Australia

Esso Australia, a subsidiary of Exxonmobil Australia, has entered into an agreement with Helix Energy Solutions to charter the Helix Q7000 semisubmersible vessel to support decommissioning activity across the Gippsland Basin.

The vessel will join Esso Australia’s growing fleet, with its roster of mobile offshore assets now including Rig 22, the HWT600 and a DOF Subsea Multi-Purpose Support Vessel.

Dylan Pugh, ExxonMobil Australia’s Chair, said, “The Helix Q7000 is a welcome addition to our extensive fleet of vessels and rigs currently operating across the Gippsland Basin. It is the forth mobile offshore asset we have added to our decommissioning fleet, and marks the first time we will be using a light well intervention vessel for subsea work locally.

“We are committed to sourcing the right assets for the work we are completing, given the variety of fields we have operated for over 50 years. Our priority is to remain safe, whilst using fit for purpose solutions which ensure we are meeting our decommissioning requirements.”

The Helix Q7000 is set to support decommissioning activities in Bass Strait from the end of 2023.

Well-SENSE, a downhole sensing specialist, has deployed its FiberLine Intervention (FLI) technology at a large carbon capture and storage (CCS) facility, in an industry-first application.

FLI has already been well-proven in a variety of seismic, acoustic and temperature monitoring applications in the oil and gas sector and has just completed its first geothermal well survey for Eden Geothermal in Cornwall.

The fibre-optic monitoring system has since been deployed for a leading integrated energy operator in Australia and marks the first time that fibre has been used to survey live CCS wells and reservoirs.
The new application in the carbon sequestration sector provides a safe, low-risk monitoring solution in a highly corrosive CO2 environment where traditional intervention solutions are often detrimentally affected.

The energy operator employed FLI in a field trial to study well integrity, CO2 flow characterisation and plume movement within the reservoir. FLI’s distributed temperature sensing (DTS) enabled assessment of the reservoir zones, while its distributed acoustic sensing (DAS) simultaneously acquired vertical and passive seismic data.

Annabel Green, CEO at Well-SENSE, commented, “Our FiberLine Intervention system was selected by this leading operator, to be evaluated as a potential alternative to the use of wireline production logging tools. Our system’s advantages include its extremely compact rig-up, much lighter surface pressure control equipment which uses a static rather than a dynamic seal and a simpler deployment method compared to conventional techniques. FLI also uses a bare fibre that is impervious to the corrosive effect of CO2, which helped to make this intervention possible.

“Several challenges were overcome efficiently, including the requirement to leave the fibre in the well for four days with exposure to strong fluid cross flows, the requirement for immediate Cloud data transfer from the wellsite to the operator’s technical centre and servicing a remote wellsite near live infrastructure. We are delighted that operations were performed incident free with no major NPT events and that our unique technology provided valuable, high-quality data from multiple wells.”

The decommissioning of the Northern Endeavour facility has reached a significant milestone as contractor Petrofac Facilities Management Limited (Petrofac) has begun Phase One of the decommissioning process.

The process will see the Northern Endeavour disconnected from subsea equipment and the suspension of the oil wells.

The facility is moored in the Commonwealth waters in the Timor Sea, between the Laminaria and Corallina oil fields. It stopped oil production in 2019, after being shut down by National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) for immediate breeches in health and safety.

“The Australian Government remains committed to the successful decommissioning of the Northern Endeavour, the removal of infrastructure and the remediation of the Laminaria and Corallina oil fields,” said Madeleine King, Minister of Resources and Northern Australia.

“Petrofac taking operational control is a significant step in the decommissioning process.”

The US$355mn contract was drawn up with Petrofac in March 2022 to deliver the first phase of the decommissioning project.

Engineering company Monadelphous Group Limited has secured a contract to provide operations, maintenance and industrial services to support Petrofac in the decommissioning of the Northern Endeavour Floating Production, Storage and Offtake (FPSO) facility.

The Northern Endeavour is a 274 m long FPSO, permanently moored between the Laminaria and Corallina oilfields, approximately 550 km northwest of Darwin in the Timor Sea. Production began in 1999 and peaked at 170,000 barrels of oil per day.

In 2019, the facility was shut down by NOPSEMA after an immediate threat to health and safety was found at the facility. After owners Northern Oil & Gas Australia went into liquidation, it fell to the Government to maintain and ultimately decommission it.

Petrofac was contracted earlier this year as outsourced operator responsible for decommissioning and disconnection of the FPSO. The scope includes the provision of its unique integrated services, working with both local and global suppliers.

The support to Petrofac represents Monadelphous’ first offshore decommissioning contract with work expected to be completed in the second half of 2023.

It represents a host of new contracts and contract extensions awarded to Monadelphous totalling approximately US$160mn.

