Re: A shaped charge might do the trick.
Like I said, it depends on how accurate the diagram is. It makes it look like the leak is coming from the pipe above the actual wellhead. Is this true? Only in that case could "pinching" the pipe help. The diagram implies leaks down the length of pipe, which implies flow going down that pipe. At least they could try blocking it off along the length so that the only leak would be the one near the well.
I'm assuming that the experienced people working the problem have probably thought of anything I could think of, but explosive closure is something I've looked at for certain aerospace uses.