BP, Obama administration must decide soon whether to switch oil containment caps

BP, the government and an army of volunteers are fighting to contain and clean the millions of gallons of oil spewing from the site of the Deepwater Horizon explosion in the Gulf of Mexico.
By Steven Mufson and Joel Achenbach
Washington Post Staff Writers
Friday, July 2, 2010; 7:24 PM

BP and Obama administration officials are nearing a major decision as they head toward what they hope will be the oil spill endgame: whether to change the cap that is capturing a significant amount of the oil leaking from the damaged Gulf of Mexico well.

There are two main arguments for the switch. First, a new cap -- with a stronger fit near the sea floor and more flexible pipes to the surface -- would make it easier for ships to disconnect and reconnect quickly if a storm blows in. Second, it could boost the chances of successfully setting a concrete plug when the relief well cuts into the damaged hole.

But changing the containment cap would also create some white-knuckle deep-sea engineering moments and, for a week to 10 days, could let some of the oil flow freely again into the gulf. The Discoverer Enterprise, one of the ships now collecting oil, would be disconnected during that time.

BP briefed Obama administration officials and formally proposed installing the new containment cap on top of its damaged Gulf of Mexico well on Wednesday. Administration officials indicated Friday that they were leaning toward approving the plan.

But the officials said they first want to wait for a new ship, the Helix Producer, to be connected to the well through the "kill line," one of the hoses leading from the damaged blowout preventer that sits on the sea floor. The Helix Producer will be able to capture up to 25,000 barrels a day and offload the oil to a tanker. The new ship can be connected once the sea waters, roiled by Hurricane Alex, calm down. National incident commander and retired Coast Guard Adm. Thad W. Allen said that the Helix should be working by next Wednesday.

The Helix Producer's capturing capacity will be added to the 10,000 barrels a day going through other "choke" lines to another ship, called the Q4000. Together the two vessels could capture as much as 35,000 barrels a day of oil while the existing containment cap is replaced. That would be slightly more than the amount being captured now.

But while the cap is installed, the "top hat" that is now collecting oil from the well would be removed and additional oil would gush from above the blowout preventer, a point familiar to millions of viewers who have been watching live sub-sea video provided by BP. How serious that would be depends on how much oil is flowing from the well. At the low end of government estimates, the addition of the Helix Producer would mean that hardly anything would leak out during the switch in the containment cap; at the high end of the estimates, as much as 25,000 barrels a day or more could still pour forth.

Another key, but unknown, factor in the calculations is the weather. Forecasters say this will be an intense hurricane season and Hurricane Alex, which just passed west of the damaged BP well, is the first June hurricane to hit the gulf since 1995, administration officials said.

The existing containment cap isn't very robust during hurricane season. It would take up to 120 hours for the Discoverer Enterprise ship to disconnect from the well, pull up the mile-long riser pipe and sail to calmer waters, Allen said Friday.

A more flexible system is being constructed beneath the sea. Two floating riser pipes are coming up from the sea floor. They can be attached to surface ships with flexible hoses. To put that system in place, BP engineers would remove the loose-fitting cap on the well, remove a damaged section of pipe, and install the new, tight-fitting cap.

That could also make it possible to essentially shut-in the well entirely. Unlike the existing containment cap that sits uneasily on the pipe sticking up from the top of the blowout preventer, the new cap would be able to withstand up to 9,000 pounds per square inch of pressure. As a result, the new cap could create back-pressure that would be helpful in the all-important bottom-kill effort that will take place when the first relief well finally reaches the base of the blown-out well, which BP named Macondo.

On Tuesday, officials from BP, the Energy Department and other companies and agencies had a seven-hour meeting about the relief well and how to create optimum conditions for setting the concrete plug. One potential problem could arise if fluids are leaking out the sides of the well through damaged pipe and discs. That would undermine the effectiveness of the new cap in aiding with setting the cement plug.

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