BP Plc reinstalled a device on its Gulf of Mexico well to capture leaking oil after an underwater accident yesterday, as an intercept well intended to plug the gusher began homing in on its target.
BP said in a statement last night it had “successfully reinstalled” the cap containment device on the well and resumed funneling oil and gas to the drillship Discoverer Enterprise on the surface. Oil diverted to vessels on the surface declined yesterday by 10,260 barrels, or 38 percent, London-based BP reported on its website this morning.
The company yanked the cap from the seabed well after it was rammed by a remotely operated vehicle, U.S. Coast Guard Admiral Thad Allen, said at a press conference yesterday in Washington. BP said it found no damage.
Drilling to intercept the leaking well and seal it permanently with mud and cement advanced yesterday, as engineers began a series of “ranging” tests to guide the drill to its target, the company said. The so-called relief well has reached 16,000 feet (4,876 meters) 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 telephone interview yesterday. A rig drilling a second relief well has paused for tests, Salt said.
BP fell 8.25 pence, or 2.5 percent, to 325.25 pence at 4:35 p.m. in London trading, the lowest closing price since November 1996. It has lost half its value since the April 20 blowout of the well that destroyed the Deepwater Horizon drilling rig, killed 11 crew members and triggered the biggest oil spill in U.S. history.
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 a June 22 interview.
“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.”
Using similar ranging equipment, PTT Exploration & Production Pcl 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 PTT drillers determined they were less than a half meter 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 meters 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 interruption yesterday was the third time BP has had to halt oil capture to the Discoverer Enterprise drillship. The two prior occasions involved fire and equipment problems.
The drillship accounted for 62 percent of the 27,090 barrels of oil the company collected from the well on June 22, BP said in a statement on its website. The rest was burned aboard another rig, the Q4000.
The drillship may need to begin preparing to evacuate should a hurricane approach the Gulf, the Coast Guard’s Allen said. The Q4000 and a planned third vessel could stay in place longer, he said.
Government forecasters say the hurricane season that began June 1 may be the worst since 2005, when storms including Katrina devastated New Orleans and damaged platforms and pipelines in the Gulf.
Weather forecasters said a tropical storm or even a hurricane may develop in the Gulf this weekend.
A collection of thunderstorms known as a tropical wave has dropped rain on Cuba, Jamaica and Hispaniola and is expected to organize into at least a tropical storm by June 27, said Jim Rouiller, a senior energy meteorologist at Planalytics Inc. in Berwyn, Pennsylvania. If the storm forms, it will be named Alex.