Not sure what you call them. It's a little out of my area of expertise, but a close friend of mine is a geologist and contracts to various oil companies to help them find oil. He goes all over creation doing this. In the past four or five years he said they have been investingating wells in West Texas that were long ago capped because they were thought to have played out. Many of these old wells they've looked at are producing oil again in sufficient quantaties so as to make them profitable. Of course, this is especialy true at the current price of crude, but whoever he's working for has been doing this for some time now.
Today’s production techniques sometimes can re-enter a plugged and abandoned well and put it back on production. However, when and if prices decline to their lows of a few years ago those same wells will be shut-in and taken back off production because of economics.
What your friend is doing is not uncommon with today’s prices and the re-entry process can be very, very expensive in of itself. It is not “just go out and turn on a valve”. Often times a re-entry will result in adequate production for a short time and then declines into “uneconimical” once again resulting in abandonment.