There is a bit more to it. Shell initially bought Signet's...

There is a bit more to it. Shell initially bought Signet's Namibian assets (2913A/2914B) back in 2014 and then did a deal with Kosmos a few years later where they had a joint agreement to jointly explore various frontier areas. This block was a part of that deal. Long story, but in the end Kosmos wanted out of the agreement and Shell paid $100m and bought back their 45% equity along with a suite of other Kosmos exploration assets. I don't know the valuation split here though, so difficult to determine the Namibian value of this deal.

It is perhaps reasonable to use the original Signet asset purchase by Shell, which Signet returned to investors. By my calculations the deal valued the Namibian blocks at US$54m. Hindsight shows that this appears to have been a good deal for Shell. There are probably a whole load of bits to that deal that we don't know about, so take it with a pinch of salt.

Of course, anyone wanting to transact in PEL87 will take the perceived risks into consideration. That risk will be used to calculate any offer of farmin/buyout. Source rock presence risk looks to have been taken care of. However, as I have mentioned before, the maturity and charge is key here. Charge from the east from the "mature" kitchen into Saturn looks feasible, but the Graff discovery doesn't necessarily help de-risk the charge. A Venus discovery will partly help with the reservoir development risk, but it will not improve source maturity/charge risk any more than what Graff has done.

Just my opinion/s.