[oil pan 4]

How many blow outs here there been and how many wells are there?
Well head pressure on a CO2 fed well would likely be no more than 1,000psi. A 1,000psi well blow out will be much easier to control than a 7,000psi well.
A well that has been pumped out has no preasure and the ground doesn't just collaspe. Oil and gas valve heads are rated to something like 15,000 to 20,000psi working pressure. Because the pressure on a new well is expexted to be much higher than 1,000psi.

The oil and water mixture is underground is loaded with hydrogen sulfide and CO2 and it can be acidic enough to burn skin. Adding CO2 isn't going to make it more acidic than it already is.
New well head pressure can be as high as 7,000psi.
The balloon pop argument is a joke right?
Natural gas reserves stay down there for millions of years, they support the ground just fine.
Around Amarillo TX the government pumped helium into the ground from the 1940s until the 1980s and nothing happened. I hear the peak well head pressure was 13,000psi when they stopped filling, triple what they started with at that gas well.
You can just say that you hate pipe lines and everything to do with oil recovery.