They were to launch a $20 billion venture between Russian firms and Venezuelan state company PDVSA to pump 450,000 barrels a day — almost a fifth of the OPEC member’s current output — from the vast Orinoco heavy oil...

Power rationing since late 2009 has emerged as a major problem for the OPEC member nation of nearly 29 million people, threatening its ability to pull out of recession and weighing on Chavez’s popularity ahead of a September legislative...