ORIGIN Energy has launched plans to build a 33 kilometre pipeline to link two gas fields with its Otway Gas plant, north of Port Campbell, as it seeks to commercialise the fields.
The Halladale and Speculant fields are located roughly 5 kilometres offshore but are outside of the Otway gas project joint venture area, with both connecting to an onshore well site near Nirranda South, about 30 kilometres east of Warrnambool.
Origin plans to connect this well to the Otway gas plant to allow the gas to be processed prior to it being transferred into Origin’s Victorian gas distribution network.
To do this, Origin plans to build a 200 millimetre natural gas pipeline alongside a 50 millimetre mono-ethylene glycol (MEG) pipeline that will transport MEG in the opposite direction, to the offshore wells.
A 30 core fibre optic cable will also be installed between the two locations, all within a common trench within pipeline easement, with Origin planning to use an existing 24 kilometre pipeline easement.
Results from exploration drilling at the Halladale and Speculant fields showed gas production rates would be between 20 and 30 petajoules (PJ) per day averaged over 10 to 15 years, with a maximum early flow of about 65 PJ per day.
Origin had aimed to reuse the pipeline already in the easement, stretching from between the onshore Croft field well and the site of the former Heytesbury gas plant.
This strategy would have required it to build only a 1.6 kilometre line linking the wells to the Croft site and another 7 kilometre pipeline linking the Heytesbury and Otway gas plant sites.
However the company was forced to abandon the plan in light of the production forecast, with the higher estimated rate of gas production meaning that the higher capacity 200 millimetre pipeline was needed throughout.
Construction of the pipeline is set to start in the fourth quarter of this year, with a targeted date for the start of operations in the third quarter of 2016.