Oil prices seesawed in volatile trading on Wednesday, barely hanging onto a third day of gains after government data showing a large U.S. crude inventory build surprised traders the morning after an industry group had reported a draw. The U.S. Energy Information Administration (EIA) said domestic crude inventories rose 3.1 million barrels last week, more than the 2.2 million-barrel build that analysts had forecast in a Reuters survey. Just on Tuesday preliminary inventory data by the American Petroleum Institute had suggested a drawdown of 1.2 million barrels. Oil prices slid after the EIA report. Brent, the global crude benchmark, was up 25 cents at $52.17 a barrel by 12:22 p.m. EDT (1622 GMT). At its session high, Brent was up more than $1, and then it turned negative before edging slightly higher. The West Texas Intermediate (WTI) benchmark for U.S. crude was down 5 cents to $48.48 a barrel. It had also been up more than $1 at its session high. Between Friday and Tuesday, Brent and U.S. crude prices had rallied about $4 each, breaking above a month-long trading range on technical buying and supportive data. The crude build “will take some of the wind out of the market’s sails”, said Gene McGillian, senior analyst at Tradition Energy in Stamford, Connecticut.