TAQA turned production challenges into an opportunity to maximise recovery from northern North Sea assets – and is now reaping the rewards. Wireline explores a very distinctive late-life extension programme…
What began as an infrastructure integrity review at TAQA’s North Cormorant and Eider hub in 2016 quickly grew into something much more ambitious: a multi-faceted programme of work designed to secure several more years of production. The resulting strategy has transformed the economics of a network of assets and illustrates how taking the time to consider the big picture can deliver tangible benefits.
Production across the hub has increased from around 6,000 barrels of oil per day to a post-project rate of approximately 10,000 bpd. The operational life of the North Cormorant platform has been extended by several years, to the mid-2020s, and – critically – an extended window of opportunity now exists for TAQA to pursue new development prospects. In short, it has reinvigorated a hub which had previously been posing some serious sustainability questions for the operator.
“It’s a great example of looking beyond the challenges and identifying the opportunities,” says TAQA operations director Calum Riddell. “Once we realised the potential, it was important for us to make swift progress and that’s where TAQA is perhaps different from many other operators. Elsewhere it might have taken 18 months to get investment approval, but we were quick to move ahead.”
Otter: better, faster
Representing £57 million of investment, the programme included a number of technical and interdependent elements, including redirecting production from TAQA’s subsea Otter field directly to its North Cormorant asset (prior to this ‘bypass’, Otter was tied back to Eider which in turn exported to North Cormorant). To maintain and bolster production, a multi-phase pump (MPP) system was also installed at Otter.
Meanwhile production at Eider was halted, and the platform converted into late-life ‘utility mode’, with an ongoing role to provide power and system support to the other hub fields.
The initiative has its origins in discussions in early 2016 between TAQA’s operations and subsurface teams about how best they could lock in the future value of Otter, amid some infrastructure integrity issues and concerns about failure-prone electrical submersible pumps (ESPs) in its production wells.
“We recognised that Otter was probably our best performing field in terms of volumes, but there were risks and high costs involved in replacing the ESPs and securing the integrity of the wider hub infrastructure,” adds Calum.
TAQA developed a solution whereby Otter production would ‘bypass’ Eider and flow directly to North Cormorant instead. Detailed analyses showed the project to be feasible and the business was further motivated by the prospect of securing additional production that would extend the working life of North Cormorant significantly.
As plans to execute the required reconfiguration work for the bypass were finalised, work got under way on another crucial strand of the strategy: developing proposals to introduce an MPP and associated topsides equipment to bolster Otter production in the longer term.
“While it was initially seen as a negative that Eider was to shut down, once people could see that what we’d actually done was extend the life of North Cormorant it became clear that this was an overall positive.”
For the MPP work, TAQA linked up with specialist vendor OneSubsea, and did so using what was, for TAQA, a new and distinctive contracting model.
OneSubsea applied a total project management-style framework that would see all design, testing, installation and commissioning of the pump performed under a single contract. It was the first time TAQA had committed to a contract model of this kind, rather than its conventional approach which would have been to source the installation element separately.
This streamlined approach meant challenging deadlines were met, taking just 16 months from contract award to installation by OneSubsea’s integration alliance partner Subsea 7. Brought online in October 2018, the 36km link now constitutes the longest multiphase-boosted subsea tie-back in the UK North Sea. “It proved a very successful approach,” says TAQA’s Ewan Wright, who was a focal point for the MPP package and contributed to the process of reconfiguring the Eider platform. “A highly skilled and motivated team across TAQA, OneSubsea and Subsea 7 worked together to deliver on a very tight schedule.”
The MPP project involved fitting an advanced technological solution into mature infrastructure, a process Ewan likens to installing a state-of-the-art engine in an older car. “The goal is to make everything tick and secure increased performance, although even after completing a thorough and robust onshore testing programme, there were still a few surprises when we turned the key,” he says. “We had teething problems with some of the technical elements associated with the installation of the pump into our infrastructure, but those were swiftly resolved and provided valuable learnings for any future projects of this kind.”
The supply of the MPP added a new dimension to the long-standing relationship between TAQA and OneSubsea. “You build up trust over time and that’s what projects like this are all about,” says OneSubsea’s Mike Barrie. “If ever an operator is looking at what is – for them – a new technology or piece of hardware, they need to trust the supply chain to deliver.” Mike says TAQA was open to the new integrated contracting model. “It has numerous benefits for both parties, but critically it provides cost assurance early in the project and risk can be managed more effectively. It means the supply chain is managing much of the risk rather than it being solely down to the operator – all parties are working towards a shared goal and we all benefit from its successful implementation.
“It also allows the operator to be leaner in terms of its own project management – the process frees up time, money and resources that can be directed elsewhere.”
