Is it commercial?

You can google for deep water oil and you can see a Reuters story saying that 8% of deep water production is uneconomic at 80dollar oil. What does that imply for those developing unproven fields with no infrastructure in the region? Such as FAN 1 (assuming the reservoir is good). It seems like the drilling costs have been incredibly high, for FAR to be stumping up over USD30m in cost overruns for 16.5%.There is a risk this is a great discovery but not a great investment. Has anyone run the maths on the cost to get to production and likely lifting costs?
I think we are due for an oil bounce but there's long term risk from oil reserves having soared 60% from oil sands, deep water and shale (worse supply response than iron ore).
I don't fancy getting back in. I hold Cairn which seems much lower risk tome while still having seSenegal upside, but I am skeptical of the economics, and would be very happy if someone could provide some scenarios, not just blind optimism. If this is such a great discovery, a large dilutionary placement at a big discount is odd.