RE:WelshGeo, you seem to know your stuff. Do you think@drunk@noon I was going to reply to a couple of posts here so perhaps I can sweep up my responses here and help to provide an answer to your question (at the end of this note).
Is there Cretaceous under Royston?
This is easy to answer - yes. The Cretaceous is the source rock for all the oil in Royston and probably for the 1.5 billion barrels of oil in the Southern Basin in which Royston sits. It's a visible seismic marker and the Cretaceous is also exposed at surface further to the west where it has a world-class source rock with >2.2% Total Organic Content. This is a highly oil-prone source rock and extends into Venezuela or if you prefer the source rocks extend from Venezuela into Trinidad. Touchstone has mapped these deep seismic horizons for Kraken etc and the question is not necessarily whether there is oil there but rather is there any reservoir. The Cretaceous has been deeply buried and the source rocks entered into the oil window. It is common in thrust belts to see detachment (or slipping) of the rocks along oil generation zones and they effectively are oil lubricated causing slide zones which are visible on the seismic. These thrust fault movements have propagated into the shallower sections and are the migration paths for the oil (and gas) to enter into the structures above. Thus you have a source and a migration mechanism into the thrust sheets that sit above the source rocks. It is not uncommon for this to result in elevated pressures in the shallower zones because the migrating fluids are under higher pressure at depth and cause elevated pressures when they enter reservoir rocks. Above normal pressures are clearly evident at Royston (you can work this out from the pressures that are in the Touchstone press release}. So all the well evidence points towards to active oil migration into the Royston reservoirs from a deep mature Cretaceous source.
Pressure Depletion / Decline Rate / Recover Factor
This is an area which @1explosiveGUY seems to be fixated on (well, apart from well costs, development costs, water injection, the jungle and bankruptcy for Touchstone). It's better to address this by going back to basics. What we know is that there is oil and water in the reservoirs. The bottom oil zone seems to be open at depth (could not be tested deeper and was in oil at TD). The intermediate zone has oil and water, probably oil sitting on a significant aquifer (based on the water cuts). There is little or no gas, and yes there is more gas in the analog Penal / Barrackpore field. What this could mean is that the Penal / Barrackpore field could have solution gas / gas cap drive mechanism and Royston could have a water drive by aquifer expansion. What does this mean for recovery rates? A solution gas drive reservoir has a typical recovery factor of 5 - 30% and a Gas Cap drive (driven by gas expansion) has a typical recovery factor of 20 - 40%. While a water drive reservoir has a typical recovery of 35 to 75%.
All fluids (and gas) removed from the reservoir will drop the reservoir pressure. Gas expansion occurs because of the drop in reservoir pressure and does not add energy into the reservoir which @1explosiveGUY seems to suggest "those other pools had lots of gas to drive up oil productioon by maintaining pressure".
Pressure depletion is a function of how much fluids or gas are removed and if water (or gas) is re-injected back into the reservoir. Touchstone intends to inject water and so there should be good pressure maintenance. So I just don't see the justification for the 50% decline rates (admittedly already down from 1explosiveGUY's earlier 70% decline rates).
So to answer your question.
The oil flow rates from the testing are encouraging, I'm reluctant to say much more than that because the press releases are poorly constructed and I don't get too much more clarity from the video interviews. I am sure the well cost will drop (exploration wells are usually the most expensive) and a lot of water has been produced in Trinidad so I don't think water handling and water injection should be a problem. The key will be in the results of the long-term production test during which hopefully they will run the proper production logs to see what zones are contributing and from where. So that's the information that is needed.
I hope that helps, may not be the definitive answer you were hoping for but that's where we are at the moment.