I thought the relief wells were simply an attempt to produce oil from the same formation close to the leaking well, at such a rate that the leaking well is relieved from flow.
Now it sounds like they are trying to physically intercept the leaking well shaft above the reservoir and plug it. This would be much more difficult to do.
So which is it?
I believe they intend to intercept the present shaft above the reservoir.
Purpose of releif well is to intercept original well bore and inject cement to permanently plug the wildwell.