Offshore operators are increasingly looking beyond exploration to recover more value from existing wells. As mature basins face declining production, ageing infrastructure, and growing numbers of shut-in wells, offshore well intervention is becoming a practical way to restore production, support safe abandonment, and extend the life of offshore assets. For shallow-water environments, jack-up based, riser-supported intervention can provide the stability, access and control needed to carry out more complex work on mature offshore wells.
Talking about untapped value in offshore energy often brings exploration, new wells and new developments to mind. But in many mature offshore basins, the greatest source of value may already be in place.
As production declines and infrastructure ages, operators are increasingly looking at how to recover more from existing wells rather than relying only on new drilling. Many of these wells are already drilled, tied back and connected to offshore infrastructure, but remain shut in or underperforming because access is complex, conditions are uncertain or the economics of intervention are difficult to justify.
That is why offshore well intervention is becoming a more important part of mature asset management. It gives operators a way to assess existing wells, restore production where recoverable reserves remain and plan permanent abandonment where recovery is no longer viable.
We’re seeing this shift first-hand through growing demand for our offshore intervention services and integrated well access solutions, which combine riser systems, offshore engineering and operational support to help customers carry out offshore intervention work safely and efficiently.
This shift is particularly visible across mature offshore regions such as Asia Pacific and the North Sea. In Asia Pacific, recovery rates are falling by around 10% each year, while approximately 80% of offshore fields are now in the brownfield phase. At the same time, an estimated 40% to 50% of wells are shut in. That means a significant amount of production potential is not necessarily gone, but tied up in wells that are harder to access, assess or return to production.
The UK North Sea shows a similar pattern where ageing infrastructure, rising operating costs and complex late-life asset conditions have pushed more wells into non-producing status. According to Wood Mackenzie, an estimated £10 billion of value still remains within existing North Sea wells, so clearly the issue is not a lack of value, but the difficulty of accessing that value safely and economically.
For many operators, intervention offers a more practical and cost-effective option than drilling new wells. In the UK, some offshore intervention campaigns have returned hydrocarbons to production at operating costs as low as $16 per barrel of oil equivalent, a fraction of the cost associated with new developments.
Where production recovery is no longer viable, intervention also supports permanent abandonment, helping operators reduce long-term liabilities and manage ageing infrastructure more efficiently as part of wider offshore life extension strategies.
While the commercial case for intervention is clear, delivering it offshore is not always straightforward. As wells age, intervention work often becomes more technically demanding. Operators are dealing with uncertain well conditions, ageing infrastructure and legacy subsea equipment, all while trying to maintain safe and efficient offshore operations.
For example, across the Asia Pacific region, many operators have traditionally relied on light well intervention vessels using riserless systems. These approaches work well for diagnostics and simpler intervention work, but they can become more limited as complexity increases.
This is particularly true in shallow, mature basins such as Bohai Bay and the Gulf of Thailand, where older subsea infrastructure and uncertain well conditions can demand greater control and flexibility than vessel-based approaches can provide. In these cases, the challenge is not just carrying out the intervention, but selecting an access method that can support the full scope of work once the well is re-entered.
That’s where our approach can help. By combining proven riser-based systems with offshore engineering, analysis and operational integration, we help customers plan and deliver more complex intervention work safely and reliably.
Jack-up rigs and lift boats have been used in shallow water environments for years and are now becoming an increasingly practical option for offshore well intervention. Because these assets are fixed to the seabed, they provide a stable working platform that helps improve consistency and control during offshore operations.
They also simplify the deployment of riser-based systems by creating a wider operating window and making it easier to carry out more complex intervention and abandonment work offshore. Because the platform is fixed to the seabed, the well access system can be planned around a more stable operating geometry, helping reduce some of the uncertainty associated with vessel-based intervention in shallow water.
This approach is well suited to projects involving shut-in wells, uncertain well conditions, riser-based access, subsea intervention, abandonment, subsea tree removal or more complex recovery work. It can also support operators that already have jack-ups or lift boats under contract and want to improve asset utilisation between drilling campaigns.
