The top U.S. buyers of Venezuelan oil are in the unusual position of trying to return millions of barrels of crude they need but cannot accept because of U.S. sanctions on the South American nation and its state-run energy firm PDVSA. FPDVSA’s U.S. refining subsidiary Citgo Petroleum Corp and Valero Energy are proposing to return 2 million barrels of crude loaded before sanctions, while a third U.S. oil company, Chevron Corp, has sought so far unsuccessfully to legally pay for 4.3 million barrels, according to an internal PDVSA document seen by Reuters. In effect, more than 6 million barrels of Venezuelan crude remain in limbo as a result of U.S. sanctions imposed on Jan. 28 by Washington in an effort to oust […]