China Petrochemical Corp (Sinopec Group) is in talks with Repsol-YPF, Spain's largest oil company, to buy out the latter's stake in Argentinean oil unit, YPF, a source close to the deal disclosed Tuesday, Global Times reported.

The two sides have already reached a $15 billion non-binding purchase agreement, the source added.

YPF is now 57.4 percent owned by Repsol-YPF. Sinopec's purchase of this stake has got approval from Repsol's board of directors. However, the governments of Spain and Argentina need to give their nods as well, the newspaper said.