Insolvent Swiss oil refiner Petroplus owes Algerian state energy firm Sonatrach over $250 million in unpaid bills, an Algerian energy sector official told Reuters. Sonatrach has not received payment for several cargoes of crude it delivered to the refiner, the source said, without specifying what action, if any, the Algerian firm planned to take to recover the money. Late last year, Petroplus said lenders had frozen a credit facility which it was using to buy crude for delivery to its refineries. It filed for insolvency protection in January. A lawyer whose firm has been appointed as liquidator for Petroplus entities in Switzerland declined to comment on any unsettled bills with Sonatrach. Petroplus has been divesting assets since it became insolvent. It sold its Cressier plant, one of only two refineries in Switzerland, to a joint venture between Vitol, the world's largest oil trader and Atlas, run by Petroplus co-founder Marcel Van Poecke, earlier this month. Read more.