The JV will refine the crude oil supplied by CNPC and export all the refined oil back to China. Nippon Oil will be the JV's operator.
Further details are not disclosed.
Osaka-based Nippon Oil is Japan's largest petroleum importer and refiner with capability of over 1.3 million barrels per day. It has been working with CNPC since 2004.
Beijing-based CNPC has been speeding up its expansion overseas.
At the end of June, it won the deal with British energy company BP to develop Iraq's largest oil field Rumaila. In May, CNPC bought 45.1 percent stake in Singapore Petroleum Company with US$1 billion.
The company is also reportedly
eyeing Spain's oil major Repsol YPF, S.A's assets in Argentina. If the US$14.5 billion deal gets approved, it will be the largest ever M&A in China.