You don’t put the nuke into the bore hole of the well, you drill a well like the relief wells parallel to the leaking well a couple hundred feet apart and the explosion pinches off the leaking well, that is how the russians did it.
we had tactical nukes that went in an 8” gun, so the physics package could be sent down a drill pipe.
Actually, nuking might work.
Am I correct to assume, that you have about 5000 feet of water. Then about 13000 ft of bedrock before you hit the oil and gas?
A small nuke detonated half way down might just solidify the rock around the hole.
It could be a very small device, enough to produce the heat needed.
Oh one last comment... PHU*K the environmentalists....
You lost me at fuse