The 135.3 km Westernport – Altona– Geelong (WAG) Pipeline transports liquids from the Western Port terminal, situated in Outlook Avenue, Hastings, to refineries in Altona and Geelong.

Crude oil and gas is supplied to the WAG Pipeline from BHP and Esso’s Bass Strait and Gippsland Basin permits. Once brought ashore by pipeline to Esso’s treatment and separation plant at Longford, stabilised crude oil is transferred to the Western Port harbour for shipping and pipeline distribution via the WAG Pipeline.

The crude is conveyed 82.5 km via a 600 mm diameter section of pipeline to the Altona Metering Terminal on Kororoit Creek Road, Williamstown North, where part of the crude is delivered to the Mobil Altona Refinery. The balance of the crude is carried on via a 52.8 km, 400 mm diameter pipeline to the Geelong Metering Terminal situated in Shell Parade, Corio, where it is delivered to the Shell Geelong Refinery.

The pipeline was fully constructed and commissioned by the end of 1972, and is still operating efficiently after 38 years of continual service.

Former WAG Pipeline Manager Colin Symonds managed the pipeline for 20years. Here, he explains the challenges to pipeline management posed by the pipeline route, and the maintenance program employed on the pipeline.

Challenges of the pipeline route

Starting in Hastings on Western Port, the WAG Pipeline runs through the Melbourne suburbs of Moorabbin and Brighton, closely following Port Phillip Bay through Elwood, St Kilda and South Melbourne before continuing on to the Altona Refinery and Geelong.

The nature of the pipeline route through built-up areas means that stakeholders not only include Shell and Mobil as owners, BHP-Billiton and ExxonMobil as crude suppliers, councils and regulators – but also a large number of private and commercial property owners, and those based in industrial areas.

The pipeline passes through 764 non-company-owned land parcels of which 387 are road reserve, 55 are public reserve, 14 are rail reserve, 51 are Crown land and 253 are private land.

“About a third of WAG Pipeline’s time would be spent on stakeholder liaison,” says Mr Symonds.

“It is not only that proper inspection and maintenance regimes are required to be implemented and communicated to potentially affected landowners and other interest groups in the immediate vicinity of the pipeline. You also have to make sure you are across any advancing development (or encroachment) that may affect the asset in some way.

“When a new subdivision development is proposed, WAG works heavily with the developer in the early stages of their project to get the land use around the pipeline as either road or public reserve rather than to end in people's back or front yards. Most times we’re able to achieve this.”

Mr Symonds notes the importance of the APIA Pipeline Corridor Committee’s current work in championing the referral status of pipeline operators. Through the authorities, this status will make sure that any development proposed within an agreed distance of a pipeline must involve the pipeline operator in an advisory role, from first consultation through to project implementation.

“The further back up the planning route we can get, the more impact we can have in terms of making sure that the best outcome is achieved to avoid inappropriate co-location of pipelines and land usage,” says Mr Symonds.

Associated facilities

The Westernport Pump Station provides the only pressure boosting facilities on the pipeline. Three 1,440 horse power diesel engines driving multi-stage centrifugal pumps through speed increaser gears constitute the major equipment items.

The station is operated by one Pump Station Controller during each work shift. The Pump Station Controller is based in the control room building adjacent to the pumping equipment. Computerised supervisory instrumentation allows the operation and monitoring of all important functions at the pump station and the metering terminals at Altona and Geelong. Automatic alarm and shutdown systems protect the equipment from serious faults that might occur.

The main function of the Altona Metering Terminal is to control and meter the delivery of crude to the Mobil refinery, whereas the Geelong Metering Terminal controls and meters the delivery of crude to the Shell refinery. Both terminals generally operate in an unmanned state under the control of the Westernport Pump Station controllers. The pipeline inspectors and the Instrument Electrical Technician use the terminals as a base, performing various operational and maintenance tasks.

The maintenance program

Mr Symonds explains that WAG Pipeline Pty Ltd commenced using an intelligent pigging program in 1978 and has since maintained this at a 4–5 year frequency.

“The majority of corrosion found in the early pigging runs was attended to by the late 1990s. Since then, anomaly inspections are of light corrosion with most found to be inactive,” he says.

He says that this early corrosion was mainly due to a combination of poor field joint coating and poor backfill. “A lot of rock was included in the pipeline backfill, and this damaged the pipeline coating in some areas.”

Today, Mr Symonds says that a full pipeline coating defect survey is conducted every three years. From this, repair programs are undertaken, taking into account any identified coating defect severity and length, as well as cathodic protection levels and identified metal loss anomalies in the immediate area of the defect.

“Cathodic protection on the pipeline is regularly adjusted, particularly because of the potential effects of stray current from train and tram traction systems.”

Case in point: repair sleeve installation

A repair sleeve was recently installed on a section of the WAG Pipeline within the median strip of busy South Road, Moorabbin.

“This anomaly was identified by intelligent pigging as a lack of penetration of a girth weld,” says Mr Symonds.

The anomaly was located at a section of pipeline buried under a sewer main at a depth of approximately 5 m. The depth of the pipeline, in conjunction with the tight work area and with soil conditions being too unstable, precluded the use of the usual trenching and shoring.

“An elaborate system of sheet piling and bracing was required to access the pipeline,” says Mr Symonds.

The anomaly was found to be incomplete welding rather than a lack of fusion. Despite the many years of operation, there were no signs of fatigue cracking exposed by non-destructive testing. How to amend this anomaly was the challenge now being faced. All possible repair techniques were investigated. Due to misalignment of the pipe and differing circumference of adjoining pipe spools, it was determined that the only suitable method of repair was to employ a Plidco Split Plus sleeve. This decision was ratified by the Shell US technical specialists before commencing the repair. The rubber seal system of this sleeve allowed to be positioned over the inconsistencies of the pipes, bolted in place, and then fully seam-welded to form a permanent repair and to reinforce the incomplete girth weld.

A proactive approach

Mr Symonds says that “being proactive” is key to the successful integrity management of a pipeline.

He says that by doing this, the WAG Pipeline team has halved the maintenance requirements needed for the pipeline today compared to that of the early 1990s.

“Implementing a detailed inspection regime, and acting on those results, plus pushing the cathodic protection system up where it needs to be, has allowed us to get ahead of a tide of corrosion and mitigate it to a manageable amount.

“It comes back to the business being very focused on the intended life of the pipeline. And if there is no end time of the pipeline then you’re really forced into maintaining the pipeline for good. That’s basically the approach that I’ve proposed and that the WAG Board was adopted,” he says.