* Police say Chevron reports do not match reality of spill
* Leak estimated up to 650 barrels, cleanup under way
* Energy Ministry could take legal action against Chevron (Adds police investigating depth of drilling by Chevron, comments throughout)
By Sabrina Lorenzi and Brian Ellsworth
RIO DE JANEIRO, Nov 17 (Reuters) - Brazilian federal police have opened a probe into U.S. oil giant Chevron <CVX.N> over alleged pollution linked to an oil spill at its offshore Frade project.
Fabio Scliar, who heads the Federal Police's division of environment and historical patrimony, told Reuters that early evidence showed Chevron's drilling went about 500 meters (1,515 feet) beyond permit. Information provided by Chevron to the police does not match what police saw upon a visit to the site, he added.
"After that, the seabed fractured, and a crack of about 300 meters opened," Scliar said in an interview.
Brazil's energy regulator ANP said oil seeps off the coast of Rio de Janeiro were caused by a well drilled by Chevron at Frade, where the company has estimated as much as 650 barrels had been released causing a "sheen" on the sea surface.
Energy Minister Edison Lobao told reporters in Brasilia on Thursday that the leak "is not good, but neither is it as grave as is being said."
He said the ANP, which is investigating the leak, could take legal action against the company if there are grounds for it and warned that Chevron would be held to account for any breaches of conduct. Lobao did not express any specific complaint against Chevron however.
"If Chevron is not doing its part, it will be severely punished," Lobao said.
In an e-mailed response to Reuters' questions about the investigation, a Chevron spokesman said the company "continues to fully inform and cooperate with Brazilian government agencies as part of the company's response efforts."
Calls to the federal police offices in Rio de Janeiro about the case went unanswered.
The company on Tuesday said it had started plugging the well that was suspected of causing the oil seeps and that the seeps appeared to have stopped.
On Sunday, Chevron said the sheen has spread over 163 square kilometers (63 sq miles) from the well area. The company has vessels in the area working to either recover or disperse the oil.
Brazil is sitting atop massive deep-water oil reserves that were discovered over the past half decade. The government is keen to tap these resources as a new source of revenue for federal, state and municipal governments.
But the Deepwater Horizon drilling rig that exploded in April 2010 in the U.S. Gulf underscores the risks that offshore exploration and production poses for Brazil's extensive coastal economy.
(Additional reporting by Luciana Lopez and Guillermo Parra-Bernal in Sao Paulo and Leonardo Goy in Brasilia; Editing by Peter Murphy and Marguerita Choy)