A Brazilian prosecutor plans to file criminal charges against Chevron...and some of its local managers within weeks, adding the threat of prison sentences to an $11 billion civil lawsuit as punishment for a November offshore oil spill…[It] will likely include a request for criminal indictment of George Buck, chief executive of Chevron's Brazil unit, as well as other staff…Transocean…are also expected to be charged…Chevron's legal troubles come as new oil rules give Brazil's government more control over the country's vast oil wealth…Chevron…said…"...that the charges are without merit"…Transocean…declined to comment…Brazilian prosecutors have become more active in going after alleged polluters…The…Federal Police investigator submitted a report saying Chevron and Transocean took "unacceptable" risks…Chevron says that there is no evidence the Frade leak...has had any impact on aquatic life or on humans. [also refers to BP, Petrobras]