ONE-Dyas spudded exploration well 42/4-1 on the Darach Central prospect in the Southern North Sea on 16 May 2019. The prospect, located in block 42/4 (P2133), had a dual target of Zechstein Dolomites and secondary Carboniferous (Visean) fluvial and deltaic channels. The structure is large with P10 GIIP of 1,076 Bcf. ONE-Dyas used the âValaris JU-121â J/U to drill the well. On 5 July 2019 ONE-Dyas kicked-off sidetrack 42/4-1Z. On 23 July 2019 it was confirmed that ONE-Dyas had submitted environmental approval to undertake an Extended Well Test at Darach Central. On 28 August 2019 it is understood that operations were concluded and the rig has moved off location. In late October 2019 it was reported by partner Neptune that the well had encountered hydrocarbons.  Licence P2133 is located approximately 20 km north of the Crosgan discovery. Crosgan was appraised in 2014 by RWE Dea (INEOS). The company encountered gas bearing sands in the Carboniferous Yoredale Formation with 35 ft (11 m) of pay in the targeted Whitby Sandstone and another 26 ft (8 m) of pay in various shallow sands within the overlying Upper Carboniferous section. The well encountered the gas-down-to deeper than the gas water contact observed in offset well 42/10b-2Z (drilled in 1995). The Whitby Formation was encountered 265 ft (81 m) deep to prognosis but the sand thickness was less than expected for the well. Crosgan was discovered in 1990 with well 42/15a-2 by Total. The discovery wellâs Bunter objective at 1,162 m -1,202 m was found to be water-bearing. The Permian Hauptdolomit tested at 7.63 MMcfg/d (post acidisation). The Carboniferous aged reservoir tested at 15 Mcfg/d. Licence P1630 was awarded in the 25th Offshore Licensing Round and comprises blocks 42/10 and 42/15 covering a total area of approximately 479 sq km. To the north of P2133 lies acreage operated by partner Spirit Energy from the 29th Frontier Licensing Round and the drilling of Darach could de-risk some of the prospectivity in this area to the north.  Interest in P2133 is held by ONE-Dyas UK Limited (35% + operator), Spirit Energy Resources Limited (35%) and Neptune E&P UK Limited (30%).
United Kingdom, P1630