Brazil's state-run oil firm Petrobras will do what it can to reduce the reinjection of natural gas into oil wells, Chief Executive Magda Chambriard said on Wednesday.The government published a decree on Monday authorizing the oil regulator ANP to order oil companies to reduce the reinjection to increase the supply of gas and lower prices.The rule will apply only to new wells, said Mines and Energy Minister Alexandre Silveira at the time…