Expanding Australia’s gas networks

Pipe lengths on the ROW near Wallan, Victoria.

Pipe lengths on the ROW near Wallan, Victoria.

In an effort to improve gas liquidity in Victoria and NSW, APA Group’s Northern Interconnect Expansion project will increase firm peak winter gas flow capacity from the Victorian Transmission System into the Moomba Sydney Pipeline System by 145 per cent, helping to further expand the operator’s east coast capacity.

The Victorian Northern Interconnect Expansion (VNIE) project is centred on the looping of sections of the existing 269 km 300NB Wollert to Wodonga Pipeline, and is one of APA’s key projects in securing its east coast gas network.

The VNIE Project is comprised of three separable portions and installation of two valve station facilities:

-Separable Portion 1: Construction of a 68.4 km pipeline loop from the Euroa Compressor Station Discharge to Glenrowan, including the installation of cross tie connections at Euroa and Glenrowan.

-Separable Portion 2: Construction of a 17.4 km pipeline loop from Wandong to Broadford, including a tie-in at Wandong to the first looping of the VNIE project and cross tie connection at Broadford.

-Separable Portion 3: Construction of a 49.8 km pipeline loop from Mangalore to Euroa Compressor Station Suction, including the installation of cross tie connections at Mangalore and Euroa Compressor Station Suction side.
Installation of the Glenrowan pressure regulator station and installation of a class break valve station facility at Euroa.

The pipeline looping and associated facilities have been designed, constructed and will be operated in accordance with the Australian standard for pipeline construction, AS 2885.

CONSTRUCTION
The expansion project involves the construction of looping sections of the existing 300 mm Wollert to Wodonga Pipeline, with a new 400 mm transmission pipeline within APA’s existing gas pipeline easement.

Engaged by APA to provide construction services, Nacap Australia’s mainline crews have been constructing the works at an astonishing rate of 2.5 km per day.

Nacap Project Manager James Povey said construction on the VNIE has set new records for the state.

“This is the first time in many years that a pipeline has been built in Victoria at 2.5 km/day production rates.”

Mr Povey also outlined the terrain on which the construction is taking place threw up its fair share of difficulties.

“The terrain and level of interruptions (property boundaries, roads and crossings) were a significant impost on the project,” said Mr Povey.

“Nacap presented a flexible pipeline construction operation capable of accounting for these challenges and ensuring production targets were met.”

In some cases, there were a number of narrow right-of-way (ROW) sections, due to the work being within seven metres of the Wollert to Wodonga pipeline, which necessitated the formation of a special section crew capable of working on reverse and narrow ROW.

The many roads and waterways intersected by the ROW meant that three special crossing crews were required to execute crossings in advance of the mainline activities, which allowed one of the three following tie-in crews to weld mainline lowered-in pipe.

As part of the scope of works, Nacap was also responsible for the mechanical installations at the start and end of each of the loops to connect into the existing Wollert to Wodonga pipeline.

There were also five locations that require end-of-line or mid-line facilities works installation.

The project was constructed in a combination of rural and domestic areas. Therefore, a key issue was housing the project workforce for the duration of the project.

Many local towns along the project alignment welcomed the diverse project workforce and it proved to be a welcome change from the intensive camp environments that Nacap workers been working in for the past three years, including remote camps constructing parts of the Australia Pacific LNG Project in 2012–14.

HDD WORKS
A number of major roadway, railway and waterway crossings presented problems that were addressed using major horizontal directional drilling (HDD), minor HDD and laser-guided pipe-jacking.

Nacap sub-contracted Pipeline Drillers Group to undertake the major HDD works, who worked effectively to deliver project milestones in an environmentally sensitive area, amongst well kept private properties.

Mobilising a Vermeer 330 in December 2014, Nacap and Pipeline Drillers installed four 406 mm gas pipelines of lengths between 210–560 m, before the end of April 2015.

New integrations between the companies’ safety and environment management systems, ensured an incident-free project completion.

Nacap also sub-contracted Victorian drilling contractor Pezzimenti Trenchless for laser-guided pipe-jacking, who, in January, commenced a month-long drilling operation on the project.

Working to a 28-day straight work cycle, Pezzimenti completed three pipe jacking bores, each with a diameter of 700 mm and crossing beneath rail lines.

Measuring 45 m, 60 m and 117 m in length, respectively, the bores crossed beneath the Benalla to Yarrawonga Railway, the North Eastern Railway and the Goulburn Valley Railway.

SAFETY
With 290 people working on the project during peak production, safety was one of Nacap’s top priorities.

Key issues around trench safety, lifting safety and project driving were encountered and managed through close supervision and systems specifically designed around accountability of stakeholder.

“A key tool to ensure ownership of safety is in the field based teams identifying risks involved in performing their tasks and the development of Safe Work Method statement that provides treatment to these tasks via the hierarchy of hazard control and As Low As Reasonably Possible (ALARP) principles,” said Mr Povey.

COMMUNITY ENGAGEMENT
Community engagement was crucial to the overall project’s success, with negotiations taking place in and around significant private properties. APA Group undertook comprehensive stakeholder liaison prior to Nacap’s mobilisation.

As the gas pipeline is a duplication of an existing gas pipeline, landowners were familiar with the requirement of the existing line, although many hadn’t experienced the original pipeline construction activities undertaken 40 years earlier.

Wildlife and livestock management were integrated into daily operations due to their close proximity, ensuring any potential occurrence was managed safely and with limited impact on fauna, with the initiatives well received by stakeholders and the local community.

CULTURAL HERITAGE AND ENVIRONMENTAL PROTECTION
Nacap also ensured that cultural heritage was a top priority on the project, with a number sites being protected.

“A feature of the landscape north of Mangalore are the large old growth native trees (River Red Gum, Yellow Gum, Grey Box), which provided scenic relief and native habitat to indigenous wildlife,” said Mr Povey.

“These trees were preserved where not directly impacted by the pipe trench line and enabled the retention of old growth corridor habitat links.”

Along the entire alignment of the project there was a requirement for cultural heritage clearance involving traditional owner representatives traversing the alignment to identify features or items of cultural significance and collecting them for further study and preservation.

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