World's First Large-Scale Offshore Ultra-Heavy Oilfield Starts Production

The Lyuda 5-2 North Oilfield of China National Offshore Oil Corporation (CNOOC), the world's first large-scale offshore ultra-heavy crude oil thermal recovery oilfield, was put into production on April 23.

The oilfield is expected to promote development of ultra-heavy oil resources in the Bohai Sea.

Located in the Liaodong Bay area of the Bohai Sea, the Lyuda 5-2 North Oilfield has an average water depth of about 29.4 meters. The project is expected to realize a peak annual output of 400,000 metric tons of crude oil in 2024.

Once fully operational, it is estimated that more than 6.5 million tons of crude oil could be produced from the oilfield. That output is enough to create asphalt for construction of a 5,000-kilometer 4-lane highway.

The production capacity will play a crucial role in increasing output of the Bohai oilfield to 40 million tons.

A view of the crude oil development facility at Lyuda 5-2 North Oilfield in Bohai Sea [Photo/sasac.gov.cn]

Heavy oil refers to a relatively viscous crude oil with poor fluidity that has low yield.

The crude oil developed from the Lyuda 5-2 North Oilfield is an unconventional heavy oil with a formation viscosity of more than 50,000 milliPascals, over 20 times that of the thickest crude oil ever developed in the Bohai Sea. In other words, the crude oil is like solid asphalt when at normal temperature.

At present, the proven reserves of such unconventional heavy oil in the Bohai oilfield exceed 600 million tons, accounting for 14.5 percent of the total proven geological reserves in the Bohai Sea.

Development of the heavy oil is key to improved output.

Wang Benwu, deputy general manager of CNOOC's subsidiary in Liaodong Bay, said that the company has developed several technologies and facilities and made operation plans such as an injection-production integrated pattern under high temperature and high-temperature well security controls that support crude oil development of the Lyuda 5-2 North Oilfield.

(Executive editor: Niu Yilin)