By Marianna Parraga HOUSTON, Feb 25 (Reuters) – A 655,000-barrel cargo of Venezuelan heavy crude chartered by a unit of Italy’s Eni SpA ENI.MI departed on Friday from a port operated by state-run PDVSA,shipping data showed, marking Venezuela’s first export to Europe after a three-month pause. Eni and Spain’s Repsol SA REP.MC last year received U.S. authorizations to take Venezuelan oil to Europe as compensation for outstanding debt in an easing of American sanctions on Venezuela’s oil industry....