It's what I would call "moderately depleted" - most of the wells...

It's what I would call "moderately depleted" - most of the wells drilled were targeting the oil rim which is why there were some dusters (the oil rim is thin and the seismic mapping wasn't perfect in those days so it was easy to miss and hit the water leg). The gas they produced was mostly reinjected to provide pressure support for oil production so much of that gas is still down there.

That's why 2P gas reserves are still quite high despite it being a mature field. Production is declining quite rapidly though, maximum deliverability is currently sitting about 26 TJ/d which is a drop from about 35 TJ/d 3 years ago. That's a 25% decline in 3 years which is significant and explains why they will need to keep drilling. For comparison after they upgraded Mereenie gas plant in 2019 to start delivering into the east coast market via the NGP, it was capable of in excess of 45 TJ/d.

I have reasonable hope for the Stairway too, it's cheap to develop as they can use existing wells and there are some parts of the field where the Stairway has flowed. They currently have no 2P reserves booked to the Stairway so anything they get from there is upside.