* All 13 crew members safely off the platform
* Oil sheen not seen on water, Coast Guard says
* Facility was not actively producing oil or gas
* Automated equipment shut off the flow of oil and gas (Recasts, adds information from Mariner about accident, accident impact on crude oil market and share prices)
By Kathy Finn
NEW ORLEANS, Sept 2 (Reuters) - An oil and gas platform operated by Mariner Energy ME.N burst into flames in the Gulf of Mexico on Thursday, but the crew of 13 escaped and there were no signs of an oil spill, the U.S. Coast Guard said.
"The boats and the aircraft on scene cannot see a sheen," U.S. Coast Guard Captain Peter Troedsson told a news conference in New Orleans.
Initially, Mariner reported there was a mile-long oily sheen on the water around the platform, according to the government.
Reuters Insider video on market overreacting to fire
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Factbox on comparisons between Mariner and BP accidents
Graphic on Mariner Energy platform fire:
The fire burned for several hours before it was extinguished. A company spokesman said it started on an upper deck of the platform where living quarters were located, and had not been caused by a "blowout," or sudden release of oil and gas from a well.
The crew, plucked from the Gulf by an oil supply vessel, was transported to a hospital onshore and no injuries have been reported, the Houston-based company said.
Automated shutoff equipment turned off the flow of oil and gas from the platform's seven producing wells as the crew evacuated, Mariner said.
The cause of the fire is still unknown and under investigation, the company said.
"It's unlikely to have long-term implications for production in the Gulf of Mexico," said Raoul LeBlanc, a senior director at PFC Energy in Houston.
Nevertheless, the accident brought unwelcome attention to the offshore drilling industry as it is trying to roll back a six-month deepwater drilling moratorium imposed in the wake of the BP Plc (BP.L)(BP.N) Macondo well disaster, which killed 11 workers and poured 4.1 million barrels of oil into the Gulf.
Environmental groups said the Mariner explosion reinforced the need to keep the moratorium in place. White House spokesman Robert Gibbs said he did not know whether the fire would affect the moratorium, scheduled to expire Nov. 30.
Several analysts said the accident could hurt the industry in its court battle to lift the drilling halt early.
"The incident has happened at the wrong time," said Eugen Weinberg, head of commodity research at Commerzbank. "The political establishment will probably move quickly as everybody still remembers the slow dealing with the Macondo accident and the dramatic pictures from this summer."
The platform is located more than 90 miles (145 km) south of Louisiana's Vermilion Bay, 200 miles west of BP's ruptured Macondo well. It is in relatively shallow water 340 feet (104 meters) deep.
The platform's output is a small fraction of the 1.6 million barrels of oil and 6.4 billion cubic feet of gas the region produces on a daily basis.
The facility averaged 9.2 million cubic feet of natural gas per day and 1,400 barrels of oil and condensate per day during the last week of August, Mariner said.
News of the fire helped push crude oil prices up $1.11 to $75.02 a barrel on the New York Mercantile Exchange. Oil prices were also boosted by Hurricane Earl, which is threatening refineries along the U.S. East Coast.
Shares of Mariner Energy fell 2.6 percent to close at $22.75 and shares of Apache Corp (APA.N) , which is expected to buy Mariner Energy in a $2.7 billion deal, fell 1.3 percent to close at $91.30.
Apache plans to proceed with the Mariner purchase, Apache spokesman Bill Mintz, said.
Mariner has participated in at least 35 deepwater projects in the Gulf and operated over half of them.
The fire was the fifth reported at offshore sites operated by Mariner since October 2006, according to the U.S. Bureau of Ocean Energy Management, Regulation and Enforcement.
None of the earlier fires caused any fatalities, although workers were injured in two of the accidents. The company also suffered a blowout while drilling a well about 90 miles off the Louisiana coast in May 2008, but the well was brought under control within a few hours. (Additional reporting by Kristen Hays, Bruce Nichols, Erwin Seba and Eileen O'Grady in Houston; David Sheppard, Matt Daily and Joshua Schneyer in New York; Tom Doggett, Ayesha Rascoe and Timothy Gardner in Washington; writing by Anna Driver and Andy Sullivan in Washington)