It's hard to use Orbost as a comparison because Orbost needs to be basically rebuilt every time it switches fields to handle different levels of H2S, mercury, CO2 and condensate. They need to add an expensive H2S removal plant for this rebuild which won't be an issue in Waitsia. So it's probably not a very good analogy for AWE's costs.
Assuming they can use all four existing wells for production I don't think they'll need to drill many wells up front (I think they will be able to maintain 25 TJ/d per well choked back for the first year or more) so can hopefully fund future drilling mostly out of cashflow but I certainly think $150-200M net to AWE is in the ballpark for getting from FID to first gas, funded with a mix of debt and equity.
My calculations show significantly more value than $50M for AWE though.
AWE Price at posting:
51.0¢ Sentiment: None Disclosure: Not Held