Australia

The National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA), the Australian Government’s offshore energy regulator responsible for health and safety, well integrity and environmental management for offshore oil and gas, has accepted Woodside Energy’s plans to decommission the Minerva Field.

The field, previously operated by BHP Petroleum, is located in Commonwealth waters with the wells laying approximately 11 km southwest of Port Campbell in water depths of approximately 50-60 m. Woodside plans to remove all subsea infrastructure and equipment from the seabed associated with the Minerva development. According to NOPSEMA, activities covered by the decommissioning include:

• Ongoing field management activities (inspection and monitoring) for the Minerva subsea and well infrastructure until decommissioning;
• Removal of the Minerva gas pipeline bundle in Commonwealth waters. The pipeline comprises of approximately 4.9 km of 10-inch concrete coated rigid-steel flowline, bunded with an electro hydraulic umbilical and two 2-inch steel chemical injection lines and stabilisation materials;
• Removal of Minerva subsea infrastructure within VIC-L22 in Commonwealth Waters comprising of five inline pipeline structures, five tie-in spools, and associated equipment and stabilisation material.

Equipment removal activities are planned to commence as early as Q4 2024 and require approximately three to five months, subject to vessel availability and weather constraints.
The plans for the decommissioning were submitted to NOPSEMA earlier this year. Click here to learn more.

The Australian Institute of Marine Science (AIMS) and Australia’s Nuclear Science and Technology Organisation (ANSTO) have begun an investigation to explore the risk of radioactive materials accumulating in marine organisms following the decommissioning of offshore oil and gas infrastructure.

“The experiment will help operators and regulators understand the environmental risk of infrastructure like pipelines with residual levels of NORM (Naturally Occurring Radioactive Material), helping to guide decision-making around whether this infrastructure should be removed or safely left in the ocean,” said AIMS Researcher and experiment lead, Darren Koppel.

According to AIMS, naturally occurring radioactive elements in soils, rocks, the seabed can be accumulated in infrastructure like pipelines. The resultant accumulated NORM that can build up may be present in structures and, if left in the ocean following decommissioning, may eventually leach into seawater before being released into sediments on the ocean floor. This could have an impact on marine organisms.

Currently, there is little data available which describes at what levels NORM from the industry becomes dangerous to marine organisms, a problem the experiment is looking to remedy.

Experiment method

Using facilities in the National Sea Simulator at AIMS’ Townsville headquarters, scientists have dosed marine sediments collected at the AIMS jetty and beach with specific amounts of NORM, and then placed the organisms in the sediments to determine concentrations above which the organisms may start experiencing harm.

The team also extracted eDNA from the sediments to understand and characterise the bacteria biodiversity, and to see whether the radioactivity brought about a change in the bacterial community over the course of the four-week experiment.

“The default position in Australia is that all offshore oil and gas infrastructure must be removed from the ocean when it is no longer being used,” remarked Koppel. “But leaving infrastructure in-situ may be allowed if the oil and gas operator can demonstrate this will result in an equal or better environmental outcome than removing it, that any environmental risks and impacts will be acceptable, and leaving it will comply with Australia’s obligations under international conventions.”

AIMS scientists are also investigating other aspects of the decommissioning question, including the habitat value of offshore structures and whether they can help maintain populations of marine species (including invasive ones and those important for Australian fisheries) by aiding dispersal processes.

Cutting Underwater Technologies has announced the successful completion of all required cuts for a key client as part of a large decommissioning project offshore Western Australia.

The company's proprietary 315” cutting machine, which it claims is the largest of its kind, was used to deliver the project. Four cuts of as much as 6-m diameter performed by a diamond wire cutting machine were executed with precision.

In 2024, CUT has completed 32 projects across six continents. The company's full suite of cutting solutions covers a wide range, from chain cutters and pipe/conductor/riser cutting machines to the largest machines for mid-water arches, disconnectable single-point moorings, and most recently, riser turret mooring structures.

CUT have exclusive use of a patent for castellated/step cuts, which have been recommended by the Government of Western Australia (Department of Energy) to minimise risk in decommissioning offshore platforms. The completion of a step cut mitigates against any danger of structural members such as platform legs sliding or having horizontal movement relative to the bottom part once cut. A step cut would provide structural stability, even with the top part of the platform resting on the bottom part. Cuts can be done remotely, in air, or subsea, removing the risk of having personnel in the cutting vicinity.

Imrandd has delivered advanced inspection data analytics and integrity service for a major upstream operator in Australia, expanding its global footprint

The work determined the future condition of a caisson on an offshore asset, reliably confirming its integrity until cessation of the production facility. The project holds marked significance in saving operational costs as it eliminated the need for a very expensive caisson replacement project.

For the Australian E&P business, Imrandd’s team of data scientists and engineers used their propriety technologies to collate and condition data sets from two existing ultrasonic corrosion mapping inspections conducted several years apart. Rather than using the conventional industry approach where uniform corrosion rates are assumed, the company utilised advanced corrosion growth models that account for changes in both corrosion extent and depth, with statistical analysis of the thickness variations between inspections providing the basis for more representative future condition estimates.

