Well, oil is lighter than water. Cold, deep water should naturally rush in to fill the naturally-abhored vaccum.
Maybe this is where the nuke people come in. Heat it so much that no hydrothermal replacement occurs.
I think a nuke is wrong, rather there are a dozen ways to freeze up the holes, so cold water isn’t forced by nature to
enter.
Hmmm. I was wondering if there was a danger of seabed collapse, causing damages to coastal areas.