China Petroleum and Chemical Corp, the world's largest refiner by volume, has signed a deal with China National Offshore Oil Corp, China's largest producer of offshore oil and gas, to study and explore several mostly offshore areas in China.

The agreement will cover three years of joint study, joint exploration and facility sharing in multiple sea areas.

The two oil and gas giants will share data and carry out joint studies in the Yellow River Mouth Sag, Qingdong Sag and the eastern part of Bodong Sag in the Bohai Basin, as well as the southwestern Weizhou and Xuwen areas of the Beibu Gulf Basin, North Jiangsu Basin and blocks in the eastern South Yellow Sea Basin.

The agreement covers 19 prospecting rights and an area of approximately 26,900 square kilometers.

Considering the rich oil and gas resources in the country and low levels of exploration, offshore oil and gas is an area of significant potential in China.

The two companies have said they will share information, technologies and facilities to jointly develop offshore oil and gas reserves.