The Chim Sao field is located in blocks 12W and 12E, which lie at a water depth of 377ft, 400km offshore Vietnam. Formerly known as Blackbird, the field was discovered in 2006. Premier Oil is the operator of the field with a 53.12% interest. The other partners are Santos 31.88% and PVEP 15%.

The Chim Sao field development plan was approved in 2008. The first phase of development involved two wellhead platforms to be tied back to FPSO Nexus 1 of Nexus Floating Production. Later, however, the FPSO lease arrangements were made with a joint venture of Ezra Holding, EOC, PetroVietnam and KSI Production in February 2010.

Production from the field began in October 2011. The field is expected to produce 25,000bopd and around 25mcft of gas per day.

Chim Sao FPSO vessel

Nexus 1 was developed by transforming Lewek Emas, a 168,000dwt suezmax oil tanker. The vessel has the capacity to process around 50,000bopd and 89mmsfc per day of gas. Its water injection capacity is 60,000bpd. The storage capacity of the vessel is 660,000 barrels of oil.

The conversion is being carried out at Keppel Shipyard and will be completed in 18 months. The FPSO is expected to be installed by the second quarter of 2011, with production expected to start in July 2011.

The conversion was carried out at Keppel Shipyard, and was completed in 18 months. The FPSO was towed to Chim Sao field in July 2011.

Chim Sao drilling

"The Chim Sao field is located in Blocks 12W and 12E, which lie at a water depth of around 377ft."

The drilling and logging of discovery well 12E-CS-1X, in block 12E, was carried out in November 2006. The drilling resulted in a large tilted fault block, 21km south-west of the successful wells in the Dua field, and the updip of a previous well, which had good oil shows.

The discovery well was drilled to a total depth of 4,058m. The drilling encountered four oil-carrying intervals in the main Middle Dua target.

The drilling and testing of the appraisal well was concluded in May 2008. Consequently, the coring of reservoir and wireline logging operations followed, and two reservoir zones were drill-stem tested.

The first zone test reported oil flow at the rate of 1,650bopd in addition to 1.4mmscfd on a 40/64in choke. The second zone test resulted at a rate of 2,680bopd with 2.1mmscfd on a 48/64in choke.

The well was suspended as a future production well and the rig WilBoss was transferred to the Chim Ung prospect. The development drilling over the well began in 2010.

WilBoss rig

The WilBoss rig is an independent leg cantilever jack-type rig. Owned by Awilco, the rig was built by Keppel Fels in a Singapore yard in 2007. It can drill up to 400ft underwater and has a total drilling capacity of 30,000ft.

FPSO supply contract

The contract for supplying the FPSO for the project was awarded to EOC’s wholly owned subsidiary, Emas Offshore Construction and Production (EOCP), in late 2009.

"The WilBoss rig is a cantilever jack-type rig."

In January 2010, PetroVietnam Transportation (PVTrans) and EOCP agreed to form a joint venture for providing operations and maintenance services for the FPSO for 12 years. Following this, in February 2010, EOCP agreed to form a joint venture with Ezra Holdings, Keppel and PVTrans to co-own the FPSO.

The engineering, procurement, construction and installation (EPCI) contract for the wellhead platform, infield flowlines and gas export pipelines was awarded to PetroVietnam Technical Services (PTSC) in 2008. The platform jacket was installed in late March 2010.

The contract for the installation of a wellhead platform at the field was awarded to Saipem in December 2009. The scope of work included detailed engineering for infield pipelines and the installation of subsea pipelines, umbilicals and PLEMs.

DPS Bristol was contracted for providing detailed design engineering services for CSU, water injection and flare knock-out drum modules of FPSO by EOCP in December 2009.

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