They are currently pumping heavy mud(?) and concrete into the pipe to prevent the leak.
Obama has actually asked for the population to provide an answer, so if it's posted in this thread, does the OP get a lifetime tax break?
The leak is from a well head pipe, that's 3 meters across I believe, pretty big pipe. So no valves to switch off. I think plan D is to cut the pipe, and cap it, but would take many months to organise.
My method of madness would be to drill a small hole in the pipe before the leak, then sink a sheet metal down to the site, before the leak but after the drilled hole, severing the pipe in two, but the drilled hole would create backpressure in the pipe, thus sucking the plate metal into place, forming a seal, the drilled hole can then be tapped and drained off at a lower pressure than the backpressure, (as it's being pumped upto the surface), while the block is welded, and everything is under control.
Do I win?