Deltic Energy’s drilling operations at the Selene prospect in the UK Southern North Sea has resulted in a gas discovery. The Shell-operated 48/8b-3Z well reached its total depth of 3,540 m TVDSS on 17 October 2024 and proved a 160 m thick section of Leman Sandstone. The top of the Leman Sandstone was encountered approximately 70 m deep to prognosis with elevated mud gas readings, confirming the presence of gas, observed throughout the reservoir interval and into the underlying Carboniferous basement.
Wireline logging and fluid sampling confirmed the presence of a live gas column above a gas-water contact at 3,370 m which is in the middle of the B-Sand, the key producing interval within the overall Leman Sandstone section. Updated post-well structural maps of the Selene prospect point towards a maximum gas column of 100 m.
Initial indications point towards a high-quality dry gas, typical of production from adjacent fields, with no reported H2S.
Based on the preliminary information available from the well site, Deltic has updated its volumetric model of the Selene discovery and now estimates Selene to contain gross P50 estimated ultimate recoverable (EUR) resources of 131 BCF (P90-P10 range of 95 to 176 BCF).
The combination of a deeper structural crest and a shallower gas water contact has resulted in reduced gas column heights across the structure. The base of the B-Sand and most of the underlying C-Sand are now believed to be in the water leg across the south-eastern part of the structure, with the deeper gas readings from the well now interpreted as residual gas rather than a live gas column.
Following demobilization of the rig which is expected towards the end of next week, there will be a period of detailed analysis of wireline data, core samples, fluid samples and pressure testing data which will further refine the geological model, volumetric estimates and the proposed development plan.
