China National Offshore Oil Corporation (CNOOC), China's largest offshore oil producer, is to step up deepwater exploration of oil and gas resources, while developing clean and low-carbon energies, company president Fu Chengyu said Monday.

"CNOOC aims to transform its economic development mode via technological innovation. Its exploitation of offshore oil resources will shift from shallow waters to waters as deep as 3,000 meters," Fu said in an interview with Xinhua.

Oceans are estimated to hold about one third of the world's petroleum and natural gas resources and they are likely to replace terrestrial and inshore regions as the world's major depositories of oil and gas resources, according to CNOOC.

CNOOC had invested more than 15 billion yuan (2.19 billion U.S. dollars) in building deep-water drilling vessels, deep-water lifting and pipe-laying barges as well as deep-water geographical survey vessels, Fu said.

Once operational in 2011, such investment would significantly enhance China's capacity to explore and develop deep-water petroleum and gas resources, he said.

In 2006, CNOOC and its partner, Canada-based Husky Energy, discovered China's first deep-water gas field Liwan 3-1 in the Pearl River Mouth Basin located at the eastern region of South China Sea.

Between 2009 and 2010, two more deep-water gas fields were found in the same sea waters by CNOOC and Husky Energy.

The first-stage project of Liwan 3-1 was expected to start production in 2013.

CNOOC also planned to increase its investment in new energy fields, such as wind power and coal-based clean energy, to more than 10 billion yuan (1.46 billion U.S. dollars) in the next three years, Fu said.

The company's wind power plants are under construction on the sea and in areas like Inner Mongolia Autonomous Region, northwest China's Gansu Province, and south China's Hainan Province. It has also begun development of bio-diesel and electric vehicle battery technologies.

Liquified natural gas (LNG) played an important role in CNOOC's strategy of developing clean, low-carbon energy, Fu said.

The company had signed long-term supply contracts with domestic and overseas partners for 320 million tonnes of LNG, an equivalent of importing 22 billion cubic meters of LNG annually for 25 years.