Reply #48: Ultimately, drilling a relief well still takes several months in any scenario.

[Selatius]

That's what had to be done in the end-game for Deepwater Horizon. All the other attempts BP did ultimately failed because not only was the BOP destroyed, but some of the pipework below the BOP and probably even below the surface of the ocean floor was damaged. Once the relief well was drilled, they could finally get below the damaged pipework and simply jam mud into it through the relief well.