April 27 (Reuters) - Shares of oilfield services provider Liberty Oilfield Services soared on Wednesday after topping Wall Street earnings estimates and issuing an optimistic outlook for the shale-oil services market. Liberty’s shares were trading at $11.81 mid-morning, up nearly 10%. Benchmark U.S. oil prices also climbed 2.5% to $64.47 on a smaller-than-expected increase in crude oil inventories that was bullish for demand. (Reporting by Liz Hampton in Denver and Rithika Krishna in Bengaluru; Editing by Lisa Shumaker)