[Deaf Smith]

First, it is Fracing not fracking.

Then CO2 is expandable (not stable) CO2 will be exiting the production zones and out the well head. Downhole temps will cause CO2 to turn to gas as well as the upstream flow of crude or NG out of the well head.

Nitrogen is more stable for expansion but has problems.

Nitrogen injection of cement could have been the reason for that GOM blowout a few years ago.

[ETL]

Thanks for all that. Sounds like you know your stuff.

Are you in the field? Or did you just sleep at a Holiday Inn last night? That’s from a Holiday Inn TV commercial 10 or so years ago. :)

[Free in Texas]

Water is non compressible. CO2 is. So I don't see how you could get comparable performance out of a gas in fracing operations. But I drilled wells. I didn't bring 'em in or do workovers.

We used compressed nitrogen several times to sweep cuttings out out of the well to free up a stuck string of drill pipe. It never worked. We always ended up spotting oil or shooting off, washing over then tripping in with an overshot and fishing. No fun at all.