the well, then they will have to pump in mud and cement to stop that layer first. Then they would have to drill through the hardened cement and repeat the process in each ring until they reach the centre pipe and do it again.