Venezuelan state-run oil company PDVSA has bought two 1-million barrel cargoes of Nigerian crude from Royal Dutch Shell in the past month to be used as diluents for its extra heavy oil, traders told Reuters. Venezuela, which has the world’s largest crude reserves, began importing a variety of crudes for the first time last year, using them to dilute the OPEC nation’s heavy grades in order to reduce costs and create better blends for customers. PDVSA imported some 4 million barrels of Algerian Saharan Blend crude from October to January under a supply contract with state-owned Sonatrach during the maintenance of a heavy-crude upgrader, which it says saved $10 to $20 a barrel. It is also buying Russian Urals crude for its Isla refinery and a storage terminal on […]