In the process of oil well water injection, under what circumstances are positive injection and reve

Normally, both positive injection and reverse injection can be carried out for single-layer injection wells. in general, positive injection, i.e. tubing injection, is often used. if there is a packer downhole, only positive injection can be carried out, while multi-layer injection can only be carried out, because multi-layer layers are separated from each other by a packer.