The shallow water Bozhong 26-3 oil field expansion project commenced production in August 2021. Image courtesy of Offshore Oil Engineering Co., Ltd.
China National Offshore Oil Corporation (CNOOC) is the operator and developer of the Bozhong 26-3 oil field expansion project. Image courtesy of J. Stephen Conn.
The project is anticipated to hit a peak production capacity of 2,670 barrels of oil a day in 2021. Image courtesy of NOAA Photo Library.

The Bozhong 26-3 oil field expansion project located in Bohai Sea, China, produced first oil in August 2021.

Chinese state-owned oil company China National Offshore Oil Corporation (CNOOC) is the operator and holds 100% interest in the expansion project, which is expected to reach peak production capacity of approximately 2,670 barrels per day (bpd) of crude oil in 2021.

Location and field details

The Bozhong 26-3 oil field expansion project is located in the southern part of the Bohai Sea, China. It is a shallow water field with an average water depth of 21m.

The field lies within the Bozhong 26-3 oil field area, which is situated 118km from Longkou, Shandong province, China. The Bozhong 26-2 and Bozhong 25-1 South oil fields are also located in the area.

Geology and structure

The Bozhong 26-3 structure lies in the north-western depression of the Huanghekou Sag oil-bearing zone located in the south-eastern part of the Bohai Bay basin. The primary oil-bearing strata of the oil field lie in the lower part of the Minghuazhen Formation.

Bozhong 26-3 field expansion project details

The Bozhong 26-3 oil field expansion project included the installation of a new four-legged unmanned wellhead platform (BZ26-3WHPC) comprising nine well slots and a new three-legged power platform (BZ26-3PAPD).

The project also included the installation of a 4.4km-long wellstream export pipeline from BZ26-3WHPC to BZ26-3PAPD, and a 4.4km-long water injection subsea pipeline from BZ26-3PAPD to BZ26-3WHPC. A submarine power cable was also installed from BZ26-3PAPD to BZ26-3WHPC.

The BZ26-3PAPD power platform, weighing about 1,500t, is connected by a trestle bridge to the existing BZ26-3WHPA wellhead platform, which was upgraded as part of the expansion. The modifications carried out on the BZ26-3WHPA wellhead platform included upgrade of electrical and instrument rooms, and platform deck and pipelines expansion. The facilities on the power platform include a crude oil treatment system, a production water processing system, a water injection system, and a 4,200kW gas turbine generator set.

The expansion project includes the drilling of five production wells, two water injection wells, and one appraisal well.

Contracts awarded for the Bozhong 26-3 expansion project

Offshore Oil Engineering (COOEC), a subsidiary of CNOOC, was contracted to execute the installation of the new wellhead platform and power platform for the expansion project.

Hangzhou Hollysys Automation, a subsidiary of Hollysys Automation Technologies, was awarded a contract to provide process control systems for the project.

Bozhong 26-3 oil field development details

CNOOC drilled a total of 27 development wells in the Bozhong 26-3 oilfield including 15 production wells apart from four gas production wells, seven water injection wells, and one water source well. The daily oil production at the field is 780m3.

Bohai area development details

Bohai is the main crude oil producing area in CNOOC’s portfolio. The water depth in the area varies from 10m to 30m. The shallow water fields in Bohai primarily produce heavy oil.

CNOOC’s reserves in the Bohai area as of 31 December 2020 were 1,443.9 million barrels of oil equivalent (Mboe) accounting for 26.9% of its total reserves. The production from the area as of 31 December 2020 was 477,374 barrels of oil equivalent a day accounting for approximately 33.1% of the company’s total production.

New oil and gas discoveries made by CNOOC in the Bohai area in 2020 were Bozhong 8-4 South, Bozhong 13-2 deep formation, Bozhong 19-6 North, Caofeidian 28-1, and Kenli 9-2.

CNOOC also appraised 20 oil and gas bearing structures in the area during the same year, including Bozhong 13-2, Bozhong 21-2, Bozhong 26-3, Caofeidian 2-2, Caofeidian 6-2, Kenli 10-1 North, Kenli 6-1, and Luda 10-5/6.

The new developments that commenced production in 2020 and 2021 include Penglai 19-3 oilfield block 4 adjustment/Penglai 19-9 oilfield phase II, Qinhuangdao 33-1 South oilfield phase I, Bozhong 19-6 condensate gas field pilot development project, Luda 16-3/21-2 joint development project, Penglai 25-6 oilfield area 3 development project, Luda 29-1 oilfield, and Caofeidian 6-4 oilfield.