Coal seam gas facilities across the Surat and Bowen basins in Queensland are undergoing a variety of complex scheduled maintenance work to ensure their reliable and safe operation into the future.

The facilities form part of Australia Pacific LNG’s (APLNG) gas production and pipeline systems, which play a major role in the supply of natural gas to both the domestic and international markets.

As the upstream operator of APLNG, Origin periodically undertakes planned turnarounds to enable maintenance, inspections, and repairs. The latest turnaround is being undertaken at the Condabri Central Gas Plant, near Miles.

The scope of work includes replacing compressor bundles on both low-pressure and high-pressure compressors, replacing the boiler vessel, vessel and piping internal inspections, control valve overhaul and pressure safety valve inspection and overhauls. Work at the Condabri Central Gas Plant commenced in July, with maintenance work planned to continue until April 2023 across four gas facilities across the region.

Origin’s Major Maintenance and Turnarounds Manager, Matt Blunden, said, “Turnarounds are vital because they enable Origin to catch any potential issues before they become a critical risk to people or the environment. “Planned turnarounds take months of planning and are costly, but unplanned shutdowns or outages can be even more expensive.

“Turnarounds provide an opportunity to identify and resolve any maintenance issues that could not have been fixed unless the facility was completely shut down. It also allows for thorough inspections of the equipment that would not be possible if it was in operation.

“Data from our inspections and checks enable our Integrity Engineers to analyse the condition of the plants to improve our maintenance strategies.” Mr Blunden said, “Origin has a continuous program of scheduled turnarounds across its operated assets, which include seven gas production facilities and two pipeline compression facilities.

“Turnarounds are typically delivered on a four-year cycle; however, we are currently assessing our inspection and operating data to determine if this can be safely extended to provide increased periods of safe and reliable operation.

“All completed inspections and maintenance enable compliant, reliable and safe operation of the asset through to the next cycle. “The scope of work is limited to the work that cannot be undertaken safely while the plant is in operation, unless a compelling justification is proven in terms of aspects such as risk, cost and operability of the plant and its equipment.

“Quality is planned into all activities and controlled execution ensures all work maintains the mechanical integrity required to safely shutdown and start up the plant and then safely and reliably operate it at its rated capacity.”

Origin’s Turnarounds Team plan and deliver the scope in a way that minimises production losses in the short term and maximises production opportunities in the coming years. The availability of other gas infrastructure within the network helps mitigate the risk of supply disruptions.

“Wet weather events like those experienced during La Niña weather patterns can present additional challenges in delivering the work,” said Mr Blunden. “When heavy rain occurs, the wetter than normal conditions can impact heavy equipment movements in the rural areas where our gas infrastructure is located.

“The softer ground conditions create ground compaction issues with cranage, and trucking materials and floodwaters can inundate low-lying road crossings. “To meet this challenge, we monitor weather conditions and forecasts closely as part of our lead up to turnaround events. We make a specific decision regarding whether to proceed if conditions are safe, or defer the event if conditions are unsafe.”

Logistics planning and personnel resourcing with COVID hygiene requirements has also provided unique challenges to manage large skilled teams to perform work across the sites.

“As local COVID waves peaked, we focused heavily on masks, separation distancing, hygiene measures, and rapid antigen testing to minimise the impact of COVID on the Execution Team and allow this important work to continue,” Mr Blunden said. “Our management approach is to ensure that everyone at work is mindful of health and safety risks.

“Before any turnaround event is approved to proceed to execution, we ensure all Health, Safety and Environment risks to people, community and environment are identified and fully assessed with approved controls. “This is conducted before each event to capture learnings from the previous events to ensure we are always learning and challenging ourselves on our controls and risk management.

“Thanks to the delivery of this vital turnaround work, we are keeping Queensland’s vital gas infrastructure compliant, reliable and in safe operation.”

Feature image: Work underway to remove and replace a gas turbine during a turnaround campaign at an APLNG pipeline compression facility. Images: Origin Energy