BP’s containment problem is unprecedented
The oil spill in the Gulf of Mexico presents BP Exploration and Production with a problem of unprecedented severity — a limitless gush in very deep waters — forcing the London-based company to grasp for fixes that have never been tried before.
The problem with the April 20 spill is that it isn’t really a spill: It‘s a gush, like an underwater oil volcano. A hot column of oil and gas is spurting into freezing, black waters nearly a mile down, where the pressure nears a ton per inch, impossible for divers to endure. Experts call it a continuous, round-the-clock calamity, unlike a leaking tanker, which might empty in hours or days.
“Everything about it is unprecedented,” said geochemist Christopher Reddy, an oil-spill expert and head of the Coastal Ocean Institute at the Woods Hole Oceanographic Institution in Massachusetts. “All our knowledge is based on a one-shot event…. With this, we don’t know when it’s going to stop.”
Accidents have occurred before in which oil has gushed from damaged wells, he said. But he knew of none in water so deep.
And “everything is bigger and more difficult the deeper you go,” said Andy Bowen, a research specialist who works with undersea robotics at the Woods Hole center. “Fighting gravity is tough. It increases loads. You need bigger winches, bigger cables, bigger ships.”
An analogy, he said, is the difference between construction work on the ground versus at the top of a mile-high skyscraper.
To BP falls the daunting task of trying to stop the gush before it becomes the most damaging spill in American history. If the flow is not stopped, it will exhaust the natural reservoir of oil beneath the sea floor, experts say. Many months, at least, could pass.
The company is working on three fronts at once.
Two options for blocking the flow are difficult, but at least rely on conventional technology. A third option — corralling the plume of oil and diverting it into a processing ship’s hold — “has never been done in that depth and is stretching the boundaries,” said BP spokesman Daren Beaudo.
But BP has no choice. Failure to stop the flow of oil from the sea bottom could undercut all other efforts underway to combat the spill, said Reddy.
Planning, training and experience with other oil spills has produced a “crack team” of spill fighters working with boats and booms combating the slick on the surface, Reddy said. But unless the well underwater stops belching oil, all that expertise will be overwhelmed by a growing toxic mat spreading across the gulf. “The responders can only do so much,” he said.
The April 20 accident 50 miles off the Louisiana coast is presumed to have killed 11 people. It occurred 5,000 feet under the sea — many times deeper, for example, than any platform now drilling off the California coast.
A Transocean oil rig hired by BP had just explored a new oil deposit and was preparing to cement shut the well it had bored so that it could later be opened for production.
It’s not clear how the explosion happened. But industry experts say natural gas mixed with oil may have leaked up the long “riser,” or pipe, used to encase the drill and extract mud from the well. Natural gas expands as it is released from the seafloor and flows up. It can easily spark and explode.
In the disaster that followed, the rig sank, and the riser bent and broke in at least two places. Key to the catastrophe was the failure of a “blowout preventer” sitting on the seafloor on top of the well. This heavy contraption of valves and hydraulics failed to perform its most important function: shutting a valve to prevent oil from escaping. BP officials say they believe there was an attempt to activate emergency systems, but the systems didn’t work.
The result is what Reddy called “an upside-down faucet, just open and running out.”
BP’s first deployed robotic submarines to shut the valve. This the quickest fix. If the people operating the robots could shut the blowout preventer, it would block the top of the well.
The submarines use technology similar to NASA rovers on Mars. A tether connects them to a nearby ship where operators steer them from a control room. The operators are highly skilled, and the subs have robotic arms, so agile and delicate “they could give you three stitches on your forehead,” Reddy said.
But experts say conditions for this work are profoundly difficult. The robots are charged with complex, unplanned mechanical work in deep seas next to a whirl of rising oil. Even if their lights can illuminate more than a couple dozen feet, the subs may be knocked around, and must dodge broken wreckage at the same time.
“The biggest hazard is having a robot become entangled in debris, pipes and cable,” said Bowen. “This is a huge industrial accident, and that makes it very difficult for them to operate from above.”
In any case, days have passed, and hope is waning that the robot mechanics will succeed.
So BP is working on two other plans, one relying on conventional technology. Another hole would be drilled into the seafloor near the accident site. Heavy material and cement would then be squirted into the new hole in an attempt to plug up the reservoir. But this process could drag on for 90 days, BP officials say.
So workers in Port Fourchon, La., are working on an unproven concept: They are constructing three large “subsea oil collection” systems. These are essentially 40-foot-tall steel boxes that BP plans to lower over the gushing sources in order to contain the oil and channel it up through pipes to a waiting processing ship.
The ship, called the Enterprise, is already being prepared in the gulf, and one of the three chambers has already been completed by Wild Well Control, an oil-disaster response company.
But considerable technical difficulties lie ahead. The huge chambers must be lowered in place and the pipes suspended and properly positioned. BP has successfully used this strategy against shallow water leaks after hurricanes Katrina and Rita, officials said. But in deep water, “it has never been done,” Beaudo said.
The engineers are designing the new system without exact knowledge of the flow and force of the oil. Buoyancy and heat will force the oil upward, said David Valentine, a geochemist at UC Santa Barbara. But there is danger of pressure building in the chamber as the oil gushes in. Or oil that is mixed with gas might cool too quickly as it rises, stiffen, and clog the pipes, Valentine said.
BP said it will take two to four more weeks to build and install the collection systems. Until it stops the gush, the company’s liability “is essentially unlimited,” Bowen said.
And once the emergency abates, BP faces tough questions. Oil industry experts this week compared the accident to a plane crash or space shuttle disaster that may have been the result of a cascading chain of mishaps. There are supposed to be safeguards: sensors that detect changes in pressure, cross-checking protocols, emergency response systems, and people monitoring everything 24 hours a day aboard the rig and by satellite.
“We are all very curious,” said an industry source who asked not to be identified because he worked for a rival oil company. “What happened that all that equipment, all the computer power, all the automated systems and manpower in place, could not be invoked to stop this?”
The assumption is that an oil-rig perfect storm occurred, very quickly. “There would have been a dozen barriers that had to fail in order for this accident to happen,” said Tim Robertson, an oil-spill consultant with Nuka Research and Planning Group in Alaska.
Perhaps the biggest question, to experts, is why the blowout preventer valves didn’t shut. The huge device, which caps the well, is equipped with emergency systems, including a “dead man’s switch,” a device of last resort that is supposed to be fail-safe.
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