Perspective: New service requirements and technologies for pipelines emerging in this millennium

Oil is now extracted by emulsifying tar sands, gas can now come from low pressure seams in coal or trapped amongst near surface shale deposits, plus excessive evaporation of water in channels has given rise to a huge quantity increase in water pipelines as a variation to the traditional service regimes. Carbon is the other new player, and pipelines are set to become a critical transport link in the carbon capture and storage (CCS) playing field.

Resource diversity and pipelines

Pipelines in this category are being designed and built around the world. The USA has maintained its huge thirst for oil, and for many years the oil price did not justify the mining of the massive Alberta tar sands proven north of the 49th parallel. That changed markedly early in the decade when $US50/bbl was reached and then went on to almost treble. Field processing and diluents were added. The subsequent development of big and long pipelines to the midwest US saw a construction industry rationing their offerings due to the demand avalanche. The global financial crisis in 2008-09 has seen some pullback, however the current gradual oil price climb is bringing deferred projects back, and Canada in particular is poised to re-ignite boom times for heavy oil activities.

Low pressure gas is also making its mark on pipelines internationally. A great example is the remarkable expansion of coal seam gas (CSG) in Queensland, within reasonable distance of established consumers and coastal ports where, when liquefied at those locations, can offer LNG to the world. This onset over the last few years has changed the mix for pipelines and associated methodologies.

Low pressure gathering systems are now extensive, and plastics and fibreglass are joining steel as part of the contractor toolbox of capability. Each has its own welding and other speciality services to be deployed. On the other hand, large CSG volumes mean large diameter transmission pipelines, and after decades of building long skinny pipelines, contractors must now be in the “˜big inch’ league.
The drought in Australia, labelled “˜the worst ever’ prior to 2010, has seen water restrictions applied by governments to farmers and city dwellers alike. Traditionally water from the great inland rivers met the demand, but as the “˜big dry’ hit, new requirements evolved to ensure water reached its designated consumers rather than disappear by evaporation en-route. The solution by those in power has favoured pipelines over open channel irrigation systems, and a rash of projects has ensued, particularly up the east coast, with the pipeline industry adapting to many miles of buried plastic.
This water crisis has also seen the rise of multiple desalination projects with the net result being very large diameter (in the order of 2 m) steel pipes. This downstream delivery infrastructure brings new logistical and technical challenges for designers and contractors. The big rains of 2010 have temporarily tempered the outlook, but the new water pipeline regime is likely to remain a permanent feature in the landscape, or immediately beneath the surface thereof.

Carbon in them thar pipes

The world’s hot topic (somewhat cooled in Copenhagen) is manmade “˜bad’ emissions contributing to that target cap temperature increase of 2 degrees. Whether you’re a believer or sceptic, carbon is the physical issue, with governments and institutions already spending real money to study, evaluate, and where possible, create a demonstration project to capture carbon dioxide, transport it to a suitable location where it can then be safely sequested, presumably in some form of underground geological trap formation.

For us the key word here is transport, and to do this pipelines are the logical truckers. Pipelines, for this substance, are already established in North America and some other select locations based on the economical use for enhanced oil recovery (EOR), so some of the technical and safety issues are known.

Carbon dioxide transportation in pipes, strictly for safe disposal, is essentially the new frontier of expansion. In Australia, Federal Government initiatives and funding allocations have seen state sponsored programs emerge to compete for those funds directed to convince voters that the topic is serious and action is underway. Projects in this category include the ZeroGen and Wandoan (Bowen and Surat basins) offerings in Queensland, the CarbonNet (Latrobe Valley) proposal in Victoria, and the Collie Hub initiative in Western Australia. Each has a significant pipeline component, with key APIA members leading the charge in engineering the solutions – an activity essentially confined to the last two or three years only.

The engineering and solutions use oil and gas standards as their base line. AS2885 is enshrined under most licensing regimes as the appropriate “˜line in the sand’ to ensure integrity is the key criteria. The good news is that AS2885 is a risk-based code, and if the risks are more intense then the design will be required to reflect that status. Papers have been written on the adaptation of AS2885 for carbon dioxide service, and the general consensus seems to be that the ME38 Committee should appropriately consider an Addendum issue for carbon dioxide to complement the current 2007 version.
The main technical issue that emerges is to ensure the carbon dioxide is kept dry as water inclusion can give rise to potential corrosion from carbonic acid. Plus, appropriate metallurgical issues need to be addressed relative to pipe steel fracture toughness and heightened carbon dioxide failure mechanisms. Other pertinent design issues arise relative to the chemical critical pressure of carbon dioxide and the decision to maintain it as a gas (larger diameters required) or compress it at source through critical pressure, and design the pipe for the super-critical phase (which is essentially a liquid, hence smaller diameter pipelines would be required) and provide pumping as needed downstream to meet the throughput demands.

Finally, the engineering solutions are all safety driven. Carbon dioxide, although not toxic, is an asphyxiant, and communities will need comfort that such pipelines across their land are not an unreasonable hazard. Design, and in particular pipeline routeing (away from enclosed valleys), will need expertise commensurate with these risks and needs.
If the last 10 years have brought these pipeline changes, imagine where we will be in 2020 when/if “˜peak oil’ starts to bite.

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