We would not be able to see the plug.

The relief wells we dug deep, then 'turned into the leaking well then 'mud' (a mixture of cement and other stuff) was pumped down the relief well(s) and into the base of the old leaking well.

If we did see the plug, it would not be pretty looking thing, it would more or less look like a plug of cement one would find poured in a fence post hole.