I don't recall having EVER heard anyone say that there was enough gas for several FPSO's especially since FPSO's aren't really used for gas fields. They are usually used for oil. And no one should have been smiling about gas. They were always looking for oil. Gas is far less profitable and far more difficult to get into a form that can be marketed. Gas can be profitable but you need a huge amount of gas if their is no oil or condensate. The only option for biogenic gas is probably LNG which means you need an LNG facility either floating or onshore.
Bottom line is Ntephe didn't have anything to smile about if all they found was biogenic gas unless he was clueless about what it took to produce it or he didn't understand the drilling report. But hopefully he was smiling because we still haven't heard the full story of what was really found.