Well 42/28d-14 (Tolmount East) was targeting 220 bcf in a previously undrilled area of block 42/28d, 4 km (2.5 mi) east of the 500-bcf Tolmount field.
The well penetrated 73 m (241 ft) of good-quality, gas-bearing Leman sands with a porosity of 16% and gas saturation of 82%, with no gas/water contact was penetrated.
Data collection included logging-while-drilling and wireline acquisition.
Premier will integrate the well data with a new 3D seismic dataset as part of fasttrack development planning for the discovery. It is aiming for project sanction targeted for the second half of 2020.
The result also has positive implications for other targets in the Greater Tolmount area, the company said, such as Tolmount Far East and the Mongour discovery.
The main Tolmount development is due to produce first gas by the end of 2020.