Jemena invested more than $100 million in the expansion of its Queensland Gas Pipeline (QGP) to meet projected gas demand in the area required a doubling of the pipeline capacity.
Originally constructed during 1989 to 1991, the 627 km QGP and Rockhampton branch line transports gas received at the Wallumbilla Gas Hub from the Surat and Cooper basins, the Denison Trough and the southern Bowen Basin to large industrial customers.
The large industrial customers include Queensland Alumina, Rio Tinto, Orica, Boyne Smelter and Queensland Magnesia. Gas is also supplied to households and businesses via the distribution networks within Gladstone, Rockhampton and Wide Bay.
Complex flow and capacity modelling, together with budget build prices, revealed that 113 km of looping between Oombabeer Scraper Station and Callide – along with two midline compressors at Rolleston and Banana – would achieve the required capacity increase.
The minimum and maximum supply pressures were identified at the withdrawal and injection points on the QGP to ensure no adverse affect would be imposed by the new operating conditions.
Engaging the industry
Jemena engaged AJ Lucas for the looping component of the project under an early contractor involvement (ECI) strategy. This enabled AJ Lucas to understand the risks and challenges associated with the project, including the general terrain; road, rail, river, creek crossings; fencing; logistics management; traffic management and geotechnical conditions.
The two companies worked together to finalise the design prior to construction commencing. Project risks were mitigated and the construction build price was refined to reflect the scope, which meant that cost overruns were kept to a minimum and the project was successfully completed on budget.
A thorough estimation process and geotechnical field investigation were undertaken to assess the potential risk of encountering rock along the route during the ECI phase, which resulted in a significant project saving.
Enerflex Process installed the compressor stations under a cost plus contract with agreed target price, and with an associated pain/gain mechanism for performance to budget. Key performance indicators ensured the correct incentives were provided in the contract around safety, environment and quality.
Project timeline
The front-end engineering and design (FEED) for both the pipeline and compressor stations was completed in August 2008 followed by the ordering of long lead items. The overall project was required to be completed by 1 April 2010.
The detailed design for the compressors was completed between September 2008 and March 2009. The construction was launched in parallel with Rolleston civil works starting in October 2008.
Construction for both facilities ran from October 2008 and was completed in September 2009. Each site was then commissioned over a two-month period, with practical completion achieved in December 2009.
The pipeline looping project camp, site offices, plant and equipment were mobilised by the end of May 2009.
The installation of temporary gates and fences; topsoil stripping and stockpiling; pipe delivery along the easement and pipe bending started in early June 2009.
During July and August, creeks, roads and rail crossings were underway, and the mainline work of trenching, welding, non-destructive testing, coating, lowering, backfilling, pressure testing and reinstatement followed in sequence through to completion in November 2009.
The pipeline scraper stations were completed in December 2009, with the pipeline commissioned at the start of 2010.
At the peak of pipeline construction, there were 310 people working directly on the project. Most of those were spread over a moving 20 km section of the worksite with a mainline pipe laying progress of approximately 2.3 km per day.
For the compressor stations up to 140 people worked on the construction and tie-ins.
Installing unique pipe
The looping portion of the expansion consisted of 113 km of DN 400 API 5LX70 PSL2 pipe externally coated with 700μm dual-layer fusion bonded epoxy and 50μm internal. The nominal wall thickness of the pipeline was between 5.4 mm and 7.2 mm.
Jemena Major Projects Group Looping Project Manager Nathan Biggins said “This project has presented a number of challenges due to the unique pipe that is being used. The pipeline is the highest diameter on wall thickness ratio pipeline to be built in Australia to the AS 2885.1 code.”
Designed to the new standard, AS2885.1-2007: Pipelines – Gas and liquid petroleum – design and construction, a thinner wall thickness of 5.4 mm for a 406.4 mm diameter was allowed, which resulted in a significant cost saving to the project by reducing the amount of steel required.
“The allowable wall thickness tolerance is only half a millimetre. As a result there is a requirement for much tighter controls at all stages of the project from the initial rolling and seam welding at the steel mill in Port Kembla, to when the pipe is loaded for transport, lowered into the ground and then hydrostatically tested,” said Mr Biggins.
For example, pipe bending processes typically allow 1.5 degrees per pull, which initially resulted in ripples forming in the bent pipe. The qualified bend procedure limited each pull to 0.7 of a degree.
While the pipe complies with the required standards, the pipe end ovality can vary. The acceptance criteria for high/low tolerance proved a challenge to manage during tie-in welding. In the tie-in weld instances it required particular skill and attention to align and clamp the pipes for welding.
During the hydrostatic testing process it was also necessary to maintain tighter control and monitoring of the pipe’s circumferential expansion.
Working with live pipelines
A 10 inch hot tap was cut into a 12 inch mainline and a full encirclement hot tap sleeve was installed at the eastern end of the looping at Callide.
One of the major challenges of the hot tap was to source a suitable test pipe for the weld procedure qualification. After an Australia-wide search for a suitable pipe, OneSteel’s Port Kembla plant was able to provide.
The remaining tie-ins to the existing DN300 mainline were cold-cut into existing tees located within the scraper station facilities.
In addition, working within the confines of an existing 25 m wide easement, with less than 10 m clearance from the existing fully-operational QGP transmission gas pipeline, was another challenge overcome by thorough safety planning and care.
To ensure that heavy plant and equipment was kept clear and the location was visible, stripped topsoil was pushed into a protective stockpile providing a perfect visual and physical barrier over the top of the existing pipeline.
Compressor station construction
The compressor stations each consist of a Solar Turbines Taurus 60 turbine driving a C334EH compressor.
