HOUSTON - The world's largest oil trader Vitol SA has secured a second cargo of U.S.-produced crude for export, just weeks after the U.S. government lifted the ban on exporting domestic oil. Producer ConocPhillips said it will sell crude and condensate produced in the Eagle Ford shale of Texas to Vitol. The cargo will load out of NuStar's North Beach terminal in Corpus Christi on Dec. 31, NuStar said in a statement. Last week, Enterprise Products Partners said it would provide logistics and terminaling services for Vitol to load a 600,000 barrel cargo of domestic light crude in the first week of January. With U.S. crude futures trading near parity or at a premium to the Brent benchmark in the past week, some traders are questioning the economic viability of such exports. On Wednesday, U.S. West Texas Intermediate benchmark futures settled at a 14-cent a barrel premium to Brent. The highly visible trade by the privately held merchant comes as a tough year for commodity shops including Noble Group Ltd and Glencore PLC draws to a close with prices of raw materials from oil to copper languishing at multi-year lows.