Shell will acquire a 70% working interest in Licence P2252 from Cluff Natural Resources and will be appointed licence operator. In addition, Shell has the option to acquire a 50% working interest in P2437 before the end of April 2019.
P2252 is located to the north west of the Breagh gas field. Cluff has identified a number of exploration and appraisal targets within Zechstein carbonates. The main prospect is the Pensacola prospect.
The Pensacola prospect is a Z2 Zechstein reef partially mapped on 3D seismic data. The reef is 15km long by 6km wide and clearly defined on 2D and 3D seismic with a distinct fringe and core which builds to more than 200m above the surrounding Z2 Hauptdolomite platform.
Similar Zechstein reef structures produce hydrocarbons in Poland, Netherlands and western Canada but are untested in the UKCS. Cluff believes that the Pensacola prospect can be a play opener with significant follow-up potential in similar structures identified on adjacent blocks.
Gas has already been proven in the Zechstein on block in the three wells drilled to test the Lytham-Fairhaven structure and the overlying anhydrite provides a seal. The fringing reef is expected to contain better carbonate reservoirs than the reef core. The core may have reservoir potential or can be comprised primarily of anhydrite based on the seismic reflectivity of the internal zone. The fringing reef is estimated by Cluff to contain recoverable resources of between 133 BCF and 650 BCF with a P50 of 270 BCF. If the reef core consists of reservoir rocks then an additional 67 BCF to 347 BCF is potentially present.
Cluff and Shell have agreed on the following work program for P2252 to support a well investment decision before the end of 2020:
- Acquiring 400km2 of new broadband 3D seismic data over the Pensacola prospect in the summer of 2019
- Processing of new and existing seismic data
- Subsurface studies
P2437, on which Shell has an option for 50% working interest, is situated in the Rotliegend Lower Leman Sandstone play fairway, on the eastern edge of the Sole Pit Inversion. The Lower Leman Sandstone is the proven petroleum system in the basin with several fields including Barque, Mimas and West Sole. One discovery has been made on the block (Sloop).
The main prospect, Selene, is a NW-SE elongated closure located on the northern limb of the Sole Pit Basin inversion axis. The prospect is formed by two south-west dipping fault blocks, truncated at the NW region by De Keyser faults running SW-NE.
Well 48/08b-2 was drilled down-dip of the Selene prospect and was tight due to dolomite cementation of the sandstones. Cluff believes the well was drilled below the gas-water contact and near or on major faults which acted as conduits for dolomite precipitating fluids. Cluff estimates resources in Selene between 105 and 688 BCF.