As part of the early decommissioning works in Bass Strait, Esso Australia’s wells team is moving to the next stage of plug and abandonment work, applying key learnings from the recently completed conductor removal operations on Kingfish B and Mackerel.

Following its successful work at Kingfish B, Rig 22 will now be utilised for plug and abandonment activities at the non-producing platform, Flounder.

“The professional crew deployed with Rig 22 safely and efficiently completed operations at Kingfish B. The results proved the combination of our capable workforce and the refurbished Rig 22 can deliver world class performance for plug and abandonments,” said Wells Operations Superintendent, Ryan Turton.

“We now have a long programme ahead, and we are excited to further optimise our processes and continue to responsibly meet our plug and abandonment obligations.”

The team is also preparing for the arrival of the DOF Multi-Purpose Support Vessel (MPSV) Skandi Darwin, which is arriving at the Barry Beach Marine Terminal early August.

“One of the MPSV’s first tasks will be to support works at our steel gravity based monotowers, Dolphin and Perch,” said Matt Barney, Marine Field Superintendent.

The MPSV provides a floating support asset that will allow the complete abandonment operations on our non-producing facilities which do not have accommodation based on them.

“The MPSV hosts the workforce and means we don’t have to fly workers in and out of the area each day,” said Matt.

“We’re excited to start utilising the MPSV to expand our capabilities and adopt new technology to identify efficiencies, while ensuring the work can be completed safely.”

Heerema has been awarded a decommissioning contract by Woodside Energy that includes the integrated engineering, preparation, removal, and transport of the Nganhurra riser turret mooring (RTM).

For the project, Heerema will remove the RTM from the Enfield field, located approximately 52 km northwest of Exmouth in Western Australia, by lifting the structure in one piece onto a barge and transporting it o Henderson or another suitable Australian port for dismantling, and recycling or reuse.

Jeroen van Oosten, Heerema’s Chief Commercial Officer, commented, “We are proud to be Woodside Energy’s contractor of choice for removing the Nganhurra RTM. This contract represents our first decommissioning project in Australia and although Heerema has a long history of safely and sustainably removing offshore structures from the North Sea and Gulf of Mexico, we are very excited to continue our responsible decommissioning operations in Australian waters.”

Heerema is looking forward to taking an active role in Australia’s decommissioning ambitions. The removal and subsequent reuse or recycling of offshore infrastructure is an essential final step in the lifecycle of oil and gas infrastructure and aligns with our company values of responsibility, sustainability, and contributing to a circular society.”

 

At D&A AUS 2022, Craig Costello from ASX Listed (T3K) TEK-Ocean Energy Services, provided an in-depth exploration of the company’s work within the abandonment space, explaining how it has inspected, refurbished, revalidated and recertified vintage well intervention equipment and assisted in decommissioning vintage oil and gas wells.

Speaking about wells and well intervention equipment, he presented cases of petroleum production companies with vintage subsea wells. He added that some of those wells were past their design lives and have integrity issues – both known and unknown problems. “The construction and production of these wells provided jobs for many decades. But it’s now time for these legacy wells to be plugged and abandoned, safely and efficiently,” he added.

In many cases, the required intervention equipment isn't readily available via OEMs – often because it has been retired. So this legacy vintage equipment, when it is available, requires revalidation, recertification, refurbishment and adaptation to the specifics of the project, Craig explained. Much of the legacy equipment is said to be redundant tooling.

There's an expectation from those who have worked on these wells for many years and from the broader community that the wells are abandoned safely and in a timely manner. “Increasingly, we're seeing NOPSEMA publishing directions and notices in regard to the decommissioning of wells, setting deadlines, and publishing information papers on decommissioning.”

Moving on, he presented three case studies to the audience, the first being the abandonment of some subsea wells by a semi-sub rig – Esso’s Blackback abandonment in the Gippsland basin; second was another subsea well set from a jackup rig: Esso’s Seahorse & Tarhwine abandonments; and lastly the Intervention Riser System assessment on Laminaria Corallina.

He informed that there were a lot of common themes for the three projects, one of them being that these are vintage subsea wells, with both known or otherwise unknown issues due to the lack of communication with the wells.

In all these cases, TEK-Ocean was able to provide alternative means to monitor the wells and barriers in both open water and drilling riser configurations.

Other common threads on these projects were:
• Intervening on wells past the original nominal design lives
• The vintage legacy equipment requiring revalidation, recertification and refurbishment
• Integrity issues on the wells
• Planning, innovative solution ideation and engineering.

Focusing on the first case study – the Blackback well abandonments – Craig said there were 20-year-old wells that had been shut for almost 10 years without any communications. “They have been lost from the Mackerel platform. So they didn't know the status of those wells. TEK-Ocean was selected as the lead subsea provider for that project for a turnkey solution to abandon the wells, requiring innovative approaches to get communications back to these vintage subsea control modules,” Craig added.

