A subsea gas pipeline was needed for Woodside Energy two transport liquified petroleum gas and condensate from two gas fields: Geographe (55 kms south of Port Campbell), and Thylacine (70 kms).
The transfer of the gas took place of a 20-inch diameter pipeline that will transport the resource to an onshore processing plant.
The transition from subsea to onshore pipeline was a key challenge in the transportation of the gas, as the area is well known for its high-energy wave conditions that could potentially damage any above-ground pipe at the coast.
Another challenge was that most of the coastline suitable for the work is classified as either National Park or Coastal Reserve, meaning environmental impact needs to be miniscule. The area was, and is, a major tourist destination, which further required that it be maintained in its current state.
The pipeline construction concept, delivered by Atteris, originally considered traditional open cut and cover methods. Microtunnelling options were also assessed, but deemed unfeasible when compared with larger-scale horizontal directional drilling (HDD).
HDD methods saw the project delivered under budget and within the recommended schedule. The study found that there was no detrimental effect on the local environment, and no lasting negative impact on communities in the area.
As oil and gas operators explore increasingly challenging areas in the search for more resources, these challenges are transferred in turn to pipeline engineers to overcome.
The Otway Gas Project formed a benchmark for trenchless solutions as a method for overcoming difficulty.
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