They were joined by two young researchers from the Energy Pipelines Co-operative Research Centre (CRC), Nicolas Coniglio (University of Adelaide) and Cheng Lu (University of Wollongong).
Following the Joint Technical Meeting (JTM), the group undertook a sponsored study tour of pipeline transportation companies in North America, in which 6,000 km would be travelled by trains, planes and automobiles, a total of five cities would be navigated, and seven North American gas companies and three research centres visited.
JTM in San Francisco
The JTM is a biennial event bringing together experts and researchers from across the world to present findings on current research programs being managed by the APIA Research and Standards Committee (RSC) through its partnership with the Energy Pipelines CRC, the Pipeline Research Council International and the European Pipeline Research Group.
The JTM provides the forum from which further research is determined by workshop and discussion. Eight key themes ran through the course of the meeting, including mechanical damage, stress corrosion cracking (SCC) sizing and assessment, pipeline integrity, and advanced design and materials. These themes represented the leading issues where a more advanced understanding of pipelines is most required.
For example, papers presented in the mechanical damage session considered research on pipeline external damage and how models for calculating pipeline residual stress could be improved. Other papers followed similar themes, considering how mechanistic models could be improved for predicting burst and fatigue strength for pipeline dents.
- During the course of meetings more than 30 technical papers were presented. The technical papers were very interesting, particularly those provided by members of the Australian research community, which included:
- Education of pipeline engineers;
- Organisational safety, design and specification of line pipe and line pipe steels for weldability; and,
- Effect of uncertainties in hydrostatic test fluid temperature measurements on the capability to detect leaks in pipelines.
Research presented on pipeline safety in landslide areas was also relevant to subsidence issues in Australia and, although in its infancy, research on CO2 pipelines gained most traction.
Apart from the papers, the group became aware of how much research is being undertaken each year to improve the industry.
The YPF group also found the researchers very enthusiastic, now believing that they are the ‘unsung heroes’ of Australia’s pipeline industry.
Touring North America
Following the JTM, the group undertook a two-week tour of some of the largest gas transmission and distribution companies in North America. The list of companies and cities visited include Pacific Gas & Electric (PG&E) San Francisco; Southern Gas California (SoCal Gas) Los Angeles; Panhandle Eastern Pipeline Co, Williams Gas Pipeline and Rosen (US), Houston; TransCanada, the Didsbury Research Centre and Stantec in Calgary; and, finally Enbridge Pipelines, C-FER Technologies and Canmet Energy Research and Development in Edmonton.
These companies are integral to the North American pipeline system and partly responsible for transporting almost 50 per cent of the world’s gas. The difference, therefore, between the Australian system and the US couldn’t be more obvious.
Many of the pipelines in the US and Canada are huge, ranging between 26 inch (DN650) and 56 inch (DN1400) in diameter. The US alone has pipelines and many large mainline compressor stations capable of transporting over 600 Bcm/d of gas. This is almost 24 times of what is transported daily in Australia.
Some of the companies trace their roots back to the early 1800s, when gas lamps were installed in Los Angeles. These companies have pioneered many of the design and construction techniques used today, and have made advances in strain-based design for areas affected by earthquakes, land subsidence, permafrost and swamps.
Advances have also been made in automated welding techniques, and pipeline design and construction methods including pipe spans, pipe bridges and horizontal directional drilling (HDD). Recent applications of pipeline monitoring technologies, such as LiDAR (Light Detection and Ranging) for detecting ground movements and assisting pipeline designs have also been adopted.
Although there are vast differences between the Australian and North American industries, many of the challenges that the industries face are similar. Rick Gailing from SoCal Gas explained that the key issues affecting pipelines in California are earthquakes, soils liquefaction and land subsidence. These issues are similar to those found in the design of pipelines in Papua New Guinea (PNG) and New Zealand. The YPF group found that there was a lot of commonality on other issues, including the design of pipeline road and rail crossings, resulting in some intriguing conversations on the preferred configuration of concrete slab design to protect pipelines at these crossings.
The group was also privileged to be given guided tours of the gas control centres by senior management, with presentations on the complexities of maintaining sophisticated transmissions and distribution systems. The group was also shown many of their facilities including compressor stations, gas storage sites and research laboratories.
During the group’s meeting with Panhandle Energy, the Project Director for its Phase VIII Expansion Project, met with the group to discuss the challenges faced by his teams. The Phase VIII project was a $2.48 billion pipeline expansion aimed at increasing capacity by almost 870 TJ/d.
