Beibu Gulf: WZ6-12 & WZ12-8

Asset overview - Beibu Gulf Development and Production Areas
Location Beibu Gulf, offshore China

Two development and production areas totalling 76.2km2: WZ 6-12 and WZ 12-8 West.

Operator CNOOC Limited (development and production)

Roc Oil (China) Company (exploration and appraisal)

JV partners and interests
Field Development & Production Exploration & Appraisal
CNOOC Limited 51.0% 0%
Roc Oil (China) Company 19.6% 40%
Horizon Oil (Beibu) Limited

26.95% 55%
Oil Australia Pty Ltd (Majuko)

2.45%                    5%

Beibu first oil commenced in March 2013.

The development incorporates two remote wellhead platforms and one joint processing platform, which are connected by bridge to the CNOOC WZ 12-1A platform complex and utilise existing water injection and oil and gas processing facilities.

Ten development wells were drilled from the WZ 6-12 platform and five development wells from the WZ 12-8 platform.

An appraisal well in the WZ12-10-2 was completed for production and tied into the existing WZ12-8W production system in late 2015.

Cumulative oil production reached lower tariff tier of 2.21 million m³ (13.9mmbo) on 10 January 2017.

There are two undeveloped oil accumulations in the retained development areas: WZ 12-8 East and WZ 12-3.  An overall development plan is currently under preparation for WZ12-8E.

First production Production commenced in 1Q13 with production reaching forecast rates.

Reservoirs range from Eocene-aged fluvial-lacustrine sandstones of the Luishagang Formation, to Miocene-aged Jiaowei shallow marine sandstones, and the Oligocene-aged Weizhou sandstones.

Oil quality varies from light to heavy quality, low to medium viscosity, with some waxy crude.

The Block is in an area of known oil fields. The nearest producing field is Wei 12-1 (production from Weizhou Formation), 1,800m from the original Block 22/12 boundary.  The Wei 12-1 field includes a well which yielded one of the highest oil flows encountered anywhere in China: 34,000 BOPD. 


In 2002, ROC farmed into offshore Block 22/12 with 25% interest, drilled a well and discovered the Wei 6-12 oil field.ROC acquired operatorship and increased its equity to 40%.

In 2004, ROC drilled an appraisal well on the Wei 12-8 East oil field which confirmed the presence of oil but indicated that the oil was viscous so commercial development would not be straightforward.

In 2006, the drilling of the Wei 6-12S-1 exploration well made a significant oil discovery which was appraised by four wells.

Following the formal end to the exploration period for Block 22/12 on 30 September 2008, the Wei 6-12, Wei 6-12S and Wei 12-8 oil fields were declared development areas.

In 2Q10 CNOOC elected to participate for its full 51% share in the development, reducing ROC's share to 19.6%.

The Overall Development Plan (ODP) was completed in 2010 and following final CNOOC approval in January 2011 the joint venture proceeded to its Final Investment Decision in February 2011.

CNOOC assumed operatorship of the project in 2Q11 and a CNOOC operating subsidiary company (Weizhou Operating Company) was established.

The Environmental Impact Assessment (EIA) for the project was approved by the relevant Chinese Government Authority in February 2012, allowing development activity to commence.The project was sanctioned by the National Development and Reform Commission (NDRC) in 4Q12.

In 2013 the Beibu Gulf development project completed, with a fifteen well drilling programme completed safely and within budget.

Drilling in 2014 secured undeveloped areas and allowed boundary expansion. A successful discovery in the Wei 12-8 Mid area (WZ12-10-2) was integrated into the Beibu Project. An appraisal well was completed for production and tied into the WZ12-8W production system in late 2015.

Production performance from WZ 6-12 and WZ 12-8 remains in line with expectations.