April 14 (UPI) -- The government of Venezuela signed an agreement with U.S. oil company Chevron Corp. that will allow it to increase its participation in key projects and expand production in the Orinoco Belt, the country's main oil-producing region. Venezuelan authorities confirmed the agreement Monday, and it raises Chevron's stake in the joint venture Petroindependencia to 49% from 35.8% , giving it greater control over operations in an area where extra-heavy crude is produced. In addition,