This was achieved by the construction of some 777 km of new multi-diameter pipelines across Alabama, Mississippi and Florida and 600 km of pipeline looping with existing pipelines. It was discussed that a large part of the project’s success was a combination of good communication practices and implementation of advanced quality management systems.
For example, on a project of this size, there was a constant risk of having pipe spools installed that were not to specification. Therefore, an electronic pipe identification system was employed with GIS tagging and, if any non-compliant pipe was found, it was removed immediately from site. These and other project management tools were employed effectively resulting in a project completed on time and on budget in the Northern Hemisphere Spring 2011.
Knowledge gained from vintage pipelines
As well as learning about the successes, the group was also informed about the failures and, in particular, the ongoing challenges presented by an ageing North American pipeline network. A large part of conversation was about vintage pipelines.
Vintage is a term given to pipelines constructed prior to 1970. When US Federal and state safety regulations came into effect in 1970 they required all pipelines constructed from this date to be pressure tested. The pipelines constructed prior to 1970 were allowed to have maximum allowable operating pressure (MAOP) determined by reference to the highest actual operating pressure between the dates of 1 July 1965 and 30 June 1970.
These vintage pipelines are often unpiggable and susceptible to all sorts of corrosion issues, including SCC due to inferior coating systems used during construction, as well as risks associated with encroachment and third-party damage. It was a vintage pipeline that was the subject of the recent San Bruno pipeline incident.
It was also intriguing to witness the different cultures between the companies visited. Some organisations were managed into large multidisciplinary teams, which would include engineers, operators and marketing personnel while others would work in independent, large departmental teams with the focus on cultivating experts. However, it was observed that no matter how each company was organised, all shared a rich enthusiasm for their industry, much like the Australian industry does for its own.
The study group gained vast amounts of knowledge from visiting these companies and was very humbled by the time and effort taken in welcoming the group. Part of the expectation of this study tour was to “increase industry knowledge and gain a better understanding of leading-edge research and to gain international contacts in a number of key pipeline and gas engineering disciplines”.
This was certainly fulfilled and, during a final beer on the rooftop of a pub in Edmonton, the group all agreed that every participant’s eyes had been opened to the fascinating elements that make up the Australian pipeline industry.
Listed below are a few key challenges observed during the trip which relate, in part, to the pipeline industry in Australia.
The San Bruno pipeline incident
In September 2010, a 30 inch diameter (DN750) natural gas transmission pipeline owned and operated by PG&E ruptured in a residential area in the city of San Bruno, California.
The pipeline rupture and explosion resulted in the deaths of eight people, 51 injuries, and caused substantial property damage. Approximately 1.3 MMcm of natural gas was released and made a crater approximately 22 m long, 8 m wide and 12 m deep.
The pipeline explosion gained significant media attention and increased the public’s awareness of high-pressure gas pipelines with several public enquires undertaken.
The reasons for the rupture are still being investigated, however upon initial inspection it was determined that the ruptured pipe section consisted of six pup pieces welded together and connected to longer pipe spools at each end.
The fracture initiated in a longitudinal seam in one of the pup pieces. Neither the existence of the longitudinal seam nor the pups were known to PG&E prior to the incident. A metallurgy assessment by the National Transportation Safety Board (NTSB) reported that there were a number of weld imperfections on the welds of all pup pieces. These imperfections were primarily due to a lack of weld penetration along the longitudinal seam as well as a lack of fusion, porosity and misalignment around the girth welds.
The MAOP for the pipeline was also based on historical operating pressures, as allowed by the vintage clause, rather than by any recent pressure test data. Following the NTSB report, a recommendation was issued which required all operators to re-evaluate how Maximum Operating Pressure (MOP) and MAOP is determined and requested that operators have records which were traceable, verifiable and complete. For those with many vintage pipelines, this presented a very significant and costly challenge.
The study tour met with PG&E’s senior management approximately nine months after the incident. As the investigations are still ongoing there was no discussion as to the reasons of the disaster, other than what has been publicly released. However, they discussed in detail the steps being undertaken to verify pipeline integrity by the rollout of a program called ‘2020 Pipeline Programme for Enhancing Natural Gas Pipeline and Reliability.’
The group was also shown the 2020 project offices where large multidisciplinary teams were tasked with assessing and re-defining their networks. The 2020 approach largely focuses on modernising critical infrastructure by expanding the use of automated and manual shut-off valves, undertaking direct inspections, development of next generation inspection technologies and implementation of industry best practices.
