Yacheng 13-1

Location and Geology

• The Yacheng 13-1 Gas Field is situated in the Qiongdongnan Basin of the South China Sea, approximately 90 km south of Hainan Island, China.
• The field is in shallow water, with a depth of about 293 feet (90 meters).
• The primary reservoir consists of Middle/Late Oligocene Lingshui-3 Member sandstones, developed during a major marine transgression. This geological setting created substantial accommodation space, resulting in thick reservoir sandstones with excellent reservoir quality.

Operator and Ownership

• The field is operated by China National Offshore Oil Corporation (CNOOC).
• Initially, the project was developed by ARCO China Inc. with partners CNOOC and Kuwait Foreign Petroleum Exploration Company (KUFPEC). In 2004, BP handed over the operatorship to CNOOC, and in 2013, BP sold its stake to KUFPEC.

Discovery and Production

• The Yacheng 13-1 Gas Field was discovered in 1983.
• Production began in 1996.
• The field has estimated reserves of more than 3 trillion cubic feet of gas, making it the largest offshore natural gas producing field in China.

Infrastructure and Development

• The initial field development involved two offshore platforms: a 15-slot wellhead platform and a production/processing platform. An additional accommodation platform was installed in 2004.
• The gas is transported through a 480-mile (approximately 770 km) subsea pipeline, which is the second longest subsea pipeline in the world, to supply gas to Hong Kong. A separate 14-inch pipeline supplies natural gas and condensate to local industries on Hainan Island.

Production and Reserves

• The field has recovered 98.51% of its total recoverable reserves as of the last available data. Peak production occurred in 2002, and production is expected to continue until the field reaches its economic limit in 2027.
• The cumulative gas production from the field was approximately 40 billion cubic meters (40000 million m³) as of 2019.

Sales Contracts

• The primary market for the gas is Hong Kong, where it is used for power generation. Additional gas and condensate are supplied to Hainan Island for local industries.

Environmental and Technical Considerations

• The development of the field involved extensive environmental data collection due to the lack of previous oil industry infrastructure in the area. The region is subject to typhoons and severe monsoon-driven winter weather, which posed significant challenges during the construction and operation phases.

Contractors and Partners

• Key contractors include Hyundai Heavy Industries (HHI) for the construction of the wellhead platform, and Saipem for the installation of the gas pipeline and other infrastructure.

In summary, the Yacheng 13-1 Gas Field is a major offshore gas project in China, operated by CNOOC, with significant reserves and a complex infrastructure to support its production and transportation to key markets in Hong Kong and Hainan Island.