Hence, the scope of supply that TEK-Ocean provided for the solutions included sourcing equipment, conducting risk assessments and implementing a barrier philosophy for operational phases. The customer had supplied the vintage tree running tool and TEK Ocean recertified that.

“Re-establishing communications on these wells was a project in itself. Several pre-rig campaigns were executed to survey the assets, confirm the subsea interfaces functionality and to reduce the cost of the programme. This included ROV inspections, testing, opening and closing valves, cleaning, and debris removal."

Craig said establishing communications on those wells did take some effort as several of them that had not been attended to in a very long time and the equipment wasn’t readily available. “So TEK-Ocean was tasked with carefully assembling together a working system from three partial and broken systems that were available, with limited support and documentation from the OEM. This was successfully achieved.”

Craig informed that the Blackback wells were first attempted to be killed in 2010 via a bullhead operation from the Mackerel platform that was successful in two of the wells but it was later found that one had some internal leaks. “TEK-Ocean was not involved in the original bullhead operations but in the light of diagnostics, it was found that there was pressure on the wellhead above the master valves. Also, in 2015, communications were lost, so those investigations were a part of the 2019 campaign. The customer supplied a tree running tool, a 1980s vintage piece of equipment required for recertification and refurbishment. This recertification was achieved via crosschecking materials, part numbers, compatibility and suitability.”

One risk assessment flagged up that only one tree running tool had been provided. This was identified as a single point of failure and required de-risking because multiple runs of the tree running tool were going to be required. De-risking was achieved via a saver- sub approach that was designed, manufactured and project managed by Tek-Ocean for an integrated solution.

Moving to the second case study, he showed Seahorse & Tarhwine, which is in slightly shallower water in the Gippsland basin with 46 metres of water, and the abandonments were performed from a jack up rig. These vintage wells were drilled in the early 80s and then completed later that decade, but had been shut for five or six years, so they hadn’t been checked for quite some time. “The scope of supply in this case was a full subsea project management service again, using TEK-Ocean ISO accredited integrated management system, including all aspects of project management and engineering. The project execution plan was prepared including rig interfacing, barrier and emergency shutdown philosophies. Again, there was a TEK-Ocean managed pre-rig ROV campaign, including subsea cleaning, testing, to de-risk the rig campaign,” he added.

TEK-Ocean supplied and repaired all the equipment, again except for the tree running tool. In this project, the intervention riser system used was the TEK-Ocean dual bore riser system and this can operate down to 200 metres.

It was again a tight preparation and delivery schedule for this project. However, TEK-Ocean was able to mobilise in good time ahead of the required date set by the customer again with HSE performance and an operation during the peak COVID lockdown period in Victoria.

The third case study was the recent inspection and condition assessment of 1990s vintage Laminaria Corallina IRS. The inspection and condition assessment were carried out for both the upcoming suspension of the wells and for the future abandonment.

While concluding, Craig said that TEK-Ocean has a deep and broad knowledge of installed infrastructure throughout Australia particularly in the Carnarvon & Gippsland basins and that the company can support across all different project types. “These case studies demonstrate the recent projects that have been done in the last couple of years for major operators in the Gippsland Basin. We can help you achieve your cost and schedule goals on subsea well abandonments, and help you maintain a strong HSE performance record. TEK-Ocean is now recognised as a leading Australian company in the decommissioning space.”

The Australian Government has contracted Wood, a leading consulting and engineering company, to oversee the first decommissioning phase of the Northern Endeavour FPSO facility in the Timor Sea.

The Northern Endeavour is a 274 m long FPSO, permanently moored between the Laminaria and Corallina oilfields, approximately 550 km northwest of Darwin in the Timor Sea. Production began in 1999 and peaked at 170,000 barrels of oil per day. In 2019, the facility was shut down by NOPSEMA after an immediate threat to health and safety was found at the facility. After owners Northern Oil & Gas Australia went into liquidation, it fell to the Government to maintain and ultimately decommission it.

Wood will work closely with the Department of Industry, Science, Energy & Resources (DISER) and contractors to ensure the safe, efficient and responsible initial phase of the decommissioning scope.
Ralph Ellis, Wood’s President of Operations across the Asia Pacific region, commented, “The responsible decommissioning of the Northern Endeavour FPSO is of great national interest, with safety, cost, and sustainability in sharp focus throughout.

“We are proud to have been selected by the Australian Government to represent their interests in the first phase of the field’s decommissioning journey. As Owner’s Team, we will leverage our unrivalled offshore decommissioning expertise garnered in mature basins across the world to support the successful delivery of this critical scope of work.

“We look forward to working closely with both DISER and the lead contractor on this important project.”