The West Shetland Basin is characterised by challenging climatic conditions and limited existing infrastructure. A small number of oil fields have been brought onstream and the first gas fields Laggan and Tormore came onstream in 2016. However much of the basin is under explored and considered frontier. The Rona Ridge and Judd High plays have been the focus of exploration in the basin to date.We assume that there is potential to make sizeable discoveries (in terms of the UK) in the future in the basin. The largest future discovery under our assumptions is 100 mmboe on the Judd High.