Brazilian state-controlled oil company Petróleo Brasileiro SA could take a charge of about 52 billion reais ($20 billion) in its delayed third-quarter results to reduce the value of some assets, a Veja magazine blog said on Monday. The impairment equals 42 percent of the market value of Petrobras (PETR4.SA), as the company is known, Veja’s Mercados blog said, citing sources close to the company. Petrobras faces limited access to financial markets as a result of the scandal and falling oil prices.