Natural gas continues to leak off Texas coast
By DAVID BALLINGRUD
© St. Petersburg Times,
A stream of explosive natural gas is howling into the atmosphere over the Gulf of Mexico from a 20-inch well pipe sunk 7,667 feet into the sea floor.
The vast cloud is escaping with an ear-splitting shriek from the natural gas rig Marine 4, which blew out eight days ago, forcing the evacuation of 39 workers. One worker is missing.
"It sounds like a 747 taking off right next to your head," said Richard Hatteberg, a senior well control specialist who searched the rig for survivors less than an hour after the blowout.
Wary of causing a lethal conflagration, repair crews are seeking -- without success -- to cap or "kill" the well, which is 20 miles off the Texas coast.
Because the gas is dissipating in the atmosphere, environmental effects have been minimal, U.S. Coast Guard Petty Officer Tom Johnson said Friday.
"But it's still leaking gas, and there is potential for an accident," said Johnson, who is investigating the incident for the Coast Guard's Marine Safety Office in Galveston. "Vessels are being kept out of the area. Even a spark from a shoe buckle striking metal could set it off."
Marine 4 is one of almost 4,000 oil or gas drilling rigs in the Gulf of Mexico. Most are in the western gulf, out of sight and out of mind for most Floridians.
But that could change in coming years. The eastern gulf is rich in natural gas, and pressure for exploration and production is growing.
Just two days before the blowout, the U.S. Senate upheld the sale of oil and gas leases in Area 181 of the eastern gulf. About 1.5-million acres, some 100 miles from Pensacola and 285 miles from the Tampa Bay area, will be open for oil company bids. Chevron also is pressing for federal permission to drill in the Destin Dome area south of the Florida Panhandle.
The Minerals Management Service of the Department of the Interior is proposing 20 lease sales in offshore U.S. waters during the next five years. The service says that in the next 20 years the nation's oil consumption will rise 33 percent, natural gas needs will grow more than 50 percent and demand for electricity will rise 45 percent.
The Marine 4 blowout came about 4:15 a.m. on Friday the 13th.
The rig, owned by Marine Drilling Co., was drilling an exploratory well for Applied Drilling Technology Inc., a subsidiary of Global Marine, a major international offshore drilling contractor.
Coast Guard investigator Johnson said crew members reported that they were drilling to a known deposit of natural gas but broke into it with the drill bit "13 or 14 feet before they expected to."
The crew had stopped drilling to attach another section of pipe, he said, when gas began to flow unexpectedly up the pipe. The crew tried to stop the flow by closing a valve at the top of the pipe, but a piece of the valve broke, Johnson said.
"Suddenly, hot mud (from 150 to 200 degrees) and gas began shooting everywhere," Johnson said, and a decision to evacuate the rig came almost immediately.
One man, Ben Freeman, 61, who helped 39 workers into escape pods, is missing and presumed dead.
"Blowouts are rare events," said Michael Dawson, Global Marine spokesman. "In ADTI's 21-year history, there has been only one other well-control incident like this."
In the next few days, efforts to contain the Marine 4 blowout will continue on two fronts:
A second drilling rig, Marine 304, has been brought to the scene -- upwind, to avoid the flammable gas -- and has begun drilling a "relief well" 1,500 feet from the damaged well.
The relief well is being drilled at an angle, toward the damaged well. Magnetic sensors are being used to guide the drill bit. The relief well will meet the damaged well about a mile below the ocean floor.
When the relief well meets the damaged well, it will turn and follow the damaged well to its bottom. At that point, heavy mud and cement will be injected, plugging both wells, Dawson said.
Drilling the relief well could take weeks, so a second, more dangerous effort will begin in the next few days.
A small crew wearing metal-free clothing and using non-electric equipment will board the rig and attempt to cut away the equipment at the top of the pipe where gas is escaping. When the top of the pipe is exposed, a bore cap will be lifted by crane and set atop the pipe, stopping the flow of gas.
It is extraordinarily dangerous work.
To prevent sparks, workers will cut the pipe with a "sand cutter," a tool that blasts sand and water though a quarter-inch nozzle at 13,000 pounds per square inch.
"I've used it to cut through steel 4 inches thick," said Richard Hatteberg, engineer for Boots & Coots International, a company that specializes in controlling gas well blowouts and fires.
Environmental effects of the Marine 4 blowout are minimal, Johnson said.
"Initially there was a light sheen on the water," he said, "but it dissipated almost immediately. The gas will dissipate in the atmosphere, and there should be no long-term environmental effect."
Enid Sisskin, legislative chairwoman of West Coast Environmental Defense, a Pensacola organization, acknowledged that a gas release is not the environmental threat that leaking crude oil would be.
But, she said, "just because you don't see oil on a bird doesn't mean bad things aren't happening. There are issues involving air pollution and toxicity to fish and other creatures far around each well head.
"We'll have to watch this one and see how long it runs," she said.
- David Ballingrud covers science issues for the St. Petersburg Times. He can be reached at 727-893-8245 or email@example.com.
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