Oil Update: Citi Is Upgrading The Shale Services Sector By: Benzinga via Benzinga December 11, 2015 at 13:28 PM EST Citi has upgraded the U.S. oil services sector to Buy. The firm is intentionally getting in early on the trade based on the ... Read More >> Related Stocks: Baker Hughes Inc Halliburton Co Helmerich & Payne Nabors Industries Natl Oilwell Varco Patterson-Uti Energy Superior Energy Services Weatherford International Ltd iPath Dow Jones-Goldman Sachs Crude Oil Fund