Deepwater Horizon - Transocean Oil Rig Fire

An other question for our drillers here: This well is 13,293 feet from the mudline to TD. If there is a casing blowout say 6,517 feet below mudline that communicates with a porous area or thief zone, could there be a situation where the kill mud cannot build up sufficient vertical height to build enough static pressure to counteract the reservoir pressure even if injected at the bottom with the intercept well(s)?

In other words, is there a scenario in which even the intercept wells will not be able to kill this well?