Sintana in their January 2024 presentation provide a first pass...

Sintana in their January 2024 presentation provide a first pass economics for the development of Shell's Graff light oil discovery. For a 700 million bbl recoverable light oil discovery (~ 2 billion bbls oil in place), and Brent US$50/bbl and 190,000 barrels of oil per day peak production rate from an FPSO, the NPV /bbl in the ground is US$4/bbl.

Given Saturn prospect is at a similar depth to Graff, then Pottermore value of US$5/bbl is reasonable.

Note, the industry when looking at developing an oil discovery, prudently uses a significantly lower Brent oil price than the prevailing one, as if the project won't fly at the discounted oil price, then not worth taking the risk of development of the discovery.