Washington : BP said it has reinstalled a device on its Gulf of Mexico well to capture leaking oil, as an intercept well intended to plug the gusher began homing in on its target.
BP said in a statement it had "successfully reinstalled" the cap containment device on the well and resumed funnelling oil and gas to the drillship Discoverer Enterprise on the surface.
The cap was yanked from the seabed well after it was rammed by a remotely operated vehicle, US Coast Guard Admiral Thad Allen, said at a press conference in Washington. BP said it suspected no damage.
BP said drilling to intercept the leaking well and seal it permanently with mud and cement advanced Wednesday, as engineers began a series of ‘ranging' tests to guide the drill to its target. The so-called relief well has reached 16,000 feet below the ocean surface and BP expects to plug the damaged well at 18,000 feet.
"The relief wells are on course," Mark Salt, a BP spokesman, said in a tele-phone interview yesterday. A rig drilling a second relief well has paused for tests, Salt said.
Ranging tests determine a bearing and distance to the target well, with each test taking three to five days, or more, said Tad Patzek, chair of petroleum and geosystems engineering at the University of Texas at Austin.
The range tests require drilling for several hundred feet, withdrawing the drill, lowering instruments down the hole to locate the leaking well, removing the instruments and drilling a few hundred feet more, he said in an interview on Tuesday. "You want to go gently," Patzek said. "Any abrupt change in trajectory is a potential for another delay, an opportunity to begin fishing for something that's stuck."
Previous experience
Using similar ranging equipment, PTT Exploration & Production needed a month to kill its Montara leaking well in the Timor Sea off Australia last year, according to a report filed with national regulators.
After missing on the first three attempts over 11 days, the drilling team determined they were less than a half metre from their target when a ‘whipstock', a wedge intended to divert the drill at a sharp angle, became stuck, forcing them to back up 100 metres to try again, before hitting the well.
Once the relief well is at depth, it might take weeks to seal, Patzek said. "They may have to, essentially, kill the reservoir around the wellbore. That means, if nothing else, much larger volumes of mud." The Discoverer Enterprise drillship accounted for 62 per cent of 27,090 barrels of oil BP collected from the well June 22, BP said in a statement on its website. The rest was burned aboard a rig, the Q4000.
The vessel may need to begin preparing to evacuate should a hurricane approach the Gulf, the coast guard's Allen said. The rig and a planned third vessel could stay in place longer, he said.
Government forecasters say the hurricane season that started on June 1 may be the worst since 2005, when storms including Katrina devastated New Orleans and damaged platforms and pipelines in the Gulf of Mexico. Weather forecasters said a tropical storm or even a hurricane may develop in the Gulf of Mexico this weekend.
A collection of thunderstorms known as a tropical wave has dropped rain on Cuba, Jamaica and Hispaniola and is expected to organise into at least a tropical storm by Sunday, said Jim Rouiller, a meteorologist at Planalytics in Berwyn, Pennsylvania.
