China continues to spread its wings in a quest for pieces of the world's natural resources. And it's now looking more and more like the world's most populous nation could soon be operating in our own backyard -- or at least our hemisphere.

According to Tuesday's Wall Street Journal, two Chinese oil companies -- China National Petroleum Corp. (CNPC), the state-owned parent company of PetroChina (NYSE:PTR), and CNOOC (NYSE:CEO), China’s biggest offshore operator -- are willing to ante up no less than $17 billion for YPF -- or specifically, Spanish oil company Repsol's (NYSE:REP) stake in the Argentine assets.

Repsol has been trying to reduce its 84% stake in YPF to pay down debt. Two years ago, it sold 14.9% of its YPF holdings to Grupo Peterson, an Argentine firm, for $2.24 billion. In the meantime, Repsol has met with success in Brazil's deepwater Santos basin, in part as a partner of Petrobras (NYSE:PBR), the Brazilian state oil company. But like essentially all oil companies, its second quarter was not pretty, coming in with earnings 62% lower than the comparable quarter a year ago.

China's biggest international deal thus far was the $14 billion it paid last year through Aluminum Corp. of China (NYSE:ACH) -- in concert with Alcoa (NYSE:AA) -- for 9% of mining giant Rio Tinto (NYSE:RTP). This year, it attempted to double that stake by investing $19.5 billion in the company, but was ultimately rebuffed.

It appears that no formal offer has as yet been made for YPF. Nevertheless, should a bid be made as expected, it would only strengthen a trend of Chinese companies working together, rather than alone, as in the past. It was also noteworthy last month when China Petrochemical Corp. -- Sinopec to its friends -- teamed up with CNOOC to purchase a portion of Angolan assets owned by Houston-based Marathon Oil (NYSE:MRO).

Although Warren Buffett no longer holds a sizable position in PetroChina, I believe that the company and CNOOC both bear continued watching. As China's active pursuit of natural resources continues, it may pay to have some skin in the game.

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Fool contributor David Lee Smith doesn't own shares in any of the companies mentioned above. He does welcome your questions or comments. Petroleo Brasileiro is a Motley Fool Income Investor recommendation. Try any of our Foolish newsletters today, free for 30 days. The Motley Fool will never sell out on its disclosure policy.