The new compressor facilities needed to be integrated into an existing, aged asset with redundant technologies. This posed challenges for integration of station communications and protection systems.
In addition, the soil conditions at Rolleston presented a very real challenge. Locally known as “˜black soil’, the ground can be unstable, boggy and consolidates frequently. To ensure that the foundations are capable of supporting the compressor load without subsidence, Jemena used deep screw piers that extend down to the bedrock.
Safety first
One of the project’s major achievements was recording zero lost-time injuries (LTIs).
“We want everyone who works on a Jemena project to go home safe and sound at the end of the working day,” said Compressor Station Project Manager Jonathan Spink.
“Safety is supported at the highest levels in Jemena – from the Board and Chief Executive Officer downwards. We have a slogan “˜Zero Harm – Safety First’ to adhere to, and this includes any contractor or sub-contractor that works on our projects.”
The zero LTI result was supported through the presence of onsite management with a strong safety and quality culture. This included daily and weekly safety walks with the contractors.
No one was permitted onto the worksite without first undergoing a full induction that provided specific information about road, track and easement conditions, and any hazards that might be encountered in and around the heavy equipment and the excavation. In particular, the induction covered the limitations of working within a construction easement containing an existing operating gas transmission line.
To ensure safety while travelling, vehicles were fitted with GPS tracking devices to ensure that drivers and operators adhered to both regulatory and designated easement speed limits and also to ensure vehicles did not stray from the defined worksite easement.
A strict drug and alcohol policy was also in place for everyone onsite, which included random spot checks.
A 40-bed camp was erected onsite at the Rolleston compressor site, located more than an hour from the township, to improve safety by eliminating excessive travel and fatigue.
Caring for the environment
The pipeline was constructed in the existing pipeline easement. Even though the easement was considered to be already disturbed, Jemena engaged Cultural Heritage Monitors to monitor a significant section of the pipeline route to ensure any additional disturbance was minimised. Jemena negotiated and signed a Cultural Heritage Agreement with the Wadja Family Aboriginal Corporation and East Comet/West Dawson Traditional Owners Group for land culture and community development.
An essential part of the induction and training for all project staff and contractors was to ensure the protection of the environment, stock and crops.
Two bottle trees, remnants of an approximately 400 year old rainforest, were in the easement close to the pipeline, as was a significant eucalypt scar tree. These were identified early in the environmental audit and controls were put in place to ensure their protection during construction. Another bottle tree was identified at the Banana Compressor Station, resulting in a redesign of the fence line to avoid disturbance.
Special attention was given to strict procedures to prevent the spreading of noxious weeds, particularly the Class 2 declared weed Parthenium Hysterophorus. Six wash-down facilities were set up at strategic points in addition to a fully automated wash-down bay established for the project in the township of Moura.
Landowner contact was via a Stakeholder Manager who provided details of the proposed works and responded to any specific needs or concerns of landowners.
“Our objective was to construct our expansion works with the minimum of disturbance to landowners. We understand that we cannot avoid disturbance, but through discussions with each landowner we can ascertain their individual needs, record these in a construction line list for our contractor and then manage this process with the landowners,” said Jemena Stakeholder and Regulatory Compliance Manager Barry Milliken.
Conclusion
Jemena Managing Director Paul Adams said that the company has played an important role in supporting development in Gladstone and Rockhampton by ensuring gas supply is available for industry through the QGP.
“The pipeline industry will play a vital role supporting the growing demand for gas across Australia. At Jemena, we have extensive experience in pipeline development from the recently completed Colongra project, to the Sydney Primary Loop, and now the expansion of the QGP. I’m proud of the role Jemena plays in delivering these projects,” said Mr Adams.
Jemena will now move on to complete construction of a Jemena-owned meter station and a Rio Tinto-owned off-take station from the QGP, as part of Rio Tinto Alcan’s Yarwun Alumina Refinery expansion, located near Gladstone. The $1.93 billion expansion of this refinery will more than double the annual alumina production of the existing operation.
“This project is the key part of the jigsaw that includes Jemena’s QGP expansion and two compressor stations. The project will supply seven times the gas the refinery currently takes,” said Mark Rathbone, Jemena Major Projects Project Manager. “Our challenge is to complete our project safely, on-time, on budget and to the satisfaction of our client, Rio Tinto.”
In addition, Jemena has been appointed by Multinet Gas to deliver the Lilydale Pipeline Project, consisting of 10 km of 300 mm transmission pipeline from APA Group’s Yarra Glen City Gate to Multinet’s Lilydale City Gate, in Victoria. The project is to meet the growth in demand in the region to ensure reliability of gas supply during high demand winter periods.
QGP Expansion contractors
AJ Lucas (pipeline construction)
Enerflex Process (compressor and scraper station design and construction)
Australian Portable Camps (provision of temporary camp accommodation)
Quality Process Services (welding, hot tap welding qualification, site fabrication)
GHD (environmental audit)
OSD Pipelines (pipeline design)
Coffey Partners (geotechnical investigations)
Brian Martin & Associates (cathodic protection and coating design)
Geoff Cope (coating design)
Bureau Veritas (water testing, non-destructive testing)
Pearl Street and Stork Cooperheat Australia (non-destructive testing)
SAVCOR ART (cathodic protection system testing and commissioning, DCVG testing)
CCE [Corrosion Control Engineering] (supply monolithic insulation joints)
OneSteel and Bredero Shaw Australia (pipe and coating supply)
Powers Agribusiness (agronomy services – compensation calculations)
Unidel (environmental mapping, construction environment management plan)
Freehills & Blake Dawson (legal)