UPDATE 1-Oil providers ask Venezuela's PDVSA for cargo prepayments -sources

Nov 19 Big oil suppliers have started requiring prepayment when selling cargoes of crude and refined products to Venezuela's PDVSA, in an effort to limit potential risks from the state-run company's well-known cashflow woes, five sources from firms involved in the deals told Reuters. 

http://www.reuters.com/article/2015/11/19/oil-pdvsa-debt-idUSL1N13E2QF20151119#pV6cKUCQf6YCKKD9.97