> way beyond the triple critical
> point of CO2 so it will be a high
> pressure gas

There is no such thing as a "critical triple point" - I think tom is mixing two concepts

Triple point = unique temperature and pressure at which solid, liquid and gas are in equilibrium (i.e. coexist). The triple point of carbon dioxide occurs at a pressure of 5.2 atm (3952 torr) and 216.6 K (-56.4oC).

Critical point = unique T and p at which liquid and gas phases are identical. The critical temperature for carbon dioxide is 31.1°C, and the critical pressure is 73 atm.

Critical conditions for CO2 are quite mild so it tends to exist as a single dense phase in the reservoir. This is GOOD news because it means that (in certain circumstances) there is zero interfacial tension between injected fluid and oil, so you get high displacement efficiency (no trapped oil). But there are lots of other things that can go wrong with a CO2 flood.