How do you open veins in a water well with dry ice?
I have been looking for this info as well. So far I have found that for domestic wells approximately 60 to 80# of dry ice is used while for larger commercial wells up to 800# may be used. If the well has a large amount of casing say over 150 feet one should be able to add the dry ice and quickly cap the well. If there is a lesser amount of casing one risks having the resulting pressure blow out or unseat the casing and losing the seal. In this case one must make some other arrangement to seal off the well below the casing in order to contain the prssure without damage to the seal.
