China National Petroleum Corporation (CNPC) and the Aluminum Corporation of China Limited (Chalco) have signed a strategic cooperation agreement to expand the areas in which they work together.
In March, the two companies formed a joint venture, which has recently gained its business license, according to CNPC.
The two sides will cooperate on fuel supply, the application of non-ferrous metals and international trade.
CNPC is China's largest oil and gas producer and supplier, while Chalco is the country's top aluminum producer.
Earlier data showed net profits made by PetroChina, the listed arm of CNPC, totalled 5.7 billion yuan (about 828.5 million U.S. dollars) in the first quarter.
Chalco made 920 million yuan in net profit in the first three months, nearly four times the amount in the same period last year.