So, if all they had to do is put a valve on it would result in an immedate blowout below the sea floor and then it would be totally uncontrollable until the relief wells were completed. By doing it they way they are at least they can capture a majority of the oil.
So how long you think until it's under control - safely?
One of the threads at the Oil Drum touched on some of the intricacies involved with intersecting the target well ...the first Relief well is within 200 feet laterally...still need to drill several thousand feet at an angle to get where they need to be.
Then they start doing the mud action followed by the cement action...since they seem to be uncertain just what they might find.,...I would doubt anyone is going to give dates when it is stopped.
A semi-educated guess would be 30 days. Maybe a little sooner, maybe a little longer.
From now on the drilling will be much, much slower and alot of things could go wrong and cause delays.
Most people do not realize that drilling an oil well starts out with a “plan”. A very flexible plan as nothing ever goes according to plan. Not like building a house but more like fighting a war. Everything can be fluid, changing by the hour or minute and constant changes and adjustments have to be made.
On time and on buget is a rarity.