The Penglai oil fields are a group of offshore oil fields operated by the China National Offshore Oil Corporation (CNOOC) in the Bohai Bay in northeast China.

Situated in the Block 11/05 in the Bohai Bay, the Penglai oil fields including the 19-3, 19-9, and the 25-6 fields are being developed in three phases. China’s state-owned CNOOC holds a 51% interest in the Penglai fields, while the remaining 49% stake is held by ConocoPhillips.

ConocoPhillips entered into an agreement with CNOOC to explore Block 11/05 in December 1994 and discovered the Penglai 19-3 oil field in 1999. The initial production in phase one was started in December 2002, while the phase two development became fully operational in 2009.

Although ConocoPhillips was the operator of the Penglai fields since the beginning, it transferred the operatorship to CNOOC in July 2014. The Penglai 19-3/19-9 phase three project was sanctioned in 2015, while the first oil was produced in 2018 with the full production capacity expected to be achieved in 2020.

Penglai oil fields location

The Penglai oilfields are located in 30m-deep waters in Block 11/05 in Bohai Bay, off the coast of northeast China, approximately 235km southeast of Tanggu, Tianjin, China. The Block 11/05  is spread over approximately 2.3 million acres.

Penglai fields development phases

The phase one development was an early oil production project that involved a wellhead platform and the Ming Zhu floating production, storage, and offloading (FPSO) vessel. The design production capacity of this phase was up to 40,000 barrels per day (bpd) and it came on stream in December 2002.

The phase two development that became fully operational in 2009 involved the development of all three fields including Penglai 19-3, 19-9, and 25-6 with six drilling and production platforms and the Peng Bo FPSO vessel. The first wellhead platform to start production in Phase 2 was Platform C in June 2007.

The Peng Bo FPSO, also called as Hai Yang Shi You 117, went on stream in May 2009. The hull’s dimensions are 323m-long, 63m-wide, and 32.5m-deep. The design processing capacity of Peng Bo is 190,000bpd while the storage capacity is two million barrels.

The Penglai 19-9 oil field witnessed further development with the addition of the wellhead platform J (WHP-J) which started production in 2016. As of 31 December 2019, 57 out of the planned 62 wells were in operation at the field.

The Penglai 19-3/19-9 phase three project, sanctioned in 2015,  comprises three wellhead platforms namely, WHP-V, WHP-G and WHP-K, and a central processing platform.

The oil production from platforms WHP-V and WHP-G were started in 2018 with the WHP-K slated to come on stream in 2020.

Recent developments in the Penglai fields

The Penglai 19-9 comprehensive adjustment project with a new wellhead platform and two wells started production in January 2017.

The Penglai 19-3 oilfield 1/3/8/9 comprehensive adjustment project with two production wells went on stream in September 2018. The major production facilities of this project include two wellhead platforms and a central processing platform. The peak production capacity of this project is expected to reach 58,700bpd in 2020.

The Penglai 19-3 oilfield area 4 adjustment/Penglai 19-9 oilfield phase II project commenced production in May 2020. The project involves a new wellhead platform which is planned to be connected to 30 production wells and 16 water injection wells. The oil output of this project is expected to reach up to 15,681bpd in 2022.

The Penglai 25-6 Phase 4A project comprising a new wellhead platform was sanctioned in December 2018 with the first oil expected in 2021.

Contractors involved

Fluor provided conceptual engineering, front-end engineering and design (FEED), as well as detailed engineering services for phases one and two of the Penglai fields development. The scope of the contract included design, procurement, and construction services for the Peng Bo FPSO, six wellhead platforms, and associated pipelines for the project.

Shanghai Waigaoqiao Shipbuilding Corporation, a subsidiary of China State Shipbuilding Corporation (CSSC), received a contract worth more than £104m ($200m) for the hull construction of the Peng Bo FPSO vessel in March 2005.

Halliburton’s Sperry Drilling was awarded a two-year contract worth £25.5m ($40m) for directional-drilling and logging-while-drilling services for the Penglai fields in February 2010.

Offshore Oil Engineering Corporation, a subsidiary of CNOOC, hoisted the east and west modules of the WHP-K wellhead platform for the Penglai 19-3 Oilfield Area 4 Adjustment / Penglai 19-9 Oilfield Phase II development project in February 2020.

Oil spill in Penglai 19-3 field

The Penglai 19-3 oil field witnessed oil spill incidents at platforms B and C in Bohai Bay in June 2011. ConocoPhillips was the field operator during the oil spill.

The production from the entire Penglai 19-3 field was suspended following an order from the Chinese authorities in September 2011.

The seepage incidents resulted in the release of approximately 700 barrels of oil and 2,600 barrels of mineral oil-based drilling mud into the Bohai Bay.

The operator received approval from China's State Oceanic Administration to resume operations in February 2013.