Usually the expectation is that the expensively-injected CO2 will dissolve in the water that fills abandoned oil fields, which creates carbonic acid and probably starts a series of chemical reactions with the rock. Of course, there are serious corrosion issues during the injection phase. Those problems will likely be even worse if later recovery of the CO2 requires producing hot wet acid gas up steel-lined wells. Getting the CO2 back will probably be even more expensive than was injecting it in the first place. What a waste of limited precious resources!
The whole concept is simply Bad Engineering. Good engineering would be putting the valuable CO2 to productive use immediately.