© Supplied by DCT Well Slot is a monthly feature where Westwood’s Stephen Coomber looks at drilling activity and rig moves in UK and Norwegian waters.
UK Offshore Well Slot May 2025
As of 23 May, Westwood Global Energy reports there is one exploration and one appraisal well active on the UKCS, at Culzean Deep in the CNS and Crosgan (appraisal) in the SNS. Since the previous report, no wells have spudded or completed.
Exploration drilling in the UK has been decreasing over the last decade, dropping from a high of 17 wells in 2017 to only three wells in 2024. Current challenges are mainly related to the political climate and the fiscal regime, where JVs cannot spend money drilling exploration or appraisal wells if there is no guarantee they can be monetised in the near future.
A number of companies have openly stated that they have deferred exploration drilling due to a lack of clarity regarding the future fiscal and licensing regime. Many have asked for licence extensions for those with drilling opportunities.
Although the UK is a mature basin, and some may perceive there is little left to explore for, there have been successes in the last few years, as discoveries have been made at Selene, Gilderoy and Baker in 2024, and Brodgar North and Jocelyn South this year to date. There have also been successful appraisal wells over the last few years at Leverett, Pensacola, Abbey and Crosgan.
Looking forward, there are still prospects that should be drilled. Two could be drilled later this year, although most likely will be deferred until there is more political certainty.
Next year, Westwood has sight of around eight exploration wells that might be drilled, but it is questionable whether operators will drill. These include two firm commitment wells at Shearwater NE and in the Greater Pegasus area, plus four ‘firm’ wells that are part of a Phase C licence commitment. There is an additional firm well on the 33rd Round P2677 Olympus licence, but timing of this well is not known.
The outcomes of the various consultations will impact on future of E&A on the UKCS, but in the meantime, companies are looking elsewhere to explore.
© Supplied by MaerskCulzeanCentral North Sea
The TotalEnergies-operated 22/25a-C8, Z Culzean HPHT development infill well is being drilled from the Culzean wellhead platform and spudded on 26 November. It is targeting the Upper-Middle Triassic Joanne and Judy Sandstone Members of the Skagerrak Formation.
The well will be deepened to an ILX exploration target in the Lower Triassic Bunter Sandstone Member of the Smith Bank Formation. The well will be targeting the crestal area of the field and the crestal part of the exploration target in a tilted fault block in the SW of the Culzean structure.
On 26 February, the well was sidetracked, and drilling of the 22/25a-C8Z well is ongoing. The sidetrack was not planned pre-drill and is assumed to be due to mechanical issues. Westwood estimates pre-drill resources for the exploration target at 67 mmboe, based on analogues.
© Supplied by COSLSouthern North Sea
The 42/14a-3 Crosgan Zechstein appraisal well, operated by ONE-Dyas, was spudded on 22 March with the PROSPECTOR 1 jack-up rig. It is the second appraisal well on Crosgan, targeting the Permian Zechstein Hauptdolomit Formation in a four-way dip closed structure, over an eroded Carboniferous anticline.
The 42/15a-2 Crosgan Zechstein discovery was made in 1990 and encountered gas in dolomitised ooid shoal/peloidal grainstones on the edge of a carbonate isolated micro-platform. The well tested at a maximum rate of 1.28 mmscfpd pre-acidisation and 7.6 mmscfpd post-acidisation.
The 42/15a-4 appraisal well, drilled in 2023, flowed gas condensate at 114 bcpd and 26.5 mmscfpd. A DST is planned for the new appraisal well. The JV has not published any pre-drill volumes, and Westwood is currently carrying resources of c. 350 bcf.
Norway Well Slot May 2025
As of 23 May, Westwood Global Energy reports that there are three exploration wells and one appraisal well active on the NCS, with Omega Alfa in the NNS and Rondeslottet, Hoffman and Slagugle (appraisal) in the Norwegian Sea. The Natrudstilen well was spudded, the top hole drilled and then temporarily suspended as it is being batch drilled with the Omega Alfa well.
Since the previous report, the Prince and Skarv-E (East) exploration wells were both reported P&A oil, and the Natrudstilen, Omega Alfa, Rondeslottet and Hoffman wells have been spudded.
© Supplied by Odjfell DrillingNorwegian Sea
The 6606/4-1 S Hoffman well, operated by OMV, was spudded on 18 May, with the Deepsea Bollsta semi-sub. The high-impact well is targeting the Upper Cretaceous. Vår Energi reported pre-drill resources of 120 mmboe.
The Aker BP-operated 6405/7-4 Rondeslottet well was spudded on 16 May, with the Scarabeo 8 semi-sub. The high-impact well is targeting the Upper Cretaceous. Aker BP reported pre-drill volumes of 700 – 1,000 mmboe and JV partner Vår Energi 870 mmboe.
The 6507/5-12 S Slagugle appraisal well, operated by ConocoPhillips, was spudded on 31 March with the Deepsea Yantai semi-sub. The well is appraising the Lower Jurassic – Upper Triassic. The Slagugle discovery has resources of 45.9 mmbbl of oil and 7.1 bcf of gas.
The Aker BP-operated 6507/5-13 S, A Skarv-E (East) well was completed on 10 May, after being spudded on 26 February, with the Scarabeo 8 semi-sub. The 6507/5-13 S well encountered oil in multiple Lower Cretaceous layers. A 14m oil column was encountered in the Middle Jurassic in a 43m thick sandstone reservoir. Other formations in the Middle to Lower Jurassic were water-bearing.
The 6507/5-13 A well was drilled to appraise the Lower Cretaceous discovery and encountered a water-bearing reservoir. The well has been P&A for oil. The JV will consider the Middle Jurassic discovery for a potential tie-back to the Skarv FPSO.
© Supplied by BPNorth Sea
The 25/1-14, A, B, C Omega Alfa well, operated by Aker BP, was spudded on 6 May with the Deepsea Stavanger semi-sub. The well is being drilled to confirm re-migrated oil accumulations in the Eocene, following gas production from the Frigg and Øst Frigg fields. Aker BP reported pre-drill resources of 40 – 135 mmboe.
The Aker BP-operated 30/11-16 S Natrudstilen well was spudded on 30 April with the Deepsea Stavanger semi-sub. The well was temporarily suspended on c. 5 May as it is being batch drilled with the Omega Alfa well programme.
The OKEA-operated 31/4-A-23 F, G Prince well programme was completed on 11 April, after being spudded on 15 November 2024, from the Brage platform. The well encountered hydrocarbons in the Upper Jurassic target, but volumes are reported as lower than the pre-drill estimates of 8 – 52 mmboe.
