© 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 April 2025
As of 25 April, 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 been spudded or completed.
© Supplied by TotalEnergiesCentral 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 CamarcoSouthern 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 April 2025
As of 25 April, Westwood Global Energy reports that there is one exploration well and one appraisal well active on the Norwegian continental shelf, with Prince in the northern North Sea and Slagugle in the Norwegian Sea.
Since the previous report, the Skarv-E (East) exploration well has been completed, with results pending, and Slagugle has been spudded.
© Supplied by Odfjell DrillingNorwegian Sea
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 Åre Formation and Triassic Grey Beds within a combination sub-crop trap at the BCU, associated with a tilted fault block. It is the second well to appraise the Slagugle discovery.
The 2020 6507/5-10 S Slagugle discovery well, drilled c. 1.1 km to the north, encountered a 255m oil column in the Åre Formation and Triassic Grey Beds. The 2022 6507/5-11 appraisal well was drilled c. 750m SE of the discovery well, at a similar elevation at the Åre Formation level and downdip at the Grey Beds level. It was drilled with the intention of obtaining good core samples and performing interference tests, however, the target sandstones were water-bearing.
The main objective of 6507/5-12 S appraisal well is to confirm potential recoverable volumes, fluid properties and well performance towards a potential development. In the NOD’s 31 December 2024 Resource Account, published in February 2025, the Slagugle discovery is held with resources of 45.9 mmbbl oil and 7.1 bcf gas (47.1 mmboe).
The Aker BP-operated 6507/5-13 Skarv-E (East) well was completed on 18 April, after being spudded on 26 February, with the Scarabeo 8 semi-sub. Results are pending.
The well was targeting the Middle Jurassic Garn Formation, of the Fangst Group, in a faulted trap. There was additional potential in the Lower Jurassic-Upper Triassic Båt Group. Aker BP reported pre-drill resources of 5 – 15 mmboe.
© Supplied by OKEANorth Sea
The OKEA-operated 31/4-A-23 F, G Prince well programme was spudded on 15 November 2024, from the Brage platform. The 31/4-A-23 F well was plugged on 8 January, and the 31/4-A-23 G well kicked off on 10 January.
The 31/4-A-23 F & G wells are exploration wells, targeting a play based on a new interpretation incorporating data from the 31/4-A-13 D, E Kim/Sognefjord Øst discovery well drilled last year.
The prospect has an Upper Jurassic Sognefjord Formation target, assumed to be in one or more fault compartments, to the south of the Brage field, downdip of Kim/Sognefjord Øst.
The Prince wells are extended reach wells drilled from the Brage platform, similar to the Kim well, although it is currently not known exactly where the bottom hole locations are. On 30 January, OKEA reported pre-drill resources of 8 – 52 mmboe.
