As Australia moves towards a cleaner energy future, more CO2 pipelines for carbon sequestration will be required. The Australian Pipeliner spoke with Pipe Tek Chief Operating Officer Taddam Farrant about the company’s successful pipeline and facility testing for contractor MPC Kinetic on Santos’ Moomba Carbon Capture and Storage Project and overcoming the challenges of working in the remote Cooper Basin.
Santos’ Moomba Carbon Capture and Storage (CCS) Project will deliver a large-scale CCS hub centred around the Moomba Gas Plant, targeting capture of up to 1.7 million metric tonnes (MMt)/a of CO2 for injection into depleted gas reservoirs in South Australia’s Cooper Basin. The monumental project is an important component of Santos’ industry-leading emission reduction target of net-zero by 2040.
The project includes a 53km, 10-inch diameter carbon steel pipeline to transport compressed, dehydrated CO2 from the Moomba CCS facility east to injection wells at depleted reservoirs in the Marabooka and Strzelecki fields. The heavy and standard wall pipeline is designed to transport the dense-phase CO2 at pressures between 10-15MPa.
MPC Kinetic (MPK) was contracted to construct the pipeline, who then engaged Pipe Tek to test the pipeline and five aboveground facilities before commissioning.
Why is this project so interesting?
Although the process of injecting into depleted reservoirs has been used for many years, CCS is a relatively new technology that has the potential to help Australia achieve a decarbonised energy future, with pipelines playing an important part in transporting the CO2 emissions.
Once completed, the Moomba CCS Project Pipeline will be the longest CO2 transmission pipeline in Australia, and its successful development will likely see more gas companies plan to sequester their emissions in Australia’s remote depleted reservoirs.
CO2 pipelines have some unique design and operational requirements:
Maintaining a supercritical flow of CO2 through the pipeline: Pure CO2 reaches supercritical form when in an environment with pressures above 7400kPag and temperature above 31C.
Dehydration: The CO2 needs to be dehydrated before entering the pipeline to avoid the formation of free water which could lead to pipeline corrosion or the formation of CO2 hydrates across throttling valves at pipeline de-pressuring vents and the injection wells.
MPK included rigorous testing requirements for both of the above elements as part of the Pipe Tek’s pipeline and above-ground facility testing brief.
The testing process
Pipe Tek’s Chief Operating Officer Taddam Farrant managed the pipeline and above-ground facilities testing.
Before testing could occur, a rigorous pre-cleaning process was required. Several cleaning runs were performed with an Enduro pig train to ensure the pipeline internal surfaces were burnished and substantially free of residual dust.
“We chose to use an Enduro bidirectional pig train and pig links. It included cups, brushes, gauge plates and magnets with bypass sealing discs to allow for optimal cleaning and reduce ferrous material left behind from the construction process,” Farrant said.
“We’ve been working with Enduro as part of an exclusive partnership deal since 2019 – we choose their tools because we believe they perform above their competitors and provide more efficient and reliable data to our clients.”
The pig train and a series of magnets were run through the pipeline until visual inspection showed the internal surfaces to be clean, bright and free from particulate rust and scale, and air exiting the pipeline ahead of the pig was clear and practically free of dust.
The pipeline was then filled using a bidirectional pig with high-wear discs before being strength and leak tested to 21,000kPa and AS2885.5 requirements. The five aboveground facilities were leak tested as per ASME B31.3.
Dewatering
Once the pressure tests were completed and approved, Farrant and his team began the dewatering and cleaning process, taking into consideration the stringent requirements to ensure no free water remained in the CO2 pipeline.
“We ran a desiccant dryer with a stage of cleaning and drying pigs to ensure no further water, debris or particles were pushed in front of the pigs as they exited the pipeline,” he said.
“We were working to an acceptance criterion of less than 15mm for the depth of discoloration of the foam pigs after being cut, but we managed to achieve less than 5mm penetration on the handover acceptance pig – which is an incredible achievement for a 53km pipeline.”
The dew point at the end of the drying process was -20°C.
Following the drying process, a commissioning batch treatment was carried out to establish the pipeline corrosion inhibitor consisting of 1:1 mixture of Diesel and Corrosion inhibitor.
After the successful completion of the aboveground leak tests, the pipeline was then N2 purged with less than 5 per cent residual O2 content left in the pipeline with a blanket pressure of 350kPag.
Remote location
Working in the Cooper Basin poses a large challenge in terms of transport and logistics for most companies.
“The Cooper Basin has always been difficult to navigate,” Farrant said.
“It’s remote, dry, hot, and dusty. This posed a particular challenge for our works because it was important, we had clean equipment and a good source of water to complete the testing.”
Pipe Tek set up mobile wash down bays for the Enduro pigs on trailers specially designed to transport the gear in and out. Located at either end of the pipeline during the cleaning and testing runs, the trailers were also set up with satellite communication so the team could receive up-to-date, live information on how the pigs were running.
MPK supplied four 750,000 litre water bladders to push the pigs and fill the pipeline for hydrotesting. The water was then disposed of into a man-made settling dam.
“The extreme heat was also a concern. Our team worked 24 hours a day on split shifts to complete the work on time,” Farrant said.
“To ensure everyone’s safety, we made sure that our trailers were set up with shade, air conditioning, fridges to store food and plenty of water.”
CO2 pipelines represent a critical component in enabling the efficient and safe transportation and storage of CO2, supporting Australia’s efforts in reducing greenhouse gas emissions.
MPK and Pipe Tek’s involvement in successfully commissioning Santos’ Moomba CCS Project Pipeline puts them at the forefront of CO2 pipeline expertise in Australia.
“We’re so proud to have been involved in this project, and met the high expectations of the testing scope,” Farrant said.
“Now, we’re looking forward to getting started on our next challenging project.”
Pipe Tek is a pipeline cleaning, inspection, and testing company with strong attention to detail and a direct approach to safety.
For more information, visit pipetek.com.au.
This article featured in the March edition of The Australian Pipeliner.
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