No injuries were reported in the midmorning blowout and there was no fire as of Tuesday evening at the site, about 55 miles off the Louisiana coast in the Gulf of Mexico.
Experts from Wild Well Control Inc. were to assess the well site overnight and develop a plan to shut down the flow of gas, said Jim Noe, executive vice-president of Hercules Offshore Inc, owner of the drilling rig where the blowout occurred.
Noe stressed that gas, not oil, was flowing from the well. He said it's an important distinction because gas wells in relatively shallow areas — this one was in 154 feet of water — sometimes tend to clog with sand, effectively snuffing themselves out. "That is a distinct possibility at this point," he said. "But until we have our Wild Well Control personnel on the rig, we won't know much more."
The Coast Guard and the Bureau of Safety and Environmental Enforcement, or BSEE, kept state and coastal officials apprised of the well's status.
"According to federal officials, there is no imminent danger at this time," said Kevin Davis, head of the Louisiana governor's homeland security office said.
Still, the Coast Guard kept nautical traffic out of an area within 500 metres of the site, where the spewing gas posed a fire hazard. The Federal Aviation Administration restricted aircraft up to 2,000 feet above the area. BSEE said a firefighting vessel with water and foam capabilities would reach the scene by Tuesday night.
BSEE said inspectors flying over the site soon after the blowout saw a light sheen covering an area about a half-mile by 50 feet. However, it was dissipating quickly.
Earlier this month, a gas well flowed for several days before being sealed off the Louisiana coast.
In 2010, an oil rig exploded off the state's coast, leading to a blowout that spewed millions of gallons of oil into the Gulf in the worst offshore disaster in the United States.
Coastal officials stressed that Tuesday's blowout was nothing of that magnitude.
Chris Roberts, a member of the Jefferson Parish Council in south Louisiana, said the travel restrictions might pose an inconvenience for participants in an upcoming deep sea fishing tournament.
"It could change some plans as to where some people plan to fish," he said.
Tuesday's blowout occurred near an unmanned offshore gas platform that was not currently producing natural gas, said Eileen Angelico, spokeswoman for the bureau. The workers were aboard a portable drilling rig known as a jackup rig, owned by Hercules, which was a contractor for exploration and production company Walter Oil & Gas Corp.
Walter Oil & Gas reported to the BSEE that the rig was completing a "sidetrack well" — a means of re-entering the original well bore, Angelico said.
The purpose of the sidetrack well in this instance was not immediately clear. A spokesman for the corporation didn't have the information Tuesday night. Industry websites say sidetrack wells are sometimes drilled to remedy a problem with the existing well bore.
"It's a way to overcome an engineering problem with the original well," Ken Medlock, an energy expert at Rice University's Baker Institute said. "They're not drilled all the time, but it's not new."
Associated Press reporter Ramit Plushnick-Masti in Houston contributed to this story.