Vital carbon storage industry gains momentum with landmark appraisal well

• First appraisal well drilled on first-round carbon storage licence for the Bacton CCS project

• Significant milestone reached in UK’s energy transition

• Project builds on recent successes of permit awards for Liverpool Bay CCS and Northern Endurance

The UK’s carbon storage industry has reached an important milestone with the drilling of an appraisal well on the Hewett field, in the Southern North Sea, for the Bacton CCS project.

It is the first carbon storage appraisal well to be drilled on acreage licensed by the North Sea Transition Authority (NSTA) as part of the world’s first large-scale carbon storage licensing round in 2023.  

The appraisal well, operated by global energy company Eni, is an important step towards assessing the carbon storage potential of the UK continental shelf (UKCS). The basin has up to 78 gigatonnes of potential storage capacity in depleted reservoirs and saline aquifers, enough to sequester all the CO2 emitted in the UK since the industrial revolution.

The NSTA estimates that up to 100 stores may need to be appraised to identify the best candidates for storage and help the UK reach its net zero target by 2050.

Hewett, 18 miles off the Norfolk coast, was one of the UKCS’s longest serving gas fields. Its original operator, Phillips, started production from the field in 1969, making Hewett only the third North Sea field to reach this stage, after West Sole and Leman. The field had produced 3.5 trillion cubic feet of gas by the time it permanently shut down in 2023.

Now Eni wants to give Hewett a new lease of life as a carbon store, underpinning its Bacton CCS project. It is thought to be capable of storing up to 10 million tonnes of CO2 per year emitted from the Bacton and wider Thames Estuary area, as well as potentially offering decarbonisation solutions for emitters across the European Union.

Eni contracted the Valaris 72 rig to drill the well – and work got under way in May 2025. Extensive data sampling was conducted, including cutting 270 ft of core and performing a nitrogen injection test, before plugging and abandoning it.

The data collected will inform the development plans for the Bacton CCS project by enabling the operator to build a fuller picture of the reservoir’s post-production characteristics and conditions, including reservoir pressures, possible injection rates, wellbore integrity and leakage risk.

In time, the data will be made available on the NSTA’s National Data Repository, helping to provide a richer data set to all operators looking to evaluate and derisk similar stores.