In energy ETFs, the United States Oil Fund ( USO ) was up 2.5% at $9.61 while the United States Natural Gas ETF ( UNG ) was up 2.9% at $6.70. Energy shares were mostly higher as Thursday's regular session ended, with crude oil prices , as well as gasoline prices, surging higher following Energy Secretary Rick Perry's comments to media reporters, saying that 30% of production at Texas refineries is off line in the wake of Tropical Storm Harvey. Light, sweet crude oil for October delivery was up 2.4% at $47.05 per barrel.