US oil operators have brought back online 3.4 million barrels per day of the estimated 4 million bpd that were shut in during last week's cold blast, according to S&P Global Platts Analytics North American supply analyst Parker Fawcett. Production is still down in the Permian and Anadarko basins, the SCOOP-STACK and Texas Gulf Coast, while Colorado's Denver-Julesburg Basin, North Dakota's Bakken Shale and Wyoming's Powder River Basin are "fully back," Fawcett said.