MPP technology has been developed over the past 20 years, primarily for deployment in large-scale deepwater fields in the Gulf of Mexico and West Africa, but OneSubsea adapted it to create a fit-for-purpose North Sea solution. “We hear a great deal about new technology being needed to unlock reserves, but this is an example of an area where there is technology out there already that could be more widely applied,” adds Mike.
Meanwhile, TAQA’s demonstrable ability to move output directly from Otter to North Cormorant put a new slant on the economics of Eider, reinforcing the view that production from the field was not, in itself, enough to keep the platform viable. “While it was initially seen as a negative that Eider was to shut down, once people could see that what we’d actually done was extend the life of North Cormorant it became clear that this was an overall positive,” says Calum.
It was decided, however, that Eider was still to play a key role in providing power, chemical and system support to other hub fields – a dimension that added to the strength of the economic case behind the strategy.
Powering Eider down
Even though production would be wound down, the overhaul of Eider to enable it to provide utility functions was a complex process. Most importantly, it necessitated a hazard reduction and hydrocarbon cleansing exercise on the platform, allied to a well decommissioning campaign spanning a total of 18 wells – the first such large-scale campaign TAQA had undertaken in the UK. Eider was then declared hydrocarbon-free in early 2019.
In the meantime, the team formed a slimmed-down operating model for the platform. This featured a core crew of multi-skilled staff and streamlined support services that reflected its new, non-production status, while existing staff were redeployed to other TAQA assets. This was supported by a programme of engineering modifications to platform utility systems and a comprehensive update of policies, procedures and documentation in line with this new role.
“The Eider late-life work essentially brought everything together,” says North Cormorant offshore installation manager (OIM) Craig Finlayson. “It has taken the form of a highly efficient model that has significantly reduced operating costs, and it made the capital investment in the bypass and MPP fully viable.
“There were valid questions as to whether it was possible to run the low-cost model on Eider, but we’ve shown we can make it work. In fact, it’s continuing to improve even further as we go through the practicalities of operating something that’s gone from a design on a bit of paper to a live system.”
Craig, who previously had a strategic onshore role co-ordinating the various elements of the overall programme and devised the Eider late-life strategy, was also keen to impress the opportunities presented by the wider initiative. “That side of it was important to me,” he says. “It’s easy to be seen to be focusing on just reducing costs, but actually there are development opportunities in there.”
These new prospects extend to TAQA staff as well. “People are developing into new roles, either on Eider or elsewhere in the business,” Craig continues. “It shows that change does create opportunities.”
He emphasises the symbiotic nature of the new field profile, in which Otter production keeps the hub viable, Eider provides ongoing utility support and North Cormorant assumes an enhanced role as the focal point of the hub. “The offshore teams are very focused on production performance – it’s recognised that Otter has to be operated efficiently as, in many respects, it is the lifeblood of the whole infrastructure,” he adds.
“Overall, I think it’s a great example for the industry of how very mature assets still present opportunities – it’s possible to do things differently by looking not just at a single element, but at the wider infrastructure and the overall economics.”
“It’s a great example for the industry of how very mature assets still present opportunities – it’s possible to do things differently by looking not just at a single element, but at the wider infrastructure and the overall economics.”
In a testament to all parties the overall programme, which has served to reduce annual operational expenditure at the hub by around £30 million per year, was completed on schedule and within budget. The bypass work was completed in late 2017, the MPP was successfully installed in October 2018 and Eider entered utility mode in the spring of 2019.
A programme of development drilling on North Cormorant is now under way – including a rig reactivation programme, and additional sidetracks and well workovers –which TAQA says would not have been viable before the late-life strategy was devised and delivered. Further exploration and development opportunities are also being assessed.
It has also represented a welcome opportunity for people like Ewan, who echoed Mike’s sentiments on professional development. “I asked TAQA for experience in major projects when I first joined four years ago, and they’ve honoured that,” he says. “It’s benefited me hugely in terms of both managing a team for the MPP project and getting exposure to the subsea dimension – I’d only been involved in topsides modifications previously.”
The swift completion of the project is an equal boost for those involved. “From concept to execution was around two-and-a-half years, and for a major subsea project and production re-routing campaign that is fast-track by any measure,” he adds.
The reshaped production profile means the hub aligns with the Oil and Gas Authority’s Maximising Economic Recovery (MER) strategy. Ewan notes: “It secures the future of our North Cormorant and Eider area, locking in significant production value while also securing employment for many people for several more years to come.
“It also shows that our sector still provides opportunities for young professionals like myself to gain experience and develop their capabilities within challenging and exciting projects.”