Stybarrow Oil Field, Australia

Discovered in February 2003, the Stybarrow oil field is located in licence block number WA-255-P(2) in the Exmouth sub-basin, approximately 65km from Exmouth, off the north-west Australian coast.

Stybarrow and the adjacent small oil rim of the Eskdale field, have recoverable reserves estimated to be in the range of 60 to 90 million barrels of oil. First production is expected during the first quarter of 2008. The estimated economic field life is ten years.

BHP Billiton operates the field with a 50% interest; the other 50% held by Woodside Energy Limited. Water depth is approximately 825m, making it Australia's deepest oil field development. Stybarrow's project costs are approximately $600m, which includes the cost of field development.

STYBARROW DRILLING

The Stybarrow field was discovered in February 2003, when the Stybarrow-1 well, drilled in the Macedon member sandstone reservoir, encountered a gross oil column of 23m with 18.6m of net pay. This was followed by further wells on Eskdale-1 (March 2003), Skiddaw-1 and Skiddaw-2 (May 2003) and Stybarrow-2 (June 2003).

BHP Billiton then carried out an appraisal programme, notably Stybarrow-3, 2km north-east of Stybarrow-1 where it encountered a gross oil column of 6.5m, and the sidetrack well Stybarrow-4 which intersected a 16m gross oil column. They also carried out two further exploration wells in a water depth of 830m; Eskdale-2 which encountered a gross oil column of 13m and a gross gas column of 24m and Knott-1.

Nine wells were to be drilled by the semi submersible rig Atwood Eagle – seven subsea wells for the production of hydrocarbons, one well for the production of hydrocarbons from the Eskdale field and a further well for the injection of excess gas in the Eskdale field. The drilling programme took around nine months

FPSO STYBARROW VENTURE MV16

The subsea production wells are tied back into a Floating Production Storage and Offloading (FPSO). Called the FPSO Stybarrow Venture MV16, the disconnectable, double-hulled unit is owned and operated by MODEC.

The hull was built in Korea and then sailed to the Jurong shipyard in Singapore, where the topsides were integrated in a six-month programme.

The FPSO has a storage capacity of 900,000 barrels, a total liquid process capacity of 100,000bpd, a crude production capacity of 80,000bpd, and gas production capacity of 45 million standard cubic feet per day. It has an internal disconnectable turret which was provided by SOFEC. This enables the FPSO to evacuate if a cyclone were to develop in the area.

As a marketable crude oil, Stybarrow will be sought after because of its blending characteristics, its low sulphur, low contaminants and moderate acid, making it a crude oil of choice for North Asian customers.

STYBARROW INSTALLATION PROGRAMME

The seabed at the well centres has been found to comprise very soft sand / silt and carbonate clays of 10m to 20m thickness. The subsea anchors and mooring system for the FPSO were laid using the Normand Mariner between December 2006 and January 2007 and the flowlines were then laid ready for the arrival of the production vessel.

Subsea 7 and Technip were awarded the subsea EPIC installation contract, valued at over $160m. This included the design, manufacture, transport, installation and pre-commissioning of approximately 48km of flexible risers, flowlines and jumpers fabricated at Technip's flexible manufacturing facilities in Le Trait, France.

The contract also included the transport, installation and pre-commissioning of around 16km of dynamic and static umbilicals and associated electrical and hydraulic flying leads as well as the installation of the FPSO spider buoy and mooring system complete with anchors.

The offshore programme started in early 2007 using Technip's construction vessel, the Deep Pioneer, assisted by the CSO Venturer. Two Heavy Lift Vessels (HLVs) were contracted to transport the flexible flowlines and other subsea equipment.

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