Italy’s oil and gas giant Eni has taken significant strides forward by drilling an appraisal well in the UK sector of the North Sea, aiming to assess the potential for carbon capture and storage (CCS) at a long-depleted field.
As highlighted in a recent social media announcement from Petrofac, the Hewett field reached a poignant milestone after 56 years of production. The last operational team departed the platform on their final flight, marking the commencement of the ‘lighthouse mode’ phase for the complex. This phase signifies a shift where the asset is neither actively crewed nor operational but remains in place until complete removal.
David Williamson, Offshore Installation Manager at the Hewett field, reflected on this historical moment: “It was an honour and privilege to lead Petrofac’s fantastic team to this milestone, along with my back-to-back, Dave Alger. Like any ultra-late-life asset, we faced numerous challenges, but with the commitment and proactive approach from everyone involved, we completed the project safely.”
While Petrofac’s active role has concluded, the company will continue to serve as the duty holder and pipeline operator until the platforms are fully dismantled.
Hewett, located 22 kilometers off the Norfolk coast, was one of the longest-serving gas fields in the UK continental shelf (UKCS). Since its initiation in 1969, the field has been instrumental, producing a staggering 3.5 trillion cubic feet of gas before permanently shutting down in 2023.
Currently, the decommissioning effort for its six platforms is halfway done, with three platforms already dismantled and removed by Scaldis. The remaining three platforms, known as the Central Complex, are slated for removal next year.
Despite this closure marking the end of gas production, the Hewett field is being repurposed for Eni’s Bacton CCS project, breathing new life into its depleted reservoirs. The North Sea Transition Authority (NSTA) recently reported that the first appraisal well has been drilled at the Hewett field, an important step in exploring its carbon storage capabilities.
According to the NSTA, the UK continental shelf boasts an impressive potential storage capacity of up to 78 gigatonnes in depleted reservoirs and saline aquifers. This capacity could effectively sequester all the CO2 emissions in the UK since the industrial revolution, emphasizing the significance of this initiative.
The NSTA informed that Eni had contracted the Valaris 72 rig for the well’s drilling, which commenced in May 2025. During this operation, extensive data collection included cutting 270 feet of core and conducting a nitrogen injection test before ultimately plugging and abandoning the well.
Andy Brooks, NSTA’s Director of New Ventures, remarked: “The appraisal well on Hewett – the first drilled on acreage awarded by the NSTA as part of the world’s inaugural large-scale carbon storage licensing round – signifies yet another milestone for the sector as we work to identify and harness further storage opportunities that will move towards development. The NSTA is committed to collaborating with licensees to ensure their plans are both robust and viable.”
In an exciting development for carbon capture initiatives, the UK regulator has granted 21 licenses as part of the carbon storage licensing round, which wrapped up in September 2023. License CS008, which includes the Hewett field, is owned by Bacton CCS Limited, a subsidiary of Eni CCUS Holding.
In May, Eni had announced an exclusivity agreement for a 49.99% stake in Eni CCUS Holding, signing with Global Infrastructure Partners (GIP). This was followed by a definitive agreement in August, which signals further developments in the company’s strategy for its carbon capture and storage operations.