Woodside Petroleum’s Pluto LNG Project will include an LNG production train at the Burrup LNG Park with forecast production of 4.3 MMt/a. The onshore LNG train will process gas from the offshore Pluto and Xena fields, which are estimated to hold a dry recoverable gas volume estimated at 4.6 Tcf of gas and 0.5 Tcf of contingent resources. First gas from the field is expected in late 2010 and first LNG in early 2011 – only six years after the discovery of gas in the Pluto and Xena fields.
The pipeline scope of work consisted of:
– Two 27 km, 20 inch diameter production flowlines transporting gas to a riser platform in 85 m water depth;
– A 180 km, 36 inch diameter export trunkline transporting gas from the platform to an LNG plant onshore Dampier;
– A 180 km, 6 inch diameter MEG line supplying the platform with MEG; and,
– A 27 km, 4 inch diameter MEG line supplying the MEG to the subsea system.
During the detailed design stage,for the pipeline, a team of 50 engineers from JP Kenny worked on the Pluto project. The role of the engineering support team was to manage design changes immediately prior to and during construction, focus site on the fabrication of design critical components, and assess the impacts of deviations from design, installation and construction procedures.
Allseas Construction Contractors began preparation for pipeline installation in January 2009, with the survey of the 20 inch diameter flowline routes and the installation of over 50 seabed transponders to enable the pipelines to be accurately installed within the tight tolerances dictated by the seabed topography and lateral buckling design.
An evaluation of a range of different LNG plant sites and corresponding pipeline routes resulted in Holden Point on the Burrup Peninsula to be selected as the preferred site to receive and process the natural gas.
“Whilst this pipeline route was attractive compared to the other options considered, the shore approach in Mermaid Sound to the Holden Point landfall location was very challenging,” Woodside’s Offshore Trunkline and Flowline E&C Delivery Manager Hosi Sabavala said.
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