Another really good post at The Oil Drum, except that they buried the lede - when you attempt to reduce carbon dioxide emissions by pumping CO2 into oil fields and get the "benefit" of capturing oil that would otherwise have stayed underground, "the additional oil puts out more CO2 than is buried."
Damn. So much for that technique.
You could of course bury CO2 someplace besides an active oil field, but that then changes the economics to all costs and no benefits.
This stuff is going to take some work. As I recall, the IPCC counted on sequestration to handle 30% of the needed reductions in CO2 emissions to get a stable atmospheric concentration. I hope their economic analysis was conservative in considering whether sequestration is feasible.