Installation of new cap on Gulf of Mexico well begins Saturday
The new cap has three parts, including a small blowout preventer that would be used to "shut in," or contain, the oil within the well, Allen said.
The new cap's success in shutting in the well will depend largely on the pressure inside the well, Allen said. Now at 12,000 pounds per square inch, the hope is that pressure would equalize inside the well and fall to 9,000 pounds per square inch when the new cap is in place, Allen said. If that happens the well would be left alone until a relief well permanently seals it in mid-August, meaning no vessels would be needed to pump oil from the well,
But if pressure falls below 9,000 pounds per square inch after the new cap is put in place it will be a sign that there is damage to the well and that oil is perhaps escaping from places beneath the surface, Allen said. In that case, engineers would continue producing from the well, by collecting oil through a four-device containment system that would include the ships Discoverer Enterprise, Helix Producer and Clear Leader and the floating platform, Toisa Pisces. All together those vessels would have the capacity to collect 60,000 to 80,000 barrels of oil per day.
The condition of the well, as determined by the shut-in attempt, will also give engineers important clues about how to proceed with intercepting the damaged well with the relief well, Allen said.
"That all is going to be important information for how we are going to attempt to kill the well from the bottom," Allen said. "As far as injecting mud, how much mud will need to be injected to fill that column? Will some of it maybe go out into the formation if there's a problem with the well bore and the casings? So we actually improve our chances of the bottom kill by being able to put that cap on and get a pressure reading at the top."