DOE has done a lot of research characterizing the resource potential for CO2-EOR both in terms of CO2 sequestration and oil production. The numbers I present in the article are actually pretty modest because they only cover the oil fields that have been studied in some detail, while there remains large categories of potential fields that have not been studied. For example there is huge, but uncharacterized potential for CO2-EOR in the Bakken Shale, where productivity today is low and much oil remains in place. Researchers believe that CO2 in shale could open up billions of barrels more, but since it is new technology no one can say for sure, but they are working on it. The numbers above are also only for the USA, but EOR opportunities in Saudi Arabia and the rest of MENA are pretty staggering if you can get the CO2 there.
There is a good article here where I pulled the data from. The link is a kind of a kluge, it opens up an online magazine and you can find the article on p. 36.
And to all the folks who have a knee-jerk opposition to CO2-EOR simply because it produces more oil I would simply point out that there is no evidence that we are going to stop drilling for oil any time. Demand for energy remains sky high and the reserves continue to grow with technology advances. It it is tough to fight supply and demand.
Personally, I would like to see the oil industry step up to the plate on CO2-EOR and accept that they have a role to play in limiting carbon emissions and do their part by injecting CO2 into their fields. The industry could choose to put more efforts into CO2-EOR rather than drilling in the arctic or other sensitive locations.
I would also point out that the Middle East is going up in flames and as long as we are dependent on those resources we are vulnerable as a nation to disruptions. We have plenty of resources in North America that we can be net energy exporters and compete with Middle East supplies rather than depend on them.