Advisers to China’s Sinopec have offered its oil assets in Argentina to about a dozen potential suitors, three sources familiar with the matter told Reuters, as losses and labor headaches prompt Asia’s largest refiner to pull out. The Argentine oil and gas assets, mainly in the southern province of Santa Cruz, could be worth $750 million to $1 billion, one of the sources said. That would be less than half the $2.45 billion Sinopec paid in 2010 to buy the Argentine assets from US-based Occidental Petroleum Corp, marking an aggressive drive to diversify its oil sources at the time. Prospective buyers for the assets – mainly large energy companies from the United States, Europe, Africa and Latin America – include Angola’s state oil company Sonangol and two Russian energy giants, including Rosneft, said two of the sources. Mexico’s Vista Oil & Gas has also expressed an interest, according to a separate source. There could be more than 15 prospective suitors.