First Cuba offshore well going slowly, mid-May finish seen
* Sources say Repsol encouraged by findings so far
* Cuba says five wells to be drilled in 2012-2013
* Cuba dependent on Venezuela, Chavez for oil
By Jeff Franks
HAVANA, April 13 (Reuters) - Drilling of the first well in the long-awaited exploration of Cuba's offshore oilfields has gone slower than expected, but should be completed by mid-May, sources close to the project said on Fri day.
They said drillers had encountered harder rock beneath the sea bed than expected, which combined with other minor problems, had slowed progress.
When drilling began on Feb. 1, Spanish oil giant Repsol YPF said the average deepwater well takes 60 days to complete, but that many drag on much longer, depending on conditions.
A Repsol spokesman could not confirm on Friday the projected mid-May completion date.
This well, which is in 5,600 feet (1,706 metres) of water off the communist-run island's northwest coast, is the first of five currently planned, Cuban officials say.
Cuba has said it could have 20 billion barrels in its offshore fields. It needs the oil to end its dependence on Venezuela, which ships it 114,000 barrels a day.
Cancer-stricken Venezuelan President Hugo Chavez is Cuba's top ally, but island leaders worry that the oil flow could stop if he dies or loses his bid for re-election later this year.
The U.S. Geological Survey estimated Cuba may have 5 billion barrels of oil and 10 trillion cubic feet of natural gas offshore, but its study covered only part of the Cuban zone.
Various sources said Repsol has been encouraged by its findings thus far, but the company has said results will not be known until the well is finished and studies are conducted.
Oil experts say it will take three years or more to bring the Cuban oil on line, if enough is found to justify production.
After Repsol completes its well, it will hand the Scarabeo 9 drilling rig over to Malaysia's state-owned Petronas and its Russian partner Gazprom Neft for a second well.
Then it will go back to Repsol, which has a consortium with Norway's Statoil and ONGC Videsh, a unit of India's ONGC, for another well.
The massive, Chinese-built rig, which is more than 20 miles (32 km) offshore but visible from Havana, is being leased from owner Saipem, a unit of Italian oil company Eni .
Due to the longstanding U.S. trade embargo against Cuba, no American oil companies are involved in the project.
Repsol drilled a well in Cuban waters in 2004 and found oil, but said it was not commercially viable. Technological limitations imposed by the embargo made it difficult to find another rig for work in Cuba, industry sources have said.
The project has raised environmental concerns in the United States, particularly in Florida, which is 90 miles (145 km) north of Cuba and fears its shores could be damaged if there is an accident similar to the BP oil spill in the Gulf of Mexico in 2010.
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