UPDATE 7-Venezuela gas rig sinks in Caribbean, no leaks
* Second platform to sink in less than a month
* All workers safe, captain dives off sinking rig
* Aban Pearl rig was exploring Mariscal Sucre gas field (New throughout, updates with new comments from Ramirez)
By Frank Jack Daniel and Marianna Parraga
CARACAS, May 13 (Reuters) - A Venezuelan natural gas exploration rig sank in the Caribbean sea on Thursday, less than a month after a deadly explosion in the Gulf of Mexico destroyed a BP-owned oil rig and created a natural disaster.
Most of the 95 workers escaped by boat after water apparently rushed into one of the giant submarine rafts suporting the football field-sized structure. The captain and three engineers stayed to try and fix the $200 million rig. They dived to safety just as it lurched into the waves.
There was no gas leak or threat to the environment, the government said.
Energy Minister Rafael Ramirez said the well being explored by the Aban Pearl rig had been safely sealed, and he rejected any comparisons to the BP (BP.L) accident, which killed 11 people and triggered one of the world's worst oil spills.
"This is different from the Gulf of Mexico, because it is a testing well," Ramirez told Reuters. [ID:nN1360255]
He flew to the site near Trinidad and Tobago on Thursday: "The rig sank completely ... there is nothing to see."
The Aban Pearl was the first offshore gas rig operated by state oil company PDVSA, and state television frequently portrayed it as evidence of Venezuela's engineering prowess.
Venezuela has been producing oil for more than a century, almost all of it from onshore or the inland Lake Maracaibo. Offshore drilling, especially deep water production, is expected to provide more of the world's oil supply as production in onshore fields declines while demand rises. <^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
For timeline of major offshore accidents: [ID:nN13272386]
For factbox of incidents involving PDVSA: [ID:nN13153698] ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^>
The BP spill has prompted a push for tighter offshore drilling regulations in the United States, and Venezuela's accident could bring further scrutiny to offshore exploration. Many experts said the second major rig collapse in two months was likely to renew criticism of PDVSA's operational record.
"This is adding PR insult to injury," Tyler Priest, director of global studies at the Bauer College of Business, University of Houston, and author of a book about Shell's offshore Gulf of Mexico activities.
CHAVEZ 'TWEETS' NEWS
President Hugo Chavez broke news of the accident at the rig -- owned by India's Aban Offshore (ABAN.BO) in alliance with Singapore-based Petromarine Energy Services Ltd -- at 3:11 a.m. (0741 GMT) from his Twitter account, @chavezcandanga.
Critics say Chavez wrecked PDVSA by firing thousands of managers and technicians after a strike in 2002. The company. the main financer of his socialist revolution, has suffered cash flow problems on lower oil prices.
Venezuela, one of the world's leading oil exporters, has endured fires and maintenance problems at its network of refineries in recent years. Nationalization of foreign-owned projects, new foreign investments and higher taxes have bolstered PDVSA's coffers.
The Latin American OPEC nation sits on some of the world's largest offshore natural gas reserves, but PDVSA is not yet producing offshore gas. Fears of rule changes and pricing issues mean the company has struggled to attract extraction investment from foreign companies with the right experience.
Ramirez said submersible robots would probe the cause of the accident, which appeared to be a sudden surge of water into one of the submarine rafts that the rig's legs float on.
He said safety valves and other mechanisms have sealed the well, with no risk of a leak. The rig owner would likely try to refloat it, and two more exploration rigs are traveling to Venezuela from India, he said. Aban Offshore's shares fell by 1.51 percent to 1017.35 rupees on Thursday.
The minister said the accident would not affect the project, and he expected the first gas production in 2012.
"There are several hypothesis about the cause but nothing has been proved yet," the minister said. "We believe that in two months we should have an operating platform in place."
The Aban Pearl rig was built in 1977 and last changed hands in 2007 for around $211 million. The semisubmersible rig was drilling some of the 16 gas wells in the Mariscal Sucre natural gas project. Last week, Ramirez visited the platform to celebrate the end of early tests at the well, called Dragon 6.
Last year, PDVSA and Spanish giant Repsol (REP.MC) said they had found a vast offshore gas field in Venezuelan waters [ID:nLB110788]. Then in April, Venezuela gave Chevron (CVX.N) the go-ahead to extract gas from a 7 trillion cubic feet project off the Orinoco Delta [ID:nN08181656], but Chevron says it will not extract gas from there for at least a few years. (Additional reporting by Josh Schneyer in New York, Brian Ellsworth in Rio, Alonso Soto in Santiago and Bruce Nichols in Houston; Editing by Daniel Wallis and David Gregorio)