China is considering using carbon capture and storage (CCS) technology to enhance oil recovery at oilfields in Beibu Gulf of the South China Sea.
Guangdong Laboratory is researching a scheme to capture carbon dioxide from onshore power plants and reinject it into offshore reservoirs to increase oil production, deputy director of Nanfang Science and Engineering Li Xusheng told attendees of the Offshore China conference in Shenzhen.
The current focus of the study is to capture CO2 emitted from the Datang Leizhou power plant and reinject it into reservoirs at the Wushi oilfield, which is under development in the Beibu Gulf.
Li, the former vice president of CNOOC Zhanjiang in charge of the Wushi development, said the scheme will be able to store 15 million tonnes of CO2 and enhance oil recovery by 2 million tonnes.
The power plant — operated by one of China’s largest power utilities, Datang Group — has two units each of 1 gigawatt capacity and has been operational since 2020.
The Guangdong government has endorsed Datang’s plan to double the power generation capacity to 4GW.
Li said a wider plan calls for the capture of CO2 emitted from seven other power utilities and petrochemical complexes in eastern Guangdong province and its reinjection at other South China Sea fields.
This will be CNOOC Ltd’s second offshore CCS-EOR project. The company will soon commission China’s first offshore CCS project at its Enping 15-1 oilfield. The scheme involves capturing up to 300,000 tonnes per annum of CO2 and reinjecting it into a vault in the reservoir. The company aims to store up to 1.46 million tonnes of CO2 over the life of the field.
Wushi, being developed by CNOOC Zhanjiang along with local oil and gas developer Jiudin Energy and Zhanjiang Infrastructure Construction & Investment Group, is located 20 kilometres east of Wushi township in Guangdong province in water depths of between 14 and 28 metres.
The Wushi development comprises five oil assets — Wushi 17-2, Wushi 16-1, Wushi 16-1W, Wushi 23-5 and Wushi 16-9.
CNOOC has discovered almost 100 million cubic metres (about 628.98 million barrels) of oil reserves at the five fields.
The Wushi oil complex development is divided into three phases, with the first phase focusing on Wushi 17-2 involving 21.87 million cubic metres of oil reserves, while, in the second phase, CNOOC will develop fields led by Wushi 23-5.
In the first phase, CNOOC will drill 49 directional wells, with well depths designed to reach 3300 metres.
Production is expected to hit 1.5 million cubic metres per annum, expandable to 2.5 MMcm in the second phase.
The development of the second and third phases will call for construction of two wellhead platforms, one of which is an eight-leg fixed unit (WS16-1W WHPA) with 48 drilling slots. The second platform, WS23-5WHPA, will accommodate 30 drilling slots.
A subsea pipeline spanning 2.1 kilometres will be constructed between the two platforms. Meanwhile, CNOOC Ltd will build two export pipelines to link the fields and an onshore terminal in Wushi county.