Imrandd CEO Innes Auchterlonie said, “We are thrilled with the results of our first project in Australia, which demonstrates our ability to deliver high value asset integrity analysis and recommendations that allow our clients to make informed decisions that count. Our blend of advanced technologies and experienced specialists deliver actionable insights, arming our customers with the right information to reduce operational costs, enhance integrity and extend the life of assets.

“By highlighting issues before they become critical, operator’s integrity management strategies can evolve from reactive to proactive. As the energy transition ramps up, this approach is not just applicable to oil and gas assets but any sector with safety critical equipment and infrastructure.”

McDermott has announced the safe and successful decommissioning of the Campbell platform and associated offshore infrastructure at the Varanus Island hub in Western Australia

Under a contract awarded to McDermott in January by Santos, the company provided engineering, procurement, removal, and transportation of the platform topsides, substructure, and associated items to an onshore facility for dismantling and disposal.

"The successful removal of the Campbell platform topsides and substructures leveraged our expertise in circular practices and subsea project execution across the energy value chain," said Mahesh Swaminathan, McDermott's Senior Vice President, Subsea and Floating Facilities, McDermott. "This demonstrates our commitment to support clients in tackling complex challenges with creative problem-solving solutions that enable offshore decommissioning efforts and circularity across Australia's energy sector."

The deployment of a custom-built lifting cradle was central to the project's success. Designed and constructed at McDermott's Batam fabrication yard, with engineering support from teams around the world, the lifting cradle was specifically engineered to address the unique complexities of the platform's upper substructure.

ASCO, a UK-headquartered logistics and materials management company, has completed a contract with Onslow Marine Support Base (OMSB) in Western Australia in support of the offshore decommissioning sector.

Two radiation safety officers (RSOs) as well naturally occurring radioactive materials (NORM) and mercury monitoring and analysis equipment were mobilised to the OMSB site as per the contract. The RSOs delivered on-site training for NORM awareness, and monitoring for various hazards such as benzene, hydrogen sulphide (H2S) with a particular focus on NORM and mercury.

OMSB Chief Operating Officer, Andre Veder, said, “At OMSB we believe all parts of the supply chain supporting the offshore decommissioning sector requires a robust focus on safety, efficiency and compliance. As part of this, OMSB proactively holds a range of licences including a radiation licence and associated management plan.

“To drive an effective and compliant outcome for the receival, handling and storage of potentially radioactive items, OMSB selected ASCO as its radiation specialist. ASCO’s international experience with radioactive items has allowed projects undertaken to appropriately manage the risks while not impacting the schedule of the works." 

The project was led by senior RSOs John Davidson and Robin Small who helped to optimise the site, ensuring that supervised areas were set up correctly and any contaminated materials were properly managed and contained. The team enhanced OMSB's management plans and risk assessments, ensuring top-tier radiation management and site safety operations.

Australian decommissioning opportunities

While ASCO has been present in Australia for more than 13 years, this contract represents the first time it has delivered NORM services in the Southern Hemisphere, demonstrating its capability and establishes its credibility to operate in this segment here. According to ASCO, this will set the groundwork to confidently invest to further deliver large scale projects of this nature in the country and expects continues growth in the region as the decommissioning opportunities in Australia mount.

Lee Vettese, Business Development Manager - Environmental Services and Decommissioning at ASCO, added, “This contract signals significant growth for ASCO in Western Australia. Our work in the North Sea has led the way in global decommissioning activity for a number of years now and we’re excited to bring that experience to Western Australia."

Bhagwan Marine Limited, an Australian marine services company, has announced that it will commence trading on the Australia Securities Exchange (ASX) as it seeks to pursue a number of growth opportunities.

The decision comes following a successful initial public offering of fully paid ordinary shares. The offer comprised the issue new shares by the company to raise $80mn before costs and received strong institutional support.

This will allow the company to strengthen its balance sheet and enable it to pursue a number of prospective opportunities around the oil and gas, offshore wind, infrastructure, defence and decommissioning sectors.

Australian decommissioning in focus

Bhagwan Chairman, Anthony Wooles, commented, “Bhagwan is now entering an exciting new growth phase with the emergence of the oil and gas decommissioning sector, and the future development of the offshore wind energy sector. I am excited about the opportunities and potential for the company to expand into new industry segments. Bhagwan’s strong operational and safety performance, along with its passionate focus on clients, personnel, culture, and service delivery, will continue to benefit the company as we pursue sustainable earnings growth.”

This step is recognised as the next chapter for a company which was founded in 2000 with a single vessel. Now, the fleet has expanded from increasing demand for its services to a diversified fleet of around 100 inshore and offshore vessels. These will certainly be put to use in the next phase of the company’s journey as it looks to take advantage of the emerging markets in Australia.

Bhagwan Marine has partnered with Linch-pin to deliver the Thevenard Island Offshore Decommissioning Project contract for Chevron Australia.

With special focus on environmental sustainability, the retirement project involves safe removal and the repurposing of nine offshore platforms as reefs.

Collaborative effort

While Bhagwan Marine will be supplying the marine and diving spreads, Linchpin will cover engineering aspects and deploy skilled construction personnel.

A major win for Bhagwan Marine, the offshore services provider is aiming a seamless and successful execution of the project for Chevron. The company is confident of its expertise and ability to deliver complex projects of this nature.