First of all it takes more than 10 years to build a deep sea oil extraction and they need to drop a couple of billions for the infrastructureThis better not be true. Otherwise, we're f*cked
None of the of the oil- and gas companies that have contracts with FGS are Turkish, which means a separate cut of the revenue for them. The profit-sharing are usually high in the early stages for these entities to recoup expenses for exploration and drilling. Not including corruption and other factors, I'm afraid that only a fraction of revenue will end up in state coffers for development.
I hope there's more to this agreement that we don't know yet.