We’re already applying this approach across active offshore projects. In West Africa, we’re deploying jack-up based, riser-supported intervention to help bring mature wells back into production, giving operators greater control and access to reserves that might otherwise remain stranded. In the Middle East, the same approach is supporting the management of late-life offshore assets, ranging from intervention and abandonment through to subsea tree removal.
There are also clear commercial advantages. Jack-ups and lift boats are already widely used in shallow-water operations and may already be under contract for drilling, construction or maintenance work. Where the campaign schedule allows, intervention activity can be integrated between planned scopes, helping operators improve asset utilisation, reduce additional mobilisation costs and avoid committing to a standalone intervention campaign.
Early engineering and analysis are critical to making this work. Mature wells often come with uncertainty around structural integrity, fatigue life, riser loading and downhole condition. Aquaterra Energy supports this upfront analysis, helping operators assess wellhead capacity, riser loads, vessel or rig interfaces and operational envelopes before the intervention scope is finalised. This gives operators greater confidence in the access method, reduces the risk of offshore changes and improves the predictability of intervention costs.
A significant amount of value still sits inside shut-in wells offshore and the tools needed to access it already exist. With the right well access strategy and engineering support, operators can restore production, improve recovery from existing assets and manage late-life infrastructure more efficiently without the cost and complexity of new offshore developments.
The process starts with identifying the right shut-in or late-life well candidates, then assessing the access requirements, well condition and level of control needed. In shallow-water environments, jack-up based, riser-supported intervention can provide the stability and access needed to carry out more complex well intervention, production recovery or abandonment work safely and efficiently.
As offshore assets continue to mature, intervention is likely to play an increasingly important role in extending field life and unlocking more value from existing infrastructure.
Talk to our team to find out how our integrated well access solutions and intervention expertise can support your offshore assets.
Q: What is offshore well intervention?
A: Offshore well intervention involves accessing existing wells to restore production, improve performance or carry out safe abandonment, helping operators unlock value from assets that are already in place.
Q: Why are so many offshore wells shut in?
A: In mature offshore basins, wells are often shut in due to ageing infrastructure, uncertain downhole conditions and limitations with traditional intervention methods, even where recoverable reserves remain.
Q: When is jack-up intervention better than riserless intervention?
A: Jack-up intervention can be a better option when offshore work requires greater stability, riser-based access or more control than riserless vessel-based methods can provide. This is often the case in shallow-water mature basins where operators need to carry out more complex intervention, abandonment or subsea access work.
Q: Why is jack-up intervention important?
A: Jack-up intervention provides a stable, fixed platform that enables riser-based well access, making it possible to carry out more complex and reliable intervention work in shallow water environments. In West Africa, for example, jack-up based, riser-supported intervention is being used to bring mature wells back into production, giving operators greater control and access to reserves that would otherwise remain stranded.
Q: How does offshore intervention reduce costs?
A: Offshore well intervention restores production or enables abandonment at a significantly lower cost than drilling new wells, often using existing infrastructure to reduce both capital expenditure and risk.
Q: What role does intervention play in offshore life extension?
A: Intervention supports continued production from existing wells, helps manage well integrity and plays a key role in late-life asset management, including safe decommissioning.
Ben Cannell
Innovation Director
Ben is responsible for driving innovation across our oil & gas and energy transition service and product lines. He has spearheaded the development and launch of numerous riser/subsea related products to date, including our AQC-SR and CW connectors, legacy well re-entry and abandonment services for CCS and the digitalisation of both existing and new services.
Offshore Network (2019). Increasing workover efficiency in the Asia Pacific. [Online]. Available here
Wood Mackenzie (2024). An additional $10 billion of North Sea value could be extracted from existing assets if the right fiscal and regulatory regime is established. [Online]. Available here
North Sea Transition Authority (NSTA) (2025). Wells Insights Report 2025. [Online]. Available here
Aquaterra Energy. Intervention and abandonment riser systems. [Online]. Available here
Aquaterra Energy. Well access solutions. [Online]. Available here
Aquaterra Energy. Offshore analysis. [Online]. Available here
