Potentially preventing millions of tonnes of harmful greenhouse gas (GHG) emissions being released from wells into the atmosphere every year, a new technology developed by researchers at Heriot-Watt University uses a chemical injection method described as fast and efficient, which transforms permeable rocks into a solid, permanent seal of insoluble minerals.

The solution can infiltrate even the smallest pores and cracks where existing methods fall short, claim the Rockit initiative scientists, offering a more comprehensive and effective sealing method for both shallow onshore and deeper offshore wells. They predict that the new technique will lock in GHGs deep underground for thousands of years.

The new technology has potentially broader applications, suggest the researchers, including enabling safe carbon and large-scale hydrogen storage.

A fully-functional prototype has been validated under lab conditions and granted an accelerated patent via the UK government’s Green Channel, they add. A US patent application was approved in August 2024.  

Commenting on the new technology, Dr Oleg Ishkov, a lead researcher at Heriot-Watt University’s School of Energy, Geoscience, Infrastructure and Society, says: ‘Using existing methods, research suggests it would take over 300 years to plug millions of at-risk wells on the planet. Our technology offers a radical new solution by transforming porous rocks into impermeable barriers, locking harmful gases underground for millennia.’

Based in Edinburgh, the Rockit initiative has been accepted into Scottish Enterprise’s High Growth Spinout programme, securing £75,000 in funding for further development. 

Report evaluates shut-in offshore well ‘opportunity’  

Meanwhile, focusing on deeper offshore wells, a new report from the UK’s North Sea Transition Authority (NSTA) highlights a ‘huge opportunity to access [oil and gas] resources in a more timely, clean and cost-effective way’ while ‘support[ing] the UK’s supply chain’.  

The NSTA 2024 Wells Insight Report reveals that well intervention is currently able to provide hydrocarbon production at a cost of less than £12/boe, ‘a very attractive option at today’s oil and gas prices’. In addition, it notes that ‘well intervention requires fewer operational days, less construction material, minimal waste disposal and lower fuel burn than drilling a new well, and therefore produces lower emissions’.

Operators should strive to increase their well intervention activity to extend the production lifespan of their wells, and to provide a stable flow of work for the UK’s supply chain, suggests the report. ‘Suppliers, including rig owners, are increasingly seeking opportunities overseas due to a lack of contracting opportunities in the UKCS. It is vital that this capability is kept in the UK to deliver the floating wind, carbon storage and hydrogen projects which will accelerate the energy transition,’ says the NSTA.

Interventions increased in the Northern North Sea (NNS) to 102 wells in 2023, up from 82 in 2022, according to the Authority’s figures. There was also an increase in West of Shetland (WoS) where nine wells benefitted from intervention work in 2023, up from two in 2022. However, Central North Sea (CNS), Southern North Sea (SNS) and the East Irish Sea (EIS) experienced a decrease in activity.

To encourage more interventions, the NSTA has held one-to-one sessions with leading North Sea operators and completed a detailed study of the 795 shut-in wells to understand what percentage could be brought back into production. Based on this work, a supply chain and operator workshop is planned for the end of the year.

Carlo Procaccini, NSTA Chief Technical Officer, comments: ‘Well intervention work can and does produce impressive results, boosting efficiency and providing cleaner and cost-effective production.’

Separately, the report reveals that total active well stock on the UK Continental Shelf (UKCS) is now 2,546, down from 2,560 in 2022. The past year has also seen an increase in the number of shut-in wells to an all-time high of 31% of the active well stock, or 795 up from 742 in 2022.

A proportion of the shut-in well stock could be brought back online, claims the NSTA. However, without investment in infrastructure or downhole interventions, it is likely that many of these wells will be permanently decommissioned, it adds.

Where reactivation is not feasible, wells should be decommissioned in a timely and cost-effective manner, it continues. ‘Disappointingly, industry only achieved 70% of planned well decommissioning activities last year as operators continued to defer work,’ notes the NSTA. It recently opened investigations into missed deadlines as part of its approach to boosting compliance and tackling the backlog of wells awaiting plugging and abandonment. ‘As with well interventions, well decommissioning should provide a sustainable and lucrative source of income for the supply chain,’ says the Authority.

The report also shows that operators drilled 11 exploration wells, two of which were repurposed as producers, and five appraisal wells in 2023. Total exploration and appraisal well spend was £571mn (£287mn in the CNS, £84mn in the NNS, £95mn in the SNS and EIS combined, and £104mn in the WoS). This compares with £275mn in 2022. Industry spent £1.42bn on completing 41 new development wells in 2023, slightly more than in 2022 and in 2021. The CNS saw the highest spend of £678mn, with £235mn in the SNS and EIS, £299mn in the NNS and £208mn WoS.