The team was also tasked with prioritising and performing hydrostatic testing of previously untested pipelines in high-consequence areas and direct verification of MAOP. The level of this undertaking was impressive and it was explained that every day provides new and difficult challenges. However, due to the team’s enthusiasm for improving its systems, progress was being made.
Australia is perhaps fortunate that many of its pipelines are not as old as those in the US. However, as Peter Tuft points out in his online blog about pipelines, it is possible that some of our oldest lines contain features that may not be tolerated by today’s standards. It is therefore important that for these old pipelines, records are assured and verified and MOP and MAOP are not based on historic operational data alone.
Another issue that could trickle though the industry is the location, type and spacing of shut-off valves, particularly in residential areas. AS2885.1 provides recommendations on valve spacing, however, it remains at the discretion of the licensee to select the type of valve and its configuration through design and an isolation plan. However, with the issue currently being investigated in the US, the recommendations may perhaps be wider affecting.
Unpiggable pipelines
Much of the discussion during the study tour focused on unpiggable pipelines.
An unpiggable pipeline is a pipeline that doesn’t permit a pipeline tool to pass possibly due to irregularities in the pipe geometry, or where fittings and bends restrict tools, or where launchers and receivers are not installed. This means that in-line inspection (ILI), which is one of the most effective means for assessing the integrity of a pipeline, cannot be completed.
Unfortunately, there was no all- encompassing solution found. However, it was interesting to listen to the approach taken by some in managing both unpiggable and piggable pipelines. For example, TransCanada uses risk-based modelling tools to maximise the integrity and safety performance of their pipelines as well as providing a tool to identify which pipelines required most attention.
These models were fed large amounts of data such as the age and size of the pipeline as well as the type of material and coating used. Operational and historical data would also be included, together with details of the pipeline’s location and surrounding population density. Using sophisticated algorithms, the models would determine the potential consequence of failure and detail a list of prioritised lines which required investigation.
The results from the models would be evaluated by an asset integrity team, which in turn would develop work packages. These work packages would include direct inspection, de-rating or use of tethered pigs or a combination of these. The work packages would also be forwarded to the gas control centre so that the works could be scheduled into the system plan to minimise interruption.
This type of assessment is not new to pipeline integrity management. However, the group was intrigued by the sophistication of the models. These models would be expensive to develop in-house and it’s questionable whether there would be any economic benefit for asset owners in Australia to use these models, particularly if they only had a small handful of pipelines in their portfolios.
Perhaps for those pipelines which are unpiggable in Australia, a more simplistic risk-based modelling approach could be adopted, if not already in use.
Strain-based design
A number of presentations covered strain-based design. These design methods are used predominantly in offshore engineering. It is also used for pipelines with large thermal variances such as required on the Alaskan Pipeline Project in Canada, or for areas which exhibit large ground movements such as earthquake-affected regions in California.
Strain-based design is where special consideration is given to thermal, soil and pipe properties so that strain can be adequately managed. Historically, this has required designers to determine whether a particular load was ‘load-controlled’ or ‘displacement-controlled’.
In today’s application, it is recognised that a designer has also to consider the intermediary effects of load and displacement control particularly those related to pipeline buckling.
Newer models of strain-based design are also being implemented, such as that used on the Alaskan pipeline by TransCanada. The developed approach considers how strain demand is distributed along the pipeline in view of strain capacities. This approach is being termed reliability-based design, and it is proving to be an effective tool in pipelines designed particularly where strain-based design models have proved unsuccessful.
In addition to reliability-based design, new computer-modelling programs are being used called PIDPA and GEOPIPE. These programs aid in the determination of gas hydraulic simulation (with respect to temperature), geothermal analysis and pipeline structural analysis.
The US and Canada are looking at ways of providing improved guidance on both strain-based design and reliability-based design so that both tools can be standardised and more widely implemented.
Final remarks
The experience shared by the group was extraordinary and a wonderful opportunity to gain an insight into the research being undertaken each year to improve the Australian industry’s understanding of pipelines worldwide.
As discussed, the differences between the Australian and North American industries are large, however the issues faced by both are not. There is also a lot of respect for the Australian industry by the Americans and Canadians, who were very keen to hear about the challenges the Australian industry has faced and the solutions developed.
All that remains now is for the group to keep the ties created and contacts open with the newly-made North American friends, and I am looking forward to the next JTM in Sydney to do it all again.
On a personal note, I would like to thank APIA, the Australian Gas Industry Trust, as well as the JTM event organisers and all companies we visited for the opportunity to undertake such a unique educational experience: one that is certain to help develop my career and provide great memories that will stay with me for years to come.
